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of leak detection shall be located at the most critical point to warn of a potentially hazardous
situation. Particular attention shall be paid to the following to ensure that by working on elec-
trical components, the casing is not altered in such a way that the level of protection is affected.
This shall include damage to cables, excessive number of connections, terminals not made to
original specification, damage to seals, incorrect fitting of glands, etc.
• Ensure that the apparatus is mounted securely.
• Ensure that seals or sealing materials have not degraded to the point that they no longer serve
the purpose of preventing the ingress of flammable atmospheres.
• Replacement parts shall be in accordance with the manufacturer’s specifications.
Repair to intrinsically safe components
Do not apply any permanent inductive or capacitance loads to the circuit without ensuring that
this will not exceed the permissible voltage and current permitted for the equipment in use.
Intrinsically safe components are the only types that can be worked on while live in the presence
of a flammable atmosphere. The test apparatus shall be at the correct rating. Replace components
only with parts specified by the manufacturer. Other parts may result in the ignition of refrigerant
in the atmosphere from a leak.
Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration, sharp
edges or any other adverse environmental effects. The check shall also consider the effects of
aging or continual vibration from sources such as compressors or fans.
Detection of flammable refrigerants
Under no circumstances shall potential sources of ignition be used in the searching for or detec-
tion of refrigerant leaks. A halide torch (or any other detector using a naked flame) shall not be
used.
Leak detection methods
The following leak detection methods are deemed acceptable for all refrigerant systems:
• Electronic leak detectors may be used to detect refrigerant leaks but, in the case of FLAM-
MABLE REFRIGERANTS, the sensitivity may not be adequate, or may need re-calibration.
Detection equipment shall be calibrated in a refrigerant-free area.
• Ensure that the detector is not a potential source of ignition and is suitable for the refrigerant
used. Leak detection equipment shall be set at a percentage of the LFL of the refrigerant and
shall be calibrated to the refrigerant employed, and the appropriate percentage of gas (25 %
maximum) is confirmed.
• Leak detection fluids are suitable for use with most refrigerants but the use of detergents con-
taining chlorine shall be avoided as the chlorine may react with the refrigerant and corrode the
copper pipe-work.
If a leak is suspected, all naked flames shall be removed/extinguished.
If a leakage of refrigerant is found which requires brazing, all the refrigerant shall be recovered
from the system, or isolated (by means of shut off valves) in a part of the system remote from the
leak.
For appliances containing FLAMMABLE REFRIGERANTS, oxygen free nitrogen (OFN) shall then be
purged through the system both before and during the brazing process.
