"Product transfer pipe connected to bulk tanks should be installed and tested to meet the requirements of National Fire Protection Association 30, 'Flammable and Combustible Liquids Code'. The design, fabrication, assembly, test and inspection of piping systems should be suitable for the working pressures and structural stresses for which they will be used. Piping systems should be liquid tight and connected by joints that are welded, flanged, threaded or mechanically attached. The pipe in the illustration is welded and flanged."
Coffee Break Training - Fire Protection Series No. FP-2013-27
United States Fire Administration: http://www.usfa.fema.gov/