26 September 2006
New sprinkler systems protecting areas of 139 m (1,500 ft) and greater must be
designed using hydraulic calculations. Use of pipe schedule designs is strongly
discouraged for any sprinkler system. Required discharge densities and areas of
discharge operation are given in Table 4-1. Calculations must follow the format
of NFPA 13. Pipe friction losses and equivalent lengths of pipe for fittings and
valves must be in accordance with NFPA 13.
Note: Additions to existing pipe schedule systems may be designed using the
pipe schedule method, except for Navy projects.
The designer (a fire protection engineer) must provide hydraulic
calculations demonstrating that the design will provide an adequate water supply
for the fire extinguishing systems. Hydraulic calculations must be submitted no
later than the 35 percent design submission. Calculations must be based on
recent water flow test data.
In buildings protected by automatic sprinklers, sprinklers must provide coverage
throughout 100 percent of the building except as permitted by NFPA 13. This
includes, but is not limited to, telephone rooms, electrical equipment rooms,
boiler rooms, switchgear rooms, transformer rooms, and other electrical and
mechanical spaces. Coverage per sprinkler must be in accordance with NFPA
13, except that it must not exceed 21 square meters (225 square feet) for light
hazard occupancies or 12.1 square meters (130 square feet) for ordinary hazard.
Exception 1: Facilities that are designed in accordance with NFPA 13R,
Installation of Sprinkler Systems in Residential Occupancies up to and Including
Four Stories in Height and NFPA 13D, Installation of Sprinkler Systems in One-
and Two-Family Dwellings and Manufactured Homes.
Exception 2: Sprinklers may be omitted from small rooms in specific
occupancies in accordance with NFPA 101.
Strainers must be installed where water conditions warrant, or systems with
underground distribution piping flow velocities greater than 2.4 m/s (8 ft/sec).
Interconnection of Risers.
For facilities four (4) stories and taller, there must be a combination
sprinkler/standpipe riser in at least two stairwells that are interconnected on each
floor. Each floor control valve assembly for the sprinkler connection must include
a check valve. See Figure 4-1. The sprinkler system must be hydraulically
calculated using the most hydraulically demanding riser. The calculations must
not assume the use of both risers simultaneously.