Acids and bases have many useful industrial applications, but if they aren’t treated carefully, they can destroy business property and harm human health. Acids and bases are classified as Class 8 - Corrosive Substances and they have the ability to damage other materials such as metal, stone and human flesh through complex chemical processes. Most corrosive chemicals are either acids or bases, however there are other hazardous substances that also have corrosive properties as a sub-risk to their predominate hazardous property such as flammability.
Acids are substances that have a pH level less than 7 and taste sour. On the other hand, bases have a pH level greater 7 and taste bitter. Acids will neutralise bases and bases will neutralise acids.
Some examples of acids include:
- Hydrochloric acid
- Sulfuric acid
- Nitric acid
Some examples of bases include:
- Sodium hydroxide
- Potassium hydroxide
- Ammonium hydroxide
Acids and bases pose many risks upon people and property and they must be stored and handled in a safe and compliant manner. We will now outline some practical measures that can be taken to reduce the risks that acids and bases pose upon people and property in the workplace.
Segregate acids from bases
Whenever acids and bases are stored in the workplace, it is very important to provide sufficient segregation between them. If acids and bases mix, it can result in violent neutralisation reactions. For example; if a strong acid such as hydrochloric acid mixed with a strong base such as sodium hypochlorite, it would result in a violent chemical reaction that would produce a lot of heat and gas.
2HCl (aq) + NaClO(aq) → Cl2 (g) + H2O (l) + NaCl (aq)
As you can see from the chemical formula, the mixing of these two acids and bases produces chlorine gas. Chlorine gas is very toxic and if it is inhaled, it can cause acute chlorine gas poisoning. Chlorine gas poisoning symptoms include breathing difficulties, nose and throat irritation, nausea and headaches.
During acid and base neutralisation reactions, the production of gases causes the corrosive solution to splash. If the splashes from the solution come into contact with your eyes or skin, it can easily result in acid burns and blindness.
To reduce the risk of acids and bases mixing, it is a good practice to store acids and bases in separate safety cabinets. If they cannot be stored in separate safety cabinets, acids and bases must be store in separate compartments within the cabinet. These separate compartments must also have separate spill containment compounds.
Segregate incompatible classes of dangerous goods
As well as segregating acids from bases, all corrosive substances, including both acids and bases, must be segregated from other incompatible classes of dangerous goods. There are nine different dangerous goods classifications and within these nine classifications, there are a number of classes that are incompatible with corrosive substances. Some of the incompatible classes include:
- Class 3 - Flammable liquids
- Division 4.2 - Spontaneously combustibles
- Division 5.1 - Oxidising Agents
- Division 5.2 - Organic Peroxides
If incompatible classes of dangerous goods mix, it can result in violent chemical reactions, that could produce explosions, fires and the rapid evolution of heat and toxic gases. Violent chemical reactions can cause injuries and a lot of property damage. To reduce the risk of violent chemical reactions, incompatible classes of dangerous goods must be segregated by certain distances outlined in the dangerous goods segregation chart, or stored in separate chemical storage cabinets. The required segregation requirements for incompatible classes of dangerous goods can be found by downloading our FREE dangerous goods segregation chart.
Store acids and bases in a compliant corrosive resistant storage cabinet
To ensure that you comply with the dangerous goods regulations, it is very important to store your acids and bases in a compliant corrosive resistant storage cabinet. The Australian Standard that outlines the requirements for the storage of corrosive substances is AS3780-2008 - The storage and handling of corrosive substances.
Section 4 of this standard outlines the design requirements for corrosive substance storage cabinets. These requirements include:
- Cabinets must have self-closing, close-fitting doors, held shut by catches at two or more points. The doors shall not open inwards, and shall be capable of being opened from inside the cabinet.
- The bottom of the cabinet must form a liquid-tight sump of least 150 mm deep and capable of containing at least 25% of the cabinets storage capacity.
- Any shelves within cabinets must allow for free air movement.
- The walls, floor, doors and roof of a cabinet shall either be constructed of corrosion-resistant materials or be protected by a corrosion-resistant lining or coating.
If acids and bases are stored in a cabinet that does not have these features, the cabinet will not comply with the regulations and you will be at risk of financial liability due to non-compliance.
The last design requirement provides the option for corrosive storage cabinets to be constructed from a corrosive resistant material or to be lined with a corrosive resistant lining. Because of this provision, there are two different types of corrosive resistant storage cabinets available on the market. If you are storing strong acids such as hydrochloric acid and sulfuric acid, it is better to use a cabinet that is constructed from a corrosive resistant material such as polyethylene. If you are storing weaker acids, they can be safely stored in a metal cabinet that has a corrosive resistant lining. However, if the lining of the cabinet gets chipped or scratched, the cabinet will start to corrode making the cabinet unsafe for the storage of corrosive substances.
Acids and bases are corrosive substances and they must be stored in a safe and compliant manner. When storing acids and bases in the workplace, it is very important that you segregate them and keep them away from other incompatible classes of dangerous goods. To avoid financial liability due to non-compliance, it is also important to store your acids and bases in a cabinet that has been designed and manufactured in full conformance to AS3780. 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.