Glass Glossary

Chemical Fogging


Last Updated: December 4, 2023

Chemical fogging refers to the appearance of a fog-like substance inside an insulating glass (IG) unit. This can occur when materials used in insulating glass, such as sealants, grilles, spacer systems, desiccant, and more, produce a fog within the unit. Chemical fogging can obstruct visibility and detract from the aesthetic appeal of the glass, impacting the overall performance and appearance of windows and doors.

To screen for the potential of chemical fogging in IG units, ASTM International established a test method known as E2189 (Standard Test Method for Testing Resistance to Fogging in Insulating Glass Units). This test aims to determine the fogging resistance of IG by exposing them to specific conditions.

Recognizing the importance of minimizing chemical fogging in its products, Cardinal has developed its own more rigorous version of the ASTM E2189 test. Cardinal’s chemical fog test exposes units to higher temperatures and utilizes a more demanding inspection criteria. This test is approximately four times more demanding than the ASTM test, ensuring that Cardinal’s insulating glass maintains clear visibility and provides a reliable, high-quality performance. By employing this testing method, Cardinal ensures that its IG is more resistant to chemical fogging, offering better long-term performance and visual clarity.