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May - June 2003


Tracking a North American 
Window Standard
by Carl Wagus

Much effort has been devoted in recent years to the development of a single window and door standard that meets the requirements of all North American markets, simplifying product design and manufacturing while expanding marketing opportunities. Several iterations later, the second edition of such a standard (originally christened the North American Fenestration Standard) is undergoing initial balloting. Because the evolutionary steps and resulting changes in nomenclature may be confusing to those of us not in the front lines of standards development, it’s a good time to clear things up and clarify what the requirements are today.

An Effort to Harmonize
The lynchpin of this development effort was hammered into place in 1997, with the release of ANSI/AAMA/NWWDA 101/I.S. 2-97, “Voluntary Specifications for Aluminum, Vinyl (PVC) and Wood Windows and Glass Doors.” This was the first truly non-prescriptive, performance-oriented and material-neutral basis for comparing the key performance characteristics and quality attributes of all window and door products. This standard superseded ANSI/AAMA 101-93 and NWWDA I.S.2-93 and encompassed products made of aluminum, vinyl or wood, as well as those with aluminum- or vinyl-clad wood framing members.
As big a landmark as 101/I.S. 2-97 was, work continued toward the full harmonization of U.S. and Canadian standards.

The first result was the so-called North American Fenestration Standard (NAFS-1) based on ANSI/AAMA/NWWDA 101/I.S. 2-97 and Canada’s CSA A440. Later officially named 101/I.S. 2/NAFS-02, “Voluntary Performance Specification for Windows, Skylights and Glass Doors,” this new milestone in fenestration standards was proposed for approval by the American National Standards Institute (ANSI) as an American National Standard in early 2002. Final ANSI approval was given on February 6, 2003. In October 2002, it was accepted by the International Code Council (ICC) for the International Residential Code (IRC) and International Building Code (IBC), to take effect officially as of January 1, 2003. The IBC and IRC therefore recognize both 101/I.S. 2/NAFS-02 and ANSI/AAMA/NWWDA 101/I.S. 2-97.

To What Shall We Certify?
The AAMA certification policy committee has developed the following schedule for AAMA’s phase-in of 101/I.S. 2/NAFS-02 as the basis for certifying products.

• As of December 1, 2003, all products to be certified or re-certified must be certified to 101/I.S. 2/NAFS-02, but may also be certified to 101/I.S. 2-97.l.

• Existing certifications to 101/I.S. 2-97 will continue to be valid until their four-year expiration dates.

• Products may continue to be certified to 101/I.S. 2-97 (along with 101/I.S. 2/NAFS-02 certification) until 101/I.S. 2-97 is removed as a reference from the international codes.

• When 101/I.S. 2-97 is removed from the international codes, AAMA will cease issuing new or renewed certifications for 101/I.S. 2-97. However, all certifications that are in effect at that time will remain in effect until their four-year expiration dates. This transition period will allow continued certification to 101/I.S. 2-97 for those code jurisdictions in which it may continue to be required and will minimize the impact on certifying manufacturers. 

101/I.S. 2/NAFS-02: 
The Changes
101/I.S. 2/NAFS-02, though something of a clone of 101/I.S. 2-97, and more or less a work in progress from the standpoint of full international harmonization, does introduce a number of important changes. 

Metric Units. As an international standard (albeit focused on North America), it features metric units and addresses performance measurables used in code jurisdictions other than those in the United States. 

Product Designation. While the product designation system represents a distinct change from the three-part rating used currently in Canada, it meets all of the current requirements in A440 and the National Building Code of Canada. 

New Products Added 
101/I.S. 2/NAFS-02 makes some important additions to the list of products covered by the standard, notably:

Skylights and Roof Windows: The intent is for 101/I.S. 2/NAFS-02 to absorb and supersede the old AAMA/WDMA 1600/I.S. 7 standards governing these products. Separate product designations are defined for glass-glazed skylights (SKG), plastic-glazed skylights (SKP) and roof windows (RW).

Sidelites (SLT) and Transoms (TR): Under 101/I.S. 2-97, these were treated as varieties of fixed (“F”) window products. 101/I.S. 2/NAFS-02 recognizes that the framing of these products usually differs from that of typical picture windows and defines appropriate performance requirements for them.

Specialty Products (SP): This category was established to clarify how performance is to be measured for size and shape variations of other product types (e.g., half-rounds, trapezoids and other configurations) and is congruent with current National Fenestration Rating Council terminology. Note that this does not replace the specialty products grouping defined in 101/I.S. 2-97, so the existing categories for basement, greenhouse, jalousie, etc., windows still stand.

