How is an air gap defined in a drainage system?

An air gap in a drainage system is defined as the unobstructed distance from a waste outlet to a receptor, such as a sink or drain. This definition emphasizes the importance of maintaining a physical separation between the waste outlet and the receptor to prevent the backflow of contaminated water. An air gap acts as a critical barrier that ensures wastewater does not siphon back into the clean water supply, thus protecting public health and safety.

This method is often used as a passive backflow prevention measure in plumbing systems. An adequate air gap is essential for systems where there is potential for contamination, making it a crucial aspect of plumbing design and compliance with health codes.

Understanding this definition highlights the role that air gaps play in maintaining safe water systems and why they are preferred over other methods of backflow prevention when designing plumbing systems. Other options may discuss different aspects of the plumbing system, but they do not capture the specific and vital role of an air gap in preventing contamination.