Whether each floor is supplied through a floor control valve, or piped vertically from a common horizontal main on the 1st floor, I believe that the compelling factor is in the typical spaces, pipe sizing, routing, etc.
Another scenario would be where the floors are zoned separately (from a standpipe) and are not typical; however, a proven limitation on how many sprinklers can be supplied through a given size of branch line is calculated. Hope this doesn't muddy up the conversation too much. Curtis -----Original Message----- From: Steve Leyton [mailto:[email protected]] Sent: Tuesday, August 05, 2014 12:29 PM To: [email protected] Subject: RE: Calculating Typical Floors "... obvious by comparison ..." That's pretty simple for an experienced technician or plans reviewer, but perhaps not so simple to someone with less experience or who's intent on the most literal and trying interpretation and enforcement of the standard. Again, what information is gained by calculating typical floors that are of similar (or typical) layout and sizing, except for the static head gain or loss between floors? The annex material notwithstanding, what's the point? I'd ask that question in writing ... SL -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Duane Johnson Sent: Tuesday, August 05, 2014 10:22 AM To: [email protected] Subject: RE: Calculating Typical Floors You can try (although I wouldn't) using this paragraph too. I have typically used this to request additional calcs, but you can try it for your situation...by comparison, it should be obvious that you selected the hydraulically most demanding and therefore you do not need additional calcs. Good luck. A.23.4.4.6 When it is not obvious by comparison that the design selected is the hydraulically most remote, additional calculations should be submitted. The most distant area is not necessarily the hydraulically most remote. Duane Johnson, PE Design Manager Strickland Fire Protection 5113 Berwyn Road College Park, Md. 20740 301-474-1136 Office 301-455-0010 Cell [email protected] -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Duane Johnson Sent: Tuesday, August 05, 2014 1:16 PM To: [email protected] Subject: RE: Calculating Typical Floors I agree with you on the hydraulically most demanding area needs to be calculated. One should be able to use reason that if the floors are the same, and the highest floor works hydraulically, the others will have a larger safety factor because there is less friction loss due to elevation. Likewise in a warehouse with multiple risers, one typically does not provide calcs for each riser/zone. As far as your defined system goes... A.3.3.22 Sprinkler System. As applied to the definition of a sprinkler system, each system riser serving a portion of a single floor of a facility or where individual floor control valves are used in a multistory building should be considered a separate sprinkler system. Multiple sprinkler systems can be supplied by a common supply main. Duane Johnson, PE Design Manager Strickland Fire Protection 5113 Berwyn Road College Park, Md. 20740 301-474-1136 Office 301-455-0010 Cell [email protected] -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Tuesday, August 05, 2014 12:42 PM To: [email protected] Subject: RE: Calculating Typical Floors NFPA 13 states in 23.4.4.1, "For all systems the design area shall be the hydraulically most demanding based on the criteria of Chapter 11, Chapter 12, or the special design approaches in accordance with the requirements of Chapter 22." So unless each floor is defined as a "system" (which we know not to be the case), then the standard only requires that you pick THE most demanding area for each system. Sometimes, we do multiple calculations but it's generally because we don't want to size all the Light Hazard rooms for the few OH or limited storage that may occur as accessory use elsewhere under the same system. So picking the uppermost of a series of typical floors is consistent with that intent, so long as the lower floors are sized per the uppermost one. What is the plans reviewer's substantiation for the requirement, i.e. what do they think they're going to find out beyond the static head gain by going down a floor at a time? Are designers in this jurisdiction taking the pressure gain and re-sizing pipe as they drop floor by floor in buildings such as this? SL -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Curtis Tower Sent: Tuesday, August 05, 2014 8:14 AM To: [email protected] Subject: Calculating Typical Floors We have had several projects rejected by the plans examiner recently because we didn't hydraulically calculate each floor. These are multi-story residential projects with typical floor plans. Some of the projects are zoned per floor, but others are piped with the main on the first floor and supplied with the CPVC branch lines running vertically through the walls. This is possible, as mentioned, due to the identical nature of the unit layout of each floor. The Section Manager of the sprinkler review department evidently interprets the standard to require hydraulic calculations for every floor, regardless of typicality. Does anyone see this as a correct interpretation or necessary? I've asked him to provide the section of the standard that he is relying on to justify this. It seems somewhat burdensome, considering all things remaining the same except a drop in elevation, one could reasonably expect an increase in available pressure to the system on the floor below. Curtis Tower Sr. Fire Protection Specialist Central Fire Protection Office: (214) 496-9797 Mobile: (682) 667-0323 Fax: (214) 496-9201 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler .org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler .org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler .org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler .org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
