ASTM E1300 24 glass load calculator

What GlassLoad.com checks under E1300 24

• Thicknesses offered: 2.0 mm (picture glass), 2.5, 3, 4, 5, 6, 8, 10, 12, 16, 19, 22 and 25 mm. The calculation uses the minimum thickness of each designation from Table 4, unless you enter a thickness override.
• Scope load limit: 315 psf, wind, snow and self weight combined. If the design load is higher, the result is still shown with a warning that it is outside the scope of the edition.
• Glass types and durations: annealed, heat strengthened and fully tempered glass, for a short duration load (3 seconds) or a long duration load (30 days).
• Deflection: the approximate center of glass deflection, read from the E1300 deflection chart of the nominal thickness, or from the equation in Appendix X1 where the chart gives no value. E1300 24 states three rules there: deflections larger than the glass thickness are rounded to the nearest millimeter, a caution applies below one third of the load resistance, and an aspect ratio above 5 is treated as 5.
• Probability of breakage: for annealed glass the report gives the probability of breakage at the design load, using the failure model written in Annex A2. It is information only. Pass or fail still compares the design load with the load resistance.

What differs from the other editions

• Against E1300 12a: E1300 24 adds the 2.0 mm picture glass designation. Its Annex A2 is a full probability of breakage model with an analytical procedure in the body of the standard, where 12a has no procedure. It writes the probability as a decimal such as 0.008, where earlier editions say 8 lites per 1000. It also changes some insulating glass tables, which GlassLoad.com does not cover yet.
• Against E1300 09a: the scope limit is 315 psf instead of 210 psf, 25 mm glass is offered, the deflection equation is in Appendix X1 instead of Appendix X2, and the three deflection rules above are printed.
• The list of glass the standard excludes is worded a little differently. E1300 24 says that acid etched glass counts as float glass when its thickness meets C1036.

For monolithic glass on four sides, the printed non factored load charts of the editions agree closely. GlassLoad.com therefore uses the same load calculation for all of them, and the edition changes the thicknesses, the scope limit, the appendix names and the warning wording.

25 mm glass

For 25 mm glass the printed chart gives a load about 6 percent lower than the value calculated from the Table 4 minimum thickness of 24.61 mm. GlassLoad.com lets you choose either, and the report says which one it used. The same chart appears in E1300 12a.

Run a check with E1300 24

Open the calculator and pick E1300 24 as the edition. See also the guides, how the calculation works, the questions and answers and the guide on how to calculate glass load resistance. The other edition pages are E1300 16, E1300 12a and E1300 09a. Results are to be verified by a qualified professional.

Worked examples

These are the worked examples printed in E1300 24 that GlassLoad.com can run. GlassLoad.com computed each one from the printed inputs. Every example has its own page with all the steps. All worked examples

• Example 1, A3.1: Non factored load of a 47.24 by 59.06 in, 1/4 in annealed plate
• Example 2, A3.2: Non factored load of a 50 by 60 in, 1/4 in annealed plate
• Example 3, A3.3: Double glazed unit, 1/4 in tempered over 5/16 in laminated
• Example 4, A3.4: Center of glass deflection, 37.99 by 75.98 in, 1/4 in
• Example 5, A3.5: Center of glass deflection, 60 by 180 in, 3/8 in
• Example 6, A3.6: Triple glazed unit, 1/8, 3/32 and 1/8 in annealed lites
• Example 9, X1.2.1: Deflection with a measured thickness, converted from SI
• Example 10, X1.2.7: Deflection with a measured thickness, inch pound units

Not available in GlassLoad.com

• Example 7, A3.7: Probability of breakage of a laminated insulating glass unit. Not available in GlassLoad.com.
• Example X9.1, X9.7: Appendix X9 effective thickness of a laminated beam, a simply supported laminated beam. Not available in GlassLoad.com.