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Final Report on Use of Notebook Computers and Related Ergonomics

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					           Final Report on
Use of Notebook Computers and Related
Ergonomics and Occupational Safety and
           Health Problems




                 2009
     Occupational Safety & Health Council
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




                                                Content
                                                                                               Page No

 1.     Executive Summary                                                                       3-7



 2.     Research Background                                                                     7-8



 3.     Research Rationales                                                                     9



 4.     Strategies for Completing the Study                                                     10


 5.     Stage 1: Expert Interviews on Utilization of Notebook Computers                         11-19
        in Industry

 6.     Stage 2a: Territory Wide Telephone Survey on Utilization of                             20-36
        Notebook Computers

 7.     Stage 2b (Part 1): Field Survey on Utilization of Notebook                              37-58
        Computer by Adult Workers

 8.     Stage 2b (Part 2): Telephone/ Online Survey on Utilization of                           59-67
        Notebook Computer

 9.     Stage 3: Recommendations and Development of Handbook of                                 68-83
        Good Practices


 10. Project Conclusion                                                                         84-88




      Occupational Safety and Health Council                                                               2
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 EXECUTIVE SUMMARY



 1.     Background



          Nowadays the use of desktop and notebook computers are very popular in the workplaces.
 For notebook computers, its mobility provides great convenience to the users. However, due to
 its design characteristics (e.g. keyboard cannot be detached from the display screen), users may
 experience difficulties in maintaining a healthy posture when using it, and may experience
 musculoskeletal discomforts or other health problems after prolonged use. Therefore, the
 Occupational Safety and Health Council commissioned Professor Chetwyn C.H. Chan of
 Department of Rehabilitation Sciences of The Hong Kong Polytechnic University and his
 Ergonomic and Human Performance Laboratory to conduct a research on utilization and its
 related issues on notebook computers in Hong Kong in late 2007. The objective of this research
 is to gain an understanding on the utilization situations of notebook computers and the associated
 Occupational Safety and Health (OSH) issues among the notebook computer users, and then
 suggest recommendations for enhancing the occupational safety and health for the use of
 notebook computers.



          The research was conducted between October 2007 and February 2009. There were three
 stages. Stage 1 was interviews of OSH experts, employers and notebook computer users on
 utilizations of notebook computers and their associated problems. Stage 2 was to launch a Hong
 Kong wide telephone survey on the utilization patterns and health-related issues associated with
 usage of notebook computers. The Survey covered adult workers and school-age children, and
 findings were substantiated by conducting anthropometric measurements on selected notebook
 computer users under real work environment. The data would enable us to identify the personal
 and/or work factors which could attribute to the problems such as musculoskeletal discomforts
 reported as experienced by notebook computer users. Stage 3 was to conduct focus group
 interviews with which recommendations on promoting occupational safety and health of notebook
 computer users were generated.




      Occupational Safety and Health Council                                                               3
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




 2.       Findings

 Sample Size


 According to Comrey and Lee (1992), the adequacy of sample size can be defined as: N=100 is
 poor, N=200 is fair, N=300 is good, N=500 is very good, and N=1,000 or more is excellent.
 Another criterion used is Gorsuch (1983) of which the minimum sample size for 86 items covered
 in this study would be 430. The sample size of the telephone survey conducted in Stage 2a is 500-
 600 for each of the working adult and school-age children groups. The results obtained based on
 the working adult or school-age children group can therefore be regarded as having an adequate
 sample size and of “good” validity. It is important to note that the results obtained for the sub-
 groups such as those who reported using notebook computer versus those who did not, or those
 reported having high level of discomfort versus those who did not, might suffer from inadequate
 sample sizes. Readers should be cautious when interpreting the results and the conclusion drawn
 from the analyses at the sub-group level (see limitations of study). Nevertheless, the sample size
 of the field assessment (N=100) conducted in Stage 2b on the use of notebook computer,
 anthropometric measurements, and bodily discomfort can be regarded as adequate as the data
 generated was based on one-on-one assessment. The criterion used is 30 subjects for small group
 study (Portney and Watkin, 2009). The results obtained in the field assessment are regarded as
 having an adequate sample size and of “good” validity.


          In Stage 1, a total of 57 participants were successfully interviewed out of making 532
 contacts by the research team. The participants were recruited mainly from: (1) finance, insurance,
 real estate and business; (2) social, community and personal services; (3) wholesale and retail; and
 (4) logistic, storage and communication. The participants in this stage were experts in OSH,
 representatives of employers, and notebook computer users.              The results from the interview
 indicated that usage of notebook computers was largely different from before. Nevertheless, the
 conventional functions to be supported by notebook computers such as short duration, out of
 office usage, and presentation and emailing did not seem to be the only utilization purposes




      Occupational Safety and Health Council                                                               4
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 among the users. Rather, notebook computers were reported to be used for prolonged typing-
 related functions such as word processing, surfing the Internet, information search, and data entry.
 Besides the decision of selection, notebook computers could be selected because of limited
 desktop space in offices and/or administrative directives of companies. The interviews of the
 participants did not reveal obvious problems associated with usage of notebook computers. For
 instance, as reported by the participants, they did not aware of existence of musculoskeletal
 discomforts, pain and work-related disorders among the users. The results obtained from Stage 1
 were useful for setting the framework for Stage 2 of the research. The most important finding
 was that utilization of notebook computers seems to scatter across different industries and has a
 wide variety which tends to depend on preferences of the users and their companies’ procurement
 policies.



         The Telephone Survey conducted in Stage 2 was contracted out to the Public Governance
 Program of Lingnan University. The Survey successfully interviewed 517 working adults and 503
 school-age children.      The main finding was that notebook computers (34%) were still less
 commonly used than desktop computers (66%) among the working adults in Hong Kong. It was
 however important to note that about half of the adult respondents indicating using notebook
 computes (51.1%) claimed using them for a prolonged period of time, i.e. longer than six hours a
 day. The prolonged usage was further aggravated by the notion that these respondents used
 notebook computers for typing-related tasks such as word processing (57.3%) and web browsing
 (49.6%). Such utilization patterns were found to be slightly different from those who reported
 using desktop computers in the Survey. The results indicated that musculoskeletal discomforts
 commonly existed in the shoulder neck (26% of the working adults in the Telephone Survey
 (N=517) and 77% in the Field Survey (N=100)), the wrist (14.5% and 29%), and the eyes (9.2%
 and 50%).      The proportion of the respondents reporting having discomforts were found to
 associate with the age of the respondents, the duration of utilization in particularly for longer than
 six hours a day and more than two years, and the use for word processing (and Internet surfing,
 data entry and presentation revealed in the field test). It was found that the discomforts also
 would be aggravated if the users did not report using external accessories such as monitor,
 keyboard and mouse and attending training sessions on occupational safety and health. In fact,



     Occupational Safety and Health Council                                                                5
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 only very small portion of the respondents (11.8%) attended these training sessions. The findings
 from the field assessments and the match between the users’ anthropometric dimensions and the
 workstations further supported the findings. On average, the users’ eye-level was found to be
 higher than the screen of the notebook computers by about 15cm (Min=1.5cm, Max=29cm). The
 elbow height was on average lower than the desktop by about 6cm. The illumination was on
 average higher than the common practices (i.e.300-500 LUX) which was 709.6 LUX. The
 findings from the Survey and field assessment were consistent suggesting the potential of
 developing musculoskeletal disorders among the notebook computer users. The analyses revealed
 the close relationships between awkward posture, improper design of the workstations in
 particularly outside the office environment, lack of training on proper use of notebook computers,
 and bodily discomforts. This can be due to the fact that the current regulation is less easy for
 applying to the use of notebook computers in particularly when these computers are mobile and
 used both in- and out-of the office. The inadequate provisions of the workstations and improper
 utilization of notebook computers are also the main attributes to the problems.


          For school-age children, the percentage of use of notebook computers was less than the
 working adults (16.5%).          The purposes for them to use notebook computers were word
 processing (47.5%), web browsing (42.4%) and entertainment (35.6%). For health-related
 problems, some of the school-age children reported discomforts in the shoulder and neck (16.9%),
 eyes (13.6%), and lower back (10.2%).




 3.       Good Practices and Recommendations



          Based on the findings of this research, the research team suggested recommendations
 which might help notebook computer users to lower the risk of having musculoskeletal- and other
 occupational health-related problems. The principles underlying the Occupational Safety and
 Health Regulation on Manual Handling Operations are to reduce the weight, distance and
 duration for carrying with the notebook computer; encourage regular break during carrying; and




      Occupational Safety and Health Council                                                               6
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 use ergonomic gadgets such as backpack or hand trolley.                  The principles underlying the
 Occupational Safety and Health (Display Screen Equipment) Regulation are to achieve a match
 between the users’ anthropometric dimensions and the workstation; use ergonomic external
 accessories (e.g. external keyboard, mouse, etc.); conduct notebook computer specific risk
 assessments; encourage stretching exercises and taking rest breaks; and providing informative
 training on proper use of notebook computers. Besides, having the potential users and their
 employees to reconsider the needs for using and/or prescribing notebook computers in the
 workplace is deemed crucial. The experience gained in this research is that in most circumstances
 the use of notebook computers in offices was not likely to be necessary. What it means is that
 employers should conduct a thorough needs assessment on notebook computers before prescribed
 them to their employees. A decision tree was constructed and proposed in this report to facilitate
 employers and users make a suitable decision when choosing notebook computers. Last but not
 least, an adapted risk assessment form was constructed to facilitate employers and users to
 identifying occupational health risks from using notebook computer, so that they can implement
 relevant actions for lowering these risks.




 RESEARCH BACKGROUND



         With the rapid development of modern technology, personal computers (PC) have become
 one of the most common used display screen equipment devices in a workplace. There are
 numerous studies which reveal the associations between work-related musculoskeletal disorders,
 occupational health and use of computer in particular when the usage is of extended period of
 time (Bergqvist et al., 1995; Gerr et al., 2004; Leung et al., 2004; Tittiranonda et al., 1999; Sung
 et al., 2003). However, these studies have been involved the use of desktop computer inside the
 office, monotonous work content, and workers’ adopting a sustained sitting posture (Szeto et al.,
 2002, 2005a, 2005b). The findings in general are using ergonomic features such as foot-rest and
 keyboard, maintaining an upright posture with elbow and knee at a right angle, varied work
 content, taking rest breaks and typing less than four hours per day (Leung et al., 2004; Sung et al.,
 2003). The research has also shown that certain workers had tendencies to adopt abnormal



     Occupational Safety and Health Council                                                                7
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 postures and muscle activity patterns which became habitual and contributed to their chronic
 musculoskeletal problems (Szeto et al., 2005a, 2005b).



         Nevertheless, the changes in the ways business and industries conducted have shaped the
 ways which computers are used in the workplace. Because of globalization and concepts of
 mobile business, workers nowadays rely more and more on notebook rather than desktop
 computers. The main features which enable notebook computers to serve their purposes are that
 they are small in size, relatively light in weight and have compact input devices. Because of its
 portability and convenience, notebook computers are now commonly used by businessmen in
 traveling or meeting out of office. Nevertheless, the popularities of notebook computers have
 also created escalating concerns among the users. First and most of all, its small in size has led to
 the fact that notebook computers are also commonly used inside offices. The indoor usage has
 resulted in occupational health issues such as musculoskeletal pain and eyestrains (Blehm et al.,
 2005). It is anticipated that as their sizes are smaller and the screen and keyboard hinged together,
 the musculoskeletal problems arising from prolonged use of notebook computers will be even
 more prevalent than that of desktop computers.


         With a densely populated environment and a boom in economy, Hong Kong provides a
 very limited office space and therefore there is an urgent need to study the utilization
 characteristics and health consequences associated with notebook computer use.                  There are
 several overseas studies reported the use of laptop computers and their health-related issues.
 These studies put their emphases on examining and comparing with the posture and muscle
 activities involved in using laptop computer and those with the desktop computers on healthy
 young adults (e.g. Straker et al., 1997; Szeto et al., 2002; Villaneuva et al., 1998). There are very
 little published data available on the usage of notebook computers and their associated
 occupational health problems. The findings may also not be readily generalized and used as
 guidelines for the local industries due to differences in statutory regulations across geographic
 regions and possible differences in usage habit across the user groups. The proposed consultancy
 study would help to bridge these gaps.




     Occupational Safety and Health Council                                                                8
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




 RESEARCH RATIONALES



         Despite there are a few studies which addressed the utilization of notebook computers and
 the problems associated with their use, their findings might not be applicable to Hong Kong. First
 of all, comparing with that in overseas, the office space of Hong Kong is relatively small; there
 would be a higher proportion of workers using notebook computers in offices. The prevalence of
 occupational health problems such as musculoskeletal pain and eyestrains could be higher in Hong
 Kong. Second, workers in Hong Kong would need to carry notebook computers with them when
 they work outside office and rely mostly on public transportation and walking, it is likely that the
 workers would experience more musculoskeletal problems related to the lifting and carrying of
 the computers than other Western countries. Third, the Occupational Safety and Health (Display
 Screen Equipment) Regulation has only been enacted in Hong Kong for less than 10 years, the
 compliance of safety use of notebook computer could be relatively lower than that of overseas.
 Last, there have been a few reviews and survey studies conducted on the utilization patterns and
 occupational health problems associated with using desktop computers in the workplace within
 the last 10 years; but very few concerning the use of notebook computers. All these factors
 suggest the needs for conducting a systematic review and survey on the utilization patterns and
 potential threats to occupational health of using notebook computers among the work force in
 Hong Kong. This consultancy project is an attempt to tackle these issues.




     Occupational Safety and Health Council                                                                9
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 STRATEGIES FOR COMPLETING THE STUDY
           In order to complete the study efficiently and effectively, we divided the study into three
 stages. The thinking behind separating the study into three stages was that the consultancy team
 needed to develop the ways to effectively narrow down its scope and put focus onto a few
 occupational groups of which the workers were required to use more of notebook computers.
 Within these groups, the workers would present with problems in occupational health.                      A
 knowledge-based focus would enable the team to explore the problems with a considerable depth
 so that the results obtained would have a high level of validity. These results can then be used for
 developing occupational health recommendations and good practices.


           The three stages of the study were: 1) identify occupational groups (or industries) which
 give the highest level of usage and potential for developing occupational health problems; 2) large
 scale survey to review the utilization patterns, risks on occupational health, and potential
 musculoskeletal and other work-related symptoms; 3) expert reviews on development of good
 practices and recommendations of usage of notebook computers – both inside and outside offices
 (Figure 1). The descriptions and methods of each of the three stages will be elaborated in this
 report.
                   Figure 1 Schematic diagram summarizes the plan of the study

                                                                   Stage One
                     Interviews and             Identification of occupational groups with a
                      Focus groups;
                                                           relatively high exposure
                      Literature Analysis




                                                                  Stage Two
                                               Review of utilization patterns and work-related
                     Telephone Survey,         symptoms of school-age children & working
                      Site Interviews and
                      Field Testing;           adult, and specifically conduct risk assessment
                      Surveys                   on working adults in the occupational groups




                                                               Stage Three
                     Focus groups with        Recommendations and guidelines Development
                      stakeholders
                                                     for users of notebook computers


     Occupational Safety and Health Council                                                               10
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 STAGE 1: EXPERT INTERVIEWS ON UTILIZATION OF NOTEBOOK COMPUTERS IN INDUSTRY




 1.     Introduction



          Nowadays, with continuous development of technology, functionality and mobility of
 computer there is an increasing demand of notebook computers used at work. Using of notebook
 computers at work does facilitate efficiency and effectiveness of work; however, there are
 potential risks for the notebook computers users to develop various cumulative traumatic
 disorders (CTD) or musculoskeletal disorder (MSD) (Blehm et al., 2005).



          There is limited literature available in the study of occupational safety and health relating
 to the use of notebook computers. The results and conclusions of these studies cannot be
 generalized to the Hong Kong public and notebook computer users. This study attempted to
 focus on workers in specific local industries or occupational groups who utilized notebook
 computers.




 2.     Methods



          Focus groups and individual interviews were used to gather information in the utilization
 patterns and work-related symptoms associated with notebook computers. Interviewees from
 statutory groups and stakeholders from the different local industries or sectors were recruited.
 The information gathered from these groups will be used to triangulate with the results obtained
 from other parts of the study.




      Occupational Safety and Health Council                                                              11
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 3.     Results



          The potential participants were randomly selected from the Yellow Page/ White Page
 under different industries or from the contact list of different industrial associations. A total of
 532 contacts had been made by means of direct emailing, telephone calls or visits. These parties
 composed of companies, associations and unions across different industries, statutory and
 professional parties, notebook manufacturers and retailers, and notebook users. Approximately
 one-tenth (i.e. 10.7%) of those we had contacted agreed to be interviewed in the form of
 individual or focus-group. The participants who agreed to be interviewed reporting using
 notebook computers at their workplace were from the industries shown in Table 1 and Chart 1.
              Table 1 Summary of Industries from which interviewees were recruited

                                           Industry                                    No. of Participants (N=57)
                   1. Finance, insurance, real estate                                                 16 (28%)
                       and business services
                   2. Social, community and personal                                              10 (17.5%)
                       services
                   3. Wholesale & retail                                                              9 (15.8%)
                   4. Logistic, storage and                                                           6 (10.5%)
                       communication
                   5. Constructions                                                                5 (8.8%)
                   6. Self- Employed                                                                4 (7%)
                   7. Import & export                                                              3 (5.3%)
                   8. Medical Practitioners                                                        2 (3.5%)
                   9. Hotel & Catering                                                             1 (1.8%)
                   10. Manufacturing                                                               1 (1.8%)
                                                 Total:                                           57 (100%)

             Chart 1




                      Finance, insurance, real estate and business services   Social, community and personal services
                      Wholesale & retail                                      Logistic, storage and communication
                      Constructions                                           Self- Employed
                      Import & export                                         Medical Practitioners
                      Hotel & Catering                                        Manufacturing




      Occupational Safety and Health Council                                                                            12
    Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



              The companies, which agreed to participate and be interviewed, came from 10 out of the
     14 industry categories in Hong Kong. The results therefore cannot be claimed to fully reflect the
     actual situation and the prevalence of notebook computer utilization in the local industries.



