Chapter 18. All audible notification appliances must provide the appropriate sound level throughout a building to ensure the occupants can hear
them. Two modes of alarm signaling exist: public mode and private mode.
While a hospital might call for the private mode, our example requires
For public mode signaling, audible notification appliances must have
a sound level of at least 15 decibels (dBA) above the average ambient
sound level or 5 dBA above the maximum sound level having a duration
of at least 60 seconds, whichever has the greater value, measured 5 feet
above the floor in the area served by the system.
Hopefully, the system’s designer has included enough horns in the
public spaces to meet this requirement. During the system acceptance
test, most authorities having jurisdiction will want the sound level measured using a calibrated sound level meter. If the technician thinks the
design will not meet the code criteria, he or she should promptly submit
a request for information. The design calls for the use of sounder bases
in each hotel bedroom, which will help to ensure the system will meet
the required sound levels in those rooms.
Bedroom notification appliances must use a 520-hertz signal and meet
either the sound level requirements mentioned above or 75 dBA measured
at the pillow level, whichever has the greater value.
While the designer has the primary responsibility to ensure the system
uses the correct notification appliances to meet the required sound level parameters, the installer needs to know what the code requires. The designer
also has the responsibility for the layout of the visible appliances. However,
the installer should know the following installation requirements apply:
• Wall-mounted appliances must be mounted so that the entire lens
is not less than 80 inches and not greater than 96 inches above the
• Where low ceiling heights do not permit wall mounting at a minimum
of 80 inches, wall-mounted visible appliances must be mounted within
6 inches of the ceiling. The room size covered by a strobe of a given
value shall be reduced by twice the difference between the minimum
mounting height of 80 inches and the actual lower mounting height.
Generally speaking, visible appliances manufactured and listed for
mounting on the wall may not be installed on the ceiling unless the par-
ticular visible appliance has received a specific UL listing for this purpose.
Chapters 12 and 23 provide the requirements for circuits that connect
the initiating devices and notification appliances to the fire alarm system
control unit. Three types of circuits are recognized: initiating device cir-
cuits, signaling line circuits and notification appliance circuits.
Installers need to review the requirements for each of these circuits
and the specifications to find out which circuit class the designer has
specified. To this point, the installer will have installed the system backbone with all circuits brought to the fire alarm control unit. The installer
will need training on the specific system manufacturer to ensure proper
control unit installation.
Although we have covered a lot of the code requirements for this
installation, we obviously have not covered them all. Every installer must
read the entire NFPA 72 2016, National Fire Alarm and Signaling Code.
Knowing the basic requirements outlined above should go a long way in
making a fire alarm system installation more efficient and effective.
MOORE, a licensed fire protection engineer, frequent
speaker and an expert in the life safety field, is a principal
member and past chair of NFPA 72, Chapter 24. Moore is
a vice president with Jensen Hughes at the Warwick, R.I.,
office. He can be reached at
7 LOCK Brady’s compact cable
padlock features a flexible, elongated cable in two length options that
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with either 20-cm ( 7. 87 in.) or 40-cm ( 15. 75 in.) steel cables. It is available as keyed different or keyed alike, in standard colors: red, blue, green
8 FIBER ADAPTER Siemon’s Gen2 (G2) Ruggedized LC adapter is a
for harsh environments. It
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with an aggressive locking nut positioned behind the
faceplate that can be tightened
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has ceramic alignment sleeves that provide a tighter tolerance for optimum core-to-core alignment when mating.
9 ENCLOSURE Allied Moulded Products Inc.’s wall-mount enclosure
assembly has nine push-button holes in the
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10 CAMERA Swann’s
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