NFPA 14:A.7.8 (2013) 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 appropriate 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 operations, hose friction loss could prevent the delivery of 100 psi (6.9 bar) to the nozzle. 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 11⁄2 in., 13⁄4 in., or 2 in. (40 mm, 44 mm, or 50 mm) hose in lengths of up to 150 ft (45.7 m). Some use 21⁄2 in. (65 mm) hose with a smooth bore nozzle or a combination nozzle. Some departments use 50 ft (15.2 m) of 21⁄2 in. (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. There is also Table A7.8 that indicates pressure requirements of common nozzle/hose arrangements. Duane Johnson, PE Program Manager Division of the Fire Marshal (Contractor) Office of Research Services National Institutes of Health 301-496-0487 "Protecting Science - One Sprinkler at a Time" -----Original Message----- From: Jim Davidson [mailto:[email protected]] Sent: Wednesday, February 19, 2014 11:26 AM To: [email protected] Subject: RE: 100 PSI requirement at top of Standpipe Rick and Brad, The original intent of NFPA 14 pre 1990's editions was to provide a 250 gpm hose stream for fire department use at the floor of fire department operations with a residual pressure of 65 psi flowing 250 gpm. This was based on high rise hose pack that the fire department were using which consisted of 2 1/2 inch hose, 100 ft pre-connected, with a non-automatic 2 1/2 inch Rockwood hose nozzle (solid/spray). With a residual pressure of 65 psi at the fire dept hose valve on the standpipe the Rockwood nozzle could throw a 250 gpm stream a minimum of 50 ft. At the One Merridian Fire the fire department high-rise hose pack consisted of 1 3/4 inch hose with 1 1/2 inch couplings, 100 to 150 ft of pre connected hose, with 1 1/2 inch, automatic Task Force nozzles. Actual testing after the fire indicated that the combination of 1 3/4 inch hose and automatic nozzle could not produce the 250 gpm flow that the old 2 1/2 inch hose and Rockwood nozzle combination could produce at 65 psi residual pressure at the fire dept hose valve. In some of the testing pressures in excess of 300 psi at the fire dept hose valve was required to produce a flow in the vicinity of 200 + gpm with the TTF nozzle and 1 3/4 hose combination. The designer of the standpipe system needs to discuss in detail with the appropriate fire department operations personal as to the real high-rise operations and hose stream deployment tactics actually used on the fire ground. The standpipe system was designed to NFPA 14 1984 Edition requirements as per City of Philadelphia requirements, at time the high rise pack consisted of 2 1/2 inch hose with Rockwood 2 1/2 inch nozzle. At time of fire the high rise pack consisted of 1 3/4 inch hose w 1 1/2 inch couplings, with 1 1/2 inch TFT automatic nozzles which completely changed the original intent of NFPA 14 to provide 250 gpm for fire hose stream operations and hydraulic requirements to produce the 250 gpm through the 1 3/4 hose. The standpipe system is a very important part of the fire departments operations at a high rise building and the fire department needs to be consulted about the fire ground operations SOP in order to address the particular high rise pack equipment used by the fire department and any unusual hydraulic requirements these operations introduce into the design of the standpipe system. Have a fire safe day! Regards Jim DAVIDSON ASSOCIATES Fire Protection Engineering P. O. Box 4010 Code Consultants Greenville, DE 19807-0010 Medical Gas Systems Engineering (302) 994-9500 Fax (302) 994-3414 CONFIDENTIALITY This report and any attachments are confidential and also may be privileged. If you are not the named recipient, or have otherwise received this report in error, please destroy the report, notify the sender immediately, and do not disclose its contents to any other person, use them for any purpose, or store or copy them in any medium. Thank you for your cooperation. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Matsuda, Richard Sent: Wednesday, February 19, 2014 10:45 AM To: [email protected] Subject: RE: 100 PSI requirement at top of Standpipe Brad, Here is my explanation of the 100-psi requirement, and I apologize to any one that I might offend with such a long opinionated response. This is my pet peeve, and I have tried my best to educate the fire service as to what they could expect during a high-rise fire condition. The old standpipe pressure requirement was 65-psi. This changed in the late 1980's or early 1990's after the One Merridian Place fire where two firefighters died whiile they were searching several floors above the fire. The lack of pressure avaiable in the standpipe allowed the fire to grow and extend to their search area. The standpipe system had PRV hose valves installed which were improperly adjusted to a pressure too low for fire operations. The NFPA-14 committee decided that since the automatic nozzles in use at that time required an optimum 100-psi nozzle pressure, that this magic number (100-psi) would be a good starting point. There was a long discussion with numerous tests of various nozzles and hoses. Too little pressure did not provided enough water and too much pressure made it very difficult to manuver the hose around corners. The minimum 100-psi at the hose valve was a "reasonable" pressure to allow "adequate" pressure to the nozzle while flowing a "sufficient" quantity of water taking into account different friction losses for different lengths and diameters of hose that the different fire departments would use. The maximum 175-pis was used to match the existing maximum pressure for the sprinkler systems connected to the standpipe, and also allow a range for minimum and maximum pressures that the PRV's could satisfy. Since then, numerous changes have been made in fire department operations. There are now low pressure automatic nozzles, low friction loss hoses, and many departments just use a non-automatic adjustable nozzle in their high-rise packs. Since the older buildings may only have 50 to 65-psi at the hose valve while the newer buildings have 100-psi, the manufacturers also have produced an in-line pressure gauge that can be installed at the hose valve so the firefighter can see the pressure available from the hose valve and make adjustments accordingly. Presently, it's really up to each AHJ to decide on an SOP for high-rise fires in their jurisdication knowing that the standpipe systems have pressures that can vary from 50 to 100-psi and may be equipped with pressure-restricting or pressure-reducing valves which may or may not be properly set. They need to pre-fire plan the buildings to learn how each building standpipe system was designed. rick matsuda city of dallas -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Brad Casterline Sent: Wednesday, February 19, 2014 8:51 AM To: [email protected] Subject: 100 PSI requirement at top of Standpipe Does anyone know why the technical committee settled on 100 PSI minimum at the 2.5" hose valve? It used to be 75 PSI, and for High Rise retrofit I have seen AHJs accept 75. I am just curious because I think with about 60 PSI at the 2.5" connection to the standpipe we could get about 250 GPM at the nozzle, figuring the Pf for the T, 2.5x0-6 nip, hose valve, and 100 feet of 2.5" hose. A 15 psi safety factor seems reasonable, but 40 psi??? I know the F.D. might want to use a 2.5x1.5 reducer and 1.5" hose, but with 150 GPM flowing through 100 feet of 1.5" hose the Pf in the hose alone is about 162 PSI! So, I don't get it, but I am likely missing some simple explanation, so I'm asking. thanks, Brad Casterline, NICET IV Fire Protection Division FSC, Inc. P: 913-722-3473 [email protected] www.fsc-inc.com _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler .org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
