Piping Supports for Stainless Steel Pipe

[nikolastrojman]

Hi!

Based on your experience I would like to hear your opinion on this subject – piping supports for stainless steel pipe i.e. the problem of choosing the right material of piping support for stainless steel pipe.
My main concern is how to install/make a fix point for stainless steel pipe considering the problem of galvanic corrosion and avoiding contact between carbon steel and stainless steel.

Because of galvanic corrosion, contact between black and white material should be avoided.
From my experience to achieve this, clamped pipe shoe is used made of regular carbon steel and than a thin strip of PTFE material is inserted onto pipe to separate clamp made out of carbon steel and pipe made out of stainless steel.

The problem is that we also need anti-slip lugs to keep the pipe from slipping through the pipe support clamp. Tis lugs have to be welded to the pipe and they should be made out of the same material as the pipe, right?

Another approach would be to use the stainless steel for the whole support but than you have to weld white material support to the black beam on the steel structure where the support is located!
To solve this issue, there is an option to use black material for the base plate of the pipe support which can be welded to the steel structure, right? Or?

Do you know maybe how this is done usually on sites this days?

 

[XL83NL]

Another approach would be to use the stainless steel for the whole support but than you have to weld white material support to the black beam on the steel structure where the support is located!

Exactly. You'll have a galvanic break somewhere, somehow anyway. Would anything happen to the support, then its much cheaper to replace one pipe support than (part of) a whole SS piping spool.

That has been our apporach always. Although were focussed on new-build modular skids, and dont see much plant life over the years, so far this has been good practice. Our typical scope is DN25-DN100 piping, and for these sizes, a carbon steel support, which needs (hot dip) galvanization, is likely the same price as a complete SS support.

We dont use PTFE inlays or such. We just clamp the SS support to the SS pipe. Not issues with slip or whatsoever.

Huub
- You never get what you expect, you only get what you inspect.

 

[nikolastrojman]

We dont use PTFE inlays or such. We just clamp the SS support to the SS pipe. Not issues with slip or whatsoever.]

Does this mean that you whole support is made of stainless steel or only support base is made of CS? What kind of material is beam underneath the support made of?

 

[XL83NL]

Does this mean that you whole support is made of stainless steel or only support base is made of CS?

The whole support.

What kind of material is beam underneath the support made of?

Carbon steel, usually something like S235 or S355, either hot dip galvanized or coated.

Huub
- You never get what you expect, you only get what you inspect.

 

[1503-44]

Rubber vulcanised to a plate, or clamp, placed between the support, or on a clamp placed around,the pipe can also be effective.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Dhurjati Sen]

The thermal expansion properties of CS & SS are surprisingly different. Do keep this in mind before okaying the final design.

DHURJATI SEN
Kolkata, India

 

[EdStainless]

Rigidly clamping SS liens to a steel structures is rarely a good idea.
SS has double the thermal expansion of steel.
I tend to shy away from PTFE (creep) and rubber (degradation, high S content) and if going non-metallic use HDPE.
It is common to use SS saddles and clamps.
People make the transition to SS from CS at different locations depending on how they like building the supports.
In some cases it is just the saddle and clamp, in others the entire support, and some are in between.

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P.E. Metallurgy, consulting work welcomed