Tony: What Steve is trying to say in his normal straight to the point way, is that a 4" drain will normally handle the 250 to 300 GPM max flow you get from a 2" main drain test. That is if your water company isn't providing flows over 90 PSI residual. Anything over 320 gallons exceeds 32 ft per second velocity and it takes more pressure to exceed that.
John Paulsen - SET Crown Fire System Design 6282 Seeds Rd. Grove City, OH 43123 P - 614-782-2438 F - 614-782-2374 C - 614-348-8206 From: Sprinklerforum [mailto:[email protected]] On Behalf Of Tony Cetani Sent: Thursday, April 26, 2018 5:03 PM To: [email protected] Subject: RE: main drain flows They are looking for the GPM flows out of our main drain during a main drain tests. Since a lot of water is going to be released during the test they want to make sure the sanitary sewer can handle all the water with the main drain fully open under city pressure. Tony From: Sprinklerforum <[email protected]<mailto:[email protected]>> On Behalf Of Steve Leyton Sent: Thursday, April 26, 2018 1:53 PM To: [email protected]<mailto:[email protected]> Subject: RE: main drain flows Tell them you want a hub drain with a self-priming 4" trap. It'll resolve both 1ΒΌ" and 2" main drain discharges. Steve From: Sprinklerforum [mailto:[email protected]] On Behalf Of Tony Cetani Sent: Thursday, April 26, 2018 1:51 PM To: [email protected]<mailto:[email protected]> Subject: main drain flows Long time reader, first time writer.....actually not that long I'm a fairly new designer. We have a jurisdiction where they require the main drain to drain to a sanitary sewer and the contractor is asking what the flows will be so they can size their SS line accordingly. The sprinkler system hasn't been designed yet and they said they need to know right now so they can finish their design and submit for permit. Is there a way to figure this out (or get a ball park) just based off city water flow numbers? Thank you Tony
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