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RE: Pipe Support Detail

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Rich,

I have no prejudice towards rollers. I have not used them so far.

Assuming the pipe is installed at 70 F, the maximum movement at either ends of the 600 ft run would be a little less than 2". If there is room to provide expansion loops within the end third points of the pipe run, you may be able to get rid of the  the excessive longitudinal movement at the ends which means you may not need the anchors at the ends.  If you use a pipe stress program, you can quickly look at various scenarios.

Personally, I don't like pipe supports to be anchors.  Also, placing an anchor close to an equipment will generate significant loads at the equipment nozzle, because the pipe between the nozzle and the anchor is prevented to move with temperature changes.

With the pipe 20' above floor, the pipe supports will be 20' tall. The support will behave as a cantilever under longitudinal load. If the tip deflection due to the longitudinal load is greater than the thermal movement of the pipe at the support, the longitudinal load will be relieved and will not be seen by the support.

Rajendran

Rich Lewis <seaint03(--nospam--at)lewisengineering.com> wrote:
Rajendran,
 
Operating temperature â?? 100-150 F â?? warm water
Length â?? over 600 ft., no insulation
Loops â?? Expansion
Anchors â?? resist expansion at equipment at ends
 
Iâ??m considering using a Teflon pad or a roller bearing type support form the Cooper catalogs that I was referred to in other posts.  I was going to check with Cooper for the relative price differences.  I would think the Teflon slide would be more expensive.  Any reason why I shouldnâ??t use the roller application?
 
Rich
 

From: Padmanabhan Rajendran [mailto:rakamaka(--nospam--at)yahoo.com]
Sent: Wednesday, February 15, 2006 7:47 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Pipe Support Detail
 
1. What is the operating temperature?
2. Why do you have the loops in the layout?
3. Why do you have to provide anchors at the ends?

A teflon pad has a coefficient of friction of about 0.1 to 0.15 (the actual value depends on the contact pressure). Use of teflon pad will lower the longitudinal force you are referring to. You may want to do a google search for Fluorogold to get some data on teflon pad.

If you provide answers to above questions, I may come up with some suggestions.

Rajendran

Rich Lewis <seaint03(--nospam--at)lewisengineering.com> wrote:
I read some about this subject in the archives but couldnâ??t find the answers to my questions.  I have a situation where I need to support two 12â?? and one 14â?? diameter horizontal runs of water lines about 20 feet above the floor.  I am not able to hang them from the roof structure so I need to design a frame to support them.  I will have anchor frames at each end and an expansion loop in the middle.  Right now I am looking at the typical intermediate frame supporting the pipes about 23 feet on center, not the anchor frames.  I was considering a Tee type frame or a vertical stick frame with outriggers to support the pipe.  I prefer the Tee system because I could more or less balance the loads across the top.  I was told if I could stack the pipes vertically instead of horizontally side by side it would help with the expansion loop.  Using a stick type frame with outriggers puts all the load eccentric to the column on the same side.
 
I think what will influence my final decision will be the type of connectors of the pipe to the frame.  There is no insulation on the pipes.  As I see it I need some type of slide or roller connection to allow the pipe to expand and not push the frame.  I looked at bare steel friction sliding and decided it was too great to fight with the frame.  I looked up a sliding type pipe connection on the internet to set the pipe on the top cross member of the Tee.  I was thinking that maybe if I hung them from the beam instead of sitting on top I could have a swivel hanger type connection.  If I use one of these though I would think I need a swivel at the pipe bracket and at the beam hanger nut location.  I didnâ??t see any like this.  As I see it, this would also put a slight rotational moment around the support column.  I saw there are roller type swivel connections.  This would take out the horizontal component of the pure swivel.  Unfortunately there load carrying capacity was lower than I need of about 3,500 pounds.
 
Iâ??m looking for suggestions in two areas from engineers who have experience in pipe support:
  1. Is it better to have the supports sitting on a cross beam or hung form a cross beam?
  2. What connection material would be recommended to allow the pipe to move longitudinally relative to the support frame?
 
Thanks for any insight.
 
Rich
 
 
 
 

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