Excerpted from Workplace Safety and Health Guidelines – Laboratory Handling Chemicals
Storage of Gaseous Chemicals
Chemical gases are typically stored in a compressed gas cylinder. Common gases used in a laboratory include: air, oxygen, nitrogen, carbon dioxide, nitrous oxide, chlorine, ammonia, methane, acetylene, and helium.
Compressed gas cylinders pose both a chemical and physical hazard. As each cylinder contains large amounts of stored energy and may contain a highly flammable/ toxic substance, compressed gases can potentially create a hazardous environment. If the valve of a gas cylinder were to break off, not only will the chemical gas escape, but the force of its quick expansion could propel the cylinder a few meters away from its original location.
Primary storage concerns:
- Keep gas cylinders away from heat sources, physical damage and tampering; and
- Keep chemical gases away from incompatible gases.
The following applies when storing gas cylinders:
- Keep stocks of gas cylinders to a minimum and within SCDF guidelines;
- Ensure that the each gas cylinder is clearly labelled to indicate its contents prior to storage. It is also good practice to label each cylinder as “FULL”, “IN USE” or “EMPTY”;
- Good practice is to store gas cylinders in an upright position on a floor rack or in a locked cage (to prevent unauthorized access and tampering) placed outside the laboratory in a cool and well-ventilated area, away from direct sunlight, heat sources and corrosive substances (see Figure 13). The required gases can be piped into the laboratory work area when necessary;
- Secure all gas cylinders (whether empty or full) to prevent them from falling over and damaging the valve (or falling on a person). Gas cylinders can be secured in an upright position by chaining or fastening them to a wall bracket or other fixed support;
- Store cylinders by gas type, separating incompatible gases from one another (e.g., separate oxygen/ oxidising agents from flammable gases). Separation can be achieved either through safety distance or using a fire wall;
- Ensure each gas cylinder’s main valve is easily accessible, so that the gas supply can be shut off immediately in an emergency;
- Wherever practicable, install a water sprinkler system over the storage area for gas cylinders so that the water spray will keep the cylinders cool in a fire. A system that automatically releases a suitable extinguishing agent over the cylinders may also be deployed where feasible;
- If a gas cylinder is no longer in use, shut its main valve, remove the pressure regulator and put its safety cap back in place to protect the valve prior to storage; and
- Mark all gas cylinders that are empty and store them separately from cylinders that are full or still in use.