What is the maximum number of drainage fixture units that a 4-inch trap arm can handle?

A 4-inch trap arm is designed to handle a specific capacity of drainage fixture units based on plumbing codes and standards. According to these guidelines, a 4-inch trap arm can accommodate a drain load of up to 6 fixture units. This capacity is influenced by factors such as the diameter of the pipe and the corresponding flow rate it can support efficiently without causing issues like blockage or backups. The sizing is essential to ensure that the drainage system functions optimally and can handle waste effectively without risking overloading. Thus, the maximum number of drainage fixture units that a 4-inch trap arm can handle is indeed 6.