Changes to Performance Classes and Operator Types
Comparison of AAMA/WDMA/CSA 101/I.S.2/A440-05, AAMA/WDMA/CSA 101/I.S.2/A440-08 and AAMA/WDMA/CSA 101/I.S.2/A440-11
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, AAMA/WDMA/CSA 101/I.S.2/A440–the North American Fenestration Standard (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 North American Fenestration Standard (NAFS) governing windows, doors and skylights, AAMA/WDMA/CSA 101/I.S.2/A440, is no exception. The 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 2005, 2008 and 2011 versions of the standard (referenced in the 2012 International Building Codes and available as the basis for AAMA’s nationally-recognized, ANSI-accredited third-party testing and Certification Program) include key aspects of the performance standards.
Changes from the 2005 to the 2008 version of AAMA/WDMA/CSA 101/I.S.2/A440–the North American Fenestration Standard (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 consolidate testing requirements for manufacturers.
In the 1997 and 2002 editions, there were five Performance Classes, described as: “R” for Residential, “LC” for Light Commercial, “C” for Commercial, “HC” for Heavy Commercial and “AW” for Architectural. The descriptions were intended to act as a general guide in helping to determine which class was best suited for a particular application. In the 2005 edition, the five performance classes remained, but the market sector descriptions were deleted, as the choice of Performance Class is increasingly made somewhat independently of the use of a building.
For the 2008 and 2011 editions of NAFS, the C and HC performance classifications were eliminated. In their place is a “CW” classification, which reduces the total number of performance classifications from five to four.
For more information on performance classes, visit the Performance Class Overview web page.
Change from the 2008 to the 2011 versions added more operator types and restructured contents for more intuitive access. The 2011 version of NAFS addresses 36 operator types, an addition of five compared to the 2008 version. The following table lists these, along with their type designation codes. Those added in the 2011 version appear in red.
|AP = Awning, hopper, projected window||POW = Parallel opening window|
|ATD = Architectural terrace door||RWG = Roof window — glass glazed|
|BW = Basement window||RWP = Roof window — plastic glazed|
|C = Casement window||SD = Sliding door|
|DASHD = Dual-action side-hinged door||SHD = Side-hinged door|
|DAW = Dual-action window||SHW = Side-hinged (inswinging) window|
|FD = Fixed door||SKG = Unit skylight — glass glazed|
|FW = Fixed window||SKP = Unit skylight — plastic glazed|
|GH = Greenhouse window||SLT = Side lite|
|H = Hung window||SP = Specialty product|
|HE = Hinged rescue window||SSP = Secondary storm product|
|HP = Horizontally pivoted window||TA = Tropical awning window|
|HS = Horizontal sliding window||TDDCC = Tubular daylighting device — closed ceiling*|
|J = Jalousie window||TDDOC = Tubular daylighting device — open ceiling*|
|JA = Jal-awning window||TH = Top-hinged window|
|LW DASHD = Limited water dual-action side-hinged Door||TR = Transom|
|LW SHD = Limited water side-hinged door||VP = Vertically pivoted window|
|MA = Mullion assembly||VS = Vertical sliding window|
for closed-ceiling and open-ceiling installation.
The five newly added operator types are:
- 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 units 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 secondary storm products (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).
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