If a pump is capable of serving both the domestic and fire demands, and feeds both concurrently and without interruption to the domestic, I believe it fulfills the intent of 9.3 (4). IMHO, combined water supplies utilizing a pump that feed both domestic and fire are desirable because of regular exercise to the pump and an obvious means of detecting trouble as the domestic system will be encumbered on non-op. The intent of 9.4 is to identify a pump that serves fire only (FIRE pump) and thus, trigger the requirement for listing and conformance to 20. I don't necessarily agree with Chris's statement regarding an engineered solution - we attach a huge stigma to anything plumbing-related, yet plumbing systems seem to work pretty well for the most part and I'm still waiting to read about a wave of failures in domestic plumbing systems that feature pumps.
To George's point, it's obvious that in some cases it won't be prudent or practical to combine the water supplies on a single pump, but I've done a sketch for a single family combined water supply that features two pumps. We originally used this configuration in a home on Maui that took drinking and fire water from a rain water cistern, and which flows down to the house with only about 10 PSI PSH. The pumps are rated 40gpm @45psi and 15gpm @ 25psi, if I recall correctly. The intent is to draw water from the cistern through the 40gpm and pump directly to the sprinkler system. Branching off of that is the domestic feed, which packs a pressure tank, downstream of which is the 15gpm pump. The pressure tank is sized so that it will require approximately 50 gallons of refill when the pressure drops to the switch setting, thus exercising the bigger pump for at least a minute, which the pump peeps tell me is the right duration. When there is a domestic demand, the domestic booster kicks on if a second pressure switch triggers it, otherwise the pressure tank supplies the flow directly. The intent is to exercise both pumps all the time and to know immediately if there's a problem with the water supply by way of the domestic system. A larger scale version of this would be possible for a 13R system, but still not necessarily practical. The foregoing is my opinion only and does not necessarily represent the opinion or intent of the NFPA 13D/13R Technical Committee on Residential Sprinkler Systems. Steve -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Church Sent: Friday, January 14, 2011 8:36 AM To: [email protected] Subject: RE: 2010 NFPA 13R 9.3 Great idea, but I don't think its going to work. The intent is for the fire pump and related supply to be, insofar as possible, dedicated to FP use. Fire pumps shouldn't be run daily for domestic boosting. You're turning on a 300 GPM pump (in a hotel) for domestic demand? Water hammer. Variable spped would be good- in a fire pump-$$$^^ Host of issues....in 13 ARGH. George Church' Rowe Sprinkler [email protected] 570-837-7647 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Andy Sent: Friday, January 14, 2011 11:33 AM To: [email protected] Subject: RE: 2010 NFPA 13R 9.3 Does that mean we can install Fire pump sized to handle the fire and the domestic load? They maintain the domestic pumps better than the fire pumps. Any body sell a fire pump approved for domestic? Andy -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bill Brooks Sent: Friday, January 14, 2011 9:30 AM To: [email protected] Subject: RE: 2010 NFPA 13R 9.3 1994 - The NFPA 20 pump was linked to a stored water source. A water works system was related to a booster pump. 1999 - NFPA 20 pump required in all cases. 2002 - Seems to track with 1999 except new paragraph 6.5.4 is added (with no indication it's new and no substantiation since it was part of a general manual of style reformatting). The intent of the new paragraph appears to mean that all pumps are to be fire pumps since there is no indication this paragraph was anything but a formatting change. 2007 - Same as 2002. 2010 - Same as 2002. I think the intent is NFPA 20 in all cases (except the well source) described by NFPA 13R since the 1999 edition. Bill Brooks William N. Brooks, P.E. Brooks Fire Protection Engineering Inc. 372 Wilett Drive Severna Park, MD 21146-1904 410-544-3620 410-544-3032 FAX 412-400-6528 Cell -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Church Sent: Thursday, January 13, 2011 5:45 PM To: [email protected] Subject: RE: 2010 NFPA 13R 9.3 If you can have a well with sufficient refresh and capacity, you can oversize the well pump and have a reliable water supply which fulfills either (1) or (4) depending on semantics/definitions. And what's APPROVED. We happened across a 36" diam well with 3,000 gal in it, oversized the well pump, connected it to the sprinklers and a new gang bath in this housing project, and saved the customer $25,000. My understanding is the same as Cliffs, but upon re-reading the original text, no-it does NOT say that a FIRE pump must be used, just that IF you install a fire pump, do it per #20. Betcha that wasn't the intent of the committee. George Church' Rowe Sprinkler [email protected] 570-837-7647 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Blackwell Sent: Thursday, January 13, 2011 4:58 PM To: [email protected] Subject: 2010 NFPA 13R 9.3 The code text in 2010 NFPA 13R 9.3 mentions only "pump", not "fire pump" as the minimum standard requirement. Is that correct? [I read the commentary to both 9.3 and 9.4 and began to doubt whether a non-fire pump could be used. It is clear that 9.4 code requires, where used, a fire pump must meet NFPA 20; however, I don't read 9.3 as actually requiring a fire pump be used to meet the "pump" indicated in 9.3(1) or 9.3(4).] Perhaps my brain will work better in the morning while still fresh... Respectfully, David W. S. Blackwell, II, PE, CFPE Engineering ---------------------------------------------------------------- Office of State Fire Marshal 141 Monticello Trail Columbia, SC 29203 Phone: 803.896.9833 Fax: 803.896.9806 Email: [email protected] OSFM Website: http://www.llr.state.sc.us/firemarshal.asp ---------------------------------------------------------------- _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
