What is the minimum height above the roof that Type L venting systems must terminate?

Type L venting systems must terminate a minimum of 2 feet above the highest point of the roof that is within a horizontal distance of 10 feet from the vent. This requirement is in place to prevent backdrafts and to ensure that combustion gases are safely vented away from the roofline and do not pose a risk of re-entering the building. The 2-foot height helps to ensure adequate dispersion of those gases into the atmosphere, minimizing the risk of carbon monoxide or other harmful gases accumulating near the building. Furthermore, this height requirement also accounts for potential snow accumulation and other environmental factors that may affect the vent’s performance.