Glass Specifications, Layers, and Nomenclature

The industry uses surface numbers to describe the order and orientation of the materials which make up glass compositions. All glass makeups have an exterior surface that is referred to as surface number one. If the glass will form part of the building’s exterior, surface number one will be exposed to the outside environment. Odd surface numbers are always oriented toward the exterior.

Every piece of glass must also have an inward facing surface. Inward facing surfaces are always described by an even number. For example surface number two is the inward facing surface of the exterior-most piece of glass.

Provided with this surface labeling convention, surfaces #1 and #2 belong to the same piece of glass. Surfaces #3 and #4 not only relate to the same piece of glass, but they inform us that this piece of glass is the second piece of glass in relation to the exterior. Surfaces #9 and #10 would therefore belong to a piece of glass which is the fifth piece of glass relative to the exterior.

The industry accepts some variation in the nomenclature used to describe interfaces between the layers of glass compositions. We prefer using a capital “X” to denote the interface between different layers because it is not likely to be interpreted as having a different meaning. This convention leads to glass compositions being described in the following manner.

Layer X Layer X Layer X Layer X Layer

What remains is to substitute the actual description of the layer materials with respect to each layer. Descriptions ideally identify each physical attribute and material type contained within the layer; however, attributes are often omitted. Attributes can be omitted where there is not a preference for any available option with respect to others.

Importantly, glass will not appear in adjacent layers. Interlayers and insulating spaces bond glass together to form glass compositions and must be interleaved between glass layers. Bonding layers also do not appear adjacent to other bonding layers, glass layers must be interleaved between them.

Glass layer types include glass, interlayers, and insulating spaces.

Monolithic glass refers to a single piece of glass material. Monolithic glass can have the following physical attributes which, by convention within Bid Unity, are normally described in the order they appear below.

  • Thickness
  • Color
  • The outboard surface can have texture or coatings. By convention we enclose the description of applied coatings within square brackets to distinguish this information from the color and heat treatment attributes.
  • The inboard surface can have texture or coatings. By convention we enclose the description of applied coatings within square brackets to distinguish this information from the color and heat treatment attributes.
  • Heat Treatment (Annealed, Heat Strengthened, or Tempered) Abbreviations include Ann., HS, TP, and Temp.

Laminated glass refers to at least two pieces of monolithic glass material which are bonded continuously across their opposing surfaces. The bonding material is referred to as the interlayer. Interlayer materials are normally plastics, several types are commonly used, and they have varying physical properties. Interlayers can have the following physical attributes which, by convention within Bid Unity, are normally described in the order they appear below.

  • Thickness
  • Material Type
  • Color

Insulated glass refers to at least two pieces of glass material which are bonded to each other continuously along their edges and which enclose a gas. The gas material can be air, argon, other types of gasses, or a blend of different gasses. The gas material is primarily responsible for reducing the flow of energy through the glass and different types of gasses can conduct energy at different rates. The bonding material is normally composed of a spacer and an adhesive. Spacers can be made from different materials, can have different thicknesses, and different physical properties including different thermal conductances. Many different adhesives can be used, they have different physical properties, and primarily determine the duration of manufacturer’s warranties against seal failure. Insulating spaces can have the following physical attributes which, by convention within Bid Unity, are normally described in the order they appear below.

  • Thickness
  • Spacer Material Color (If not specified any color is assumed to be acceptable)
  • Spacer Material Type (If not specified any material is assumed to be acceptable)
  • Gas Fill Type (If not specified this is assumed to be air)
  • Grid (If not specified it is assumed that no grid is to be provided)

Combining these conventions we can describe complex glass compositions such as the following example.

1/4" Clear [SB 70 #2] HS x 0.090" PVB x 1/4" Clear HS x 3/8" Stainless Steel Spacer x 1/4" Clear Tempered