Fire Protection Design Manual - Office of Construction and Facilities ...

September-2011
Note: Class B signaling line circuits (these are not initiating device circuits by definition)
are preferable for local building fire alarm systems because it permits the circuits to be
t-tapped and the allowable length of the circuits are not shortened. No clear advantage is
seen for running Class A circuits except where signaling line circuits are run between
building fire alarm control units. Where signaling line circuits are run between fire alarm
control units in separate buildings, fiber optic circuits are preferred because they are not
susceptible to damage from lightning strikes. Where Class X copper circuits are installed,
provide isolation modules that will ensure that only one building is lost (will not respond)
during any type of fault. Although desirable, it is not required that Class X circuits be run in
separate conduits from each other.
G. Analog addressable systems are encouraged where many smoke detectors are required to be
installed. These systems do not require the frequent sensitivity testing for smoke detectors
that the hard-wired systems require and the savings in testing will pay for the extra cost of
the system.
H. Fire alarm design shall include a single line riser diagram that denotes location and device
type.
7.3 Typical Operation:
A. Table 7.3 is provided to identify the typical operation required by the respective fire alarm
systems. A table similar to this should be added to the contract documents to indicate the
specific operation required of the system.
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