Flammable liquids are Class 3 Dangerous Goods and produce flammable vapours that can ignite at room temperature. Many flammable liquids also emit other hazardous fumes which can be toxic and corrosive. In this blog we’ll be discussing the ventilation capabilities of an indoor flammable liquids cabinet and how to determine whether you need to install an adjunct ventilation system to dissipate hazardous vapours or fumes.
Understanding indoor flammable liquids cabinets
Let’s start by taking a closer look at the way an Indoor flammable liquid storage cabinet is constructed. A Class 3 Flammable Liquids safety cabinet (manufactured to Australian Standards) is designed to fulfil four important functions:
- Protect the flammable chemical containers inside the cabinet from being dropped, knocked over, impacted, or misused by unauthorised people.
- Segregate the flammables from ignition sources and incompatible substances.
- Contain any leaks or spills seeping from broken or damaged containers.
- Insulate the chemicals from fire — providing at least 10 minutes for workers in the area to evacuate or activate fire protection systems.
Flammable liquids cabinets are dual-skinned — meaning they are constructed from double-walled sheet steel and do not have louvered vents. All vapours and fumes from the chemicals are contained within the cabinet.
One of the key reasons flammable liquids cabinets do not have louvered vents is because they need to protect the chemicals from any fire burning outside the cabinet. This design ensures flammable vapours are fully contained inside, and the cabinet offers complete protection from fire. But this is what causes the issue with ventilation.
In Australia there are three documents that can determine a need to install a ventilation system in a safety cabinet. We’ll look at each of them separately below:
1. Australian Safety Standards
Ventilation requirements when storing Dangerous Goods are detailed in the relevant Australian Standard. The relevant Standard for Class 3 Flammable Liquids is AS1940:2017 – The storage and handling of flammable and combustible liquids. Many Australian Standards do require mechanical ventilation systems, but AS1940:2017 has no mandatory requirement for adjunct ventilation.
2. WHS Regulations
Section 40 of the WHS Regulations requires that the working environment must be properly ventilated — in a way that enables workers to carry out their work without risk to health and safety. What this really means if there is any indication that ventilation is insufficient, you should conduct a risk assessment.
3. Workplace Exposure Standards
One specific indicator that will almost always trigger a risk assessment is if any of the flammable liquids you are carrying has a workplace exposure standard. When chemicals release hazardous vapours, mists, gases or fumes, hazardous molecules can accumulate in the breathing zone of workers and other people. Workplace exposure standards set the upper limits of chemical concentrations and the maximum exposure times.
If you do decide to install a ventilation system, we recommend the following essentials:
- Ensure the ventilation system prevents flammable vapours and hazardous fumes from escaping into any room.
- Direct vapours and fumes to a safe location outside that is away from ignition sources and areas where workers (or other people) congregate.
- Flammable vapours are denser than air and accumulate in the bottom of the cabinet. The air inlet should be at the top of the cabinet and vapours should be extracted from the bottom with an exhaust fan.
- Ventilation systems must be standalone and cannot be shared among cabinets.
- Ventilation system should be designed and installed by an appropriately qualified engineer and technician.
- A ventilation system must not compromise the structural integrity of your flammable liquid storage cabinet.
Minimising chemical vapours naturally
There are ways to minimise chemical vapours naturally, STOREMASTA recommend these practices with (or without) adjunct ventilation.
- Never overloading a flammable liquids cabinet or breach the cabinets maximum storage capacity.
- Keeping chemicals inside robust containers with the lids in place.
- Wiping down the exterior of containers before placing inside the cabinet.
- Making sure nothing is protruding from the cabinet that could prevent the self-closing doors from shutting properly.
- Carrying out regular inspections of containers for cracks, holes and other leaks.
- Clearing the spill sump immediately after a leak or spill.
- If the cabinet has a vent bung near the spill containment sump, this bung must be tightly screwed into the vent ports.
Need some help choosing or installing a Class 3 Flammable Liquids cabinet? Please download our free eBook Essential Considerations When Storing Flammable Liquids Indoors. We explain the specifications of a compliant safety cabinet and demonstrate how to carry out a risk assessment to determine the specific dangerous goods storage requirements for your organisation. Download now by clicking on the image below: