A device used to determine the required number of toilets, sinks, showers, and other plumbing apparatus within a building is an essential tool in building design and construction. It relies on occupancy type and anticipated usage to ensure adequate plumbing facilities for building occupants. For instance, a restaurant will require a different quantity of toilets and sinks than an office building of the same size.
The correct calculation of necessary plumbing components avoids both undersupply, leading to potential health and safety issues due to insufficient facilities, and oversupply, resulting in unnecessary costs and wasted resources. Historically, these calculations were often performed manually using plumbing codes and tables, a process that was time-consuming and prone to errors. Modern calculation methods have been refined and standardized to improve accuracy and efficiency, incorporating factors such as occupancy load and usage patterns.