Volume 37, Issue 4, April 2002

Finsishing School
        New Specifications for Architectural Aluminum Finishes
by Steve Green

Architectural aluminum finishes are more than just "pretty colors." The finishes on architectural metal—whether anodized or painted—provide protection against weathering, abrasion, chemical damage and erosion. Often backed by extensive warranties, architectural aluminum finishes are considered important enough by the industry that proper use is specified by the American Architectural Manufacturers Association (AAMA). The specifications for finishes have recently been revised, as AAMA incorporated new technologies and products into its guidelines.

AAMA Standards
AAMA is an expert source of performance standards, product certification and educational programs for the fenestration industry. Nationally recognized AAMA standards and specifications establish a baseline of performance for new materials, provide quality assurance for buyers, specifiers and fabricators, and serve as a point of reference for national code organizations and local code officials. For more than 60 years, AAMA has developed standards that provide third-party validation of product performance and quality, but these standards are not static. AAMA certification standards are changing continuously as new products are developed and submitted for testing, and as new technology becomes the industry norm. One of the missions of AAMA is to help bring a wide variety of new, advanced materials and products to the marketplace by developing the specifications and test methods necessary to allow them to be evaluated fairly and comprehensively.

The "AAMA Certification" label on a product tells customers that the products conform to the ANSI/AAMA/ NWDA101/I.S.2 standard through independent laboratory testing and on-site inspection of the manufacturer's products. AAMA's Certification Program Verified Components List is a complete list of window and door component manufacturers that have submitted samples for testing and have been found to be in full compliance with the applicable specifications. The stringent AAMA industry standards not only define basic performance requirements for vinyl, wood and aluminum doors and windows, but also the standards for window and door components, such as extrusions, glass, sealants, finishes and hardware.

Finishes and Textures
In the last few years, AAMA has re-evaluated the performance designations for the durability of organic coatings on aluminum extrusions and panels used in high-quality aluminum windows and doors. This re-evaluation was the result of advances in aluminum coating technology.

AAMA previously identified "good" (AAMA 603) and "better," high-performance (AAMA 605) grades of coatings. These have been superceded by a new series of stringent standards that will allow architects, building owners and contractors to select and specify the appropriate performance level of factory spray-applied organic coatings for different job requirements.

New Designations
The first new AAMA designation—AAMA 2603—is intended primarily for interior coatings of at least 20 microns (0.8 mil) thickness and used in applications involving only limited ultraviolet (UV) exposure. This standard provides test methods and acceptance criteria for color uniformity, specular gloss, dry-film hardness, film adhesion, impact resistance, chemical resistance, corrosion resistance (under varying conditions of humidity and salt spray exposure) and weathering. Compliant systems include 70 percent Kynar, 50 percent Kynar and baked enamel. Kynar is a fluoropolymer possessing chemical resistance, imperviousness to UV rays, high-barrier properties, high purity and good mechanical and thermomechanical properties.

Designations AAMA 2604 and 2605 apply to coatings of at least 30 microns (1.2 mils) thickness and are intended primarily for commercial- and architectural-grade applications. Both utilize the same ASTM test methods and performance criteria to evaluate color uniformity, specular gloss, impact resistance and chemical resistance. They include additional test methods and acceptance criteria for abrasion, chemical resistance and weathering. Weathering tests evaluate color retention, chalk resistance, gloss retention and resistance to erosion after mandatory extended outdoor test exposure in a South Florida environment.

Chrome pretreatment is not allowed in some markets where concerns exist about the use of heavy metals. AAMA 2604 recognizes high-performance coatings that could include non-chrome pretreatment as a concession to environmental factors. AAMA 2605 addresses complete coatings systems based on chrome pretreatment, which is often necessary for the best long-term adhesion of the coating to the metal. AAMA 2605 also specifies superior quality coating formulations. This high-performance specification allows only the use of 70 percent PVDF coatings over a chromate conversion pretreatment. PVDF is "PolyVinyli-Dene Fluoride," the base resin for the longest life coating available.

The new AAMA designations definitely assist in the development of specifications for superior coatings for aluminum extrusions in the fenestration industry. Jeff Murphy, vice president of commercial and architectural sales and marketing for Linetec—a Wausau, Wis.-based architectural contract finisher—believes the new standards have benefited the industry immeasurably. "Clearly, we have raised the performance bar for top-end finishes," he said. As quality and durability are all pervasive concerns in the field of architecture, it is reassuring to know that strict standards are being applied to every detail of a project-right down to the finishing touches.

Steve Green is the director of sales and marketing for Tubelite Inc., a manufacturer of architectural aluminum storefronts, entrances and curtainwall products, based in Reed City, Mich.

USG