0.434 vs 0.433, U of M. Something to do with measurement of mass in the proximity of turtles. I don’t get it either. bv
> On 11/02/2023 6:00 AM PDT Bob Caputo <[email protected]> wrote: > > > > Lets look at this from the practical application side of things. The > standpipe and its valves are there for the fire service, solely and only. > Every department has its own operational standards, due in part to the hose > nozzles they choose. Some want the hose valves at intermediate landings, > some want them on the floor landing. Some want 100 psi, while others want > 125 psi at the hose valve (because there is about 29 psi appliance loss in > 100 ft of hose) and they want 100 psi at the nozzle. > > > > Here on earth, the pressure of elevation is the same for everyone: 0.433 psi > per ft of elevation – that is unless you went to the University of Maryland, > where its 0.434 psi per ft. 😉 > > > > Some departments want the FDC on the address side of the building, while > others may want more than one FDC for a high rise that is built on an entire > city block. Getting back to the point… NFPA 14 is a minimum standard for > the design and installation of standpipes which will be used by the first > responders – who should be the only one’s deciding the design criteria and > the location of equipment to be used in fighting fires. > > > > That’s my 2 cents – I hope that helps. > > > > bc > > > > > > Bob Caputo, CFPS > > President > > American Fire Sprinkler Association > > c: 760-908-7753 tel:760-908-7753 > > p: > > 214-349-5965 tel:214-349-5965 ext124 > > w: > > firesprinkler.org http://firesprinkler.org/ > https://www.facebook.com/firesprinkler.org/ > > https://twitter.com/afsa/status/1039528345367732224 > https://www.linkedin.com/company/american-fire-sprinkler-association-afsa-/ > https://www.instagram.com/firesprinklerorg/ > > > > Sprinkler Hydraulic Calculations Workshop > > > > AFSA’s three-day, in-person workshop provides a deep dive into the principles > of hydraulics, including the different types of pressure, calculating changes > in pressure (elevation and friction loss), and node analysis. Click here > https://www.firesprinkler.org/programs/calculations/ for details and to > register. > > > > > > From: Kyle.Montgomery <[email protected] > mailto:[email protected]> > Sent: Wednesday, November 1, 2023 6:21 PM > To: Discussion list on issues relating to automatic fire sprinklers > <[email protected] > mailto:[email protected]> > Subject: [Sprinklerforum] Re: [EXTERNAL] Re: Pressure Regulating Valves > Residual Pressures > > > > Well, they can’t have a minimum of 100 psi AND a maximum of 100 psi available > at the hose valve. So, if they want to limit the residual pressure to a > maximum of 100 psi, then they need to deviate from NFPA 14 and allow LESS > THAN 100 psi as the minimum. > > > > [Note: I suppose that maybe you could utilize a pilot-operated > pressure-regulating valve at every hose valve location to keep the pressure > right at 100 psi over a wide range of flow, but that would be unorthodox to > say the least.] > > > > Kyle Montgomery > > > > Aero Automatic Sprinkler Co. > > 21605 N. Central Ave. > > Phoenix, AZ 85024 > > Direct: 623.580.7820 tel:623.580.7820 > > Cell: 602.763.4736 tel:602.763.4736 > > [email protected] mailto:[email protected] > > > > > > > > From: Greg McGahan <[email protected] > mailto:[email protected]> > Sent: Tuesday, October 31, 2023 9:16 AM > To: Discussion list on issues relating to automatic fire sprinklers > <[email protected] > mailto:[email protected]> > Subject: [EXTERNAL] [Sprinklerforum] Re: Pressure Regulating Valves Residual > Pressures > > > > With all due respect Rick, I have had Fire Departments very concerned about > the residual pressure being greater than 100 psi for safety. Sizing PRV's is > not the easiest part of a standpipe design. If you are in a jurisdiction that > requires > > > > With all due respect Rick, I have had Fire Departments very concerned about > the residual pressure being greater than 100 psi for safety. > > > > Sizing PRV's is not the easiest part of a standpipe design. If you are in a > jurisdiction that requires flow testing and recording the pressures prior to > the final inspection (as it should be per NFPA 14), guessing could cost a lot > of money to correct. > > > > On Tue, Oct 31, 2023 at 10:49 AM Rick Matsuda <[email protected] > mailto:[email protected]> wrote: > > > > > The requirements of NFPA-14 for the standpipe hose valves are maximum > > 175-psi static outlet pressure and minimum 100-psi residual outlet pressure > > while