This specification sets forth the classification of welded joints of carbon and low-alloy steels for use in the design and manufacture of machinery and equipment subjected to static and dynamic loading. This specification is not intended to dictate load determination, design assumptions, safety factors, or calculation methods. These are the responsibility of the design engineer. The intent of this document is to establish the effect of weld joint geometry, welding practices, and quality control on allowable stress levels. The specification also provides practices that can be used for qualification and examination of welded joints used in fabrication of machinery and equipment. It is not the intent of this specification to restrict the use of other proven methods and procedures which achieve acceptable results and which have been agreed to in writing by the Owner and Manufacturer.

This specification makes use of both U.S. Customary Units and the International System of Units (SI). The measurements may not be exact equivalents; therefore each system must be used independently of the other without combining in any way. The specification with the designation D14.4 uses U.S. Customary Units. The specification D14.4M uses SI Units. The latter are shown in appropriate columns in tables and figures or within brackets [ ] when used in the text. Detailed dimensions on figures are in inches. A separate tabular form that relates the U.S. Customary Units with SI Units may be used in tables and figures.

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, and applicable federal and state regulations. Some sources of safety and health information can be found in Annex C.