Autoclave Guidelines Draft

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					  OSHEU Guidance Document

          Autoclave Equipment

  Author                       Sheridan Morgan

   Date                          March 2010

Review Year                         2013

  This guidance has been Equality Impact Assessed

1.      Introduction
Autoclaving is the preferred method for sterilizing / decontaminating equipment,
sterilizing media and for inactivating waste harbouring micro-organisms. The process
relies on a combination of heat (steam in most cases) and pressure. Unlike chemical
disinfection (where success is demonstrated by an acceptable reduction in viable
micro-organisms e.g.~ 5 Log10 reduction), correct autoclaving will result in a 100%
kill rate. It should therefore be the first choice method (wherever practicable) for
inactivating waste harbouring both wild–type and genetically modified micro-
organisms. There are several types of autoclave in use at Cardiff University:

    Free-standing autoclaves with a large volume capacity (e.g. several hundred litre
     capacity) which are integrated into the services of a building e.g.
     water/steam/electrical systems
    Portable bench-top autoclaves (electrical) which are common in laboratories and
     used for small scale operations (e.g. 25L capacity); and,
    Portable pressure-cookers which have a similar capacity to portable bench top
     autoclaves. Portable-pressure cookers are rare within the University-but may still
     be present in some areas. They can be powered electrically or less commonly by
     gas burner.

The aim of this guidance document is to provide general health and safety
information regarding the use of autoclave equipment. Following the guidance will
help ensure that anyone authorised to use this equipment (as part of Cardiff
University’s undertakings) are able to do so without compromising the health and
safety of themselves and others. The document also provides general information
and measures that will help ensure your autoclaving is effective.

2.      Legislation and guidance
The use of autoclave equipment is covered under several health and safety
regulations. Under these regulations Cardiff University as an employer, as well as
any of its staff, students and visitors will have specific health and safety
responsibilities regarding their use. The major legislative regulations include:

    Health and Safety at Work etc. Act 1974
    Management of Health and Safety at Work Regulations 1999
    Provision and Use of Work Equipment Regulations 1998

Specific legislation regarding autoclave equipment is provided under the Pressure
Systems Safety Regulations 2000 (PSSR 2000) which covers the protocols and
procedures in relation to their maintenance, servicing and safety inspection. It is
the responsibility of the School/Department to ensure procedures are in place to
comply with these regulations. Guidelines on the use of autoclave equipment in the
laboratory setting are provided under British Standard (BS2646-3, 1993).

3.      Health and Safety Responsibilities
The health and safety responsibilities of all personnel at Cardiff University are fully
described in the Cardiff University Safety, Health and Environment Policy. Specific
responsibilities regarding health and safety management of autoclave equipment are
also provided in the following text of this guidance document.

4.      Registering Autoclave Equipment
Autoclaves are ‘pressure vessels’ subject to PSSR 2000 and all types of autoclave
equipment (including bench-top autoclaves and pressure cookers) must be formally
registered with Cardiff University Estates division. This includes equipment in
University departments residing in buildings not owned by the University (e.g.
departments in buildings owned by the Cardiff and Vale University Local Health
Board). Registration will require sending an explanatory email to Estates that
includes the details of the School/Department, the room number where the
autoclave is sited, the make and model of the autoclave and its serial number. The
Estates division will ensure that all items registered are included in the required
annual safety checks carried out through the University’s insurance provider.
Individuals who purchase or acquire any type of autoclave equipment must inform
their School or Department to ensure formal registration occurs. A good way of
doing this is by providing the departmental safety officer (DSO) with the necessary
information who will then notify Estates. Although the installation of larger, free-
standing autoclave equipment will automatically require input from either the
University Estates or Trust Estates divisions, Schools/Departments should ensure the
equipment has been formally registered as described above.

