use pipeshoes in bridges? 1

[europipe]

I know there are very experienced guys amongst you,
I want to know what you think about using pipeshoes on uninsulated lines in steel pipebridges.
I tried to search former threads but couldn't find it.
Your insight would be very appreciated.

 

[pennpiper]

The following is from the

http://www.pipingdesigners.com

website under pipe supports.

Shoes

This device is required to raise a hot insulated line off the structural support surface. The reason for this is to prevent damage to the insulation as the pipe expands as it heats up and shrinks as it cools down. For pipe sizes 3" thru 10" a simple inverted "T" shoe with a flat bottom plate and one (single) vertical plate should be used. For pipe sizes 12" thru 18" a shoe with a flat bottom plate and two (double) vertical plates should be used. For pipe sizes 20" and larger consideration should be given to the addition of a Load Distribution Plate where thin wall pipe may exist. The material for pipe shoes will normally be carbon steel. However, where the pipeline is an exotic material this would cause a weld of dissimilar metals to exist where the shoe is attached to the pipe. For shoes used on exotic materials only the bottom plate is carbon steel. The (single or double) vertical plates are made of the same material as the pipe. For piping that requires post weld heat treating (PWHT) after fabrication the shoes must be added by the shop. Some company's (engineering and client) will also require the use of shoes (with the Load Distribution Pad) for all uninsulated 24" and larger piping where the pipe wall is below a certain limit.

I hope it helps.
Please feel free to go to that website and read all the articles posted under Training, Tips and Standards

 

[europipe]

What is your opinion on using shoes under non-insulated pipelines?

 

[pennpiper]

To finish my thought. A Bridge is nothing special as far as the pipe is concerned. It is just a different type, version or configuration of a primary pipe support.
If the pipe is insulated it should be rested on a shoe to protect the insulation at each support contact point when crossing the bridge structure.

 

[pennpiper]

"using shoes under non-insulated pipelines"
I have to ask "Why would you (or the project, or the client) want to consider this?"
Is this a corrosion issue?
Is there limited access to inspect and or paint pipes and steel because it is on a bridge?

This is normally a project by project decision. I have seen it done and it is very expensive. It is a project cost issue that the client must be aware of and approve.

I would not want to do it on a project wide basis, but I could see considering it used and limited to only the bridge portion where it crosses over a river.
If shoes are to be used on all lines only on a bridge crossing then the TOS (Top of Steel) for the pipe support level on the bridge must be lower (Height of shoe) than the other pipe support TOS.
Then you have an added shoe height for lines that normally on shoes and now are on a bridge with a lower TOS.
See it gets complicated.

I would not recommend it.

 

[europipe]

You have to do something between bridge and pipe to prevent damage.
I've seen worn out pipes because of continously shrinking and expansion.
Also when the material is different or when a normal cs line is painted there is some action needed.
Thanks for your opinion.

 

[pennpiper]

You asked a general question and I gave you a general answer.
Now let's get specific. Give us some information to work with.
Where is this plant or bridge located?
What kind of plant or process are we talking about?
What is in the lines going over the bridge?
What is the ambient temperature?
What is the maximum operating temperature of the line (or lines) going over the bridge?
What do you do about "worn out pipes because of continuously shrinking and expansion" of pipes that are not on a bridge?

You just might get a different answer.

 

[MJCronin]

penn, euro....

This UK firm offers pipe shoes specifically for service where moisture build up would cause long-term corrosion. They seem to be geared to the petrochemical morket as opposed to other pipe shoes that are geared to the "hot thermal" market.

See this link:

http://www.atlantic-supports.co.uk/ASEProductsAntiWearUPS.htm#UPSProductApplicationNotes

They mitigate the affects of stray galvanic corrosion and also cover slight thermal movements.

FYI ...???

Comments ?

-MJC

 

[europipe]

Penn, I’m sorry you seem to be a little offended.
But it is only my intention to get a general answer.
I’m hopping from project to project and all companies have different solutions for the same situation.
So I wanted some reactions.
This is not a specific question.
I thank you for your valuable time spend on this thread.

 

[STYMIEDPIPER]

I recently worked on a project at a tank farm. The client took a proactive approach and requested all pipes on the bridge to have pipe shoes (both insulated and non-insulated headers). The reason for this approach was that the product stored and distributed changed periodically per market demand. Hence, the client wanted to be able to insulate the line in the future (if required) with little disruption and down time. Adequate spacing on the the pipe bridge was required to accommodate the future insulation. The client realized that spending a liitle additional funds upfront may have significant savings in the future.