Which fitting is typically used to connect two pieces of plumbing at a 90-degree angle?

The fitting that is typically used to connect two pieces of plumbing at a 90-degree angle is the elbow fitting. Elbows are specifically designed to change the direction of piping, allowing for turns in the plumbing system, which is essential for navigating around obstacles or for directing water flow in the desired path.

Elbows come in various angles, with the most common being the 90-degree elbow, which ensures a tight turn in plumbing installations. This capability makes elbows fundamental in creating the necessary angles for an efficient and effective plumbing layout.

In contrast, couplings are used to join two straight sections of pipe, reducers are employed to connect pipes of different diameters, and unions enable the easy disconnection of pipe sections without cutting. While these fittings serve important functions in a plumbing system, they do not provide the directional change that elbows do.