I think your missing the point! Tension only systems need to be restrained
in all directions. Do you think that a seismic event will only move the pipe
in one direction? What generally keeps the tension on the one brace, is the
tension of another brace in the opposite direction. If you use a tension
brace to keep a pipe from moving away from a wall, you must have a second
brace to keep it from moving towards the wall. If the pipe moves and you get
slack on the brace, its pretty apparent that it's not properly braced in the
opposite direction.
Get help from the MFG. and re-read your installation guide.
Thom McMahon
Firetech, Inc.
2560 Copper Ridge Dr
Steamboat Springs, CO 80488-2136
Tel: 970-879-7952
Fax: 970-879-7926
----- Original Message -----
From: "Todd Williams - work" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, February 02, 2007 4:25 PM
Subject: Re: Seismic bracing - wire rope
Think about this for a moment. What would keep tension on the wire? One
thing, the weight of the pipe. This means that the wire has to be allowed
to carry a certain amount of the weight of the pipe. I would check the
breaking strength of the wire, but I would assume that it could probably
hold more than you think. The solution may be as simple as loosening up
the knerl nut a turn or two (unless it's 40 ft in the air; then nothing is
simple)
As to what would cause it to loosen up over time, what about thermal
changes from when it was installed to now. Was it installed and set cold
and is now in a heated building? If so, the wire might have expanded
differently than the rest of the system, causing slack. Also, have the
upper or lower supports secure? Is there evidence of damage?
At 12:47 PM 2/2/2007, you wrote:
Generally The "Wire Rope systems are "Tension Only" systems. These are
intended to be under tension in all directions at all times to prevent
movement of the pipe. If you have "Slack" you aren't preventing movement.
Call the MfG of the product your using and get their take on it. It's
their engineering that the product installation is based upon, have them
review the installation and placement for this application.
Thom McMahon
Firetech, Inc.
2560 Copper Ridge Dr
Steamboat Springs, CO 80488-2136
Tel: 970-879-7952
Fax: 970-879-7926
----- Original Message ----- From: "Richard Battershell"
<[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, February 02, 2007 10:06 AM
Subject: Seismic bracing - wire rope
How much , if any, slack is allowed in wire rope used for seismic
bracing?
Our fitters install the product we are using according to the
manufactures
directions and recommendations, but after a period of time (days/weeks)
you
can see slack in some of the braces particularly the lateral bracing. I
believe this is caused by the pipe getting knocked around by other trades
during the installation of their work. In any case the fire marshal has
questions that I need to be prepared to answer. Please help.
Thanks in advance.
Richard Battershell
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Todd G. Williams, PE
Fire Protection Design/Consulting
Stonington, Connecticut
860-535-2080
www.fpdc.com
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