              When the participants were asked about the purposes and functions of using notebook
     computers at work, the results suggested that the ways notebook computers were utilized are
     quite different from what would be expected. The conventional utilization of notebook computer
     was mainly for facilitating communication in an occasion such as using PowerPoint in a seminar
     or business conference, or emailing while one is out of the office environment such as a trip
     overseas. The utilizations of the notebook computer by the participants are summarized in Table
     2. Most of the participants reported that notebook computers were largely used for PowerPoint
     presentation in all industries except import and export. There was a substantial proportion of the
     participants reported using notebook computers for word processing (Table 2 and Chart 2). The
     findings indicated that the participants would carry out prolonged-typing related tasks such as
     word processing with notebook computers. This further suggested that the participants possibly
     involving sitting in front of the notebook computers and perform on stationary and prolonged
     tasks. The data, however, did not indicate whether these tasks were carried out when travelling or
     in a prolonged manner.



                       Table 2 Summary of Purposes of Notebook Utilization across
                                 Participants from Different Industries

                      Industry                          PowerPoint      Word       Traveling      Email      Internet
                                                                      Processing                             Browsing
1. Finance, insurance, real estate and business             7             3             4           2            0
    services
2. Social, community and personal services                   3             3            1            2           1
3. Wholesale & retail                                        1             3            2            1           2
4. Logistic, storage and communication                       3             2            0            1           0
5. Constructions                                             1             0            3            0           1
6. Self- Employed                                            1             1            0            1           1
7. Import & export                                           0             0            1            0           2
8. Medical Practitioners                                     0             1            1            0           0
9. Hotel & Catering                                          1             0            0            0           0
10. Manufacturing                                            1             0            0            0           0
                               No of Responses (N=57)   18 (31.6%)    13 (22.8%)    12 (21%)     7(12.3%)    7 (12.3%)




         Occupational Safety and Health Council                                                               13
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




              Chart 2




                                          PowerPoint Presentation   Documentation/ Word Processing
                                          Traveling                 Emailing/ Communication
                                          Internet Browsing




         The relationships between the patterns of utilization and functionality of notebook
 computers did not appear to be strong. The responses from the participants indicated that most
 of the utilization of notebook computers involving different extent of using desktop computers.
 One observation was that the participants chose to use notebook computers when they traveled
 and worked overseas.        The participants further suggested that, inside the office, there were
 environmental factors which increased the likelihood of using notebook computers. According to
 the participants, the main environmental factor was limited desktop space inside the office. The
 limited in space did not allow the set up of desktop computer workstations. The use of notebook
 computers henceforth was treated as a solution for making computer work possible as notebook
 computers were smaller in size than desktop computers. Another factor as expressed by the
 participants who came from large size companies was that staff of senior rank tended to be
 provided with notebook computers. The staff was expected to use these computers when they
 traveled overseas. It is however important to know, as these high rank workers from large size
 (or medium size) companies spent most of their workday meeting with clients, it was likely that
 their utilization of notebook computers was for presentation and/or emailing rather than typing-
 related tasks. In contrast, those front-line workers from small size companies tended to be
 provided with notebook computers because of the limited work space in the office and the out-of-
 office duties. The needs for using notebook computers were therefore multi-factorial and likely to
 be influenced by the size of the company, rank of staff, and task requirements. These factors were
 further explored in the rest of this study.




     Occupational Safety and Health Council                                                               14
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




         During the interview, the participants were also asked whether they were aware of the
 occasions of which the employees had suffered from musculoskeletal discomforts or disorders due
 to the use of notebook computers at the work place. It was consistent among the participants
 that these problems did not seem to be obvious in the companies which they worked in. In other
 occasions, the participants expressed that there were reports of musculoskeletal discomforts from
 the employees; however, the difficulties they had experienced were that the majority of these
 cases did not substantiate the causality of the discomforts which were solely caused by the use of
 notebook computers. The common causes of the discomforts, as expressed by the participants,
 were possibly due to prolonged sedentary work, improper work postures, heavy workload, lack
 of exercises, or deterioration of health due to aging etc. As a few of the participants who had a
 medical background alluded on the difficulties of making a confirmed diagnosis of work-related
 musculoskeletal disorders related to use of notebook computers. The problems were further
 complicated by the notion that the use of notebook computers in most circumstances might be
 part of the work duties and it was the only instrument used for carrying out these duties.



         When asked about the known occupational and health issues associated with using
 notebook computers at work, the participants expressed that the problems had not been obvious
 and common. Nevertheless, they expressed that they had experienced difficulties in applying
 existing Occupational Safety and Health (Display Screen Equipment) Regulation for workers
 using notebook computers; and also expressed uncertainties in term of conducting risk
 assessments and guidelines for promoting safety and health to the notebook computer users. The
 main concerns on the existing regulations from the participants were:
             Difficulty in defining the number of hours of utilization by the “users” in particularly
              when the computers were used outdoor and at home.
             Difficulty in defining the term “workstation” for notebook computer users.
             The weight and carrying of the notebook computers not included as part of the risk
              assessment.




     Occupational Safety and Health Council                                                               15
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         Last but not the least, there was one guiding question which tapped on the requirement for
 any personal protective equipment or accessories for the notebook computer users. The most
 frequently equipment items mentioned by the participants were:
         1.    external keyboard and mouse
         2.    external monitor
         3.    notebook dock/ laptop riser/ platform,
         4.    backpack or hand trolley
         5.    availability of one set of desktop computer in addition to the notebook computer



         The use of external mouse and keyboard was recommended as the participants commented
 that the existing notebook computers were comparatively small in size than desktop computers,
 and hence their keyboards were in proportion smaller than the conventional keyboards. Typing
 on a small size keyboard might lead to poor wrist angle, i.e. radial deviation of wrist joint when
 typing. Apart from the keyboard, the participants commented on the designs of the mouse of
 notebook computers. The common designs are touch-pad with which, as they expressed, might
 generate excessive sustained and sedentary movements of the upper limbs and strains on the
 finger joints when compared with the conventional external mouse attached to desktop computers.



         The use of external monitor was also recommended as the participants commented that
 the screen of notebook computers was non-detachable. The fixed level of the screen (mostly at a
 lower level than the users’ eyes) might lead to improper work postures and eye distance. They
 expressed that this might lead to shoulders/neck and eyes discomforts. An external monitor was
 believed to reduce the harmful effects and risks brought about by the design of notebook
 computers because it is comparatively large in size and its height is adjustable for accommodating
 varying eye-level of users.



         The use of dock or notebook stand was also recommended for increasing the adjustability
 of notebook computers for fitting the dimensions of the users. In general, a notebook stand raises
 the height of the screen so for fitting the eye-level of the users. The drawback is that when the




     Occupational Safety and Health Council                                                               16
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 eye-level is accommodated, the level for the input device such as the keyboard and mouse pad is
 too high to the upper limbs. The participants further pointed out that if a notebook stand was
 used, the risks associated with using the gadget might be higher when an external keyboard and
 mouse were not prescribed. The higher the level of the keyboard and mouse is, the higher the
 strain level acting onto the users’ shoulders and upper limbs would be expected. As a result, the
 participants were mindful for making the external keyboard and mouse available to users when a
 dock or notebook stand is used.

          Last but not least, the participants mentioned the value of having a backpack for carrying
 the notebook computers. In particular, they opined that a backpack was crucial if users’ primary
 purpose of using notebook computers was for traveling from one place to another, and to
 overseas.     According to their comments, they considered backpack as the most useful and
 ergonomic-designed bag for holding notebook computers. The counter-arguments against using a
 backpack were more on the appearance of the backpack and inconvenience for those who
 attended official meetings and/or wearing formal dresses.



 4.     Discussion

          The results obtained in this phase of the study suggested that notebook computers are
 likely to be utilized by employees in rather diverse industries; while the participants commented
 that employees in the banking and financial industries could be relatively more often be prescribed
 with notebook computers. Workers in the banking and financial industries are those who require
 to work outside offices for exchanges and marketing, and thus are more likely to be equipped
 with notebook computers for their daily operations. Another group of workers was senior rank
 position and executives in the banking and financial industries who can be regarded as
 conventional users, i.e. notebook computers used for making presentations and emailing.
 Nevertheless, the findings of this study suggested that the utilization of notebook computer was
 observed in diverse industries, and there was no one industry in which notebook computer were
 dominantly used; it is therefore concluded that utilization of notebook computers is likely to be
 industry independent.




      Occupational Safety and Health Council                                                              17
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         The preference of notebook computers to be used in a single or a few specific industries is
 not obvious. It is likely that the utilization of notebook computers is not industry-specific but
 company- and function-specific. The results indicated that utilization of notebook computer
 tended to be driven by the specific functions of the job duties and how the notebook computers
 facilitated them to deliver such functions. Notebook computers were also commonly used by
 employees for out-of-office business transactions and presentations, or working overseas. From
 the interviews with some participants, the use of notebook computers was found to be handy and
 tidy, which enhanced the image of the professional or sales. Another major reason for using
 notebook computer was that it made traveling easier because of its small size and mobility both
 within and outside Hong Kong. These observations are further investigated and verified in the
 Phase 2 –Telephone and Field Survey.



         The results also suggested that employees working in small- and medium-size enterprises
 (SMEs) were more likely to be prescribed with notebook computers when compared with their
 large size company counterpart. This was because most of the SMEs had relatively limited
 workspaces in the office, they had larger preference to prescribe a notebook computer for their
 employees, which replaced their large size desktop computer, while large corporate did not seem
 to share the same concerns.



         The preliminary results indicated that there were relatively little concerns expressed by the
 participants on health-issues associated with utilization of notebook computers. One problem was
 that the participants were not sure whether the health problems experienced by the users were
 attributable to the use of notebook computers at work. All the participants interviewed did not
 reveal a single case of musculoskeletal disorders nor discomforts known to them associated with
 the use of notebook computers. However, the medical practitioners, who were also interviewed,
 expressed more concerns with notebook computers utilization.                      They anticipated that
 musculoskeletal disorders or at least discomforts would be fairly common among the notebook
 computer users. They further explained that the problems might be due to the design of notebook
 computers such as the non-detachable screen, narrow keyboard and /touch pad mouse. The
 research team therefore proposed to conduct assessments of the musculoskeletal pain/discomfort



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 and other health issues of the participants interviewed in the Field Test. It is anticipated that the
 information gathered are useful in terms of resolving the observed discrepancies between the
 medical practitioners and those of the industry.


         The results from the interviews indicated that there were difficulties with implementing the
 existing regulations on notebook computer users. The main problems rest on the differences
 between the set-up and operations of notebook and desktop computers.                     The participants
 expressed their concerns with the uncertainty and applicability of the existing risk assessment
 criteria to notebook computers.         Besides, they expressed the difficulties in assessors defining
 whether an employee would satisfy with the criteria for a DSE “user”. It is because most of the
 notebook computers are used intermittently, used without a fixed posture and workstation layout,
 and carried from place to place inside or outside the work place. The participants also revealed
 that notebook computers were used for functions similar to those of the desktop computers.
 These were different from the conventional usage of notebook computers such as displaying
 presentations and emailing. Notebook computers users reported using them for prolonged-typing
 tasks such as word processing. These issues are important and to be addressed in the latter part
 of this project, i.e. Field Survey and development recommendations for improving the
 occupational health of notebook computer users.




     Occupational Safety and Health Council                                                               19
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 STAGE 2A: TERRITORY WIDE TELEPHONE SURVEY ON UTILIZATION OF NOTEBOOK
                 COMPUTERS




 1.     Introduction



          A territory-wide Telephone Survey was conducted to identify the prevalence of utilization
 of notebook computers among the population of Hong Kong. In this phase of study, there were
 two target groups, i.e. school-age teenagers (i.e. 12-18 years old) and working adults (i.e. 19-65
 years old or above). The potential occupational safety and health risks associated with utilization
 of notebook computers between these groups of respondents were studied.




 2.     Method



 Computer Prevalence Questionnaire
          The Telephone Survey conducted was based on a custom-designed 30-items questionnaire.
 Each interview took five to seven minutes to complete. The items covered socio-demographics
 information including occupation, gender, age, education levels and working status. It also
 covered preference and facts on utilization of the computers, i.e. type of computer use, duration,
 place of utilization, and utilization of external devices. There were items covering health and
 occupational safety concerns, i.e. areas of discomfort, utilization of ergonomics products, and
 training etc. Several panel reviews were conducted to establish evidence on the content validity
 of the items.




      Occupational Safety and Health Council                                                              20
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Respondents
          Three sampling frames, i.e. school-age children (i.e. 12-18 years old) and adult workers
 (i.e. 19-65 years old or above), locations (outdoor and indoor) and tasks involved (play or leisure,
 studying or work) were used and the sampling size was set at about 1,000 with about 500
 respondents were expected in each of the two sample groups. The Telephone Survey was
 conducted by Public Governance Program, Lingnan University between 19 and 29 November,
 2007. The respondents were selected with a two-stage random sampling method so as to ensure
 representative of the samples. The first stage of random sampling began with using the Chinese
 computer-aided-telephone interviewing (CATI) system to automatically generate phone samples
 based on the Hong Kong Telephone Directory. The last two digits of the selected telephone
 numbers were replaced by two random numbers. The second stage of random sampling involved
 the selection of the eligible samples belonging to household telephone numbers. The eligible
 samples of numbers were pooled and based on which the respondents were randomly drawn for
 conducting the telephone interview. About 70% of the phone calls were made during nighttime,
 and 30% during the daytime.



 3.     Results

 Response Rate
          A total of 20,665 calls were made, in which 2,577 were effective calls and 1,020
 respondents obtained, in which 503 school-age children (49.3%) and 517 working adults (50.7%)
 completed the interviewed. The average response rate was 39.6% with 42.5% from the school-
 age children and 37.3% from the working adults.

 Demographic Characteristics of Respondents
          Similar proportions of male and female (i.e. 49.3% and 50.7% respectively) from both age
 groups were interviewed. They had secondary or above education levels, and mostly lived in the
 New Territories (i.e. 50.9%). The detail characteristics of the respondents were summarized in
 Table 3 and Chart 3. Among the working adults (50.7%), they came from diverse occupational
 industries with the most from banking, finance, insurance, real estate and business services
 industry (19.9%). Second to this were the community, social and personal services industry (17%)



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 and import and export (7%), and transport, storage and communication industries (7%). The
 “other” category (22.2%) was composed of workers who were self-employed or could not
 classify themselves under a specific industry category.

              Table 3 Summary of Demographic Characteristics of the Respondents

   (N=1,020)                                  %               (N=1,020)                                          %
   Age (Yr)                                                     School-age Children (n=503)                     49.3
       12-14                                  16.3              Working Adult (n=517)                           50.7
       15-18                                  27.6
       20-24                                  15.1            Industry (n=517)
       25-29                                   7.2              Banking & Finance,                              19.9
       30-34                                   8.5                 Insurance, Real Estate &
       35-39                                   7.0                 Business Services
       40-44                                   8.6              Community, Social and                             17
       45-49                                   3.9                 Personal Services
       50-54                                   2.9              Import & Export                                  7.0
       55-59                                   0.9              Transport, Storage and                           7.0
       60-64                                   0.5                 Communication
       >65                                     0.1              Construction                                     5.8
       No response                             1.4              Retail                                           5.2
   Gender                                                       Manufacturing                                    4.4
       Male                                   49.3              Restaurant                                       2.1
       Female                                 50.7              Hotel & Boarding House                           1.4
   Education                                                    Electricity, Gas & Water                         0.6
       Tertiary                               30.9              Wholesale                                        0.4
       Secondary                              65.5              Agriculture & Fishing                            0.4
       Primary/No formal Education             2.7              Others                                           22.2
       Other                                   0.5              No Response                                      6.6
       No Response                             0.4
   Living (District)
       Hong Kong Island                       18.0
       Kowloon                                29.2
       New Territories                        50.9
       Islands                                 1.1
       No Response                             0.8

                             Chart 3                                 Banking & Finance, Insurance, Real Estate & Business Services
                                                                     Community, Social and Personal Services
                                                                     Import & Export
                                                                     Transport, Storage and Communication
                                                                     Construction
                                                                     Retail
                                                                     Manufacturing
                                                     Male
                                                                     Restaurant
                                                     Female          Hotel & Boarding House
                                                                     Electricity, Gas & Water
                                                                     Wholesale
                                                                     Agriculture & Fishing
                                                                     Others
                                                                     No Response



     Occupational Safety and Health Council                                                                                 22
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Preference of Types of Computers
         In total, there were 74.6% of the respondents using desktop computers only while 10.8%
 using notebook computers only (Table 4 and Chart 4). The rest of the respondents (14.6%) used
 both computer types. Among them, 83.5% of the school-age children and 66% of the working
 adults used desktop computer only at home or at work, while there were comparatively low
 utilization of notebook computers only, i.e. only 8.3% of the school-age children and 13.2% of
 the working adults using notebook computers. The proportions of respondents using notebook
 computers in both age groups were largely comparable. There were 20.8% of the working adults
 and 8.2% of the school-age children using both computer types.



    Table 4 Percentages of Respondents Utilizing Desktop or Notebook Computers, or Both

                         Prevalence of Computer Types (N=1020)                  %
                         Both Notebook and Desktop Computer
                             Working Adult                                      20.8
                             School-age Children                                  8.2
                             Both groups                                     14.6
                         Notebook Computer Only
                             Working Adult                                      13.2
                             School-age Children                                  8.3
                             Both groups                                     10.8
                         Desktop Computer Only
                             Working Adult                                      66.0
                             School-age Children                                83.5
                             Both groups                                      74.6

                  Chart 4
                                90
                                80
                                 70
                                 60
                                 50
                                 40
                                 30
                                 20
                                                                           Both Notebook and Desktop Computer
                                 10
                                                                           Desktop Computer Only
                                   0
                                                                           Notebook Computer Only
                                       Working
                                               School-age
                                        Adult            Both groups
                                                Children


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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Duration of Utilizing Computer
         A total of 94.7% of the respondents (i.e. 96.5% and 92.8% of working adult and school-
 age children respectively) reported using either types of computer for more than two years (Table
 5). The working adults (41.6%) mostly used computers for longer duration, i.e. more than 6
 hours/day while the school-age children (45.3%) mostly used only for 1-2.9 hours/day, and 33.2%
 of the school-age children used them for longer duration, i.e. 3-5.9 hours.                 No significant
 differences in the years and duration of utilization were revealed between notebook and desktop
 computer in both the adult and children groups.


