According to "Materials Selector for Hazardous Chemicals, Vol. 5: Nitric Acid" published by MTI, much of the piping used in nitric acid applications is 304L stainless steel. 304L is preferred over 304 to avoid sensitization. Crevice corrosion is common when using austenitic stainless steels for nitric acid service so threaded and socket welded connections should be avoided. Likewise, flanged joints should be minimized as much as possible. This leaves fusion welding as the preferred method of joining stainless steel pipe. Piping should be fabricated in accordance with ASME/ANSI B31.3 Code.