Simplex 4098 Applications Manual page 12

Where to Place Detectors and Sensors,
Proper Locations
Detectors/sensors are usually required or recommended underneath open loading docks or
for Detectors
platforms and their covers, and in accessible under-floor areas in buildings without basements.
and Sensors
Detectors/sensors may be omitted from combustible blind spaces when all of the following
conditions prevail:
1. The space is not accessible for storage purposes, it is protected against the entrance of
2. The space contains no equipment/structures (such as steam pipes, electrical wiring, ducts,
3. The floor over the space is tight.
4. Non flammable liquids are processed, handled, or stored on the floor above the space.
"Total coverage" as described in NFPA 72, is the definition of a complete fire detection system.
In some of the specified areas of coverage, such as attics, closets, under open loading docks or
platforms, a heat detector may be more appropriate than a smoke detector. Careful consideration
should be given to the detector manufacturer's instructions and the following recommendations in this
guide.
In general, when only one detector/sensor is required in a room or space, the detector/sensor should
be placed as close to the center of the ceiling as possible. Central location of the detector/sensor is
best for sensing smoke and/or fire in any part of the room. If a center location is not possible, it may
be placed no closer than 4 inches (10 cm) from the wall, or if listed for wall mounting, it may be
mounted on the wall. Wall mounted detectors/sensor should be located approximately 4 to 12 inches
(10 to 30 cm) from the ceiling to the top of the detector, and at least 4 inches (10 cm) from any
corner wall junction (see the figure below).
FigureTag FD4-709-01
unauthorized persons, and it is protected against the accumulation of windblown debris.
shafts, or conveyors) that could potentially ignite or conduct the spread of fire.
C e ilin g
A c c e p ta b le h e re
Note: Measurements shown are to the
N o te :
closest edge of the detector.
M e a s u re m e n ts s h a o w n a re to th e
c lo s e s t e d g e o f th e d e te c to r.
Figure 1-1. Wall and Ceiling Mounted Detector/Sensor
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a c c e p ta b le h e re
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1 2 in
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