1-4
Detectors/sensors are usually required or recommended underneath open loading docks or
platforms and their covers, and in accessible under-floor areas in buildings without basements.
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
unauthorized persons, and it is protected against the accumulation of windblown debris.
2. The space contains no equipment/structures (such as steam pipes, electrical wiring, ducts,
shafts, or conveyors) that could potentially ignite or conduct the spread of fire.
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
4 in
(10 cm)
Minimum
12 in
(30 cm)
Maxi mum
Never her e
Top of t he detect or
acceptabl e here
Side
wall
Accept abl e here
Ceiling
Not e:
Measurements shaown are to the
cl osest edge of the detect or.
4 in
(10 cm)
Figure 1-1. Wall and Ceiling Mounted Detector/Sensor
Continued on next page
Where to Place Detectors and Sensors,
Continued
Proper Locations
for Detectors
and Sensors
Note: Measurements shown are to the
closest edge of the detector.
To Next Page
Loading...
Need help?
General
