Hi all,

1. for service that contain some H2S (sour), if you're using the right NACE materials (e.g. SA 106 B), right gasket rings (stainless), valves and fittings that are ordered to meet NACE, and the welding procedure is hardness qualified to meet NACE (by Vickers hardness test), will there be a reason to require post weld heat treatment, or should it only come in if the material type changes to higher strenght or non-nace material?

2. B31.3 technically does not have low pressure exemption for hydro-testing or NDE for normal fluid service, Will there be any engineering or low risk reason for one to exempt some section of a facility piping from hydrotesting based on things like  (a) very low pressure of 50psi, 20psi, 150psi, (b) location class or remote locations, etc?

Thanks for you input...

As much as possible, do it right the first time...

1. Sour service equipment is usually a requirement of the owner to prevent SSC.
2. There are no exemptions for what you described..

Reread the code, but this time do it cover to cover, not a key word search.

1.) See Tables 331
2.) Low risk scenario is a nontoxic, nonflamable fluid with a pressure less than 15 psig.  That is low risk.  If so, exempt yourself from coverage under B31.3, because B31.3 specifically excludes coverage of that low risk scenario.  If you have somthing else, it's not low risk.  H2S settles that possible argument.

You do not have to leak test with water, under very specific conditions.  The first being that it is nearly impossible to do so using water.  Basically, if there is any way that you can test with water, you must test with water.
See Section 345 for the other conditions.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

What rustbuster was probably trying to say for item 1 is:

Provided that the requirements of ISO 15156-2 have been met, there is no requirement to undertake PWHT unless it has been specified as applicable by the end user.  This is clearly addressed in A.2.1.4 of Part 2, Technical Circular 1, 2011

If the end user has not mandated PWHT, it will only be necessary when the requirements of ISO 15156-2 cannot be met without it.

The above assumes that this is an upstream application and that 'NACE' is not NACE MR0103.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04
 

Thanks all,

@ SJones, yes it is NACE MR0175 (Upstream and some midstream)
@BigInch: what in my question suggest that I have not read the code or did a word search?

Thank you.

As much as possible, do it right the first time...

It appeared to me to be rather obvious that you didn't read the scope.  B31.3 covers all pipe design within its scope in order to minimize risk.  Why have a code to cover non-risky things.  All things that it covers present some element of risk considered great enough to justify it being included in the code.  Things that could be covered by B31.3, design of process piping, but are exempted, or otherwise not covered by B31.3, such as equipment items, by definition of scope, logically also define the B31.3 limit of responsibility and risk envelop.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso