Leak Testing

Leaks may develop in any part of a gas system, particularly at joints

Performing a leak test

  • always check for leaks when cylinders are assembled with equipment, prior to use
  • ensure the leak detect solution is compatible with the materials used in the equipment construction
  • incompatible solutions can lead to stress corrosion and cracking of the cylinder valve
  • oil based solutions, or those containing fatty acids, can ignite if they come in contact with oxygen.  For this reason soapy water or washing up liquid must not be used

Leak Testing

BOC recommends using:

  • BOC CFC-free Leak Detector Spray or
  • A solution of 1% Teepol HB7 solution in demineralised water.
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  • all equipment in a gas system must be checked for leaks after assembly and corrective action taken before use
  • check with the manufacturer to ensure the leak detect solution is compatible with any material they may come in contact with
  • the leak test solution should be applied to ALL joints
  • use a small quantity of dilute leak detect solution for effective leak detection
  • apply the leak detect solution to joints and any potential leakage points such as at the point of connection of the cylinder valve with the regulator
  • never apply leak test solution into a cylinder valve outlet
  • if there is any frothing the system should be immediately depressurised and the leak corrected
  • do not use the equipment until the leak has been rectified
  • ensure the area is dry by wiping with a clean lint free cloth after the check has been completed
  • once the leak has been rectified re-purge air from the system prior to use
  • if in doubt contact BOC on 1800 355 255

Regularly check for faults and leaks

  • hoses with leaks, cuts, burns or local surface damage should be replaced with new industry approved fitted hose manufactured to the standard BS EN 1256
  • examine the cutting or welding nozzle regularly and if it is becoming clogged replace with new or clean it in the manner described by the manufacturer's instructions
  • keep equipment clean. In particular oxygen regulators must be kept in a clean area when not in use
  • pay special attention to pressure regulators. If a regulator is defective replace it immediately
  • British Compressed Gases Association Code of Practice 7 specifies the recommended checks and replacement cycles for portable oxy-fuel gas equipment. Guidance note GN7 gives similar recommendation for other portable gas cylinder equipment

Please note:


Coiled hoses

Ensure that both hoses are of equal length.  Do not coil surplus hose around the cylinder or regulator or on the floor adjacent to cylinders in storage or use.

A fire in a coiled hose is very difficult to extinguish.  If you do have surplus hose, position it behind you to keep it clear of sparks.

Leaks around the cylinder valve spindle

Leakage around the spindle of the cylinder valve will be revealed by hissing and in the case of fuel gases, by a smell.

Do not use the cylinder and do not attempt to repair the leak. Move the cylinder to an area where the leak can disperse safely, label it and advise BOC.

BCGA website