Consensus on maximum hydro-test pressure under circumstances (B31.3)

[k3_at_ke]

Situation:

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Currently we are being forced to follow a hydro-test procedure that derives its test pressures from the maximum allowable pressure the flange class can handle. This causes issues when the flange and butt joints tie into threaded connections. This problem along with others such as outlandish slip blind thicknesses and plain common sense.

Knowing that B31.3 does not have a maximum test pressure standard and the code minimum is 1.5x design pressure. I'm trying to research and find reason for sticking to the code minimum and using discretion when it comes to superseding the code. However no matter how much i look or how many issues are manifested from superseding the code i cant find a strong argument to be made.

 

[r6155]

Can you send us a drawing?, and more information.

Regards

 

[k3_at_ke]

Unfortunately no. This post references issues from multiple instances. However I do think it's worth mentioning often we deal with new to old pipe. So I'll have to dig into API 570

 

[LittleInch]

Can you explain this a bit more?

"This causes issues when the flange and butt joints tie into threaded connections" I don't understand.

What argument are you trying to make?

The test pressure in B31.3 is based on design pressure. This can be anything less than the max flange pressure rating. Is there a difference between design pressure and max flange rating?

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

 

[mk3223]

Currently we are being forced to follow a hydro-test procedure that derives its test pressures from the maximum allowable pressure the flange class can handle.

IMO, some options for the issue:
1. If this is the Client requirement, Can you say "NO"?
2. To test the system with the max allowable pressure of the flange class can be a good and efficient way for engineering design, construction and testing.
3. it may be benefit for the process/piping changes in the future projects.

 

[MJCronin]

In my opinion, this important question is posted in the wrong forum

You will get a better set of eyes if you post in the "Boiler and Pressure Vessel engineering" forum ...

MJCronin
Sr. Process Engineer