per UG-1 of ASME Section Viii div. 1 , the div have been formulated on the basis of design principles and construction practices applicable to vessels designed for pressures not exceeding 3000 psi.

Appendix 1 of ASME Section VIII Div.1 has provided formula for thick wall vessel. (if using A516-70 the pressure has to be > 7700 psi)

what is the thickness calculation formula to be used and additional design principles and construction practices required if the pressure is between 3001-7000 psi ?

i hv tried to input 4000 psi for the pv design in pvelite software, seems the formula used for calculating the thickness is formula used for <3000 psi. is this still compliant to ASME Code if there is no further /additional design principles and construction practices provided.

Hello STL

Yes, the 3000 psi is the recommended limitation placed on pressure. However Division 1 of ASME Section VIII does not preclude higher pressures. If higher pressure are to be used, then the user is cautioned to take other precautions to ensure the design is safe. The code does not give any details concerning the 'other precautions'. Appendix 1 requires that thick shell theory be used when the pressure exceeds 0.385SE, because the hoop and longitudinal stresses at the inside surface of the shell exceeds those determined by the formulae in UG-27 ff.

Generally, if the thickness of the shell does not exceed 10% of the shell inside diameter, the formula for a thick cylinder (lame) yields a close result to the formula found at UG-27.

Now, as you have pointed out, a pressure of 4000 psi for SA-516 70 does not exceed the 0.385SE limit, therefore PVElite does not use the thick cylinder formula from Appendix 1. At this time, there is no provision in the PVElite software to force the programme to use the thick cylinder formula, as the programme simply follows the rule stated in Appendix 1.

As the ASME Division 1 rules do not give any further guidelines for pressures exceeding 3000 psi, no further procedures have been included in the sofware.

We recommend that you check the stresses using the thick cylinder formulae as a precaution to ensure the stresses in the table of maximum allowable design stresses are not exceeded.

Also, please remember that in general, carbon steel components over 1.5 inches thick required to be 100% radiographed, and subject to PWHT.

Dear STL,

In regards to additional requirements to be satisfied when design pressure exceeds 3000 psi, here are some references,

ASME Sec. VIII Div.3- Rules for Construction of Pressure Vessels Division 3-Alternative Rules High Press Vessels. Click this link for more information.
ASME Sec. VIII Div.3


ASME HPS-2003: High Pressure System. This standard complements ASME SECTION VIII of the Boiler and Pressure Vessel Code as well as ASME B31.3-2002 Process Piping. Click this link for more information.
ASME HPS-2003