What weather protection performance can louvres provide?

Weather performance in architectural louvres refers to how effectively a louvre prevents rain and wind-driven moisture from entering a building while still allowing airflow. Louvre weatherability is typically assessed through independent laboratory testing (e.g. BSRIA), which measures the amount of water that penetrates the louvre under controlled wind speeds and rainfall conditions.

The most recognised performance benchmark is BS EN 13030, which classifies louvres from Class A (the highest level of rain defence) through to Class D.

· Class A rain defence louvres provide excellent protection with minimal water penetration, even under high wind pressures.

· Other weather louvres may prioritise airflow over rain defence, offering lower penetration resistance but higher free area.

Weather protection is influenced by factors such as blade geometry, blade pitch, blade orientation, drainage paths, and the aerodynamic behaviour of the profile. The use and position of rear-mounted mesh can also significantly affect weather performance, often increasing resistance and altering the airflow path. High-performance rain defence louvres frequently incorporate more complex blade designs—and may orient blades vertically—to improve water separation, collection, and discharge.

At Solinear, our Aquarius X-LINE louvre profiles are engineered to provide robust weather protection while maintaining efficient airflow and architectural quality. We support design teams in selecting the right balance between airflow, free area, and rain defence performance to suit plant requirements, façade integration, and environmental exposure.

For more detail on the factors that influence rain defence performance, see “What affects the weather performance of a louvre?”