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Idiomas disponibles
Idiomas disponibles
It is not necessary to isolate intrinsically safe components before working on them
3 REPAIR OF INTRINSICALLY SAFE COMPONENTS
Do not apply any permanent inductive load to the circuit without ensuring that this does not
exceed the allowable voltage and current for the equipment in use.
Intrinsically safe components are the only ones that can be worked with while living in the
presence of a flammable atmosphere. The test apparatus shall have the correct classification.
Replace components only with parts specified by the manufacturer. Other parts can ignite
refrigerant in the atmosphere from a leak.
4 WIRING
Check that the wiring will not be subjected to wear, corrosion, excessive pressure, vibration,
sharp edges, or any other adverse environmental effects. The control will also take into account
the effects of aging or continuous vibration from sources such as compressors or fans.
5 DETECTION OF FLAMMABLE REFRIGERANTS
In no case will potential sources of ignition be used in the search or detection of refrigerant leaks.
A halide torch (or any other detector that uses a naked flame) will not be used.
6 LEAK DETECTION METHODS
The following leak detection methods are considered acceptable for systems containing
flammable refrigerants. Electronic leak detectors should be used to detect flammable
refrigerants, but the sensitivity may not be adequate or may require recalibration. (The detection
equipment must be calibrated in an area free of refrigerant). Make sure the detector is not a
potential source of ignition and is suitable for the refrigerant used. Leak detection equipment
must be set to a percentage of the LFL of the refrigerant and will be calibrated for the refrigerant
used and the appropriate percentage of gas confirmed (25% maximum). Leak detection fluids
are suitable for use with most refrigerants, but the use of chlorine-containing detergents should
be avoided, since chlorine can react with the refrigerant and corrode copper pipes. If a leak is
suspected, all open flames must be removed/extinguished. If a refrigerant leak that requires
brazing is found, all refrigerant must 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) will then be purged through the system before and during the brazing process.
7 REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs, or for any other purpose, conventional
procedures will be used. However, it is important that best practices are followed as it is in danger
of being flammable. The following procedure will be respected: eliminate the refrigerant; purge
the circuit with inert gas; evacuate; purge again with inert gas; open the circuit by cutting or
soldering. The refrigerant charge will be recovered into the correct recovery cylinders. The
system must be "flushed" with OFN for the drive to be safe. This process may need to be repeated
several times. No compressed air or oxygen will be used for this task. Flushing will be
accomplished by breaking the vacuum in the system with OFN and continuing to fill until working
pressure is reached, then venting to the atmosphere and finally going down into a vacuum. This
process will repeat until there is no refrigerant in the system. When the final OFN charge is used,
the system will be vented to atmospheric pressure to allow work to be carried out. This operation
is absolutely vital if brazing operations are to be carried out on the pipes.
Make sure the vacuum pump outlet is not close to any ignition source and that ventilation is
available.
8 LOADING PROCEDURES
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