Submitting Data

Submitting Data

How to Provide Data to the IGDB

Step by Step:

  1. Overview of Requirements for the IGDB
  2. Qualify to Measure
  3. Choose Your Sample
  4. Product Properties
  5. Measure the Properties
  6. Format the Data
  7. Submit for Review
  8. Pay Fees to NFRC
  9. Review and Acceptance
  10. IGDB Schedule

Overview of Requirements for the IGDB

Before reading further, the potential provider of data to the IGDB should consider whether they can meet the following basic conditions:

  1. Material types: Samples must be flat and specular without patterns. If the samples are diffusing or light redirecting rather than specular they are excluded from the IGDB and cannot be properly treated in WINDOW. Diffusing or light redirecting materials may be acceptable however under the new experimental procedures for the CGDB and WINDOW. Specular materials may be monolithic or have a thin-film coating such as a low-emittance or solar-control coating. They may consist of multiple layers as in a laminate or flexible film applied to a glass substrate.
  2. For measured data only: The database is for measured data only. Data calculated using software tools such as Optics is not allowed in the database.
  3. Properties to be measured: Measurement of transmittance and reflectance must be made over the solar spectrum from 300-2500 nm wavelength using a commercial spectroradiometer equipped with a suitable integrating sphere in accordance with NFRC 300. The reflectance in the thermal infrared must also be measured from at least 5-25 micron in accordance with NFRC 301. If the material is of a known type such as clear (i.e., uncoated) window glass, a default value may be used for the emissivity.
  4. Who can measure: The submitter is typically the glazing manufacturer or independent, third party measurement lab. In either case, the measuring entity must participate in an inter-laboratory comparison (ILC) to qualify. LBNL is not a commercial measurement lab and does not perform routine, service type measurements. LBNL has a research grade instruments and will perform measurements for research purposes or for questionable data resolution purposes or to establish baseline for an ILC. See the list of qualified measurement labs.
  5. Additional information: The submitter must provide the name, appearance, structure and thermal conductivity of the sample.
  6. Formatting the data: The submitter must be able to put the data into the proper format for review and eventual inclusion in the IGDB. Some test labs can provide this service if the primary source of material is not able or not inclined to do it themselves.
  7. Composite products: Properties of a composite material such as a laminate have been calculated from component data using the Optics5 program when all the properties of all the component materials are in the IGDB.

If you think that you can provide data under the above conditions then you should read further and familiarize yourself with the details of the process. Questions about these requirements and all other IGDB related matters should be addressed to

Qualify to Measure

Before the submission process can begin, the laboratory producing the data must successfully participate in an inter-laboratory comparison (ILC) conducted by LBNL. The participating laboratory may be a commercial measurement laboratory or the manufacturer's own in-house lab. If a participant obtains new equipment, assigns a new operator, or simply desires to check compliance, the ILC may be repeated at any time.

Choose Your Sample

The manufacturer is responsible to select and measure a representative sample for the product. Properties of a representative sample:

  • A random sampling of the sold product should have properties equal to, or both higher and lower, compared to the representative sample.
  • The selected sample must be stored for at least four years.
  • Applied film and laminate manufacturers should submit their products on clear glass substrates, preferably 3 mm low-iron, to minimize any influence the substrate has on the submitted data. If the substrate has Tvis =<0.89 and/or Tsol <= 0.83, the product cannot be deconstructed according to NFRC 303 and NFRC 304.
  • Note on deconstructable laminates. The model used in Optics was developed for clear laminates and assumes there is no reflectance from the interlayer. This result in that reconstructed laminates are not much higher reflectance than the substrate properties. Some colored/white laminates have a reflective component that  is not handled by the model, and as this reflectance is not handled by Optics, these products will not be allowed on the NFRC approved interlayer list. The long term solution to this is under  internal discussion.

There is no specified method to choose your sample, but the burden of proof would be on the submitter in the case of a question during peer review or later, so it pays to make a careful choice to avoid more work later. Perhaps for a particular product confidence in quality control is so high that any sample would be as good as any other. On the other hand, the safest and most scientific method would be to do a statistical survey or average over many samples from different factories and different production runs. It is considered prudent to measure several samples and average the properties from the measurements.

Product Properties

The product must be flat and the surfaces must be parallel.

Furthermore the product must be specular in the solar (300-2500 nm) wavelength range. Specular glazings scatter very little light on transmission as well as reflection in the full range.

The easiest way to determine if a product is specular is by using visible inspection, if it looks milky or hazy it is not specular. If you can see a clear and undistorted image through it the product is specular. For the UV and near infrared range a spectrophotometer with an integrating sphere can be used assuming the sphere has a specular exit port. If the ratio between diffuse and total transmittance is less than 0.05 it can be considered specular. The same procedure holds for reflectance.

