Deconstruction of Laminate and Applied Film Layers

Deconstruction of Laminate and Applied Film Layers

Laminate Interlayer Data

Optics can accurately calculate the optical properties of laminates as long as the component layers with the following characteristics:

  • Interlayers are measured with transparent glass with a solar transmittance Tsol > 0.820 and Tvis > 0.890. This ensures that a “constructed” laminate in Optics5 will always have a similar or lower transmittance than the reference laminate which determines the interlayer properties
  • No glass layers have coatings next to interlayers (embedded coatings).
  • Substrate layers (the base glass to which the interlayers are applied) are measured separately from the interlayers. This is the responsibility of the manufacturer submitting data to the IGDB, as discussed below.

As discussed in the LBNL document which contains guidelines for submitting data to the IGDB (International Glazing Database: Data File Format, Version 1.4, April 2003), “an interlayer is an adhesive layer used to join components in a laminate. The optical properties of laminate layers cannot be measured directly. Instead they are calculated from the spectral properties of a ‘reference laminate’ which consists of the interlayer laminated between two glass layers of known optical properties. To submit data for an interlayer, both the spectral optical properties of the reference laminate, and the glass layers used in the reference laminate should be submitted.”


Figure 1. How Optics “deconstructs” measured data to obtain interlayer information.

This means that in order for an interlayer to be added to the Optics5 “Interlayer” type, and therefore used in making laminate constructions in Optics5, the spectral data for a “reference” laminate which contains that interlayer is submitted to the IGDB as follows:

Optics5 can do an accurate calculation for the interlayer properties from the reference laminate as long as the substrate glass layers have a high solar and visible transmittance, hence the requirement of Tsol > 0.820 and Tvis > 0.890. This ensures that laminates that are later created in Optics5 with this interlayer will almost always have a lower solar and visible transmittance then the reference laminate.

Applied Film Data

As discussed in the LBNL document which contains guidelines for submitting data to the IGDB (International Glazing Database: Data File Format, Version 1.4, April 2003), “an applied film glazing is an adhesive backed film applied to a Monolithic substrate.” If the measured data submitted to the IGDB includes the substrate information, Optics5 can apply the film to another substrate.

This means that in order for an applied film to be added to the Optics5 “Applied Film” type, and therefore used in making applied film glass layers in Optics5, the spectral data for the “reference” substrate to which that applied film was attached, is submitted to the IGDB as follows:

  • Applied films are measured with transparent glass with a solar transmittance greater than 0.820 (Tsol > 0.820) and a visible transmittance greater than 0.890 (Tvis > 0.890). Glass that meets this criteria includes 3mm clear glass, 3 mm low-iron glass, 6 mm low-iron glass. This ensures that an applied film layer in Optics5 will always have a similar or lower transmittance than the reference substrate which determines the applied film properties
  • Substrate layers (the base glass to which the applied films are applied) are measured separately, without the applied films attached, and submitted to the IGDB. This is the responsibility of the manufacturer submitting data to the IGDB, as discussed below.
How Optics “deconstructs ” measured data to obtain applied film information.
Figure 2. How Optics “deconstructs ” measured data to obtain applied film information.