If your organisation uses organic peroxides in a manufacturing process, it’s very important that you store and handle these dangerous goods in a way that minimises the harm that they pose to the people and property of your organisation. Safe storage and handling practices are a necessity as organic peroxides have many dangerous properties. These dangerous properties are outlined in the definition of organic peroxides given by the Australian Dangerous Goods Code. The definition is:
Division 5.2 Organic Peroxides are organic substances which contain the bivalent -0-0- structure and may be considered derivatives of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. Organic peroxides are thermally unstable substances, which may undergo exothermic self-accelerating decomposition. In addition, they may have one or more of the following properties:
- be liable to explosive decomposition;
- burn rapidly;
- be sensitive to impact or friction;
- react dangerously with other substances;
- cause damage to the eyes.
As outlined in the definition above, organic peroxides are thermally unstable substances and they may undergo exothermic chemical decomposition. When a substance undergoes chemical decomposition, the single chemical compound breaks down into two or more simpler chemical compounds. The simpler chemical compounds that are produced from chemical decomposition can sometimes be toxic or flammable gases. These toxic or flammable gases can have severe effects upon the people and property of your organisation. Flammable gases have the risk of causing uncontrollable fires and toxic gases are harmful to human health when inhaled.
When organic peroxides undergo exothermic chemical decomposition, they produce heat. This heat can accelerate the chemical decomposition reaction. When the heat energy produced from the chemical decomposition reaction is greater than the heat removal, it will cause the organic peroxide to undergo self-accelerating decomposition. This process can cause the organic peroxide to explode, harming people and property.
The risk of being harmed from inhaling dangerous gases and from explosive decomposition can be controlled by installing a ventilation system on organic peroxide storage cabinets. A ventilation system will remove the toxic, flammable and corrosive gases and maintain a consistent temperature inside the cabinet. A consistently low temperature is critical for avoiding the risk of explosive decomposition. The standard that outlines the requirements for ventilating organic peroxides storage cabinets is AS 2714-2008. We will discuss the requirements of this standard in more detail below.
Ventilation requirements according to AS 2714-2008
The Australian Standard that sets out the ventilation requirements for organic peroxide storage cabinets is AS 2714-2008 - The storage and handling of organic peroxides.Section 4.6 of this standard states:
4.6 ADDITIONAL REQUIREMENTS FOR INDOOR STORAGE CABINETS
4.6.1 Cabinet design and construction
The following requirements apply:
(g)The cabinet shall be ventilated in accordance with Clause 4.5.2. Where the cabinet is vented to the atmosphere, ducting shall be designed to prevent back-pressure and shall be directed away from any ignition sources and areas where people congregate.
Clause 4.5.2 states:
A store for organic peroxides (other than for those requiring refrigeration, as covered by Clause 4.5.5) shall be provided with ventilation at high and low levels, in order to prevent the buildup of flammable or toxic vapours and to assist in maintaining an even temperature.
As this standard states that “the cabinet shall be ventilated” it means that ventilation of dangerous goods storage cabinets used for the storage of organic peroxides is a mandatory requirement. Therefore if you are using chemical storage cabinets for the storage of organic peroxides, they must be ventilated to reduce the concentration of dangerous vapours to a safe limit. This will reduce the risk of the flammable vapours coming into contact with ignition sources and workers from becoming intoxicated from the inhalation of toxic vapours. We will now discuss the features of a compliant ventilation system for organic peroxide storage cabinets.
Features of a compliant ventilation system for organic peroxides
When you install a ventilation system on an organic peroxide storage cabinet, it’s very important to ensure that your ventilation system doesn’t pose any further risks to the people and property of your organisation. A safe and complaint ventilation system for organic peroxide 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 and any possible ignition sources.
- The air inlet shall be attached to the vent port at the top of the cabinet and the dangerous vapours shall be extracted from the bottom vent port via the exhaust fan. This configuration is most effective as most dangerous 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 toxic and flammable 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
- In all cases the diameter of the ducting should be no smaller than the vent opening on the cabinet.
- If the organic peroxide being stored produces corrosive vapours, the exhaust fan used to extract the vapours must be corrosive resistant. This ventilation system will need to have corrosive resistant blades, shrouds and ducting.
- If the organic peroxide that is stored produces flammable vapours, the exhaust fan will need to be intrinsically safe.
As organic peroxides are thermally unstable dangerous goods, it's very important that organic peroxide storage cabinets are ventilated in a safe and compliant manner. The ventilation system will extract any toxic and flammable vapours and keep the temperature inside the cabinet at a consistently low level. For more detailed information on how to ventilate dangerous goods storage cabinets, download our free eBook by clicking on the image below.