What is the maximum fixture load on a 3" pipe?

The maximum fixture load on a 3" pipe is determined based on the plumbing code's specifications for the drainage system design. In the context of waste and vent systems, fixtures are assigned a Drainage Fixture Unit (DFU) value, which helps to calculate the capacity of the piping.

For a 3" pipe, the maximum allowable load is typically established to ensure that the pipe can handle the expected volume of wastewater and that it can maintain proper flow without causing backpressure or blockages. According to various plumbing codes, a 3" pipe supports a maximum fixture load of 27 fixture units. This indicates that the pipe can adequately accommodate the discharge from multiple fixtures simultaneously, providing efficient drainage and ensuring compliance with safety and plumbing standards.

The other values mentioned do not align with the standards for a 3" drain. Values such as 15, 35, and 40 fixture units exceed the capacity of a 3" pipe and would likely result in inadequate drainage performance or an increased risk of system failure. Thus, adhering to the maximum value of 27 fixture units is essential for effective plumbing design and operation.