Hydrotesr UG-99 or client specification which rules?

[Resegone]

Good evening everyone. I got a problem with my new project for my new customer.
In his specification of pressure Vessel design he definines two ways for calculation of the hydrotest pressure: UG -99 (b) or an equation added to this specification. The two value obtain are quite different so which One rules over the other?

In his specification he doesn't define the importance

 

[DVWE]

I don't mean to sound rude, but you should take care of this issue with your customer, not on some internet forum.

The devil is in the details; she also wears prada.

 

[GD2]

Resegone,

How is the equation looks like?

GDD
Canada

 

[DekDee]

Agree 100% with DVWE's response.
One thing to always remember is the Owner / Client / Designer can apply requirements that are more stringent than the code / standard but they cannot apply requirements that are less stringent.

 

[SnTMan]

And complying with added client requirements does not obviate meeting Code rules as well.

Clarify with the client.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Resegone]

I agree with all of you, but this problem Is born due to my customer that cannot reply to my query and the only thing he said is to follow the specification.

The equation Is the follow: H = 1.3 * DESIGN PRESSURE * ( ALLOWABLE STRESS VALUE AT HYDROTEST TEMPERATURE / ALLOWABLE STRESS VALUE AT DESIGN TEMPERATURE)

This two value must be selected from the tablet in ASME B31.3

Just for info with Ug-99(b) i obtain a value of almost 45 kg/cm2(g), instead with the equation i obtain 55 kg/cm2(g)

As you can see there Is a quite different between the two values

 

[XL83NL]

Does the client spec require to obtain these 2 values (ALLOWABLE STRESS VALUE AT .. TEMPERATURE) from B31.3, for an VIII-1 application?

Huub
- You never get what you expect, you only get what you inspect.

 

[DVWE]

Tell your client the project will be put on hold until your question gets answered. I bet you’ll get timely response.

The devil is in the details; she also wears prada.

 

[r6155]

Can you tell us how this affects you?

Regards

 

[SnTMan]

Inform the client you will comply with the exception the allowables will be per Sec VIII, Div 1. "We are proceeding."



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[GD2]

Resegone,

You are not breaking the code rules if you are testing at higher pressure above the minimum requirement. The code rules are minimum.
The difference between the test pressures are due to different allowable stress values for different codes with different safety margins.

Just make sure that you don't exceed the yield strength of the weakest material in the vessel. Usually, limited to 90% Yield Strength.


GDD
Canada