daren12
Mechanical
- Jul 2, 2021
- 3
Hi all quick question.
We have a pressure vessel which falls under alteration. Long story short we hydro tested it to ASME code UG-99(b)and not NBIC Part 3, 4.4.2(1)(a).
I am trying to interpret the paragraph 4.4.2(1)(a) which states: "A pressure test as required by the original code of construction shall be conducted. The test pressure shall not exceed 150% of the MAWP stamped on the pressure retaining item, as adjusted for temperature. When the original test pressure included consideration of corrosion allowance, the test pressure may be further adjusted based on the remaining corrosion allowance".
The original vessel was designed to Sec VIII Div 1.
My first question is: can the first sentence of 4.4.2(1)(a) be interpreted as a hydrostatic test pressure per UG-99(b) shall be conducted (original code of construction) or does it mean following the same testing method as outlined in Sec VIII Div 1 for the hydro test.
My second question is: on my nameplate I have a MAWP of 150psig @ 650F. The second sentence of 4.4.2(1)(a) says the test pressure shall not exceed 150% of MAWP stamped on the pressure retaining item, as adjusted for temperature. The "as adjusted for temperature" is not very clear to me. Could this be interpreted as MAWP x 1.5 x LSR = Maximum hydro test pressure? Or is it just MAWP which is stamped on the nameplate of the vessel multiplied by 150% and ignore the 650F?
Any help or direction would be appreciated.
Thanks
Daren
We have a pressure vessel which falls under alteration. Long story short we hydro tested it to ASME code UG-99(b)and not NBIC Part 3, 4.4.2(1)(a).
I am trying to interpret the paragraph 4.4.2(1)(a) which states: "A pressure test as required by the original code of construction shall be conducted. The test pressure shall not exceed 150% of the MAWP stamped on the pressure retaining item, as adjusted for temperature. When the original test pressure included consideration of corrosion allowance, the test pressure may be further adjusted based on the remaining corrosion allowance".
The original vessel was designed to Sec VIII Div 1.
My first question is: can the first sentence of 4.4.2(1)(a) be interpreted as a hydrostatic test pressure per UG-99(b) shall be conducted (original code of construction) or does it mean following the same testing method as outlined in Sec VIII Div 1 for the hydro test.
My second question is: on my nameplate I have a MAWP of 150psig @ 650F. The second sentence of 4.4.2(1)(a) says the test pressure shall not exceed 150% of MAWP stamped on the pressure retaining item, as adjusted for temperature. The "as adjusted for temperature" is not very clear to me. Could this be interpreted as MAWP x 1.5 x LSR = Maximum hydro test pressure? Or is it just MAWP which is stamped on the nameplate of the vessel multiplied by 150% and ignore the 650F?
Any help or direction would be appreciated.
Thanks
Daren
