Which joint is associated with a rubber O-ring as a common seal element?

• A. Rubber O-ring
• B. Gasket Joint
• C. Solvent Weld
• D. Threaded

Answer: (B)

Rubber O-rings are a common seal element used in gasket-type joints. An O-ring sits in a groove or between mating surfaces and is compressed when the joint is assembled, allowing the elastomer to deform slightly and fill any gaps to prevent fluid leaks. This is the typical setup for a gasket joint, where the gasket (often rubber) provides the sealing surface between the connected parts.

The other joint types don’t center on an O-ring as the seal: a solvent weld relies on chemical fusion of plastic surfaces rather than a compressive seal from an O-ring, and threaded joints use threads and friction to seal rather than a ring-shaped gasket. A rubber O-ring itself isn’t a joint type; it’s the seal element used within gasket-type joints.