Current through Register Vol. 54, No. 38, September 21, 2024
(a) An automatic
fire alarm system is a system designed to detect products of combustion and
provide automatic notification to all building occupants. It shall be composed
of detection devices, alarms, power source, wiring, and other related
components as necessary. All detection devices shall be listed as meeting U.L.
268, 1981 Edition.
(b) Automatic
detectors shall be installed to comply with the requirements of the applicable
occupancy division.
(c) Automatic
detectors shall be securely mounted on outlet boxes. Detectors shall not be
recessed into the mounting surface unless they have been tested and listed for
recessed mounting. Detectors may be ceiling or side wall mounted with a minimum
of 4 inches clearance from a ceiling to wall jointure measured from the
jointure to the top of the detector. Side wall mountings shall not exceed 12
inches measured from the ceiling and side wall jointure to the top of the
detector.
(d) Automatic detectors
shall be installed within the spacings or coverage used in the testing and
listing of the detectors by any of the accepted independent testing agencies.
The following considerations shall be made when determining spacing:
(1)
Smooth ceilings. Normal
spacings up to heights of 12 feet or less shall be used. Reduced spacing for
areas over 12 feet in height shall be used.
(2)
Sloped ceilings.
Detectors within 3 feet of the peak, measured horizontally, with additional
required detectors at normal spacings based on horizontal measurements shall be
used.
(3)
Beamed ceilings.
Beams over 8 inches in depth shall reduce normal detector spacings.
Beams over 18 inches in depth and on 8 feet or more centers shall have each bay
treated as a separate area requiring a minimum of one automatic
detector.
(4)
Partitions.
Partitions that extend to within 18 inches of the ceiling will not
influence detector spacing. Partitions less than 18 inches from the ceiling may
affect detection capabilities requiring reduced detector spacing.
(5)
Corridors. When spacing
detectors in corridors, the distance from the end wall of the corridor to the
first detector shall not exceed 1/2 of the maximum distance allowed between
first and second detectors in the corridor. The maximum distance allowed
between the first and second detectors in a corridor shall be based on the
spacing used when the detector was tested for listing by the accepted
independent testing agency.
(6)
Detector spacing for electromagnetic hold open devices. When
doors are held open by electromagnetic devices, automatic detectors shall be
installed at each location. A minimum of one automatic detector is required
when the distance from the top of the door to the ceiling is 24 inches or less.
Automatic detectors are required on both sides of the door when the distance
from the top of the door to the ceiling is over 24 inches. The mounting
distance of the automatic detector from the door shall not be less than the
distance measured from the top of the door to the ceiling with a minimum
distance of 12 inches and a maximum distance of 5 feet. The detectors may be
side wall or ceiling mounted with a preference for ceiling mounting. Approved
automatic closing devices with built-in hold open mechanism and detector may be
used in lieu of wall or ceiling mounted devices.
(7)
Special areas. The
Department may approve alternative spacing of automatic detectors in special
areas for specific hazards.
(e) Automatic fire detectors shall be
classified into one of the four groups as follows:
(1) Heat fire detectors are devices that are
designed to be sensitive to the rise in temperature produced by a burning
substance. Heat detectors are generally classified as fixed temperature
detection units, rate compensation detection units and temperature rate-of-rise
detection units.
(i) Fixed temperature
detection units may be the bimetallic, electrical conductivity, fusible alloy,
heat sensitive cable, liquid expansion or other approved types that will
respond when its operating element becomes heated to a predetermined level.
When automatic fire detection is required, fixed temperature detection units
shall be installed in boiler rooms, kitchens and other high heat or varying
temperature areas where the normal or occasional environment prohibits the use
of more sensitive fire detectors. The fixed temperature sensing setting shall
be commensurate with the area installed.
(ii) Rate compensation detection units are to
be considered for use in the same areas as required for fixed temperature
detection units.
(iii) Rate-of-rise
heat detection units may be the pneumatic spot-type or thermoelectric effective
type heat detection units that respond when the temperature around the unit
rises at a rate exceeding a predetermined amount. When automatic fire detection
is required, rate-of-rise heat detection units shall be installed in
lavatories, closets 25 square feet or less and other areas where the normal or
occasional environment would prohibit the installation of more sensitive fire
detectors. Rate-of-rise heat detection units may be installed with combination
fixed temperature elements.
(2) Smoke detectors are devices which detect
visible or invisible particles of combustion. Operating principles of smoke
detectors may be the photoelectric light scattering type, photoelectric light
obscuration type, projected beam type, ionization type utilizing radioactive
material, resistance bridge type or cloud chamber type. When automatic fire
detection is required, smoke detection units shall be installed in all occupied
and unoccupied spaces not protected with other type fire detectors or fire
suppression systems. Under certain hazards, the department may require smoke
detectors in addition to a fire suppression system. Smoke detectors may be
utilized as combination units with heat detectors or other fire detection
units.
(3) Duct mounted fire
detectors are devices designed to be sensitive to fire conditions in ducts
utilized for heating, ventilating, air conditioning or other purposes. Duct
mounted fire detectors may be classified as heat duct detectors or smoke duct
detectors.
(i) When an automatic fire
detection system is required in a building, air duct systems between 2,000 and
15,000 CFM shall have a heat detector installed at such a duct location that
the flowing fire temperatures will be sensed during all modes of operation of
the air duct system. Air duct systems over 15,000 CFM shall be equipped with
duct heat detectors and smoke duct detectors, installed at such duct locations
that the flowing fire temperatures will be sensed during all modes of operation
of the air duct system. Not less than one heat detector and one smoke detector
shall be installed in each system, additional detectors shall be added if
needed to sense all modes of operation.
(ii) A smoke duct detector shall be installed
in all ducts that penetrate a smoke barrier partition and connect to a smoke
damper for automatically restricting the spread of smoke in that particular
duct.
(iii) All duct mounted fire
detectors shall be connected to the building manual or automatic fire alarm
system. When a duct detector alarms, it shall automatically shut down its
associated supply fan and any associated smoke dampers to restrict the spread
of heat and smoke through the air duct system.
(iv) Ducts having an automatic extinguishing
system shall not be required to have heat or smoke duct detectors but shall
operate the fire alarm system, supply fans and dampers as described in this
paragraph.
(4) The
Department may require other detectors which would include fire detectors not
mentioned in the above classifications such as flame detectors, fire-gas
detectors or other fire detectors which are sensitive to a specific fire
related phenomenon.
(f)
Automatic fire alarm systems shall comply with §§
50.53,
50.55 and
50.56 (relating to general fire
alarm requirements; maintenance; and testing new equipment).
This section cited in 34 Pa. Code §
55.52 (relating to automatic
systems); 34 Pa. Code §
55.82 (relating to large personal
care homes); and 34 Pa. Code §
57.52 (relating to automatic
alarms).
