Volume 36, Number 3, March 2001

Fenestration Focus


Why Certify?

Consider the Benefits of Third-Party Certification

by Jim Benney

cavemanIn the beginning, there was Ogg. Ogg would travel the land providing cave dwellers with openings that offered additional ventilation, a view of the environment and an extra point of egress. The opening, or fenestration, would be provided in accordance to the cave dweller’s specifications. It is unknown what warranties or guarantees were provided by Ogg, but we do know that in the Code of Hammurabi, a builder whose careless workmanship caused death, lost his life or paid for it by the death of his child, replaced slave or goods. He had to rebuild the cave or make good on any damages due to defective building and had to repair the defect.

While this story may not represent the modern window industry, it provides a backdrop for how and why third-party certification programs exist (specifically the National Fenestration Rating Council [NFRC] program) and the benefits these provide to the industry and the population at large.

In this article, I have identified three benefits of third-party certification for fenestration products (windows, doors, curtainwalls and skylights). These are standardization, labeling and market transformation.

The NFRC has been in existence for more than ten years. Prior to the formation of NFRC, window manufacturers, curtainwall suppliers and other fenestration industry representatives were utilizing numerous methods for determining window thermal performance, including:
~    Center of glass U-factors, R-values and shading coefficients;
~    Calculations based on various heat transfer models;
~    Default values from the ASHRAE Handbook of Fundamentals;
~    Tested values based on any one of three separate test methods.
The information being presented to distributors, installers, architects, contractors, builders and the public was confusing at best and misleading at worst. Now, NFRC has a standardized rating methodology for thermal transmission (U-factor), solar heat gain coefficient (SHGC), visible transmittance and air leakage performance of window, door and skylight systems. In addition to these published standards, NFRC has a system of checks and balances in place to assure the credibility of these ratings. All certified performance ratings must be determined by an NFRC-accredited simulation laboratory, validated by an NFRC-accredited test laboratory and verified by an accredited inspection agency.

Communication and Enforcement (Labeling)
An obvious benefit of third-party programs is the use of highly visible labels to communicate the energy rating for windows, doors and skylights. NFRC developed and adopted a standard label that is to be applied to each certified unit. In states such as Cali-fornia, Oregon and Washington, all manufactured window units are to be labeled so, or meet the requirements through published default ratings. These labels allow for ease of compliance by building officials when determining whether or not a building meets the local code requirements.

These labels and the Certified Products Directory (which maintains product listings) are also helpful to builders, architects, specifiers and building owners for comparing different potential suppliers with realistic product-to-product performance ratings.
In the case of site-built (or field-glazed) products, NFRC developed a label certificate as a paper trail for the building inspector, commissioning agent or other party to communicate (and compare) the thermal performance of commercial fenestration systems in a fair and accurate manner. These label certificates address the impracticality of having temporary and permanent labels on every opening in a multi-story residential or non-residential building project. As with the NFRC label, these standardized forms include the NFRC logo, U-factor, SHGC and visible transmittance of the certified products installed on a building. The NFRC ratings are established on standardized specimen, using the specified framing and glazing systems.

In addition, the label certificate form, posted on site of a building project, will provide building officials with the documentation needed to show compliance with local and state energy code requirements. The label certificate was developed in a standardized form and made to be easily recognized, with the energy ratings provided in a legible format for each fenestration system on a building project. Copies of each NFRC label certificate are maintained by the responsible party, the third-party independent administrator and at the NFRC office.

Market Transformation
The third benefit of third-party certification is probably the least known, but possibly has the biggest impact. The use of NFRC labels and label certificates are essential to provide high-performance fenestration products with the recognition they deserve. Traditionally, solar gain into buildings through the glass has been controlled by reflective or tinted products. However, there are many new glass products on the market that can achieve the required U-factor and SHGC that appear to be transparent, like clear glass. These spectrally-selective glass products have a thin metallic, low-emissivity coating that allows visible light to be transmitted through the glass but blocks the solar gain (due to infrared light).

In addition, there is solar gain transmitted into buildings via the aluminum framing systems. Traditionally, the effects of the frame on solar heat gain have been disregarded in determining the performance of curtainwall and storefront systems. NFRC requires that ratings be determined for the entire fenestration system, including the effects of the frame, edge and sash. Depending on the SHGC of the glass, a non-thermally broken aluminum frame can increase solar gain by 10 percent or more if the frame is a dark color. There are, however, a number of thermally-improved and thermally-broken aluminum framing systems, which will not increase the solar gain through the fenestration and can even improve it.

The NFRC certification program not only provides confirmation that the glass and framing system specified for a project are being installed on the building. It also assures the glass and frame supplier that their high-performance products are getting the recognition in the market and the energy credit they deserve. NFRC certification is required for programs such as ENERGY STAR® and other energy-efficient building programs. It is the only way to assure the supporters of these programs that the consumers (and customers) are receiving the benefits they pay for.

In conclusion, the benefits of third-party certification far outweigh the costs associated with its use. Without NFRC and other third parties, the federal government would no doubt be implicating our friend Ogg for not complying with Hammurabi’s code, rather than supporting market transformation programs.

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