4.23 Combination Fire Services

Reference: 2007 CBC, Section 903, NFPA 13 2002, and NFPA 13R 2002

Combination fire services will be permitted only when the combined sprinkler system and domestic water demand through the meter will not exceed the manufacturer's listed maximum, intermittent delivery rate. The following guidelines will be used in conjunction with this policy:

Sprinkler System Design Criteria

Sprinkler systems supplied by the combination fire service must be hydraulically designed in accordance with NFPA 13D, 13R and/or 13 as required by the CBC, The Department of Building Inspection, and The Fire Department.
The domestic water demand must be included in the sprinkler flow at the domestic water system point of connection to the combination fire service line. Domestic water demand shall be at least 5 gpm per unit for two dwelling units or less. For three or more dwelling units, the domestic demand shall be as estimated using the Tables in NFPA 13R.
The maximum delivery rates for combination fire service are as follows:

1 inch service = 50 gpm
1-1/2 inch service = 100 gpm
2 inch service = 160 gpm

The meter friction losses to be used in the hydraulic calculations are:

DELIVERY RATE

Combination Fire Service Pipe

For all sizes, the service line must be copper (Type K with brazed joints) from the meter to the sprinkler connection to minimize problems of tuberculation.