sprinklernotes Acceptance Testing for Manual Dry Standpipes
“We have been contracted to provide a manual dry standpipe system for a six-level parking garage. There will be a horizontal 6-in. loop on the second level feeding four 4-in. vertical standpipes, each of which will extend from the first level to the sixth level. The sixth level is completely open with no roof. A fire department connection (FDC) will be provided in close proximity to an existing public fire hydrant. The system is calculated based on pulling water from an existing fire hydrant with a fire department pumper (rated 1,500 gpm at 100 psi). The fire hydrant provides 80 psi static and 78 psi residual while flowing 1,353 gpm. Calculations prove we can provide 500 gpm at 100 psi at the top of the most remote standpipe and simultaneously flow 250 gpm from each of the three remaining standpipes while utilizing only 59.5 percent of the available pressure. The fire department says we must test the system according to Section 11.5.2 of NFPA 14. The fire department will not, however, allow their pumper or personnel to assist with getting the test performed. Even if they did the whole process of flowing and measuring pressures and flows from four risers simultaneously seems like a logistical nightmare. The calculations prove the system will work very well. Also, the Contractor’s Material and Test Certificate for standpipe system NFPA 14, 2007 edition doesn’t address such a required test. This doesn’t seem necessary or practical. The system has been hydrostatically tested.” In response to your question, we have reviewed NFPA 14, 2016 edition as the applicable standard. Our informal interpretation is other approved means can be used to verify the system design by pumping into the fire department connection. Section 11.5.2 does allow for other approved means to be used to verify the system design, but traditionally if the AHJ requires this to be completed the fire department provides a pumper to complete this requirement. Even the examples provided in Annex A (Figures A.11.5.2(a), A.11.5.2(b), and A.11.5.2(c)) show fire department pumper being utilized. However, Figure A.11.5.2(c) provides an example of how the flow test can be conducted without a pumper engine. Without the booster pump from the fire department pumper, the pressures required per the hydraulic calculations cannot be achieved, but Section A.11.5.2 explains that does not mean the test is failed. Section A.11.5.2 states: Where using the method shown in Figure A.11.5.2(c), it is necessary to flow the system demand while observing the pressures at the FDC inlet and the hydraulically remote standpipe hose valve. While the standpipe test might indicate that a greater pressure is required at the FDC inlet than what was indicated in the hydraulic calculations, this is not necessarily a cause for failing the test. This greater pressure, if acceptable to the AHJ based on the ability of the fire apparatus to provide the additional pressure, should be incorporated into the standpipe sign required at the FDC by 6.4.5.2.2. If this is determined to be the path forward it should be discussed with the local AHJ, as stated in Section A.11.5.2 and a written agreement should be obtained before proceeding further with the project. If the AHJ does not approve of either of these methods, Section 11.5.2.1 does allow for the AHJ to waive the requirement of Section 11.5.2. Section 11.5.2.1 states: Where allowed by the authority having jurisdiction, the test required by 11.5.2 shall be permitted to be waived. If the AHJ does not provide a fire department pumper, does not accept the alternative means provided in Section A.11.5.2 as shown in Figure A.11.5.2(c), and does not waive the requirement per Section 11.5.2.1 then the only option left is to connect a portable pump of a capacity to provide the required flow and pressure to the FDC. There are a couple of items that should be noted on this topic. First, Figure 11.1.3(a), Sample Contractor’s Material and Test Certificate for Above Ground Piping does have a line for the flow test on the third page. It’s interesting that it references only the most remote standpipe, implying only a 500-gpm flow is required, but this is not actually the case. Also, the typical pressure used in hydraulic calculations from fire department pumpers operating at 1,500 gpm is 150 psi. The NFPA 14 Handbook commentary for Section A.5.4 states in most jurisdictions the standard operating procedure is to provide 150 psi. This should be taken into account when discussing whether an actual flow test is needed since the system only requires 100 psi, which is a significantly lower flow than standard operating procedure. The fact that a hydrostatic test has been performed shows that the integrity of the pipe is acceptable. This combined with the low inlet pressure for your calculations supports applying the waiver for not conducting the flow test as allowed by Section 11.5.2.1. Technical Update has been prepared by the Technical Services department of the American Fire Sprinkler Association (AFSA). Technical Updates are provided by Roland Huggins, PE, Senior Vice President, Engineering & Technical Services; Russ Bainbridge, PE, Senior Fire Protection Engineer; Jason Williams, CET, Manager of ITM Technical Training; and Tom Noble, CET, CFPS, Technical Programs Specialists. This is provided with the understanding that the AFSA assumes no liability for this opinion or actions taken on it and they are not to be considered the official position of the NFPA or its technical committees.
