About the IGDB

About the International Glazing Database (IGDB)

The IGDB is a collection of optical data for glazing products. Spectral transmittance and reflectance is measured in a spectrophotometer and contributed to the IGDB by the manufacturer of the glazing product subject to a careful review.

If your goal is to submit data, you can jump to the instructions, but if you are new to the process, first you may wish to skim the answers to FAQs immediately following. 

What are the relationships between LBNL, the NFRC and the IGDB?

LBNL maintains and publishes the IGDB. NFRC is by far the single most important user of the IGDB. The NFRC window rating system is powered by the LBNL Window5 program (see next section), which in turn relies on the IGDB for input data.  NFRC charges a fee to the data supplier for any data that is used in the rating system. Some of this NFRC revenue is used to support LBNL for the operation of collecting the data.

The U.S. Department of Energy (DOE) provides support for the optical laboratory, participation in standards activities and related research. This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, State and Community Programs of the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

NFRC does not charge a fee for data that is not intended to be used for NFRC rating purposes, but all data goes through the same review process! You may contact either LBNL  or NFRC  to begin the process and your data will end up in the same place. 

Is the IGDB a part of the LBNL Window5 or Optics5 program?

A very close relationship exists between the IGDB and LBNL computer programs like Window5.  In fact, the IGDB is part of the download package with Window5 or Window6.. Most of the experimental input data required by Window5/6 to calculate the energy performance indices (e.g., U-factor and g-factor) of a window comes from the IGDB. The most basic purpose of Window5/6 is to calculate the properties of combinations of simple glazing materials (e.g., double and triple glazing units), whose properties are drawn from the IGDB. Other programs, however, including those developed at LBNL and elsewhere can read data from the IGDB.

A common occurrence is a request for a password to open the IGDB file directly in MS Access. Such requests are seldom granted because the intention is to open the IGDB directly with Window5/6 or other approved program, so as to avoid spreading modified versions of the tested database. 

What types of materials are passed through the review process?

As of the date on this page, only specular glazing materials, however complex they may be in physical structure, are passed through the review process. This could be monolithic glass, plastic, laminates, applied films on glass, or thin-film coated glass. Diffusing or light redirecting glazing or shading devices are not allowed at present. With the release of Window6 and the CGDB diffuse glazing will be accepted on an experimental basis. A major impediment is the lack of a reliable standard test procedure diffusing components and for complex shading systems.

One type of "attachment" product present in the IGDB is the applied film. Although technically a retrofit product like other types of shading systems, it has the distinction of also being a specular material. Thus, it can easily be incorporated into the technical part of the rating system, although the procedure defined by NFRC 304 is different than for an originally purchased window unit. There is a measurement issue relating to the interference fringes common in applied films that is different from other types of specular glazing.

Can laminates and applied films be calculated?

It is even possible to design new glazing materials such as laminates and applied films by combining sub-components such as glass, interlayer and coating, derived from materials in the IGDB, using the Optics5 software or similar programs. This process is not without potential for mishap as described in the separate blog on the danger of calculated data

    If you are now ready to submit data to the IGDB, jump to the instructions.