Pressure-containing piece of equipment having end connections of different nominal sizes and/or pressure ratings, used to connect other pieces of equipment of different nominal sizes and/or pressure ratings

Alloy / Carbon Steel

Alloy of carbon and iron containing a maximum of 2% carbon (mass fraction), 1.65% manganese (mass fraction), and residual quantities of other elements, except those intentionally added in specific quantities for deoxidation (usually silicon and/or aluminium)

Bean Holder

A "Bean Holder" is commonly know as a "Cage Nipple" found in a positive choke.

Blank / Blind / Solid

A solid bean/seat is used to plug a choke valve.


Any portion of wellhead and christmas tree equipment between end connections, with or without internal parts, which contains well-bore pressure


Pressure-containing closure for a body, other than an end or outlet connection


Also referred to as a 2" Max Masterbean or a 2" Max Bean/Seat Adapter.  These are commonly used to reduce a 2" Max to 1" Max or to an OCT bean.  If you need to reduce the flow in a 2" Max but don't want to replace the entire choke, a cost effective solution is to use a "Bushing".


Equipment used to restrict and control the flow of fluids

According to the API Specification 6 section 10:

10.9 Chokes

10.9.1 General Positive and adjustable chokes are chokes which include restrictions or orifices to control the flowrate of fluids. Chokes are not intended to be used as shutoff valves.

a) Adjustable chokes Adjustable chokes have an externally controlled variable-area orifice coupled with an orifice-area-indicating mechanism as shown in Figure 20. Actuators for adjustable chokes are covered under 10.16.

b) Positive chokes Positive chokes accommodate replaceable parts having fixed orifice dimensions, which are commonly called flow beans.

Choke Bean / Flow Bean

Replaceable orifice part used in positive chokes to control flowrate

Choke Trim

Pressure-controlling choke component, including choke beans, used to control or regulate the flow of fluids

NOTE One-piece stems, and that segment of multi-piece stems that passes through the pressure boundary, are pressurecontaining components

Christmas Tree

Assembly of equipment, including tubing head adapters, valves, tees, crosses, top connectors and chokes attached to the uppermost connection of the tubing head, used to control well production


Protruding rim with holes to accept bolts and having a sealing mechanism used to join pressure-containing equipment, with dimensions specified in this International Standard


A "Needle" is a another name for an adjustable choke "Stem".


A plug is another name for a "Blanking Cap".

Pressure-Boundary Penetration

Device which penetrates directly into or communicates with the wellbore and is not defined elsewhere in this International Standard

EXAMPLES Grease or sealant injection fitting; check valve; control, test or gauge port plug and fitting, needle valve on test, gauge or injection port; electric and control line penetration.

Pressure-Containing Part

Part whose failure to function as intended would result in a release of retained fluid to the atmosphere

EXAMPLES Bodies, bonnets and stems.

Pressure-Controlling Part

Part intended to control or regulate the movement of pressurized fluids

EXAMPLES Valve bore sealing mechanisms, choke trim and hangers.

Retainer Ring

Often, the term "retainer ring" includes several rings: a physical retainer ring, snap ring, spirolox ring and a packing reatainer.  Also referred to as "Ret Rings".

Stainless Steel

Steel containing more than 11 % chromium (mass fraction) to render the steel corrosion-resistant

NOTE Other elements may be added to secure special properties.

Stuffin Box

A "Stuffin Box" is another name for a "Bonnet".


Pressure-containing fitting with three openings

NOTE Two openings opposite one another form the run portion of the tee, and one opening is at 90° to the line of the run. Tees may be equipped with threads, flanges, studs or other end connectors.

Thread Protector

Cap or insert used to protect threads and seals during handling, transportation and storage. Additionally, at Global Energy Products, a "Thread Protector" is a bean that has been drilled out to 64/64".  Often, it is used when a choke is fully open (the bean has been removed) to protect threads from getting "washed out" or damaged from abrasives.

Threaded Flange

Flange having a sealing face on one side and a female thread on the other for the purpose of joining flanged connections to threaded connections