Understanding Wind Driven Rain Louvers

For locations subject to severe weather or where water infiltration must be minimized, wind-driven rain louvers are an easy choice. Designed to drop water out of the air as it passes through the louver and to drain the water away, wind-driven rain louvers are exceptional at handling streams of air with entrained water.

How Do Wind-Driven Rain Louvers Work?

Wind-driven rain louvers appear similar to standard louvers but are designed to effectively prevent water penetration during storms. When standard drainable louvers are not up to the task, wind-driven rain louvers are the solution to keeping water out.

Purpose of Wind-Driven Rain Louvers

Wind-driven rain louvers will prevent rain infiltration, under certain conditions, during severe weather. With these louvers, filters stay dryer and less interior water damage and mold growth will occur. Interiors of non-ducted and non-drained applications will also stay dry and protected. Due to the ability of wind-driven rain louvers to prevent water infiltration, higher intake velocities and smaller louvers can be used which can be very helpful in some applications.

Purpose of Wind-Driven Rain Louvers

Water Penetration Rating

AMCA Standard 500-L is used to certify the performance of wind-driven rain louvers. Third-party testing allows wind-driven rain louvers from one brand to be compared to another more easily. Two tests are commonly used: the “still air” water penetration test and the wind-driven rain test.

During the still air water test, the louver is tested to find the beginning velocity where water will penetrate into the louver. The air speed is increased to a maximum of 1,250 fpm of free area of the louver. During the still air test, the louver is tested without wind, which simulates rainfall without wind. While this test provides a good starting point for louver comparison, it should not be the sole basis for design selection.

The wind-driven rain test provides a more aggressive test for challenging wind-driven rain louvers. Instead of still air water, a machine is used to entrain water and direct the airflow at the louver. The test provides a rejection effectiveness class to compare against other louvers:

  • A: 99% to 100%

  • B: 95% to 98.9%

  • C: 80% to 94.9%

  • D: Below 80% (standard drainable louvers)

Each rating will also list the conditions for that rating. Two rainfall rates are used: 3 inches of rain per hour, at a velocity of 29 MPH, and 8 inches of rain per hour at a velocity of 50 MPH. The louver will then get a classification rating based on the test conditions and various free area velocities. Along with the free area and pressure drop data, this information can be used to compare the performance of different louvers and to select the best louver for a specific application.

Pressure Drop Through the Louver

Blade spacing is typically tighter in a wind-driven rain louver with the blades also having a more sophisticated profile. This tighter blade spacing helps to reduce the water penetration into the louver but can also reduce the free area of the louver. The reduced free area and unique blade profiles tend to increase the pressure drop for a given airflow and louver area.

Wind-Driven Rain Louver Applications

Locations susceptible to severe weather conditions or that aim to reduce the risk of water infiltration should consider utilizing wind-driven louvers.

When Are They Used?

Intake systems that need to minimize water infiltration or that must operate during severe weather will need wind-driven rain louvers. These intake systems will often encounter situations that would cause water to enter the building. Water infiltration can cause serious damage, especially if it occurs repeatedly. The unique design of wind-driven rain louvers prevents rain infiltration, to keep the building safe.

Sizes and Materials

Most wind-driven rain louvers are made from aluminum extrusions. Designed to blend in with the aesthetic of any building project, AWV louvers can be painted in any of 25 standard colors or matched to a custom color.

American Warming and Ventilating (AWV) Wind-Driven Rain Louvers

American Warming and Ventilating (AWV) offers a wide selection of wind-driven rain louvers in various frame sizes, with either exposed or hidden mullions. Our wind-driven rain louvers are designed to meet any project need in an energy and cost-efficient manner. Our LE line of wind-driven rain louvers provides an architectural solution that also provides the highest AMCA class A rating against the damaging effects of rain penetration.

The LE series of louvers offers both horizontal and vertical blade orientations. Available in aluminum in any of AWV’s 25 standard finishes, wind-driven rain louvers are built to last and work well with any project. The wind-driven rain louvers come in depths ranging from 2” to 7” and are all designed to optimize performance and pressure drop. AWV wind-driven rain louvers have the look and functionality that you desire. Consider your options, then contact us today for more information.

The Benefits of AWV’s Wind-Driven Rain Louvers

The Benefits of AWV’s Wind-Driven Rain Louvers

AWV wind-driven rain louvers provide best in class protection against the most severe weather events. Exceptional engineering and design allows AWV to produce wind-driven rain louvers that maximize airflow while minimizing water infiltration. In addition to exceptional performance, AWV frequently works with architects and engineers to create a louver that not only performs well, but also meets the aesthetic needs of the project. Whether through custom finishes, special shapes, or unique installation conditions, AWV helps architects to build lovers that stand out in their design.

AWV Options and Accessories

AWV offers an expansive selection of options and accessories to simplify installation and provide the functionality required:

  • Customizable size depending on application

  • Options to meet water penetration rate requirements

  • Vertical or horizontal designs

  • Filters and filter racks

  • Bird and insect screens

  • Hinged panels and locking hardware

  • Louver sleeves

  • Glazing tabs for installation into glazed systems

  • Flanged frames

  • Extended sills

Why Choose AWV Wind-Driven Rain Louvers?

AWV brings decades of experience to designing their wind-driven rain louvers. With exceptional quality, consistency, and reliability, AWV makes the wind-driven rain louver you can trust. To learn more about selecting the right louver for your application, reach out to our louver experts today!