Heat Treatment for P1 to P1 Weld

[Abu Bakar]

Hi, kind of stuck with the ASME 31.3 requirement here.

In ASME 31.3, there is no clear definition on how much is the pressure rating for the line to be considered as high/low pressure. The closest statement I can found is, the definition of high/low pressure line will be based on owner definition (ie the party that's doing the design)-excerpt as in photo attached.

- CHAPTER IX K300 High Pressure Piping

Now, in the case of high-pressure line is defined by owner, the rule in CHAPTER IX should be applied.

ASME 31.3 mentioned there's exemption for mandatory heat treatment, if condition stated in table 331.1.3 is satisfied (as in picture attached)

- CHAPTER V 331 Heat Treatment

If we consider the line is high pressure, and we are following the rule in CHAPTER IX, it stated that the exemption for mandatory heat treatment as stated in table 331.1.3 will be voided if the thickness exceeds 19mm.

CHAPTER IX K331 Heat Treatment

Now my confusion is, correct me if I am wrong, my understanding is if we are following rule in CHAPTER IX, all P1 to P1 Weld will need to be heat treated when the thickness exceed 19mm, and the exemption can only be applied to the line with less than 19mm thickness.

 

[LittleInch]

The newer versions of B 31.3 don't state this anymore, but previous editions used to state high pressure was generally regarded as beyond the range of ASME B 16.5 Class 2500 flanges for your P & T.

I think your interpretation is correct.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SJones]

The 19 mm thickness limit still remains in Chapter IX, so the interpretation is correct. The OP might also like to think about the lax exemption of Table 331.1.3 as discussed by EEMUA in EEMUA Publication 235.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.