The intake opening which draws air from the outside atmosphere shall be located at a point that prevents contamination of the air supply and shall be unobstructed at all times. The intake opening shall be located not less than 15 feet from the discharge outlet of any exhaust fan, plumbing vent and chimney or similar object. Unless adequate means are provided to remove dust from the air, the bottom of the intake opening shall be not less than 10 feet above the surface of any abutting public way, gangway, driveway, grade, or abutting roof. No intake opening shall be placed in a horizontal position in any sidewalk, or in the pavement of any street, alley, or driveway, or within 12 inches of the level of any other surrounding grade; nor shall any intake opening take air from the lower level of any two-level street or similar construction. In loading docks, intake openings shall be located not less than 10 feet horizontally or vertically from any loading dock door.
Exceptions:
1. Interior loading spaces and appurtenant driveways. No ventilation openings for loading spaces and appurtenant driveways shall be required if the following conditions are met:
1.1 Loading spaces and appurtenant driveways are used in manufacturing, storage or mercantile units;
1.2 Doors open directly to the outside atmosphere at each loading space;
1.3 The loading dock is raised at least 36 inches above the adjacent driveway;
1.4 The doors are situated no more than 65 feet from the dock; and
1.5 The dock area is separated from the interior of the unit by a wall or door or by both.
2. No ventilation openings for exterior loading spaces and appurtenant driveways shall be required if the following conditions are met:
2.1 The loading dock is constructed with the floor of the dock not less than 36 inches above the adjacent driveway; and
2.2 The driveway is not enclosed; and
2.3 At least 20 percent of the lineal footage of the total external wall of the dock or 50 percent of the lineal footage of the largest external wall of the dock consists of loading doors.