Water tightness is a measure of a window or door’s ability to prevent water penetration when subjected to specific levels of wind-driven rain. It’s not about submerging the product in water; it’s about its performance under simulated storm conditions. This performance is closely related to another key metric: wind resistance class<\/strong>.<\/p>\n\n\n\n This performance is tested in a laboratory according to strict international standards, such as the European Standard EN 12208<\/strong> or American standards like ASTM E331<\/strong><\/a> and ASTM E547<\/a><\/strong>. During the test, the unit is mounted in a test chamber and subjected to increasing air pressure differences (simulating wind) on one side, while a spray rack simulates heavy rainfall on the other.<\/p>\n\n\n\n The European standard EN 12208 defines water tightness using classes, typically from Class 1A<\/strong> (lowest resistance) to Class 9A<\/strong> (highest resistance). The classification is based on the pressure difference (in Pascals – Pa) the product can withstand without allowing any water to pass through to the interior side<\/em>.<\/p>
\n\n\n\nThe Classification System: <\/strong>Understanding the Code (EU vs. US)<\/em><\/h2>\n\n\n\n