Fire Protection Systems Standpipe Systems PDF

Fire Protection Systems • Chapter 15 OBJECTIVE 3 Describe the design and operation of a typical standpipe system. STANDPIPE SYSTEMS The practical height limit for firefighters to couple hoses together from street level, up stairways to the fire floor is 3 stories (14 metres). It is also near the l...

Fire Protection Systems • Chapter 15 OBJECTIVE 3 Describe the design and operation of a typical standpipe system. STANDPIPE SYSTEMS The practical height limit for firefighters to couple hoses together from street level, up stairways to the fire floor is 3 stories (14 metres). It is also near the limit at which a fire can be fought externally from ladders and snorkel equipment. Standpipe systems deliver firefighting water to higher levels in a building. The standpipe rises up the stairwell(s). At each floor level, provision is made for the connection of fire hoses. The firefighters need only to couple hoses to one of the valved outlets provided on the standpipe to get a water supply. The connections used are usually on the floor below the fire, allowing the fire to be safely approached from below. Most building codes accept the NFPA (National Fire Protection Association) Code 14, Standard for the Installation ofStandpipe and Hose Systems as an integral part of their fire system code. The following descriptions can be found in more detail in NFPA-14. Classes of Standpipe Systems There are three classes of standpipe systems: • Class I systems provide 65 mm hose and connections. These systems are intended for use by fire departments and those trained in handling heavy fire streams. • Class II systems provide 40 mm hose and connections. These systems are intended for use by trained personnel or by the fire department during initial response. Subject to approval of the local fire authority, a minimum 25 mm hose and connections can be used in class II service in light hazard occupancies. • Class III systems provide 40 mm hose stations, and 65 mm hose connections. These systems are intended for use by trained personnel to supply a larger volume of water for use by fire departments. The number and location of standpipes and equipment is dependent upon the use, occupancy, and construction of the facility. Provincial and local authorities govern the fire acts, codes, and regulations. In general terms, the number of standpipes and hose stations are the same for each class. In each building, and in each section of a building divided by fire walls, there must be standpipes and hose stations such that all portions of each story of the building are within 9 m of a nozzle attached to no more than 30 m of hose. Where a 25 mm hose has been approved in class II service, all portions of each story of the building must be within 6 m ofanozzle attached to no more than 30 m of hose. The standpipe risers are to be located in non-combustible, fire-rated stairwells. If it is not possible to locate all standpipes in fire-rated stairwells, then additional standpipes may be located in pipe shafts at the building interior column locations. For class I and III service systems, at least one 65 mm roof outlet connection shall be provided from each standpipe. Figure 10 illustrates a typical roof manifold system. 3rcf C/ass Edition 3 • Part A2 785 ?£• Chapter 15 • Fire Protection Systems Figure 10 - Typical Roof Manifold 65 mm hose valves equipped with caps and chains Fire hose - Awall-mounted circular hose rack with sufficient 65 mm rubber-lined hose shall be provided near roof manifold. Roof manifold Other types may also be used Valve floor stand with indicator Slab Concrete insert Fire standpipe Double pipe clamp Automatic ball drip Extend to nearest- open fixture or drain The hose connections to the standpipe for Class I service should be located in the stairwell. For class II service, the hose connection should be located in the corridor or space adjacent to the stairwell. For class III service, the DN 65 (NFS IVz} hose connection should be located in the stairwell, and the 40 mm hose connection should be located in the corridor or space adjacent to the stairwell. Where the building has a large area, the connections DN 65 (NFS Wz) and DN 40 (NFS P/2) for class III may also be located at building interior columns. Standpipes for risers of less than 30 m are usually DN 100 (NFS 4) pipe. If the riser is greater than 30 m, the pipe is usually DN 150 (NFS 6). Where a building has a high-level fire zone (i.e., floors more than 85 m above street level), then the riser to these higher floors is usually DN 200 (NFS 8). The water pressure at the topmost outlet of each standpipe should not be less than 450 kPa, with a flow rate in the system of 32 litres per second (L/s). If the flowing pressure at any hose valve outlet will exceed 690 kPa, then a pressure reducing system shall be installed to reduce the pressure, at the required flow, to no more than 690 kPa. Note: The abbreviations DN and NPS stand for diametre nominal and nominal pipe size respectively. 786 3rd Class Edition 3 • Part A2 Fire Protection Systems • Chapter 15 ^ Wet and Dry Standpipes There are two basic standpipe systems. A wet standpipe is one that is always filled with water. A dry standpipe is one that is normally dry and terminates at its base, outside the building, with a fire department connection. If a fire requires fire department participation, a pumper engine will connect to a nearby street hydrant and discharge water into the standpipe system through the fire department connection. The fire department connection is a special Y-piece, called a siamese connection, which allows two hoses to simultaneously feed the standpipe (as shown in Figure 1 1). A siamese connection is also provided on a wet standpipe system. Class II and class III systems must be connected to a wet standpipe system since the 40 mm hose system must have water available immediately. Figure 11 - Siamese Connection 3rd Class Edition 3 • Part A2 ^ 787 ?& Chapter 15 • Fire Protection Systems Figure 12 shows a schematic of a typical single zone system, while Figures 13 and 14 show systems for buildings with two fire zones. Figure 12 - Typical Single Zone Standpipe System ! Tank ] fmr i 0 m y) 4— Ul 0 ® co <f> 0g E x s^ m .£ u) tn 0) W T 00 Q. Q0.0. -0 -0 c c co vs 03 W Fire department ^t- co mm connection D- Q- rmr i mr i Grade From water supply Fire pump 788 3rd Class Edition 3 • Part A2 Fire Protection Systems « Chapter 15 f£ Figure 13 - Typical Two Zone Standpipe System Tank 168m MAXIMUM ^~~^~~~. High level zone mrr | mn ii Tank r~^ 84m I TTTT] 0 co Low level zone U3M- CO 0 ®w <- °? og 1^ x m.c (D as 0.0. CL.CI. -OT3 c c ro ro ww Fire department -d-<D ww tU connection Q-Q- -^— High level zone fire pump ^— Fire department connection From water supply Low level zone fire pump Alternate supply 3rd Class Edition 3 • Part A2 789 ?& Chapter 15 • Fire Protection Systems Figure 14 - Typical Two Zone Standpipe System with Vertical ly-Staged Pumps I Tank I .-?-'-. •i 168 m Maximum' fTTTT | High level zone "^ "'"^ Valve normally closed ^ NPS8 High level zone fire pump 84 m Maximum >, Q- Q: ^ Fire department Fire department connection >-M-I high zone Grade connection low zone -To water supply Low level zone fire pump 790 3rd Class Edition 3 • Part A2