NBC-2015 loads for ASME VIII-1 vessel supports

[marty007]

Hello everyone,

Is anyone aware of industry guidance that discusses how to apply wind/seismic loads from the National Building Code of Canada (NBC) to the design of ASME VIII-1 pressure equipment?

The issue I'm dealing with centers around the different design basis of the two codes. NBC-2015 is a Limit States Design (LSD) code, whereas ASME VIII-1 is an Allowable Stress Design (ASD) code. If we directly apply NBC-2015 LSD based load combinations to ASME VIII-1 ASD formulas, the result would be overly conservative.

Codeware Compress addresses this issue by reducing the NBC-2015 seismic load (E) by a factor of 2/3. This aligns with the load case combinations of NBC-1995 (2003 printing), back when the NBC was an ASD code. The NBC changed to a LSD code in 2005, but there is no direction provided for how to deal with design basis discrepancies.

Any available references to industry guidance or publications would be very much appreciated.

Thank you!

 

[KevinNZ]

New Zealand has the same problem with no direct link between the national loading code for Buildings and ASME for vessel design. The pressure equipment engineering community produced a guide (PN19) that uses 0.8 factor for ADS. 0.7 is used for ASCE/ASME design.