Note: The redline document is a comparison of the original 2010 edition of Spec 6A to the 2004 edition, it is not inclusive of current addendas. This document specifies requirements and gives recommendations for the performance, dimensional and functional interchangeability, design, materials, testing, inspection, welding, marking, handling, storing, shipment, purchasing, repair and remanufacture of wellhead and christmas tree equipment for use in the petroleum and natural gas industries. This document does not apply to field use, field testing or field repair of wellhead and christmas tree equipment.

This document is applicable to the following specific equipment: wellhead equipment (casing head housings, casing head spools, tubing head spools, cross-over spools, multi-stage head housings and spools); connectors and fittings (cross-over connectors, tubing head adapters, top connectors, tees and crosses, fluid-sampling devices, adapter and spacer spools); casing and tubing hangers (mandrel hangers, slip hangers); valves and chokes (single valves, multiple valves, actuated valves, valves prepared for actuators, check valves, chokes, surface and underwater safety valves and actuators, back-pressure valves); loose connectors (weld neck connectors, blind connectors, threaded connectors, adapter and spacer connectors, bullplugs, valve-removal plugs); and other equipment (actuators, hubs, pressure boundary penetrations, ring gaskets, running and testing tools, wear bushings).

This document defines service conditions, in terms of pressure, temperature and material class for the well-bore constituents, and operating conditions. This International Standard establishes requirements for five product specification levels (PSL). These five PSL designations define different levels of technical quality requirements.

This edition of Spec 6A is the modified national adoption of ISO 10423:2009, Petroleum and natural gas industries-Drilling and production equipment-Wellhead and christmas tree equipment. This specification contains the API Monogram Annex as part of the U.S. national adoption.