Glass Nomenclature

Written descriptions of glass can often lead to misunderstandings due to vague or varied interpretations of the terms used. Different regions of the country and the world use different terminology, measurement systems and structure when defining a glass makeup; terms can even change over time.  

This excerpt from NGA Glass Technical Paper Glass Nomenclature aims to standardize descriptive language for glass, providing clear and concise definitions of glass compositions that can be universally understood, and ensuring glass descriptions are precise and accessible to facilitate communication and improve efficiency in the industry.  

Excerpted from NGA Glass Technical Paper Glass Nomenclature – Schema 1 (FB78-25), available for free download.
 

Definitions of Common Materials 

Inserts: layers of sheeting or materials, continuous or non-continuous, within an encapsulated system. 

Interlayer: a layer or multiple layers of material acting as an adhesive between lites of glass and/or plastic which add(s) additional performance to the finished product, for example, penetration resistance, glass or plastic shard retention, solar control, acoustic insulation, color, design, or combinations thereof.  

Laminate: an assembly consisting of two or more lites of glass and/or plastic that are bonded together by interlayer material.  

Lite: a panel or sheet of glass or a panel or sheet of laminated glass. 

Ply: an individual layer of glass or plastic in a laminate. 

Kind: a classification of flat glass based on strengthening. Kinds are annealed (AN), heat-strengthened (HS), fully tempered (FT), or chemically strengthened (CS). 

Metric v. Imperial 

Using metric units to specify glass, interlayer, and airspace thicknesses allows for rapid understanding and summation of overall thickness. To make a more comprehensive structure for defining glass makeups, metric measurements will be used. 

Glazing 

When defining a monolithic lite of glass, use the nominal thickness. For example, 6 represents 6-millimeter thick glass. To further define the glass kind, the thickness can be followed with a self-declared kind abbreviation or code: annealed (AN), heat-strengthened (HS), chemically-strengthened (CS), and fully tempered (FT). If no kind code is given, annealed is assumed. 

Examples: 

• 6FT = 6 millimeters fully-tempered 
• 2CS = 2 mm chemically-strengthened 
• 10 = 10 mm annealed 

Glazing Materials 

When defining the type of glazing material, the glazing definition is followed by the material type in {} brackets or braces. If no code is provided, the material is clear annealed glass. Standard material type codes are defined in Table 1. 

Surfaces 

Each glazing material has two surfaces: an outboard and an inboard surface. These surfaces can have coatings, surface textures, and other decorative elements. To specify the surface properties, a character is placed before the glazing thickness to indicate the outboard surface property or after the thickness to indicate the inboard surface. 

When using the asterisk (*) to indicate specific manufacturer coatings, the name of the coating is used at the end of the product code after a double asterisk (**). If multiple coatings are used, they are listed in order from outboard to inboard, separated by commas (see Table 2). 

Interlayers 

There are several types of interlayers used in laminates, including, but not limited to: Aliphatic Polyurethane, Cured Resin, Ethylene Vinyl Acetate (EVA), Ionomer, Polyvinyl Butyral (PVB), Thermal Cure Resin, and UV Cured Resin interlayers. The interlayer type would be as indicated in Table 3.  

Laminates 

When defining a laminated lite, use the same definition of monolithic lites for each ply. Each ply would be separated by a comma and then followed with the interlayer code: 6,6–0.76b. 

Laminated Glass 

Laminates are often called out by their overall nominal laminate thickness, such as 7/16-inch or 9/16-inch in the United States, or by a metric configuration of 6.76 millimeters or 8.76 mm, for example. In many cases, the nominal configuration needs to be defined per layer in order for the laminate to be built and installed properly. As such, the listing of each layer can become bulky, especially if both imperial and metric units are used.  

Building the summary configuration for a laminate is as follows: 

1. Nominal thickness glass 1 (outboard) (add type if desired) 

2. <comma> 

3. Nominal thickness glass 2 (inboard) (add type if desired) 

4. <hyphen> 

5. Nominal interlayer thickness (to two decimal places) 

6. Interlayer type designation (brand or color may be added) 

Examples: 

• 6FT,6FT-1.52b = 6 mm fully-tempered | 1.52mm PVB | 6 mm fully-tempered 
• 3,3-0.38ev = 3 mm annealed | 0.38 mm EVA | 3 mm annealed 

Complex Laminates 

To expand on this structure, adding additional lites, all glass plies are listed at the beginning. For example: 6,6,6. The interlayer is designated after the glass plies. If the interlayer is consistent throughout, it is only listed once. For example: 6,6,6-1.52b. If any interlayer is different than the others, they all must be listed in order separated by commas. 6,6,6-1.52b,2.29b. 

• 6,6,6-1.52b,2.29b = 6mm annealed | 1.52mm PVB | 6mm annealed | 2.29mm PVB | 6mm annealed