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Hydraulically calculated sprinkler systems shall be acceptable. Pipe friction losses shall be determined by the Hazen and Williams friction loss formula. The design area shall be the hydraulically most remote area. All sprinklers shall discharge at a flow rate at least equal to the design density times the area covered per head. The equivalent pipe length method shall be used for all fittings, valves, strainers and any other parts.
The “C” factor in the Hazen and Williams formula shall be as follows:
Pipe | “C” Factor |
Unlimited cast or ductile iron | 100 |
Black steel (dry and pre-action systems) | 100 |
Black steel (wet and deluge systems) | 120 |
Galvanized | 120 |
Cement lined cast or ductile iron | 140 |
Copper | 150 |
The design densities and area shall not be less than the following:
Occupancy | Density | Area |
Class A and B | .10 GPM square feet | 1,500 square feet |
Class C, D and E | .12 | 1,500 square feet |
Class F, G and H with ceiling heights to 14 feet | .20 | 2,000 square feet |
Class F, G and H with ceiling heights over 14 feet | .25 | 2,500 square feet |
Class I and those occupancies listed in Section 15-16-240 | .30 | 2,500 square feet |
For dry pipe sprinkler systems the area of application shall be increased 30 percent.
In buildings with mixed occupancies the design density and area of application for the different occupancies shall be applied to each occupancy. In buildings of Class A, B, C, D, or E occupancy class those areas used for storage or building maintenance shop purposes shall be sprinkled on the basis of an industrial occupancy. Spaces used for heating, ventilation, and air conditioning equipment shall have a density of .15 GPM/square feet over an area of 1,500 square feet.
Sprinkler systems using sprinklers with discharge orifices other than one-half inch in diameter shall be hydraulically calculated.
A safety factor, not less than five pounds per square inch, shall be provided between the calculated pressure requirement of a system and the water pressure available in the city water main supplying a hydraulically calculated system. The available city water pressure shall be determined by a water flow test at the site of the building conducted within the previous 12 months. The factor of safety shall be applied to the city pressure which is available at a flow of 1,000 gallons per minute or the calculated flow required for the sprinkler system whichever is greater.
(Prior code § 91-44; Amend Coun. J. 10-30-96, p. 31216, § 1)
Sprinkler systems installed in residential units pursuant to Section 13-160-050(m)(3) shall be installed as follows:
(A) Sprinklers shall be installed in all rooms of each dwelling unit except in bathrooms less than 55 square feet in area, closets less than 24 square feet open, carports and porches, and attics, crawl spaces or other concealed spaces not used or intended for storage or living spaces.
Sprinklers shall be installed in entrance foyers and enclosed attached garages.
(B) Only sprinklers listed for residential occupancy shall be used.
(C) When the sprinkler system serves more than one dwelling unit and is equipped with a fire pump, the fire pump and all associated controls shall be located in a room which is accessible without passing through an individual dwelling unit. The room shall be identified as the fire pump room.
A fire pump supplying a system which serves more than one dwelling unit shall be equipped with a bypass not less than one and one-half inches in diameter consisting of two control valves positioned on either side of a check valve.
Each sprinkler system which serves more than one dwelling unit shall be equipped with a siamese connection conspicuously located on the street frontage. Such siamese connection may have one hose connection.
A fire pump which supplies a sprinkler system which serves more than one dwelling unit shall be equipped with a test valve located on the discharge side of the pump.
(D) Pipe shall comply with Section 15-16-370.
(Added Coun. J. 10-30-96, p. 31216, § 1)
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