Integrated Standard Targets
the Performance of Windows and Doors

Special Advertising Supplement Provided by Marvin Windows and Doors

Continuing Education

Learning Objective:
After reading this article, you will be able to:

1. Explain the integrated standard and how it came about.

2. Describe the performance criteria for windows and doors.

3. List the five performance classes for windows and doors.

4. Describe the specification for window and door materials.

The subject "industry standards" often raises less enthusiasm than would a discussion concerning the design of a new building. Yet, that knowledge can protect against any product failures that may result from improper product selection for specific applications. And, a familiarity with industry standards can help create innovative design.

For fenestration products, a significant advancement occurred with the merger of two nationally recognized standards that brought uniform performance testing requirements to the entire window and door industry. In 1997 specifications for aluminum and vinyl window and door systems as found in the ANSI/ AAMA 101-93 standard were combined with specifications for wood windows and doors, as found in the NWWDA I.S. 2-93. The resulting document is entitled "Voluntary Specifications for Aluminum, Vinyl (PVC), and Wood Windows and Glass Doors". (ANSI - American National Standards Institute; AAMA - American Architectural Manufacturers Association; NWWDA - National Wood Window and Door Association, which has been recently changed to WDMA, Wood and Door Manufacturers Association; ASTM - American Society of Testing Materials.)

The new specifications implement changes, but some study of the provisions is necessary to fully grasp the new implications. In light of that, this summary offers a brief examination of the voluntary specifications, developed to aid manufacturers, architects, and specifiers in rating, comparing and selecting products.

The 1997 Voluntary Specifications

This standard of specifications is predominately performance based. The testing and performance of the total product is emphasized. Performance ratings are expressed as design pressures (DP) called "grade levels." This is a measurement of the amount of pressure, expressed in pounds per square foot, that a window or door is designed to withstand when closed and locked. Samples are actually tested to 1.5 times the rated design pressure, providing an ample safety factor. Primary performance factors rated are structural strength, water resistance, air infiltration, forced entry, and operating force where applicable.

In addition to DP/Grade rating, size of the test specimen is regulated creating a dual evaluation system. This is a significant change for some products in that past standards allowed the size to be selected by the manufacturer. By selecting a small test sample a manufacturer could claim higher performance. Unless the architect specifically requested this information, he or she might not make a fair comparison of products or receive a proper product for the application, according to Jim Krahn, Marvin's Advanced Research Manager. Under the new standard, the prescribed minimum size or larger must be tested to claim specific ratings. These minimum sizes are different dependent on product type and performance class.

Terminology

Facile application depends on an understanding of the specifications' terminology. Window and door products are designated by a four-part code, as seen below.

The product type list includes 20 products.

Windows and door products are classified into five performance classes.

Products must be tested to the minimum "gateway" values shown in the following chart. Products may also be tested and rated to higher performance levels for use in areas where code or weather conditions require higher performance. Note that water resistance testing increases as the DP/Grade levels increase. The process to establish these needed DP/Grade ratings is quite complex varying by geographic location, height of the building, building shape, location of the windows or doors in the wall, occupancy, and other factors.

The higher a DP/Grade number, the better the structural performance. As a frame of reference: DP 40 means that a window is tested to 60 pounds per square foot (PSF) equal to a 155 mph wind and must withstand water penetration under conditions equal to eight inches of rain per hour driven by 50 mph winds.

In addition, the specifications prescribe specific requirements appropriate to each type of window or door. Specimens are tested for hardware loading, deflections under concentrated and torsional loads, deglazing, and life-cycle testing for architectural rated products.

The standard also responds to changes in the nationally recognized wind speed map, and a different calculation needed to translate a velocity pressure to a design pressure.

In the Test Chambers

A test specimen from each window and door product line is rigorously tested against the four primary performance requirements. These tests must be performed in an accredited independent or calibrated in-house laboratory under the supervision of an independent observer.The four mandatory primary performance requirements include:

• WATER - resistance to water penetration, according to ASTM E 547 or ASTM E 331.
  
• WIND - structural adequacy to withstand wind loads, according to ASTM E 330.
  
• AIR - resistance to air infiltration, according to ASTM E 283.
  
• FORCED ENTRY - resistance to forced entry, according to ASTM F 588 and F 842.

Operating force is a mandatory test for certain products, such as sliding windows and doors.

Optional tests establish acoustical performance and thermal rating in accordance with NFRC 100 and condensation ratings according to AAMA 1503.

