What is the minimum distance required for a tub filler's air gap if the effective opening is 1 inch in diameter and not affected by the nearest side wall?

The minimum distance required for a tub filler's air gap is determined by local plumbing codes, which are based on preventing back siphonage and ensuring safe drainage. When the effective opening of a filler is 1 inch in diameter, the minimum distance for the air gap must be at least twice the diameter of that opening. This standard helps ensure that there is adequate space to prevent any potential contamination of the potable water supply.

In this case, with an effective opening of 1 inch in diameter, the minimum distance for the air gap would be calculated as 1 inch x 2, resulting in a requirement of at least 2 inches. This ensures that any possible backflow of water during a drain or a pressure loss scenario does not compromise the water supply, thus maintaining the safety and integrity of the plumbing system.