Building Design and Construction Handbook - Merritt - Ventech!

WATER-SUPPLY, SPRINKLER, AND WASTEWATER SYSTEMS 14.61
tems (Fig. 14.19). In any case, the maximum area per floor to be protected by a
single riser is 52,000- 2 for light and ordinary hazard areas and 40,000- 2 for extra
hazard areas.
In high-rise buildings where standpipes and sprinklers are required a combined
standpipe/sprinkler system is normally used. In these situations there may be no
true system riser; rather, each floor is provided with a floor control valve (Fig.
14.20) consisting of a control valve, drain, test connection and flow switch. In this
configuration the individual floor control valves accomplish the function of the
system riser. An inherent advantage of using floor control valves is that individual
floors can be isolated so sprinkler system repairs on one floor do not reduce the
level of protection on another floor.
As a practical matter, when lying sprinkler piping out it is advantageous to
consider the pipe hanging arrangement. Where construction consists of joist construction,
mains should be run parallel to the joist channels. This accommodates
FIGURE 14.19 Single riser (left), manifold system with multiple risers (right).
FIGURE 14.20 Floor control valve. (Reprinted with permission from
NFPA 13, Installation of Sprinkler Systems, Copyright � 1996, National
Fire Protection Association, Quincy, MA 02269. This reprinted material
is not the complete and official position of the National Fire Protection
Association, on the referenced subject, which is represented only by the
standard in its entirety.)