What is code for gre piping?

The code for gas piping in the United States is primarily governed by the National Fuel Gas Code (NFPA 54) and the International Fuel Gas Code (IFGC). For GRE (Glass Reinforced Epoxy) piping specifically, industry standards such as ASTM D2996 and ASME B31.3 may apply, depending on the application and region. It's essential to consult local regulations and codes, as they can vary significantly. Always ensure compliance with the latest safety and installation standards.