Section 1208. Skylights. —

1. All skylights shall be constructed with metal frames except those for Groups A and J Occupancies. Frames of skylights shall be designed to carry loads required for roofs. All skylights, the glass of which is set at an angle of less than 45 degrees from the horizontal, if located above the first storey, shall be set at least 100 millimeters above the roof. Curbs on which the skylights rest shall be constructed of incombustible materials except for Types 1 or 11 Construction.

2. Spacing between supports in one direction for flat wired glass in skylights shall not exceed 625 millimeters. Corrugated wired glass may have supports 1.50 meters apart in the direction of the corrugation. All glass in skylights shall be wired glass: Except, that skylights over vertical shafts extending through two or more storeys shall be glazed with plain glass as specified in this Code: Provided, that wire glass may be used in ventilation equal to not less than one-eight the cross-sectional area of the shaft but never less than 1.20 meters is provided at the top of such shaft. Any glass not wire glass shall be protected above and below with a screen constructed of wire not smaller than 2.5 millimeters in diameter with a mesh not larger than 25 millimeters. The screen shall be substantially supported below the glass.

3. Skylights installed for the use of photographers may be constructed of metal frames and plate glass without wire netting.

4. Ordinary glass may be used in the roof and skylights for greenhouses, Provided, That height of the greenhouses at the ridge does not exceed 6.00 meters above the grade. The use of wood in the frames of skylights will be permitted in greenhouses outside of highly restrictive Fire Zones if the height of the skylight does not exceed 6.00 meters above the grade, but in other cases metal frames and metal sash bars shall be used.

5. Glass used for the transmission of light, if placed in floors or sidewalks, shall be supported by metal or reinforced concrete frames, and such glass shall not be less than 12.5 millimeters in thickness. Any such glass over 100 square centimeters in area shall have wire mesh embedded in the same or shall be provided with a wire screen underneath as specified for skylights in this Code. All portions of the floor lights or sidewalk lights shall be of the same strength as required for floor is surrounded by a railing not less than 1.10 meters in height, in which case the construction shall be calculated for not less than roof loads.