Gas safety guidelines

Our guidelines provide more thorough information about the use of compressed gas cylinders within University workshops and laboratories.

Anyone working with compressed gas cylinders should be familiar with these guidelines.

Compressed gas cylinders

Note: Gas cylinders must be secured to a wall or a movable object, preferably with an upper and/or lower restraining chain.

  1. All users of gas cylinders must know and understand the properties of a gas before using it (flammability, toxicity and chemical activity) and must establish plans to deal with any emergency situation that might arise during use.
  2. Users of compressed gas must ensure that they are familiar with the procedures recommended by the various suppliers and that the correct regulators and valves are used in the proper manner.
  3. The number of cylinders in a workshop or laboratory must be kept to a minimum to minimise the fire and toxic risk, and empty cylinders are to be removed promptly.
  4. Cylinders are painted in accordance with BS349 to indicate the gas contained therein but this should not be relied upon alone. Check the official stamping on the cylinder or its label.
  5.  The valve outlets for combustible gases are screwed left-hand and those for non-combustible are screwed right-hand to avoid the dangers that could arise by the interchange of cylinders during use.
  6. Gas cylinders in transit are to have the valve protection cap in position until the cylinder reaches its point of use and is secured in position.
  7. Flashback arresters must be fixed to all cylinders of flammable gas attached to a source of ignition.
  8. All cylinders must be secured in the cylinder storage area.
  9. Care should be taken to ensure that gas cylinders cannot be knocked over.
  10. Cylinders should not be lifted by the cap, dragged, slid along the ground or dropped.
  11. Cylinders should be transported by means of a suitable hand trolley chained at the top and bottom and then supported and then supported or secured in the vertical position. Free standing cylinders are not permitted. Gas trolleys must not be used as stands.
  12. Never move high pressure gas cylinders with regulators attached without first ensuring that the main valve is closed. 
  13. Cylinders of liquefied gas (e.g. ammonia, carbon dioxide, chlorine, nitrous oxide, acetylene) must be used vertically.
  14. Cylinder valves and regulators should be checked periodically by technicians using them.
  15. All main cylinder valves should be opened slowly to eliminate the possibility of compression heating causing and explosion within the regulator.  Connections to flexible pipe work should be made securely with 'jubilee' clips or a similar fastening.
  16. Gas cylinders should always be turned off at the main valve of the cylinder when not in use — do not rely on the pressure reducer to turn off the gas flow.
  17. The contents of a gas cylinder must never be discharged without the use of a pressure control valve. Uncontrolled admission of a compressed gas to glass apparatus could result in a serious explosion and so a safety valve device must be fitted between the reducing valve and such apparatus.  Additionally, a gas cylinder must never be discharged completely. A positive pressure of about 2 atmospheres should be left to discourage leakage of air into the cylinder
  18. A cylinder key should be kept with the gas cylinder
  19. The pressure in any piped acetylene system must never exceed 1.6 bar and the system must be fitted with a flame arrester. If other gases are involved non-return valves must be used. A heavy blow on an acetylene cylinder can ignite the contents as a result of adiabatic compression and the cylinder may explode sometime late if action is not taken immediately. Those responsible for the use of acetylene should be acquainted with the emergency routines to be followed should the cylinder start to warm up.
  20. Oil or grease will ignite explosively in the presence of compressed oxygen and thus cylinders and valves must never be greased and must be kept away from possible contamination.
  21. The too rapid opening of a valve on a hydrogen cylinder can cause ignition due to static electricity.

Document Control
Version: 1.0
Last Updated: Dec 2019
Next Review: Dec 2022
Approver: Associate Director, Health Safety & Wellbeing