When installing a hinged up-blast fan, what is the minimum distance the ductwork must be away from the roof surface?

For the installation of a hinged up-blast fan as per NFPA 96 standards, maintaining an adequate distance between the ductwork and the roof surface is critical for safety and functionality. A minimum distance of 18 inches is specified to ensure proper airflow and prevent potential fire hazards due to heat buildup. This space allows for adequate clearance, which aids in the dissipation of heat and reduces the risk of ignition of combustible materials that may be near the roof surface.

Additionally, this clearance is necessary for maintenance and inspection purposes, ensuring that no blockages or accumulation of debris can interfere with the operation of the fan and ventilation system. By adhering to this guideline, operators can promote safer cooking environments, adhere to best practices in fire prevention, and mitigate the risk of roof damage or fire spread due to overheating.