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Colonial Style Window design, Clinton Hill Brooklyn (C) Daniel Friedman Guide to Window Certifications, Standards, Ratings

Window standards:

What are the various window certification agencies and guidelines and associations: In this article series we discuss the certifications and standards for the performance of windows.

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Window Certification & Standards

Hurricane resistant windows required in parts of Floirida (C) Daniel FriedmanIn this article series we discuss the selection and installation of windows and doors, following best construction and design practices for building lighting and ventilation, with attention to the impact on building heating and cooling costs, indoor air quality, and comfort of occupants.

This article includes excerpts or adaptations from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) , by Steven Bliss, courtesy of Wiley & Sons.

Photo at left: Florida requires hurricane and wind-resistant windows in some areas.

[Click to enlarge any image]

It is always best to choose windows with third-party certification from American Association for Window Manufacturers (AAMA) or the Window and Door Manufacturers Association (WDMA, formerly the National Wood Window and Door Association, NWWDA).

Both the AAMA and WDMA are trade associations representing manufacturers of windows, doors, and skylights.

The WDMA is limited to wood windows and doors, while the AAMA encompasses a wide range of materials, from wood, aluminum, vinyl, and fiberglass to the newest composites.

 

Voluntary Standards for Window Manufacturers

In 1997, the two groups joined forces to establish a unified standard for evaluating fenestration products, known as AAMA/NWWDA 101/I.S. 2-97 “Voluntary Specification for Aluminum, Vinyl and Wood Windows and Glass Doors.” It establishes four performance requirements for a completed window or door.

Products that are certified under 101/I.S. 2-97 are designated by a four-part code that denotes the type of window, the performance class, and performance grade. For example, the code C-R15 indicates a casement window (C) recommended for residential applications (R), with a performance grade of 15.

Performance Grade and Design Pressure for Windows: "Wind resistance".

How well a window performs when subjected to heavy rains and high winds is indicated by its performance grade and design pressure.

The window design pressure (in psf) given below is a structural rating only, while the performance grade also indicates that a window has met the water resistance and air infiltration standards for that grade (see Table 3-2 below).

(C) J Wiley, S Bliss

[Click to enlarge any image, photo or table]

The minimum recommended design pressure for residential doors and windows is 15 psf.

A design pressure of 15 means a window has been tested to withstand sustained wind pressures of 22.5 psf, roughly equivalent to a 95-mph wind, applied to either side of the window, simulating both positive and negative wind pressures.

The test pressure is always 150% of the rated design pressure to provide a safety factor.

To earn a performance grade of 15, a window must also pass a water pressure test of 2.86 psf, which simulates rainfall of 8 inches per hour with a wind speed of 34 mph. In coastal areas or other areas prone to heavy winds or hurricanes, higher grade windows are recommended and may be required by code.

Window Design Pressure Ratings actually combine the window's resistance to water leaks, air leaks, and actual structural loading, where higher psf ratings mean a better window resistance to these three effects.

Window or Door PG or Performance Grade Ratings

A more-recent window performance rating scale are PG ratings.

Window PG-Ratings combine separate evaluations of a window's resistance to water infiltration, air infiltration, and structural loading failure by assigning points to the window's ability to resist each of those forces and then computing a total Window Performance Grade Rating number.

The result is a number that might describe a window that is very resistant to water and air leaks but has less resistance to structural failure - for example.

A hurricane-resistant entry door might score very high for wind resistance against structural failure: the door won't "blow in", but it's PG-Rating might be lowered if the door leaks air or water during hurricane conditions.

Watch out: window and door performance ratings described here do not mean that the window or door has that same level of resistance to airborne objects nor to sudden wind gusts that might occur during a tornado or hurricane.

Industry Associations for Windows & Doors

Fenestration Performance Classes, Sources, Standards.

- - Adapted and paraphrased, edited, and supplemented, with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .

More Detailed Window/Door Design Requirements & Standards

Windows & Doors are manufactured & selected to meet specific building, site, & local code requirements for the following engineering or architectural areas:


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