This Code provides requirements for evaluating the suitability ofmaterials used in piping systems for piping that may be subject to brittle failure due to low-temperature service conditions. While low-temperature service is usually considered to be below ambient tem-perature, brittle failure can occur at temperatures above ambienttemperature for certain combinations ofmateri-als, thicknesses, and stress levels. The definition of“low-temperature service” as used in this Code, therefore,varies widely across the many applications for which piping systems are used. For a building service air line,low temperature may be 0°C (32°F), whereas for a cryo-genic piping system, it could easily be −185°C (−300°F). 1However, the principles used to evaluate the suitability of a piping system as related to service temperature by evaluating the toughness of the material can be applied across a wide temperature range, and this Code has been established to provide uniform guidance in this area. This Code may be invoked in whole or in part by various piping codes and/or specifications and is only mandatory when so invoked.
