What is the total fixture unit count for a 4" waste pipe?

The total fixture unit count for a 4" waste pipe being 172 fixture units aligns with standard plumbing codes and guidelines regarding capacity and sizing of drainage systems. Fixture units are a standardized way to quantify the probable demand on a plumbing system from various fixtures.

In plumbing, the capacity of drainage pipe is determined based on its diameter and the expected flow from fixtures connected to it. A 4" waste pipe is suitable for handling a substantial number of fixture units, typically around 172, which is the maximum recommended before considering the additional capacity that might be needed for peak flows in a commercial or residential setting. This number allows for the simultaneous use of multiple plumbing fixtures without risking backflow or drainage issues.

Other choices do not reflect the correct understanding of the drainage system’s capacity for a 4" pipe. The lower choices suggest insufficient capacity, while the higher option greatly exceeds typical maximums and does not conform to established plumbing guidelines for a pipe of that size. The 172 fixture unit count represents a widely accepted standard for what is realistic and manageable in a 4" waste pipe application.