What is the unit equivalent of a plumbing fixture that has a 1-1/2" trap?

A plumbing fixture with a 1-1/2" trap is considered to have a unit equivalent of 1 unit. This is based on plumbing codes and standards that categorize different fixtures according to their drainage capacity measured by the size of their traps.

In residential plumbing, a 1-1/2" trap is typically used for common fixtures like sinks, lavatories, and floor drains. Each type of fixture is assigned a drainage unit value based on its trap size; in this case, fixtures with a 1-1/2" trap are uniformly designated as 1 unit.

Understanding these unit equivalents is crucial for plumbing contractors when calculating the total drainage load for a building. It allows for accurate sizing of drainage systems and ensures compliance with local codes, helping to prevent issues like sewer backup or inadequate drainage. Other trap sizes, such as 2" or larger, would correspond to higher unit values, but are not relevant in this specific context where only a 1-1/2" trap is being considered.