International Building Code Section 2405


International Building Code 2405.1

Scope. This section applies to the installation of glass
and other transparent, translucent or opaque glazing material
installed at a slope more than 15 degrees (0.26 rad) from the
vertical plane, including glazing materials in skylights, roofs
and sloped walls.

International Building Code 2405.2

Allowable glazing materials and limitations. Sloped
glazing shall be any of the following materials, subject to the
listed limitations.
1. For monolithic glazing systems, the glazing material of
the single light or layer shall be laminated glass with a
minimum 30-mil (0.76 mm) polyvinyl butyral (or equivalent)
interlayer, wired glass, light-transmitting plastic
materials meeting the requirements of Section 2607,
heat-strengthened glass or fully tempered glass.
2. For multiple-layer glazing systems, each light or layer
shall consist of any of the glazing materials specified in
Item 1 above.
Annealed glass is permitted to be used as specified within
Exceptions 2 and 3 of Section 2405.3.
For additional requirements for plastic skylights, see Section
2610. Glass-block construction shall conform to the requirements
of Section 2101.2.5.

International Building Code 2405.3

Screening. 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
mmby 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 (1.5m2) 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.

International Building Code 2405.4

Framing. In Type I and II construction, sloped glazing
and skylight frames shall be constructed of noncombustible
materials. In structures where acid fumes deleterious to metal
are incidental to the use of the buildings, approved pressure-
treated wood or other approved noncorrosive materials
are permitted to be used for sash and frames. Framing supporting
sloped glazing and skylights shall be designed to resist the
tributary roof loads in Chapter 16. Skylights set at an angle of
less than 45 degrees (0.79 rad) from the horizontal plane shall
be mounted at least 4 inches (102 mm) above the plane of the
roof on a curb constructed as required for the frame. Skylights
shall not be installed in the plane of the roof where the roof
pitch is less than 45 degrees (0.79 rad) from the horizontal.
Exception: Installation of a skylight without a curb shall be
permitted on roofs with a minimum slope of 14 degrees
(three units vertical in 12 units horizontal) in Group R-3
occupancies. All unit skylights installed in a roof with a
pitch flatter than 14 degrees (0.25 rad) shall be mounted at
least 4 inches (102 mm) above the plane of the roof on a curb
constructed as required for the frame unless otherwise specified
in the manufacturer´┐Żs installation instructions.
2006 INTERNATIONAL BUILDING CODE.
GLASS AND GLAZING

International Building Code 2405.5

Unit skylights. Unit skylights shall be tested and
labeled as complying with AAMA/WDMA/CSA
101/I.S.2/A440. The label shall state the name of the manufacturer,
the approved labeling agency, the product designation
and the performance grade rating as specified in
AAMA/WDMA/CSA 101/I.S.2/A440. If the product manufacturer
has chosen to have the performance grade of the skylight
rated separately for positive and negative design pressure,
then the label shall state both performance grade ratings as
specified in AAMA/WDMA/CSA 101/I.S.2/A440 and the
skylight shall comply with Section 2405.5.2. If the skylight is
not rated separately for positive and negative pressure, then the
performance grade rating shown on the label shall be the performance
grade rating determined in accordance with
AAMA/WDMA/CSA 101/I.S.2/A440 for both positive and
negative design pressure and the skylight shall conform to Section
2405.5.1.

Unit skylights rated for the same performance
grade for both positive and negative design pressure.
The design of unit skylights shall be based on the following
equation:
(Equation 24-13)

Unit skylights rated for separate performance
grades for positive and negative design pressure. The
design of unit skylights rated for performance grade for both
positive and negative design pressures shall be based on the
following equations:
(Equation 24-14)
(Equation 24-15)

International Building Code 2405.5.1

Unit skylights rated for the same performance
grade for both positive and negative design pressure.
The design of unit skylights shall be based on the following
equation:
(Equation 24-13)

International Building Code 2405.5.2

Unit skylights rated for separate performance
grades for positive and negative design pressure. The
design of unit skylights rated for performance grade for both
positive and negative design pressures shall be based on the
following equations:
(Equation 24-14)
(Equation 24-15)