          Table 5 Duration of Utilizing Different Types of Computers for Both Groups

    Years of Computer Utilization              %          Years of Computer Utilization            %
    of the School-age Children                            of the Working Adults
    > 1 Year                                  1.6         > 1 Year                               1.4
            Notebook Computer                       1.7           Notebook Computer                    0.8
            Desktop Computer                        1.6           Desktop Computer                     1.6
    1 – 1.9 Year                              5.4         1 – 1.9 Year                           1.7
            Notebook Computer                    5.1              Notebook Computer                 0.8
            Desktop Computer                     5.4              Desktop Computer                  2.1
    > 2 Years                                 92.8        > 2 Years                              96.5
            Notebook Computer                   93.2              Notebook Computer                98.5
            Desktop Computer                    92.8              Desktop Computer                 95.9


    Duration of Computer                        %         Duration of Computer                     %
    Utilization of the School-age                         Utilization of the Working
    Children                                              Adults
    < 1 Hour                                  10.5        < 1 Hour                              6.0
            Notebook Computer                    3.4              Notebook Computer                 3.1
            Desktop Computer                   11.5               Desktop Computer                  7.0
    1 - 2.9 Hours                             45.3        1 - 2.9 Hours                         24.2
            Notebook Computer                  49.2               Notebook Computer               22.1
            Desktop Computer                   44.8               Desktop Computer                24.9
    3 – 5.9 Hours                             33.2        3 – 5.9 Hours                         27.9
            Notebook Computer                  32.2               Notebook Computer               22.9
            Desktop Computer                   33.3               Desktop Computer                29.5
    > 6 Hours                                 10.3        > 6 Hours                             41.6
            Notebook Computer                  13.6               Notebook Computer               51.1
            Desktop Computer                     9.9              Desktop Computer                38.4




     Occupational Safety and Health Council                                                                  24
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




 Purposes of Utilizing Computers among the Respondents
         In the survey questionnaire, the respondents were asked to describe the purposes of using
 either types of computer. The options of the purpose were: (1) Internet/ Web Browsing, (2)
 Word Processing, (3) Information searching, (4) Graphic, (5) Email or Web conferencing, (6)
 Data Entry, (7) Entertainment or Game, and (8) others.



         Among the working adults, they used notebook computer for a wide variety of functions.
 The results indicated those notebook computers were used for word processing (57.3%), web
 browsing (49.6%), email/ Internet conferencing (23.7%) (Table 6). The utilization pattern for
 notebook computers was found similar to that of the desktop computer users, i.e. web browsing
 (50.3%), word processing (49.5%), and information searching (20.2%) which were the most
 frequently performed functions (Table 6). The school-age children also used notebook computers
 mostly for word processing (47.5%), web browsing (42.4%) and entertainment (35.6%), which
 was also similar to those for desktop computer, i.e. web browsing (53.2%), entertainment (39.6%)
 and word processing (27%). These findings further substantiate the notion that the notebook
 computers are likely to be used for carrying out similar tasks as the use of the desktop computers
 instead of serving their original purpose which is mobile and handy when working outside office.



                     Table 6 Purposes of Utilizing Computers for Both Groups

  3 Main Functions of Computers                %        3 Main Functions of Computers               %
  of the School-age Children                            of the Working Adults
  Notebook Computer                                     Notebook Computer
       1. Word Processing                     47.5           1. Word Processing                    57.3
       2. Web Browsing                        42.4           2. Web Browsing                       49.6
       3. Entertainment                       35.6           3. Email/ Internet Conference         23.7
  Desktop Computer                                      Desktop Computer
       1. Web Browsing                        53.2           1. Web Browsing                       50.3
       2. Entertainment                       39.6           2. Word Processing                    49.5
       3. Word Processing                     27.0           3. Information Searching              20.2




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Perceived Environmental and Ergonomics Characteristics Associated with Computer Utilization
         The respondents were asked to rate on the awareness of proper workstation design and
 posture, and satisfaction with the environment/ ergonomic characteristics, e.g. illumination which
 interfered with their computer utilizations. Most of the respondents appeared to be aware of
 environment/ ergonomic characteristics and were satisfied with the illumination, workstation
 space, chair in use, and desktop layout (i.e. DSE devices placed in the front) (Table 7). However,
 there was comparatively low number of people aware of “always sit with good posture” when
 using either types of computer.



  Table 7 Proportion of Respondents on Awareness of Workstation Design and Posture, and
              Satisfaction with Environmental and Ergonomic Characteristics

  Environment and Ergonomics                      %        Environment and Ergonomics                          %
  Factors of the School-age Children                       Factors of the Working Adults
  Illumination                                  89.1       Illumination                                 90.5
          Notebook Computer                      93.2              Notebook Computer                      93.1
          Desktop Computer                       88.7              Desktop Computer                       89.9
  Workstation Space                             94.2       Workstation Space                            87.6
          Notebook Computer                      87.9              Notebook Computer                      85.5
          Desktop Computer                       95.3              Desktop Computer                       88.3
  Adjustable Chair                              61.6       Adjustable Chair                             73.9
          Notebook Computer                      76.3              Notebook Computer                      71.8
          Desktop Computer                       59.7              Desktop Computer                       74.6
  Sitting Posture                               17.9       Sitting Posture                              28.4
          Notebook Computer                      20.3              Notebook Computer                      26.7
          Desktop Computer                       17.6              Desktop Computer                       29.1
  Desktop Layout                                           Desktop Layout
  DSE devices placed on the same level          59.4       DSE devices placed on the same level         66.0
          Notebook Computer                      63.0              Notebook Computer                      79.4
          Desktop Computer                       60.1              Desktop Computer                       63.1
  DSE devices placed in front of user           89.7       DSE devices placed in front of user          84.9
          Notebook Computer                      84.5              Notebook Computer                      84.4
          Desktop Computer                       90.5              Desktop Computer                       86.0


         Among the school-age children, there was a good proportion of them who reported
 having satisfactory environment including illumination (89.1%), workstation space (94.2%) and
 workstation layout (89.7%). Comparing to the working adult respondents, there was slightly
 lower proportion of the school-age children reporting awareness of using adjustable chairs (61.6%)



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 and proper desktop layout (i.e. DSE devices placed on the same level) (59.4 %). The smallest
 proportion of the school-age children (17.9%) was found in having a proper sitting posture when
 using computers. No significant differences were revealed in all these items between the desktop
 and notebook computer users.



         Among the working adult respondents, similar proportions of responses were observed as
 the school-age children respondents. They were mostly satisfied with the illumination (90.5%),
 workstation space (87.6%) and DSE devices placed in front of user (84.9%). Similarly, there
 were a good proportions of the working adult respondents being aware of having adjustable chair
 (73.9%) and desktop layout (i.e. DSE devices placed on the same level) (66%). They showed
 lower awareness, however, on proper sitting posture (28.4%).                 There were no significant
 differences in the results on these items between the desktop and notebook computer users.



 Computer-related Health Concerns
         Both groups of respondents reported the commonest discomforts over the shoulders/neck,
 (11.5% and 24.4% for children and adults respectively), the eyes (11.9% and 12%), the wrist
 (3.4% and 15.1%), and the lower back (5.6% and 7%). The patterns of discomforts reporting by
 the respondents were found not significantly associated with the types of computers used. There
 was slightly higher proportion of the working adult respondents using notebook computer
 reported discomforts in the shoulders/neck (26%) than those using desktop computers (23.8%)
 (Table 8 and Chart 5). It is noteworthy that the respondents in both groups attributed the
 discomforts reported in the interview to the prolonged hours using the computers (43.6%) and
 improper sitting posture (35.4%). In another question for respondents from the working adult
 group, there were only 11.8% of them reported that they had attended occupational safety and
 health related training workshop, seminar or exhibition organized by their employers or
 themselves, or acquired OSH-related information from browsing Internet or the Occupational
 Safety and Health Council website (Table 9).




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



              Table 8 Regions of Bodily Discomfort Associated with Use of Computers
                                   Reported by the Respondents

  Health Characteristics of the                   %        Health Characteristics of the               %
  School-age Children                                      Working Adults
  Eyes Strain                                  11.9        Shoulders/ Neck Discomfort                24.4
         Notebook Computer                       13.6             Notebook Computer                   26.0
         Desktop Computer                        11.7             Desktop Computer                    23.8
  Shoulders/ Neck Discomfort                   11.5        Wrist Discomfort                          15.1
         Notebook Computer                       16.9             Notebook Computer                   14.5
         Desktop Computer                        10.8             Desktop Computer                    15.3
  Lower Back Discomfort                        5.6         Eyes Strain                               12.0
         Notebook Computer                       10.2             Notebook Computer                    9.2
         Desktop Computer                         5.0             Desktop Computer                    13.0
  Wrist Discomfort                             3.4         Lower Back Discomfort                     7.0
         Notebook Computer                        3.4             Notebook Computer                    5.3
         Desktop Computer                         3.4             Desktop Computer                     7.5
  Headache                                     2.2         Hand/ Fingers Discomfort                  3.7
         Notebook Computer                        3.4             Notebook Computer                    5.3
         Desktop Computer                         2.0             Desktop Computer                     3.1
  Hand/ Fingers Discomfort                     1.6         Headache                                  1.5
         Notebook Computer                        3.4             Notebook Computer                    1.5
         Desktop Computer                         1.4             Desktop Computer                     1.6
  Upper Back Discomfort                        1.0         Upper Back Discomfort                     1.2
         Notebook Computer                        1.7             Notebook Computer                    1.5
         Desktop Computer                         0.9             Desktop Computer                     1.0
  Lower Limbs Discomfort                       0.4         Lower Limbs Discomfort                    0.2
         Notebook Computer                        0.0             Notebook Computer                    0.0
         Desktop Computer                         0.5             Desktop Computer                     0.3


          Chart 5 Reported musculoskeletal discomforts by respondents between
                   notebook and desktop computer users
                                   MSDs in Each PC Type of Adult

      Lower Limbs Discomfort

        Upper Back Discomfort
                     Headache

      Hand/ Fingers Discomfort
        Lower Back Discomfort
                    Eye Strain

              Wrist Discomfort
     Shoulder/ Neck Discomfort

                             0         5              10              15             20     25           30
                                              Both Types   Notebook        Desktop




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                      Table 9 Perceived Factors Leading to Bodily Discomfort
                          Factors perceived leading to discomfort             %
                              Hours using computers                           43.6
                              Improper sitting posture                        35.4
                              Resting                                         6.1
                              Workstation Design                              4.3
                          Attending OSH-related training
                              Yes (Both Groups)                              8.6
                                     Working adults                           11.8
                                     School-age children                        5.4
                              No (Both Groups)                               91.4
                                     Working adults                           88.2
                                     School-age children                      94.6


 Preference of Purchase of Computers
         Most of the respondents considered hardware specifications and price of the computers as
 the first two priority in their purchase of either type of computers. However, the working adult
 group also considered the specification, functions and brand of computers; while there were
 16.7% of the school-age children purchased their computer with comparatively less emphases on
 these considerations (Table 10). It was surprising to find that there were only a small proportion
 of the respondents from both groups considering desktop space and outdoor use upon their
 purchase of the notebook computer (i.e. about 3% or less). There were also a few working adult
 respondents considered risk and ergonomics factors in their purchase as well. Thus, there seems
 no obvious determining attributes that lead to an absolute decision on purchasing a particular type
 of computer.



 Types of Computer Utilization in Different Industry
         As reported by the adult working group, the five most common industries of those who
 reported using notebook computers were: (1) Social, Community and Personal services (13.7%);
 (2) Finance, Insurance Real Estate and Business services (12.1%); (3) Import & Export (5.3%);
 (4) Logistic, Storage and Communication (4.7%); and (5) Wholesales and Retails (4.7%)
 industries.    On the contrary, the five most common industries of those who reported using
 desktop computers were: (1) Finance, Insurance Real Estate and Business services (9.6%); (2)
 Social, Community and Personal services (7.6%); (3) Logistic, Storage and Communication


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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 (3.3%); (4) Import & Export (3.1%); and (5) Construction (2.7%) (Table 11). This further
 suggested that the use of notebook versus desktop computers is industry-independent.



        Table 10 Preferences of Purchase of Computers by Respondents in Both Groups

Computer Purchase Preference of                 %          Computer Purchase Preference of                 %
School-age                                                 the Adults
Specification                                 63.8         Specification                                65.2
        Notebook Computer                       76.3               Notebook Computer                     70.2
        Desktop Computer                        62.2               Desktop Computer                      63.5
Price                                         38.0         Price                                        42.7
        Notebook Computer                       47.5               Notebook Computer                     37.4
        Desktop Computer                        36.7               Desktop Computer                      44.6
Never considered                              16.7         Function                                     11.4
        Notebook Computer                        5.1               Notebook Computer                     10.7
        Desktop Computer                        18.2               Desktop Computer                      11.7
Function                                      8.3          Brand                                        10.8
        Notebook Computer                        5.1               Notebook Computer                     13.0
        Desktop Computer                         8.8               Desktop Computer                      10.1
Appearance                                    8.0          Never considered                             9.3
        Notebook Computer                        7.5               Notebook Computer                      7.6
        Desktop Computer                         6.5               Desktop Computer                       9.8
Brand                                         8.0          Appearance                                   8.3
        Notebook Computer                        8.5               Notebook Computer                     10.7
        Desktop Computer                         7.9               Desktop Computer                       7.5
Trend                                         2.0          Desk Space                                   1.7
        Notebook Computer                        3.4               Notebook Computer                      2.3
        Desktop Computer                         1.8               Desktop Computer                       1.6
Desk Space                                    1.0          Need for outdoor use                         1.4
        Notebook Computer                        0.0               Notebook Computer                      3.1
        Desktop Computer                         1.1               Desktop Computer                       0.8
Discount                                      0.8          Trend                                        1.0
        Notebook Computer                        3.4               Notebook Computer                      1.5
        Desktop Computer                         0.5               Desktop Computer                       0.8
Need for outdoor use                          0.2          Potential risk & ergonomics factors          1.2
        Notebook Computer                        0.0               Notebook Computer                      2.3
        Desktop Computer                         0.2               Desktop Computer                       0.8
Potential risk & ergonomics factors           0            Discount                                     0.4
        Notebook Computer                        0.0               Notebook Computer                      0.8
        Desktop Computer                         0.0               Desktop Computer                       0.3




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



     Table 11 Proportion of Respondents Using Different Types of Computers in Different
                                        Industries

                 Types of PC across industry                                           %
                    Social, community and personal services
                           Notebook Users                                              13.7
                           Desktop Users                                               7.6
                    Finance, insurance, real estate and business services
                           Notebook Users                                              12.1
                           Desktop Users                                               9.6
                    Import & export
                           Notebook Users                                               5.3
                           Desktop Users                                                3.1
                    Logistic, storage and communication
                           Notebook Users                                               4.7
                           Desktop Users                                                3.3
                    Wholesale & retail
                           Notebook Users                                               4.7
                           Desktop Users                                                2.2
                    Constructions
                           Notebook Users                                               4.2
                           Desktop Users                                                2.7
                    Manufacturing
                           Notebook Users                                               2.1
                           Desktop Users                                                2.3



 Association between Demographic Factors and Musculoskeletal Discomforts
         Further analyses were conducted on studying the associations (i.e. statistical relationships)
 between various demographic factors with the occurrence of different musculoskeletal
 discomforts. First of all, there were significant associations revealed between the discomforts in
 the shoulders/neck and the age of the respondents (Chi-Sq(df=10): 22.844, p=.011) using
 notebook computers (Table 12). It suggested that there was higher proportion of respondents
 who were older (i.e. ~45% over 30 years old and 24% over 40 years old) reported having
 discomforts in the shoulders/neck region. The finding was consistent with those obtained from
 the Field Survey which is to be reported in the next section. No significant associations however
 were found between gender of the respondents using notebook computer and their bodily
 discomforts. These reflected that there might have some human factors, which might lead to
 musculoskeletal discomforts in notebook computer users. However, it was also essential to



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 identify other factors which also showed associations between various musculoskeletal
 discomforts and utilization of notebook computer.



         The daily duration of utilization was also found to be significantly associate with the
 discomforts in shoulders/neck (Chi-Sq(df=3): 11.454, p=.010). This was supported by the results
 that more than half of those (54.8%) who reported suffering from shoulders/neck discomforts
 used notebook computer for more than 6 hours per day (Table 12). On the contrary, there were
 much lower proportions of the respondents (<20%) using notebook computers for less than six
 hours per day reported shoulders/neck discomforts.                                               The number of years of utilization of
 notebook computers was found to significantly associate with the discomfort in lower back (Chi-
 Sq(df=2): 7.441, p=.024). The results indicated that more than 98% of those using notebook
 computers had two years or longer of experience using the computers.
                                Table 12
                                                                                              Duration       Year
                                                              Eyes            Chi-Sq          6.460        .685
                                 Musculoskeletal Discomfort




                                                                                  (p-value)         .091           .710
                                                              Shoulders/ Neck Chi-Sq          11.454       1.993
                                                                                  (p-value)         .010           .380
                                                              Upper Back      Chi-Sq          .275         .096
                                                                                  (p-value)         .965           .953
                                                              Lower Back      Chi-Sq          1.829        7.441
                                                                                  (p-value)         .609           .024
                                                              Wrist           Chi-Sq          5.009        3.537
                                                                                  (p-value)         .171           .171
                                                              Hand            Chi-Sq          .994         .298
                                                                                  (p-value)         .803           .861
                                                              Headache        Chi-Sq          .351         .121
                                                                                  (p-value)         .951           .941




         Those who used word processing more often were found to be more likely to report
 discomforts in the shoulders/neck region (Chi-Sq(df=1): 19.875, p<0.001). There were 57.6% of
 the respondents who used notebook computers for word processing reported shoulders/neck
 discomforts (Table 13). Comparing with other functions, there were fewer respondents reporting
 shoulders/neck discomforts when they used notebook computers for web browsing (38.7%),
 information searching (17.7%) or emailing (27.4%).




