Look in IFC Appendix B under Definitions: Fire-Flow. "The flow rate of water measured at 20 pounds per square inch residual, that is available for fire fighting."It's just a baseline for everything else. Water departments always reduce actual residual and flow from a pitot test to 20 psi so there is a consistant base of numbers.
On Wed, Aug 24, 2011 at 7:41 AM, Olie Olson <[email protected]> wrote: > The fire department requires a min pressure for their pumper trucks to > operate as designed. > The suction hose has pressure losses. > > > > Olie Olson, P.E. > Fire Protection Design > 406-860-3170 mobile > 406-628-2314 office > -----Original Message----- From: [email protected] > Sent: Wednesday, August 24, 2011 8:27 AM > > To: sprinklerforum@firesprinkler.**org <[email protected]> > Subject: RE: Minimum pressures in water supply; Why 20 psi? > > If <20 psi would collapse water lines, how do they remain intact when > empty? > > > > Craig L. Prahl, CET > Fire Protection > CH2MHILL > Lockwood Greene > 1500 International Drive > Spartanburg, SC 29304-0491 > Direct - 864.599.4102 > Fax - 864.599.8439 > CH2MHILL Extension 74102 > [email protected] > > > -----Original Message----- > From: > sprinklerforum-bounces@**firesprinkler.org<[email protected]>[mailto: > sprinklerforum-**[email protected]<[email protected]>] > On Behalf Of Smith, Steven D. (CSFD) > Sent: Wednesday, August 24, 2011 10:16 AM > To: sprinklerforum@firesprinkler.**org <[email protected]> > Subject: RE: Minimum pressures in water supply; Why 20 psi? > > During a sprinkler design class we were told by the instructor that the > 20psi comes from the health department and anything less than 20psi in the > mains will require citizens to boil the water to remove containments in the > water. Previously I had always heard anything less than 20psi could > potentially collapse water lines. > > Steve > > -----Original Message----- > From: > sprinklerforum-bounces@**firesprinkler.org<[email protected]>[mailto: > sprinklerforum-**[email protected]<[email protected]>] > On Behalf Of David de Vries > Sent: Wednesday, August 24, 2011 8:11 AM > To: sprinklerforum@firesprinkler.**org <[email protected]> > Subject: Minimum pressures in water supply; Why 20 psi? > > Does anyone know where the 20 psi minimum for undergound piping originated? > I have seen it in some state water regs, but have never been satisfied that > it is a sound, scientifically-based number. > > I have also seen fire dept SOP's set an alert on suction pressure at the > pumper to 5 psi. Depending on the hose lay, that might equate to 20 (or 10) > psi in the main. > > Dave > > David A. de Vries, P.E., CSP > Firetech Engineering Incorporated > > > --- On Wed, 8/24/11, Letterman, Todd <[email protected]> wrote: > > > From: Letterman, Todd <[email protected]> > Subject: RE: Minimum pressures in water supply > To: sprinklerforum@firesprinkler.**org <[email protected]> > Date: Wednesday, August 24, 2011, 8:27 AM > > > I agree with all who have responded and I'm not sure if there is hydrant > at the entrance to this place or along the street that could rob your > suction pressure. If there is a hydrant coming into the property, then > they are most likely going to start there hose lay at that point, which > may rob all the theoretical values so far. You are not going to have > much suction pressure at a 100%. If a fire takes it to that demand but > there is really nothing stating that you cant go lower than 20 unless > the water authority or other entity states other wise. It was never > stated if it is going to be a Electric or Diesel Driver or have you > gotten that far yet? > > Todd Letterman > Fire Prevention Engineer CFPS > Riverside County Fire Department "Fire never sleeps" > (951) 955-5273 FAX (951) 955-4886 > [email protected] > > > -----Original Message----- > From: > sprinklerforum-bounces@**firesprinkler.org<[email protected]> > [mailto:sprinklerforum-**[email protected]<[email protected]>] > On Behalf Of Todd > Williams > Sent: Wednesday, August 24, 2011 5:21 AM > To: sprinklerforum@firesprinkler.**org <[email protected]> > Subject: Minimum pressures in water supply > > I am working on a new school project, where the building is 65 ft above > the water supply in the road and 760 ft horizontally. The water supply > is 54-46-1130. There is a pump planned, which I have to size. The total > pressure loss in the underground between the supply and the pump house > is approximately 30 psi. I know the general consensus (and some water > company requirements) is that the water pressure not be drawn down below > 20 psi. A 500 gpm at 60 psi pump would be a good fit for this project, > but the suction pressures at the pump would end up being below 20 psi. > The supply in the public mains would remain above 20 (due to the > elevation), but would be below that in the private main at the pump > room. Any thought if this would be acceptable? > > Todd G. Williams, PE > Fire Protection Design/Consulting > Stonington, CT > 860.535.2080 > www.fpdc.com > > ______________________________**_________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.**org <[email protected]> > http://fireball.firesprinkler.**org/mailman/listinfo/**sprinklerforum<http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum> > > > ______________________________**_________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.**org <[email protected]> > http://fireball.firesprinkler.**org/mailman/listinfo/**sprinklerforum<http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: <http://fireball.**firesprinkler.org/mailman/** > private/sprinklerforum/**attachments/20110824/0eebc788/**attachment.html<http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20110824/0eebc788/attachment.html> > > > ______________________________**_________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.**org <[email protected]> > http://fireball.firesprinkler.**org/mailman/listinfo/**sprinklerforum<http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum> > > > ______________________________**_________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.**org <[email protected]> > http://fireball.firesprinkler.**org/mailman/listinfo/**sprinklerforum<http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum> > ______________________________**_________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.**org <[email protected]> > http://fireball.firesprinkler.**org/mailman/listinfo/**sprinklerforum<http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum> > ______________________________**_________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.**org <[email protected]> > http://fireball.firesprinkler.**org/mailman/listinfo/**sprinklerforum<http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum> > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20110824/938726a1/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
