§ 59. Ventilation for shafts. 1. There shall be provided in the roof directly over each stair, fire-stair, dumbwaiter, elevator or similar shaft which extends to or within one story of a roof, a ventilating metal skylight of the cross-sectional area of such shaft. Such skylight need not, however, exceed twenty square feet in area. Where an existing skylight is smaller than the dimensions or area prescribed in this subdivision, no structural change shall be required, but a ventilating metal skylight fitting the existing opening in the roof shall be sufficient. Every skylight shall be glazed with plain glass in the roof of such skylight and shall be equipped with metal screens over and under the skylight. In lieu of a skylight a window of the same area at the top story shall be accepted.

2. Whenever there is a flooring of solid construction at the top of any enclosed stair, fire-stair, elevator or similar shaft, openings shall be left near the top of such shaft for ventilation. Such openings shall provide at least two hundred eighty-eight square inches of unobstructed ventilation and shall communicate directly with the outer air, or be otherwise ventilated in accordance with the provisions of the local building code.

3. It shall be unlawful to discharge into any such shaft any inflammable or volatile gases, liquids or other thing or matter which would endanger life.