The way we view that is, if you have a pipe from a cross main feeding a
sprinkler or sprinklers - this would require a restraint - it is a branch
line.
Branch lines supply sprinkler(s) directly or through sprigs, drops, return
bends, or arm-overs - only branch lines require them per 9.3.6 so the
sprigs, drops, return bends, or arm-overs don't.
Bobby Gillett
Project Manager
[EMAIL PROTECTED]
(731)-424-0130
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Thursday, June 19, 2008 7:57 AM
To: [email protected]
Subject: RE: Restraint of Branch Lines
A branch line can be a single head per the definition in NFPA 13. Does
this mean each arm-over, drop, or return bend regardless of length must
have a branch line restraint? It seems sprigs are given special
attention in Chapter 9 but the other categories of branch line are not.
I guess I'm getting back to the confusion over the definition of a
branch line. From the feedback it seems no one is providing restraint
when a single head is involved.
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
-------- Original Message --------
Subject: RE: Restraint of Branch Lines
From: "Thom McMahon" <[EMAIL PROTECTED]>
Date: Wed, June 18, 2008 4:50 pm
To: <[email protected]>
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
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