The National Fenestration Rating Council (NFRC) held a special virtual meeting of the Research Subcommittee yesterday and one of the main agenda items was deciding whether the NFRC should proceed with two proposed research projects. Ultimately, members voted no to both proposals so they will not move to the request for proposal (RFP) stage for the fall meeting.

The first ballot, “Develop Artificial Daylighting Source for Solar Calorimeter Testing,” was proposed by Bipin Shah, WinBuild Inc., and Dr. Ross McCluney, Sunpine Consulting.

The background information in the ballot pointed out that NFRC calls for the use of an outdoor solar calorimeter for solar heat gain coefficient (SHGC) measurements, which tracks the sun at normal incidence. While it uses an actual solar spectrum, this testing procedure has inherent problems of maintaining a controlled environment and limits the use of equipment to only during clear sky and moderate wind conditions. These outdoor environmental limitations in different location and climate zones restrict the use of the solar calorimeter especially in regions where there is significant cloud cover and windy climates.

Several countries currently are looking into developing Solar Calorimeter testing procedures and facilities, according to the proposal. These countries are strongly considering the use of indoor testing facilities, currently the predominant approach in European countries. Thus, research was proposed to investigate the availability and/or development of a solar simulating electrical source having both good solar spectral range coverage and a reasonably acceptable spatial and directional distribution of the flux on a target large enough to include most fenestration systems that could be tested with this approach.

Benefits cited by its proponents included: Improved testing methodology with reduced discrepancies in solar calorimeter testing results that will better meet the NFRC’s mission of fair, accurate and credible ratings and will help increased international harmonization.

One member in attendance said it was too early for the ballot to be going forward while another agreed that it “is slightly premature.”

While the motion to proceed with the research failed, committee members indicated they may modify the ballot and bring it back at a later date.

The estimated cost of the project was $100,000 to $125,000 and the proposal estimated it would have taken approximately ten months to complete.

The second ballot, “Testing and Calibration of a CTS Panel with a Roomside Surface low-E Coating,” was proposed by the NFRC’s Testing Laboratory Task Group.

Background information provided in the ballot pointed out that fenestration products have become more popular with the placement of low-E coatings on the interior-most surface to help lower U-factors. As part of the NFRC certification process, testing laboratories are to validate the simulations by conducting an NFRC 102 thermal performance test to determine the U-factor. Therefore, if a fenestration manufacturer was to submit a test specimen that had a low-E coating on the inner-most surface (for example: on surface #4 of a dual-glazed IG system), it is highly likely it would not validate because the accuracy of the testing being conducted does not take into account the reflective/absorptive abilities of the low-E coating, according to the proposal.

NFRC conducts an Interlaboratory Comparison (ILC) every year to ascertain the uniformity of each of the NFRC accredited thermal testing laboratories by testing a single test specimen, according to the ballot. The 2010 Thermal Test ILC determined that there was an issue with the calculation of the standardized U-factor of this product, per ASTM C1199 and NFRC 102. None of the laboratories were able to validate the product against the simulated U-factor by using the current calibration procedures. Current calibration procedures require the use of a Calibration Transfer Standard (CTS) to determine the chamber’s interior and exterior film coefficients (basically, adjustment of the proper interior and exterior wind velocities). This CTS is required to have clear glazing (glass or plastic) on both sides of a calibrated foam material (typically EPS or expanded polystyrene), according to the proposal.

Because the CTS has clear glass surfaces, it is undetermined if the chambers are in fact calibrated to test fenestration products with exposed low-E coatings.

The research was proposed to investigate whether thermal chambers are required to be calibrated with CTSs including a low-E coating on the inner-most surface before testing and validating any fenestration product with low emissivity exposures.

The benefits cited in the proposal included: Improved testing methodology with accurate U-factors for products physically tested for the Independent Verification Program, test-only or validation for initial or re-certification per the NFRC 700 program.

“I wonder if this is worth the investment,” said Thomas Culp, owner of Birch Point Consulting LLC. “I am not sure we need to do it. In my view it is already done.”

Another member pointed out that the objective of the research is to harmonize international standards but the international players aren’t involved in this.

“So it’s a valuable effort but this isn’t the right approach as it seems like we want to come up with something, then just have others adopt it and that’s not the right approach,” he said.

The estimated cost of the project was $25,000 to 35,000 and would have taken approximately six months.


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