What happens if I overload my flammable liquids cabinet past its capacity rating? 

Oct 7, 2019 Posted by Walter Ingles

Flammable liquids cabinets in Australia have a capacity rating that must be displayed on the front of the cabinet and clearly visible whenever the cabinet doors are closed. In this blog we’ll be discussing the importance of keeping chemical quantities stored in the cabinet within the capacity rating. Overloading the cabinet can put you in breach of Australian Standard AS1940:2017 –- The storage and handling of flammable and combustible liquids and has wider risk implications for your business.

Cabinet functionality 

Class 3 Flammable Liquids cabinets that have been manufactured to Australian Safety Standard AS1940:2017 fulfil three important functions — overloading the cabinet past its capacity rating will impede the cabinet’s ability to safely contain the liquid chemicals and flammable vapours. We’ll unpack each separately below: 

1. Fire safety buffer

Indoor flammable liquids cabinets are specifically designed to create a fire safety buffer and protect the chemicals from radiant heat, as well as ignition sources. If a fire was to break out at the job site, the cabinet gives your workers a 10-minute safety window to activate fire protection systems and evacuate the area before the integrity of the cabinet is breached. 

Overloading the cabinet can inhibit this functionality as oversized drums and containers can prevent the cabinet doors from fully closing and creating a proper seal. Train your workers to load the cabinet correctly and ensure that drums are never stacked more than two high if they are greater than 60 litres. 

2. Spill containment

AS1940:2017 requires a flammable liquids cabinet to have a liquid tight spill compound that is capable of holding at least 25% of the chemicals stored inside the cabinet, or 100% of the contents of the largest container (whichever is greater).  

Overloading the cabinet will render the spill compound ineffective and may place you in breach of Section 357 of the WHS Regulations which requires you to have facilities in place for containing and managing chemical spills. 

Make sure your workers know (and understand) the spill capacity of the cabinet and ensure that only containers with lids, seals or caps are stored in the cabinet. At the same time only one drum of more than 60 litres is allows to be stored horizontally at any time. 

3. Vapour containment

Flammable liquids emit flammable vapours which are a fire and explosion hazard, as well as potentially harmful to workers who inhale the fumes. Each cabinet is designed to contain a certain amount of chemical vapours and overloading the cabinet may create an explosive atmosphere inside the cabinet — or create unsafe concentration levels for workers loading or decanting. 

At the same time, if the doors won’t close or seal properly, flammable vapours will escape and may begin to accumulate in low lying areas (e.g., drains, pits). These vapours remain in their flammable range and may react dangerously with incompatible materials and substances. 


Aggregate quantities 

Flammable liquids must be kept within strict aggregate quantities and overloading a cabinet may place you in breach of maximum allowable quantities. In Australia the aggregate capacity of indoor flammable liquids cabinets is 850 litres per 250 m2 (ground floor) and 250 litres per 250 m2 (other floors). Aggregate quantities must be separated by at least 10 metres. 


Other business implications 

Flammable liquids safety cabinets that have been manufactured to Australian Safety Standards are known hazard control measures and accepted by WHS Regulators as industry best practice. But using them incorrectly (eg, overloading) will render them an ineffective safety measure which may breach your WHS compliance.  

If the cabinets are overloaded any risk assessments you’ve conducted will be ineffective, and you may be in breach of the following legislative requirements: 

  • Providing a workplace free of risk, and ensuring the health and safety of workers when handling hazardous substances (Section 19 WHS Act). 
  • Minimising hazards according to the Hierarchy of Controls, and ensuring the control measures remain effective and used correctly (Sections 32-38 of the WHS Regulations). 
  • Ensuring workers understand the nature of the hazards associated with the substances they use or handle (Section 39 WHS Regulations). 
  • Keeping air-borne contaminants and chemical concentration levels within Workplace Exposure Standards (Sections 49-50 WHS Regulations). 

IMPORTANT: If your risk assessments are rendered ineffective and you are in breach of WHS legislation, your insurance policy may also be affected if there was a fire, explosion, or dangerous chemical reaction at the job site. 


Next steps 

If you use a Class 3 Flammable Liquids cabinet at your workplace we encourage you to download our free eBook Essential Considerations When Storing Flammable Liquids Indoors. We unpack the critical elements of an indoor safety cabinet for storing flammable liquids, and you’ll have the information you need to determine if the cabinets at the job site are still effective, safe and compliant. Download and read it today by clicking on the image below:  

Essential Considerations when Storing Flammable Liquids Indoors download Free eBook

Walter Ingles

Walter Ingles Compliance Specialist

Walter is STOREMASTA’s Dangerous Goods Storage Specialist. He helps organisations reduce risk and improve efficiencies in the storage and management of dangerous goods and hazardous chemicals.

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