Indeed, it does sound like a legit question. I guess the next question would be does the city have a minimum pressure requirement?
--- On Wed, 11/17/10, ParsleyConsulting <[email protected]> wrote: From: ParsleyConsulting <[email protected]> Subject: Re: Fire Pump's To: [email protected] Date: Wednesday, November 17, 2010, 10:45 PM Ralphy, >From the material that Brian sent over to me, he did indeed show the pump >flowing 150% of it's rated capacity back to the municipal supply. At that point on the supply curve the municipal supply could deliver the flow, but it would only be at a pressure of approximately 18.8 psi The supply curve was 86 psi static, 68 psi residual, at a flow of 920 gpm. The pump was rated at 1250 gpm at 75 psi. And I think you're right, based on the info I read in the '10 edition of NFPA-20, as well as the notes in NFPA-25 on annual testing, this calculation should be done. The FM who Brian was dealing with wasn't concerned about the sizing of the underground, or for that matter, the demand of the fire sprinkler system. His only concern was - apparently - what pressure is available from the supply when the flow is pushed to 150% of the rated capacity? Sounds to me like a legitimate question. PARSLEY CONSULTING Ken Wagoner, SET 760.745.6181 voice 760.745.0537 fax [email protected] <mailto:[email protected]>e-mail www.ParsleyConsulting.com <http://www.ParsleyConsulting.com>website On 11/17/2010 1:12 PM, Ralphy Henderson wrote: > I've done separate calcs in the past just showing the friction losses > occurring during 150% of rated flow. Shouldn't this be done anyways to verify > that the municipal water pressure isn't getting dangerously low? > > I'd just show the fire pump flowing the 150% with nothing else going on just > to verify A) The UG is sized appropriately and B) You're not sucking the > municipal water dry. > > > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
