AS the specifying engineer, there is another approach since you are not laying-out and calculating the system and yet you’re required to size the tank (THUS MY REASON FOR TRYING TO CHANGE IT). Use the curves along with a modifier then spec that the system shall be designed with a maximum overage of X amount such that the system demand does not exceed the amount reflected by the modifier you used in your tank calculation.
Ba-Da-BOOM, Roland Roland Huggins, PE - Senior VP Engineering American Fire Sprinkler Assn. Dallas, TX http://www.firesprinkler.org <http://www.firesprinkler.org/> Fire Sprinklers Saves Lives > On Mar 25, 2019, at 1:54 PM, Prahl, Craig/GVL <[email protected]> wrote: > > Well Okie Dokie then. 99% of the time I am just estimating tank capacity > since we’re not providing final calcs. But that estimate typically is on the > conservative side of what the final calcs usually end up requiring. Plus > when having to provide for Fire Flow, the tank sizes will always exceed what > the sprinkler demand requires. > > Craig Prahl | Jacobs | Group Lead – Fire Protection | 864.676.5252 | > [email protected] <mailto:[email protected]> | www.jacobs.com > <http://www.jacobs.com/> > > From: Sprinklerforum <[email protected]> On > Behalf Of Roland Huggins > Sent: Monday, March 25, 2019 4:40 PM > To: [email protected] > Subject: Re: [EXTERNAL] Re: Water Tank > > But they HAVE said that. > Start with 11.1.4.1 - the water demand shall be determined (occupancy hazard > approach etc) > Staying with the occupancy hazard approach (to minimize the number of > referenced section), section 11.2.1 - The water demand requirements shall be > determined by either pipe schedule or hydraulic calculation method. > Section 11.1.5.2 tanks shall be sized to supply the equipment they serve. > > Since the tank is the water supply that must meet the system demand, then > there you go in black and white. > > 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=_w721WvezJkWUVteY4FMhecHAoDqOn85ooHi6vIkMag&m=A1aSZLxw_0z8oJjzXuv2Hyny-XXah9O6aXha2-X5gC8&s=q8QWKnv9OL33pzKnOtvcWM9AY528GeHcwnbubo4N5yc&e=> > > Fire Sprinklers Saves Lives > > > > > > On Mar 25, 2019, at 12:17 PM, Prahl, Craig/GVL <[email protected] > <mailto:[email protected]>> wrote: > > Well I look at it this way. If you used the curves and factored the value up > by an additional 15 – 20% you should be fine considering the mantra is that > most fires are controlled by only 1-3 sprinklers not the entire calculated > hydraulically remote area. But, if the committee believes it should be done > a certain way then put it in black and white and eliminate any confusion and > guessing. > > Craig Prahl | Jacobs | Group Lead – Fire Protection | 864.676.5252 | > [email protected] <mailto:[email protected]> | www.jacobs.com > <http://www.jacobs.com/> > > From: Sprinklerforum <[email protected] > <mailto:[email protected]>> On Behalf Of Roland > Huggins > Sent: Monday, March 25, 2019 2:03 PM > To: [email protected] > <mailto:[email protected]> > Subject: [EXTERNAL] Re: Water Tank > > The NFPA 13 committee believes the tank size is indeed based on the > CALCULATED volume of water. I know this because I attempted several cycles > ago to state we should simply use the curves with a modifier. I was almost > burned at the stake for uttering such blasphemy. > > 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=DwMFAg&c=OgZOSER8c1RLeytEexU279Q2qk0jVwkrOdYe5iSi-kk&r=_w721WvezJkWUVteY4FMhecHAoDqOn85ooHi6vIkMag&m=LSitVO9kRtffCU2_Kq1AFwMHMwU4R9POZX1mHsm-XJo&s=ECrKtTShUpl6Us21CbW8dwSOVQYGFhIkaRkmw0MtKKQ&e=> > > Fire Sprinklers Saves Lives > > > > > > > On Mar 20, 2019, at 7:48 AM, AKS-Gmail-IMAP <[email protected] > <mailto:[email protected]>> wrote: > > Tank sizing for some situations presents an uncomfortable dilemma because > there are pressures from all sides to minimize the tank size yet we all know > the tank contains the single most important item. Some codes can be argued to > say the size is for sprinkler demand only. The code might also qualify that > by implying the actual system calculated sprinkler demand is used for sizing. > So in this case the OH-2 system might have a 1.8 overage at its most > demanding location. But then what happens if the fire event occurs at the > least pressure demanding part of the system where the overage is higher than > 1.8? Here we can only hope that more water in less time is better and perhaps > not so many sprinklers open and someone is present to manage the run time. > The same pressures to limit the tank size might also work against installing > a more water efficient sprinkler system for that OH-2 space. > > > > > 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=_w721WvezJkWUVteY4FMhecHAoDqOn85ooHi6vIkMag&m=A1aSZLxw_0z8oJjzXuv2Hyny-XXah9O6aXha2-X5gC8&s=OLCFJ3xUHR0YhoVVOrd-TUIB0BvLuLyt3dE_zGwuzi4&e=> > > > > 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. 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