Cross Connection Practice Exam

How does an Approved Air Gap need to be measured compared to the pipe diameter?

1. Equal to the pipe diameter

2. Twice the pipe diameter

3. 1 inch more than the pipe diameter

4. No specific requirement

The correct answer is: Twice the pipe diameter

An Approved Air Gap is a crucial safeguard in plumbing systems that prevents backflow, which can potentially contaminate potable water supplies. To maintain its effectiveness as a protection measure, the air gap must be properly sized in relation to the pipe diameter. When the air gap is specified to be twice the pipe diameter, it ensures that there is sufficient vertical separation between the highest possible water level in the receiving vessel and the lowest point of the discharge pipe. This standard is based on the principle that a larger air gap creates a wider buffer zone against backpressure and potential siphoning conditions, thus enhancing the overall safety of the potable water system. This requirement is integral to backflow prevention strategies because it minimizes the risk of contaminants entering the water supply from undesirable sources. The use of twice the pipe diameter for the air gap measurement is a well-established guideline that is supported by plumbing codes and best practices in the industry, making it a reliable method for ensuring the integrity and safety of plumbing systems.