     Occupational Safety and Health Council                                                                                          32
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




     Table 13                                           Eyes          Shoulders/      Upper        Lower       Wrist          Hand        Headache
                                                                        Neck          Back         Back
                  Internet Browsing   Chi-Sq          .154           1.719         .718         1.266        1.119          .093          .405
                                          (p-value)           .695          .190         .397         .260           .290          .761           .524
                  Word Processing     Chi-Sq          .587           19.875        3.400        1.339        1.616          .077          .429
                                          (p-value)           .444          .000         .065         .247           .204          .782           .513
      Functions




                  Graphic & Animation Chi-Sq          .225           .752          .032         .124         .254           .098          .040
                                          (p-value)           .635          .386         .859         .725           .614          .754           .842
                  Data Entry          Chi-Sq          .041           .610          .197         .149         .104           .390          .248
                                          (p-value)           .840          .435         .657         .699           .747          .532           .619
                  Information Search Chi-Sq           2.763          .277          1.021        .451         .164           .190          1.261
                                          (p-value)           .096          .599         .312         .502           .686          .663           .261
                  Emailing            Chi-Sq          .251           .828          .008         2.535        1.136          .024          1.537
                                          (p-value)           .616          .363         .930         .111           .287          .877           .215




                   Not using external devices was found to associate with various bodily discomforts. Firstly,
 significant association was found between not using external monitor and the report of
 discomforts in the shoulders/neck (Chi-Sq(df=1): 4.356, p=.037), the upper back (Chi-Sq(df=1):
 7.681, p=.006), the wrist (Chi-Sq(df=1): 7.253, p=.007) and the hand (Chi-Sq(df=1): 9.330,
 p=.002) (Table 14). The use of external monitor would enable users to adjust the height and
 distance of the screen, whilst notebook computers could not be adjusted to suit the notebook
 users and enhanced the working posture. The results showed that there were larger proportions
 of respondents, when external monitor was not connected to the notebook computers, reported
 discomforts in the shoulders/neck (93.5%), the upper back (75%), the wrist (89.7%), and the
 hand (83.3%).



                   Similar effects were also observed in those respondents who did not use external keyboard
 and mouse. There were associations between not using external keyboard and discomforts in the
 upper back (Chi-Sq(df=1): 4.891, p=.027) and the wrist (Chi-Sq(df=1): 15.751, p<.001); and not
 using external mouse and discomforts in the shoulders/neck (Chi-Sq(df=1):4.163, p=.041) and the
 wrist (Chi-Sq(df=1):4.262, p=.039); and not using external storage devices, e.g. USB and hard
 disk, and discomforts in the upper back (Chi-Sq(df=1): 8.489, p=.004) (Table 14).                                                                 These
 revealed that most of those who suffered from the musculoskeletal discomforts had not used
 external devices, i.e. keyboard, mouse or storage devices with their notebook computers. For




     Occupational Safety and Health Council                                                                                                              33
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 instance, among those who reported shoulders/neck discomfort, 97.8% did not use external
 monitor and 89.1% did not use external mouse in their operation with notebook computer.



     Table 14                                   Eyes         Shoulders/      Upper        Lower       Wrist           Hand         Headache
                                                               Neck          Back         Back
          External Monitor    Chi-Sq          .144          4.356         7.681        .951         7.253           9.330          .142
                                  (p-value)          .705          .037         .006         .329            .007           .002          .707
          External Keyboard   Chi-Sq          .000          .210          4.891        .338         15.751          .678           .205
      External
      Devices




                                  (p-value)          .997          .647         .027         .561            .000           .410          .651
          External Mouse      Chi-Sq          .282          4.163         .011         .137         4.262           .797           .022
                                  (p-value)          .595          .041         .915         .712            .039           .372          .881
          Storage Devices     Chi-Sq          .050          1.630         8.489        2.433        2.821           1.226          .497
                                  (p-value)          .822          .202         .004         .119            .093           .268          .481




            Finally, from the analysis, it indicated that there were significant associations between not
 attending OSH related workshop or not acquiring OSH related knowledge and onset of the
 shoulders/neck (Chi-sq(df=1): 14.491, p<.001) and the wrist (Chi-sq(df=1):4.960, p=.026)
 discomfort. Among those participants who had attended OSH related workshop or acquired
 OSH related knowledge, there were comparatively fewer number of participants complaining
 bodily discomforts, i.e. suffering from shoulders/neck and wrist discomforts.



 4. Discussion

            The results suggested that the proportions of respondents using notebook computers were
 small, 8.3% of the school-age children and 13.2% of the working adults. Desktop computers
 when compared with notebook computers were still predominantly used by workers in the
 industries. The design of this study and the lack of the past studies did not allow us predict the
 trend of using notebook computers between the working adults and school-age children in the
 future. As more and more school-age children learn about computers and use them in schools, we
 would anticipate increasing trends in the population (both school-age children and working adults)
 of using notebook computers or both desktop and notebook computers in the future years. It
 would be beneficial for conducting a follow-up study for example three years from now in order
 to confirm these trends. Because of the relatively small proportion and hence small sample sizes
 of notebook computer users yielded from this study, the interpretations of its results should be
 cautious.


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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




         Findings from this phase of the study indicate that computers, disregarding the types, were
 used for similar purposes such as word processing, web browsing by both working adult and
 school-age children groups. These suggested that whether using notebook or desktop computers
 did not associate with age of the users and purposes of use. Interestingly, the determining factors
 of choosing to use notebook computers were found not to relate to the availability of working
 desktop space and need for mobility of the computer. Rather, according to the results, using a
 notebook computer or not tended to relate to pricing, promotional strategies of sales company,
 and development of computer technology specific to the type of computer.



         From the results of the survey, they revealed that the respondents, disregard the types of
 computers, reported discomforts mostly in the shoulders/neck, the eyes and the wrist and the
 lower back. There were a few factors which were identified to associate with the bodily
 discomforts reported by the respondents.           First, the duration of daily use and the years of
 notebook computer utilization were significantly associated with reported discomforts in the
 shoulders/neck and the lower back. The longer the duration of daily use and the more the years
 of utilization was, the higher the percentages of respondents reported experiencing discomforts.
 The musculoskeletal discomforts had a mechanical origin and were aggravated by the utilization
 of notebook computers. The results of the Survey indicated that notebook computers are mostly
 used for prolonged-typing tasks such as word processing. Accumulation of daily and hence yearly
 loads might strain the musculoskeletal system of respondents’ body resulting in discomforts.
 These discomforts could develop into pain and ultimately work-related musculoskeletal disorders.
 Nevertheless, the pain and disorders which were out of the scope of this study could draw no
 conclusion on this aspect. Besides the duration of utilization, the respondents’ reported that they
 tended to assume a strained posture and did not have much opportunity to access to information
 on occupational health and safety. These factors were likely to attribute to the musculoskeletal
 discomforts as reported by the respondents in the Telephone Survey. These factors were further
 measured and analyzed for their relationships with musculoskeletal discomforts in the next section.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         Second, musculoskeletal discomforts were found to associate with not using external
 devices or ergonomic peripheral devices. The results seemed to suggest that the use of devices
 such as external monitor, keyboard and mouse attached to the notebook computers could alleviate
 the problems with musculoskeletal discomforts.              There were smaller proportions of the
 respondents reported experiencing musculoskeletal discomforts when they used one or more than
 one type of these devices than those who did not use them. In particular, those who used external
 monitor and keyboard with the notebook computers would have lower proportion of reporting
 discomforts in the upper back and wrist. These further supported the benefit of using ergonomic
 devices together with notebook computers.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 STAGE 2B (PART 1): FIELD SURVEY ON UTILIZATION                 OF   NOTEBOOK COMPUTER           BY   ADULT
                          WORKERS




 1.     Introduction



          This part of the study was to further collect data on the utilization patterns and prevalence
 of OSH-related issues encountered by workers when using notebook computer at work. The
 issues could be revealed by collecting data on occupational safety and health when workers were
 using notebook computer in a naturalistic working environment.



          It was anticipated that the pattern of using notebook computer would be different between
 indoor and outdoor working environment. It was further anticipated that habits and preferences
 of using notebook computer would be different among different industries and sizes of company.
 To capture these characteristics, data from each participant involved both a structured survey
 interview and field assessments were collected.




 2.     Method


          This study adopted three sampling frames for selecting the participants. They were the
 occupational groups (N=5), company sizes (N=3) and utilization location (N=2). These sampling
 frames gave a total of 30 groups. If each group was composed of ten participants, the total
 sample size would be 300. In view of the fact that the information gathered could be saturated
 rather quickly and the limited resources available to the research team, with the consent of the
 OSHC, the target of data collection had been scaled down to 100 participants who would take
 part in the face-to-face interview and field assessment.             When it was confirmed that the
 information gathered had been saturated, the rest of the 200 participants were to be interviewed
 via Telephone/ Online Survey.


      Occupational Safety and Health Council                                                              37
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         The potential participants were first contacted by e-mail which contained a description on
 the project and a consent letter. A follow-up telephone call was made or the 2nd email was sent to
 confirm the potential participants had received the information. The third email was sent to the
 potential participants one week later to enquire whether they would accept the invitation of
 participating in the study.


         Three instruments were used to guide the face-to-face interview and field assessment.
 They were the worker’s demographic and notebook computer utilization questionnaire, symptoms
 checklist, and environment and occupational health assessments. The demographic and notebook
 computer utilization questionnaire gathered demographic characteristics, nature of job tasks, and
 patterns of utilizing notebook computers. This questionnaire took about 15 minutes to complete.
 The work-related symptoms checklist was to obtain information about physical symptoms,
 interventions required and impact on work and leisure activities. It had specific questions on
 physical symptoms related to use of notebook computers. This questionnaire took 15 minutes to
 complete. The environmental and occupational health assessments involved the use of gadgets
 such as laser meter and lux meter to measure different environment elements which would have
 impacts on the participants’ use of notebook computers.              Besides, the participant’s working
 postures and physical layout of the notebook computers were recorded by photos (for later
 experts review). The total time taken to complete this part of the assessments was 15 minutes.

         The research personnel arranged to conduct the field assessment with the participants who
 had agreed to participate. In the initial 30 minutes of the field visit, the participant completed the
 demographic and notebook computer utilization questionnaire.                  Upon completion of the
 demographic and notebook computer utilization questionnaire, the participants were requested to
 remain seated with their normal working posture with the use of the notebook computer.                 The
 research personnel then carried out the environmental and occupational health assessments. The
 research personnel used the abovementioned gadgets to measure the environmental and
 anthropometric data of the participants. At the same time, the research personnel made notes of
 additional observations of the participants, and the workstation of the participants were
 photographed. Finally, the participants were requested to complete the final questionnaire, which
 focuses on the work-related symptoms.



     Occupational Safety and Health Council                                                               38
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



          The data obtained from this stage enabled the research team to identify the issues
 associated with participants’ using notebook computers.              The results formed the basis for
 formulating recommendation for notebook users for the next stage of this project.



 3.     Results



 Response Rates

          One thousand and eight hundred invitations were sent through emails to companies or
 associations of different industries and a total of 160 visits were subsequently made to companies
 or associations of which the human resource departments had indicated willingness to participate
 in the study. There were 315 feedback obtained from the invitations (response rate = 17.5%).
 Among them, 104 participants (33%) met the selection criteria and agreed to participate in the
 interview and field assessments. The fairly low response rate is common to this type of the field
 test research and this reflected that there were relatively small proportion of employees and the
 fewer companies were using notebook computers (13.2% as revealed in stage 2a).



 Demographic Characteristics of Participants

          Among the 100 participants who completed the interviews and field assessments, there
 were more female (63%) than male (37%). About 68% of them were between 30 to 39 years old.
 The participants were employees at different ranks and levels, i.e. junior to senior levels of job
 position. More than half of these participants (n=62, 62%) took up senior positions in their
 companies. Their job positions ranked from junior clerk and general officer to assistant manager,
 supervisor or director. These results were consistent with those obtained in Stages 1 and 2a.
 There were higher proportions of participants (or respondents) who worked at senior ranks were
 prescribed with notebook computers. The participants come from diverse industries: (1) Banking,
 finance, insurance, real estate and commercial servicing (n=17, 17%), (2) Community, social and
 personal servicing (n=37, 37%), (3) Logistic, storage and communication (n=27, 27%), (4)
 Import and Export (n=15, 15%), and (5) Construction industry (n=4, 4%) (Table 14 and Chart 6).




      Occupational Safety and Health Council                                                              39
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                            Table 14 Demographic Details of Participants

   (N=100)                                    %             (N=100)                                                            %
   Gender                                                   Occupation/ Industry
       Male                                   37.0            Banking & Finance,                                             17.0
       Female                                 63.0              Insurance, Real Estate &
   Age (Yr)                                                     Business Services
       25-29                                   7.0            Community, Social and                                          37.0
       30-34                                  40.0              Personal Services
       35-39                                  28.0            Logistic, Storage and                                          27.0
        40-44                                 15.0              Communication
        45-49                                  2.0            Import & Export                                                15.0
        50-54                                  8.0            Construction                                                    4.0
   Education
       Tertiary                               84.0
       Secondary                              12.0     Chart 6
       Primary/No formal Education             4.0
   Living (District)
       Hong Kong Island                       36.0
       Kowloon                                34.0
       New Territories                        28.0
       Islands                                 2.0                   Banking & Finance, Insurance, Real Estate & Business Services
                                                                     Community, Social and Personal Services
                                                                     Import & Export
                                                                     Logistic, Storage and Communication
                                                                     Construction




     Occupational Safety and Health Council                                                                                          40
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Notebook Utilization Pattern of Participants
         Most of the participants (n=87, 87%) reported that they had used notebook computers for
 more than two years in their daily works.             According to the definition stipulated by the
 Occupational Safety Health (Display Screen Equipment) Regulation, only 23% of the participants
 were not considered as “DSE User” whilst a large proportion (n=41, 41%) of the participants
 might fit to be considered as Users, i.e. they used notebook computers accumulatively for six
 hours or more in a day (Table 15 and Chart 7). These findings were found consistent with those
 revealed from the Telephone Survey that most of the notebook computers had had more than two
 years’ of utilization and used notebook computers for six hours or more in a day.



         There were 73% (n=73) reported using computers outside of the offices. These included
 65% using the computers at home, 23% at office of clients, and 24% at restaurant or other
 outdoor premises. There were another 16 % using notebook computers on the street or public
 transport (Table 16 and Chart 8). These findings concurred with those obtained from the panel
 review conducted in Stage 1.



         When they were asked the reasons of using notebook computers at work, the majority of
 the participants (66%) opined that it was because of their company’s decision of the purchase,
 whilst only about one-third (34%) explained that it fitted the requirements for outdoor utilization
 (Table 17 and Chart 9). Other reasons for purchasing notebook computers for use included better
 performance (32%) and more competitiveness of the price (23%) than those of desktop
 computers. When the participants were asked to make a free choice of the type of computers to
 use at work, interestingly, there were more participants who preferred notebook (i.e. 61%) than
 desktop computers (39%).




     Occupational Safety and Health Council                                                               41
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                       Table 15 Notebook Utilization Patterns of Participants

 (N=100)                                  %                                                           Chart 7 Daily hour use
                                                                                             每日使用量(小時)
 Year of Utilization
   <1                                   11.0       30
   1 – 1.9                               2.0
                                                   25
   >2                                   87.0
 Daily Utilization (Hour)                          20

   <2                                    5.0       15
   2 – 3.9                              18.0
   4 -5.9                               24.0       10

   6- 7.9                               15.0        5
   >8                                   26.0
                                                    0
   No response                          12.0                   <2             2 – 3.9        4 -5.9        6- 7.9        >8            No
                                                                                                                                     不回應
                                                                                                                                    Response




                     Table 16 Locations of Notebook Utilization of Participants

 (N=100)                                 %                                                                                Chart 8
 Necessity for Outdoor Use
   No                                   27.0               Transports
                                                          運輸工具上
   Yes                                  73.0
                                                            On Street
                                                                    街上
 Locations of Utilization
   Office                               100.0           Other Outdoor
                                                        其他室外地方
                                                               Places

   Home                                 65.0            Clients’ Office
                                                           客戶辦公室
   Office of Clients                    23.0                   Home
                                                                    住所
   Other Outdoor Premises               24.0                   Office
                                                               辦公室
   On Street                             8.0
                                                                          0    10       20    30      40   50       60   70   80        90     100
   On Transport                          8.0




     Occupational Safety and Health Council                                                                                        42
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                 Table 17 Preferences of Types of Computers by the Participants.

 (N=100)                                 %
 Preference                                                             Chart 9 Reselection of PC Type
                                                                                再選擇電腦種類
   Company Decision                     66.0
   Need for Outdoor Use                 34.0            70

   PC Performance                       32.0            60
   Price                                23.0
   Purpose of PC                        21.0            50

   Brand                                18.0            40
   Desktop Space                        6.0
   No Consideration                     4.0             30

   Potential Harm                       3.0             20
   Ergonomic & OSH                      3.0
   PC Appearance                        2.0             10

   Trend                                0.0             0
   Discount                             0.0                           手提電腦
                                                                Notebook Computer
                                                                                                    桌上型電腦
                                                                                               Desktop Computer
 Reselection of PC Type
   Notebook                             61.0
   Desktop                              39.0




         When the participants were asked on the functions of the notebook computer being
 utilized, there were higher percentages of respondents using notebook computer for work
 processing (74%), emailing (54.5%), and information search (52%) than other functions (2 to
 35%) (Table 18 and Chart 10). These were also consistent with the results revealed in Stage 2a
 and that notebook computers were reported as used for functions other than the conventional
 functions such as displaying presentations and emailing. This further explained the phenomenon
 that notebook computers would be used for a prolonged period of time because of involvement in
 typing-related tasks.




     Occupational Safety and Health Council                                                                 43
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                    Table 18 Preferences of Functions of the Notebook Computer

                               (N=100)                                        %
                               Functions
                                 Word Processing                             74.0
                                 Emailing                                    54.5
                                 Information Search                          52.0
                                 Internet Browsing                           35.0
                                 Data Entry                                  33.0
                                 Presentation                                33.0
                                 Graphic & Animation                          2.0
                                 Game                                          0


                   Chart 10 Functions of utilization


           80

           70

           60

           50

           40

           30

           20

           10

            0
                 Internet     Word       Graphic &   Data Entry   Presentation Information   Emailing
                Browsing    Processing   Animation                                Search



 Anthropometric Measurements of the Notebook Users

         Visit was paid and field assessment was conducted to each of the participants.
 Anthropometric measurements were conducted on the participant and the “workstation” on which
 the notebook computer was placed (refer to Pictures 1 and 2 for illustration).                         Measurement
 parameters included monitor height, desk height and keyboard heights. There were two sets of
 measurements:

         1) Parameters recorded when the participant assumed an actual working posture (defined
             as A); and



     Occupational Safety and Health Council                                                                      44
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         2) Parameters recorded when the participant was instructed to position in a proper
             position and posture according to ergonomic principles (defined as B).



         The proper position and posture of the participant was obtained by asking the participants
 to assume an upright posture sitting at a proper height with the level of the elbow at the level of
 the keyboard and mouse and keep about right angles at the hip, knee and elbow before taking
 measurements. The worker-workstation match results are defined as the discrepancy between the
 measurements obtained from the proper position and posture and those from the actual position
 (i.e. B – A) (see figures in Table 19).



