A piping arrangement extending 33.9 above the highest downstream opening is known as what?

A piping arrangement that extends 33.9 feet above the highest downstream opening is referred to as a barometric loop. This design is used in water distribution systems to prevent backflow and ensure that the system remains operable even under varying pressure conditions. The height of the barometric loop creates a pressure differential that keeps water flowing in the desired direction while preventing contaminants from entering the clean water supply.

In a barometric loop, the elevation helps maintain a consistent pressure head, thereby allowing for effective drainage and preventing siphoning effects that could lead to contamination. This system is particularly important in areas where elevation changes occur throughout the piping layout, making it a critical component in water quality management and system design.

Other options present specific functions or devices that do not directly relate to creating a high point in the piping system that prevents backflow. For instance, a pressure relief valve is designed to release excess pressure but does not function as a height elevation mechanism, while a check valve allows flow in one direction but does not establish a height above the highest point in the system. An overflow system is related to managing excess water but does not serve the primary purpose of creating a protective elevation like a barometric loop does.