(D) Minor Repair Garages
(a) Ventilation Provided. The entire floor area shall be unclassified where there is mechanical ventilation providing a minimum of four air changes per hour or 0.3 m3/min/m2(1 cfm/ft2) of exchanged air for each square meter (foot) of floor area. Ventilation shall provide for air exchange across the entire floor area, and exhaust air shall be taken at a point within 0.3 m (12 in.) of the floor.
(b) Ventilation Not Provided. The floor area up to a level of 450 mm (18 in.) above any unventilated pit, belowgrade work area, or subfloor work area and extending a distance of 900 mm(3 ft) horizontally from the edge of any such pit, belowgrade work area, or subfloor work area, shall be classified as Class I, Division 2.
(a) Ventilation Provided. Where ventilation is provided to exhaust the pit area at a rate of not less than 0.3 m3/min/m2 (1 cfm/ft2) of floor area at all times that the building is occupied, or when vehicles are parked in or over this area and where exhaust air is taken from a point within 300 mm (12 in.) of the floor of the pit, belowgrade work area, or subfloor work area, the pit shall be unclassified. [30A:184.108.40.206. Table 8.3.1]
(b) Ventilation Not Provided. Where ventilation is not provided in accordance with 511.3(D)(3)(a), any pit or depression below floor level shall be a Class I, Division 2 location that extends up to the floor level.