| Abstract | The use of heavy gases or gas mixtures in the cavity of sealed insulating glass (IG) units instead of air presents a challenge to the glazing industry and researchers to develop test procedures to assess the durability of the units and to determine the gas concentration inside the cavity. The main issue is to obtain gas samples at different time spans from the same unit without affecting the integrity of the edge seal.A laboratory test method to determine argon gas concentration in IG units was developed. The method is based on the use of gas chromatographic techniques. Oxygen, argon, and nitrogen are separated at subambient temperature (-30'C). Gas sampling was possible by means of a self healing plug made of a thermoplastic rubber and commercially available at a very low cost.A large number of10 units filled with an argon/air mixture were fitted with the special plug and tested for the durability of the edge seal according to the CANICGSB 12.8, Insulating Glass Units, standard (CGSB 1990). Test results showed that all the units tested contained less argon than the amount of 95% or higher claimed by the manufacturers at the time of assembly. Most of the tested units retained the argon gas, allowing for normal gas loss due to gas diffusion through the edge seal which varies between 1% and 5%, following the accelerated aging, high humidity, and volatile (jogging) tests. The test procedure to determine argon gas concentration in IG units is being reviewed by Canadian and American standards organizations for use in the certification of IG units. |
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