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13.7.4.1 General Requirements
13.7.4.1.1
The requirements of 13.7.4.1.1 through 13.7.4.1.4 shall apply to all initiating devices. [72:17.4.1]
13.7.4.1.2 Mechanical Protection
13.7.4.1.2.1
Initiating devices subject to mechanical damage shall be protected. [72:17.4.2.1]
13.7.4.1.2.2
If guards or covers are employed, they shall be listed for use with the initiating device. [72:17.4.2.2]
13.7.4.1.2.3*
The protection shall not prevent the initiating device from achieving the objectives of the system by adversely affecting the use, operation, or performance of the initiating device. [72:17.4.2.3]
13.7.4.1.3
Initiating devices shall be installed in a manner that provides accessibility for periodic inspection, testing, and maintenance. [72:17.4.3]
13.7.4.1.4
Initiating devices shall be installed in all areas, compartments, or locations where required by other governing laws, codes, or standards. [72:17.4.4]
13.7.4.1.5 Duct Detector Installation
13.7.4.1.5.1
Smoke detectors shall be installed, tested, and maintained in accordance with NFPA 72. [90A:6.4.4.1]
13.7.4.1.5.2
In addition to the requirements of 6.4.3 of NFPA 90A where an approved fire alarm system is installed in a building, the smoke detectors required by the provisions of Section 6.4 of NFPA 90A shall be connected to the fire alarm system in accordance with the requirements of NFPA 72. [90A:6.4.4.2]
13.7.4.1.5.2.1
Smoke detectors used solely for closing dampers or for heating, ventilating, and air-conditioning system shutdown shall not be required to activate the building evacuation alarm. [90A:6.4.4.2.1]
13.7.4.1.5.3
Where smoke detectors required by Section 6.4 of NFPA 90A are installed in a building not equipped with an approved fire alarm system as specified by 13.7.4.1.5.2, the following shall occur:
  1. Smoke detector activation required by Section 6.4 of NFPA 90A shall cause a visual signal and an audible signal in a normally occupied area.
  2. Smoke detector trouble conditions shall be indicated visually or audibly in a normally occupied area and shall be identified as air duct detector trouble.
[90A:6.4.4.3]
13.7.4.1.5.4
Smoke detectors powered separately from the fire alarm system for the sole function of stopping fans shall not require standby power. [90A:6.4.4.4]
13.7.4.2 Requirements for Smoke and Heat Detectors
13.7.4.2.1 Recessed Mounting
Unless tested and listed for recessed mounting, detectors shall not be recessed into the mounting surface. [72:17.5.1]
13.7.4.2.2* Partitions
Where partitions extend to within 15 percent of the ceiling height, the spaces separated by the partitions shall be considered as separate rooms. [72:17.5.2]
13.7.4.3 Location
13.7.4.3.1*
Unless otherwise modified by 17.6.3.2.2, 17.6.3.3.2, or 17.6.3.7 of NFPA 72, spot-type heat-sensing fire detectors shall be located on the ceiling not less than 4 in. (100 mm) from the sidewall or on the sidewalls between 4 in. and 12 in. (100 mm and 300 mm) from the ceiling. [72:17.6.3.1.3.1]
13.7.4.3.2
Unless otherwise modified by 17.6.3.2.2, 17.6.3.3.2, or 17.6.3.7 of NFPA 72, line-type heat detectors shall be located on the ceiling or on the sidewalls not more than 20 in. (510 mm) from the ceiling. [72:17.6.3.1.3.2]
13.7.4.3.3* Spot-Type Smoke Detectors
13.7.4.3.3.1*
Spot-type smoke detectors shall be located on the ceiling or, if on a sidewall, between the ceiling and 12 in. (300 mm) down from the ceiling to the top of the detector. [72:17.7.3.2.1]
13.7.4.3.3.2*
To minimize dust contamination, smoke detectors, where installed under raised floors, shall be mounted only in an orientation for which they have been listed. [72:17.7.3.2.2]
13.7.4.3.3.3
On smooth ceilings, spacing for spot-type smoke detectors shall be in accordance with 13.7.4.3.3.3.1 through 13.7.4.3.3.3.4. [72:17.7.3.2.3]
13.7.4.3.3.3.1*
In the absence of specific performance-based design criteria, one of the following requirements shall apply:
  1. The distance between smoke detectors shall not exceed a nominal spacing of 30 ft (9.1 m) and there shall be detectors within a distance of one-half the nominal spacing, measured at right angles from all walls or partitions extending upward to within the top 15 percent of the ceiling height.
  2. * All points on the ceiling shall have a detector within a distance equal to or less than 0.7 times the nominal 30 ft (9.1 m) spacing (0.7 S).
