ISO 13628-4:2010 provides specifications for subsea wellheads, mudline wellheads, drill-through mudline wellheads and both vertical and horizontal subsea trees. It specifies the associated tooling necessary to handle, test and install the equipment. It also specifies the areas of design, material, welding, quality control (including factory acceptance testing), marking, storing and shipping for both individual sub-assemblies (used to build complete subsea tree assemblies) and complete subsea tree assemblies.

The user is responsible for ensuring subsea equipment meets any additional requirements of governmental regulations for the country in which it is installed. This is outside the scope of ISO 13628-4:2010.

Where applicable, ISO 13628-4:2010 can also be used for equipment on satellite, cluster arrangements and multiple well template applications.

Equipment that is within the scope of ISO 13628-4:2010 is listed as follows:

1. subsea trees:
   • tree connectors and tubing hangers,
   • valves, valve blocks, and valve actuators,
   • chokes and choke actuators,
   • bleed, test and isolation valves,
   • TFL wye spool,
   • re-entry interface,
   • tree cap,
   • tree piping,
   • tree guide frames,
   • tree running tools,
   • tree cap running tools,
   • tree mounted flowline/umbilical connector,
   • tubing heads and tubing head connectors,
   • flowline bases and running/retrieval tools,
   • tree mounted controls interfaces (instrumentation, sensors, hydraulic tubing/piping and fittings, electrical controls cable and fittings);
2. subsea wellheads:
   • conductor housings,
   • wellhead housings,
   • casing hangers,
   • seal assemblies,
   • guidebases,
   • bore protectors and wear bushings,
   • corrosion caps;
3. mudline suspension systems:
   • wellheads,
   • running tools,
   • casing hangers,
   • casing hanger running tool,
   • tieback tools for subsea completion,
   • subsea completion adaptors for mudline wellheads,
   • tubing heads,
   • corrosion caps;
4. drill through mudline suspension systems:
   • conductor housings,
   • surface casing hangers,
   • wellhead housings,
   • casing hangers,
   • annulus seal assemblies,
   • bore protectors and wear bushings,
   • abandonment caps;
5. tubing hanger systems:
   • tubing hangers,
   • running tools;
6. miscellaneous equipment:

• • flanged end and outlet connections,
  • clamp hub-type connections,
  • threaded end and outlet connections,
  • other end connections,
  • studs and nuts,
  • ring joint gaskets,
  • guideline establishment equipment.

ISO 13628-4:2010 includes equipment definitions, an explanation of equipment use and function, an explanation of service conditions and product specification levels, and a description of critical components, i.e. those parts having requirements specified in ISO 13628-4:2010.

The following equipment is outside the scope of ISO 13628-4:2010:

• subsea wireline/coiled tubing BOPs;
• installation, workover, and production risers;
• subsea test trees (landing strings);
• control systems and control pods;
• platform tiebacks;
• primary protective structures;
• subsea process equipment;
• subsea manifolding and jumpers;
• subsea wellhead tools;
• repair and rework;
• multiple well template structures;
• mudline suspension high pressure risers;
• template piping;
• template interfaces.

ISO 13628-4:2010 is not applicable to the rework and repair of used equipment.