Computer Programs -- DATA -- garbage in = garbage output Locally Most information is Good with the computer models having a 10% or 10 psi safety factor.
I have received Information that has been has been BOTH high psi Static and LOW psi static & GPM at 20 psi that goes off the HASS HRSS chart (over 9999 gpm) I have helped Local AHJ and Water Dist. to confirm DATA and asked to put Gauge on Hydrant to check static psi. flushed a Local private hydrants and Collected Data to compare to Water Info flushed UNDERGROUND and Collect DATA A few local Water Districts oversee Hydrant Flow Tests (Are they being flushed every 5 years?) and a Few jobsites may have 88 psi Static .... but 10% off another 5% for worst case in 25 years and they give us 72 psi static well with a few 74' building with Attic Dry or a 50 year old Warehouse with storage I NEED ACTUAL STATIC PSI FOR possible fire pump design NOT flow test from a computer model that says 66 psi and flowing 3000 gpm at 50 psi and limits water to 10 fps (how many hydants are flowing?) (Does City of R....& L.... Fire think about velocity ? when we do actual of standpipe flow tests NO ) around 200 psi @ Pumper Truck +- 175 psi at FDC 165 @ Riser flowing 1100 - 750 gpm with 100 psi residual at High Point RECOMMENDATIONS when Water Districts flush hydrants Collect Data for Computer Models. Chuck Bamford S.E.T. On Wed, Aug 31, 2022 at 11:22 AM Fpdcdesign <[email protected]> wrote: > I think a lot of this depends on the sophistication of the software and > hardware used, which could also be a function of the size of the water > company. In the Northeast, we have a lot of small water companies that only > service a specific town or section of town. Near the larger cities, you get > regional authorities that cover several towns but there may or not be any > interconnections. Also, several municipal water companies have been bought > up by holding companies but they still operate as independent units. They > don’t have the resources to spend on a sophisticated modeling system. > > One of the companies that services the town I live in tried a modeling > system. It consisted of little more than a 3D computer model of the system > connected to a pump. Something I could do with Autosprink. I believe they > had a run of unlined cast iron pipe from 1888 listed as C=120 (or the D-W > equivalent). Needless to say the accuracy is a joke. I think it has been > abandoned. > > Todd G Williams, PE > Fire Protection Design/Consulting > Stonington, CT > 860-535-2080 (ofc) > 860-554-7054 (fax) > 860-608-4559 (cell) > > > On Aug 31, 2022 at 1:15 PM, <Steve Leyton <[email protected]>> > wrote: > > T-Mack’s comments reminded me of one other distinct advantage to models – > I can get two or more per project relatively easily if I need to. Our > firm designs a lot of private hydrant systems in addition to building > sprinkler systems, so the benchmark we need for highest accuracy might be > 3,000 GPM flow or 350 gpm flow. As others have noted, the higher the flow > rate the more accurate the data (vs. extrapolation), and with most > agencies, I can request models at whatever fire flow rate I choose. > > > > Steve > > > > *From:* [email protected] <[email protected]> > *Sent:* Wednesday, August 31, 2022 9:46 AM > *To:* [email protected] > *Subject:* [Sprinklerforum] Re: [EXTERNAL] Hydrant flow tests > > > > Maybe because I am in the SW with Steve, I agree 100% with his statements > here. We can get situations modeled for basically anything we want > regarding the water supply. As Steve mentioned, many water agencies have > decades of data to accurately model this stuff. I have to ask why we will > rely on hydraulic calculation models for our fire sprinkler systems, if we > won’t rely on similar calculation models for the water supply? The math > doesn’t change just because it is a sprinkler vs a hydrant. > > > > Our experience has been more positive with models than with actual flow > testing. We’ve had customers go “flow test shopping” where I found out > later that they did multiple flow tests and gave us the best one that they > obtained. Well, that’s great if you can guarantee a fire will only occur > during that time frame. The computer models will account for peak demand, > anticipated changes, and other things that a simple flow test can not > account for. > > While I am old school and do like to have it confirmed by an actual flow > test if possible, I tend to feel the models are more reliable and accurate > over longer periods. Now, all of this is to say that it is based on the > model database of information to be accurate. If there are errors in the > database or user entering the information for the model it fails. That is > no different than someone using an un-calibrated gauge, not applying pumper > coefficients or getting incorrect hydrant coefficients, let alone not > choosing the worst-case time of day for a flow test. > > > > *Please rate our customer service > <https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fsurvey.medallia.com%2f%3femailsignature%26fc%3d3539%26bg%3dFire%2520and%2520Fabrication&c=E,1,wv1KVigAKuTRqcaSNc4pOZWCeagx-cP1kMlCKE8h7pS48OQSn6sq5itvRRdcmq8opQ2Q6Jx5GIdlWoWFi--9DawdWzMxzMf3H9pfJ-7GSaKFDeY,&typo=1>* > > > > *Travis Mack, RME-G, COC, SET* > > *Senior Engineering Manager* > > *MFP Design* > > 480-505-9271 ext. 700 C: 480-272-2471 > > [email protected] > > [email protected] > > www.mfpdesign.com > <https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.mfpdesign.com&c=E,1,i9qf3bbsyv8viIjgOz35g6OUEOU8y_Fb35HidPh5Fy5fUjakm34El4fK3J0RuCX-nr30TdcTmyQhK0NBpYGnIn02l4eaRI9g28fnhDYTPSDjBA,,&typo=1> > > > > Send large files to us via: https://www.hightail.com/u/MFPDesign > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.hightail.com%2Fu%2FMFPDesign&data=02%7C01%7C%7C1121d49f9e6b4cf248f108d4df580e77%7C14e5497c16da42e69ffa77d19bafe511%7C0%7C0%7C636379016677342180&sdata=eGdMZGu2wXhUupGwgGTrqF3b54OP5%2BAZvlHhABSexWY%3D&reserved=0> > > > > *From:* Steve Leyton <[email protected]> > *Sent:* Wednesday, August 31, 2022 9:35 AM > *To:* Discussion list on issues relating to automatic fire sprinklers < > [email protected]> > *Subject:* [Sprinklerforum] Re: [EXTERNAL] Hydrant flow tests > > > > I respectfully, but stridently disagree. To this comment and Rick’s > overarching question, I would offer that our experience over the past 10+ > years has been that these models are not only accurate, they are highly so > and can be programmed for eventualities and conditions that flow tests > simply cannot reflect, because they are a measurement of the “right now” > only. But I would offer an bold asterisk on my comments because they are > based on regionality and I’m in the SWUSA, where water management has been > a critical thing for a full generation now. > > > > Because of drought concerns going back 20+ years, many water agencies > stopped doing flow tests and began to meter their systems. Today, nearly > all water agencies in California will only grant a permit to do a physical > flow test if there are compelling circumstances, and we rely on models. > Using San Diego County as an example, water districts began installing > sensors 25 years ago and have been collect metadata on overall system > performance for dozens of years; these systems are in fact predictable if > the database used to calculate performance is well-populated and highly > detailed. I was going to offer Rick the anecdote of how we designed a > whole campus high school 15 years ago, in a subdivision that was brand > new. The only “flow data” we had to work with was the master developer’s > civil engineering water study, which was based on the zone model from the > water district. And it said that the static was going to be so high (182) > that we needed to install pressure reducing valves on the supply side of > the backflows feeding the site loop. We also used the model for sprinkler > hydraulics, but corrected the pressures downward for the PRV settings. > When the permanent system was commissioned into service (two years later > and with sprinkler systems 80-90% installed) the static pressure was 181 > and the residual was exactly the same as modeled. > > > > Programmability of models enables simulation of worst-case scenarios, > particularly peak day demand, annual drought predictions and legacy drought > conditions. This is extremely important in the West as our water levels > are literally dropping every year, so maybe that’s why our water agencies > have established such high standards of care for modeling. City of San > Diego doesn’t require that you take 10% off of their models any longer – > why? Because they program peak day demand, legacy drought levels and an > additional safety factor. When they first started this practice, the FP > community was going nuts – field conditions showed 10-20 PSI more pressure > at the hydrants in some cases. Yes, pipe sizing was affected, but if > we’re talking about safety and prudence (without consideration for the > cost-impact, obviously), this methodology yields solidly conservative data > for basis of design. > > > > Chains are only as strong as their weakest link and physical flow testing > only reflects current conditions. Was the test done during a peak day > demand window? Was the test measured with a $10-15 spring loaded gauge (up > to 8-10% error) or a calibrated liquid-filled one with a 1% error or > less? Was the test even taken by skilled personnel? My opinion on this > has swung – I’m now pro-model and we look at physical testing as an archaic > practice, and I’m a shamelessly analogue Boomer. > > > > > > Yours in the name of fire safety and progress, > > Steve L. > > > > > > > > *From:* Prahl, Craig <[email protected]> > *Sent:* Wednesday, August 31, 2022 8:10 AM > *To:* Discussion list on issues relating to automatic fire sprinklers < > [email protected]> > *Subject:* [Sprinklerforum] Re: [EXTERNAL] Hydrant flow tests > > > > Having experienced bogus results from computer modeling on more than one > occasion, nothing matches the actual flow of the hydrant systems. > > > > Most recently I got a water report from a local municipality who generated > the info via their water modeling software. It said I could expect 6700 > gpm from the system……. via 8” lines at 10 fps! Nope, don’t think that’s > going to be a real thing. > > > > Craig Prahl | Jacobs | Group Lead/SME – Fire Protection | > [email protected] | www.jacobs.com > > 1041 East Butler Road Greenville, South Carolina 29606 > > CONTACT BY: Phone 1-864-676-5252, Email or MS TEAMS > > > > > > > > *From:* Rick Matsuda <[email protected]> > *Sent:* Wednesday, August 31, 2022 9:51 AM > *To:* [email protected] > *Subject:* [EXTERNAL] [Sprinklerforum] Hydrant flow tests > > > > I know that an accurate flow test is critical for the sprinkler system > design, but I’ve heard several discussions recently about water > conservation during our drought conditions across the SW states. > > > > With all our technology, is it possible to develop an accurate computer > modeling program for water departments to use in lieu of flow tests? Even > with the program, I think there would still be a need for some flow tests > to verify the program results, but maybe not as many as now. > > > > I’m not taking any pro/con position regarding this issue. I’m just > providing food for thought for the future as our need for water increases > and our resources diminish. Adequate water is the key for our industry. > > > > It’s ironic cause we get more wild fires due to the drought, and then we > have to use more water to fight the fires. > > Rick Matsuda > > > > > ------------------------------ > > > 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: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to > [email protected] > > > _________________________________________________________ > SprinklerForum mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to > [email protected]
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