Proof of Concept: Testing for Long-Lasting Hardware Includes a Little Torture

By Glenn Ferris

No less important than glass and framing to the functionality and durability of a door or window unit is its operating hardware: sash balances, multi-bar hinges, door hinges, locks, rotary operators and roller assemblies. If a product is to be certified under the code-mandated North American Fenestration Standard (NAFS), these components must also be verified through testing, meeting AAMA hardware standards, which typically reference ASTM test methods or specifications listed in NAFS. These standards establish confidence in a product’s ability to deliver long-term operating functionality by applying test forces that simulate actual use and accelerated ambient conditions that simulate an installed environment. Actual testing must be done by an AAMA-accredited, full-service independent laboratory or an AAMA-approved component laboratory. Qualified components are recognized either by listing on the AAMA Verified Components List (VCL), an FGIA program, or by a bona fide laboratory test report.

In addition to functionality testing specific to the hardware type, all steel hardware items (other than stainless steel) must meet the freshly updated AAMA 907, Voluntary Specification for Corrosion Resistant Coatings on Carbon Steel Components Used in Windows, Doors and Skylights, which provides a standard method for evaluating adhesion and corrosion resistance of coatings for carbon steel fenestration hardware components.

For metallic coatings, the AAMA 907 specification requires application of any of the appropriate simple, qualitative test methods described in ASTM B571, Standard Practice for Qualitative Adhesion Testing of Metallic Coatings. The end use of the coated article or its method of fabrication will suggest the technique that best represents functional requirements.

For nonmetallic coatings, the adhesion of the coating is examined in accordance with Method B of ASTM D3359, Standard Test Methods for Rating Adhesion by Tape Test, as used in laboratory or shop environments for films up to 125μm [5 mils] thick. Method A is similar but is intended for use in the field. Test method B assesses adhesion by applying and removing pressure-sensitive tape over cuts made in the film and rapidly removing the free end of the tape at about a 180° angle. To pass the test, the coating must achieve a rating of 3B or better as defined in the standard.

Corrosion Resistance

The following coatings are acceptable if they comply with the indicated specification.
• Zinc plating: ASTM B633, Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel Type II;
• Zinc plating of threaded fasteners: ASTM F1941, Standard Specification for Electrodeposited Coatings on Mechanical Fasteners, Inch and Metric, Classification Code 8A (minimum); and
• Nickel and chrome plating: ASTM B456, Standard Specification for Electrodeposited Coatings of Copper Plus Nickel Plus Chromium and Nickel Plus Chromium, SC3 (minimum).

For coatings other than these, the recommended test method is described in ASTM B117, Standard Practice for Operating Salt Spray (Fog) Apparatus. Parts must withstand exposure for 300 hours in a sealed test chamber without evidence of corrosion. For galvanic corrosion, ASTM G82-98, Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion Performance, is recommended for materials known to have galvanic reaction potential.

For certification and code approval, meeting every current hardware component performance specification is as much a quality control requirement as passing structural load tests for the entire product. Guidelines for the conduct of the AAMA Components Verification Program for hardware are published in Component Verification Program Manual CVPM-H.

Glenn Ferris is fenestration standards specialist for the Fenestration and Glazing Industry Alliance (FGIA).

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DWM Magazine

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