Underground commercial kitchen grease ducts must be encased in concrete with a minimum thickness of how many inches?

Underground commercial kitchen grease ducts are required to be encased in concrete to provide adequate fire protection and prevent grease-related fires from spreading. The minimum thickness for this concrete encasement is specifically set at 4 inches. This thickness is mandated to ensure that the encasement can sufficiently contain any potential fire and withstand the high temperatures generated by grease duct systems.

This requirement is designed in line with safety codes and regulations to enhance the structural integrity while also addressing concerns related to fire hazards inherent in commercial kitchen operations. Ensuring that the encasement is at least 4 inches thick strikes a balance between effective containment and practicality for installation within commercial settings.