If you use corrosive substances such as hydrochloric acid and sodium hydroxide, it’s important that you store and manage them in a way that poses the least amount of risk to the people, property and the environment of your organisation. One important factor that must be considered when storing corrosive substances is ensuring that they are kept well away from other incompatible classes of dangerous goods. Of the eight other classes of dangerous goods, there are some that react dangerously with corrosive substances and others that are incompatible. The Australian Standard that outlines the requirements for storing mixed classes of dangerous goods provides different definitions of substances that are incompatible and those that react dangerously.
Incompatible substances are those substances that are:
- Likely to increase risk to people, property and the environment when mixed or brought into contact with another substance.
- Listed in the Australian Dangerous Goods Code or NZS 5433 as being incompatible.
- Declared by the local regulatory authority as being incompatible
Substances that react dangerously
Substances that will react dangerously are those substances that react in a manner that directly creates a hazard due to the reaction:
- Producing an explosion
- Being violent
- Producing a potentially explosive combination of products
- Producing toxic vapours or gases; or
- Producing fire or rapid evolution of heat
Dangerous Goods segregation
Dangerous goods that are incompatible or will react dangerously with class 8 corrosive substances must be segregated during storage to avoid violent chemical reactions. These incompatible classes of dangerous goods can be safely segregated by storing them in separate chemical storage cabinets or outdoor dangerous goods stores. Storing class 8 corrosive substances and other incompatible substances in the same dangerous goods store must be avoided at all times. If you have to store corrosive substances with other incompatible substances in the same dangerous goods store, the substances must be segregated by certain distances. The required distances for segregating incompatible classes of dangerous goods are outlined in the Australian Standard AS3833-2007- The storage and handling of mixed classes of dangerous goods in packages and intermediate bulk containers. We will now discuss the compatibility of corrosive substances with other classes of dangerous goods.
Class 2.1 - Flammable gas / Class 2.1 Non-flammable Non-toxic gas
Flammable and non-flammable gases are incompatible with corrosive substances. These substances cannot be kept together during storage. If these substances have to be stored in the same dangerous goods store, they must be kept apart by at least 3 meters. Another risk that exists when storing dangerous gases and corrosive substances together is the risk of the corrosive substances corroding the gas cylinder. If the gas cylinder corrodes it could burst and become a flying projectile that could harm people and property.
Class 3 - Flammable liquids
Flammable liquids and corrosive substances are also incompatible. These substances must not be stored together. If these substances have to be stored in a common dangerous goods store, the flammable liquids and corrosive substances must be segregated by at least 3 meters.
Class 4.1 - Flammable solids
Flammable solids and corrosive substances may or may not be incompatible. To ensure that these substances don’t pose any further risk upon your workers, it’s important to check the compatibility of the two substances before storing them together. The compatibility of the substances can be determined by checking the safety data sheets for both substances. It is also good to speak to the supplier or manufacturer of the hazardous substances to get their advice on the segregation and storage for that particular substance.
Class 4.2 - Substances liable to spontaneous combustion
Spontaneously combustible substances and corrosive substances are incompatible classes of dangerous goods. To avoid any further harm to the people of your organisation, its best to store these substances in separate indoor chemical storage cabinets. If spontaneously combustibles and corrosive substances have to be stored in the same dangerous goods store, they must be kept apart by at least 3 meters.
Class 4.3 - Dangerous when wet
Dangerous substances which emit flammable gases when in contact with water may or may not be incompatible with corrosive substances. Just like flammable solids you must determine the compatibility of class 4.2 and class 8 dangerous goods by checking the safety data sheets for each substance. It is also good to seek advice from the supplier or manufacturer of the hazardous substance.
Class 5.1 - Oxidising agents
Oxidising agents and corrosive substances are incompatible. These classes of dangerous goods must not be kept together. If these substances have to be stored in the same dangerous goods store, they must be segregated by at least 3 meters. If corrosive substances and oxidising agents mix they can produce dangerous by-products that are harmful to human health. An example is when potassium permanganate and hydrochloric acid react. These two substances will release chlorine gas. If you breathe chlorine gas it will mix with the water in your lungs and produce acids. These acids will dissolve your lungs and stop you from breathing. Inhaling chlorine gas can result in death.
Class 5.2 - Organic Peroxides
Organic peroxides and corrosive substances are also incompatible. Storing these two substances together must be avoided at all times. If organic peroxides and corrosive substances have to be stored in a similar store, they must be segregated by at least 3 meters.
Class 6 - Toxic Substances
Just like class 4.1 and class 4.3 dangerous goods, toxic substances may or may not be incompatible with corrosive substances. Before storing toxic and corrosive substances together check the compatibility of each substance by consulting their safety data sheets.
Class 8 - Corrosive substances
Some corrosive substances are compatible and some will react dangerously, even though they are of the same dangerous goods class. For example, if you mix a strong base such as sodium hypochlorite with a strong acid such as hydrochloric acid, it will result in a violent chemical reaction. The reaction will produce excessive amounts of heat and chlorine gas. The rapid evolvement of chlorine gas causes the corrosive substances to splatter and boil putting people in the nearby area at risk. Chlorine gas is also very toxic and harmful to human health. Before storing two different corrosive substances together, it’s important to determine their compatibility by consulting the safety data sheet for each substances.
As corrosive substances will react dangerously with a number of other dangerous substances, it’s very important that you apply the rules of segregation when you are storing corrosive substances with other classes of dangerous goods. If you would like a free dangerous goods segregation chart to help identify which classes of dangerous goods require segregation, go ahead and download our free segregation chart by clicking on the image below 👇.