This guide is intended to cover such piping systems as low pressure heating, air-conditioning, refrigeration, and water supply, as well as some gas and chemical systems. These procedures include detailed welding process techniques that may be useful for teaching welders. Processes included are Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), Gas Tungsten Arc Welding (GTAW), Gas Shielded Flux Cored Arc Welding (FCAW-G) Flux Cored Arc Welding—Self-Shielded (FCAW-S), and Oxyfuel Welding (OFW). Qualification of these procedures to any welding standard is the responsibility of the user. This document does not address the needs of pipe steels or service conditions which may require post weld heat treatment (PWHT).

This standard makes use of both the International System of Units (SI) and U.S. Customary Units. The measurements may not be exact equivalents; therefore, each system must be used independently of the other without combining in any way. The standard with the designation D10.12:2000M uses SI Units. The standard designation D10.12M:2000 uses U.S Customary Units. The latter are shown within brackets ( ) or in appropriate columns in tables and figures. Pipe sizes are listed as DN (diameter nominal) and NPS (nominal pipe size). The exact pipe diameters are in Table C1.