            Picture 1 Anthropometric Measurements conducted in Field Assessment.




           Monitor height                        Desk height                       Keyboard height




              Eye level                          Elbow level                       Ideal seat height



         According to the results, the average actual monitor height of notebook computer used by
 the participants were 102.07cm (actual monitor height = distance from floor to the top edge of
 screen) (Table 19). The majority of the participants (61%) were 101-105cm. The average proper
 eye level of the participants (equivalent to proper monitor height = distance from floor to eyes of
 participants when sitting in a neutral and upright position on an office chair) was 112.46cm. The


     Occupational Safety and Health Council                                                               45
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 mean worker-workstation monitor height mismatch, i.e. discrepancy between the proper and
 actual monitor height, was 14.72cm (Min=1.5cm; Max=29cm). Majority of the participants were
 found to fall within the monitor height mismatch of 10-14cm (22%) and 15-19cm (34%) in
 particularly of 14cm (8%), 17cm (6%), and 19cm (9%). What the results indicated were that in
 general the monitor height of the notebook computer was in a much lower position than the eye
 level of the participants, which could contribute to the musculoskeletal discomforts of these
 participants (to be discussed in later sections).



         Apart from the monitor height, the desk and the seat heights are also important factors
 contributing to the occupational health of the participants. The average actual desk height (actual
 desk height = distance from floor to top of the desktop) of the participants using notebook
 computer was measured as 74.61cm (Min=68.5cm, Max=77.2cm). The most common desktops
 seen in the field assessments had the heights of 74cm (17%) and 75cm (37%). The average proper
 desk height (distance from floor to the height of the elbow in a right angled position of the
 participants when sitting in a neutral and upright position with both feet flat on the floor surface)
 was 68.46cm (Min=59.8cm, Max=80cm). The mean worker-workstation desk height mismatch,
 i.e. discrepancy between the proper and actual desk height, was 6.17cm (Max=16cm). As desktop
 height is usually non-adjustable, majority of the participants henceforth would need to raise the
 seat height by 5-9cm (54%). After raising the seat height, a footrest probable would be needed to
 compensate for the discrepancies to ensure that workers’ feet can be placed flat on a stable
 surface. This is particularly relevant to those who use notebook computer in an office
 environment. On the same token, the heights of the keyboard and mouse were found to relatively
 too high for the participants. The average actual keyboard and mouse heights (distances from
 floor to the level of the keyboard and mouse placed on the desktop) were 76.28cm and 73.91cm
 respectively. When compared with the average proper elbow height which was 68.46cm, the
 mean worker-workstation keyboard and mouse height mismatches were 7.82cm and 5.45cm.
 These indicated that the participants were in general working with keyboards and mouse which
 were placed at an excessively high level. Besides, the average actual viewing distance of the
 participants was measured as 62.97cm (Min=35cm, Max=90cm) and most of the participants




     Occupational Safety and Health Council                                                               46
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 (59%) was found to sit in a slightly farther distance than the recommended viewing distance, i.e.
 35 to 60cm.



        Table 19 Summary of Anthropometric Measurements and Worker-Workstation
                            Mismatches (Proper minus Actual)

                                                  Min.         Max.        Mean           SD
                                        Actual Measurements (A)
            Monitor Height                           93.00      108.00       102.07          3.46
            Desk Height                              68.50       77.20        74.61          1.40
            Keyboard Height                          65.00       81.00        76.28          4.49
            Mouse Height                             60.00       77.20        73.91          3.56
            Seat Heights                             41.10       54.00        48.21          3.15
            Eye Distance                             35.00       90.00        62.97          12.3
                                        Proper Measurements (B)
            Seat Height                              40.50       50.00        44.97          2.36
            Eye Level                               102.00      125.00       112.46          4.87
            Elbow Height                             59.80       80.00        68.46          3.96
                                       Recommended Adjustments
             Seat Height Adjustment or
             Recommended Foot Rest               0.00      16.00       6.17       3.94
             Height
             Monitor Height Adjustment            1.5      29.00      14.72       6.80
            Note: Max.=Maximum, Min.=Minimum, SD=standard deviation; unit is in centimeter;
            Worker-workstation match are defined as the discrepancy between the measurements
            obtained from the proper position and posture and those from the actual position (i.e.
            B – A)



         The worker-workstation mismatches would lead to excessive bending of the neck and
 elevation of the shoulders (see Pictures 2 and 3). When participants assumed a lower than proper
 sitting position (i.e. the elbow height was much lower than the desktop height), the most affected
 would be elevation of the shoulders when using the keyboard and/or mouse. Lower than a proper
 sitting height would require accommodations in the elbow (more extended) and the wrist joints
 (more bending). Other problems would include limited desktop space, inadequate wrist support




     Occupational Safety and Health Council                                                               47
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 and notebook computers not placing in front of the participants. All these would pose risks on the
 occupational health of users of notebook computers.



           Pictures 2 Sampled participants’ postures when using notebook computers




     Mismatches in height of monitor and eye level       Compact keyboard design resulting in unfavorable
                                                                       wrist joint angles




       Mismatches in desktop and elbow heights                         Very limited desk space




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                Pictures 3 Common Workstation Layout with Notebook Computer




      Notebook computer positioned on a                  Notebook computer positioned on side table
    computer rack with limited work space




  Notebook computer positioned close to edge            Notebook computer positioned on the corner
     of table with insufficient wrist space                          of work desk




   Notebook computer positioned in front of               Notebook computer positioned in front of
                 the user                                               the user




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         The field assessments also measured the illumination level of the environment in which
 notebook computers were used by the participants. The results of illumination revealed that the
 average light intensity on the desktop was 709.6 LUX, which was above the recommended levels
 of 300-500 LUX (Table 20). There were only one-fourth of the workstations (25%) illuminated
 at the level commensurate with the recommended levels. Higher proportion of workstations (69%)
 was higher than recommended levels. The light intensity measured on the keyboard (Mean=596.7
 LUX) and monitor (Mean=416.4 LUX) fell within the recommended levels.


            Table 20 Measurement of Light Intensity on Desktop of the Workstations

                                                      Minimum Maximum              Mean          SD
    Light intensity on the Desktop (LUX)                   249.00     1507.00         709.6       327.22
    Light intensity on Keyboard (LUX)                      185.00     1193.00        596.68       297.64
    Light intensity on Monitor (LUX)                       133.00      815.00        416.40       177.15



 Use of Ergonomic Features and Participants’ Discomforts
         The field assessment covered the type of ergonomic features which the participants
 adopted when using notebook computers.              Among the 100 participants, none of them was
 observed using a footrest or document holder at their workstation (Table 21 and Chart 11). From
 the results, no significant associations were found between not using external monitor and mouse,
 and no different MSDs were reported by the participants. However, significant associations were
 revealed between not using external keyboard and the discomforts in the shoulders/neck (Chi-
 Sq(df=1): 4.150, p=.042), in which 70% of the respondents reported suffering from
 shoulders/neck discomfort did not use an external keyboard; while the results obtained in the
 Telephone Survey which also showed the use of external keyboard was associated with lower
 chance of experiencing discomforts in the upper back and wrists. Significant associations were
 identified between not using external storage device and the discomforts in the lower back (Chi-
 Sq(df=1): 14.823, p<.001) and the hand (Chi-Sq(df=1): 8.734, p=.003) (Table 22). Only 8.9%
 and 26.7% of the participants reported experiencing discomforts in the lower back and hand when
 external storage devices were used. In order words, the participants who did not use these




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 devices together with notebook computers tended to have higher chances of experiencing
 discomforts over specific body parts.


      Table 21 Summary of Use of Ergonomics Features / Accessories by the Participants
                         Types of Ergonomics Devices / Accessories                                                 (%) (N=100)
                       Mouse (External)                                                                                92.0
                       Storage (External)                                                                              45.0
                       Keyboard (External)                                                                             40.0
                       Monitor (External)                                                                              26.0
                       Printer                                                                                         25.0
                       Adj Dock                                                                                        15.0
                       OSH Products                                                                                    13.0
                       Writing Pad                                                                                      7


                 Chart 11      100
                                90
                                80
                                70
                                60
                                50
                                40
                                30
                                20
                                10
                                 0
                                       Mouse     Storage Keyboard Monitor          Printer   Adj Dock     OSH      Writing
                                     (External) (External) (External) (External)                        Products    Pad




     Table 22                                        Eyes          Shoulders/         Upper          Lower           Wrist            Hand         Headache
                                                                     Neck             Back           Back
          External Monitor    Chi-Sq             .208             2.606            3.259          .422             .599             .493           1.087
                                  (p-value)                .648          .106            .071            .516                .439           .482           .297
          External Keyboard   Chi-Sq             .667             4.150            .155           2.116            .032             1.307          2.062
      External
      Devices




                                  (p-value)                .414          .042            .693            .146                .857           .253           .151
          External Mouse      Chi-Sq             2.174            3.579            2.543          2.088            .068             1.535          .269
                                  (p-value)                .140          .059            .117            .148                .795           .215           .604
          Storage Devices     Chi-Sq             .040             .621             .285           14.823           .746             8.734          3.780
                                  (p-value)                .841          .431            .594            .000                .388           .003           .052




            When the participants were asked how they carried the notebook for work outside the
 office, 46% of them carried it with a handbag, 32% with backpack, 19% hand-held the machine,
 whilst 26% carried it with a single-side bag. Only a small proportion of the participants replied



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 that they used ergonomic accessories such as hand trolley (3%). There was significant association
 between the use of handbag for carrying notebook computer and discomforts over the lower back
 (Chi-Sq(df=2): 18.182, p<.001), the wrist (Chi-Sq(df=2): 6.609, p=.037), the eye (Chi-
 Sq(df=2):11.872, p=.003) and headache (Chi-Sq(df=2): 6.572, p=.037) (Table 23a). There were
 more people with abovementioned bodily discomforts when handbag was used for carrying the
 notebook computer. Despite there were significant associations between using handbag, and eye
 discomfort and headache, the explanations for the phenomena are out of the scope of this study.
 In contrary, significant associations were also found between not using backpack for carrying the
 notebook computer and discomfort in the lower back (Chi-Sq(df=2): 22.529, p<.001), i.e. fewer
 proportion of people (i.e. 22.2%) reporting low back discomfort when backpack was used. It
 was noteworthy that there were significant associations between the use of hand for carrying
 notebook computers and discomforts reported in the upper back (Chi-Sq(df=2): 6.998, p=.030),
 and the lower back (Chi-Sq(df=2): 22.215, p<.001), i.e. more people suffering from these
 discomfort if they carried notebook computer with hand. Not using single-side bag (26%) for
 carrying notebook computers was found associated with the discomforts in the lower back (Chi-
 Sq(df=2): 19.325, p<.001) and the wrist (Chi-Sq(df=2):12.562, p=.002); and not using hand
 trolley (3%) associated with discomforts in the upper (Chi-Sq(df=2):13.446, p=.001) and lower
 back (Chi-Sq(df=2):18.266, p<.001) (Table 23a). These indicated that there were fewer number
 of participants experiencing bodily discomforts when these two types of carrying bag were used.
 There were 13.5% and 15.4% of participants, who had used single-side bag, reported discomforts
 in the lower back and wrist respectively; and 16% and 18.7% of participants, who had used hand
 trolley, reported discomforts in the upper and lower back respectively.



     Table 23a                                              Eyes           Shoulders/      Upper        Lower         Wrist           Hand         Headache
                                                                             Neck          Back          Back
                         Handbag          Chi-Sq          11.872          5.661         3.017         18.182        6.609           .957           6.572
      Carrying Methods




                                              (p-value)            .003          .059          .221          .000            .037           .620           .037
                         Backpack         Chi-Sq          .655            .559          4.086         22.529        4.174           1.927          3.631
                                              (p-value)            .721          .756          .130          .000            .124           .382           .163
                         Hand Carry       Chi-Sq          1.079           3.084         6.998         22.215        .248            .788           2.149
                                              (p-value)            .583          .214          .030          .000            .884           .674           .341
                         Single-          Chi-Sq          .336            4.749         1.921         19.325        12.562          .974           2.855
                         side/Messenger       (p-value)            .845          .093          .383          .000            .002           .615           .240
                         Hand Trolley     Chi-Sq          3.195           1.415         13.446        18.266        1.314           1.452          1.031
                                              (p-value)            .202          .493          .001          .000            .518           .484           .597




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Notebook-related Health Characteristics
         The common health or musculoskeletal problems reported by the participants are
 summarized in Table 23b and Chart 12.              The most common discomfort expressed by the
 participants was in the shoulders and neck regions (77%). Other areas of discomfort included the
 eyes (50%), the upper back (29%), the lower back and wrist (28% and 22%). It was also
 common to find participants reporting discomforts in multiple sites in the body. Only a small
 proportion of the participants expressed that they had sought medical consultation (i.e. 18%),
 whereas other 7% had sought consultations from Traditional Chinese Medicine or other
 alternative type of treatments such as bone-setter, acupuncture or reflexology. The participants
 self perceived that the causes of the bodily discomforts could be due to work (58%), lack of rest
 (26%), and natural degeneration because of aging (12%).

 Table 23b Bodily Discomforts Reported by Participants                                           Chart 12
      Locations of          Percentage of People       80
      Discomfort               Reported (%)            70
                                  N=100
                                                       60
 Shoulders and Neck                 77.0
                                                       50
 Eyes                               50.0
                                                       40
 Wrist                              29.0
                                                       30
 Lower Back                         28.0
                                                       20
 Upper Back                         22.0
 Hand                               15.0               10

 Headache                            3.0                0
                                                            Headache   Eyes   Shoulders/Neck Upper Back   Lower Back   Wrist   Hand        Lower Limb
 Lower Limb                          3.0


 Demographic Characteristics and Other Factors Related to Using Notebook Computers

 Gender and Age by duration of utilization
         From the Field Survey, the finding indicated that more male participants used notebook
 computers for shorter duration, i.e. 2 to 3.9 (27%) and 4 to 5.9 (24.3%) hours/day; while more
 female participants used notebook computers for longer hours per day, i.e. 4 to 5.9hr (23.8%), 6
 to 7.9hr (15.8%) and         > 8hr (38.1%).        There were relatively more participants working
 continuously up to 4-5.9 hour/day (24%) and accumulatively for more than 8 hours/day (26%).
 Besides, most of the participants working with notebook computer for 4-5.9 or >8 hours/day
 were those at age of 30-34.


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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




 Musculoskeletal Discomfort by Age and Gender
          Age of the participants was found to have significant association with the discomforts in
 the eyes (Chi-Sq(df=5): 24.9, p<0.001), the shoulders/neck (Chi-Sq(df=5): 19.288, p=.002) and
 the upper back (Chi-Sq(df=5): 23.299, p<0.001) (Table 24). There were more participants at the
 age of 30-34, 35-39 and 40-44 reporting discomforts in their eyes (15-17% versus 0-4%), the
 shoulders/neck (13-37% versus 0-6%) and the upper back (4-10% versus 0%) than those of the
 younger (i.e. 20-29) and older (45-54) groups. Gender was also found to associate with the
 discomforts in the shoulders/neck (Chi-Sq(df=1): 7.301, p=.007) and the wrist (Chi-Sq(df=1):
 14.250, p<.001). Female participants were more likely (85.7%) than the male (62.2%) reporting
 such discomforts. No significant associations were found between the gender and the discomforts
 in the other body parts. The discomforts in the shoulders/neck region (Chi-Sq(df=5): 23.844,
 p<0.001) and the hand (Chi-Sq(df=1): 12.472, p=.029) were revealed to significantly associate
 with the duration of using notebook computer. In general, the participants who reported using
 notebook computers for 4-5.9hr/day or >8hr/day (i.e. 28.6% and 30%) were more likely to report
 discomforts in the shoulders than those working for 2-3.9hr/day (15.6%) and 6 or 6-7.9hr/day
 (13%).
                          Table 24
                                                                                           Age           Gender          Duration
                                                        Eyes            Chi-Sq          24.90           1.073           6.943
                                                                            (p-value)            .000            .300         .225
                                                        Shoulders/ Neck Chi-Sq          19.288          7.301           23.844
                           Musculoskeletal Discomfort




                                                                            (p-value)            .002            .007         .000
                                                        Upper Back      Chi-Sq          23.299          .005            2.769
                                                                            (p-value)            .000            .944         .736
                                                        Lower Back      Chi-Sq          9.616           .394            12.596
                                                                            (p-value)            .087            .530         .027
                                                        Wrist           Chi-Sq          9.711           14.250          5.094
                                                                            (p-value)            .084            .000         .405
                                                        Hand            Chi-Sq          6.573           .102            12.472
                                                                            (p-value)            .254            .750         .029
                                                        Lower Limb      Chi-Sq          4.639           1.816           8.803
                                                                            (p-value)            .461            .178         .117
                                                        Headache        Chi-Sq          4.693           1.816           9.794
                                                                            (p-value)            .461            .178         .081




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



  Musculoskeletal Discomfort by Utilization Functions
                    The use of notebook computers for specific utilization was also found to associate with
  bodily discomforts. Browsing the Internet (35%) was significantly associated with the discomforts
  in the lower back (13%; Chi-sq(df=1): 5.024, p=.025), the wrist (15%; Chi-Sq(df=1): 5.022,
  p=.025;), the hand (10%; Chi-Sq(df=1): 7.778, p=.005;) and the lower limb (3%; Chi-Sq(df=1):
  5.744, p=.017) than those who did not (Table 25). Those who used notebook computer for word
  processing (74%) were more likely to report discomforts in the wrist (27%) (Chi-Sq(df=1):7.747,
  p=.005) than those who did not. Performing data entry was found to associate with discomforts
  in the lower back (Chi-Sq (df=1):10.252; p=.001) and the hand (Chi-Sq(df=1):8.692, p=.003), i.e.
  33% of participants, who had used notebook computer for data entry, reported discomfort in the
  lower back. Similarly, using notebook computer for information search was found to associate
  with discomforts in the eyes (Chi-Sq(df=1): 5.769, p=.016) and presentation with the wrist (Chi-
  Sq(df=1): 12.588, p<.001), i.e. 52% of participant, who had used notebook computer for
  information search, reported discomfort in the eyes. And there was no significant associations
  found with other utilization functions.