The tests are performed with the test specimen mounted to a test chamber (drawings above illustrate ASTM specifications). Sliding windows are first tested for operating force to assure that they are below the required forces. Then the chamber is pressurized to force air through the specimen. The air is measured in cubic feet per minute and applied to the size of the window, resulting in a cubic feet per minute per square foot of product rating. The chamber pressure is increased to the appropriate level to test for water penetration. Water is simultaneously applied to the exterior surface of the specimen simulating rain at eight inches per hour. No water may penetrate the interior surface of the test specimen. Last, but not least, the pressure is increased to achieve the desired DP/Grade rating. A separate identical unit is normally tested for forced entry.

Materials and Components

Materials used for structural components made of aluminum, vinyl, and wood must comply with prescriptive specifications that assure proper aluminum alloys, vinyl compounds, and wood components are being used. Exterior wood components must be preservative-treated in compliance with WDMA I.S.4. In addition, prescriptive requirements are established for protective coatings and finishes used on metal components such as hardware and fasteners.

As mentioned in the voluntary specifications, requirements are straightforward:

• Aluminum: Aluminum, where used as a sash, frame, or other structural member, shall be of commercial quality and of proper alloy, for window and glass door construction, free from defects impairing strength and/or durability.
• Vinyl: Rigid PVC extrusion where used as a sash, frame, or other structural member, shall comply with AAMA 303.
• Wood: Wood parts, where used, shall be wood or wood composites that have been kiln-dried to a moisture content of no greater than twelve percent at the time of fabrication.
  

Optional Performance Grades

It's important to note that the Voluntary Specifications measure minimal performance compliance. For use in areas where severe weather conditions or strong winds are common, optional performance grades need to be considered. These criteria call for higher uniform load structural test pressures as well as higher water resistance test pressures.

Specifying Windows and Doors

It can be a complex task to establish appropriate performance levels. To aid in the process most jurisdictions have adopted building codes on a state or local level. These codes help guide the architect in selecting products that are appropriate for the job conditions.

With the standards in hand, specification can be straightforward. Take, for example, the specifications for single, double, and triple hung windows. Such windows are defined as vertically operating windows in which the sash weight is offset by a counterbalancing mechanism mounted in the window. One or more locking devices are furnished to secure the sash in the closed position.

Yet, more complex nuances are possible. As Krahn says, "Let's say an architect is looking for a DP40 window. A DP40 window is tested to 60 pounds, which is the same as a 155 mph wind. A small residential, double hung window would fit this specification. So would a light commercial window, except that that light commercial window could be a larger specimen. If you took the commercial DP40 window and you built it in the smaller residential size, it would probably test to DP80. Because all the members are heavier and stronger."

Krahn continues: "When an architect is looking at a project, the decision has to be made as to window size. If the windows are all very small, then the architect has some options. He or she can choose residential or light commercial. But if there are a number of large windows for the project, especially if those windows are larger than are typically used for residential, then the architect has to understand the standards in order to identify differences between the residential and commercial window criteria."

Marvin's products are designed to meet-or exceed-the voluntary specifications discussed in this compendium. In fact, the company is quite active in the process of establishing standards for the window and door industry. Marvin's Manager of Advanced Research is currently the chairman of the Performance Standards and Certification Policy Committee of the Window and Door Manufacturer Association.

Marvin offers over 11,000 different standard sizes and shapes and encourages custom designs. Unlike other manufacturers, Marvin does not warehouse an inventory of finished products. Instead, the company mills and stores component pieces and then builds every window and door to fill a specific order. This made for you philosophy makes it possible for Marvin to offer a wide selection of shapes, styles, sizes and options. Also this flexibility makes the company receptive to challenging, one-of-a-kind special projects.

Each new product line is subjected to the rigorous tests described here. The new Clad Ultimate Double Hung window is rated up to DP40 on most sizes, meaning that it met or exceeded levels specified for air, water, and structural performance. In addition, the Clad Ultimate Double Hung offers high energy performance through the use of Low E II glass with argon. Ease of operation is also highlighted through the use of an exclusive sash tracking and locking system. The system offers smoother operation with almost effortless opening, closing, and tilting.

Questions:

1. What is the significance of the integrated standard for windows and doors?

2. What are the performance criteria windows and doors must meet?

3. How are the performance criteria measured?

4. What are the requirements for window and door materials?

5. What are the five performance classes for windows and doors and how does this affect specifying products?