In plumbing, what does "FU" stand for?

In plumbing, "FU" stands for Fixture Units. Fixture Units are a standardized measure used to quantify the load that various plumbing fixtures place on a drainage or plumbing system. This measurement helps in the design and sizing of drainage and venting systems by providing a way to assess the expected flow of wastewater and the demand on the plumbing infrastructure that different fixtures will create.

The use of Fixture Units allows plumbers and designers to calculate the required pipe sizes and system capacity based on the total anticipated demand from all plumbing fixtures in a particular area. This is crucial for ensuring that the system can handle peak usage demands without causing backflow or drainage issues, promoting the overall efficiency and reliability of the plumbing system.

Understanding Fixture Units is essential for complying with plumbing codes and ensuring that a plumbing system is safe, efficient, and adequately designed to handle the anticipated loads.