Comparison of AAMA/WDMA/CSA 101/I.S.2/A440 (NAFS) 2008, 2011 and 2017 Versions

AAMA and WDMA, as sponsors of AAMA/WDMA/CSA 101/I.S.2/A440 North American Fenestration Standard/Specification for windows, doors and skylights (NAFS), have conducted a side-by-side comparison of the testing and specification differences between the 2008, 2011 and 2017 editions of the standard. The equivalency bulletin aims to show the user how all three editions correlate to one-another, and should be used as a tool in conjunction with the NAFS standards available for purchase in the FGIA Online Store.

Tracing their origins back to 1947, AAMA performance standards for fenestration products have served as an indispensable resource for architects, specifiers, contractors and manufacturers seeking to pinpoint optimum, material-neutral performance levels to meet the needs of specific projects and localities. 

Today, NAFS defines basic performance requirements for a wide variety of styles of window, door and skylight products (double-hung, casement, horizontal sliding, etc.) made of aluminum, vinyl (PVC), ABS plastics, fiberglass, cellulosic composites and wood, as well as those with aluminum- or vinyl cladding. It relies on Performance Class and Performance Grade designations to guide this evaluation and selection process.

Performance Class roughly describes the likely target application in four steps with increasing exposure severity ranging from single-family residential to high-rise commercial buildings.

Performance Grade is a numeric designator that defines a specific set of NAFS-specified product performance requirements for a specific Design Pressure (DP) range as required by conditions at the intended location of the building. A product achieves a Performance Grade rating only upon successful completion of all applicable tests–primarily those for structural performance under wind loading and for resistance to water penetration and air leakage.

Fenestration standards are always evolving due to changes in technology, building codes and rating system performance requirements. The performance-based, material-neutral NAFS governing windows, doors and skylights is no exception. This material-neutral omnibus guidepost for fenestration specifiers, has been evolving ever since 1997 and serves as the basis for product certification as required by IBC and IRC.

Changes from the 2008, 2011 and 2017 versions of the standard (referenced in the International Building Codes and available as the basis for AAMA’s nationally-recognized, ANSI-accredited third-party testing and Gold Label Certification Program) include key aspects of the performance standards.

Performance Classes
Operator Types

Performance Classes

Changes in the 2008 version of NAFS realigned and reduced the total number of the Performance Class designations as defined by the Performance Grade (a set of performance requirements corresponding to a Design Pressure range) at the intended location of the building. This simplifies the specifier’s task in matching fenestration performance to project requirements and consolidates testing requirements for manufacturers.

In the 1997,  2002 and 2005 editions, there were five Performance Classes: R, LC, C, HC and AW. For the 2008 edition, the C and HC performance classifications were eliminated and replaced with a singular CW classification. There have been no further changes to the performance classifications since 2008, which are currently defined as:

• R: commonly used in one- and two-family dwellings
• LC: commonly used in low-rise and mid-rise multi-family dwellings and other buildings where larger sizes and higher loading requirements are expected
• CW: commonly used in low-rise and mid-rise buildings where larger sizes, higher load requirements, limits on deflection and heavy use are expected
• AW: commonly used in high-rise and mid-rise buildings to meet increased loading requirements and limits on deflection, and in buildings where frequent and extreme use of the fenestration products is expected

For more information, visit the Performance Class Overview web page.

Operator Types

Changes from the 2008 to the 2011 versions added more operator types and restructured contents for more intuitive access. The 2011 version of NAFS addressed 36 operator types, an addition of five compared to the 2008 version. 

Five added operator types (2011):

