Pipe Support corrosion standard? 2

[Corduroy]

Hi, in regards to pipe supports, in particular Variable and Constant Spring supports, are there any inspection standards, like NACE has for steelwork and pipe?

A example, a 20 year old Constant Spring support that is still operating as designed, however there is a high level of corrosion around the load bearing areas. How would you determine if it would need replacing? And how long can it remain in service?

If there are no standards, can anyone direct me to a website or document that would help?

I can't rely on opinion or "gut feel", it's to be based on some "facts".

I hope someone can help.

 

[racookpe1978]

The threat to your pipe support (a pre-loaded, spring-balanced, pivoting arm, canned-movement constant weight-type support, right?) is not that the corrosion will "break" the whole support, but that one of two things will happen (have already happened! )

1. The rust is in a structural or load-bearing area (like the link pin or the bolts or the sprint can cover or pipe clamp bars and bolts where these fail and the load falls. (The first pipe support fails, the rest are overloaded, then they fail or the pipe sags and fails to drain properly.

2. MUCH MORE likely. The "moveable" internal parts of the spring, the balance arm, the pivot point, vertical hanger piece that carries the load against the pipe movement are already rusted shut and your very expensive constant tension spring hanger is a mass of congealed rust that fails to carry ANY load at medium, is too short at low temperature and too long at high temperature, has stopped any movement at any temperature, and presses BACK with its pre-spring movement against the pipe at low temperature, thus damaging all of the adjacent hangers since they are now working "backwards" against the fail hanger at low, medium AND high temperatures.

Your loacl spring hanger "sales engineer" is going to want to sell you new hangers, no doubt. But he will also be able to inspect the hangers 9if access is available) and start with a project list.

 

[bimr]

This company should be able to assist you:

http://www.pipingtech.com/services/siteserv.htm

 

[Corduroy]

Thanks for replying. I am aware there are companies that do site inspections. I'm more after standards, procedures etc that I could use and gain knowledge from.

What I have found, is that there is not a lot of information around and appears that the actual pipe support fabricators have their own in-house standards rather than anything written by the likes of NACE, ASTM, ASME etc, which is why I have come on here looking for help or confirmation.

 

[bimr]

In the example in your original post, you can use NACE to evaluate the steel corrosion. Otherwise, you need to procure expert judgement. Expert judgement is more than a "gut feel" or "opinion".

One can't expect that the person is going to be an expert from just reading a book or standard, especially if it is someone with little experience in the task.

 

[MJCronin]

Its quite lengthy, wordy etc. But the document link below may be of use to you.

It is the summary criteria endorsed by the DOE for Nuclear Power Plant pipe supports:

http://energy.gov/sites/prod/files/...Nucl_Fac_Const-Pipiping_and_Pipe_Supports.pdf

MJCronin
Sr. Process Engineer

 

[bimr]

Inspection Practices for Piping System Components, API RECOMMENDED PRACTICE 574