What is the term used for the percentage of fixture units active in a drainage system?

The term used for the percentage of fixture units active in a drainage system is commonly referred to as the Load Factor. This concept is crucial in plumbing design as it helps in assessing the actual demand on an drainage system based on the expected or potential use of various fixtures.

Load Factor essentially represents the ratio of the actual peak flow to the maximum flow rate that the system is designed to handle, allowing plumbers and engineers to design systems that are both efficient and effective while preventing overloading. A correct understanding of the Load Factor ensures that the drainage system operates safely under varying conditions of usage, thus improving reliability and preventing issues like backflow or blockages.

The other terms such as Flow Rate, Drainage Index, and Utilization Rate are not specifically measuring the percentage of active fixture units in the same way the Load Factor does, which underscores the relevance of Load Factor in plumbing code applications.