SRJ Snap Ring Joint

The weld-free Snap Ring Joint (SRJ) solves many of the problems commonly associated with welded and flanged joints in pipelines and process piping. It can be used in both new lay and established pipework, as a temporary or permanent solution.

SRJ Asymmetrical

  • SRJ-Techologies
    A range of simple, yet highly innovative connecting and repair solutions.
  • SRJ-Techologies
    A range of simple, yet highly innovative connecting and repair solutions.
  • SRJ-Techologies
    A range of simple, yet highly innovative connecting and repair solutions.
SRJ CouplingHover over image for cut away view.

SRJ Asymmetrical

  • SRJ non-weld connector that can allow for lateral movement of pipe section for ease of pipe extraction and maintenance

  • Overview
  • Operating Principle
  • Installation


Snap Ring Joint (SRJ) technology is a highly cost-effective alternative to conventional mechanical connector and to welded joints in many applications. It offers lower costs in each phase of the life cycle. Other benefits of the SRJ non-weld technology include:

  • Removes the risk of explosion due to hot-works in a hydrocarbon-rich environment.
  • Enables the use of advanced performance coatings due to the absence of welding.
  • Designed to have equal or more strength than the pipe in the line.
  • Capable of being removed and re-used if required.
  • Suitable for permanent or temporary applications.
  • It is lighter and therefore uses less raw material, and costs less to transport.
  • It is more space efficient and easier to install in tight areas.

The SRJ coupling has undergone a stringent test regime in order to gain Lloyds Register and ABS Type Approval for use in a variety of applications requiring high pressure fluid transmission; including shipping, Oil and Gas, utilities, chemicals, processing and desalination.

The SRJ is fully compliant with ASME B31.1, B31.3, B31.4, B31.8, B31.9 and IACS, as well as being approved by Lloyds Register as a permanent replacement for welded or flanged connections up to 16” N.B as standard.

Snap Ring Joint Limited are always looking to increase the scope of the technology by designing couplings for new applications.

Contact SRJ Limited to discuss your application.

Operating Principle

The SRJ comprises a single sleeve which houses the joint’s sealing and gripping elements and that spans the two pipe ends. The grip is provided by retaining wires located in grooves in the body and the corresponding grooves machined into the periphery of the pipe.

The Joint’s material can be selected to match a variety of commonly used piping materials. It is designed to meet the requirements of the mechanical specification of the pipe line, including the pressure rating.

The retaining wires are chosen per application. They are made of counter wound wires, made of a material to meet the applications specification, creating a flexible shaft. They include a termination fitting for ease of installation and removal with the use of the tool piece.

The sealing system comprises high integrity elastomeric seals - currently available in HNBR (Nitrile) or Viton - which are capable of sealing high pressures and against a range of pipeline media.

Each Joint is supplied with an outer environmental seal that minimises water access into the gap and in turn reduces the threat of corrosion. In addition, corrosion inhibitor grease is injected into the annular gap to provide extra protection to the retaining wires and groove faces.

Each coupling is specifically designed to the customer’s application. Each Joint also has the option of including integrity ports for post installation testing, which includes two extra seals and four ports.


The connector is supplied with:

  • Pre-Fitted Inner Seals
  • Environmental Seal
  • Retaining Wires with Tool
  • Corrosion Inhibitor
  • Outer Coating
  • Integrity ports (Dependant on application)
  • Hydraulic Fitting Tool (Dependant on application)

A conventional onsite clamshell cutting machine is used to cut and prepare the pipe grooves, bevel and finish under the seal area.

An installation tool is supplied along with the coupling for larger pipe. Hydraulic rams are used to bring the piping together before the retaining wires are inserted.



Operating Principle and Key Features


To install the connector (supplied pre-fitted with radial seals), the pipe ends are cut and prepared with the use of a conventional clamshell cutting machine. This machine, fitted with form tools, is used to machine the grooves required to locate the connector’s retaining wires in the pipe periphery.

If access is available at the pipe ends and one of the pipes can be moved longitudinally, then the SRJ connector would be installed onto one of the pipes to half its ength and the mating pipe is then pulled into the connector.

If however, the pipes cannot be pulled longitudinally, i.e. a spooled installation between two fixed ends, the connector would be completely assembled onto one of the pipes. This would leave its outer end flush with the pipe end. Then the mating pipe would be lowered into position and when the pipe ends are butted, then then the connector is centralised.

For larger OD connectors, a hydraulically-activated unit is used to position the connector on the pipe, thereby eliminating seal friction.

Alternatively, normal manual pipe handling equipment can be used. In all cases, once in position, the SRJ connector is locked in place by fitting the retaining wires. Typically, the overall length of the SRJconnector is equal to twice the pipe’s OD, so the actual access requirements are kept to a minimum, making its use ideal in tight access situations, such as the hook up phase of a project.


Nominal Pipe Diameter Pipe OD SRJ Diameter
114.3 mm
203.2 mm
219.075 mm
304.8 mm
323.85 mm


Benefits & Advantages



  • Cold work installation – eliminates the risk associated with Welding.
  • Reduces risk of fugitive emissions
Size / Weight
  • 40/50% more compact than a comparable flange. Closer pipe runs.
Speed of Installation
  • approx 3 hours per coupling with less skilled technicians.
Cost Reduction
  • Time savings 18/24 hours per connection compared to welded flange.


The SRJ offers many benefits over other pipe connection methods: –
  • Withstands high internal pressures and has equivalent mechanical strength of a weld
  • Eliminates costly welding workscopes by replacing coded welders with trained operatives
  • Speed of installation compared to welding workscope
  • Enhances safety on-site and ATEX requirements by eliminating the risks of welding
  • Does not compromise internal pipe coating, unlike welding
  • Avoids the need to weld difficult materials such as CuNi, Monel and Duplex
  • Potential for testing post-installation with the SRJ equipped with integrity ports
  • Lightweight and compact, cutting transport costs and enabling closer pipe rack design
  • Can be dismantled and reassembled

Installation Times vs. Welding

10” 900Lb
Pipe Cutting and Preparation
Pipe Alignment
Flange alignment and welding per flange
Pre Heat
Stress relieve
Coupling Installation
Connecting flanges / gaskets / bolts
Total Hours
SRJ Saving

Note – Pipe preparation times for SRJ and welding considered to be equal.

SRJ vs. ANSI Flanges

Nominal Pipe Diameter Pipe O/D
SRJ Diameter
ANSI 900 LB Dia
Nominal Pipe Diameter Pipe O/D
SRJ Weight
ANSI 900 LB Dia
35 lbs
125 lbs
175 lbs
415 lbs
480 lbs
767 lbs

Snap Ring Joint Limited, 9 The Esplanade, St.Helier, Jersey, JE2 3QA, UK.
tel: +44 (0) 1534 626 818
Snap Ring Joint Limited. All rights reserved