"The scope of this document is multipass@ orbital machine pipe groove welding of pipe by arc fusion processes with filler metal addition. The orbital machines described in this document are typically used to weld pipe in plants@ such as power generation plants or chemical processing plants@ and to weld transmission pipelines@ both cross-country and offshore. Offshore pipeline construction includes ""S-lay@"" ""J-lay@"" and ""Reel-lay."" Each of these will be described in further detail. This guide is organized into sections describing welding processes@ pipe beveling@ pipe line-up@ weld heads@ nondestructive examination@ plant pipe welding@ cross-country welding@ ""S-lay"" welding@ ""J-lay"" welding@ and finally reel lay welding. The guide concludes with a brief description of methods used to estimate consumable usage@ engineering critical assessments@ methods to calculate maximum repair lengths@ and safety. This document excludes orbital tube welding@ which is addressed by AWS D18.1@ Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications. This document presents an overview of multipass orbital machine pipe groove welding including the welding processes@ pipe beveling equipment@ pipe line-up equipment@ welding equipment@ and nondestructive examination equipment. This document includes the steps required to prepare for and use multipass@ orbital machine pipe groove welding equipment. The alternative to multipass orbital machine pipe groove welding is manual welding@ which includes welding with a torch@ gun@ or electrode held and manipulated by hand. Orbital machine welding is a form of mechanized welding which offers an alternative to manual welding when the investment in mobilization and equipment costs can be offset by productivity gains. The goal of this guide is to familiarize the reader with the orbital machine alternative to manual welding. This standard makes use of both the International System of Units and U.S. Customary Units. The latter are shown within brackets ([ ]) or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore@ each system must be used independently. Safety and health issues and concerns are beyond the scope of this standard and therefore are not fully addressed herein. Safety and health information is available from other sources@ including@ but not limited to@ ANSI Z49.1@ Safety in Welding@ Cutting@ and Allied Processes@ AWS Safety and Health Fact Sheets (see Annex B) and applicable federal and state regulations."