What is the minimum distance a gas vent must terminate above the roof level when located near a vertical wall?

The correct answer reflects the requirement that gas vents must terminate at least 2 feet above the roof level when they are located near a vertical wall. This requirement helps to ensure that exhaust gases are properly dispersed away from the building and reduce the risk of them re-entering structures, which can be particularly important in regard to health and safety.

In addition to preventing the backdraft of flue gases, this minimum termination height is intended to mitigate the impact of airflow patterns created by the vertical wall. A vertical wall can create turbulence, potentially leading to dangerous conditions if gases are not vented sufficiently high above it. Thus, maintaining this 2-foot clearance allows for adequate venting and proper functioning of the gas appliance, in line with safety codes and best practices.