Higher Performance Requirements
While the design and test pressures remain the same in 101/I.S. 2/NAFS-02 as in 101/I.S. 2-97, the minimum performance bar under the uniform load structural test has been raised for some product classes. 
• For commercial (C) and heavy-commercial (HC) windows, there can be no permanent deformation of any mainframe, sash, sash member or panel in excess of 0.3 percent of its span (versus 0.4 percent under 101/I.S.2-97). 

• Air infiltration test pressure is now 300 Pa (6.24 lb/ft2) for the HC class as well as the AW class, representing a significant minimum performance upgrade. 

• The water-test pressure is now capped at 15 psf (720 Pa) instead of the 12 psf referenced in 101/I.S.2-97. This allows testing for the conditions found in the Maritime Provinces of Canada and also those often specified in the hurricane prone regions of the United States.

Minimum Test Sizes Increased
Test size is a critical factor in determining a product’s conformance with the standard. A minimum test size for each performance class is specified for each window type. Product specimens must be tested at the specified minimum size or larger as a gateway condition for entering the performance class. The performance class designation assigned to the product as a result of the tests may then be applied only to production units of the same size as the indicated test size or smaller. This provides a uniform basis for comparing the performance of different manufacturers’ windows of the same grade and type.

Several changes were required in the sizes to accommodate the differing size requirements in the base standards. An extensive survey was conducted of all product data available from both Canada and the United States. This data showed that more than 85 percent of the tested products were tested at the sizes now included in the new standard or larger. Much of the work of the task force was devoted to the assurance that the test sizes were fair and equitable and adequately.

New Maximum Optional Performance Levels
Like 101/I.S. 2-97, 101/I.S. 2/NAFS-02 makes it possible to specify higher uniform load structural test and water-resistance test pressures. What’s new is that 101/I.S. 2/NAFS-02 sets maximum performance levels at which a product (except skylights) may qualify within each performance class (except for the AW grade, for which no maximum is set), by capping the maximum performance grade (design pressure) at 2880 Pa (60 psf) above the minimum (gateway) level for each class. 

The Latest Incarnation
Although 101/I.S. 2/NAFS-02 has made significant strides, it did not quite reach the goal of full harmonization of U.S. and Canadian standards due to some relatively minor outstanding, unresolved issues. Therefore, an update was already on the drawing boards to iron out these remaining issues even as 101/I.S. 2/NAFS-02 was being released. Unfortunately, the update had become known in standards development circles as “NAFS-2,” even before NAFS-1 was renamed 101/I.S. 2/NAFS-02–certainly a potential source of confusion! But once you get past that confusion, you will see how useful the new standard will be to the fenestration industry.

A draft of the newest specification, officially dubbed 101/I.S.2/A440 (a.k.a. NAFS-2), was released for public review and comment in January 2003. 

Jointly developed by the U.S./Canadian Structural Harmonization Task Force, 101/I.S.2/A440 (a.k.a. NAFS-2) will be offered for ANSI approval once public comments are resolved and balloted among the developing organizations. The harmonization task force is composed of six representatives each from Canada and the United States. U.S. representation is divided evenly between representatives of AAMA and WDMA. Canadian members represent the NRC/IRC laboratory councils, CWDMA and CSA. The task group intends to propose the new specification for reference in the United States “I Codes” and the National Building Code of Canada in the 2005-2006 time period.

Though very similar in format to 101/I.S. 2/NAFS-02, the current draft of 101/I.S.2/A440 does include some significant changes:

• A new specification for side-hinged exterior doors developed by the joint exterior door task group has been added;

• The commercial performance class has been deleted, and the requirements for heavy- commercial have been revised accordingly;

• The words residential, light-commercial, heavy-commercial and architectural are eliminated from the definition of the performance classes. The classes now are designated simply as R, LC, HC and AW;

• A limited water rating has been introduced for side-hinged doors;

• The product rating system is being expanded to provide a primary designator similar to that in current use and a new secondary designator, that allows the reporting of performance criteria such as negative test pressures, optional performance criteria and water test pressures;

• The gateway requirements are being revised to a metric basis while still maintaining the IP (psf) nominal rating intervals common to previous specifications;

• New testing requirements have been added for side-hinged doors that include cycle/operation testing, hardware water testing, vertical load testing and forced-entry resistance testing; and

• Numerous new sash, frame and glazing material requirements have been added.
So, even as 101/I.S. 2/NAFS-02 is lined up for certification, work continues to refine the requirements in the upcoming 101/I.S.2/A440 version. As technology changes, and as market needs evolve, a standards developer’s work is never done! 

Carl Wagus is the technical director at the American Architectural Manufacturers Association, which is based in Schaumburg, Ill. 

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