1.5 XMAWP or 1.3X MAWP XLSR ?

[darrenyee88]

Which one to use for hydortest. Why when we use 1.5 X MAWP , we don't consider the LSR ? Can someone advise me.

 

[JohnGP]

darrenyee88, you haven't stated which code you are testing against, but given this is the Boiler and Pressure Vessel engineering forum I will take a stab at it being ASME VIII Div 1. If that is the one, then there is no requirement for testing to 1.5*MAWP - the minimum requirement is 1.3*MAWP*LSR. It may be that testing to 1.5*MAWP would satisfy the code minimum requirement, but you would have to check.
Regards,
John

 

[darrenyee88]

Hi John,

Thanks. Understood that the min require for ASME Sec VIII Div 1 is 1.3*MAWP*LSR .

I was told that if we use 1.5 X MAWP , it will exceed the yield strength of the material which is not advisable. Please advise if my explanation is correct?

Regards,
Darren

 

[TGS4]

It may or may not exceed yield. You would need to perform some calculations in order to come to that conclusion.

There is generally a minimum test pressure (mandated by the Code) and a maximum test pressure that would cause permanent damage.

 

[A clark]

The 1.5 X mawp requirement is from ASME Section I. Read PG-90. Section limits the stress to 90% of yield.