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E 0 Chapter 3 Sprinkler Systems GENERAL Sprinkler systems provide early fire control or extin- guishment, helping to mitigate the hazards for occu- pants and firefighters alike. Building codes, fire codes, and life safety codes specify when to provide sprinkler systems. These may be either locally writ- ten codes or adopted model codes such as the IBC, the, IFC, NFPA 1, NFPA 101, or NFPA 5000. In addi- tion, various sections of the OSHA standards require the installation of sprinkler systems. A widely accepted installation standard for com- mercial system design is NFPA 13, Standard for the Installation of Sprinkler Systems. Other standards include: NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Mobile Homes; and NFPA 13R, Standard for the Installation of Sprinkler Systems in Residential Occupancies up to and Including Four Stories in Height. Designers may also refer to NFPA 13E, Recommended Practice for Fire Department Operations in Properties Protected by Sprinkler and Standpipe Systems, although any given fire service organization may follow different standard operating procedures. There is some flexibility in portions of the sys- tem that may impact the fire service. This chapter provides guidance to designers so they may exer- cise this flexibility to benefit fire department opera- tions. Fire department connections for sprinkler systems are covered in Chapter 5. Standpipe sys- tems (which are often integrated with sprinkler sys- tems) are covered in Chapter 4. Sprinkler designers should also see Chapter 6 for additional guidance on fire alarm annunciation, and Chapter 7 for spe- cial coordination considerations about smoke con- trol systems. ZONING It is important for sprinkler designers and fire alarm designers to work together, especially in unusual buildings. The fire alarm system will often have an annunciator to indicate the location of the alarm to the fire department. Sprinkler piping arrangement will limit options for fire alarm annunciation of water flow signals. Coordination is essential to fur- nish the fire service with clear information on the fire or its location. 28 Sprinkler designers often think in terms of ceil- ing levels, since sprinkler piping and sprinkler heads usually are at ceilings or roof decks. However, alarm signals are reported in terms of their floor level to enable the fire department to respond to the correct floor during an emergency. Consider the situation of a building with two levels adjacent to a single level "high-bay" area. The first floor sprin- kler zone should include both the high bay area and the lower level of the two-level section because each of these areas shares the same floor. Meanwhile, the upper level of the two-story section should have its own zone, even if the piping it con- tains is on the same level as the high bay area. In buildings with standpipe systems, sprinkler systems are usually combined with them and fed by a single water supply. Sprinkler systems are fed from the bulk feed mains or from vertical standpipe risers. NFPA 13 requires that sprinkler controls remain independent of standpipe systems. Typi- cally, all sprinklers would be located downstream from a control valve that will not shut off any fire hose connections (Figure 3.1). This enables the fire department to shut off the sprinklers during the rare occasions when a sprinkler pipe fails, or the sprinklers are not controlling the fire. In this man- ner, hose connections remain available for manual fire suppression without losing pressure from the broken pipe, or the excessive number of activated sprinklers. In some situations, when a building does not include a standpipe system, NFPA 13 allows fire hose connections to be fed from sprinkler systems. In these cases, closing the sprinkler system valve would shut off the fire hose connections. In some cases, sprinkler systems are fed from two different standpipes or feed mains, in a "dual- feed" arrangement. Although this provides a hydraulic design advantage, NFPA 13 recommends against it to avoid confusion. If a designer chooses this arrangement (and the code official permits it), cross-reference signs should be provided at each valve. Each of these signs would indicate the loca- tion of the companion valve that feeds the same system. No single sprinkler system should be fed from three or more points, since the flow from a single sprinkler may not activate any of the flow switches. O %U Occupational Safety and Health Administration 144