From 13-2016:
9.3.5.11.5 All parts and fittings of a brace shall lie in a straight
line to avoid eccentric loadings on fittings and fasteners.
The above means, to me anyway, that it is NOT ok to kick the
longitudinal brace out at an angle as seen in plan view. In this way I
think that is an angle that does matter, but Ken cleared it up by
saying the brace pipe has to be parallel to the main pipe.
As always, I am willing to stand to be corrected,
Brad
Quoting "Kyle.Montgomery" <kmontgom...@aerofire.com>:
I knew where you were going, Steve, and I agree that this is a good
approach. We’ve gone this route in the past, but when you get to the
stage of the job where I’m usually involved (closer to construction)
and everyone has contracts for construction, it can sometimes be
contentious as far as who would provide and pay for this additional
engineering. So I was looking for ways to control our own destiny,
so to speak.
Thanks for everyone’s input.
-Kyle M
From: Sprinklerforum
[mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of
Steve Leyton
Sent: Friday, July 28, 2017 3:25 PM
To: sprinklerforum@lists.firesprinkler.org
Subject: RE: Longitudinal Bracing Question
What he said. To clarify my earlier comment – I did not intend to
suggest that you could use the trapeze values in NFPA 13 for hangers
and apply them to EQB anchorage. However, we have worked with our
structural engineers on previous projects to design for similar
conditions where the shear load bearing value of the strut (notice I
just said strut instead of trapeze) was specified by the SEOR and
was adequate for the applied loads of the specific braces we needed
to anchor. It CAN be done, but as Ken says, it can’t be done by
simply using the trapeze section moduli published in NFPA 13.
Steve L.
Back Peddling, CA
From: Sprinklerforum
[mailto:sprinklerforum-boun...@lists.firesprinkler.org] On Behalf Of
Parsley Consulting
Sent: Friday, July 28, 2017 12:53 PM
To:
sprinklerforum@lists.firesprinkler.org<mailto:sprinklerforum@lists.firesprinkler.org>
Subject: Re: Longitudinal Bracing Question
Forumites,
Let's clarify a couple of items here. [All references to the 2016
edition, and all emphasis is mine]
* Longitudinal bracing on mains must be spaced no more than 80'
apart, per 9.3.5.6.1
* The distance from the end of the line and the last (or first)
longitudinal brace must no exceed 40', per 9.3.5.6.
* Your first longitudinal brace could be as much as 40' from
the end of the pipe run.
* The structural components of the building must be able to
resist the added seismic loads, per 9.3.5.1.2
* This is something the building structural would have to
provide, as it's not something a sprinkler contractor should attempt
without some training and experience in structural engineering.
* A trapeze installed per NFPA 13 guidelines is not intended to
address loads other than gravity in the vertical orientation, and
any resistance to horizontal movement would have to be designed by a
structural engineer.
* As long as the brace member (pipe, rod, flat, etc) does not
exceed the limits on the length imposed by tables 9.3.5.11.8(a)-(c)
having it be four feet to the nearest bar joist should be no problem.
* The only "angle" which really applies in providing
longitudinal bracing is the measurement from vertical. That angle
must be at least 30° and have a maximum of 90° from vertical (which
is perfectly horizontal, and would make the brace parallel to the
pipe.
The addition of another flexible coupling on the main could create a
further requirement for additional lateral bracing within 24" of the
flexible coupling per 9.3.5.5.9.
I hope that provides some guidance.
As I am a member of the hanging and bracing committee of NFPA 13,
please see the disclaimer below.
sincerely,
Ken Wagoner, SET
Parsley Consulting
350 West 9th Avenue, Suite 206
Escondido, California 92025
Phone 760-745-6181
Visit our website<http://www.parsleyconsulting.com/>
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
It should be noted that the above is my opinion as a member of the
NFPA Automatic Sprinkler System Hanging and Bracing Committee in
accordance with the NFPA Regulations Governing Committee Projects
and should therefore not be considered, nor relied upon, as the
official position of the NFPA or its Committees
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