How much higher must Type L vents extend above the highest point where they pass through the roof?

Type L vents are used in venting systems to ensure proper draft and to prevent the escape of harmful gases into living spaces. According to the code, Type L vents must extend above the highest point of the roof where they penetrate to ensure that they are safely above any potential obstructions such as parapets, dormers, or other structures that may interfere with the venting process.

The correct requirement is that Type L vents must extend at least 2 feet above the highest point where they pass through the roof. This height helps to maintain adequate ventilation and to avoid any backdraft situations that could occur if the vent is too low, particularly during adverse weather conditions or during times of high wind.

This 2-foot requirement ensures not only compliance with safety codes but also optimizes the efficiency of the venting system by allowing for unobstructed airflow. Proper installation according to this height specification is essential for ensuring that exhaust gases are effectively channeled away from the building's roof area, preventing any potential health hazards or structural issues associated with improper venting.