A combination of approved bends making changes in direction is known as what?

The correct answer is a combination of approved bends that changes direction, known as an offset. An offset typically refers to a series of bends that are designed to move a pipe or conduit from one elevation to another or to navigate around an obstruction. This is particularly important in plumbing, piping, and electrical work as it allows for a more efficient routing of materials while maintaining system integrity and functionality.

Offsets are used when space is constrained, and a straight run of pipe is not feasible. Each bend within an offset adheres to specific angles and dimensions that allow for a smooth transition, preventing sharp turns that could restrict flow or damage the material.

In contrast, the other choices represent different parts or types of fittings. An elbow is a specific type of fitting used to change the direction of a pipe by a set angle (often 90 or 45 degrees) but does not necessarily consist of multiple bends in a single run. A bend might refer to any curve in a material but does not emphasize the combination aspect or the functionality of changing elevation. A joint is simply where two sections of pipe or conduits are connected, and while it may be involved in a change of direction, it does not define the specific arrangement of bends characteristic of an offset.