§ 27-646 Thickness of glass.
AC § 27-646
Thicknesses of glass panels shall be chosen either on the basis of statistical probability of breakage (subdivision (a) of this section) or on the basis of table 10-7, at the designer's option.
(a)Statistical probability. Thickness of glass panels shall be chosen so that the statistical probability of breakage when the glass is initially subjected to the design wind load specified in table RS 9-5-1 does not exceed the values indicated in table 10-6. Probability or load factors used for design shall be derived by test. The sufficiency and validity of such test data shall be subject to approval by the commissioner.
(b)Alternate requirements. Alternative to the requirements of paragraph (a) above, the thickness of glass panels may be chosen from table 10-7. For glass with assured minimum thickness greater than required by reference standard RS 10-68, the maximum areas in table 10-7 may be increased in proportion to the assured minimum thickness. TABLE 10-6Probability of Breakage for Glass Panels (Based on Coefficient of Variation of 25%) Elevation Above Grade of Mid-Point of GlassArea of Panel – Sq. Ft.0-50-Ft 0-6060-8080-100100-120120+0-50 1.0%1.0%1.0%1.0%1.0%50 or more 1.0%0.8%0.6%0.4%0.2% TABLE 10-7Maximum Area of Glass – Sq. Ft. Nominal Thickness of Glass – InchesElevation Above Grade of Mid-Point of Glass – Ft.0-50 50-300300-600600+Sheet Glass Single strength 9 98 7Double strength 13 1311103/16" 25 2521197/32"32 322724Plate and Float Glass 13/64" 252521191/4" 37 3732285/16"54 5446403/8" 78 7463581/2" 114 10086755/8" 152120103903/4" 210 1371181037/8" 2411581351181" 312 204175153
