Air receiver hydro test pressure

[71713]

I've been told by a tank manufacturer that per code ASME stamped air receivers are to be tested at 1.3 times the maximum allowable working pressure. Is this correct or does the number vary depending upon size and pressure?

I'm looking at steel air receivers in the 600-1200 gallon range with working pressure of 200-260 psig.

 

[JoeTank]

The current edition of the ASME now uses a hydrotest pressure that is nominally 1.3 times MAWP. Prior to about 1998, the hydrotest factor was 1.5. So, the answer despends on when the air receiver was manufactured and which edition and addenda of the ASME VIII Code was used.

Joe Tank

 

[jte]

That's correct for a VIII Div 1 vessel, providing the design temp is low enough that no adjustment for allowable stress needs to be made. The 1.3 multiplier was changed from 1.5 in 1999 to correspond to the change in allowable stresses which occurred when the factor against ultimate tensile was changed from 4 to 3.5. Simply put, 1.5*3.5 / 4 = 1.3. That's code minimum; often a customer spec will specify a method which results in a higher hydro test pressure.

jt

 

[71713]

Thanks. This allowed me to explain why the client needs to spend more money on the higher rated tank.