Table 25                                           Eyes          Shoulder/      Upper        Lower        Wrist           Hand            Lower     Headache
                                                                   Neck         Back         Back                                         Limb
             Internet Browsing   Chi-Sq          3.560          .224         .023         5.024         5.022           7.778          5.744        1.665
                                     (p-value)           .059         .636         .879          .025            .025           .005         .017           .197
             Word Processing     Chi-Sq          .208           .282         .496         .134          7.747           .493           1.087        1.087
                                     (p-value)           .648         .595         .481          .715            .005           .482         .297           .297
             Graphic & Animation Chi-Sq          2.041          .610         .576         .794          4.996           .360           .063         .063
 Functions




                                     (p-value)           .153         .435         .448          .373            .025           .548         .802           .802
             Data Entry          Chi-Sq          .045           3.291        1.979        10.252        .071            8.692          1.523        6.279
                                     (p-value)           .832         .070         .160          .001            .789           .003         .217           .012
             Presentation        Chi-Sq          2.216          1.713        .798         2.355         12.588          .001           1.523        1.523
                                     (p-value)           .137         .191         .372          .125            .000           .976         .217           .217
             Information Search Chi-Sq           5.769          3.548        2.959        1.183         3.239           .452           2.855        2.855
                                     (p-value)           .016         .060         .085          .277            .072           .501         .091           .091
             Emailing            Chi-Sq          2.576          1.513        1.946        .706          1.071           .003           3.631        3.631
                                     (p-value)           .108         .219         .163          .401            .301           .955         .057           .057




  Predicting Musculoskeletal Discomfort among the Participants
                    Age, gender, duration of utilization, locations of utilization, utilization functions, notebook
  carrying methods and types of external devices used were entered as predictor variables for
  conducting regression analysis. The outcome variable was the reported discomfort in one region
  such as shoulders/neck, or the eyes.


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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         Age of the participants was identified as a significant predictor of discomforts in the eyes
 (=44.7, p=.013) which accounted for 6% of the total variance. Duration of utilization was also a
 significant predictor of shoulders/neck discomforts (=-.466, p=.007) accounting for 7.1% of the
 total variance.     Using notebook computer for working at home (n=65 out of 100) was a
 significant predictor of discomfort in the eyes (=.992, p=.020; 5.2% of total variance). Similarly,
 using notebook computer for working at other outdoor places (n=24 out of 100) was also found
 to significantly predicting discomfort in the eyes (=1.152, p=.018; 5.5% of total variance),
 shoulders/neck (=1.435, p=.034; 4.4% of total variance), wrist (=1.003, p=.042; 4% of total
 variance) and upper back (=1.338, p=.011; 6.3% of total variance).

         Specific function of utilization was also found to be a predictor of particular bodily
 discomfort. Internet browsing (n=35 out of 100) was found to be a predictor of wrist discomfort
 (=1.005, p=.027; 4.8% of total variance), and lower back (=-1.19, p=.020; 5.3% of total
 variance), hand (=1.569, p=.006; 7.1% of total variance). Besides, word processing was found
 to be a predictor of wrist discomfort (=1.931, p=.002; 8.8% of total variance). PowerPoint
 presentation was a predictor of hand discomfort (=-2.348, p<.001; 13.9% of total variance.
 Information search predicted eyes discomfort (=.981, p=.016; 5.7% of total variance).

 Musculoskeletal Discomfort associated with Work Desk Dimensions
         The dimensions of the workstation, seating chair and other accessories were measured.
 Correlations were computed between these dimensions and the report of musculoskeletal
 discomforts in different parts of the body. The dimensions included monitor height (measured
 from floor to the top edge of monitor), desk height (measured from floor to the desk surface),
 original seat height (the distance between the seating surface and floor), and the seat adjustment
 height/ recommended foot rest height, eye distance (distance between eyes of participants and the
 top edge of the monitor of the notebook computer) and illuminations of the workstation
 environment. In the analyses, the eye level discrepancy (discrepancy between the top edge of
 monitor and appropriate eye level of participants), the eye distance discrepancy (deviation from
 the recommended level, i.e. 35-60cm) and elbow discrepancy (discrepancy between desk height
 and the appropriate elbow height of participants) were used.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Eyes Discomfort vs. Work Desk Dimensions
         The reported discomfort in the eyes were found to significant associate with the eye
 distance discrepancy (Chi-Sq(df=4): 9.615, p=.047), eye level discrepancy (Chi-Sq(df=5): 18.165,
 p=.003), and level of illuminations (Chi-Sq(df=6): 26.263, p<.001). In general, participants who
 had larger monitor height discrepancy (58%, 16 cm or more), and the lower (56%, <600 LUX) or
 higher (22%, >1000 LUX) level of illumination were more likely to report discomforts in the eyes.
 When these variables were entered into a regression equation for predicting discomforts in the
 eyes, the eye distance discrepancy (=.434, p=.006; 7.3% of total variance) was found to be the
 most significant predictor.



 Shoulders/Neck Discomfort vs. Work Desk Dimensions
         Significant associations were found between the eye distance (Chi-Sq(df=4):19.290,
 p=.001) and illumination discrepancy (Chi-Sq(df=6):20.646, p=.002) with the shoulders/neck
 discomfort. In other words, the larger the discrepancies in the eye distance (16.9%), and the
 illumination level below 500 LUX (29.9%) or above 1000 LUX (22.1%) were, the more likely the
 participants reported discomforts in the shoulders/neck discomfort (77% versus 23%).



 Upper Back Discomfort vs. Work Desk Dimensions
         Significant associations were found between the elbow discrepancy (Chi-Sq(df=3): 11.007,
 p=.012), eye level discrepancy (Chi-Sq(df=5): 13.954, p=.016) and illumination discrepancy (Chi-
 Sq(df=6): 12.712, p=.048) with the upper back discomfort. The larger the discrepancies in the
 elbow distance (i.e. >6cm) were, the more likely the participants experienced upper back
 discomfort (68.2% versus 31.7%).




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Lower Back Discomfort vs. Work Desk Dimensions
         The eye distance discrepancy (Chi-Sq(df=4): 14.241, p=.007), elbow discrepancy (Chi-
 Sq(df=3): 13.049, p=.005) and illumination (Chi-Sq(df=6): 18.061, p=.006) were significantly
 associated with participants’ report of lower back discomfort. The larger the discrepancies in the
 eye distance (32.1% versus 18.5%), the elbow distance (57%, >6cm versus 32%) and illumination
 (67.8%, below 600 LUX versus 31.2%) were, the higher was the proportion of participants
 reporting lower back discomfort was. The eye distance discrepancy (=-.401, p=.010; 6.5% of
 total variance) and eye level discrepancy (=-.550, p=.001; 9.9% of total variance) were identified
 as significant predictors of lower back discomfort.


 Wrist Discomfort vs. Work Desk Dimensions
         Significant associations were identified between the eye level discrepancy (Chi-Sq(df=5):
 32.160, p<0.001), illumination (Chi-Sq(df=6): 24.102, p=.001), and the discomforts in the wrist.
 The results showed that the larger the discrepancy in eye level was, e.g. >11cm, the higher the
 proportion of participants reported wrist discomfort (89.7% versus 11.3%) was. Besides, the
 larger the illumination discrepancy (48.3% versus 17.8%, less than 500 LUX; or 37.9% versus
 17.8%, larger than 1000 LUX) was, the more the proportion of participants reported wrist
 discomfort was. Among all the abovementioned factors, the eye level discrepancy (=-.414,
 p=.013; 6.0% of total variance) was found significantly predicting participants’ wrist discomfort.



 Hand Discomfort vs. Work Desk Dimensions
         Significant association was identified between the elbow discrepancy (Chi-Sq(df=3):
 10.563, p=.014) and the discomforts in the hand (52.1% versus 17.8%). The same variable was
 found to be the only significant predictor of hand discomforts.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 STAGE 2B (PART 2): TELEPHONE/ ONLINE SURVEY ON UTILIZATION OF NOTEBOOK
                       COMPUTER




 1.     Method



          The Telephone/ Online Survey was a supplement to the Field Survey. The purpose was to
 further build up the data base of using different methods. The intention of this part of the study
 therefore was not to gain new insights into the situation at hand but to improve the
 generalizability of the results. Data was collected through Telephone/ Online Survey.



          Questions for the potential participants to complete were extracted from the three
 instruments previously used in the Field Survey. The questions covered worker’s demographic,
 notebook computer utilization, and physical symptoms. There were two groups of potential
 participants: one group was recruited via phone calls and the other group was recruited via e-mail
 contacts. Both methods took the subjects about five minutes to complete the survey. For those
 who were contacted via e-mails, a direct internet hyperlink accessing to the online survey
 webpage was contained in the e-mail.




 2.     Results



 Demographic Characteristics of the Participants

          There were 200 participants completed the telephone (n=18) and online (n=182) surveys.
 Among them, there were more female (60.0%) than male (40.0%), which were similar to the
 results obtained in the Field Survey (Table 26). About 82.5% of them were between 25 and 39
 years old. They mostly carried job titles of legal executive, merchandiser, sales, health
 professionals and educator. The participants were from: (1) Community and social servicing



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 (n=70, 35%), (2) Banking, financial, insurance, real estate and commercial servicing (n=45,
 22.5%) and Manufacturing industry (n=45, 22.5%), (3) Import and Export (n=20, 10%), (4)
 Logistic, storage and communication (n=15, 7.5%), and, (5) Hospitality (n=5, 2.5%).



                            Table 26 Demographic Details of Participants
   (N=200)                                    %              (N=200)                                 %
   Gender                                                    Occupation/ Industry
       Male                                   40.0             Community, Social and                35.0
       Female                                 60.0               Personal Services
   Age (Yr)                                                    Banking & Finance,                   22.5
       20-24                                  10.0               Insurance, Real Estate &
       25-29                                  45.0               Business Services
       30-34                                  35.0             Manufacturing                        22.5
       35-39                                   2.5             Import & Export                      10.0
        40-44                                  5.0             Logistic, Storage and                 7.5
        45-49                                  0.0               Communication
        50-54                                  2.5             Hospitality                          2.5
   Education
       Tertiary                               90.0
       Secondary                               5.0
       Primary/No formal Education             5.0
   Living (District)
       Hong Kong Island                       22.5
       Kowloon                                30.0
       New Territories                        47.5



 Notebook Utilization Pattern of Participants
         Most of the participants (n=185, 92.5%) reported that they had used notebook computers
 for more than two years in their daily works. According to the definition stipulated by the local
 Occupational Safety Health (Display Screen Equipment) Regulation, only 7.5% of the participants
 might not be considered as DSE users whilst the remaining ones (n=185, 92.5%) might be
 regarded as DSE users with their daily utilization of notebook computers were either at least four
 hours continuously or more than 6 hours accumulatively (Table 27).




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                          Table 27 Years and Hours of Notebook Utilization
                                 (N=200)                                 %
                                 Year(s) of Utilization
                                   1 – 1.9                               7.5
                                   >2                                   92.5
                                 Daily Utilization (Hour)
                                   2 – 3.9                               7.5
                                   4 -5.9                               20.0
                                   6- 7.9                               37.5
                                   >8                                   35.0

         Different from the results obtained from Field Survey, only 30% (n=60) of the participants
 reported using computers outside of offices. Among them, 37.5% used the computers at home,
 7.5% at office of clients, and 12.5% at restaurant or other outdoor premises. There were another
 7.5 % using notebook computer on the street or public transport (Table 28).


                     Table 28 Locations of Notebook Utilization of Participants
                                 (N=200)                                 %
                                 Necessity for Outdoor Use
                                   No                                  70.0
                                   Yes                                 30.0
                                 Locations of Utilization
                                   Office                              97.5
                                   Home                                37.5
                                   Office of Clients                    7.5
                                   Other Outdoor Premises              12.5
                                   On Street                            2.5
                                   On Transport                         5.0




         When being asked why the participants were required to use notebook computers at work,
 the majority (40%) opined that it was because of their company’s decision of purchase, whilst less
 than one-third of them (27.5%) used notebook computers because they fitted the requirements for
 outdoor utilization (Table 29). When the participants were asked to make a free choice of the
 type of computers to use at work, interestingly, opposite result was shown when comparing with
 those of the Field Survey, i.e. there were more participants choosing desktop (i.e. 65%) instead of
 notebook computers (i.e. 35%).



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




                    Table 29 Preferences of Types of Computers of Participants

                                 (N=200)                                 %
                                 Preference
                                   Company Decision                    40.0
                                   Need for Outdoor Use                27.5
                                   PC Performance                      27.5
                                   Price                               45.0
                                   Purpose of PC                       22.5
                                   Brand                               25.0
                                   Desktop Space                       30.0
                                   No Consideration                    10.0
                                   PC Appearance                       10.0
                                   Potential Harm                       0.0
                                   Ergonomic & OSH                      0.0
                                   Trend                                0.0
                                 Reselection of PC Type
                                   Notebook                            35.0
                                   Desktop                             65.0




         When the participants were asked about the functions utilized, 85% reported using the
 computer for word processing, 72.5% for emailing, 65% for Internet browsing, and 60% for
 information search. These results were similar to those revealed from the Field Survey (Table 30),
 except there were more participants from the Telephone/Online Survey using notebook computer
 for Internet Browsing comparing to those obtained from the Field Survey (35%).




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



                    Table 30 Utilization of Computer Functions by Participants

                          (N=200)                            % (from        % (from
                                                             Tel/Online    Field Survey)
                                                              Survey)
                          Functions
                            Internet Browsing                  65.0           35.0
                            Word Processing                    85.0           74.0
                            Graphic & Animation                7.5             2.0
                            Data Entry                         32.5           33.0
                            Presentation                       20.0           33.0
                            Information Search                 60.0           52.0
                            Emailing                           72.5           54.5
                            Game                                10              0


 Use of Peripheral Device and other Ergonomics Accessories
         The results from the Field and Telephone/ Online Survey indicated that external mouse
 and external storage were used together with the notebook computer (Table 31). When the
 participants were asked how they carried the notebook for work outside the office, 25% of them
 carried it with a handbag, 7.5% with backpack, 10% hand-held the machine, whilst 10% carried it
 with a single-side bag. None of the participants used ergonomic accessories such as hand trolley.



        Table 31 Summary of Use of Ergonomics Features / Accessories by Participants
             Types of Ergonomics Devices / Accessories                 % (from             % (from Field
                                                                   Tel/Online Survey)         Survey)
           Mouse (External)                                               40.0                92.0
           Storage (External)                                             40.0                45.0
           Keyboard (External)                                            2.5                 40.0
           Monitor (External)                                             2.5                 26.0
           Printer                                                        32.5                25.0
           Adj Dock                                                       0.0                 15.0
           OSH Products                                                   2.5                 13.0
           Writing Pad                                                     0                   7




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Notebook-related Health Characteristics
          The most common discomforts expressed by the participants was discomfort in the
 shoulders and neck region (80%) (Table 32). Other areas of discomforts included the eyes
 (52.5%), the wrist (50.0%), and the lower back and upper back (both are 17.5%). The
 participants perceived that the causes of the bodily comfort could be due to work (40%), lack of
 rest (25%), and natural degeneration because of aging (5%).



                        Table 32 Bodily Discomforts Reported by Participants
             Locations of                        %                                %
              Discomfort              (from Tel/Online Survey)            (from Field Survey)
         Shoulders and Neck                     80.0                             77.0
         Eyes                                   52.5                             50.0
         Wrist                                  50.0                             29.0
         Upper Back                             17.5                             22.0
         Lower Back                             17.5                             28.0
         Headache                                7.5                              3.0
         Hand                                    5.0                             15.0
         Lower Limb                              5.0                              3.0




 3.     Discussion


          The results of this part of the study suggested significant relationships between gender and
 age, and the duration and functions of utilization of notebook computers by the participants. The
 data suggested that notebook computers are commonly used for functions similar to those using
 in desktop computers in the workplace. The duration of the participants using the notebook
 computers was relatively long such as longer than accumulatively six hours per day. In this case,
 the participants might be classified as the “Users” under the existing Occupational Safety and
 Health (Display Screen Equipment) Regulation. Significant associations were revealed between
 the duration of notebook utilization and the origins of discomforts reported by the participants in
 the shoulders/neck, lower back and hand. This further indicated the potential problems brought
 by using notebook computers for prolonged period of time. The fact that notebook computers



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 were designed for mobile and short duration use which was quite different from that of desktop
 computer, i.e. designed for stationary and prolonged duration use. This difference in usage
 should be highlighted to both users and employers. The discrepancies between the design of the
 notebook computers and their actual pattern of utilization by the participants were less desirable.
 The mismatches between the design and the use possibly attributed to the high frequency of
 reporting discomforts in the body parts such as the eyes, shoulders/neck, upper limb and wrists.
 More importantly, as reflected from findings of this study, the eye-, elbow- and illumination levels
 which the participants displayed did not commensurate with the common practices recommended
 in the health guides published by the Labour Department (i.e. Simple Guide to Health Risk
 Assessment, Office Environment Series – Lighting, 2003; Simple Guide to Health Risk
 Assessment, Office Environment Series –                Office Workstation Design, 2003) and the
 Occupational Safety and Health Council (i.e. Safety and Health Guides for Working with DSE,
 2004).    Previous studies have reported the close relationships between mismatches in these
 parameters and work-related disorders (e.g. Blehm et al., 2005, Jaschinski, 1999, Villanueva,
 Jonai & Saito, 1998; Saito et al., 1997; Ankrum, 1996).



          This study also revealed similar patterns of larger discrepancies associated with higher
 proportion of participants reporting discomforts in various parts of the body. The results revealed
 further indicated the needs to develop recommendations and best practices for notebook
 computer users in Hong Kong.



          In general, there were more female than male participants reporting using notebook
 computers in both the Field and Telephone/ Online Surveys (63% versus 37% and 60% versus
 40% respectively). There was also larger proportion of female participants reporting discomforts
 in their body parts. Besides, young to middle age participants (i.e. 30-39 years) were found to
 have the highest proportion among other age groups using notebook computers and at the same
 time reporting musculoskeletal discomforts over the eyes, shoulders/neck and upper back. Further
 studies therefore need to be conducted for explaining the phenomenon of female and 30-39 years
 of age participants getting a higher tendency to use notebook computers at work. Nevertheless, it



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 was obvious that the tendency of use was associated with the rate of reporting musculoskeletal
 discomforts. This again called for development of recommendations and best practices of using
 notebook computers in particular to address the needs of this group of users.



