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)
