Glass Standards for Wind and Snow Load
Many architects choose glass for its sleek, modern look in their building designs. While industry boasts of the strength in both steel and concrete, glass continues to gain popularity in modern construction designs. Any building material must be designed to stand up to the forces of nature. At Modern Glass, we pay special attention to the standards for the stress loads.
The American Society for Testing and Materials International (ASTM) develops and publishes technical standards for materials, products, systems, and services used all around the world. These standards protect consumers every time they buy a toy to every time they enter a hospital. Architects and other design professionals use the ASTM E1300 standards for glass in their designs.
ASTM E1300 lays out the method for evaluating glass load resistance. For years, industry standards focused on the thickness of the glass for improved strength. As industry evolves, new technologies emerge that increase the strength of glass. Some of these technologies include laminated, insulated glass constructions and annealed or heat-treated glass. When an architect or designer creates glass for a project, they follow the procedures set for in ASTM E1300 to determine if the glass meets the requirements of the job. These ASTM procedures address issues including:
- Center-of-glass deflection. Glass can bow in our out, or move from its original position from external forces such as wind and snow load as well as changes in temperature. This change is called deflection.
- Different constructions of glass. Different possible constructions include monolithic, laminated and insulating glass made with annealed or heat-treated glass.
- Load durations. A short duration load (60 seconds) addresses forces such as a gust of wind. A long duration load (30 days) addresses forces such as snow load.
- The number of glass edges supported. Though most designs include support for all four sides, some designs support only one, two or three sides.
When designed using these procedures, and cared for and installed properly, the glass will handle and withstand the wind and snow loads placed upon them.
Designing the Glass for Wind and Snow Load
Depending on the use, size and location of the glass, designers use these ASTM standards to design the proper piece of glass for their project. Designers consider the following key concepts in their design:
- The Anticipated Design Load—the design load is measured in kilopascals (kPa) or Pounds per Square Foot (PSF). The design load is defined by local building codes.
- The Glass Type Factor—this factor is determined based on the type of glass used in the project compared with its short and long duration load capabilities.
- The Load Share Factor—when two lites (pieces of glass) with equal or different thickness are combined to create one piece of glass, they each have their own load capacity. This factor measures the combined load sharing between the two lites.
- Glass Strength—determined by its thickness, width, height and number of supporting edges.
- Resulting Load Resistance—the uniform load that the glass can sustain without breaking.
Modern Glass has been a trusted installer for over 70 years. We take pride in our quality of work and incorporate these considerations into our work, and we collaborate with many of the area’s leading designers and architects. By understanding the processes that design professionals follow, you can have confidence that your dream project will weather any storm.