          Duration and function of utilizations were significantly associated with reports in
 musculoskeletal discomforts in the participants. The results suggested that the longer the hours of
 notebook utilization was, the higher the incidence of reporting shoulders/neck discomforts would
 be. These findings were consistent with those revealed in Leung et al. (2004) of which the results
 were obtained from using desktop computers. It was therefore important to incorporate rest
 breaks and regular exercise, and reinforce appropriate working posture in the recommendations
 and best practices to be developed in this report. To further tackle the issues on prolonged use of
 notebook computer at work, it was recommended that the provisions stipulated in the
 Occupational Safety and Health (Display Screen Equipment) Regulation should be further
 emphasized in the recommendations. As utilization patterns had not shown to associate with the
 type of industry, the needs on developing separate sets of recommendations and best practices for
 addressing industry-specific issues may not be necessary.



         It was noteworthy that notebook computers were reported to be equally utilized both
 inside and out of the office. Among the participants who reported using notebook computers out
 of the office (about two-third of the participants), over half of them (65%) reported that they
 were required to bring the computers back to their homes and use them in the Field Survey. This
 perhaps accounted for the prolonged hours of utilization, i.e. accumulatively longer than 6 hours
 per day. At the same time, as discussed in the previous paragraph, excessive use of notebook
 computers were found to relate to higher incidence of reporting musculoskeletal discomforts in
 the shoulders/neck, and upper and lower back. These findings had two implications. First, there
 are needs for developing a separate set of recommendations for using notebook computers both
 for inside and out of the office locations. The recommendations for using notebook computers
 inside the office can be applicable to the use at home. Second, as notebook computers are likely
 to be carried in- and out-offices, the recommendations to be developed will incorporate a manual
 material handling component.



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




         The results of the anthropometric measurements from the Field Survey revealed
 substantial worker-workstation mis-matches among the participants. The findings suggested that
 musculoskeletal discomforts as reported by the participants were associated with the extent of the
 deviations from the “appropriate” monitor and desk heights, eye distance and illuminations.
 In particularly, these mis-matches were found to associate with the discomforts in the
 shoulders/neck, wrist and lower back.           Our findings were consistent with other studies on
 occupational health issues brought by using desktop computers (e.g. Villanueva, et al., 1996;
 Turville, et al., 1998; Burgess-Limerick, et al., 1999). These mis-matches had been known to
 cause excessive strains on the neck, shoulders and upper limb in particular with the higher/lower
 monitor height than the eye-level. A closer look at the data revealed that the discrepancies mostly
 due to the chairs used by the participants were not adjustable (such as a chair in the restaurant or
 conference site) and the height of the desks on which the notebook computers placed were usually
 too high. The average elbow-keyboard height mismatch was about 6cm. With this discrepancy,
 the participants needed to either raise the chair by 6cm or lower the work surface by the same
 height. Besides the elbow-keyboard height mis-match, another common problem was the mis-
 match between the eye-monitor heights. In general, the mis-match was found to be around 14cm
 of which the monitor of the notebook computers was too low for the participants’ eye-level. As
 notebook computers do not usually come with an adjustable height monitor, it would be difficult
 for aligning the heights between the eyes and the monitor, and the heights between the elbow and
 the keyboard with the same desktop surface. This kind of work environment is highly undesirable
 for notebook computer utilization. The situation is detrimental when notebook computers are
 used as if desktop computers. The illustration of using different workstation designs and /or
 accessories will be incorporated in the new recommendations and best practices.



         Last but not least, the results obtained from the Telephone/ Online Survey were found to
 by and large consistent with those from the Field Survey. This further suggests that the data
 obtained in the Stage 2 study is largely valid.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 STAGE 3: RECOMMENDATIONS AND DEVELOPMENT OF HANDBOOK OF GOOD PRACTICES




 1. Introduction



         In this section, the research process with which recommendations and potential preventive
 measures to be considered by the Occupational Safety and Health Council or the employers of the
 companies with workers using notebook computers will be described. Development of
 recommendations and good practices will be based on the existing utilization patterns gathered in
 the previous two stages and the potential threats to occupational health of the workers. No
 attempt however will be put on investigating the effectiveness of different strategies for enhancing
 workers’ occupational health and use of notebook computers.




 2. Methods



         The research team adopted a qualitative and participative method to collect feedbacks
 from different panels on the recommendations and preventive measures derived from the results
 obtained in Stage 2. There were two panels. The first panel was composed of experts in
 occupational safety and health, and employers’ representatives (called the expert panel). This
 panel was responsible for generating options for good practices, and at the same time explored
 their feasibility, compliance and effectiveness.        The experts were those with experiences in
 ergonomics, occupational health, occupational medicine, physiotherapy and occupational therapy,
 optometry, engineering and representatives of various occupational groups. The second panel
 was composed of workers in different occupational groups (called the worker panel). These
 workers were those who were recruited and participated in Stage 2 – Field Survey. Their consents
 were obtained prior to the participation in this part of the study.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         The results obtained in the Stages 2a and 2b, and the existing Occupational Safety and
 Health Regulation on Manual Handling Operations and the Occupational Safety and Health
 (Display Screen Equipment) Regulation, and the guidelines published by Occupational Safety and
 Health Council and Labour Department were referenced to in the panel meetings. The guidelines
 and literature published outside of Hong Kong were also reviewed whenever necessary.



         All meetings of the expert panel were conducted before the worker panel. Face-to-face
 interview with experts (in group or individual) were held at the experts’ convenience (mostly at
 the workplace). Guiding questions were asked by the interviewers in the meeting whilst the
 experts’ responses were noted and summarized. The meetings lasted between 30 minutes and one
 hour. In the meeting, comments made by the experts were gathered and special attention was paid
 on those not covered under the existing Occupational Safety and Health (Display Screen
 Equipment) Regulation. After completing the meetings with the expert panel, members of the
 worker panel were interviewed. Similar to the format set for the expert panel, meetings were held
 in a group or individual basis.        The focus of interviewing with the work panel was on the
 feasibility of applying the proposed recommendations and good practices to the frontline work.
 Besides, members of the worker panel were asked to suggest changes if any on the proposed
 recommendations and good practices.



 3. Results



 Participants’ Characteristics
         Altogether, a total of 57 experts and employers’ representatives were contacted to join the
 expert panel. They were previously contacted and participated in Stage 1 of this study. The 100
 participants who had involved in the Stage 2b – Field Survey and the 200 participants who had
 participated in the Telephone/ Online Survey were contacted for joining the worker panel.
 Besides, those potential participants who had been previously invited for participation in this
 study but not successful were contacted for the second time. This was believed to further expand
 the sample pool in this part of the study.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




         A total of 33 participants were recruited for the expert panel and completed the interview.
 They came from very diverse backgrounds including information and computing technology,
 ergonomics, occupational health and safety, occupational medicine specialists, orthopedic and
 traumatology specialist, optometry occupational therapy, physiotherapy and prosthetics and
 orthotics.   The final sample of participants in the worker group were from the participants
 involved in stages 2a and 2b, and some had not involve in any stage, and 82 participants were
 interviewed. Most of them (85%) were those who had involved in the Field Survey and the
 Telephone/ Online Survey. They were the workers from the finance, insurance, real estate and
 business services, social, community and personal services, logistic, storage and communication
 services, constructions, and import and export industries, and some were self-employed (2%). In
 total, the 82 interviews conducted reached a saturation, i.e. no new or additional information or
 opinions were given by the new interviewees, and the interview henceforth was terminated.



 Classification of Utilization Patterns
         In general, the utilization of notebook computers was classified into two main patterns.
 These patterns were differed in terms of the locations, the purposes and the duration of utilization
 of the notebook computer. It was important to note that the patterns proposed in here were to
 facilitate the discussion of the issues related to the utilization of notebook computers by the
 participants and drafting the recommendations of good practices. There were other patterns of
 utilization which were less common than these two but were observed in the field assessment.



 Pattern 1 – Notebook Computers Used Outside Office
         Users of Pattern 1 can be regarded as conventional notebook computer users. The
 notebook computer is used mainly, and in the majority of the cases exclusively, for out-of-office
 use.   The purposes of using the computer are for presentations and/or emailing etc. The
 locations of utilization are mobile such as in clients’ office or even out of the country. The
 duration of use is mostly short such as less than four hours. Because of its mobility, the users
 are likely to require carrying the computer and traveling from one place to another.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 Pattern 2 – Notebook Computers Used Inside Office
         Users belonging to utilization Pattern 2 are those who use notebook computer mainly
 inside the office and/or occasionally outside the office. The purposes of using the notebook
 computer are more diverse than those of Pattern 1. They include word processing, internet
 browsing, information searching, and/or data entry.             The users are likely to use computer
 continuously for four hours or accumulatively for more than six hours. These users may have
 their own workstation in their office. Majority of the utilization pattern henceforth is consistent
 with the definition of DSE User described under the Occupational Safety Health (Display Screen
 Equipment) Regulation, i.e. DSE “User” is defined as an employee who, by reason of the nature
 of his work, is required to use display screen equipment for a prolonged period of time almost
 every day, (a) continuously for at least 4 hours during a day; or (b) cumulatively for at least 6
 hours during a day. Break not exceeding 10 minutes in an hour away from the DSE shall not be
 regarded as breaking the continuity of use of the DSE (Occupational Safety and Health (Display
 Screen Equipment) Regulation, 2003 and The Code of Practice for Working with DSE, 2003).



         Members of both the expert and worker panels were asked to offer their comments and
 feedback on the good practices based on the Regulations, hardware enhancement, notebook
 computer design, training, and other. A summary of the results of the panel discussions is
 presented in Table 33.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



       Table 33 Summary of comments and opinions from the Expert and Worker Panel
 Collation of Comments from Expert and Worker Panels
                                         Legislation-related
  Application of existing Regulation on MHO to the carrying of notebook computers
         Current Regulation on MHO is applicable to handling of notebook computers
         Apply the spirit of the principles under the Regulation on MHO
           Encourage regular break when carrying the machine
           Encourage to reduce the distance of traveling whenever carrying of the machine is
               needed
           Encourage to use proper manual handling techniques
           Encourage to reduce the weight of the machine and its accessories
  Application of existing Occupational Safety and Health (Display Screen Equipment) Regulation
         Current Occupational Safety and Health (Display Screen Equipment) Regulation is
          applicable to the use of notebook computers including the definitions set for
          identification of a user
         Conduct risk assessment for users who meet the definitions set for a “DSE User” or,
         Conduct risk assessment for all notebook computer users disregard their “User” status
         Provide adequate DSE training for all notebook computer users
         Apply the spirit of the Occupational Safety and Health (Display Screen Equipment)
          Regulation
           Encourage users to take regular break
           Encourage users to do regular stretching
           Adopt proper ergonomic design and layout for the workstation on which the
               notebook computer is placed
                             Enhancement of Notebook Computer
  Add appropriate external accessories for prolonged use in word processing or Internet browsing
        Connect external monitor to computer for extending the height of the monitor screen (for
         better monitor to user’s eye-level match)
        Use dock or stand for extending the height of computer screen (for better monitor to
         user’s eye-level match)
        Connect external input devices, e.g. keyboard and mouse to computer (for better
         keyboard/mouse to user’s elbow-level match)
        Use of wrist and/or mouse pad
        Use height adjustable swivel chair (for better seating to workstation height)
  Provide ergonomic carrying bag for taking notebook computer out of the office
        Use backpack for carrying the computer and its accessories
        Use single-side shoulder carrying bag for short distance and lightweight machine
        Use hand trolley for transporting the computer and its accessories for long distance and
         heavyweight machine
        Use alternate hands to hand-carry the bag in which the machine and its accessories are
         kept




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




                                  Improvement of Hardware Design
    Enhanced ergonomic features
           Design of monitor screen
              Larger but lighter screen
              Size of the screen in proportion to working distance, font size etc
              Detachable screen
              Height adjustable screen
           Light weight design
              Reduce overall weight of the machine
              Reduce weight of the transformer and battery
              Reduce weight of the carrying bag
              Reduce weight of the external devices, e.g. CD/DVD ROM
           Design of keyboard and mouse
              Replace fix with detachable or external keyboard
              Use flip-out keyboard (to widen the keyboard space)
              Use tiltable keyboard to accommodate users who prefer working with a slightly
                  extended wrist position
              Build in wrist resting space proximal to the lower edge of the keyboard
              Replace touch pad mouse by external mouse
           Other design feature
              Increase the capacity and durability of the battery
                                              Training
    Equip users with knowledge on the design and set up of the workstation with reference to
     sound ergonomics principles
    Learn proper carrying methods
    Learn to do stretching exercises on a regular basis
                                               Others
    Learn the reasons behind using a notebook computer (for better portability, and out of office
     and/or short duration utilization)
    Encourage to use desktop computer in an office environment
    Encourage to use alternate technology to replace notebook computer
           Use lighter and smaller handheld device, e.g. PocketPC, BlackBerry
           Use external storage device for carrying data or files, e.g. USB or external hard drive
           Use remote or network technology for download data or work tasks via intranet or
             Internet
    Set alternate rest and machine using time (e.g. 50 minute followed by 10 minute break)
    Set restrictions for using notebook computer
           Avoid prolonged typing
           Avoid prolonged browsing




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 4. Proposed Recommendations and Good Practices for Utilization


 Non DSE users Mainly with Out-of-office Utilization
         This type of users is in general those under utilization Pattern 1. The users are required to
 use notebook computer for out-of-office work. The spirit of the MHO principles under the
 Regulation on MHO is for the employers to take appropriate and practical steps on reducing the
 risks associated with lifting and carrying a weight during work. This would call for the employers
 to provide appropriate mechanical aids and/or protective equipment when the users are required
 to carry a notebook computer (and its accessories) outside the office. It is advisable that users
 can be provided with proper type of carrying bag or device such as hand trolley. A few of the
 examples are listed in Table 34.



                     Table 34 Comparison of Different Computer Bag Designs
        Types                   Ergonomic Features      Comments on Usefulness                 Appearance
 1. Backpack                     Left and right       Convenient and hand free               Less
                                  straps distributing  Suitable for long distance              attractive for
                                  loads onto both       and prolonged duration                  users in
                                  shoulders             carrying                                business and
                                 Enable good          Space good for notebook                 in formal
                                  carrying posture in   computer and its peripheral             meetings
                                  the back              accessories
                                 Light in weight
                                 Adequate space for
                                  loading

 2. Hand Trolley                 Less loading on          Space good for notebook            Less
                                  users shoulders           computer and its peripheral         attractive for
                                 Pulling with one          accessories                         users in
                                  hand or alternate        Lifting of hand trolley and         business and
                                  hands, and traction       its content when climbing           in formal
                                  force in shoulders        stairs and crossing curb            meetings
                                  and elbow                Excessive pulling of the
                                 Heavy in weight           trolley may lead to upper
                                                            limb musculoskeletal
                                                            disorders
                                                           Only suitable for long
                                                            distance and duration
                                                            carrying



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




          Types                 Ergonomic Features Comments on Usefulness                   Appearance
 3. Single-side/                 Only one strap      Exert relatively heavy              Slim and
    Messenger Bag                 putting load on      load on one shoulder                 smart looking
                                  either the left or  May lead to improper                Conventional
                                  right shoulder       posture on the shoulder              to users in
                                 Light in weight      and the back for                     business and
                                 Adequate space       compensating the                     attending
                                  primarily for        uneven distribution of               formal
                                  notebook computer    load                                 meetings
                                                      Suitable for short
                                                       distance and duration
                                                       carrying
                                                      Less space for carrying
                                                       other accessories
 4. Hand Carrying                One hand or         The most convenient for             Acceptable by
                                  alternate hands to   carrying                             most of the
                                  carry the notebook  Suitable for short                   users
                                  computer             distance and brief
                                 May use a soft       traveling within the city
                                  sponge bag for      Only good for carrying a
                                  holding the          lift weight and slim
                                  computer             notebook computer
                                                      May exert excessive
                                                       load onto the hand



         Among the four carrying methods, the panel members opined that the “backpack” was the
 most desirable in terms of enhancing the occupational safety and health of users who belong to the
 Pattern 1 as defined in this study. This method was regarded as the most useful when users are
 required for carrying the notebook computer for use out of the office. The “backpack” was
 commented as offering the most ergonomic features and the best for preventing discomforts and
 perhaps work-related disorders among the users. In contrast, the “hand trolley” was regarded as
 less desirable but was useful if users are required to carry notebook computer of heavier in weight,
 larger in size, more peripheral accessories, and/or carrying for long distance travel. This was
 deemed to be quite common in particular when notebook computers are used for sale
 demonstrations and exhibitions.          The panel members also remarked that the “single-side/
 messenger bag” could be useful because of its convenience if users are required to carry a light
 weight notebook computer for short distance daily work travel.



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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



         Besides the carrying bag (or method), the following manual handling recommendations are
 deemed to be appropriate for further enhancing the occupational health and safety of users
 belonging to the Pattern 1 (carrying notebook computer for out-of-office use):
       Keep the load close to the body, i.e. centre of gravity, and back straight
       Swap hand if hand carrying is preferred
       Reduce weight and amount of load to be carried
       Use appropriate aid to minimize weight of load
       Take regular break during carrying
       Reduce carrying distance and duration as appropriate



         It is important to note that users with their utilization pattern similar to those described
 under Pattern 1 are less likely to be defined as “DSE users” under the existing Occupational
 Safety and Health (Display Screen Equipment) Regulation. Nevertheless, it would be desirable
 for the users and their employers to if possible apply the following principles at work:
         Screen is to be positioned in front of the user
         First line on screen is as much as possible to be aligned to the about or just below eye
          level (notebook computer to be placed at a higher than desktop level)
         Screen is to be located at a comfortable viewing distance at 350 - 600 mm, (for instance,
          14-inch wide screen corresponds to about 400mm)
         Screen is easily tilted to suit the needs of the user
         Move computer monitor away from windows or other sources of bright light
         Avoid positioning monitors parallel to windows
         Screen should give a clear, sharp and steady image
         Characters should be of adequate size, with adequate spacing between the characters and
          the lines
         Brightness and contrast of the image should be easily adjusted
         Adjust the contrast and brightness levels on your monitor to find the setting that gives
          you the best clarity
         Use wrist or mouse pad




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



        When taking the notebook computer out of the office, it is recommendable for the users
 and their employers to consider using (or providing) an external mouse to replace the built-in
 touch pad mouse. This will enable the users to operate the pointer function more easily and
 ergonomically. An external keyboard can also be considered if users are required to use notebook
 computer for tying texts. The consequence of adding these external devices is the increase in the
 weight when carrying the notebook computer. The panel members opined that the manufacturers
 of notebook computers could further consider options for adding built-in devices, and reduce the
 overall size and weight of the computer in the future. Below is a list of the features for the
 manufacturers’ consideration:
         Larger but lighter monitor
         Height adjustable monitor
         Reduce weight of battery and electric supply gadget including the transformer
         Improve the life of the built-in battery so that users do not need to carry the transformer
          together with the computer
         Expandable and/or tiltable keyboard to minimize stress on wrist and finger joints
         Built-in external mouse


        One important point raised by the panel members was on the necessity of using a notebook
 computer. The panel members pointed out that it would be the responsibility for the employers
 (or supervisors) to justify the needs for purchasing notebook computers for the use of their
 employees. Justifications would be needed for employees to bring notebook computer for use out
 of the office. Other technologies should be considered before deciding on the use of notebook
 computer. Finally, when a notebook computer is used, the employers and supervisors should be
 mindful of providing adequate training to the employees on its proper use. The content of such
 training may include carrying and lifting technique, ergonomic principles of using DSE, and
 stretching exercises.     A decision tree (Figure 2) was constructed to facilitate employers or
 supervisors making proper decisions on purchase and provision of proper carrying tools for
 employees who are prescribed with notebook computers. The decisions are made according to the
 rules and recommendations suggested by the experts, who were interviewed in this phase of study.




