How high must a single-wall metal pipe extend above the highest point when passing through a roof of a building?

The requirement for a single-wall metal pipe to extend above the roof level is aimed at ensuring safety and proper ventilation for the exhaust system. A height of 2 feet above the highest point of the roof is considered adequate to allow for adequate dispersion of any exhaust gases and to minimize the risk of re-entry of those gases into the building. This standard helps to prevent backdrafts and ensures that the exhaust can escape freely, thereby maintaining a safe environment inside the structure.

On the other hand, while higher extensions might provide additional safety margins in certain situations, regulations commonly specify a minimum requirement of 2 feet in many jurisdictions, as this offers a balance between functionality and practicality.