Nothing has broken yet and maybe will not, but I think you don’t get the right spray pattern out of over pressurized sprinklers. I understand the pattern starts to become directional. Perhaps this and the impact it could have on control performance has been pointed out to the parties involved.
> On Jun 27, 2018, at 3:39 PM, Prahl, Craig/GVL <[email protected]> wrote: > > It is a problem when the contractor is telling an owner that there is no > problem because their calculation shows the system only requiring 40 psi when > we know system pressures are going to actually be in the 200 psi range. > > The issue is with designers who are not properly instructed on what the > numbers mean in these calcs that they magically produce with a keystroke and > with an owner who believes every word they say as absolute. > > Craig Prahl | Jacobs | Group Lead – Fire Protection | 864.676.5252 | > [email protected] | www.jacobs.com <http://www.jacobs.com/> > > From: Sprinklerforum [mailto:[email protected]] > On Behalf Of Roland Huggins > Sent: Wednesday, June 27, 2018 2:42 PM > To: [email protected] > Subject: [EXTERNAL] Re: Real system pressures versus the calculations > > This is not an issue that is intended to be caught by the hydraulic > calculations for the system demand. It is purely and simply a deficiency in > the pump design (as already indicated by Matt). The original design was fine > but when someone changed the water supply, THEY were responsible for > ensuring the pump curve was still acceptable. > > This is also a problem for new systems when water supply modifiers are > applied. You have to size the pump for both the sprinkler demand based on > the lowest available supply pressure AND the churn limits based on the > highest supply pressure. > > Roland > > Roland Huggins, PE - Senior VP Engineering > American Fire Sprinkler Assn. > Dallas, TX > http://www.firesprinkler.org > <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.firesprinkler.org_&d=DwMFaQ&c=OgZOSER8c1RLeytEexU279Q2qk0jVwkrOdYe5iSi-kk&r=6qYbbLx8x0UrMujmEGNoh-2hzoFD2d1EB5d2sQF0_OI&m=9t3lHhKjiD1mJlP5Tp1xAPihIkIokW1byvR67Hld0rY&s=EMtRTfazpYo9Jqx2Sw8CRcqLKHDKE_c9kkImir7w8dU&e=> > > Fire Sprinklers Saves Lives > > > > > > On Jun 27, 2018, at 8:21 AM, Prahl, Craig/GVL <[email protected] > <mailto:[email protected]>> wrote: > > I have a system that was originally designed with a fire pump taking suction > from an elevated municipal water tank. At some point in time the system > source was changed from the tank to a municipal water supply. This change > has resulted in the system pressures being well over 200-250 psi. So far > nothing has blown out, yet but numerous buildings and underground were built > based on standard pressure rated components. > > The thought for the day is this, when you run a calculation, the output will > show the minimum required pressure at the hydraulically most remote sprinkler > that is required to provide the design flow rate. The calculations also show > the deviation between Required and Available system pressures. So, when the > fire pump kicks on, what the system ACTUALLY sees is the rated pressure of > the pump being introduced into the system, not the minimum required pressure > that is shown in the calculations, Agreed? > > If it is stated that in the calculations that the pressure at the sprinklers > on an upper floor will be less than 175 psi but those on the lower floor will > be greater is it safe to assume based on the ACTUAL pressures coming out of > the pump that the entire system will likely see pressures exceeding 175 psi? > > Looking for some thoughts. > > Craig Prahl | Jacobs | Group Lead – Fire Protection | 864.676.5252 | > [email protected] <mailto:[email protected]> | www.jacobs.com > <http://www.jacobs.com/> > > ________________________________________________________________________________________ > NOTICE - This communication may contain confidential and privileged > information that is for the sole use of the intended recipient. Any viewing, > copying or distribution of, or reliance on this message by unintended > recipients is strictly prohibited. If you have received this message in > error, please notify us immediately by replying to the message and deleting > it from your computer. > _______________________________________________ > Sprinklerforum mailing list > [email protected] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.firesprinkler.org_listinfo.cgi_sprinklerforum-2Dfiresprinkler.org&d=DwMFaQ&c=OgZOSER8c1RLeytEexU279Q2qk0jVwkrOdYe5iSi-kk&r=6qYbbLx8x0UrMujmEGNoh-2hzoFD2d1EB5d2sQF0_OI&m=9t3lHhKjiD1mJlP5Tp1xAPihIkIokW1byvR67Hld0rY&s=LFqsvqTbG0TxwJkem9z0zSbj8aK8rryLlMulraGnZlA&e=> > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
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