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protection is affected. This shall include damage to cables, excessive number
of connections, terminals not made to original specication, damage to seals,
incorrect tting of glands, etc.
• Ensure that apparatus is mounted securely. Ensure that seals or sealing materials
have not degraded such that they no longer serve the purpose of preventing the
ingress of ammable atmospheres. Replacement parts shall be in accordance with
the manufacturer’s specications.
Note: The use of silicon sealant may inhibit the effectiveness of some types of leak
detection equipment. Intrinsically safe components do not have to be isolated prior to
working on them.
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 ammable atmosphere. The test apparatus shall be at the
correct rating.
• Replace components only with parts specied 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 take into account the effects of aging or continual vibration from sources such
as compressors or fans.
Detection of ammable refrigerants
• Under no circumstances shall potential sources of ignition be used in the
searching for or detection of refrigerant leaks. A halide torch (or any other detector
using a naked ame) shall not be used.
Leak detection methods
• The following leak detection methods are deemed acceptable for systems
containing ammable refrigerants.
• Electronic leak detectors shall be used to detect ammable refrigerants, but 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 conrmed.
• Leak detection uids are suitable for use with most refrigerants but the use of
detergents containing 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 ames shall be removed/ extinguished.
• If a leakage of refrigerant is found which requires brazing, all of 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. Oxygen free nitrogen (OFN) shall then be
purged through the system both before and during the brazing process.
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