Units and ductwork in which at any point one horizontal dimension of the equipment on a roof is more than 4` but less than 8` shall have a clearance of at least _____ inches from the bottom of the duct to the finished roof. d roof.

Units and ductwork in which at any point one horizontal dimension of the equipment on a roof is more than 4` but less than 8` shall have a clearance of at least _____ inches from the bottom of the duct to the finished roof. d roof.