Autoclave Guidelines _Draft_

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Autoclave Guidelines _Draft_ Powered By Docstoc
					  OSHEU Guidance Document

   Using 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), effective autoclaving results 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 covered 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.      Registering Autoclave Equipment
As autoclaves are ‘pressure vessels’ all autoclave equipment (including bench-top
autoclaves and pressure cookers) must be formally registered with Cardiff University
Estates division. The Estates division will ensure that all items on their central
register are included in the required annual safety checks carried out through the
University’s insurance provider. It is important therefore, that individuals who
purchase or acquire any type of autoclave equipment inform their

School/Department so that they are formally registered. A good way of doing this is
by providing your departmental safety officer (DSO) with the necessary information.
The installation of larger, free-standing autoclave equipment in some Schools and
Departments will automatically require input from the Estates division and
registration should therefore be routine. However, Schools/Departments need to
confirm that registration has occurred.

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

    Physical injury to persons in the vicinity caused by a 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 equipment

5.      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.

5.1    Basic electrical safety measures

   Be aware of the inherent risk of electrocution when using electrical equipment
    especially when filling the autoclave chamber manually with water
   School/department to ensure portable electrical equipment is included in
    portable appliance testing (PAT) schedule (frequency will depend on the degree
    of use e.g. yearly?, 6 monthly?)
   Carry out regular visual checks on power supply cables and report any damage
   Check equipment holds a valid PAT sticker confirming they are within test dates
    and report items that are not in compliance to relevant person (laboratory
    manager or principal investigator)

5.2 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 5.5.).

5.3 Training
Training should be carried out by competent individuals with the relevant
knowledge, practical experience and relevant training regarding the equipment 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.

5.4 Local Rules and Standard Operating Procedures
The introduction of 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 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.

5.5 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.

5.6 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 laboratory coat, safety glasses/visor and heat resistant-gloves will be the
minimum needed during unloading.

6.      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 where longer cycle times can affect 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 parts of your body in the escape
    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
     validated 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 their usual designated waste stream).

7.      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. For older autoclave equipment
there are a number of commercially available tests that can be used e.g.
Thermalog® S steam sterilization indicator strips or the use of heat-stable spores of
Bacillus stearothermophilus. The use of standard autoclave tape however, is not
reliable in validating autoclave function (colour change will occur at a certain
temperature irrespective of how long the temperature was held). 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 sustained (e.g. holding time) for the required 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

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