What type of plumbing fittings allows for a change in direction of pipe flow?

The correct answer, which is elbows, is specifically designed to allow for a change in direction of pipe flow. Elbows are essential fittings in plumbing systems because they enable pipes to bend at specific angles, typically at 45 or 90 degrees. This flexibility is necessary for routing pipes around obstacles or directing flow towards different systems or areas, optimizing the configuration of plumbing installations.

Tees, although they also change the direction of flow, serve a different primary function—they create a branch in the piping system, allowing flow to split into two different directions instead of just bending the flow path. Couplings are used to connect two segments of pipe in a straight line and do not provide any directional change. Adapters, on the other hand, are fittings designed to connect pipes of different sizes or types rather than redirect the flow.