608.1.3 Location of air outlets.
MC § 608.1.3
The location of air outlets shall comply with the following requirements: 1. Air outlets shall be located at least 3 inches (76.2 mm) above the floor. Exception: Air outlets may be located less than 3 inches (76.2 mm) above the floor where provisions have been made to prevent dirt and dust accumulations from entering the system.
2.Where located less than 7 feet (2133.6 mm) above the floor, outlet openings shall be protected by a grille or screen having openings through which a 1/2-inch (12.7 mm) sphere cannot pass.
3.Grilles may be located in floors provided they are installed so that they may be removed for cleaning purposes and provided they are constructed as follows: 3.1 Grilles up to 3 square feet (0.2787 m 2 ) in gross area shall be designed to support a concentrated live load of 250 pounds (113.4 kg) on any 4 square inches (2580.6 mm 2 ) of surface. 3.2 Grilles over 3 square feet (0.2787 m 2 ) in gross area shall be designed to support the same loads as the floor in the area where used. 3.3 If located where they may be walked upon, the opening in grilles shall reject a 1/2-inch (12.7 mm) sphere.
