Order D18.1 from AWS. The following is an excerpt from AWS.

This document outlines welding standards for use in the manufacture and construction of dairy and food product processing plants. Compiled at the request of the 3A Sanitary Standards Committee, which develops sanitary design standards for dairy and food processing, packaging, and handling equipment and systems. Covers the requirements for gas tungsten arc welding GTAW of austenitic stainless steel tube and pipe at least inch 6 mm in diameter in the fabrication and construction of new sanitary hygienic processing systems. The specification list the required essential and nonessential variables for a written welding procedure qualification WPS, and acceptance criteria for procedure qualification for visual and mechanical testing of welds. ANSI Approved. ISBN 0-87171-587-2. Please see AWS D18.1/D18.1M:2009 for new revision

This is more likely to contain the type of information you are looking for. Most AWS standards are like "cookbooks for welding" whereas ASME codes are anything but.

Best regards - Al