RIGID OR FLEXIBLE? T&G design: The T&G (tongue & groove) mechanism provides a mechanical and frictional interlock resulting in
Lede grooved couplings are classified into two types, a rigid joint which reduces undesired angular movement.
flexible and rigid. What are the diﬀerences? When and Lede T&G design allow tiny gap between two coupling
where should they be used? The following information is segments aGer installed on grooved pipe. intended for system designers and installers to beter
understand the nature of the grooved piping systems. This will allow the designer and installer to make beter use of the design features and advantages of grooved piping components and systems.
Lede flexible couplings allow for full design features in applications such as curved or deflected layouts and or
RIGID COUPLINGS when systems are exposed to outside forces beyond The most popular and most widely used couplings normal static conditions such as seismic events or where today vibration and or noise atenuation are a concern. The ability to design in controlled flexibility is an advantageous feature
Lede rigid couplings can be used in applications where when compared to traditional rigid joining methods such as you require a rigid joint similar to that of a traditional threading, flanging and welding. When designing with
flanged, welded and or threaded connection. You need not flexible couplings you must allow for proper support to the worry about the snaking of the pipe on straight runs, as all system so as to eliminate undesired stress (see Anchoring,
Lede rigid couplings utilize both a mechanical and frictional hanging and supports on page 48).
interlock design to provide rigidity. Rigid couplings
eliminate or reduce undesired angular movement, axial There are several published standards and codes displacement and rotation aGer installation as is required covering grooved piping component. These codes or under normal service conditions. Rigid couplings are some standards may vary as to the definition or standard for
of the most popular and most widely used today. flexible couplings. System designers should confirm which
standard (s) and or code(s) are required for the system Lede oﬀers two diﬀerent types of rigid couplings, the being designed and they should select the applicable
angle-pad design, the T&G (tongue and groove) design. coupling for the application.
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.