Oldcastle BuildingEnvelope® can calculate the most suitable glass for use in any given application. However, it is the responsibility of the design professional to calculate and provide the equivalent design load. This calculation must take into account the correct combination of snow load (if applicable), wind load and dead load. Without the equivalent design load, Oldcastle BuildingEnvelope® must rely on the conservative limits recommended by the American Architectural Manufacturers Association (AAMA) for four-side uniform support. See AAMA Guidelines below
|AAMA Guidelines for Overhead Glazing|
|Designation in inches||Glass Type||Outboard Lite in inches||Air Space in inches||Inboard Construction
Glass-PVB-Glass in inches
|1/4||Annealed||–||–||1/8 - 0.030 - 1/8||12||3.42|
|3/8||Annealed||–||–||3/16 - 0.030 - 3/16||18||5.05|
|1/2||Annealed||–||–||1/4 - 0.030 - 1/4||24||6.67|
|5/16||Heat-strengthened||–||–||1/8 - 0.060 - 1/8||25||3.58|
|7/16||Heat-strengthened||–||–||3/16 - 0.060 - 3/16||40||5.21|
|9/16(1)||Heat-strengthened||–||–||1/4 - 0.060 - 1/4||40||6.83|
|13/16(1)||Heat-strengthened||–||–||3/8 - 0.060 - 3/8||40||10.09|
|11/16(1)||Tempered||–||–||1/2 - 0.060 - 1/2||40||13.33|
|7/8||Annealed||1/8||1/2||1/8 - 0.030 - 1/8||12||5.05|
|11/16||Annealed||3/16||1/2||3/16 - 0.030 - 3/16||18||6.67|
|11/4||Annealed||1/4||1/2||1/4 - 0.030 - 1/4||24||8.29|
|7/8||Heat-strengthened||1/8||1/2||1/8 - 0.060 - 1/8||25||5.21|
|11/8||Heat-strengthened||3/16||1/2||3/16 - 0.060 - 3/16||40||6.83|
|15/16||Heat-strengthened||1/4||1/2||1/4 - 0.060 - 1/4||40||8.45|
These are conservative designs assuming the glass is horizontal with maximum snow load.
Detailed engineering design particularly on sloped glazing can often increase the maximum allowable size.
(1) These products are recommended for point-supported canopies. Point supported laminates must be fully tempered.