2026 North American Fenestration Standard
The North American Fenestration Standard (NAFS), which covers specifications for windows, doors, and skylights, is a prime example of the drive to harmonize industrial practices.
What Is the North American Fenestration Standard (NAFS)?
Jointly developed by the American Architectural Manufacturers Association (AAMA), the Window & Door Manufacturers Association (WDMA), and CSA Group, the newest revision of the North American Fenestration Standard/Specification for windows, doors, and skylights is AAMA/WDMA/CSA 101/I.S.2/A440-2026. This joint standard is the latest effort in a long persisting series of tasks carried out to harmonize standards in North America. With its publication, the document demonstrates the fenestration industry’s desire to unify its customers and professionals, eliminating barriers wherever possible.
AAMA/WDMA/CSA 101/I.S.2/A440-2026 sets forth levels of performance for windows, doors, secondary storm products (SSPs), tubular daylighting devices (TDDs), roof windows, and unit skylights, establishing a rating system of performance grades, design pressure, and related performance ratings, as well as testing protocols.
Levels of performance addressed in AAMA/WDMA/CSA 101/I.S.2/A440-2026—through the guidelines for
structural strength, water penetration resistance, air leakage, operating force, and forced-entry resistance—provide a gateway into one of the four Performance Classes: R, LC, CW, and AW, ordered least to most stringent.
Who Uses The North American Fenestration Standard?
Intended users of AAMA/WDMA/CSA 101/I.S.2/A440-2026 include building officials, manufacturers, architects, engineers, consumers, builders, contractors, trade associations, test laboratories, specifiers, product evaluation and certification agencies, and government agencies. Two fundamental applications of NAFS-2026 are product comparison and code compliance.
Changes to AAMA/WDMA/CSA 101/I.S.2/A440-2026
Revising and superseding the 2022 edition of the same standard, AAMA/WDMA/CSA 101/I.S.2/A440-2026, was updated to keep it current and fulfill the objectives of the three organizations that developed it. The primary change made to NAFS-26 clarifies requirements for the secondary designator used in fenestration product ratings.
AAMA/WDMA/CSA 101/I.S.2/A440-2026: North American Fenestration Standard / Specification for windows, doors, and skylights is available on the ANSI Webstore.
