The discharge capacity for one fixture unit in a drainage pipe is?

The discharge capacity for one fixture unit in a drainage pipe is defined as 7.5 gallons per minute (gpm). This value is established by plumbing codes and guidelines to ensure proper drainage and to account for the expected flow of wastewater from a single fixture.

Understanding fixture units is essential in plumbing design, as they are used to calculate the total drainage load on a system. Each fixture, such as a sink, toilet, or shower, has a different demand for water, and these demands are converted into fixture units to assess the overall capacity required for drain lines. With the standard rate of 7.5 gpm for each fixture unit, engineers and plumbers can effectively design drainage systems that will handle the peak loads without risk of overflow or blockage.

The other provided answers (15 gpm, 30 gpm, 50 gpm) represent higher discharge rates that would apply if multiple fixture units were being considered or if specific types of plumbing fixtures required greater capacities. However, for a single fixture unit, 7.5 gpm is the established standard, making it the correct answer for this context.