This specification covers the requirements for welding of stainless steels and nickel alloys (as well as carbon steels and other metals for some applications) in sheet, plate, bar, and other forms for the fabrication and construction of new tanks, vessels, and other equipment in sanitary (hygienic) applications. The welding of pipe or tube to a tank, vessel or other piece of sanitary equipment, for use as a nozzle or other opening, is included in this specification. This specification excludes the welding of tube and pipe for the transportation of sanitary (hygienic) system products and cleaning or sanitizing solutions. Pipe and tube welding for sanitary (hygienic) systems is covered in AWS D18.1, Specification for Welding of Austenitic Stainless Steel Tube and Pipe Systems in Sanitary (Hygienic) Applications.

This specification is intended for new construction and may also be applied to maintenance and repair of equipment in sanitary (hygienic) applications. This specification does not address structural, pressure design nor corrosion aspects of components and systems. However requirements in this specification should be applied in conjunction with other governing requirements

Sanitary processing systems are intended to include those systems handling products for human and animal consumption, or for cleaning and sanitizing solutions used in these systems. Such products include, but are not limited to, dairy, meat, poultry, vegetable, beverage, personal care items (such as shampoo, soap, toothpaste, cosmetics), and other products consumed or used by humans and animals. This specification may be used, in whole or in part, for other applications where hygienic fabrication is desired.

This specification addresses welding qualification and visual examination requirements for as-welded surfaces as well as finished surfaces.