ASME VIII Div 1 2019 and temperature limit of steel cast valves

[engrom]

Does the recent version (2019) of ASME VIII Div 1 change the minimum temperature of carbon steel cast valves A216 WCB, WCC from -30deg C to -8deg C. One of the US pressure relief valve supplier is stating that the code has changed so that the body / bonnet material of new valves with a design envelope less than -8C will have to be low temperature carbon steel (LCC) material. Previously these valve bodies were good for upto -29 degC.

I would appreciate any confirmed info as none of the other relief valve vendors or industry forums have highlighted this issue or does the summary of changes in ASME VIII highlight this.

 

[bcd]

Steel valve design and materials are per ASME B16.34. The low temperature limits for WCB, etc. specified in B16.34 are still the same. That is -29 C (-20 F). Material stress criteria for determining wall thickness and pressure/temperature ratings for valves in B16.34 is more conservative than the BPVC. Could be the reason why valves have not changed the low temperature ratings.

 

[TGS4]

In all of these conditions, the minimum temperatures are without impact testing. The B16 codes do not address minimum temperatures, but they are required by the construction codes (Pressure Vessel Code or Piping Code).

These changes have been noted by many.