I have a situation where there are open web joists (wood t&b cord w/ open metal web). The system is a tree with 4" main and 1-1/2" branch lines. The problem is loading, the manufactures data allows only 240 lbs of force, and when I apply the loading from both sides of the cross main the weight is well over 240. NFPA 13 9.3.5.6.4 dictates that the zones of influence include all the branch and main lines tributary to the brace, but provides for an exception when the branch lines are provided with longitudinal braces. So, my questions are: 1) Is one longitudinal brace per cross main intersection adequate or is it necessary to provide a brace on both sides of the cross main? 2) Is my maximum spacing the same for branch lines as it is for mains, 80'? 3) Do I need to have the brace within 40' of the end of the branch line?
Thanks, Bob Knight, CET (208) 318-3057 [email protected] www.firebyknight.com _______________________________________________ Sprinklerforum mailing list http://lists.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)
