Glass Thickness

For purposes of this discussion, there are three basic types of glass: monolithic, laminated, and insulating. Complete definitions of each of these glass types are presented in a later section. The true thickness of monolithic glass is defined as the overall thickness of the plate. Its value can be found though the use of a micrometer, a reflective thickness gage, or an ultrasonic thickness device. Each of these instruments can provide reliable measurements for the purposes of the current discussions. It should be noted that the true thickness of glass as determined through direct measurement is usually slightly less than the nominal thickness of glass that is used for commercial identification of the glass. The following table presents the relationship between nominal glass thickness and the minimum true thickness of glass for glass thickness of interest. For example a piece of glass with a true thickness of 0.223 in. (5.66 mm) should be referred to as 1/4 in. (6.0 mm) glass. 

Glass Thickness Table (need to be replaced by the pdf document Glass Thickness Table I sent you 6-10-11)

Nominal Thickness IN/MM  Minimum Thickness IN/MM)  Nominal Thickness IN/MM  Minimum Thickness IN/MM 
3/32 (2.5)  0.085 (2.16) 1/4 (6.0)  0.219 (5.56)
7/64 (2.7)  0.102 (2.59) 5/16 (8.0)  0.292 (7.42)
1/8 (3.0)  0.115 (2.92) 3/8 (10.0)  0.355 (9.02)
5/32 (4.0)  0.149 (3.78) 1/2 (12.0)  0.469 (11.91)
3/16 (5.0)  0.180 (4.57) 3/4 (19.0)  0.719 (18.26)

                 

The thickness of an IG unit is defined as the individual thickness of the monolithic glass plates that make up the IG unit. Thus if an IG unit is constructed using two pieces of 1/8 in. (3.0 mm) monolithic glass, its thickness should be recorded as 1/8 in. (3.0 mm). 

The nominal thickness of a laminated glass unit is found by doubling the nominal thickness of the glass plates that are incorporated into the laminated glass unit. Thus, if a laminated glass unit is constructed using two pieces of 1/8 in. (3.0 mm) monolithic glass, the glass thickness of the laminated glass unit should be recorded as 1/4 in. (6.0 mm). It should be noted that an ultrasonic thickness measurement made on a piece of laminated glass will provide the thickness of only one of the layers of the glass that is incorporated in the unit. A micrometer or optical measurement will provide the total thickness of the laminated glass plate (thickness of both glass plates plus the interlayer thickness). 

As a general rule: The use of solar control film is not recommended for clear annealed glass if the thickness of the glass exceeds 3/8 in. (10.0 mm). The use of solar control film is not recommended for tinted annealed glass if the thickness of the glass exceeds 1/4 in. (6.0 mm). The use of solar control film is not recommended for clear or tinted annealed laminated glass of any thickness. 

*Check your film manufacturer's guidelines for specific recommendations regarding these special glass types.


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