What is the maximum number of fixtures allowed on a 2-inch horizontal drain?

The maximum number of fixtures allowed on a 2-inch horizontal drain is based on the plumbing code and fixture unit calculations, which help determine the capacity of drainage systems. According to plumbing standards, a 2-inch drain line can handle up to 12 fixture units. Fixture units are a measurement that accounts for the potential flow and demand on a drainage system, allowing for better system design and ensuring that pipes can handle the expected load without issues such as clogging or backups.

Understanding fixture units is essential in plumbing design, as it allows for appropriate sizing of pipes to accommodate various types of fixtures, such as sinks, toilets, and bathtubs. A 2-inch drain optimized for 12 fixture units indicates that it can efficiently manage the waste from multiple standard fixtures, ensuring proper drainage and system performance under typical usage scenarios.

The incorrect options suggest a lower capacity (8 or 10 fixture units) or a higher capacity (14 fixture units) for the 2-inch horizontal drain, which does not align with established plumbing codes that provide guidelines for drainage systems.