https://www.dropbox.com/s/3qiwk9xwo6e65qa/trap.xls?dl=0
Here is a spread sheet I made ~25 years ago for calculating required section modulus-- right now it shows hanging 4" S10 centered in a 48" span and I figured 1x the weight of 15' of pipe +250 lb, and the required section modulus is .34. Brad -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Friday, June 05, 2015 1:50 PM To: [email protected] Subject: RE: suspending from wood members attached to structural I'd say that 13/2013, 9.1.1.2 (2) leaves that open to interp or argument. It says that points of support have to be adequate to support the system but doesn't tie that directly to the 5x mandate. So corner cutters can try to say that blocking is part of structure or not part of the hanger. I would argue that it's DEFINELY not part of structure unless it has been engineered as such, which would entail something more than 4x 10d nails as pipe fitters often use. If I furnish the load values to the SEOR, and he/she designs an attachment that in their professional estimation is adequately attached to the structure to bear a certain load, then the attachment is load-valued at whatever they say it is. But if you look to that blocking as a part of the sprinkler hanger assembly (and in my opinion that's what it is if it's not an engineered part of the structure, like a trapeze) then a conservative reading of that section would find that it has to meet the 5x rule. Keep in mind that the table that shows different pipe and angle section modulii is based on 5x WP + 250# and 2x lumber is conspicuously absent from that table. Also keep in mind that most truss manufacturers now publish sprinkler hanger and bracing installation guides that are chock full of engineered solutions, all of which are in compliance with best structural engineering practices and NFPA 13. Steve -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Damien Shannon Sent: Friday, June 05, 2015 9:55 AM To: [email protected] Subject: Re: suspending from wood members attached to structural Wouldn't the blocking only have to meet the 1x WP + 250# as wouldn't it be considered an extension of the building structure/a trapeze? Damien Shannon. On 5 June 2015 at 17:27, Steve Leyton <[email protected]> wrote: > 2x4 and 2x6 blocks have been casually used for years but we've learned > in the past 10 or so that they are NOT adequate by conventional > engineering standards and the 5x WP + 250# equation. For example, > TrusJoist has block details showing 4x4 members for piping up to 3 or > 4" but that's only for certain truss series and spacing that will > support the loads of larger pipe. You'll see a lot of details and > listing limitations for certain application of fasteners that are > limited to 2" pipe, which goes to the ability of the member to handle > the load, not necessarily the capacity of the blocking it's attached to when blocking is used. > > I think the best answer to your question as asked is: Yes - for > engineered products such as joists and trusses, consult the > manufacturer's installation and reference materials and/or consult > with the structural engineer of record. > > Steve L. > > -----Original Message----- > From: Sprinklerforum on behalf of JD Gamble > Sent: Fri 6/5/2015 9:12 AM > To: [email protected] > Subject: suspending from wood members attached to structural > > What are the general guidelines for attaching to wood members attached > to structural wood trusses. > > > > Example: Suspending 1 ΒΌ" steel sch 40 pipe using a 3/8 Sammy , ATR, > and a adjustable swivel hanger from a 2x4 nailed between two wood > trusses? (I don't see where this is an acceptable method of > installation, but don't want to miss the forest for the trees either) > > > > Surveying some existing work and trying to make a fair assessment of > additional hanger changes. > > > > Thanks, > > > > Life Safety Solutions of Sheridan > > > > JD Gamble > > [email protected] <mailto:[email protected]> > > (307) 763-3361 > > > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.org > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.org > -- *Damien Shannon* _______________________________________________ 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
