Where used in monolithic glazing systems, heat-strengthened
glass and fully tempered glass shall have screens installed below the glazing
material. The screens and their fastenings shall:
(1) be capable of supporting twice the weight
of the glazing;
(2) be firmly and
substantially fastened to the framing members and
(3) be installed within 4 inches (102 mm) of
the glass. The screens shall be constructed of a noncombustible material not
thinner than No. 12 B&S gage (0.0808 inch) with mesh not larger than 1 inch
by 1 inch (25 mm by 25 mm). In a corrosive atmosphere, structurally equivalent
noncorrosive screen materials shall be used. Heat- strengthened glass, fully
tempered glass and wired glass, when used in multiple-layer glazing systems as
the bottom glass layer over the walking surface, shall be equipped with
screening that conforms to the requirements for monolithic glazing systems.
Exception: In monolithic and multiple-layer
sloped glazing systems, the following applies:
1. Fully tempered glass installed without
protective screens where glazed between intervening floors at a slope of 30
degrees (0.52 rad) or less from the vertical plane shall have the highest point
of the glass 10 feet (3048 mm) or less above the walking surface.
2. Screens are not required below any glazing
material, including annealed glass, where the walking surface below the glazing
material is permanently protected from the risk of falling glass or the area
below the glazing material is not a walking surface.
3. Any glazing material, including annealed
glass, is permitted to be installed without screens in the sloped glazing
systems of commercial or detached noncombustible greenhouses used exclusively
for growing plants and not open to the public, provided that the height of the
greenhouse at the ridge does not exceed 30 feet (9144 mm) above
grade.
4. Screens shall not be
required within individual
dwelling units in Groups R-2, R-3
and R-4 where fully tempered glass is used as single glazing or as both panes
in an insulating glass unit, and the following conditions are met:
4.1. Each pane of the glass is 16 square feet
(1.5 m2) or less in area.
4.2. The highest point of the glass is 12
feet (3658 mm) or less above any walking surface or other accessible
area.
4.3. The glass thickness is
3/16 inch (4.8 mm) or
less.
5. Screens shall
not be required for laminated glass with a 15-mil (0.38 mm) polyvinyl butyral
(or equivalent) interlayer used within individual
dwelling
units in Groups R-2, R-3 and R-4 within the following limits:
5.1. Each pane of glass is 16 square feet
(1.5 m2) or less in area.
5.2. The highest point of the glass is 12
feet (3658 mm) or less above a walking surface or other accessible
area.
