What are the hydrotest limitations? 1

[iam42]

I have to Hydro Test a pipe spool (5000 psi Design Pressure) to 7500 psi,per B31.1, however, the pipe has 6000# fittings welded to it. Does this limit the hydro test pressure?

Thanks in advance.

 

[metengr]

iam42;
There is not enough information to answer your question. What is the material? Do you have ASME B16.34?

 

[iam42]

Metengr,

The materials are A-106 Gr C and A-105 fittings. The design temp is 450 F.

The pipe is 4" Non-Std Sch (.699 wall).

I do not have ASME B16.34.

Thanks

 

[metengr]

Yes, you should be ok using the 6,000 lb fitting for hydrotest at ambient temperature.

 

[eliebl]

ASME B16.11 gives guidance as to how to calculate the pressure rating of a Class 6000 fitting. There are differences between threaded and SW so be sure you are using the correct one for equivalent wall thickness.

EJL

 

[iam42]

Metengr,

How did you come to this conclusion. I would like to be able to make these decisions on my own in the future.

Thanks

 

[metengr]

Most of the ASME standards, like B16.5, 16.11, etc point back to B16.34 regarding working pressure by Classes for material groups. For SA 105 material, 4500 special class, you're looking at close to 11,000 psi working pressure.

 

[iam42]

Thanks Metengr,

I suppose it is another standard I need to buy.

Thanks again.

 

[metengr]

To answer your specific question regarding method, review specifically ASME B16.11, Paragraph 2.2, Pressure test capability. The minimum wall thickness of the piping, in this case SA 106 needs to be calculated for the design conditions. Based on this wall thickness, and the fitting type welded or threaded, use Table 2 in B16.11 to make sure that the class of fitting matches the calculated wall thickness;

for 6,000 lb fitting, pipe schedule is XXS for threaded fitting

for 6,000 lb fitting, pipe schedule is 160 for welded type