Publisher Summary This chapter presents an outline of standards in the field of welded fabrication. The word “standard,” as it is commonly used in engineering, is a contraction of standard specification. It is a specification for a material or manufactured product that may be written by companies for internal use and by national and international bodies for public use. The word “standard” also refers to standard procedures, such as examinations and tests of materials and personnel. Standards have a number of purposes. At a simple level, their use minimizes the cost of production and maintenance of engineering products through the reduction in variety and the resulting interchangeability of similar parts. A purpose of a standard is to describe a product that has a specific level of performance. Standards should be used only as a support for good engineering and not as its basis. Standards are derived jointly by the parties interested in making and using the product, as well as by others and the time taken to prepare and publish a standard means that it cannot be based on the most up-to-date technology. In the field of welded fabrication, there are many standards describing the materials, the welding consumables, the welding plant, the management of welding operations, the inspection techniques and procedures, and the fabricated product itself. Naturally, many of these standards will be called up by manufacturers and customers in their product specifications, unfortunately, not always with adequate knowledge of their scope and content.