5. MAINTENANCE
AND
INSPECTION
§åNo
ignition
sources
No
person
carrying
out
work in relation to
a refrigeration
system which
involves exposing
any
pipe
workthat contains
orhas contained
flammablerefrigerant
shall useany
sources
of ignition
insuch a mannerthat
it
maylead to therisk
of fireor explosion.All
possible
ignition sources,
including
cigarette smoking, should
be kept suficiently
far awayfrom the
site of installation,
repairing,
removing
anddisposal,
during whichflammable
refrigerant
can
possibly
bereleased
to thesurrounding
space. Priorto
work takingplace,
the area
around
the equipmentis
to besurveyed
to
makesure that thereare
no flammablehazards
or ignition
risks.
"No
Smoking"
signs
shall bedisplayed.
&Ventilated area
Ensure that
thearea
is inthe open
orthat it isadequately
ventilated
beforebreaking
into
the
system orconducting
any
hotwork.
Adegree ofventilationshall
continue duringthe
period
that thework
is carriedout.
Theventilation
should
safelydisperse
any
released
refrigerant and
preferablyexpel
it externallyinto
the
atmosphere.
&
Checks
to the
refrigeration
equipment
Where electrical
componentsare
being changed,they
shall
befit for thepurpose
and tothe
correct
specification.At
all timesthe
manufacturer's
maintenanceand
service
guidelines
shall
be followed.lf
in doubtconsult
the manufacturer'stechnical
department
for
assistance.
The following
checksshall
be
appliedto installations
usingflammable
refrigerants:
The chargesize
is inaccordance
with theroom
size withinwhich
the refrigerantcontaining
parts
are
installed;
The ventilationmachinery
and outletsare
operating
adequatelyand
are
notobstructed;
lf an indirectrefrigerating
circuit isbeing
used, thesecondary
circuit shall
be checked
for
the
presence
of refrigerant;
Marking
to theequipment
continues
tobe
visible andlegible.
Markings
andsigns
that are
illegible shall
becorrected;
Reirigeration
pipe
orcomponents
are installedin
a
positionwhere
they areunlikely
to be
exposed to anysubstance
which maycorrode
refrigerant containing
components,
unless
the
components
areconstructed
of
materialswhich
are inherentlyresistant
to being
corroded
or aresuitably
protected
againstbeing
so
corroded.
3
Checks
to electricaldevices
Repair
and maintenanceto
electrical
componentsshall
include
initialsafety
checks and
component
inspection
procedures.
lf a faultexists
that couldcompromise
safety, then
no
electrical
supply
shallbe
connected
tothe circuit
untilit
is satisfactorilydealt
with.
lf the
fault cannot
becorrected
immediately
butit is
necessaryto
continue operation,an
adequate
temporary
solutionshall
be
used.This
shall be reported
tothe
owner ofthe
equipment so allparties
are
advised.
lnitial safety
checks shall
include:
.
Thatcapacitors
are
discharged:this
shall bedone
in asafe
manner toavoid
possibility
of
sparking;
. Thatthere
no liveelectrical
components
andwiring
are
exposedwhile
charging,
recovering
or
purgingthe
system;
. Thatthere
is continuityof
earth
bonding.
17
18
5.
MAINTENANCE AND
INSPECTION
@ Repairs to sealed components
1) During
repairsto sealed components,all
electrical suppliesshall
be disconnectedfrom
the equipment
being worked upon
priorto
any removalof sealed
covers, etc. lf it
isabsolutely
necessary tohave an electricalsupply
to equipmentduring
servicing, thena
permanently
operating form of
leak detection shall be located
at the mostcritical
point
to
warn of a
potentially
hazardous situation.
2) Particular attentionshall
be
paidto
the followingto
ensure thatby
working onelectrical
components, ihe casing
is not altered in such away
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 sealsor sealing
materialshave not degradedsuch
that theyno longer serve
the
purpose
of
preventing
the
ingressof flammable atmospheres.
Replacement
parts
shall
be in accordancewith
the manufacturer'sspecifications.
N
OTE:
The use of silicon sealant
may inhibit the effectiveness of
some types of leak
detection equipment.
lntrinsicallysafe components
donot have tobe
isolated
priorto
working on them.
@
Repair
to intrinsicallysafe components
Do not applyany
permanent
inductiveor capacitance
loadsto the circuitwithout ensuring
that this willnot exceed the
permissible
voltage andcurrent
permitted
forthe equipment
in
use.
lntrinsically safe componentsare
the onlytypes that canbe
worked onwhile live
inthe
presence
of aflammable
atmosphere. The test apparatusshall
be atthe correct rating.
Replace components onlywith
parts
specified by the manufacturer.
Other
parts
may result
in the ignitionof refrigerant inthe atmosphere
froma leak.
@
Cabling
Check that cablingwill
not besubject to wear, corrosion, excessivepressure,
vibration,
sharp edges orany other adverse
environmental effects. The check
shall also take into
account
the efiects of agingor continual
vibrationfrom sources suchas compressors
or
fans.
§
Detection of
flammable refrigerants
Under no
circumstancesshall
potential
sourcesof
ignition beused in thesearching
for or
detection of refrigerantleaks. Ahalide torch
(orany
other detectorusing a
nakedflame)
shall not be used.
6
Leak detection methods
The following leakdetection
methods aredeemed acceptable forsystems
containing
flammable refrigerants.
Electronicleakdetectorsshall
beusedtodetectflammablerefrigerants,butthesensitivity
may not beadequate, or mayneed re-calibration.
(Detectionequipment
shall becalibrated
in a refrigerant-freearea.)
Ensure thatthe detector
isnot a
potentialsource
of ignitionand
is suitable forthe refrigerant used.Leak detection
equipmentshall be setat a
percentage
of the LFLof the refrigerantand shall becalibrated
totherefrigerantemployed andthe
appropriate
percentage
of
gas (25
%maximum)
is confirmed.
Leak detection
fluidsare suitable foruse with mostrefrigerants
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 leakis suspected, allnaked flames shallbe removed/
extinguished.
lf a
leakageof refrigerant isfound which requiresbrazing, all
ofthe refrigerant shallbe
recovered from thesystem, or isolated(by
means ofshut offvalves)
in
apart ofthesystem
remote from theleak. Oxygen freenitrogen
(OFN)
shallthen be
purgedthrough
the system
both before andduring the brazingprocess.
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