We are supplying one process plant in new zealand. Plant is in hazardous area zone 1, gas group IIB. I want to know which piping code will be governing this plant piping? Everywhere we use ASME B31.3. Can we use it in New zealand? If yes then can somebody tell me that which new zealand government codes will be superseding this like PECPR & etc.
My second question is from which pressure & temperature the stress analysis of individual pipe line is compulsory in this process plant?

I will be much thankful if people reply to this thread. On net there is very less information available about new zealand codes.