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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
tor the equipment in use.
lntrinsically 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.
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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 continua! vibration from sources
such as compressors or fans.
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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.
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LEAK DETECTION METHODS
The following leak detection methods are deemed acceptable for systems
containing flammable refrigerants. Electronic leak detectors shall be used to
detect flammable refrigerants, but the sensitivity may not be adequate, or may
need recalibration. (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 pipework.
lf a leak is suspected, all open flames shall be removed/extinguished.
lf 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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REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs - or for any other
purpose - conventional procedures shall be used. However, it is important that
best practice is followed since flammability is a consideration. The following
procedure shall be adhered to: remove refrigerant; purge the circuit with inert
gas; evacuate; purge again with inert gas; open the circuit by cutting or brazing.
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