flowing 250-gpm through the hose valve. > > If your pump source is from the city mains, then make it easy on yourself > > and select a PRV hose valve that will provide maximum 165-psi static outlet > > pressure. > > This should allow you to use whatever residual inlet pressure while flowing > > the 750-gpm total standpipe demand and still provide the minimum 100-psi > > residual outlet pressure. > > > > I used the 165-psi static outlet pressure cause the pump inlet pressure may > > vary up/down which will vary the pump static outlet pressure which may > > raise the static outlet pressure over 175-psi. > > > > If the pump source has a constant pressure like an elevated tank, then > > select a PRV that will provide a maximum 175-psi outlet pressure. > > > > Just my opinion but if you select a PRV based on the maximum static outlet > > pressure then this should allow a bit more than the 100-psi minimum outlet > > pressure. Check the charts to verify this. > > Don’t select a PRV based on providing just the minimum outlet pressure. > > I think that the fire department will appreciate any extra pressure to > > offset the friction loss through their fire hoses. > > Rick Matsuda > > > > > > > > > > > > On Oct 31, 2023, at 7:24 AM, Eric Rieve <[email protected] > > > mailto:[email protected]> wrote: > > > > > > > > > > > > > > > > > Micah, > > > > > > > > > > > > Looking at the spec sheet from Zurn I agree with Travis that you use your > > > expected residual pressure while flowing the full system demand of > > > 750gpm. I haven’t installed this valve myself, but you’ll notice on the > > > residual pressure charts that the bonnet type curve lines stop well below > > > 175psi. So, while you may pick a 120psi outlet pressure while flowing > > > 750gpm, the extra play in the curve should allow the valve to maintain an > > > outlet pressure below 175psi when being tested individually at 250gpm. > > > > > > > > > > > > Hope this helps! > > > > > > Eric Rieve, SET > > > > > > Rieve Fire Protection > > > > > > > > > > > > From: Micah Davis <[email protected] mailto:[email protected]> > > > Sent: Tuesday, October 31, 2023 6:53 AM > > > To: SprinklerForum <[email protected] > > > mailto:[email protected]> > > > Subject: [Sprinklerforum] Pressure Regulating Valves Residual Pressures > > > > > > > > > > > > Good morning, Forum! I hope everyone is having a great week!! > > > > > > > > > > > > I think I got this right, but someone is questioning me. I have an > > > automatic standpipe with factory pressure-regulating valves (i.e., Zurn > > > 4000). When calculating residual pressures at the inlet of the PRV to be > > > used in the sizing charts, the question is, how much water should I be > > > flowing in the system? One suggestion is only flowing 250 gpm at the > > > hose valve you are sizing. The other suggestion is flowing the system > > > demand flow per NFPA 14. In this case, that would be 750 gpm (250 gpm at > > > each of the two most remote hose valves plus 250 gpm at the top of the > > > only other standpipe). We are in agreement that the calculation should > > > be a source calc to determine the actual pressure provided by the system. > > > > > > > > > > > > Thank you, > > > > > > Micah Davis > > > > > > Ferguson Fire Design > > > > > > > > > _________________________________________________________ > > > SprinklerForum mailing list: > > > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > > > > > > https://urldefense.com/v3/__https:/lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org__;!!Ba8_KKAT!Kd8DM2LZyWcEocYD3fg3JDRWY4EbJccNoJAO5nUwJLrU7pZ1PertiR4yFJWGSKkoUpznUXzAlJwSH_Xv107ezuPG$ > > > To unsubscribe send an email to > > > [email protected] > > > mailto:[email protected] > > > > > > > > > _________________________________________________________ > > SprinklerForum mailing list: > > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > > https://urldefense.com/v3/__https:/lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org__;!!Ba8_KKAT!Kd8DM2LZyWcEocYD3fg3JDRWY4EbJccNoJAO5nUwJLrU7pZ1PertiR4yFJWGSKkoUpznUXzAlJwSH_Xv107ezuPG$ > > To unsubscribe send an email to > > [email protected] > > mailto:[email protected] > > > > > > > > -- > > Greg McGahan > > Genesis Fire Services, LLC > > 4912 Glover Lane. Milton, FL 32570 > > P- 850-637-8535 tel:850-637-8535 > > C- 850-712-9555 tel:850-712-9555 > > > _________________________________________________________ > SprinklerForum mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to [email protected] >
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