Finding a Common Language for Glass Lingo
A new digital tool from the NGA helps provide clarity and efficiency to build and decode glass nomenclature
By NGA Advocacy & Technical Team
If you're not well-versed in ordering glass for residential windows and doors, the strings of letters, numbers and symbols that compose a product code may seem intentionally cryptic. Even with the experience, the terminology varies by region and company.
A shared, common language for glass improves clarity and efficiency for the whole industry. For glass manufacturers and fabricators, a predictable structure for encoding glass makeups also is essential for ensuring consistency and compatibility across today's automated and computer-assisted process management systems.
Deciphering standard glass nomenclature codes
Like a universal translator, the National Glass Association offers a new, visual, interactive tool for everyone to build or decode glass nomenclature. This online resource aligns with NGA technical resources.
To decode: Input a valid glass nomenclature code to parse out the glass description and makeup in detail.
To build:
- Start with the glass layers' kind of glass type, thickness, material, and front and back surfaces.
- Specify interlayer materials and thicknesses, or include spacers between layers.
- Assign coatings or surface designations to the front or back of the layers.
- Review and generate the glass nomenclature code.
Key components to generating glass nomenclature codes
Kind is key
Letters designate the kind of glass type, based on strengthening as follows:
- AS for annealed glass — if no kind code is given, annealed is assumed
- CS for chemically strengthened
- FT for fully tempered
- HS for heat strengthened
Metric measurements rule
Use millimeters when specifying glass, interlayer and airspace thicknesses. As standard, the glass nomenclature code will use the numeral only, dropping the mm.
Material matters
Material type follows the glass kind and thickness. The uppercase letters are an abbreviation for the material type code. These appear in braces { }. As examples:
- {CL} for clear — if no material type is given, clear annealed glass is assumed
- {BG} for blue green
- {LI} for low iron
- {PC} for polycarbonate
Signify the surface
Each glass layer has two surfaces, which can have separate coatings, textures and other decorative elements. A character or lowercase letter before the glazing thickness indicates the outboard surface property. One after the thickness indicates the inboard surface property. Sample surface characters include:
- a for acid-etched
- r for mirrored
Call out the coatings
When using an 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.
List interlayers
The interlayers also are listed in the glass nomenclature code. These lowercase letters are an abbreviation of the film/sheet type or the liquid/cure type, such as:
- b for polyvinyl butyral (PVB)
- ip for ionomer
Each ply is defined, separated by commas and followed by a hyphen with the nominal interlayer thickness and code. If needed, glass plies are listed at the beginning. The more complex the glazing unit, the longer the series.
As a simple example: glass with 6 mm clear, fully tempered outboard surface with a 1.52 mm PVB interlayer and a 6 mm clear, fully tempered inboard surface would be written as 6FT,6FT-1.52b.
IG cavity considerations
For insulating glass (IG), the cavity thickness is stated in mm to one decimal point, followed by the gas code:
- Ar for argon
- Kr for krypton
- V for vacuum
A gas fill percentage may be indicated, and is allowed using the online tool's preview feature. For example, “Ar9010” indicates 90% argon fill, which is standard for many low-e coated residential IG units. If no gas code or fill percentage is given, air fill is assumed.
Brackets [ ] are used to indicate the insulating/spacing gap when generating the summary for an IG unit.
As a complex example: insulating/spaced glass with 5 mm clear, fully tempered, low-e coated outboard surface with a 0.25 mm vacuum cavity and a 5 mm clear, fully tempered inboard surface with an 8 mm 90% argon-filled cavity and a 3 mm fully tempered, low-e coated inboard surface would be written as 5*FT[0.25V]5FT[8Ar9010]*3FT **Low-E, Low-E #2.
More examples
Single glazing
| Detailed configuration | Summary nomenclature |
|---|---|
| 3 mm clear, annealed glass | 0.76 mm PVB interlayer | 3 mm clear, annealed glass | 3,3-0.76b |
| 5 mm gray, heat-strengthened glass | 1.52 mm PVB interlayer | 5 mm clear, annealed glass | 5HS{GY},5AN{CL}-1.52b |
| 5 mm clear, annealed glass | 1.52 mm ionomer interlayer | 5 mm clear, annealed glass | 5,5-1.52ip |
IG unit
| Detailed configuration | Summary nomenclature |
|---|---|
| 5 mm clear, fully tempered, low-e coated glass [9.5 mm cavity with argon gas fill] 5 mm clear, heat-strengthened glass | 1.52 mm PVB interlayer | 5 mm clear, heat-strengthened glass | 5FT*[9.5Ar]5HS,5HS-1.52b**Low-E |
Triple IG unit with two low-e coated lites
| Detailed configuration | Summary nomenclature |
|---|---|
| 2.5 mm clear, annealed, low-e coated glass [6.4 mm cavity with 90% argon gas fill] 3 mm clear, annealed glass [6.4 mm cavity with 90% argon gas fill] 2.5 mm clear, annealed, low-e coated glass | 2.5*[6.4Ar9010]3[6.4Ar9010]*2.5**#2 Low-E Type, #5 Low-E Type |
