How far above the flood level rim must the air gap be for indirect waste piping?

The requirement for the air gap concerning indirect waste piping is based on providing adequate protection against backflow and contamination. The proper air gap distance must prevent any potential backflow from occurring that could allow contaminated water to reach potable water supplies.

In this context, the air gap must be twice the effective opening of the indirect waste piping. The effective opening refers to the size or diameter of the opening through which the wastewater exits. By setting the air gap at twice the effective opening, it ensures there is an ample distance to prevent siphoning or other backflow phenomena that could compromise health standards and safety.

Setting the air gap to this specified distance effectively creates a safer environment by minimizing the risk of contaminated water entering the clean water supply. This standard aligns with plumbing codes focusing on backflow prevention and public health safeguards.