Publish Time: 2021-11-08 Origin: Site
The purpose of this news is to explain the principles of safe chemical storage in laboratories and to provide guidance on best practice. It is not a definitive guide and in all cases the material safety data sheet [MSDS] for the substance must be referred to in order to determine safe storage conditions and any incompatibilities.
There is a range of storage facilities suitable for chemicals in the laboratory environment. Several of these are specially designed for the safe storage of different types of hazardous substances. It is important to understand what substances can be safely stored in which storage container.
Labelling. All chemical containers must be appropriately and clearly labelled with the following information:
Name of substance
Hazard category (e.g. corrosive, flammable, oxidising, toxic).
In situations where there may be very small vessels or sample vials containing hazardous substances, such that individual labelling is not practicable, these should be secured within a secondary container such as a rack or tray which should then be labelled as above.
Compatibility. It is essential to segregate incompatible substances. The improper storage or mixing of chemicals can result in serious incidents and injuries.
Minimise quantities. Store the minimum stock levels of hazardous materials that is reasonable for the level of usage in the lab. Large quantities of hazardous materials should be stored in purpose built external chemical stores.
Maintain good housekeeping. As in all work areas, clutter should be kept to a minimum on general shelving as well as in storage cabinets/cupboards.
Maintain good stock control and be aware of time-sensitive compounds such as ethers which once opened and exposed to the air can produce peroxides which are highly explosive. This means a regular review of what is being stored and disposal of surplus or unwanted chemicals. Pay particular attention to expiry dates and the date when a bottle is first opened should be clearly shown on the label.
Do not store chemicals under sinks as they may leak and some chemicals react when wet.
Store large breakable containers, particularly of liquids, below shoulder height. Storage of other materials e.g. plastic containers, above this height is acceptable provided that there is a safe means of access to the storage location.
Sensible shelf storage – ensure shelves are not so high that workers need to access them via the benches or lab chairs. Keep light and/or infrequently used containers on the higher shelves. Lips on shelves are helpful as is ensuring that Safety Office chemicals stored on shelves over the centre of the bench, cannot be pushed back and fall off the far side. Items in cabinets should be stored on trays, whether the trays be integral to the storage cabinet or are additional.
Shelving provided for storing hazardous substances should be fit for purpose and fitted to an appropriate standard by a competent person. The following principles should be followed in relation to storage on shelves
3.1 Do not overload shelves – if they are bowed they are overloaded. Store breakable containers, particularly of liquid and hazardous chemicals below shoulder height.
3.2 Store large heavy containers at low level
Where items are stored above this level ensure they are light weight/infrequently used and that there is a safe means of access [ e.g. step stool or ladders].
3.3 Central shelving on benches should have raised edges/lips to prevent items being pushed off the other side.
3.4 Acid cabinets
Modern versions are made of acid resistant materials [such as polypropylene, HDPE or wood] and contain a tray to catch any leakage or spillage. Wooden cabinets should not be used for storage of oxidising acids such as nitric or perchloric. Some acid storage cabinets currently in use may be made of metal and after prolonged use will show signs of corrosion. Where acid storage cabinets are acquired for the first time, or old ones replaced these should be acid resistant.
3.5 Flammable solvent cabinets
These are made of either metal or wood with a minimum fire resistance of a half hour. They should contain a spillage tray made of suitable material that is compatible with solvents.
3.6 Ventilated cabinets
These are cabinets which are fitted with forced ventilation. They may be free-standing with their own extract system, or may be situated beneath a fume cupboard and attached to its duct. They are designed to safely store chemicals that give off noxious fumes and smells. These fumes are sucked away by the forced ventilation.
3.7 Fridges & freezers
It may be used for storage of certain hazardous substances however where the substances are flammable the unit must not contain any internal light source or thermostat that could provide a source of ignition for any flammable vapour. Proprietary laboratory fridges and freezers that meet these requirements are available from major lab supply companies, domestic appliances should be avoided.
3.8 Fume cupboards
It is not designed or intended to be used as storage areas and they should be kept clear of materials and containers when these are not needed for the ongoing operational work. Materials stored in fume cupboards may disrupt the air-flow making the fume cupboard less efficient and compromising the safety of the user.