Acids are highly corrosive chemicals that have a pH level below 7. Acids are highly corrosive and they dissolve human flesh and destroy substances such as metal and stone. Acids will neutralise alkalis, turn blue litmus paper red and they also taste sour. In fact, the word acid originated from the latin word acidus/acēre which means sour.
Acids can exist in a number of forms such as pure substances (solids, liquids or gases) or as an aqueous solution. Acids that are used in industry are normally aqueous solutions. Some of the commonly used acids include:
- Hydrochloric acid
- Sulfuric acid
- Acetic acid
- Citric acid
The risks associated with acids
The highly corrosive nature of acids makes them extremely dangerous. Acids can cause harm to human health and they can destroy property.
If acids come into contact with your skin, they will cause severe burns and destroy body tissue. The extent of damage to body tissue from acid burns depends on the concentration of the acid and length of exposure.
Acids can also dissolve heavy duty materials such as steel, concrete and stone. If acidic substances such as sulfuric acid came into contact with a machine which is constructed of metal, the acid would cause the machine to corrode. If this corrosion is not controlled, the machine would cease to function, which could cost your organisation a lot of money.
To prevent harm to human health and damage to business property, acids must be stored in a safe and compliant manner. The requirements for acid storage are outlined below.
Acid storage requirements
To ensure that your organisation is protected from the risks associated with acids, all acids must be stored in full conformance to the requirements outlined in the Australian Standards. The Australian Standard that outlines the requirements for the storage of corrosive substances including acids is AS3780-2008 - The storage and handling of corrosive substances. This standard outlines the different requirements for indoor storage and outdoor storage of corrosive substances such as acids. Acids can be safely stored indoors using a compliant indoor safety cabinet. Compliant outdoor storage can be achieved with a chemical storage container that has been manufactured in full conformance to AS3780.
The ability of an acid to corrode another substance depends on the concentration of H3O+ ions in the aqueous solution. Acids with a higher concentration have a stronger ability to corrode other substances such as metal and stone. Because the strength of acids vary, there are indoor storage solutions available for both weak acids and strong acids. No matter whether acid storage cabinets have been designed for the storage of weak or strong acids, they must always meet the minimum requirements outlined in AS3780. These requirements include:
- The cabinets must be provided with self-closing, close-fitting doors that are held shut by catches at two or more points. The doors must not open inwards and they must be capable of being opened from within the cabinet.
- The cabinet must have a liquid tight sump that is at least 150mm deep and capable of containing at least 25% of the cabinets storage capacity.
- The shelves within the cabinet must allow for free air-movement within the cabinet.
Storage of weak acids
Corrosive storage cabinets that are used to store weak acids are normally made from metal and coated with a corrosive resistant lining to stop the acid from corroding the cabinet. If this corrosive resistant lining got scratched, the acid would start to corrode the cabinets metal construction. To give acid cabinets extra corrosion protection, PVC spill trays and sump liners are placed on the shelves and within the sump of the acid storage cabinets. An example of an acid storage cabinet that can be used for the storage of weak acids is shown below:
Storage of strong acids
When storing strong acids, you must use a cabinet that will withstand the highly corrosive properties of strong acids. Cabinets used for the storage of strong acids are constructed from high-density polyethylene. High density polyethylene is corrosive resistant and it won’t break down when exposed to strong acids. Cabinets used for the storage of strong acids shouldn’t have any components such as door-closers or latches that are constructed from metal. An example of a polyethylene corrosive storage cabinet is shown below:
Outdoor storage of acids
To reduce the risk that corrosive substance have upon people and property, large quantities of acids must be stored outdoors. In fact, AS3780 states that the maximum quantity of corrosive substances that can be stored in an indoor corrosive storage cabinet must not exceed 1000L.
Larger quantities of corrosive substances can be safely stored outdoors using a chemical storage container that has been manufactured in full conformance to AS3780. The design requirements for acid storage containers include:
- The materials used for the construction of outdoor acid storage containers must be corrosive resistant, or coated with a corrosive resistant lining
- The acid storage container must have sufficient natural ventilation to keep the concentration of corrosive vapours below the workplace exposure standards.
- The container must have a spill containment sump that is capable of holding at least 25% of the storage capacity of the container or the capacity of the largest container, whichever is greater. In all instances, the spill containment sump doesn’t need to be greater than 5000L.
An example of an outdoor acid storage container is shown below:
Acids have the ability to harm the health of workers and damage business property. To reduce the risk of harm to people and property, acids must be stored in a safe and compliant manner. The requirements for storing acids is outlined in AS3780. This standard outlines different requirements for indoor storage and outdoor storage of corrosive substances. To ensure that you comply with legislation, it is important that you first identify and assess your specific acid storage situation before implementing any solutions. If you would like more information on how to manage the risks associated with hazardous chemicals, download our FREE eBook by clicking on the image below.