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95-8562
4.2
INTRINSICALLY SAFE CIRCUITS
Intrinsically safe installations require the use of suitable
and approved barriers, an approved fire alarm control
panel that is compatible with the barriers, and wiring
methods consistent with ANSI/ISA-RP12.6 and other
code. Appendix C calls out the type and quantity of
barriers required for installation in hazardous (classified)
locations and shows the electrical interconnection to an
NFPA compliant fire alarm control panel. Wiring that
passes from the non-hazardous location to the hazardous
location should pass through a seal appropriate for the
type of hazard. All control room instrumentation must
operate at less than 250 VRMS.
The barriers may be located in the main control panel or
in a separate enclosure, but adequate separation between
intrinsically safe and non-intrinsically safe wiring must be
observed as defined by ANSI/ISA-RP12.6. Barrier
grounds should be connected separately to the same
grounding location.
All initiating device wiring should be run in its own
separate raceway. Table 2 gives the maximum one way
wiring distances based on wire and barrier resistance. It
is also important not to exceed the maximum inductance
and capacitance listed on the intrinsic safety barriers.
This may restrict the maximum cable length to less than
the values listed in Table 2. Consult Appendix C for
further instructions.
AWG
(Solid)
Maximum One Way
Wiring Distance in Feet
(Excluding Integral Cable)
14-18
20
22
1000
600
400
NON-INCENDIVE CIRCUITS
In Class I, Division 2, Group A, B, C, & D locations, the
detector may be installed in non-incendive circuits. It is
also suitable for installation in Class II/III, Division 2,
Group F & G hazardous locations. Installations require
the use of an approved fire alarm control panel that is
compatible with the Class B, Style B and/or Class A,
Style D initiating device circuits. See Appendix D and E.
NOTE
ANSI/NFPA 70 (NEC) Article 501-4(b) requires the
use of enclosed gasketed wireways.
SYSTEM TEST
After the fire protection system is installed, it should be
tested for correct operation. The detectors may be tested
with live fires or by using the hand-held model PSS-MP
Test Set P/N 420116. The details of this sequence will
vary with particular installations, but the procedure must
include the following steps. See Appendix F.
PSS-MP Test Procedure
WARNING
A full system test results in an alarm output. This
will result in the automatic suppression system
being activated if it is not disabled prior to testing.
1.
Suppression System.
Disable the suppression
system if its activation is not desired during this test.
WARNING
Do not use the PSS-MP Test Lamp unless the area
is known to be non-hazardous.
2.
Fire Response Test.
Turn on the PSS-MP and wait
at least 15 seconds. Direct the beam into the front of
the detector to cause an alarm output. Hold the
PSS-MP so that the infrared filter is less than 1 inch
from the front of the flame detector to be tested as
shown in Figure 3. The control panel should indicate
an alarm condition at the detector under test. See
Appendix F for additional information.
Table 2—Maximum Wiring Distances
Figure 3—Testing a PM-5MPX with the PSS-MP Test Lamp
