Gas Cylinders

DISCLAIMER: The information provided below is not a substitute for hands-on and certified gas cylinder safety training. Do not attempt to move or tamper with gas cylinders or regulators unless you are qualified and trained to do so. The information presented below is by no means comprehensive – please consult the resources at the bottom of the page for more information.

Gas cylinders are used to supply the inert gas (nitrogen or argon) that is required to safely manipulate and handle air sensitive compounds and materials on a Schlenk line or in a glovebox. It is essential to be familiar with the safety aspects of gas cylinders and regulators prior to use.

Firstly gas cylinders must always be secured in place using a safety chain, belt or brace: cylinders are secured to the trolley during transportation and when in a fixed location, often against a wall fitted with a mounted cylinder bracket.

Gas regulators allow the gas pressure to be monitored and adjusted. During usual working operation, the gas regulator should not need to be adjusted. The cylinder valve allows the gas to enter the regulator, which typically has two gauges. The cylinder pressure gauge indicates how much gas is left in the cylinder and will therefore show when it needs to be replaced. The working pressure gauge shows the outlet delivery pressure of the gas, which is adjusted using the working pressure valve. If the gas cylinder is supplying inert gas to a single glovebox or Schlenk line, an additional outlet pressure valve may be placed before the tubing, and during day-to-day operation this is the only valve that should need to be adjusted. It is important to note that gas regulators have a limited lifespan and must therefore be assessed by a trained professional prior to use to ensure they are operating safely within the manufacturers recommendations.

A typical gas cylinder and regulator.

Gas cylinder banks containing two or more cylinders are commonly used to supply inert gas to multiple Schlenk lines or gloveboxes in a research lab. These will automatically switch to a secondary cylinder when the gas pressure falls too low. Cylinder banks have similar features to a typical gas regulator, but also allow the cylinders to be isolated from the system and can therefore be purged of air when a cylinder is replaced.

Useful Resources

BOC Guidelines for Gas Cylinder Safety

EPFL Laboratory Safety