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When testing a fire pump from the roof is there a calculation that is necessary to ensure that the flow test is accurate (given pipe sizes, elevation increase, etc)?
NFPA 25, 2014 handbook states that flowing from the roof in the explanatory material is somewhat acceptable (NFPA 25, 2014: 8.3.3.1.3). However, NFPA 20, 2013 A.4.20.3.4(2) has a sample hydraulic calculation sheet for sizing the test header when not using the table which appears to take into account items like friction loss, elevation, etc. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
3 Comments
Cliff
11/1/2019 01:38:47 pm
As long as your pressure readings are taken at the fire pump, no adjustment is needed. The only reading you should be taking at the roof is a flow reading and that is what it is. If the Fire Marshal is looking to confirm the pressure at the roof, that reading may also be taken but that is not part of a fire pump test.
Jeff
11/1/2019 03:10:52 pm
Cliff,
Cliff
11/4/2019 08:13:39 am
It is my understanding, and someone please correct me if I'm wrong, that the pipe size increase is intended to make sure that the test header piping can support testing the fire pump to 150% of the pump's rating. The increase is not necessary if you can prove hydraulically that the pipe size will work. You may find that you can't reach 150% of the pump's rating while flowing at the roof. You can check this by running a standard hydraulic calculation; flowing 1125 gpm through the standpipe system back to the fire pump. Leave a Reply. |
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