[72:17.7.3.2.3.1]
13.7.4.3.3.3.2
In all cases, the manufacturer's published instructions shall be followed. [72:17.7.3.2.3.2]
13.7.4.3.3.3.3
Other spacing shall be permitted to be used depending on ceiling height, different conditions, or response requirements. [72:17.7.3.2.3.3]
13.7.4.3.3.3.4
For the detection of flaming fires, the guidelines in Annex B of NFPA 72 shall be permitted to be used. [72:17.7.3.2.3.4]
13.7.4.3.3.4*
For solid joist and beam construction, spacing for spot-type smoke detectors shall be in accordance with 13.7.4.3.3.4.1 through 13.7.4.3.3.4.5. [72:17.7.3.2.4]
13.7.4.3.3.4.1
Solid joists shall be considered equivalent to beams for smoke detector spacing guidelines. [72:17.7.3.2.4.1]
13.7.4.3.3.4.2
For level ceilings, the following shall apply:
  1. For ceilings with beam depths of less than 10 percent of the ceiling height (0.1 H), the following shall apply:
    1. Smooth ceiling spacing shall be permitted.
    2. Spot-type smoke detectors shall be permitted to be located on ceilings or on the bottom of beams.
  2. For ceilings with beam depths equal to or greater than 10 percent of the ceiling height (0.1 H), the following shall apply:
    1. Where beam spacing is equal to or greater than 40 percent of the ceiling height (0.4 H), spot-type detectors shall be located on the ceiling in each beam pocket.
    2. Where beam spacing is less than 40 percent of the ceiling height (0.4 H), the following shall be permitted for spot detectors:
      1. Smooth ceiling spacing in the direction parallel to the beams and at one-half smooth ceiling spacing in the direction perpendicular to the beams
      2. Location of detectors either on the ceiling or on the bottom of the beams
  3. * For beam pockets formed by intersecting beams, including waffle or pan-type ceilings, the following shall apply:
    1. For beam depths less than 10 percent of the ceiling height (0.1 H), spacing shall be in accordance with 13.7.4.3.3.4.2(1).
    2. For beam depths greater than or equal to 10 percent of the ceiling height (0.1 H), spacing shall be in accordance with 13.7.4.3.3.4.2(2) (b).
  4. * For corridors 15 ft (4.6 m) in width or less having ceiling beams or solid joists perpendicular to the corridor length, the following shall apply:
    1. Smooth ceiling spacing shall be permitted.
    2. Location of spot-type smoke detectors shall be permitted on ceilings, sidewalls, or the bottom of beams or solid joists
  5. For rooms of 900 ft2 (84 m2) or less, the following shall apply:
    1. Use of smooth ceiling spacing shall be permitted.
    2. Location of spot-type smoke detectors shall be permitted on ceilings or on the bottom of beams
[72:17.7.3.2.4.2]
13.7.4.3.3.4.3*
For sloping ceilings with beams running parallel up slope, the following shall apply:
  1. Spot-type detector(s) shall be located on the ceiling within beam pocket(s).
  2. The ceiling height shall be taken as the average height over slope.
  3. Spacing shall be measured along a horizontal projection of the ceiling.
  4. Smooth ceiling spacing shall be permitted within beam pocket(s) parallel to the beams.
  5. For beam depths less than or equal to 10 percent of the ceiling height (0.1 H), spot-type detectors shall be located with smooth ceiling spacing perpendicular to the beams.
  6. For beam depths greater than 10 percent of the ceiling height (0.1 H), the following shall apply for spacing perpendicular to the beams:
    1. For beam spacing greater than or equal to 40 percent of the ceiling height (0.4 H), spot-type detectors shall be located in each beam pocket.
    2. For beam spacing less than 40 percent of the ceiling height (0.4 H), spot-type detectors shall not be required in every beam pocket but shall be spaced not greater than 50 percent of smooth ceiling spacing.
    [72:17.7.3.2.4.3]
13.7.4.3.3.4.4*
For sloping ceilings with beams running perpendicular across slope, the following shall apply:
  1. Spot-type detector(s) shall be located at the bottom of the beams.
  2. The ceiling height shall be taken as the average height over slope.
  3. Spacing shall be measured along a horizontal projection of the ceiling.
  4. Smooth ceiling spacing shall be permitted within beam pocket(s).
  5. For beam depths less than or equal to 10 percent of the ceiling height (0.1 H), spot-type detectors shall be located with smooth ceiling spacing.
  6. For beam depths greater than 10 percent of the ceiling height (0.1 H), spot-type detectors shall not be required to be located closer than (0.4 H) and shall not exceed 50 percent of smooth ceiling spacing.