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Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 These experts composed of experts with background and experiences in ergonomic, occupational
 safety and health, medical and healthcare, and employers as well as users.

                                 Performing computer work
    Figure 2                          outside of office




                                   Are there other options available?

                                              For example                                         Yes     Notebook
                             Content can be stored with an external storage/
                              server/ over the Internet and downloaded to
                                                                                                        Computer is not
                                         designated computer                                               needed
                                                   Or
                                Other handheld devices such as PDA



                                                       No

                                           No
                                Notebook Computer is
                                      needed




                                     How much weight is to
                                    carry including document
                                          and peripheral
                                           accessories?                                 Heavy
                     Light



          What is duration                                                     What is duration
          of the carrying?                                                     of the carrying?



                                Overseas                                Long distance or
                                                                           overseas

                                                     Hand Trolley


                       Long distance                                            Short Distance
                                                      Back Pack

                 Short Distance
                                                    Computer Bag

             Very brief duration
                                                  Carry with Hand




     Occupational Safety and Health Council                                                                          78
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems


                                                  Performing computer work
    Figure 2                                      exclusively inside an office


                                        Yes
                                                     Is desktop computer available
                                                              in the office?

                                                                       No

Notebook Computer                  No
      is not                                        Do you have to use a notebook
                                                    computer at different locations
  recommended
                                                                       Yes




                                                    Are these accessories available
                                                               for use?
                         No
                                                   An external monitor, keyboard &
                                                             mouse, or
                                                      A notebook stand, external
                                                          keyboard & mouse



                                                                       Yes


                           No
                                                       Have you received OSH
                                                          related training?

                                                                      Yes


                                                  Notebook can be used


 DSE User Mainly with Indoor Utilization
        Users are those who intensively use notebook computer in their day to day work.
 According to their duration of using a computer, they are regarded as “the DSE Users.” They
 primarily use notebook computers in their offices but may need to occasionally bring the
 computer for out-of-office use. The panel members suggested that users of this type should
 follow the recommendations set mainly for indoor utilization. To cater for out of office utilization,
 users are advised to follow the recommendations made for the “Non User Mainly with Outdoor
 Utilization”.



     Occupational Safety and Health Council                                                               79
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



          Inside the office, users probably use notebook computer continuously for four hours or
 accumulatively for six hours in a work day. They are advised to observe the Code of Practice for
 Working with DSE (2003) and the Occupational Safety and Health (Display Screen Equipment)
 Regulation. A few of the important recommendations modified for notebook computer users are
 suggested below:


 1.    Use of External Monitor
       It is used for compensating the non-detachable and non-adjustable height of notebook
       monitor. In general, when notebook computer is placed on the desktop, the height of the
       notebook monitor is rather low to the eye-level. Any mismatch between the monitor height
       and user’s eye-level may lead to excessive strains in the neck and shoulders which is not
       desirable from an occupational safety and health point of view. Connecting the notebook
       computer to an external monitor which is height adjustable could alleviate this problem by
       eliminating the differences in the monitor height and user’s eye-level. This set up was
       deemed to be crucial by the panel member for the DSE Users. The positioning of the
       external monitor can make reference to Figure 3.


              Figure 3

                                                                             A
                             A
                                                                             B
                             B
                                                                C

                                               F                                         F

                                    E              G                     D       E            G




                                               H                                          H




      Occupational Safety and Health Council                                                              80
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




                                                       A.     The top edge of the screen is about or just
                                                              below the eye level of user
                                                       B.     Keep a comfortable eye distance at 350-
                                                              600mm
                                                       C.     Use of notebook stand to adjust height
                                                              and/or distance of screen of notebook
                                                       D.     Use of external keyboard and mouse
                                                       E.     Enough space in front of the keyboard to
                                                              provide support for the hands
                                                       F.     Keep shoulder relaxed and forearm at
                                                              about right angle to arm during typing
                                                       G.     Keep back straight and rest against
                                                              backrest of the seat and hip at about right
                                                              angle to trunk
                                                       H.     Use height adjustable seat and with armrest

 2.    Dock/ Notebook Stand
       Instead of connecting the notebook computer to an external monitor, one may consider
       housing it into dock or monitor stand (Table 34). This can raise the height of the notebook
       monitor to a higher level resulting in a better monitor height to eye-level match.             For a
       regular size notebook computer (such as 14-inch wide screen), an external keyboard and
       mouse are commonly needed so that the layout of the workstation is ergonomically sound.
       The commercially available options in the local market can be found in Table 34.



                 Table 34 Different notebook stand designs available in the market

            Types of Dock/ Monitor Stand                        Advantages              Disadvantages
                                                             Convenient to be        Not height
                                                              setup on the             adjustable
                                                              desktop                 Inadequate wrist
                                                                                       space at work
                                                                                      Excessive tilt
                                                                                       angle at the wrist

                                                             Height of monitor       Limited range of
                                                              screen is                height adjustment
                                                              adjustable               which may not fit
                                                             Convenient to            all users
                                                              setup                    Connect to
                                                                                       external input
                                                                                       devices




      Occupational Safety and Health Council                                                                81
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




            Types of Dock/ Monitor Stand                       Advantages               Disadvantages
                                                           Height of monitor         Limited range of
                                                            screen is                  height adjustment
                                                            adjustable                 which may not fit
                                                           Document holder            all users
                                                            is available for use      Connect to
                                                                                       external input
                                                                                       devices

                                                           Height of monitor         Inconvenient for
                                                            screen is                  connecting to
                                                            adjustable                 external input
                                                           Flexible                   devices
                                                            positioning of
                                                            notebook
                                                            computer




 3.    External Keyboard and Mouse
       In many circumstances, external keyboard and mouse are the crucial set-up of notebook
       computers in offices. The following are a few considerations for selecting external keyboard:
        Keyboard should be as thin as possible, tiltable and detachable for accommodating
          different work situation and posture of the users
        Keyboard should be neutral in color and non-reflective
        Letters and symbols on the key tops should be clear and easily recognized
        Sufficient space in front of the keyboard to provide support for the hands



          Other ergonomic features and principles for DSE Users using desktop computers are also
 appropriate for the use of notebook computers. They are the use of document holder, wrist or
 mouse rest, adjustable swivel chair, and footrest. Employers should bear the responsibility for
 conducting regular DSE risk assessment for users of this type (Table 35). It is also a good
 practice for employers to provide adequate occupational safety and health training for optimizing
 occupational safety and health in the office.




      Occupational Safety and Health Council                                                              82
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



            Table 35 Notebook computer utilization risk assessment checklist
                                                    Section A
Display Screen                                                                            Y        N      N/A
1. Is the notebook computer connected with an external screen, or being placed on         □        □      □
   a secure docking?
2. Is the screen positioned at about or slightly below the eye level?                     □        □       □
3. Is the screen positioned right in front of the user?                                   □        □       □
4. Does the screen give a clear, sharp and steady image?                                  □        □       □
5. Are the characters readable?                                                           □        □       □
6. Are the brightness and contract adjustable?                                            □        □       □
7. If using external screen, does the screen swivel and tilt? If not using external       □        □       □
   screen, does the screen tilt?
8. Is the screen free from reflections and glare?                                         □        □       □
                                                    Section B
Input Devices                                                                             Y        N      N/A
9.    Are external mouse and tiltable keyboard used?                                      □        □      □
10.   Are the characters on the keys of the keyboard readable?                            □        □      □
11.   Is the keyboard glare free?                                                         □        □      □
12.   Are the input devices positioned at about the elbow level?                          □        □      □
13.   Is there enough space to rest hands in front of the input devices?                  □        □      □
                                                    Section C
Work Desk                                                                                 Y        N      N/A
14. Is the desk surface large enough for the notebook computer, docking/external          □        □      □
    screen, external keyboard, external mouse and documents?
15. Is there adequate leg-room below the desk?                                            □        □      □
Chair                                                                                     Y        N      N/A
16. Is the base of the chair stable?                                                      □        □      □
17. Do the casters allow easy movement of the chair?                                      □        □      □
18. Is the seat height adjustable to suit the body size of the user?                      □        □      □
19. Is the backrest adjustable in both height and tilt to provide adequate support to     □        □      □
    the lower back?
20. Is the seat pan padded and free from sharp edges?                                     □        □      □
21. Do the armrests, if any, allow the user to get close enough to key comfortably?       □        □      □
Document Holder                                                                           Y        N      N/A
22. Us the document holder, if provided, properly positioned to avoid awkward neck        □        □      □
    posture and movement?
Footrest                                                                                  Y        N      N/A
23. Is the footrest, if provided, stable and provided with a non-slip surface?            □        □      □

Illumination                                                                              Y        N      N/A
24. Is the lighting level suitable for the work?                                          □        □      □
Noise                                                                                     Y        N      N/A
25. Is the noise produced by the workstation acceptable?                                  □        □      □
                                                     Section D
Carrying                                                                                  Y        N      N/A
26. If need to carry the notebook computer, is appropriate carrying method used?          □        □      □
.




        Occupational Safety and Health Council                                                            83
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




 PROJECT CONCLUSION



         This consultancy project was conducted between October 2007 and February 2009 taking
 a total of 15 months. There were three stages in the study which provide the necessary data and
 evidence which are useful for the Occupational Safety and Health Council and probably other
 agencies to develop recommendations and good practices for employers and employees when
 using notebook computers in the workplace.



         Stage 1 of this study involved interviews of experts in the field of occupational safety and
 health. The aim was to gain better understanding on the utilization of notebook computers in
 Hong Kong and the problems, if any, associated with the use of the computers. In general, the
 findings indicated that no particular industry or user group predominantly used or not used
 notebook computers, or used notebook instead of desktop computers. The comments gathered
 from the panel also revealed that the users tended to use notebook computers to replace the
 functions used to be covered by desktop computers. As a result, notebook computers were
 commonly used for typing- and browsing-related tasks. Conventional functions such as displaying
 the presentation materials and emailing were no longer the sole reasons for using notebook
 computers. The decision of purchasing or selecting notebook computers was not merely to
 satisfy the needs for out of office use. More often, however, their use was to accommodate the
 limited workspace in small offices, and the purchase polices or strategies of companies.



         Stage 2 of this study was a Telephone Survey on utilization, preference and health-related
 issues associated with notebook computers. The Survey covered adult workers and at the same
 time school-age children. As this study put a focus on adult workers, the results obtained for the
 school-age children were not elaborated in this report. The results revealed that there was
 relatively small proportion (about 10%) of the workers’ population using notebook computers
 (when compared with desktop computers).              Notebook computers were in general used for
 multiple functions with majority of them was typing-related such as word processing and
 browsing the Internet. The typing-related tasks were mostly prolonged in duration such as six


     Occupational Safety and Health Council                                                               84
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



 hours or longer in a day. This perhaps explained the results that relatively large proportion of the
 participants was found to experience musculoskeletal discomforts in the eyes, wrist,
 shoulders/neck and lower back. Prolonged duration of utilization and typing-related tasks were
 found to relate to the larger proportion of the participants experiencing discomforts over the
 shoulders/neck and lower back. The use of external devices such as external monitor and mouse
 added to notebook computers revealed a smaller proportion of the participants reporting
 discomforts in the bodily parts.

         The anthropometric measurements conducted to the participants gathered further evidence
 on the associations between the better worker-workstation match and the lower chances of the
 participants experiencing musculoskeletal discomforts. It is noteworthy that the findings revealed
 from this part of the study largely concur with those obtained from other parts of this study. The
 results revealed that most of the notebook computer participants assumed a rather inappropriate
 working posture when compared with those stipulated in the common practices recommended in
 different health guides published by the Labour Department (i.e. Simple Guide to Health Risk
 Assessment, Office Environment Series – Office Workstation Design, 2003; A Health Guide on
 Working with Display Screen Equipment, 2002) and the Occupational Safety and Health Council
 (i.e. Safety and Health Guides for Working with DSE, 2004) The extent of the mismatch between
 the proper and actual posture was found to have significant association with the chance of the
 participants experiencing musculoskeletal discomforts.            The use of external devices by the
 participants was associated with a smaller proportion of the participants experiencing the
 discomforts. The use of external devices was also found to effectively reduce the discrepancy of
 the worker-workstation mis-matches.

         Last but not least, the materials on different ways for enhancing occupational safety and
 health practices among notebook computer users were developed in this report. Good practices
 were recommended based on the results obtained from Stages 1 and 2, together with the existing
 relevant legal requirements. The materials would be useful to the Occupational Safety and Health
 Council for developing recommendations for alleviating the potential risks associated with using
 notebook computers. These recommendations can be used by workers who are using notebook
 computers or those who have plans to incorporate notebook computers in their workplace.



     Occupational Safety and Health Council                                                               85
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems




         The research team considered the spirit of the existing legal requirements on manual
 handling operation and display screen equipment would be relevant to be applied to notebook
 computer users, especially, those who need carrying notebook computer for use outside the office
 and prolonged utilization in a workday. The notebook computer users were reminded to beware
 proper manual handling operation principles and techniques, for instance, reducing carrying
 weight, duration and distance, and encourage regular break during carrying. Besides, they will be
 encourage using ergonomics gadgets e.g. backpack or hand trolley. Apart from proper carrying
 considerations, notebook computer users are also recommended to make reference to the
 Occupational Safety and Health (Display Screen Equipment) Regulation, principles and
 techniques using notebook computer so as to achieve a match between their anthropometric
 dimensions and the workstation. As a result of the relatively low monitor height of notebook
 computer, the research team recommended using ergonomic external accessories when prolonged
 typing or browsing with the notebook computer is needed, e.g. external monitor/ notebook stand,
 external keyboard and mouse. The employers of the notebook computer users are also reminded
 to conduct regular DSE risk assessment and provide adequate training for users to enhance better
 occupational safety and health using the notebook computers.


 Limitations of study


       The data collected In Stage 1 – expert interview used a qualitative approach. The
 participants were recruited with convenient sample method, whilst these participants might not
 necessarily represent all the industries in Hong Kong. The results obtained from the data therefore
 cannot be generalized to the industries not represented by the participants. It is important to also
 note that the qualitative approach adopted in Stage 1 was aimed to facilitate the research team to
 understand the practices and issues related to use of notebook computer, the research team did
 not attempt to base on the results to formulate conclusions on the issues or recommendations for
 good practices.




     Occupational Safety and Health Council                                                               86
Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



       As mentioned in the previous section, the sample size of the participants of the telephone
 survey conducted In Stage 2a was deemed adequate. The results generated at the group level, i.e.
 working adult versus school-age children would have a good validity. However, the sample sizes
 at the sub-group level such as those who reported using notebook computer or having high level
 of discomfort might be inadequate for generating valid results. Readers should be cautious when
 interpreting the results at this level. The results also cannot be generalized to the population not
 represented by the sub-group samples. Besides, the data obtained from the telephone survey was
 based on participants’ self-report, and their subjectivity, despite the chance is rather slim, could
 have biased the results. On the contrary, the sample size of the participants involved in the field
 assessment conducted in Stage 2b was deemed adequate (results further triangulated by a round
 of telephone survey). The findings on the usage pattern of notebook computer, anthropometric
 measures, and level of discomfort would have good validity. The results and the conclusions
 drawn can be generalized to the populations which the participants represented. Nevertheless,
 readers should still be cautious to make sure that the characteristics of the workstations and the
 ways which the notebook computers are used are similar to those stipulated in this study before
 making the generalization.


         The recommendations of the common and good practices suggested in Stage 3 went
 through a series of consultations with the stakeholders and the occupational health and safety
 experts. The research team believed that the contents should be practical and useful for the
 industries. The main drawback is that the recommendations are feature- rather than industry-based,
 i.e. functional needs of notebook computer. As a result, the recommendations offer only generic
 practices in the needs assessment, design of workstations, and use of accessories and peripheral
 devices, readers would need to devise the practices specific to their workplace and job description
 needs. Besides, the recommendations cover only the two most common work scenarios, readers
 should base on the examples given in the report and develop their own practices for those which
 do not fall under these two categories.




     Occupational Safety and Health Council                                                               87
   Final Report on Use of Notebook Computers and Related Ergonomics and Occupational Safety and Health Problems



     WORK SCHEDULE

         Months    1st   2nd   3rd        4th   5th   6th  7th         8th   9th     10th 11th          12th     13th 14th 15th
                           st                           nd
                          1 Quarter                   2 Quarter                      3rd Quarter                    Final Quarter
Tasks:
Stage 1 Study                  
Stage 2a Study                                 
Stage 2b Study                                                                                          
Stage 3 Study                                                                                                   
Interim Report                                                                                                       
Final Report and                                                                                                            
Guide Book
Presentation 1
Presentation 2
Presentation 3
Presentation 4




     WORK PROGRESS SUMMARY:
    Task   Task Description           Progress         Schedule    Actual Start   Scheduled                       Actual
    No.                                               Start Date      Date      Completion Date                Completion Date
     1.  Phase 1 – Expert             Completed          Oct 07      Oct 07         Feb 07                        Feb 08
         Interview
     2.  Phase 2 – Telephone          Completed         Dec 07          Nov 07            Feb 08                   Jan 08
         Survey
         Phase 2 – Field              Completed         Dec 07          Dec 07            July 08                  Aug 08
         Assessment
     3   Literature Review and        Completed         Sep 08          Sep 08            Nov 08                   Jan 09
         Expert Interview




          Occupational Safety and Health Council                                                                            88