How high must subslab soil exhaust system ducts terminate above the roof?

The height at which subslab soil exhaust system ducts must terminate above the roof is established to ensure proper ventilation and to prevent the potential accumulation of hazardous gases. Terminating the ducts at this specific height, which is 6 inches above the roof, helps to maintain adequate airflow while reducing the risk of backdrafts, which can occur if ducts are placed too low and may lead to a return of gases into the living spaces.

Additionally, this height aligns with codes and regulations aimed at minimizing the impact of exhaust discharges on the building and its occupants. It ensures that any harmful gases are effectively carried away from the roof line and do not re-enter through other openings in the structure. Proper termination height is essential for maintaining efficient system performance and safeguarding health and safety.