Tom, I might be approaching this all wrong, but ........ The required section mudulus for 6" sch. 10 pipe at a span of 6'-0" is .71 and the required section modulus for 2½" pipe at a span of 10'-0" is .41 .41 + .71 = 1.12 The available section modulus for 6" sch. is 4.35. The table 9.1.1.6.1(a) is based on a maximum allowable bending stress of 15 ksi and a mid span concentration load of 15ft. of water filled pipe, plus 250 lbs. I think you can hang your 2½" pipe at a hanger spacing of 6'-0" (for the mid span concentration load) i guess the only thing to confirm is not to exceed the bending stress of 15 ksi which might not be a problem since you are cutting the load a little less than half.
George Medina Jr. -----Original Message----- From: tom poisal <[email protected]> To: sprinklerforum <[email protected]> Sent: Mon, May 31, 2010 2:43 pm Subject: Fwd: trapeze hangers ---------- Forwarded message ---------- rom: tom poisal <[email protected]> ate: Mon, May 31, 2010 at 5:40 PM ubject: Re: trapeze hangers o: [email protected] en, according to NFPA 13 (2002 handbook) I believe 9.1.1.6 is pretty clear n that my modulus is 0.41 thru 0.44 for 2 1/2" pipe at a span of 6' (the urlin spacing) and 6" sch 10 pipe is within the Table 9.1.1.6.1 (a) table, nd it clarifies the hanger size 9.1.1.6.5 so I use 6" rings at both ends? hat is what I am trying to clarify. n Mon, May 31, 2010 at 5:27 PM, tom poisal <[email protected]> wrote: > george the six inch main is directly attached to an 8" purlin, the structural engineer has no interest in my hanging weight, as at the start of the project i was willing to give him panel point loads (weight of water filled +pipe), anyway it is not trapezed, the purlis are 6' o.c. so I'd rather keep the hose line main back against the wall like the feed main.....keep out of the racks way..... On Mon, May 31, 2010 at 5:17 PM, ParsleyConsulting < [email protected]> wrote: > Tom, > > I don't know for sure but I would believe that such an installation > would be outside of the listing of the rings, and I would imagine the > manufacturer's would not stand behind such an installation. You might > give one of them a call on Tuesday and ask if that's something they can > support, no pun intended. > > It would also seem to be at odds with the letter of the standard, which > requires pipe hangers to be attached directly to the structure., as > noted in 9.2.1.3 ('07 edition). I would also suggest that you may run > into structural problems with the lateral deflection of the 6" main by > adding loads to it that are taken into consideration, similar to the > lateral deflection limits that are applied for seismic bracing. > > If this is the only means you have to support the pipe I would not be > comfortable in using such a method unless I had a structural engineer > sign off on it, as noted in 9.1.1.2. > -- > PARSLEY CONSULTING > Ken Wagoner, SET > 760.745.6181 voice > 760.745.0537 fax > [email protected] <mailto:[email protected]> e-mail > www.ParsleyConsulting.com <http://www.ParsleyConsulting.com> website > > IMPORTANT NOTICE: This correspondence is not a Formal > Interpretation issued pursuant to NFPA Regulations. Any opinion > expressed is the personal opinion of the author and does not necessarily > represent the official position of the NFPA or its Technical Committees. > In addition, this correspondence is neither intended, nor should it be > relied upon, to provide professional consultation or services. > > > > > > tom poisal wrote: > > I'm running a grid which consists of a 6" near main, 4" far main with 2 > > 1/2" gridded lines for a warehouse, I also have to supply several hose > > stations from a separate system, can I run the hose supply line (2 1/2") > > direcetly below the 6" line using - 6" rings, 1/2" rod and then 2 1/2" > ring > > and double up on my 6" main hanger spacing? (7' o.c.) to hang the 2 1/2" > > below the grid main? > > > > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected]<to%[email protected]> > (Put the word unsubscribe in the subject field) > -- Tom Poisal, CET -- om Poisal, CET -- om Poisal, CET ______________________________________________ prinklerforum mailing list [email protected] ttp://fireball.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) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.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)
