Louvers protect openings from rainfall, but certain louvers fulfill separate requirements. Learn more about four types of louver rain protection on the MCDLG Newsstand.
Louvers are versatile. Their unique design has many uses for building design, but their primary purpose is protection. In HVAC, louvers protect intake and exhaust points from water damage. It is important to keep these openings dry throughout the year.
Louvers are often divided into four types of rain protection: non-drainable, drainable, severe weather, and hurricane.
Louvers may share characteristics with louvers from other types. For example, a louver built for severe weather will have the same drainable features as a standard drainable louver. Hurricane louvers will also have these features, so that the louver can safely reject incoming rainwater. The difference between louver types comes down to testing.
All testing for louvers is conducted in accordance with AMCA’s standards for louvers. These standards include AMCA 500-L, AMCA 540, and AMCA 550. AMCA 500-L contains several testing standards for louvers, including a louver’s air performance.
For this article, we will focus on two characteristics:
Non-drainable louvers have no drainable features, as the name implies. They can still reject light rain, but they have no means to quickly evacuate the water that collects on their blades.
If the rain picks up even slightly, then you can run the risk of water splashing back into the louver. While they don’t provide much protection, they also have a negligible effect on the intake air stream.
Drainable louvers are commonly rated for water penetration only. Their main function is providing a pathway for rain to leave the louver quickly, and to minimize backsplash through the louver. While they carry the same drain features, they are considered a lower level of protection than a louver with a wind driven rain rating.
They can still protect an opening from rain, but they aren’t tested for severe weather. You can use drainable or non-drainable louvers in areas that are protected from rain, or in locations where rainfall won’t be an issue.
Severe weather is accompanied by high winds and heavy rainfall. That is why louvers with wind driven rain ratings are listed as severe weather louvers. These louvers were tested under intense weather conditions, where wind will blow rainwater straight through a standard drainable louver.
The test data will differ from louver to louver, but the presence of the data on the submittal signifies the louver’s capabilities as a severe weather louver. Severe weather louvers should be installed in locations that will be exposed to wind and rain.
In many instances, severe weather louvers will be called out as a requirement.
Hurricane louvers protect against extreme weather events, but they are tested specifically for hurricanes. These louvers are tested in accordance with AMCA 540 and 550, as well as Miami-Dade standards. They are tested against the rain and wind conditions that accompany a Category 1 hurricane, including debris impact resistance.
Hurricane louvers are always called out in the specifications, as required by local codes and standards. They should only be used to meet these requirements. If the application does not call for these protections, then use a severe weather louver.
It may seem obvious to choose the best louver rain protection for every opening in your building, but that isn’t the case. There will be other factors to consider, like how the louver affects airflow. You also need to think about the installation area.
Hurricane louvers are often larger and heavier than other louver types. The same-sized hurricane louver may not fit inside the intended opening, or it may need additional structural support. The same will be true for certain severe weather louvers.
These four louver types are designed to prevent water infiltration. While important, rain-resistant features may hinder the air stream as it passes through the louver’s free area. While a drainable louver may not be the best at blocking incoming rain, it may strike the balance you need for the application.
The important part is matching the right level of protection with each application. You will often find that certain louvers work better for different areas of your building.
You will need several kinds of louvers to complete your project. Manufacturers will often list a louver’s capabilities on their website, but the best way to know its ability is to check the submittal.
Look for the AMCA ratings seals for water penetration and wind driven rain. For hurricane louvers, look for the AMCA Listing label or the relevant Miami-Dade NOA.
To better understand hurricane louver standards, check out our article on AMCA 540 and 550, which covers the tests involved for AMCA listing and Miami-Dade.
Looking for louver rain protection? Consider severe weather louvers by Arrow United. We build every louver from the ground up to meet your project’s requirements. Browse our selection online. When you’re ready, contact Arrow United Industries. We are here to help.
For more on storm louvers, check out these Newsstand articles: