Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 24 - Glass and Glazing
Section 2404 - WIND, SNOW, SEISMIC AND DEAD LOADS ON GLASS
Subsection 2404.2 - Sloped glass

Glass sloped more than 15 degrees (0.26 rad) from vertical in skylights, sunrooms, sloped roofs and other exterior applications shall be designed to resist the most critical of the following combinations of loads.

where:

D = Glass dead load psf (kN/m2).

For glass sloped 30 degrees (0.52 rad) or less from horizontal,

= 13 tg (For SI: 0.0245 tg).

For glass sloped more than 30 degrees (0.52 rad) from horizontal,

= 13 tg cos [THETA] (For SI: 0.0245 tgcos [THETA]).

Fg = Total load, psf (kN/m2) on glass.

S = Snow load, psf (kN/m2) as determined in Section 1608.

tg = Total glass thickness, inches (mm) of glass panes and plies.

Wi = Inward wind force, psf (kN/m2) as calculated in Section 1609.

Wo= Outward wind force, psf (kN/m2) as calculated in Section 1609.

[THETA] = Angle of slope from horizontal.

Exception: Unit skylights shall be designed in accordance with Section 2405.5.

The design of sloped glazing shall be based on the following equation:

where:

Fg = Total load on the glass determined from the load combinations above.

Fga = Short duration load resistance of the glass as determined according to ASTM E 1300 for Equations 24-2 and 24-3; or the long duration load resistance of the glass as determined according to ASTM E 1300 for Equation 24-4.