Abstract to International Conference on Healthy Air - Better Work 29-31, May 2007 Helsinki
Acoustic environment in Finnish offices - the summary of questionnaire studies
Riikka Helenius, Esko Keskinen,* Anu Kaarlela-Tuomaala, Valtteri Hongisto Finnish Institute of Occupational Health, Laboratory of Acoustics, forename.surname@ttl.fi * University of Turku, Department of Psychology, esko.keskinen@utu.fi Introduction and objectives. Noise is often the most detrimental factor of the indoor environment in offices, especially in open-plan offices. However, there is very little published evidence on that since the proper understanding of acoustical environment and its effects on workers presupposes close co-operation between acousticians and work environment psychologists. This kind of co-operation started between FIOH and UTU in 2001. The questionnaire of the acoustic environment of offices was finished in 2002. The questionnaire was developed to acquire subjective data from intervention studies where the acoustic environment is changed significantly. Results of some intervention studies in individual offices have been published elsewhere. However, the results from these individual offices do not give a general picture of the prevalence of noise problems in offices. The aim of this study is to summarize the questionnaire data from 8 offices studied thereafter. Materials and Methods. Two-thirds of the respondents worked in the open-plan offices and the rest worked in 1 – 4 persons' rooms, altogether 633 persons. People worked in various areas including administrative, economical, clerical and engineering work. The acoustical conditions were measured. From the room acoustical point of view, the offices represented typical Finnish offices. Results and Discussion. Noise and thermal conditions were experienced as the most disturbing work environment factors. Ventilation noises were very seldom mentioned as disturbing despite large variations in ventilation sound levels. The most distracting sound sources were nearby speech and noises from human activities, i.e. office noise. Office noise was most detrimental to cognitively demanding work tasks. People changed their working strategies to cope with office noise. The acoustic environment was experienced much more unsatisfactory in open-plan offices than in few-person office rooms. This could not be explained by the variation between noise levels but variation between speech privacy. Speech intelligibility is lower in single-person offices which reduces distraction caused by speech. Also speech privacy was better in single-person office rooms. Conclusions. The studied offices formed a reasonably representative cross-section of typical offices in Finland. This summary gives evidence that noise is really a major problem in offices, especially in open-plan offices. Today, the relative amount of open areas in new office buildings is increasing. This means that more and more demanding work tasks are located in open areas. The standard workstation size seems to decrease permanently because of flat computer displays. These trends will probably increase the prevalence of noise problems. The acoustical designer should seriously commit himself both on the relative amount and acoustic quality of open areas, single-person rooms and special retiring and phone-call rooms.