If your organisation uses corrosive substances such as hydrochloric acid, sulfuric acid, sodium hydroxide or potassium hydroxide, it’s very important that you store and handle these dangerous substances in a way that minimises the risk they pose upon the people, property and environment of your organisation. Corrosive substances are very hazardous to human health because they have the ability to dissolve other materials through complex chemical processes. The Australian Dangerous Goods Code defines corrosive substances as:
Class 8 corrosive substances are substances which, by chemical action, will cause severe damage when in contact with living tissue, or, in the case of leakage, will materially damage, or even destroy, other goods or the means of transport.
Corrosive substances also release hazardous vapours that are very harmful to human health. If you inhale corrosive vapours, they will burn the lining of your nose, throat, windpipe and lungs. If you became exposed to high concentrations of corrosive vapours, it could result in pulmonary edema, which is a buildup of fluid in the lungs. If pulmonary edema is not treated, it can be fatal. To mitigate the risk of exposure to corrosive vapours, it's very important to ventilate all indoor cabinets that are used for the storage of corrosive substances. A compliant ventilation system for corrosive storage cabinets must comply with requirements outlined in AS3780-2008.
Ventilation requirements according to AS3780-2008
The Australian Standard that sets out the ventilation requirements for corrosive storage cabinets is AS3780-2008 - The storage and handling of corrosive substances. Section 6.2.4 of this standard states:
Wherever people are in an area where the corrosive substances are kept, adequate ventilation shall be provided. In addition, where the corrosive substance presents an inhalation hazard (of dusts, mists, fumes or vapours) and packages are opened, routine air monitoring shall be conducted to determine the level of airborne contamination. Where there is a significant level of airborne contamination, appropriate control strategies shall be implemented. NOTE: Workplace exposure standards also apply.
As this standard doesn’t state the a ventilation system “shall” be installed on an indoor safety cabinet, it means that it isn’t a mandatory requirement. However it does state that “wherever people are in an area where the corrosive substances are kept, adequate ventilation shall be provided”. Therefore if people work in the area where your corrosive substances are stored, its very important that you install a compliant ventilation system on your storage cabinets to keep the concentration of the corrosive vapours at a safe limit. Section 6.2.4 of AS3780-2008 also states that workplace exposure standards apply. Therefore if the concentration of corrosive vapours exceed the workplace exposure standard, a ventilation system must also be installed to keep the concentration of the corrosive vapours below the maximum limit specified in the workplace exposure standards.
Workplace exposure standards
Exposure to any kind of hazardous substances will pose significant health risk upon your workers. Some of these health risks include:
- Irritation to the eyes, ears and throat
To help combat these health risks, Safework Australia developed the workplace exposure standards. These exposure standards identify around 700 hazardous substances and their legal airborne concentration limits.
If the corrosive substances stored inside a corrosive storage cabinet are listed in the workplace exposure standards and the concentration of the vapours exceed the limit outlined in the standards, the corrosive storage cabinet will require ventilation. The ventilation system will reduce the corrosive vapours to a concentration safe for people to work in.
Features of a compliant ventilation system for corrosive substances
If you carry out a dangerous goods risk assessment and it is determined that your corrosive storage cabinets require a ventilation system, it’s important to install a ventilation system that will not pose any further risks to the people in your organisation. A safe ventilation system for corrosive storage cabinets must follow the requirements outlined below:
- A mechanical ventilation system should be designed so that it prevents any vapours from escaping into the room.
- The ventilation system shall be vented to the outside atmosphere in a location that is safe to disperse corrosive vapours. A safe location will be away from places where people congregate.
- The air inlet shall be attached to the vent port at the top of the cabinet and the corrosive vapours shall be extracted from the bottom vent port via the exhaust fan. This configuration is most effective as most corrosive vapours are heavier than air and reside in the bottom of the cabinet.
- A ventilation system cannot be linked to multiple cabinets. A ventilation system connected to multiple cabinets could cause vapours from incompatible dangerous goods to mix, resulting in violent chemical reactions.
- When a mechanical ventilation system is not attached to a cabinet, the vent bungs must be tightly screwed into the vent ports. This stops any corrosive vapours from escaping into the workplace.
- In all instances the ventilation system shall not compromise the structural integrity of the cabinet.
- In all cases the ventilation duct shall not be smaller than the size of the venting opening on the side of the cabinet. A ventilation system shall be designed by an appropriately qualified engineer and it shall comply with AS/NZS - 1668.2-2002
- The exhaust fan used to extract corrosive vapours from the cabinet must be corrosive resistant. This includes corrosive resistant blades and shrouds.
- The ventilation duct must be made from corrosive resistant material. Steel or galvanised pipes aren’t a good option as these materials are susceptible to corrosion. PVC piping is an excellent option as it is resistant to corrosion and easy to install.
- In all cases the diameter of the ducting should be no smaller than the vent opening on the cabinet.
As corrosive vapours pose severe health hazards upon the people of your organisation, it is good practice to ventilate corrosive storage cabinets to bring the concentration of corrosive vapours down to a safe working limit. For a ventilation system to be safe and compliant, it must follow the requirements outlined in AS3780-2008. For more detailed information on how to ventilate other dangerous goods storage cabinets such as those used to store flammable liquids and oxidising agents, download our free eBook by clicking on the image below 👇.