Combating Hardware and Componentry Corrosion
When it comes to the maintenance and performance of windows, doors and skylights, components must not be a weak link in any fenestration system
With the increase in unusual weather events in North America, it’s worth examining the toll that weathering can take on hardware regarding windows, doors and skylights. A typical example is hardware and componentry corrosion. Fortunately, industry tools pertaining to this subject can help.
AAMA 907
The “Voluntary Specification for Corrosion Resistant Coatings on Carbon Steel Components Used in Windows, Doors and Skylights,” also known as AAMA 907, was updated in 2023. The document addresses zinc plating, zinc plating of threaded fasteners, and nickel and chrome plating—the more common materials since the industry’s transition to meet new materiality, environmental and safety requirements.
One aspect of the new specification delves into the definition of “substantial substances,” or areas that are openly visible and exposed once a fenestration component is installed, when in open or closed positions. Another change involves the return of a critical table listing coating materials that address corrosion—something salt often exacerbates in coastal regions.
AAMA 902
An update of AAMA 902, Voluntary Specification for Sash Balances, is currently in the works. This specification provides the materials, testing and performance requirements for sash balances used in hung-type windows. The biggest concern is addressing the balance between outside air entry and the ease of use/force required to open or close the window. A large, heavy sash may require an equally high-performing balance system to meet the required operating force.
The most significant change to AAMA 902 was the addition of the term “Manually Applied Force Ratio,” or MAFR, which is the ratio of the force used to operate a sash compared to the weight of the sash. The lower the MAFR, the less force is required to operate the sash. The specification provides for five classes of balances. Balances with the lowest MAFR are Class 5 and balances with the highest MAFR are Class 1. Beyond the height of weatherstripping employed, corroded or damaged hardware can add friction to the assembly, hindering free operation. Therefore, sash balances must be of corrosion-resistant material.
AAMA 701/702
The “Performance Specification for Pile Weatherstrips (AAMA 701) and Polymer Weatherseals (AAMA 702),” known together as AAMA 701/702, establishes minimum performance requirements for pile weatherstrips and polymer weatherseals. It also addresses in-service requirements of fenestration products to maintain acceptable levels of installed air leakage, water tightness and operational forces.
A key part of the document addresses “weatherability,” or the ability of a weatherstrip to maintain its construction and performance integrity under the influence of ultraviolet light, heat and moisture. The standard also assists users in selecting types and sizes of pile weatherstrips and the grooves in which they are installed.
When it comes to the maintenance and performance of windows, doors and skylights, components must not be a weak link in any fenestration system. In the face of steady extreme weather, several details relating to corrosion and the damage it can cause should be explicitly considered to help level the playing field against Mother Nature.