Measure the Properties

The solar optical properties (300-2500 nm) shall be characterized in accordance with NFRC 300. Data should be recorded at every 5 nm in the solar range.

The thermal infrared properties (5-25 micron) shall be characterized in accordance with NFRC 301. Data should be recorded at least every 1 micrometer. Ideally the infrared properties should be measured from 2.5 up to 40 micron. Measurement of thermal IR properties is not required for uncoated glass but it is still necessary to provide spectral data for the uncoated surface if the other surfece has an applied film or a coating.

Those documents are available from

Format the Data

After measuring the spectral transmittance and the spectral reflectance from both sides of the sample, as specified above, all three datasets are combined into a single file for submission. The format of the data file is well defined and conforms to the long-standing WINDOW text file format. Templates are provided for each type of accepted glazing material.

Please do not submit files with names containing more than 30 characters (including the extension) File extensions — at this time, it is not possible to change the file extensions. We plan to implement this capability in the future, but for now, it is necessary to continue to use the file extensions originally assigned

Caution: There are many instances in these examples which contain the word "reference" in the title. The first- time data submitter is advised to avoid these data types for now. They refer to cases which can be "deconstructed" in Optics5 and then recombined with other components to calculate the properties of a variant on the original glazing. See the general warning on calculated data. This entire section will be rewritten here with proper instructions for safe use of "reference" files.

First time submitters have to request an ID block for their manufacturer name, as well a deciding which 3 letter suffix their files shall have. This is done by contacting the email address.

Submit for Review

First time data submitters should provide the following information:

  • A file extension for your files. This extension cannot be changed at this time. All your data files should be submitted with this file extension.
  • The number of products you intend to include in IGDB. We assign a block of ID numbers to each manufacturer. This block cannot be expanded at this time so please choose this number very carefully.

A Data Submission Spreadsheet is required with each data submission.

The preferred method is to email the files of the submission. The address to use depends on the regional data aggregator (RDA), currently everyone but European submitters should email LBNL with the address European manufacturers should email the European RDA, where the contact person is Helen Rose Wilson at Fraunhofer ISE, using the address  There are forms that need to be provided with the data. The LBNL data submission form is also attached to this page and the NFRC glass measurement location and glass supplier contact form is on the NFRC site.

If a manufacturer’s data is to be submitted by a third party, and the third party will be listed as the Manufacturer in the IGDB, in essence “re-branding” the product, the third party must have the product measured and submit it to the normal IGDB review process independent of any submittals under the original manufacturer’s name. The submittal must indicate, for each product submitted, the original product manufacturer.

In addition, the third party must obtain permission from the original manufacturer for both submitting the data and for re-branding the product. This permission must be submitted to Lawrence Berkeley National Laboratory (LBNL) in the form of a letter from the original manufacturer, on their company letterhead, listing the products that will be re-branded. If the manufacturer has submitted data to the IGDB under their own name, this letter must come from the manufacturer’s IGDB contact. This letter (or letters if the products are from multiple manufacturers) must accompany the data submission forms. In the case where the manufacturer wishes to discontinue having the re-branded product in the IGDB, another letter from the manufacturer must be submitted to LBNL.

Pay Fees to NFRC

At this time NFRC requires payment of fees for all products in the IGDB. If data is submitted directly to LBNL, the intent of the data provider to obtain NFRC ratings will be determined and NFRC will be so informed. NFRC approved files will be so marked in the IGDB. The fee schedule is available on the NFRC website. This policy may be changed at any time at the sole discretion of NFRC.

Review and Acceptance

This final stage consists of waiting for the review to quietly conclude. Sometimes there are questions from the LBNL internal reviewers or the peer reviewers that require checking and resubmission of data. All data submitters automatically become members of the peer review group and will receive emails with data that is being considered for the next IGDB update. This is not meant to be a test or an impediment, but a cooperative process leading to proper submission of accurate data. The requirements on technical review and peer review are given in NFRC 302, Sections 3.5-3.8. Each submitter is given a reserved block of NFRC ID numbers.

IGDB Schedule

There are currently six IGDB releases per year. Data submitters should follow the schedule below for their data submission. Due to the short processing time, we will no longer accept more than 100 submissions or requests for modification/change from each manufacturer, in each cycle.

Release Number Submission Deadline Data Goes to Peer Review End of Peer Review Release Date
1 12/20 1/10 1/31 2/10
2 2/20 3/10 3/31 4/10
3 4/20 5/10 5/31 6/10
4 6/20 7/10 7/31 8/10
5 8/20 9/10 10/1 10/10
6 10/20 11/10 12/1 12/10
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