What is the maximum length of an invented closet stand pipe?

The maximum length of an invented closet stand pipe is 20 inches. This specific measurement is established in the Massachusetts Plumbing Code to ensure proper drainage and venting for water closets. An invented closet standpipe serves as a crucial component that allows for the effective flow of waste and air from the toilet, which helps maintain the proper function and prevents issues like siphoning or backflow. Keeping the length at a maximum of 20 inches ensures that there is enough space for air to enter, thus preventing drain line stoppages and maintaining an efficient system.

Longer lengths would impede the performance of the plumbing system, leading to potential clogs or difficulties in the flow of wastewater. Therefore, the maximum length is specifically capped at 20 inches to uphold plumbing efficiency and safety standards, which are essential for proper sanitation and operation within the plumbing system.