B31.3 Service Test 1

[prq123]

ASME B31.3 Piping code allows "short term" overpressure subject to the condition that the "in no case shall the increased pressure exceed the test pressure", refer section 302-2.4 (e) of B31.3. The question is if a piping system which contains category D fluid has been subject to a Service Test (as allowed per B31.3) at operating pressure (rather than hydrotest at 1.5x desgin presure) is it acceptable to take credit in ANY circustmance for the "short term" overpressure above the design pressure? Based on a strict reading of 302-2.4 (e), I would think the answer is "NO". Has anyone come across this before?

Thanks.

 

[BigInch]

IMO the answer is also a big no.

http://virtualpipeline.spaces.msn.com

 

[SeanB]

I would also agree and say no. This subject comes up a lot when we are revamping existing plants and have to increase design pressure - whether a re-hydro is required or not. In your case I would think that a re-hydro is definitely required since it has never been hydrotested.

 

[SamCheung]

What is the definition of Category D fluids?

 

[dcasto]

Per 345.1 (a) At the owners option, a Catagory D fluid piping maybe tested per 345.7, in lieu of the hydrostatic test.

345.7 Initial Service Leak test

The test fluid is the service fluid.

The pressure shall be gradually increased in steps until the operating pressure is reached, holding pressure at each step....


Remember in B31.3 there is no mechanical strenght test, only a leak test.

 

[SamCheung]

Is there a Category A, or B or C fluid and what are they? Thanks for the response.

 

[NozzleTwister]

Refer to ASME B31.3 for the catagories and definitions.

NozzleTwister
Houston, Texas

 

[SamCheung]

I have the 1996 Edition and the 2006 edition. Please advise which page has these categories, thanks.

 

[JohnBreen]

Hello prq123,

For the original poster, the answer to your question is no.

SamCheung, it is the responsibility of THE OWNER to determine which B31.3 Fluid Service shall apply. The owner needs to peruse paragraphs 300 (d) and 300.2.

"Please advise which page has these categories". No one page gives you all you want; you really need to carefully read the entire B31.3 Code.

You should begin by reading paragraph 300.2 Definitions. Look up the definition of "Fluid Service". You will see Code definitions of:

Category D Fluid Service
Category M Fluid Service
High Pressure Fluid Service
Normal Fluid Service

You should also read 392.3.5 regarding Cyclic Service and 300.2 (and the following references found there) regarding "sever cyclic service".

Please notice the we have provided Appendix "M" for the purpose of facilitating the owner's decision regarding the appropriate fluid service for a B31.3 piping system. You will see phrases used in appendix "M" for which you should go to paragraph 300.2 for definitions. The reference to the "base Code" implies piping that is in "Normal Fluid Service".

Regards, John.

 

[SamCheung]

I read them. Thanks, JohnBreen.

Regards,

Sam