API 5L general query 1

[vasayam]

What % of SMYS should be used to calculate hydrostatic test pressure for API 5L Gr.B PSL2 (SAWL) Pipe?
Whether it's 60% of SMYS (Standard Test Pressure) or 75% (Alternate Test Pressure)?
What's difference between these 2 pressures and where to use it?

Thanks and regards,
Sayam

 

[metengr]

What is the code of construction for the pipeline?

 

[vasayam]

The description is "Pipe, SAWL, ASME-B36.10M, BE, API 5L Gr BNS PSL2 UOE mfg process, NACE MR 01-75/ISO15156" and size is 20" & above.

 

[metengr]

vasayam;
The code of construction in this case is not the material specification, API 5L for fabrication, it will be the intended service application of the pipe. For example, a code of construction for piping could be ASME B31.3 or ASME B31.8 or other. The construction code specifies hydrostatic test requirements in addition to client specification requirements.

 

[vasayam]

The code of construction is ASME B31.3.

 

[metengr]

Ok. Please review below,
345.4.2 Test Pressure in the 2008 ASME B31.3. All of the information is there to determine hydrostatic test pressure.

 

[grampi1]

The issue is the pipe mill is not required to test to a high percentage of SMYS and so may be a lot lower than field hydrotest pressure. Users should supplement 5L requirments and be specific about what % of SMYS they require the pipe mill to test at.

 

[vasayam]

The question is
What's difference between Standard Test Pressure and Alternate Test Pressure?
How to apply it on API 5L?

 

[SJones]

The difference is that the alternative is higher! How to apply it is to specify it in the purchase order. Unfortunately, API 5L, 7.2 appears to have omitted to provide a reminder to the purchaser that they need to specify which hoop stress percentage is to apply. If you are enquiring as to whether it should be applied, that is dependent upon your belief in whether a higher stressed mill hydrotest increases the reliability of the pipe at the time of installation.

Steve Jones
Materials & Corrosion Engineer

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