
Now . . .
What Big Paulie is asking (if I read him right) is how do you pre-determin Pump Discharge Pressure (PDP) or what "Rule of Thumb" do you go by to get it when every stretch is (or may be) a different length and you don't know till you get the call what it will be.
Say all you used was a preconnect of a known length (say 200 feet) you now have everything you need to rough calculate PDP (NP, Hose lenght & type for friction loss, Nozzle type, etc) so you can say if you pull Pre-connect XYZ start it at 85 psi Pump to have 50 psi NP and ajust for elevation.
Now for FDNY (and a lot of other places) it just don't work that way. You have to grab the knob and pull till you get to the fire & then say O.K. I got 300 feet of hose on the ground (or as johnusn971 mentioned - look it up in your pre-plan documents enroute) but it is only now at the moment of arrival (or dispatch if you have a pre-plan) that you know the length of your pull - so how do you "rough guess" your PDP ?
Say for instance PDP = NP(50psi) + 10psi per 100 feet + 10psi per 10ft elevation. So you could quickly say that you needed a PDP of roughly 80psi for a 200 ft pull to the second floor of a "typical" residental home.
Thats what I think Big Paulie is after - so c'mon all you people that know how to do this a lot better than I do start filling in the blanks.
Take Care - Stay Safe
Stephen
FF/Paramedic
NOTE All numbers & calculations cited here are for illistration only and are in no way meant to indicate a true or workable formula !!
BTW Big Paulie - we use the pre-measured preconnects almost exclusivly in our area so we have the starting PDP pre-calculated so I'm sorry I can't give you a good "guestimation" rule.
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