Please note that the registration of autoclaves and the subsequent safety
inspections carried out by the University insurers are additional requirements to
the necessary servicing and maintenance programmes agreed with the autoclave

5.      Main Hazards
Hazards may be general or specific, depending on the design of the autoclave or
pressure cooker. They include:

    Physical injury to persons in the vicinity from the rapid release of stored energy
     resulting from autoclave failure (e.g. failure of doors/lids)
    Physical injury from exploding vessels that have become pressurised during
     processing (e.g. glass containers)
    Scalding / burns from steam or the hot contents of items being processed
    Risk of infection from pathogenic micro-organisms due to inefficient deactivation
     of the waste
    Inadvertent release of genetically modified organisms to the environment
    Manual handling issues during loading/unloading heavier items
    Electrocution (e.g. damaged/wet electrical components)
    Fire hazard (e.g. human error – leaving manually operated autoclave equipment

6.      Using autoclaves safely
First and foremost it is imperative that the use of any autoclave equipment should
be carried out to the manufacturer’s guidelines. Any health and safety measures
recommended in these guidelines should be implemented and adhered to.

The majority of large, free-standing autoclaves will be situated in designated areas
and operated by specifically trained technical staff - and anyone using the service
should comply fully with the local rules in place. In University departments where
there is not a designated autoclave technician, laboratory workers may be required
to operate the autoclave equipment themselves. In such cases individuals with a

good level of laboratory experience will be the preferred candidates for receiving
the necessary training. Undergraduate students should not be responsible for
operating large free-standing / industrial type autoclaves.

Most laboratory users including undergraduate students however, will need to
operate portable bench-top autoclaves (and possibly even pressure-cookers) on a
regular basis. It is important that adequate training is provided to ensure that users
do not cause harm to themselves and others or cause damage to University property.
This is particularly important in regard to the use of pressure-cookers as they
require a greater level of operator input and supervision during operation.

Note. The Occupational Safety Health and Environment Unit (OSHEU) does not
support the use of manually operated electric or gas powered pressure-cookers in
laboratory environments.

6.1 Basic electrical safety measures
 Be aware of the inherent risk of electrocution when using electrical equipment
   especially when manually filling the autoclave chamber with water
 Carry out regular visual checks on power supply cables and report any damage
 Check equipment holds a valid portable appliance test (PAT) sticker confirming
   they are within test dates and report items that are not in compliance to a
   relevant person (laboratory manager or principal investigator)

6.2 Fire
The risk of fire should not be ignored when using autoclaves. Pressure-cookers
powered by gas or electrical heating plates will inherently pose a greater fire hazard
compared to modern bench-top autoclaves. The fire hazard and any control
measures should therefore be considered in the risk assessment (Section 6.5.).

6.3 Training
Training should be carried out by competent individuals who have the relevant
knowledge, practical experience and training regarding the equipment/task in
question. It is the responsibility of the Schools / Departments through managers and
principal investigators to ensure anyone using autoclave equipment is adequately
trained to do so. Records of any training should be retained.

6.4 Local Rules and Standard Operating Procedures
Local rules and standard operating procedures (SOP’s) are important to help manage
the associated risks - together they should cover all safety critical tasks associated
with autoclave use. Local rules should be simple and concise – e.g. indicating the
equipment, what it is to be used for, its location, who is authorised to use it,
functional test procedures and the transportation of items/waste to and from the
area. The SOP’s should provide clear and simple instructions for using the
equipment safely. Wherever possible, autoclave equipment should be sited away
from areas where workers carry out routine laboratory procedures.

6.5 Risk assessment
A suitable and sufficient risk assessment for the procedure must be in place prior to
any autoclaving task being carried out. Anyone intending to use autoclave
equipment will have read the risk assessment and confirmed with their supervisor
that they understand its content before signing and dating the document. The

principal investigator/laboratory manager is responsible for developing, reviewing
and retaining the risk assessment document.

6.6 Personal protective equipment (PPE)
The requirement for appropriate PPE when loading / unloading the autoclave will be
identified through the risk assessment. For example, during loading procedures a
laboratory coat and laboratory gloves are likely to be the minimum requirement,
while a laboratory coat, safety glasses/visor and heat resistant-gloves will be the
minimum PPE needed during unloading.

