Fire Alarm CH 3 Flashcards
pressure supervisory switches must indicate _______ from nominal preassure
10 psi
ionization-type smoke detectors are best suited to detect smoke particles having a size ______ in diameter
1 micton
ceiling mounted spot type heat detectors are installed so that the edge of the detector is at least _____ from the wall
4 inches
a smoke detector that has a laser particle counter is best suited for _________.
clean rooms
for level non smooth ceilings section 17.7.3.2.4.2(1) of NFPA 72 permits the smooth ceiling spacing of spot-type smoke detectors for beans or joists with depth up to _______ of the ceiling height
10 percent
Ionization type smoke detectors use a _______ means of detecting smoke particles
americium 241
vane or paddle type water flow switches can not be used on what type of system
dry pipe
a smoke detector is required in each beam pocket where the beam depths are greater than _____ of the ceiling height and the width between beams is equal to or greater than ______ of the ceiling height
10 percent
40 percent
NFPA 72 permits ______ to be used as a guide for smoke detector spacing on smooth and level ceilings
a 30 foot by 30 foot box
Which type of smoke detector works best in large open areas?
projected beam type
total coverage is defined by NFPA 72 but _________
required by building codes.
a room temperature switch is a ______________.
supervisory signal -initiating device
the time difference between the ceiling temperature and the sensing element reaching the same temperature is called?
thermal lag
on a slopping ceiling beams run up the slope and are 14 inches deep the average ceiling height is 15ft according to NFPA 72 the smoke detector spacing should be _________
smooth ceiling spacing
total coverage is _______nfpa 72 but ________ by building codes
defined, required
the most appropriate type of detection for a smoldering fire is a ________.
photoelectric or light scattering smoke detector
heat detectors should be selected to operate at leas _____ above the maximum expected ambient temperature in the protected space
20 degrees F
total coverage is __________ but required by building codes
defined by NFPA 72
waterflow switches are permitted to have a time delay or retard up to _______ seconds
90
typically 60 seconds but 90 seconds is amx
Water level Switches are a ______ initiating device
supervisory
total coverage includes inaccessible ________
combustible areas
the spacing of heat detectors on ceilings with joists is generally reduce by ____________>
half in the direction perpendicular to the joists
vane or paddle type switches are a ________ initiating device
alarm
a smoke detector that has a ________ is best suited for clean rooms
laser particle counter
valve supervisory initiating devices must initiate a supervisory signal within _________ revolutions of the hand wheel or _______ of the travel distance of the valve
2
1/5th
wall mounted spot type heat detectors are installed so that the top of the detector is _____ from the ceiling
4-12 inches
supervisory signal-initiating devices indicate a ________.
off-normal suppression system
what device is used to directly detect flames
radiant energy-sensing fire detector
rate of rise heat detectors usually operate when the temperature rise is ______ per minute
12-15 degrees
heat detectors located on a smooth ceiling that is 19 feet in height must be reduced by ________ of their listed spacing
64 percent
smoke detectors that detect smoke by reflecting light from smoke particles onto a sensor are called ________ smoke detectors
light scattering or photo electric
