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]<mailto:[email protected]> [email protected]<mailto:[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]<mailto:[email protected]>> Sent: Wednesday, August 31, 2022 9:35 AM To: Discussion list on issues relating to automatic fire sprinklers <[email protected]<mailto:[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]<mailto:[email protected]>> Sent: Wednesday, August 31, 2022 8:10 AM To: Discussion list on issues relating to automatic fire sprinklers <[email protected]<mailto:[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]<mailto:[email protected]> | www.jacobs.com<http://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]<mailto:[email protected]>> Sent: Wednesday, August 31, 2022 9:51 AM To: [email protected]<mailto:[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.
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