What does "fixture unit" measure in plumbing?

A "fixture unit" is a key concept in plumbing that quantifies the probable demand for a water supply and drainage from a plumbing fixture. This measurement is essential for designing plumbing systems, as it allows plumbers and engineers to assess the expected flow and drainage requirements for a particular fixture under typical usage conditions.

The fixture unit system takes into account various factors such as the type of fixture, the frequency of use, and the peak demand periods, providing a reliable means to evaluate how much water each fixture will likely require. This approach helps in sizing pipes, selecting pumps, and ensuring that the plumbing system can effectively handle the expected load without overloading or underperforming.

By focusing on the probable demand rather than just the physical characteristics or quantity of fixtures, plumbing professionals can ensure that systems are both efficient and functional, leading to effective water management in residential and commercial buildings.