7.      Important points for safe and efficient autoclaving

    Items for re-use should be able to withstand the conditions generated by the
     autoclave equipment (thermo-stable). Waste items that are not for re-use (and
     may not be thermo-stable) should be held in suitable containers
    Tops of bottles/containers should not be fully tightened, but loose enough as to
     allow for gaseous escape and prevent them becoming pressurized when heated
    Containers holding liquids should not be overfilled to avoid the contents from
     ‘boiling-over’ into the autoclave chamber
    Keep liquid volumes as small as possible as larger volumes take longer to heat up
     and cool down. Filter-sterilization may be an alternative for some types of heat
     sensitive media or where longer cycle times may adversely affect media quality
    Avoid packing items tightly into the autoclave chamber as this may prevent
     efficient steam penetration and effective sterilization
    Ensure the ‘necks’ of bags containing waste material are opened wide enough to
     allow for efficient steam penetration
    Ensure the lids/doors of the autoclave are closed properly before starting
    If there are any problems with equipment abort the process and inform those in
    Allow the autoclave chamber to return to atmospheric pressure and a reasonable
     temperature before attempting to open the door/lid to remove items. Interlocks
     and pressure release valves should not be overridden to reduce cycle times
    On opening autoclaves be mindful of the possibility of escaping steam and
     erupting containers – avoid placing unprotected body parts in the escape path
    Hot items removed from the autoclave should be placed in a suitable cooling-
     area and indicated as ‘hot’ to warn others of the hazard
    Manually operated pressure-cookers should never be left unattended during
    ‘Make safe’ cycles intended to inactivate waste containing biological pathogens
     or genetically modified organisms should not be carried out in bench-top
     autoclaves or pressure-cookers. This type of waste should be deactivated in
     integrated, free-standing autoclaves where function is verified through
     recognized means.

Materials should not be autoclaved if they:
 Contain radioactive material (contact your School/Departmental Radiation
   Protection Supervisor (RPS) or the University Radiation Protection Advisor (RPA)
   at OSHEU)
 Contain or are suspected of containing hazardous chemicals (solvents or
 Chemicals that will become unstable/volatile at elevated temperatures

    Contaminated sharps. (Note: In special cases e.g. specific GM projects,
     permission may be given to allow sharps contaminated with GM micro-organisms
     to be autoclaved prior to them entering a specific waste stream).

8.      Verification of autoclave function
Validation of autoclave function when deactivating biological agents (especially
pathogenic or genetically modified organisms) should be carried out for each load
with the results recorded in the autoclave log book. The use of standard autoclave
tape is not reliable in validating autoclave function as colour change will occur at a
certain temperature irrespective of how long the temperature was held. For older
autoclave equipment there are a number of commercially available test kits that
can be used e.g. Thermalog® S steam sterilization indicator strips or the use of heat-
stable spores of Bacillus stearothermophilus. The Brown 121 TST pack can be used
in relation to the Bowie – Dick test to evaluate steam penetration in horizontal
autoclaves. The test is described in BS EN ISO 11140-3:2009 (Sterilization of health
care products. Chemical indicators. Class 2 indicator systems for use in the Bowie
and Dick-type steam penetration test). Strategically positioned heat probes are
important to verify internal temperatures especially when autoclaving large liquid
volumes where the required temperature in the bulk fluid must be held for a
designated length of time. Modern autoclaves may have electronic systems in place
that automatically provide verification of each deactivation cycle.
Note. It is important to adhere to the manufacturer’s guidelines when using any
commercially available and other relevant functional tests.

A guide to conditions for effective sterilization of typical loads

        Procedure          Temperature range           Holding Time at
                                 (oC)                   temperature

Sterilization of liquids          121-124                       15
                                  115-118                       30

       Sterilization of           121-124                 15 (minimum)
     glassware or other           126-129                 10 (minimum)
         equipment                134-138                 3 (minimum)

  Deactivation of                 121-125                 15 (minimum)
   contaminated                   126-130                 10 (minimum)
materials (make-safe)             134-138                 3 (minimum)

Adapted from BS2646-3:1993

9.      Useful Contacts
    Departmental Safety Officer (DSO)
    School/Department Biological Safety Officer (BSO)
    University Biological Safety Advisor (BSA) : Dr. Rachel Coombe – OSHEU
    Scientific Support Officer : Dr. Sheridan Morgan - OSHEU
    Occupational Safety, Health and Environment Unit (OSHEU) – 47 Park Place


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