Which statement correctly describes the minimum angle for stationary louver blades?

Which statement correctly describes the minimum angle for stationary louver blades?

• A. 30 degrees
• B. 45 degrees
• C. 60 degrees
• D. 15 degrees

Answer: (B)

The angle of stationary louver blades determines how well rain water is shed and how easily air can flow through the opening. When blades are fixed, a steeper slope helps rain be deflected away rather than enter the vent, while still allowing ventilation. A minimum of 45 degrees provides a reliable balance: it deflects precipitation and resists wind-driven water without excessively hindering airflow. Shallower angles, like 30 or 15 degrees, are more prone to allowing water into the opening, whereas a much steeper angle, such as 60 degrees, reduces airflow more than necessary. So, the recommended minimum is 45 degrees.

The angle of stationary louver blades determines how well rain water is shed and how easily air can flow through the opening. When blades are fixed, a steeper slope helps rain be deflected away rather than enter the vent, while still allowing ventilation. A minimum of 45 degrees provides a reliable balance: it deflects precipitation and resists wind-driven water without excessively hindering airflow. Shallower angles, like 30 or 15 degrees, are more prone to allowing water into the opening, whereas a much steeper angle, such as 60 degrees, reduces airflow more than necessary. So, the recommended minimum is 45 degrees.