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Fire
Protection Manual Chapter 4, testing procedures |
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Appendix 4: Gas Detection System Testing |
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1.0
Purpose
This document provides a procedure for
conducting periodic testing of a fire-detection device required by NFPA 72,
National Fire Alarm and Signaling Code®, Table 14.4.3.2 Device 17 (3).
2.0
Scope
This test shall be performed annually
on each gas detection system.
3.0
Planning
Notify
the facility work coordinator using the approved electronic work control
notification procedure. Allow one week for approval of the requested work; be prepared
to reschedule the requested work to satisfy the area’s production schedule.
Testing
requirements include:
·
2
staff members
·
4
hours of time
·
equipment
o
USIs
Two-Stage Alarm Gas Detector O & M Manual (see Section 8.0)
o
calibrated
thermometer
o
sensor
sample cape
o
pressure
regulator, set to flow 1.5 liters per minute
o
isolation
valve
o
approximately
4 feet of ¼-inch I.D. Tygon tubing
o
calibrated
Zero Span Gas
o
calibrated
50% LEL Methane Span Gas
4.0
Test Preparation
4.1
Establish
the fire detection system impairment using the Chapter 5, Fire
Protection System Impairment Procedure for detailed instructions on work
planning, advanced notification, and administrative controls.
4.2
Post
the Fire
Alarm Systems Testing in Progress sign(s).
4.3
Invite
the Technical Representative (TR) to witness the test.
4.4
Evacuate
the hazard area of unnecessary personnel.
4.5
Station
a knowledgeable technician at the Fire Alarm Control Panel (FACP) at all times
that the audible alarms are disconnected.
4.5.1
Disconnect
the building audible alarms at the FACP.
4.5.2
The
technician is to remain attentive at the FACP at all times that the audible
alarms are disconnected.
4.5.3
In
the unlikely event that an unanticipated fire alarm signal is received on the
FACP, the technician shall reconnect the building audible devices and join the
building evacuation.
5.0
Conduct the Test
5.1
Record
the detector’s serial number and location on the Gas Detector
Data Sheet.
5.2
Make
sure the instrument has been operating for a minimum of 30 minutes prior to
performing a calibration.
5.3
Determine
the ambient temperature in the sensor location
·
temperature
should be between 50ºF and 90ºF
·
calibration
is not accurate at temperatures below 50ºF
·
record
the temperature; be sure to annotate it on the calibration certification
5.4
Calibrate
Zero Span. Use sections of the Tygon
tubing to connect the:
·
outlet
on the Zero Span gas valve to the isolation valve
·
isolation
valve to the high-side of the pressure regulator
·
low-side
of the pressure regulator to the inlet marked on the sample cape
5.5
Observe
the inlet and outlet designations on the isolation valve.
5.6
Insert
the gas sensor into the sample cape, as shown in Figure I.
5.7
Fully
open the Zero Span gas cylinder valve.
5.8
Fully
open the isolation valve.
5.9
Wait
approximately 15 seconds then observe the VU meter indication.
·
It
is normal for the sensor to show a slight 'zero drift' while in operation.
·
If
the indication does not represent true zero, use the zero-potentiometer located
on the right-hand side of the controller to adjust the zero-baseline setting.
·
Record
the initial and adjusted readings on the calibration certification.
5.10
Fully
close the Zero Span gas cylinder valve.
5.11
Disconnect
the calibration tubing assembly from the cylinder outlet.
5.12
Adjust
to 50% Span.
5.13
Use
sections of the Tygon tubing to connect the
·
outlet
on the 50% LEL Methane Span gas valve to the isolation valve.
·
isolation
valve to the high-side of the pressure regulator.
·
low-side
of the pressure regulator to the inlet marked on the sample cape.
5.14
Observe
the inlet and outlet designations on the isolation valve.
5.15
Check
the VU meter.
·
Insert
the gas sensor into the sample cape, as shown in Figure I.
·
Fully
open the 50% LEL Methane Span gas cylinder valve.
·
Open
the isolation valve.
·
Allow
the calibration gas to flow across the sensor for approximately 15 seconds.
·
Observe
the VU meter indication.
o The meter should be stabilized
between 47% and 55%.
o If the reading is no more than 15%
outside of the high- or low-point of this range, adjust the Span potentiometer
on the right side of the controller to 50%.
·
Repeat
this procedure for each sensor to be tested.
5.16
If
the indication is outside of the +/- 15% tolerance, or if you are unable to set
the Span to 50%, proceed to the troubleshooting section (VIII) of the instrument’s
operational manual.
Note:
If the sensor is over 18 months old, it likely needs to be replaced. The
catalytic bead sensor is an organic device, which deteriorates over its
operational life in proportion to its exposure to gasses.
5.17
Fully
close the 50% LEL Methane Span Gas cylinder valve.
5.18
Disconnect
the calibration tubing assembly from the cylinder outlet.
5.19
Replace
all sensors to their original locations.
5.20
After
successful calibration, affix a current, dated, calibration sticker to the
controller housing, and a corresponding color-coded dot to each sensor tested.
5.21
Check
the high- and low-alarm settings.
5.22
Operate
the high- and low-alarm setpoint switches to the left of the VU meter and
verify alarms.
5.23
Verify
the setpoints against the factory settings for the original installation. These
settings should be recorded on the controller.
5.24
Record
high- and low-alarm setpoints on the calibration certification.
5.25
Observe
the condition of each detector for signs of mechanical damage, or anything that
may obstruct the sampling process.
5.26
Document
results on the Gas Detector
Data Sheet.
6.0
System Restoration
6.1
Reconnect
the building audible alarms at the gas alarm control panel.
6.2
Dismiss
the assisting technician at the gas alarm control panel.
6.3
Remove
the Fire
Alarm Systems Testing in Progress sign(s) previously posted.
6.4
Notify
the TR that tests are complete and the system is on-line and operational.
6.5
Allow
the TR to verify that the system is in normal operating condition.
6.6
Notify
personnel that they may return to the area previously designated as hazardous.
7.0
Conclusion
Upon completion of the procedure,
the gas detection system is on-line and operational.
8.0
References
·
USIs
Two-Stage Alarm Gas Detector O & M manual; CALIBRATION and MAINTENANCE Sections
·
NFPA
72, National Fire Alarm and Signaling Code
9.0
Revision History
|
rev |
summary |
date |
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1.0 |
triennial
review - updated - header and footer per discussion with T. Minga, 05.05.2022; - 9.0 per footer dates, as well as format of 9.0; - made general edits and format updates (e.g., bullets, spacing, etc.) - corrected
acronyms and abbreviations (e.g., SOTR to TR) - replaced previous
red-boxed links with more up-to-date red-outlined box links (see below) |
05.18.2022 |
|
0.2 |
periodic review; updated
author and Fire Protection Manager from E. Douberly to T. Minga |
06.02.2019 |
|
0.1 |
periodic review; minor edits |
06.02.2016 |
|
0.0 |
initial release |
06.15.2011 |
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ISSUING
AUTHORITY |
AUTHOR |
APPROVAL
DATE |
NEXT REVIEW
DATE |
rev |
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Fire Protection Department |
05.18.2022 |
05.18.2025 |
1.0 |
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