Section 2405

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

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.

Annealed glass is permitted to be used as specified in Exceptions 2 and 3 of Section 2405.3.

Laminated glass and plastic materials described in Items 1 and 2 shall not require the screening or height restrictions provided in Section 2405.3.

For additional requirements for plastic skylights, see Section 2610. Glass-block construction shall conform to the requirements of Section 2110.1.

Where used in monolithic glazing systems, annealed, heat-strengthened, fully tempered and wired glass shall have broken glass retention screens installed below the glazing material. The screens and their fastenings shall be: capable of supporting twice the weight of the glazing; firmly and substantially fastened to the framing members; and 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. Annealed, heat

24-6 2022 CALIFORNIA BUILDING CODE

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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. Unit skylights installed in a roof with a pitch flatter than 14 degrees (0.25 rad) shall be mounted not less than 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’s installation instructions.

Unit skylights and tubular daylighting devices shall be tested and labeled as complying with AAMA/WDMA/CSA 101/I.S./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. Where 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. Where 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.

2405.5.1 Skylights rated for the same performance grade for both positive and negative design pressure. The design of skylights shall be based on Equation 24-13.

Fg ≤ PG (Equation 24-13)

where:

Fg = Maximum load on the skylight determined from

Equations 24-2 through 24-4 in Section 2404.2. PG = Performance grade rating of the skylight.

2405.5.2 Skylights rated for separate performance grades for positive and negative design pressure. The design of skylights rated for performance grade for both positive and negative design pressures shall be based on Equations 24-14 and 24-15.

Fgi ≤ PGPos (Equation 24-14)

Fgo ≤ PGNeg (Equation 24-15)

where:

PGPos = Performance grade rating of the skylight under

positive design pressure; PGNeg = Performance grade rating of the skylight under

negative design pressure; and

Fgi and Fgo are determined in accordance with the following:

For 0.6 Wo ≥ D,

where:

GLASS AND GLAZING

Wo = Outward wind force, psf (kN/m ² ) due to basic

design wind speed, V, as calculated in Section 1609.

D = The dead weight of the glazing, psf (kN/m ² ) as

determined in Section 2404.2 for glass, or by the weight of the plastic, psf (kN/m ² ) for plastic glazing.

Fgi = Maximum load on the skylight determined from

Equations 24-3 and 24-4 in Section 2404.2.

Fgo = Maximum load on the skylight determined from

Equation 24-2.

For 0.6 Wo < D,

where:

Wo = The outward wind force, psf (kN/m ² ) due to basic

design wind speed, V, as calculated in Section 1609.

D = The dead weight of the glazing, psf (kN/m ² ) as

determined in Section 2404.2 for glass, or by the weight of the plastic for plastic glazing.

Fgi = Maximum load on the skylight determined from

Equations 24-2 through 24-4 in Section 2404.2.

Fgo = 0.