Wing unions & swivels

Wing Unions - Hammer unions

Wing unions - Hammer unions are one of the most common "quick connection" methods used in the oilfield for joining together components in a temporary pipe work system. They also have expanding applications in fixed installations and also for industrial purposes.


* Fig. 100 & 400 also available with butt weld ends in some diameters. Consult Factory.
** Material: A350 LF2
BSP Threaded ends also available for some Figures. Consult Factory.
Material Certificates not available for Figures 50 to 206 with NPT Threaded ends.
PED 2014/68/EU compliance not available on the complete range. Consult Factory.


→ Wing unions Datasheet


FCE primarily manufactures wing unions for Sour Gas Service in Oilfield usage (particularly Well Testing) and special industrial applications.

Male & Female subs:Wing Unions 1

They are the pressure containing parts of the assembly that provide metal-to-metal primary seal. 

Subs are manufactured per different assembly modes:

  • Butt weld assembly
  • NPT threaded assembly
  • NPST threaded assembly
  • Sub profiles are also machined / forged as an integral part of a piping element.


This is a forged part of assembly that allows connection of the two subs through a specific Acme or Iso thread.

Seal Element:

Seal element is an elastomer component which acts as a secondary seal to protect metal-to-metal seal against corrosion. Depending on the union figure it can be a lip type ”Seal Ring” or an ”O-Ring”.
Different materials are available to suit fluid service (Buna for Standard service or FKM for H2S service).


NPST (Non Pressure Seal Thread)3604-NPST-EN

The NPST assembly is a special design for Higher Pressure service which can replace welded or conventionally Threaded union construction.

In this instance it can be seen from the illustration that the threads are not exposed to well effluent which is the case with conventional threaded (ie L.P.) components.

This type of construction, on straight flowline and pup joints, is generally more economically priced when compared to integral equipment.




Avoid the DANGER for interconnecting 2" Fig 602 and Fig 1002 with 2" Fig 1502.

Positively identify figure numbers and pressure ratings before connecting together 2 union halves.

Never strike, tighten, loosen or attempt repairs on pressurised components or connections.
Always apply essential care, handling and inspection to threaded components before, during and after make-up.
Never use severely worn, eroded or corroded components.
Never strike wing unions nuts having severely flattened and extruded ears.
Always use a bronze hammer in order to avoid sparkling while striking onto a wing union nut.


→ Download our well testing alert brochure

 wing unions-hammer unions







PLUGS & TEST PLUGSwing unions-hammer unions 3

Male and female hammer union plugs are available in all figures and all sizes. When ported, plugs can be used for different purposes (pressure testing, end of line drainage or venting). Port is generally 1/2" NPT but can be threaded to client requirement.


GROOVED NUTSwing unions-hammer unions (1)

Grooved nuts are generally used in industrial applications where assembly operation is more popularly done by the use of wrench rather than hammer.

Grooved nuts provide many advantages such as:

  • Fast tightening
  • Zero vibration, shock and deforming while tightening
  • Limited overall dimension for installation and storage

FCE offers grooved nuts for figure 602 in 2" and 3" as well as suitable "Key Fore" wrenches.


DRILLED HOLES NUTSwing unions-hammer unions (2)

FCE also offers drilled holes nuts for Figures 206 and 602 in 2", 3" and 4" diameters for industrial applications.

With suitable "Weco Rail" wrenches.