Working with gas

All compressed and liquefied gases should be regarded as hazardous. All persons working with compressed liquefied gases should be aware of the hazards associated with the particular gas used. These may include one or more of the following:

• Compressed State - release of gases from the container may occur with considerable force
• Low Temperature - many gases are at a very low temperature when released (see section 16 - Cryogenics)
• Reactivity - some gases (eg chlorine, oxygen, ammonia) are highly reactive with other materials
• Flammability - the high concentration and pressure increases the hazard
• Toxicity - some gases such as ammonia and chlorine are toxic
• Oxygen Depletion - while the gas may not be toxic, gas released may displace oxygen and act as an asphyxiant

Managing hazards

Safe use in the lab

To detect leaks use a soap solution or a specific gas detector and never use a match.

Before closing the laboratory check all gas taps to see that they are properly turned off. Turn off all electric apparatus except flame or spark proof equipment so as not to provide an ignition source in case of an unrecognised leakage.

Safe handling of gas cylinders

Transport FULL gas cylinders ONLY when properly secured on a gas cylinder trolley. If a safety cap is in place around the valve it should not be removed. Accidents have happened when a safety cap is used and the cylinder has not been secured properly. The valve may break off when the cylinder falls and the valve hits something. The release of compressed gas can propel the cylinder with sufficient force to smash through several concrete walls.

Always secure gas cylinders with a safety chain.

• Do not use excessive force when connecting the cylinder to your equipment. Use only the spanners designed for gas cylinders.
• Remember - flammable gases, e.g. hydrogen, acetylene, have left-hand threads and nuts, which are notched on reducing valves, to indicate this fact.