One fixture unit is equivalent to?

One fixture unit is a term used in plumbing design to quantify the load that a plumbing fixture places on a plumbing system. In many plumbing codes, one fixture unit is often equated to a specific flow rate or capacity that can be expected from a fixture.

The correct choice indicates that one fixture unit is equivalent to 1 cubic foot per minute (cu.ft./min). This measurement helps plumbing engineers and designers estimate the demand placed on the water supply and drainage systems. By using fixture units, they can create systems that ensure adequate performance and prevent issues such as low water pressure or drainage backups.

The other options refer to different flow rates, which may not align with the conventional designation of fixture units. By establishing a standard measurement like cubic feet per minute as equivalent to one fixture unit, it allows for uniformity in design and a better understanding of how multiple fixtures will interact within a plumbing system.