Hello,

ANSI / ASME B31.8, Gas Transmission and Distribution Piping Systems, is the appropriate Code for the design of buried gas transmission lines (you may want to review the B31.8 Introduction and paragraph 802 regarding scope). Regarding temperature, B31.8 explicitly excludes from its scope piping with metal temperatures above 450 degrees F or below -20 degrees F. No single piping Code section can provide "rules" for every application. It is often necessary to supplement the information in the Codes with established good engineering practice to provide for a safe piping system for the intended application.

The design of structural analysis software for piping must closely follow the requirements of the Codes and should never presume to interpret the Code’s intent. CAESAR II can only implement in its algorithm the literal requirements found in the current section of the applicable Code. You may write an inquiry to the B31.8 Code Committee and reference is made to B31.8, Appendix O, Preparation of Technical Inquiries to the ASME Code for Pressure Piping, B31.

Regards, John.