What component is used to join the grooved pipe system?

The correct answer is coupling collar, as it is specifically designed to connect two sections of grooved pipe together. In a grooved piping system, the ends of the pipe are grooved and fitted with a coupling collar that fits over the grooves. This provides a secure and leak-proof connection while also allowing for some flexibility and movement.

Coupling collars are essential for maintaining system integrity, particularly in applications where pipes may expand or contract due to temperature changes. They're also useful for easier assembly and disassembly of pipe sections, which is important during maintenance or when modifications to the piping layout are required.

While flanges, unions, and end caps each serve important roles in piping systems, they are not specifically utilized in grooved pipe systems. Flanges are typically used for bolted connections, unions for quick disconnections without cutting the pipe, and end caps to seal the open ends of a pipe. Each of these serves different purposes that do not align with the unique requirements of joining grooved pipes effectively.