I apologize if this has been discussed already, but I would like to clear
my own mind, if nothing else.

I can't recall a hydrant flow test, that I performed, where my pitot
pressure has been higher than the residual pressure on the test hydrant.  I
have received two tests in the last year from city water departments where
this has been the case.  I can't make sense of the physics.  This *should*
not be possible, correct?

I can dream up a scenario where it would happen, but essentially, the flow
test would have to be taken backwards, where the test and flow hydrants are
flipped, and someone is using a decent amount of water, either past the
test hydrant, or between the test hydrant and flow hydrant... It seems like
if this happens (if your pitot reading is higher than your residual
pressure), you should flip the flow and test hydrants and repeat the test.
Am I thinking about this correctly?  Has anyone else had this issue, and is
it addressed in NFPA anywhere (perhaps it should be, if it isn't)?  Of
course, one of the gauges could be bad as well (which is probably just as
likely, if not more so, than the hydrants being flipped).


Thanks for any help with this,
Skyler Bilbo
_______________________________________________
Sprinklerforum mailing list
[email protected]
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org

Reply via email to