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.
Reply
Jeff
11/1/2019 03:10:52 pm
Cliff,
Reply
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. |
Free SignupSubscribe and learn something new each day:
CommunityThank You to Our Top
October '20 Contributors!
Your PostThe ToolkitSprinkler Designer or Engineer?
Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more: Filters
All
Archives
January 2021
Daily
Daily discussions are open-ended fire protection, fire alarm, and life safety questions submitted anonymously for the benefit of sharing expertise and learning from other perspectives. Anyone can submit a question here:
Exam Prep2020 PE Prep Guide
(Available Now!) PE Prep Series
(Available Now!) 2020 PE Prep Series
Current Leaderboard (Click to enlarge) PE Problems
Visit July-October for daily Fire Protection PE Exam sample questions.
Solutions are posted the day after posting. Comment with your solutions, questions or clarifications. Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves. |