Shurjoint Grooved Piping System

    The Shurjoint grooved piping system is one of the most advanced, versatile, economical and reliable systems available today.  After the pipe ends are grooved a gasket is stretched over the pipe ends. The coupling segments are then placed over the gasket and the bolts and nuts are fastened resulting in a secure and leak free joint.

    A coupling can be installed 3–4 times faster than a comparable welded or brazed joint and there is no need for a flame or welding torch on the job site.  A coupling can be installed by fastening a pair of bolts and nuts while using only a wrench or spanner, whereas a comparable flanged joint requires the fastening of many bolts and nuts with a pair of wrenches. The grooved system allows for easy material take-offs and unlike a threaded system, there is no need to allow for added pipe length for thread engagement. With the removal of just a few bolts one can easily access the system for cleaning, maintenance, changes and or system expansion.

Major Pipe Joining Methods - Quick Comparison

RIGID OR FLEXIBLE?

Shurjoint grooved couplings are classified into two types, flexible and rigid. What are the differences? When and where should they be used? The following information is intended for system designers and installers to better understand the nature of the grooved piping systems. This will allow the designer and installer to make better use of the design features and advantages of grooved piping advantages of grooved piping components and systems.

Note:1) Angular movement of flexible couplings 8" and larger sizes should be ≧ 0.5°

         2) Axial displacement data based on roll-grooved pipe

Rigid Couplings

The most popular and most widely used couplings today

Shurjoint rigid couplings can be used in applications where you require a rigid joint similar to that of a traditional flanged, welded and or threaded connection. You need not worry about the snaking of the pipe on straight runs, as all Shurjoint rigid couplings utilize both a mechanical and frictional interlock design to provide rigidity. Rigid couplings eliminate or reduce undesired angular movement, axial displacement and rotation after installation as is required under normal service conditions. Rigid couplings are some of the most popular and most widely used today.

Shurjoint offers three different types of rigid couplings, the angle-pad design, the T&G (tongue and groove) design and the most recent innovation, the butt-joint design. The butt-joint design effectively eliminates the gap between pipe ends, offering increased rigidity.

#R20 Butt-joint Rigid Coupling

​Angle-pad design: As the bolts are tightened, the angled bolt pads slide in opposite directions causing the couplings keys to tightly grip the pipe, while at the  same time the pipe grooves are forced outward against the coupling keys.

T&G design: The T&G (tongue & groove) mechanism provides a mechanical and frictional interlock resulting in a rigid joint which reduces undesired angular movement. Shurjoint precision casting techniques allow the coupling segments to meet metal-to-metal when installed on properly grooved pipe.

Butt-joint design: The unique butt-joint design eliminates the gap in between pipe ends, thus eliminating not only angular and rotational movement but also axial displacement under normal service conditions*. Fluid will not directly contact the gasket nor sit in the gasket pocket. The coupling segments will always come together forming metal-to-metal contact when properly installed. (*Pipes must be cut true and square to achieve a butt-joint.)

Flexible Couplings

Shurjoint flexible couplings allow for full design features in such applications as curved or deflected layouts and or when systems are exposed to outside forces beyond normal static conditions such as seismic events or where vibration and or noise attenuation are a concern. The ability to design in controlled flexibility is an advantageous feature when compared to traditional rigid joining methods such as threading, flanging and welding. When designing with flexible couplings you must allow for proper support to the system so as to eliminate undesired stress (see Anchoring, hanging and supports on data sheet #B-20).

There are several published standards and codes covering grooved piping components. These codes or standards may vary as to the definition or standard for flexible couplings. System designers should confirm which standard(s) and or code(s) are required for the system being designed and they should select the applicable coupling for the application. The NFPA 13 defines a flexible coupling as;

"a listed coupling or fitting that allows axial displacement, rotation, and at least 1 degree of angular movement of the pipe without inducing harm on the pipe. For pipe diameters of 8 in. and larger, the angular movement shall be permitted to be less than 1 degree but not less than 0.5 degrees.” (NFPA 13- 2007 3.5.4)

For sprinkler systems, NFPA 13 specifies the use of flexible couplings to protect the system against damage from earthquakes and sets some specific examples of how and where they should be used. Designers and installers should design their fire protection systems in compliance with this standard. See Typical Applications of Flexible Couplings on Shurjoint Data Sheet #B-19.

Axial Displacement & Angular Movement (Models 7705 & 7707)  

Note: † Allowable Axial Displacement and Angular Movement (deflection) figures are for roll grooved standard steel pipe.  Values for cut grooved pipe will be double that of roll grooved.  These values are maximums; for design and installation purposes these figures should be reduced by: 50% for ¾” – 3½”; 25% for 4” and larger to compensate for jobsite conditions.

** Deflection or angular movement is the maximum value that a coupling allows under no internal pressure.