Bobby is correct. I have talked to NFPA on this matter and had an informal interpretation done.
Steven P. Biship, P.E. Pacific Fire Engineering www.pacificfireeng.com > The only reason I say a pipe feeding a single sprinkler can be a branch > line > is per definition. > > 3.5.1 BRANCH LINES The pipes supplying sprinklers........ > 3.5.2 CROSS MAINS The pipes supplying the branch lines either directly or > through risers. > 3.5.9 ARM-OVER A horizontal pipe that extends from a branch line to a > single > sprinkler or a sprinkler above and below a ceiling. > > So if you have a single sprinkler fed from a horizontal pipe from a cross > main this would be a branch line. If you have a single sprinkler fed from > a > horizontal pipe from a branch line this would be an arm-over. > > > Bobby Gillett > Project Manager > [EMAIL PROTECTED] > (731)-424-0130 > > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Roland > Huggins > Sent: Thursday, June 19, 2008 9:58 AM > To: [email protected] > Subject: Re: Restraint of Branch Lines > > I disagree that the definition states a single sprinkler is a branch > line. It says supplying sprinklers (plural) and that pipe can have > individual sprinklers off of it feeding arm-overs, sprigs etc. Just > like risers are all vertical pipes (for 4 way braces) but a sprig is > excluded since it is separately defined this nit a riser. The > individual sprinklers off of a branch line are separately defined and > addressed (sprigs greater than 4 ft, arm-overs greater than 2 ft, etc). > > An arm-over is not separately restrained. IT makes it easy to > adamantly say that when one considers long sections of pipes (attached > on only one side) easy whip around whereas short sections do not (the > length of the moment arm) > > Roland > > On Jun 19, 2008, at 5:56 AM, [EMAIL PROTECTED] wrote: > >> A branch line can be a single head per the definition in NFPA 13. >> Does >> this mean each arm-over, drop, or return bend regardless of length >> must >> have a branch line restraint? It seems sprigs are given special >> attention in Chapter 9 but the other categories of branch line are >> not. >> >> I guess I'm getting back to the confusion over the definition of a >> branch line. From the feedback it seems no one is providing restraint >> when a single head is involved. >> >> Bill Brooks >> >> William N. Brooks, P.E. >> Brooks Fire Protection Engineering Inc. >> 372 Wilett Drive >> Severna Park, MD 21146 >> 410-544-3620 Phone >> 410-544-3032 FAX >> 412-400-6528 Cell >> >> -------- Original Message -------- >> Subject: RE: Restraint of Branch Lines >> From: "Thom McMahon" <[EMAIL PROTECTED]> >> Date: Wed, June 18, 2008 4:50 pm >> To: <[email protected]> >> >> 13 defines restraint as a lesser level of control than Brace. We have >> always favored the 12Ga. 440 Lb. Ceiling wire restraint on the end of >> branchlines (9.3.6.1 end Head) If it doesn't have heads on it, it is a >> feed or cross main and requires bracing. (See branchlines over 2") >> (This >> includes all head types, SSU, SSP and HSW even flex heads if the last >> head on the line is a flex head) >> The new 2007 hanger with 2nd hanger at 45' angle may appeal to some. >> In >> any case when you're doing seismic the end of branchlines must be >> restrained.(I always try to keep my hangers less than 6" and it's a >> lot >> easier.) >> >> The more difficult restraint requirement A9.3.6.4 is when your close >> to >> other objects that can damage the branchline in a seismic event. >> Components of the structure, duct work or large mechanical piping. >> Also >> your always required to use restraint per 9.3.6.4 (see table) on >> longer >> branchlines. Again a little clarification that this is not cumulative, >> it is based upon the smallest pipe size in the branchline.(13 HB >> committee, yes or No?) (Part of this answer depends upon weather the >> other trades are providing seismic bracing, and a good feel for how >> close is too close, NOT YET DEFINED BY 13) >> >> Example:( A branchline which follows pipe schedule sizes with every >> head >> 12' from the last with a 21/2" starter piece, and 10 heads total. >> (112'-0" total length) you have your end restraint, the with a Cp 0.58 >> you space your next restraint 38' from the end one. Then since your >> now >> on a 11/2" piece of the branch line do you space 38' again or 43'? The >> end answer is it doesn't really matter, you need the end on plus two >> more either way, but I see both sides of that, and it's not real >> clear.) >> >> Thom McMahon, SET >> Firetech, Inc. >> 2560 Copper Ridge Dr >> P.O. Box 882136 >> Steamboat Springs, CO 80488 >> Tel: 970-879-7952 >> Fax: 970-879-7926 >> >> >> >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of >> [EMAIL PROTECTED] >> Sent: Wednesday, June 18, 2008 12:54 PM >> To: [email protected] >> Subject: Restraint of Branch Lines >> >> 2007, 9.3.6.3 - The end sprinkler on a line shall be restrained >> against >> excessive vertical and lateral movement. >> >> 1. Can I assume the word line means "branch line" based on the title >> of >> 9.3.6? >> 2. Would the end sprinkler include sprinklers on drops, arm-overs, and >> return bends? >> 3. Would "excessive" be defined as using a restraint not listed for >> vertical and/or lateral movement or not meeting 9.3.6.1(5)? >> >> Someone has asked me to approve a particular brace but then I >> realized I >> had no idea how many needed to be installed! >> >> (Getting old but still learning) >> >> Bill Brooks >> >> William N. Brooks, P.E. >> Brooks Fire Protection Engineering Inc. >> 372 Wilett Drive >> Severna Park, MD 21146 >> 410-544-3620 Phone >> 410-544-3032 FAX >> 412-400-6528 Cell >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> To Unsubscribe, send an email >> to:[EMAIL PROTECTED] >> (Put the word unsubscribe in the subject field) >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> To Unsubscribe, send an email >> to:[EMAIL PROTECTED] >> (Put the word unsubscribe in the subject field) >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> To Unsubscribe, send an email >> to:[EMAIL PROTECTED] >> (Put the word unsubscribe in the subject field) >> > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:[EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:[EMAIL PROTECTED] > (Put the word unsubscribe in the subject field) > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
