ZONE LOW ZONE Water flow switch To HZ test header To LZ test header Fire hose valve
Water flow switch See Note 1
From water supply
Check valve with ball drip Fire department connection high zone Fire department connection low zone
FIRE PUMP HIGH ZONE GRADE LEVEL FIRE PUMP LOW ZONE
Note: Bypass in accordance with NFPA 20, Standard for the Installation
of Stationary Pumps for Fire Protection.
FIGURE A.7.1(d) Vertically Staged Pumps for Two-Zone System.
Check valve with ball drip HZ Drain valve
HZ Domestic water makeup Fire pump — high zone Pressure gauge Float valve MZ LZ LZ LZ Fire hose valve
Pressure gauge Fire
department connection— mid zone and tank fill
Fire department connection— low zone Lo w z one (LZ) Grade level LZ MZ MZ Drain valve See Note From water supply
Fire pump— mid zone Drain valve Waterflow switch Pressure gauge To test header
Note: Bypass in accordance with NFPA 20, Standard for the Installation
of Stationary Pumps for Fire Protection.
Mid z one (MZ) High z one (HZ) Pressure gauge MZ Fire pump— low zone Storage tank
The 200 ft (61 m) distance allowed for sprinklered build- ings could necessitate additional hose lengths in order to reach the most remote portion of a floor; however, automatic sprinklers should provide adequate control to allow time for fire fighters to extend hoses in those cases where a fire is lo- cated in the most remote area.
A.7.3.2.3 See Figure A.7.3.2.3.
A.7.3.2(5) Access to the roof can be via a stairwell that termi- nates at the roof level. Access could also be a permanent lad- der, permanent ladder rungs, or a pull-down stair with a roof hatch. See Figure A.7.3.2(5) for an example of roof outlets. A.7.3.3 Hose stations should be so arranged as to allow dis- charge to be directed from the nozzle into all portions of im- portant enclosures such as closets and similar enclosures. A.7.5 Fire department connections feeding interconnected standpipes, including combined systems, should be arranged to supply all interconnected standpipes in a building or sec- tion of a building. See Figure A.7.1(a), Figure A.7.1(b), and Figure A.7.1(c). Interconnection should occur as close to the source of supply(ies) as possible.
Standpipe systems in separate buildings or structures fed by the same water supply are not required to be interconnected. For example, a building might have an automatic-wet stand- pipe system while an adjacent parking garage has an automatic-dry standpipe system fed by the same fire pump and water main. These two standpipe systems are not required to be interconnected since they protect different structures. A.7.7.2 Hydraulic calculations should be provided to show that each fire department connection can adequately supply the standpipe demand.
A.7.8 Where determining the pressure at the outlet of the remote hose connection, the pressure loss in the hose valve should be considered.
It is very important that fire departments choose an appro- priate nozzle type for their standpipe fire-fighting operations. Constant pressure- (automatic-) type spray nozzles (see NFPA 1964, Standard for Spray Nozzles) should not be used for standpipe operations because many of these types require a minimum of 100 psi (6.9 bar) of pressure at the nozzle inlet to produce a reasonably effective fire stream. In standpipe opera- tions, hose friction loss could prevent the delivery of 100 psi (6.9 bar) to the nozzle.
Normally open Normally open Pressure switch Normally closed To fire department connection Normally closed Normally open Normally open Pressure switch
Note: FDC required downstream of pressure-regulating device but not required immediately adjacent thereto.
FIGURE A.7.2.4 Dual Pressure-Regulating Device Arrange- ment. X X X X X X Hose connection Hose connection Remote office
Maximum travel distance to a hose connection. FIGURE A.7.3.2(a) Location of Hose Connections in Stair- wells.
Horizontal exits Hose connections
FIGURE A.7.3.2(b) Location of Hose Connections at Hori- zontal Exits.
Exit passageway as required by other codes or standards
Fire department connection Hose connection
FIGURE A.7.3.2(c) Location of Hose Connections in Exit Passageways.
14–37 ANNEX A
In high-rise standpipe systems with pressure-reducing hose valves, the fire department has little or no control over hose valve outlet pressure.
Many fire departments use combination (fog and straight stream) nozzles requiring 100 psi (6.9 bar) residual pressure
at the nozzle inlet with 11⁄2in., 13⁄4in., or 2 in. (40 mm, 44 mm,
or 50 mm) hose in lengths of up to 150 ft (45.7 m). Some use
21⁄2in. (65 mm) hose with a smooth bore nozzle or a combina-
tion nozzle.
Some departments use 50 ft (15.2 m) of 21⁄2in. (65 mm) hose
to a gated wye, supplying two 100 ft (30.5 m) lengths of 11⁄2–2 in.
(40–50 mm) hose with combination nozzles, requiring 120– 149 psi (8.3–0.3 bar) at the valve outlet. (See Table A.7.8.)
Also see NFPA 1901, Standard for Automotive Fire Apparatus. A.7.8.1.2 It is not the intent of this standard to provide an auto- matic water supply for manual standpipe systems. Manual stand- pipe systems are designed (sized) to provide 100 psi (6.9 bar) at the topmost outlet using a fire department pumper as the source of flow and pressure.
A.7.9 Standpipe system zones are intended to limit system de- sign pressures to not more than 350 psi (24 bar) or within the system component pressure ratings as required by Section 7.2. It is the intent of Section 7.9 to provide for this pressure
Hose valve in stairwell covers the area on the other side of the horizontal exit.
No connection required at this side of the horizontal exit where the nearest connection covers the area on the other side of the horizontal exit.
FIGURE A.7.3.2.3 Location of Hose Connections at Horizontal Exits and Stairwells.