What are the NFPA flushing rates for external (unburied or underground) pipes?
I believe that they should be the same flushing flows proposed for underground pipes as contemplated in NFPA 24
Than you,#Flushing Flow Rate
What is this piping feeding??
And why aboveground?
There is no comprehensive flushing procedure contained in the code. AWWA recommends flushing at a velocity of 2.5 ft/s. Take the length of the piping in feet and divide it by 2.5 to estimate the time for clean water to appear at the flushing end and double that flushing time to ensure larger objects have time to move down the piping and get flushed out. For example: 200 feet of pipe flushed at 2.5 ft/s would require 80 seconds for the clean water to reach the flushing end of the piping. Double that and flush for total of 190 seconds.
Flushing time: Thanks for sharing the flushing time calc. I will use this in the future. Should the final flush time be 160 secs?
Let me take out my slide rule...uhmm...yes 2 x 80 = 160 secs. I do not know how I made through the engineering curriculum at college. We had no calculators then just slide rules. LOL
Internal Use Only
No problem. It was my era as well.
Mike Gil, ARM, CSITMS
Supv Ops Supt Engineering
O: 785-575-6522 M: 785-249-0245
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