Rocci, Main drain tests during system acceptance are performed simply to record the values for future comparison during NFPA-25 inspections and aren't a valid way of evaluating hydraulic demand.
If the water supply is sufficient for the new system design, then you should be able to rectify this by performing a backflow forward flow-test at the water supply stub-in, measuring your flow and residual pressure, and comparing that to the required flow and pressure at the corresponding hydraulic node on your calc sheet. This test is still not 100% valid since it doesn't account for pressure drop associated with outside hose allowance, so your results should show more safety factor than calculated at this point. I would also make sure that your 4th floor main drain test is consistent with main drain tests performed on the lower zones after accounting for elevation just to confirm there isn't something wrong right at the new floor control assembly. Hope this helps! Eric Rieve, SET Rieve Fire Protection From: Rocci 3 Cetani <[email protected]> Sent: Wednesday, September 11, 2024 10:18 AM To: [email protected] Subject: [Sprinklerforum] main drain test We have a jurisdiction that failed our final inspection because the residual pressure during the main drain test doesn't match our BOR residual pressure from the hydraulic calcs for and OH extended coverage system. Am I missing something? I don't see how the residual pressure on a main drain test has anything to do with the residual pressure from our calcs.....I was always under the impression main drain tests were to verify there hasn't been a been a drastic change to the supply . This was an existing parking garage where they added solar panels on the top level so we added a sectional riser @ the top floor and added the new system. The fire department just keeps saying to upsize the riser from the 1st floor to the 4th floor which literally does nothing to my calcs. The building owner has spent 10's of thousands of dollars flushing the UG, inspecting the UG for obstructions, paid for additional flow test and serviced the back flow. We are at a complete loss on what else to do as the fire department is adamant that's the main drain test has to match the hydraulic calcs.....anyone ever come across a situation like this with a jurisdiction? Any suggestions? Rocci Cetani III Northern California Fire Protection Services Inc. 16840 Joleen Way Bldg. A Morgan Hill, CA 95037 P-(408) 776-1580 EXT.1010 F-(408) 776-1590 To help better serve you. Please visit our new and improved website at: www.norcalfire.com<http://www.norcalfire.com/> CONFIDENTIALITY NOTICE: This message and any document accompanying it may contain confidential information belonging to the sender. The information is intended only for the use of individual or entity named above. If you are not the intended recipient, or the employee or agent responsible to deliver this message to the intended recipient, you are hereby notified that any disclosure, copying or taking of any action in reliance on the contents of this information is strictly prohibited. If you have received this transmission in error, please immediately notify us by telephone to arrange for return of the documents.
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