UL/FM Grooved Fittings

A short guide to UL/FM Grooved Fittings

How a grooved joint works

A grooved joint has three parts: pipe ends with a groove cut or rolled into them, a rubber gasket, and a two part housing. The gasket seals the joint and the bolted housing locks into the grooves. No welding or threading is needed, so joints can be made quickly and without hot work, which helps in occupied buildings and plant rooms.

Rigid and flexible couplings

Rigid couplings hold the pipe straight and firm and are the usual choice for fire protection pipework. Flexible couplings allow a small amount of movement, so they are used where the pipe has to move, for example near vibrating equipment or at some building separations. Where flexible couplings are used, the design code may call for extra bracing, so the layout should be agreed with the system designer.

What to check before ordering

• The approval or listing covers the exact style and size you plan to use.
• The gasket grade suits the service. EPDM is the standard grade for water systems.
• The groove specification of the pipe matches the coupling.
• The rated working pressure is above the highest pressure the system will see.

Where grooved fittings are used

Grooved fittings are common in fire sprinkler and hydrant pipework, pump room connections, risers and any line where fast, clean assembly matters.

This is general information. The governing code, the project design and the local fire authority decide the exact requirements for your site.

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