Purpose This specification is developed to provide for the safe and functionally interchangeable rotating control devices (RCDs) utilized in air drilling, drilling operations for oil and gas, and in geothermal drilling operations. Technical content provides requirements for design, performance, materials, tests and inspection, welding, marking, handling, storing, and shipping. This specification does not apply to field use or field-testing of RCDs. Critical components are those parts having requirements specified in this document. If product is supplied bearing the API Monogram and manufactured at a facility licensed by API, the requirements of Annex A apply.