The highest fixture connected to a waste or soil stack that does not require a re-vent is referred to as what?

The term that describes the highest fixture connected to a waste or soil stack that does not require a re-vent is known as stack vented. In plumbing systems, when a fixture is installed at the highest point of a waste or soil stack, it is designed to allow for proper drainage without necessitating an additional vent. This is because the vertical venting provided by the stack itself is sufficient to prevent siphoning, maintaining the necessary air pressure within the drainage system.

Choosing "stack vented" captures this concept effectively. The fixture in this scenario relies on the existing stack for venting, simplifying the plumbing design and reducing installation complexity. Essentially, stack venting utilizes the natural rise of the stack to ensure that adequate air flow is maintained to facilitate drainage, which is crucial for the proper function of the plumbing system as a whole.

The other terms refer to different venting methods that are used in various plumbing configurations, which are not applicable when discussing the highest fixture connected to the waste or soil stack without needing a re-vent.