15-16-370 Sprinkler piping.

   (a)   The sprinkler piping system shall consist of mains from the sources of sprinkler supply, risers, branches and sprinkler lines. Where a fire pump is a source of supply, it shall include the connection from the city main or other source to the suction of the pump. If a fire pump takes suction from any source except a city main, provisions shall be made which will prevent the entrance of any foreign or injurious matter to the system. There shall be no connection from the sprinkler system by which the supply in any other system might be contaminated. In addition to the sources of supply inside of the building, there shall be one or more siamese connections at points outside the building, in accordance with Section 15-16-390, connected directly to the main for the use of the city fire department.

   Sprinkler system components and hardware shall meet the requirements of NFPA 13-2013. All pipe fittings shall be designed to withstand the working pressure involved, but not less than 175 P.S.I. water pressure.

   Connected to the system main there shall be one or more independent system risers to supply all the sprinklers in the building or in each section of a building which is divided into sections by fire walls. They shall be securely fastened in place and adequately protected against mechanical injury and freezing.

   Each riser shall be of sufficient size to supply the greatest number of sprinkler heads served by it in any story. If an independent riser is provided to supply the sprinklers in a stair, or other tower, which is not provided with adequate fire stops between floors, such risers shall be of sufficient size to supply all heads in the tower.

   The size of connections from the water supplies to the system main shall be not less than the size of the largest system riser. The sizes of mains and distributing pipes shall be based on the following, except as provided in Section 15-16-600 of this code:

Size of Pipe in Inches	Maximum Number of Sprinklers
	Steel	Copper
1	2	2
1 1/4	3	3
1 1/2	5	5
2	10	12
2 1/2	20	25
3	40	45
3 1/2	65	75
4	100	115
5	160	180
6	275	300
8	400	425

 

   There shall be not more than eight sprinklers on a sprinkler line.

   Buildings having slatted floors or large unprotected floor openings without adequate fire stops shall be considered as one room.

   The sprinkler piping shall be so installed that there will not be any circulation in any portion of the system except that gridded or looped patterns of sprinkler piping may be used in hydraulically calculated sprinkler systems.

   Connections for purposes other than fire protection shall not be taken from any part of the sprinkler piping.

   When sprinklers installed above and below a ceiling are supplied from a common set of branch lines, such branch lines shall not exceed eight sprinklers above and eight sprinklers below the ceiling. The number of sprinklers fed by three-inch pipe and smaller shall be determined as per the following table:

Size of Pipe in Inches	Maximum Number of Sprinklers
	Steel	Copper
1	2	2
1 1/4	3	3
1 1/2	7	7
2	15	18
2 1/2	30	40
3	60	65

 

   Pipe larger than three inches shall be in accord with the previous table in this section, based on the larger count of sprinklers either above or below the ceiling.

   In occupancies listed in Section 15-16-230, piping supplying sprinklers may be sized according to the following table:

Size of Pipe in Inches	Maximum Number of Sprinklers
	Steel	Copper
1	2	2
1 1/4	3	3
1 1/2	5	5
2	10	12
2 1/2	30	40
3	60	65
3 1/2	100	115
4	Unlimited but system shall not exceed 52,000 square feet

 

   (b)   Effective January 1, 2018, the hydraulic calculation method shall be required, except the pipe schedule method shall be permitted for the following:

      (1)   Addition or modifications to existing pipe schedule systems.

      (2)   New systems of 5,000 ft2 or less.

(Prior code § 91-21; Amend Coun. J. 10-30-96, p. 31216, § 1; Amend Coun. J. 5-11-05, p. 47844, § 1; Amend Coun. J. 9-6-17, p. 55278, Art. VII, § 24)