ABSTRACT
For a typical ordinary hazard occupancy (metal working plant, laundry, bakery, parking garage, repair garage, retail establishment, etc.), regardless of the type of automatic water supply, the NFPA standard requires a 60-minute duration of water to supply the hydraulically designed demands of the automatic fire sprinkler system, plus 250 gpm for outside hoses used by the responding fire department. Most public water supply systems are designed with a dual purpose in mind: that is, to supply water for (domestic usage) drinking, sanitary, and industrial uses, and also to provide emergency water for fire hydrants and to supply fixed fire suppression systems (see Figure 7.1). Although the adequacy of a public water system cannot be taken for granted, it was noted years ago that in large cities which required a substantial volume of water for domestic purposes, there was usually adequate water provided in the same existing water supply to provide for fire emergencies. A fire pump may be required to boost city pressure to meet system demands, particularly for taller buildings.