• Mullion Assembly (MA) is defined as the unit formed by joining two or more individual fenestration units together with a horizontal or vertical member. If tested as a combination assembly, the individual units making up a factory-made combination assembly must also qualify as individual units. Combination assemblies with mullions between separate window or door unites can be qualified by testing as a single combination unit or by testing as individual units. The mullion performance is tested separately or calculated for air, water and structural performance in accordance with AAMA 450, Voluntary Performance Rating Method for Mulled Fenestration Assemblies. Field-mulled units are not covered.
• Parallel Opening Window (POW) is defined as a window consisting of an operable sash that moves horizontally outward perpendicular to the plane of the frame and remains parallel to the frame throughout its range of motion.
• Secondary Storm Product (SSP) is defined as a door, window or skylight product intended to be used only in conjunction with, and attached to the internal or external frame or sash of, a primary window, door or skylight product for the purpose of enhancing performance in a system with the primary product. Performance levels for SSPs, as determined by design pressure (DP) for the building's location, range from 15 to 100 psf. The uniform structural load test pressure, applied in both positive and negative directions, is 150 percent of the DP and pressure for the water test (required for externally applied units) is 10 percent of DP. Air leakage test pressure is the same at all performance levels - 1.57 psf. The maximum allowable air leakage rate must be:
• For externally applied operating windows and externally applied fixed removable windows: 1.0 cfm/ft of net sash crack perimeter
• For internally applied operating windows and internally applied fixed removable windows: 0.5 cfm/ft of net sash crack perimeter
• For externally applied sliding glass storm doors: 1.0 cfm/ft2 of overall frame area
• Tubular Daylighting Devices (TDDs) are defined as non-operable fenestration units primarily designed to transmit daylight from a roof surface to an interior space and generally consisting of an exterior glazed weathering surface, a light-transmitting tubular conduit with a reflective inner surface and an interior closure glazing in a retainer frame. In closed-ceiling installations, the tubular conduit passes through unconditioned space; while in open-ceiling versions, the tubular conduit is suspended in conditioned space.
• The Roof Window (RW) category has been split into two categories: glass glazed (RWG) and plastic glazed (RWP).

Changes from the 2011 to the 2017 versions added more operator types, including Folding Door (FLD) System, Limited Water Folding Door (LWFLD), Top Turn Reversible (TTR) and Tropical Awning Window Secondary Storm Product (TASSP). Also added was the ability to label a door system as tested without hardware by adding an "X" to the door designation.

Five added operator types (2017):

• Folding Door (FLD) System is defined as a door system that has, at a minimum, a hinge or pivot attachment of any type between two leaves (panels) and three vertical axes about which the leaves rotate. The leaves can be folded to the interior or exterior of the opening. These systems are either top hung or bottom supported by hardware that attaches to a single track system and include, at a minimum, two pivoting/folding leaves, a frame, and a track and roller assembly. The frame has vertical and horizontal members that are joined at the intersections that fully encompass the operating and inactive leaves in a closed position. A flush set track assembly can exist in place of a sill assembly. Additional hinged and pivoting/folding leaves and/or a single-side-hinged leaf can be included in the door system.
• Limited Water Folding Door (LWFLD) is defined as a Folding Door System that is limited water. Limited water is a product designation that indicates that the water penetration resistance performance was achieved by testing at a pressure less than the minimum test pressure required for the indicated Performance Class and Performance Grade (PG).
• Top Turn Reversible (TTR) Window is defined as a window consisting of an operable sash hinged on each vertical side that projects outward from the plane of the frame at the bottom but then pivots to allow complete reversibility of the sash. The opening can be limited in a pre-determined position for safety or to hold the sash in a position under wind load. The sash is restricted in the fully reserved position for safety during cleaning.
• Tropical Awning Window Secondary Storm Product (TASSP) is defined as a Secondary Storm window consisting of one or more top-hinged or pivoted sash that swing outward at the bottom edge and are operated by one control device that securely closes them at both jambs without the use of any additional manually controlled locking devices. A secondary storm product can be attached to the internal or external frame or sash of the primary product. A secondary storm product is also considered a secondary door or secondary window.
• Door System as Tested without Hardware (for example, DASHDX) is defined as a system that is tested with the hardware excluded. This is done for systems when the hardware is sold independently of the door and therefore testing of the combination is not appropriate.

The following table lists the NAFS-17 recognized operator type designation codes, along with their full description. Those added in the 2011 version appear in red, and those added in the 2017 version appear in blue.

NAFS-17 Recognized Operator Types

* Tubular Daylighting Devices are split into two categories for closed-ceiling and open-ceiling installation.

NAFS Comparison Chart

View a comparison chart that provides additional details relating to the differences between the 2008, 2011 and 2017 NAFS versions.

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