MSS SP-155-2018 establishes requirements and criteria for factory-made plastic-lined metal valves intended primarily for conveying corrosive fluids. Preferred liner materials are listed in an accompanying table and do not include urethane and polyurethane liner materials. This Standard Practice applies to ball, check, plug, butterfly, and similar quarter-turn valves. It does not apply to diaphragm or plastic-lined knife gate valves. Requirements for materials, workmanship, dimensions, design, fabrication, working pressure and temperatures, test methods, qualification requirements, and markings are included within this Standard Practice.

This Standard Practice does not define the suitability of different liner materials to various chemical and operating environments and does not involve products coated with plastics.