[72:17.7.3.2.4.4]
13.7.4.3.3.4.5*
For sloped ceilings with beam pockets formed by intersecting beams, the following shall apply:
  1. Spot-type detector(s) shall be located at the bottom of the beams.
  2. The ceiling height shall be taken as the average height over slope.
  3. Spacing shall be measured along a horizontal projection of the ceiling.
  4. For beam depths less than or equal to 10 percent of the ceiling height (0.1 H), spot-type detectors shall be spaced with not more than three beams between detectors and shall not exceed smooth ceiling spacing.
  5. For beam depths greater than 10 percent of the ceiling height (0.1 H), spot-type detectors shall be spaced with not more than two beams between detectors, but shall not be required to be spaced closer than (0.4 H), and shall not exceed 50 percent of smooth ceiling spacing.
[72:17.7.3.2.4.5]
13.7.4.3.3.4.6
For sloped ceilings with solid joists, the detectors shall be located on the bottom of the joist. [72:17.7.3.2.4.6]
13.7.4.3.4 Air Sampling-Type Smoke Detector
13.7.4.3.4.1 General
13.7.4.3.4.1.1
In the absence of specific performance-based design criteria, each sampling port of an air sampling—type smoke detector shall be treated as a spot-type detector for the purpose of location and spacing in accordance with 17.7.3 of NFPA 72. [72:17.7.3.6.1.1]
13.7.4.3.4.1.2
Air sampling—type smoke detectors shall produce trouble signals if the airflow is outside the manufacturer's specified range. [72:17.7.3.6.1.2]
13.7.4.3.4.1.3
If provided, atmospheric contaminant filtration shall be listed for use with the detector and installed and maintained in accordance with the air sampling—type smoke detector manufacturer's published instructions. [72:17.7.3.6.1.3]
13.7.4.3.4.2 Pipe Network
13.7.4.3.4.2.1
Maximum air sample transport time from the farthest sampling port to the detector shall not exceed 120 seconds. [72:17.7.3.6.2.1]
13.7.4.3.4.2.2
Sampling pipe networks shall be designed on the basis of, and shall be supported by, computer-based fluid dynamics design calculations to ensure required performance. [72:17.7.3.6.2.2]
13.7.4.3.4.2.3
The sampling pipe network design calculations shall include pressure, volumetric flow, and alarm sensitivity at each sampling port. [72:17.7.3.6.2.3]
13.7.4.3.4.2.4
Software applications for the design of pipe networks shall be listed for use with the manufacturer's equipment. [72:17.7.3.6.2.4]
13.7.4.3.4.2.5
Sampling system piping shall be conspicuously identified as "SMOKE DETECTOR SAMPLING TUBE — DO NOT DISTURB," as follows:
  1. At changes in direction or branches of piping
  2. At each side of penetrations of walls, floors, or other barriers
  3. At intervals on piping that provide visibility within the space, but no greater than 20 ft (6.1 m)
[72:17.7.3.6.2.5]
13.7.4.3.4.2.6*
Sampling ports shall be identified as such. [72:17.7.3.6.2.6]
13.7.4.3.4.2.7*
If provided, test ports at the end (most remote location) of a pipe run installed in the pipe network solely for the purpose of validating consistency in performance (also referred to as benchmark test points) shall be included in the design calculations and allowed, but not required, to comply with the requirements of 13.7.4.3.4.2. [72:17.7.3.6.2.7]
13.7.4.3.4.2.8
If the piping and fittings are painted, the painting shall be performed in accordance with the air sampling—type smoke detector manufacturer's published instructions. [72:17.7.3.6.2.8]
13.7.4.3.4.2.9*
Pipe network materials, sizing, and installation shall be in accordance with the manufacturer's published requirements and suitable for use in the environment in which they are installed. [72:17.7.3.6.2.9]
13.7.4.3.4.2.10
Where used, capillary tubing shall be sized and affixed in accordance with the manufacturer's published instructions and computer-based design calculations. [72:17.7.3.6.2.10]
13.7.4.3.5* Projected Beam-Type Smoke Detectors
13.7.4.3.5.1
Projected beam-type smoke detectors shall be located in accordance with the manufacturer's published instructions. [72:17.7.3.7.1]
13.7.4.3.5.2
The effects of stratification shall be evaluated when locating the detectors. [72:17.7.3.7.2]
13.7.4.3.5.3
The beam length shall not exceed the maximum permitted by the equipment listing. [72:17.7.3.7.3]
13.7.4.3.5.4
If mirrors are used with projected beams, the mirrors shall be installed in accordance with the manufacturer's published instructions. [72:17.7.3.7.4]
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