What is the minimum vent height requirement for B-vent termination?

The minimum vent height requirement for B-vent termination being above the roof line ensures that the exhaust gases can disperse safely and effectively into the atmosphere without being obstructed. This placement helps to prevent any potential backdraft conditions that can occur if the vent is too low, which could lead to dangerous gases entering the living space. Additionally, having the vent above the roof line aids in minimizing the likelihood of recirculation of combustion products, thus supporting proper ventilation for gas appliances.

While considerations such as surrounding building heights and ground clearance are important for overall safety and functionality, the primary requirement specifically focuses on the vent being positioned above the roof line to ensure optimal performance and safety standards are met for gas venting systems.