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Specialist's
are constructed of materials which are inherently
resistant to being corroded or are suitably protected
era-
against being so corroded.
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● Checks to electrical devices
to
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Repair and maintenance to electrical components
shall include initial safety checks and component
inspection procedures. lf a fault exists that could
compromise safety, then no electrical supply shall be
ny
connected to the circuit until it is satisfactorily dealt
uch a
with. lf the fault cannot be corrected immediately but it
is necessary to continue operation, an adequate
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temporary solution shall be used. This shall be
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reported to the owner of the equipment so all parties
are advised.
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lnitial safety checks shall include:
Prior
---That capacitors are discharged: this shall be done
ment
in a safe manner to avoid possibility of sparking;
o
--- That no live electrical components and wiring are
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exposed while charging, recovering or purging the
system;
--- That there is continuity of earth bonding.
Repairs to sealed components
During repairs to sealed components, all electrical
f
supplies shall be disconnected from the equipment
the
being worked upon prior to any removal of sealed
y
covers, etc. lf it is absolutely necessary to have an
y
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 potential-
ed,
ly hazardous situation.
ect
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
ations
not made to original specification, damage to seals,
incorrect fitting of glands, etc.
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● 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
d,
atmospheres. Replacement parts shall be in
accordance with the manufacturer's specifications.
Note :
sible
● The use of silicon sealant can inhibit the effective-
e
ness of some types of leak detection equipment.
Intrinsically safe components do not have to be
ed in
isolated prior to working on them.
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Repair to intrinsically safe components
Do not apply any permanent inductive or capaci-
s
tance loads to the circuit without ensuring that this will
not exceed the permissible voltage and current per-
anual
mitted for the equipment in use.
lntrinsically safe components are the only types that
can be worked on while live in the presenc of a
flammable atmosphere. The test apparatus shall be at
the correct rating.
Replace components only with parts spec 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 compres or
fans.
Detection of flammable refrigerants
Under no circumstances shall potential sour 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.
Leak detection methods
The following leak detection methods are deemed
acceptable for all refrigerant systems.
Electronic leak detectors may be used to detect
refrigrant leaks but, in the case of flammable refrigerants,
the sensitivity may not be adequate, or may need
re-calibration. (Detection equipment 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 appropri-
ate 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.
lf a leak is suspected, all naked 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. For
appliances containing flammable refrigerants, oxygen
free nitrogen (OFN) shall then be purged through the
system both before and during the brazing process.
Removal and evacuation
When breaking into the refrigerant circuit to make
repairs - or for any other purpose - conventional
procedures shall be used. However, for flammable
refrigerants it is important that best practice is followed
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