What term describes the distance between a soil, waste, and vent stack and a fixture trap?

The term that describes the distance between a soil, waste, and vent stack and a fixture trap is "fixture branch." This term specifically refers to the piping that connects individual fixtures to the horizontal waste line, leading into the stack. A fixture branch serves to convey wastewater away from the fixture's trap and into the larger drainage system, ensuring proper flow and preventing backflow.

In plumbing, understanding the fixture branch is essential to maintaining the drainage and venting systems effectively. It allows for the proper configuration of plumbing systems, ensuring that fixtures are adequately serviced without issues related to air flow or drainage. By recognizing how the fixture branch operates within the overall plumbing system, plumbers can design and troubleshoot installations more effectively.

The other terms provided in the options refer to different aspects of plumbing. For example, a drain run typically refers to the horizontal portion of a drain pipe that directs wastewater towards the sewer or another discharge point. Piping gradient describes the slope of a pipe, which is critical for ensuring that gravity assists in wastewater drainage. Lastly, a service line usually pertains to the line that delivers water from the main supply to the building, which is distinct from the function of a fixture branch.