Why aren’t circuit venting methods accepted in every jurisdiction across the U.S.? Circuit venting is not an engineered design system, nor does it need an engineer’s approval. Circuit venting has been used as a common venting practice in plumbing systems since the 1920s. It is recognized in various plumbing codes throughout the U.S. and abroad.
Let us go back in time. It is 1982, and I am designing a large commercial plumbing project. The building is a large warehouse distribution center, with a grocery store and a car wash. The plans indicate 48 floor drains, eight water closets and six lavatories. After considering all of the different venting options — and instead of individually venting each fixture drain or using a combination waste and vent system for the floor drains — the designers choose circuit venting for the entire project. The rules using circuit venting for this project are as follows: