JUNE 30TH, 2017 DEVELOPMENT OF STAINLESS STEEL BASED WARM EDGE SPACER SYSTEMS GERHARD REICHERT President of Glasslam and Polymer Extrusion Technology
HISTORY OF WARM EDGE SPACERS Invented together with insulating glass units in 1865, Thomas D. Stetson patented the use of insulating spacers or warm edge spacers. But the spacers and sealants used were too permeable and the IGU did not last long.
COLD EDGE SPACERS HELP SOLVE IGU DURABILITY BUT... From the 1960s until today, roll formed aluminum and steel spacers became popular for use with modern sealants and desiccants, to help make IGU last longer and be affordable. The problem was, even though metal spacers provide a perfect barrier against moisture vapor, they were of highly conductive material, losing energy through the IGU edge of glass and frame zones.
STAINLESS STEEL STEPS IN TO SAVE THE DAY Therm Conductivity 130 10-12 0 K - 150 K - 300 K Aluminum Stainless Only glass and metals are perfect moisture vapor and gas barriers above sea level. Stainless steel becomes a favored choice for spacer materials, having much lower conductivity than aluminum, and being much stronger at very thin thickness gauges.
STAINLESS STEEL OPTIMIZED THROUGH THICKNESS Energy flow through materials can be reduced by lessoning material conductivity, and by reducing the cross-sectional area of the same material for energy to flow through. Thin gauge stainless steel has been popularized and made affordable by the disposable razor blade industry. Now stainless steel spacers can take advantage of cost effective thicknesses down to 2 mil or 50 micron.
STAINLESS STEEL OPTIMIZED THROUGH RECIPE Once stainless steel has been chosen as a perfect metal vapor barrier with relative low conductivity, the conductivity of the stainless steel can be further optimized by compound, alloy, and recipe. Many warm edge spacer manufacturers started with stainless steel but have slowly progressed to lower conductivity versions.
STAINLESS STEEL OPTIMIZED THROUGH DESIGN Corrugation of stainless steel allows thinner gauges of stainless to be used with similar strength, further reducing conductivity. Lengthening the path of thin gauge stainless steel across the spacer width also helps reduce conductivity and energy flow.
STAINLESS STEEL OPTIMIZED THROUGH HYBRID SPACERS Many warm edge spacers today use a combination of insulating polymeric materials and strategically placed stainless steel on the back side only, for both quality secondary sealant adhesion and perfect vapor barrier performance. This maintains the perfect barrier qualities of stainless steel for optimum durability, while reducing its use for the entire spacer. The front of the spacer is an insulating polymeric bridge, reducing the stainless conductive path from two to one.
STAINLESS STEEL OPTIMIZED BY ALLOWING LESS SEALANT USE A perfect barrier against argon or moisture vapor transmission, and yet fully weather resistant on its own, stainless does not have to be covered up with sealant. A stainless steel backed spacer allows options of thermally breaking the secondary sealant mass, and only gunning sealant in to the corners at the glass and spacer interfaces.
STAINLESS STEEL SATISFIES ADHESION WITH ALL SECONDARY SEALANTS With using stainless steel on at least the back side of warm edge spacers, it secures the question about proper secondary sealant adhesion to spacers and helps prevent concern of any spacer displacement in to the vision area of IGU. It technically satisfies the long-term security and durability of IG systems for both residential and commercial use. Architects can believe in and specify spacer systems using stainless steel.
STAINLESS STEEL NOW AVAILABLE IN RIGID AND FLEXIBLE SPACER SYSTEMS The benefits of stainless steel for sealant savings, thermal improvements, sealant adhesion, and perfect barrier performance are available with numerous warm edge spacer systems. Three stainless spacer categories are: rigid single material, rigid hybrid, and flexible hybrid.
IGCC / IGMA SPACERS REVIEWED The reviewed spacer list has 17 stainless steel warm edge spacers: 1 Flexible hybrid stainless steel 4 Single material box/rigid stainless steel 4 U-Shaped hybrid stainless steel 8 Plastic hybrid stainless steel
AUTOMATION AVAILABLE FOR STAINLESS STEEL SPACER SYSTEMS Automated bending machines have been developed for most rigid stainless steel spacers whether single material or hybrid in nature. A few may require heated automated benders due to the polymer used. Automated flexible spacer application robots have been developed for flexible stainless steel spacers.
IGU INDUSTRY HAS CAST THEIR VOTE FOR STAINLESS STEEL Best in class warm edge spacer material for: SEALANT ADHESION GAS AND MOISTURE BARRIER THERMAL PERFORMANCE OVERALL DURABILITY IGU AUTOMATION
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