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10.Repairs to sealed components
• During repairs to sealed components, all electrical supplies shall be disconnected from
the equipment being worked upon prior to any removal of sealed covers, etc.
• If it is absolutely necessary to have an electrical supply to equipment during servicing,
then a permanently operating form 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 electrical
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 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.
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.
11.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.
12.Cabling
• Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration,
sharp edges or any other adverse environmental effects.
• Check shall also take into account the effects of aging or continual vibration from
sources such as compressors or fans.
13.Detection of flammable 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 flame) shall not be used.
• Electronic leak detectors may be used to detect refrigerant leaks but, in the case of
flammable 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 also 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 containing chlorine.
• If a leak is suspected, all naked flames 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.
14.Leak detection methods
• Electronic leak detectors shall be used to detect flammable refrigerants leak, 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 confirmed.
• Leak detection fluids 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 flames 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.
9-EN
10-EN
