Guidelines

Storage of Chemicals in Fridges, Freezers and Cold Rooms - Guidelines

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1. Purpose and Objectives

The storage of flammable solvents, gases and powders in laboratory refrigerated units presents a risk of fire or explosion.

2. Definitions, Terms, Acronyms

Aus Ex - Australian National Certification Scheme

LEL- Lower Explosive Limit

3. Guidelines Scope/Coverage

This guideline is for use by all staff and students at The University of Queensland who need to store flammables in refrigerated conditions.

4. Guidelines Statement

Storing chemicals in laboratory fridges, freezers and cold rooms is a practice that can result in fire or explosion when flammable or volatile compounds are stored incorrectly. There is the potential for damage to equipment and property from fire and explosion as well as personal injury. The University therefore requires that all refrigerated units used for storing volatile chemicals must be Ex rated.

5. Background Information

Refrigerated units can be used to store volatile, noxious and air-sensitive material and it is possible for the atmosphere inside the unit to become saturated with chemical vapours if not properly sealed. Over time these vapours can penetrate porous surfaces and lead to odour problems.

Similarly, material from spills or leaking containers can impregnate surfaces that then give off odours long after the original material is removed. The Australian Standard AS/NZS 2243 series requires that flammable and combustible liquids are stored away from ignition sources and from excessively hot locations.

Any electrical systems installed in hazardous locations, where the lower explosive limit (LEL) could be exceeded, must be Ex rated in accordance with the zoning classification and hazard class (AS/NZS 2381.1:2005). Alternatively electrical sockets, switches and equipment may be located away from the hazardous location. Similar consideration must also be given to the location of switches and sockets in relation to where chemicals vapours may accumulate or be vented to from a refrigerated unit.

Loss of electrical power can also produce extremely hazardous atmospheres as chemicals warm up or decompose.

Examples of ignition sources include:

  • Switches associated with the internal light and thermostat.
  • Timers and heating elements in frost free fridges or freezers.
  • The compressor motor, if the cabinet is not effectively sealed and vented.
  • Power points.
  • Electrical equipment running inside fridges and cold rooms.

5.1 Existing fridges freezers and cold rooms

  • All refrigerated units, which are currently used to store flammable chemicals, must be "spark free".
  • The University of Queensland stipulates that only approved refrigerators and freezers designed for laboratory use should be used for flammable chemical storage (chemicals with a flash point below 37.7ºC).
  • All ordinary domestic refrigerators and freezers must be labelled with the phrase ‘no storage of flammable solvents or samples in flammable solvents within this fridge/freezer/cold room’.

6. How to Store Chemicals within the Fridge, Freezer or Cold Room

The following steps should also be followed to reduce offensive odours and the release of vapours into the refrigerated unit:

  • Wrap the caps of volatile materials bottles and tubes with Parafilm.
  • Place volatile materials in Ziplock bags.
  • Place the sealed wrapped chemicals in removable trays or containers (this ensures that when spills occur, the storage container can be removed easily for cleaning).
  • Promptly clean up any spilled material.
  • Cork and glass stoppers are unacceptable - they do not form good seals. Screw-caps with a seal inside may provide a solution, but only if closed correctly.
  • Regularly inspect container integrity for cracked caps or blurred labels.
  • Do not overfill the refrigerated unit. Restrictions for flammables within a 10m radius still apply. See Flammable and Combustible Liquids: Storage and Handling-Procedures.
  • Hazard labels for Class 3 flammables must be attached to the outside of the door of the refrigerated unit (fridge, freezer or cold room).

Dispose of old chemicals through the University chemical waste program, when no longer needed or when the expiry date has passed.

7. Contacts for Further Information

OHS Division:  OHS@uq.edu.au

University of Queensland Chemical Store

https://chemstore.science.uq.edu.au/LoginStore.aspx

email at chemwaste@Chemistry.uq.edu.au

Custodians
Director, Occupational Health and Safety
Mr Jim Carmichael
Custodians
Director, Occupational Health and Safety
Mr Jim Carmichael