6. Hydraulically Designed Sprinkler Systems

1. (a) For a hydraulically designed sprinkler system having only one booster pump as permitted in 8.6 (b), two sets of hydraulic calculations shall be submitted for the following alternatives: 
1. with the booster pump operating, the required density over the entire design area shall be met, together with hose requirements; and 
2. with the booster pump out of service, the municipal water supply shall be capable of supplying the required density over the entire design area. Hose requirements need not be considered. 

 
2. When sprinklers are installed above and below a ceiling and such sprinklers are supplied from a common set of branch lines, the branch lines and supply shall be calculated as follows: 
1. to supply the hydraulically most demanding area either above or below when the ceiling is of noncombustible construction without unprotected openings and having a fire resistance rating of ½ h or greater, or 
2. to supply the hydraulically most demanding area both above and below when the ceiling is of combustible construction not meeting 6.1 (b) (i). The sprinkler system in the blind space above a combustible ceiling can be designed hydraulically according to the Light Hazard occupancy requirements.