Fittings Corrosion and B31.G 1

[CORPMEX]

Hi you all,

Can I apply B31.G calculations on fittings (elbows, tee´s, etc) ?

 

[gr2vessels]

The criteria for evaluation of corrosion defects takes in account the pipe radius/diameter and the wall thickness, which also applies to elboes and tees. I cannot see reason for excluding those fittings.
cheers,
gr2vessels

 

[BeardedBob]

Unfortunately in my opinion you shouldn't do this.

The B31.G method was based on tests and modelling of straight pipe loaded by internal pressure, giving a fairly simple stress pattern. Fittings have more complex geometries and stresses and will often have significant external loads which the B31.G procedure does not include. For these reasons using B31.G may be unsafe.

You could try using API RP 579, which gives some guidance on assessing corrosion in more complex geometries. For a critical component you consider stress analysis. Annex G of BS 7910 gives some guidance on how to carry out a finite element analysis of corroded components.

What is your application?

Regards,

 

[LSThill]

BeardedBob (Mechanical)

Not API RP 579, but July 2007: API 579-1/ASME FFS-1 for State of the Art FFS Assessments. The FFS methods in API 579-1/ASME FFS-1 are quantitative engineering evaluatons that demonstrate the structural intergrity of an in-service component that is flawed or damaged.



L S THILL

 

[SaCaZu]

I've been studying this code and I'd like to know if:

Is it a conclusive method to determine if a pipeline can be put out-service or repair according to results obtained during its analisis or procedures?..acording to limitations and scopes are clearly understandable that not...but I thank if anyone knows some another code that reinforces the results based on Code B31.G but that not be API RP 579 (due to its complexity).

P.D: I guess that it's solely conclusive when a pitting which current measured thickness is equal or greater than 80% with respect to nominal thickness.

Thanks in advance.

 

[gr2vessels]

SaCaZu,
Please stop replying with questions and topics unrelated to this thread. Please post your question on a new thread and please read the rulings of use for this forum.
regards,
gr2vessels