Guide to the Updated ASTM E1300-24

Design professionals use ASTM E1300 Standard Practice for Determining Load Resistance of Glass in Buildings to determine the glass thickness and type required to meet specified loads. The standard gives procedures to determine the uniform lateral loads perpendicular to the glass surface for monolithic, laminated and insulating glass. Charts are given for maximum lateral glass deflection.

ASTM E1300 is directly referenced in Chapter 24 of the International Building Code and indirectly referenced in Section R609 of the International Residential Code for design wind loads for exterior glazing not part of a labeled assembly.

Vertical and sloped glass in buildings are designed to resist wind and snow loads. Note that other factors outside the scope of ASTM E1300 are also relevant when selecting appropriate glass thickness for a given application, such as thermal stress, effects of windborne debris, building movement, noise abatement and safety glazing requirements.

What changed in the 2024 update?

ASTM E1300 technical adviser Stephen Morse, an associate teaching professor at Michigan Tech University, presented updates to the standard at the NGA Glass Conference: Isle of Palms | Charleston in February. The technical changes include adding material properties, analytical procedure corrections, glass bite pullout method, expanded approximate maximum allowable stress procedure and a revised effective thickness example, along with several editorial changes.

Glass Material Properties

Material properties were not previously included in ASTM E1300. The updated version now includes modulus of elasticity, Poisson ratio, density, surface parameters and static fatigue constant for soda lime glass. As other glass types are introduced in the standard, the corresponding material property values will be added.

Glass Bite Pullout Method

The standard says that the glass edges shall not lose support. It provides a method to estimate how much edge pull-in will occur based on the center of glass deflection. The straightforward equation addresses 2-, 3- and 4-side supported glass. The equation also recognizes changes that will be needed due to the types of edge support and the framing system.

Maximum Allowable Stress

The maximum allowable stress procedure is heavily modified in the new version of ASTM E1300. New tables were added with a series of allowable stresses based on time (three seconds to one year), heat treatment (annealed, heat-strengthened or fully tempered) and probability of breakage (8 in 1,000 or 1 in 1,000) to give designers a variety of options.

Revised Effective Thickness Method

The annex of the standard included an example calculation of effective thickness using a symmetric laminated glass construction. This was replaced in the updated version by an asymmetric laminated glass example with two sides simply supported. The calculation is unchanged, and values are provided for all intermediate calculation steps to improve the usability of the calculation.

Ongoing work of the committee

The ASTM E1300 Committee continues to work on expanding the non-factored load charts for larger glass dimensions and different aspect ratios. Non-factored load is defined as the three-second duration uniform load associated with a probability of breakage less than or equal to 0.008 for monolithic annealed glass. For laminated glass, all charts are being revised to account for current published shear modulus data from interlayer manufacturers, various interlayer thicknesses and constructions. Further updates to ASTM E1300 and other standards will continue to follow the industry-consensus ballot method.

How to access the standard

The updated standard is available to purchase and download from ASTM at astm.org/e1300-24.html. The National Glass Association collaborated with ASTM to co-publish ASTM Glass and Glazing Standards for the Building Industry. The compilation of 96 key ASTM standards includes forced-entry-resistant systems, flat glass, glazing, building sealants, acoustics and fenestration products. 

Get involved in standards development

Join NGA task groups

Your voice is needed to ensure standards reflect the interests of the industry. Consider volunteering your time to help shape technical resources. Specifically for glass and fenestration guidelines, NGA members may join NGA committees and task groups. These peer groups offer opportunities to discuss specific issues with other industry experts through virtual and in-person meetings, and to draft and refine guidelines via industry consensus that may be expanded and presented to ASTM for consideration as a new standard. To get involved at NGA, visit glass.org/membership.
 

Join ASTM

Several membership levels are available at astm.org/get-involved/membership, with opportunities to serve on technical committees.