Need tips on louver design? Here are few pointers from the MCDLG Newsstand. Learn to design louvers that meet requirements with this article.
Louvers are simple, but designing a louver can be difficult. Each louver serves a particular purpose in the building, whether it’s protecting a ventilation point, blocking sunlight through an opening, or just adding a touch of style. Here are things to look for when designing a louver for your next project.
Greater free area means there is more space for air to pass through the louver, which translates to greater system efficiency.
Your fans will draw less power to pull air through the louver. This space will increase with the louver’s size.
Louvers with more free area will have lower pressure drop, although this will depend on the louver’s design.
When designing HVAC louvers, you notice the increases aren’t exactly uniform with the size.
This is because louvers will receive additional blades as their height increases. Manufacturers will determine the number of louver blades.
Manufacturers add blades to the louver to maintain a minimum spacing between each blade, typically determined by the height of each blade plus additional space.
While the exact measurement isn’t uniform between sizes, louvers will maintain a set percentage of total free area across its face. This percentage will help you gauge the free area of the louver at any size.
Blades make the louver. A drainable louver will always have drainable blades. Severe weather louvers will use drain troughs and various catches along the surface of the blade. The blades help determine the louver’s purpose in your building. The contours and features along the blade are part of its profile.
Louvers designed for airflow will have a flat profile when compared to a severe weather louver with several blade features. Air passes over the louver’s blades as it moves through the free area. Features along the blade profile help capture and reject water in the airstream, but they can also increase the louver’s pressure drop.
The key to louver design is meeting your requirements first. If your project needs a hurricane louver, then you will need a louver built and tested for hurricane scenarios. The specifications will detail the exact louver requirements, including any required tests.
Depending on the type of spec, you may also have required performance data for the louver. You can compare this data against the louver’s submittal to help determine if a louver is right for your project. Once that is done, you can look for ways to improve air performance.
Options and accessories can help fill in gaps in your louver’s design. Backsplash is a common issue with drainable louvers. It occurs when excess rainwater collects on the sill faster than the louver can drain it out through the face.
The excess rainwater can splash through the back of the louver into the interior of the building. It is important to avoid backsplash since water damage can damage your HVAC system and negatively impact air quality.
The solution to backsplash is a drain pan, an optional part that sits underneath the sill of the louver. Drain pans have a back plate that covers the bottom area of the louver so that the water can’t splash back into the louver. They also have a sloped lip along the face side of the pan to aid with draining water.
These optional parts are excellent for louvers that are expected to reject heavy rainfall.
That is why all hurricane louvers and many severe weather louvers will come with a drain pan as a standard feature. This is just one option available to louvers. Insect and bird screens can provide a barrier for unwanted guests that might try to get into your building through the louver’s free area. Read more about louver options here.
Finishes can provide a little extra help with performance, but their primary goal is adding color to your louvers. Your project will be more than codes and requirements. A project with a cohesive style will help occupants feel at ease.
More protection isn’t always better. For example, you may have a project that requires louvers that block wind driven rain.
Hurricane louvers provide the most protection against rainfall, so that would be the best option. Right? The better option is a wind driven rain louver. With louver selection, choose the louvers that meet the requirements.
The louver should always match the needs of the application first. Don’t overprotect. Protective features like drain catches are good for preventing water infiltration, but they will increase pressure drop as air flows through the louver. This makes it harder for your system to pass air through the louver.
Choose louvers that meet the project’s requirements. From there, you can design the louver to better suit the application. Check the louver’s pressure drop data to determine the louver’s overall air performance. You should design with balance in mind, between the protection and efficient airflow for the ventilation point.
Louvers are an important part of your building. Make sure each louver works in its intended application. Check the louver’s submittal and review its performance data.
Looking to add louvers to your next project? Consider adding stationary louvers from Arrow United Industries. We offer a wide range of louver types and models to help meet your requirements. And we build everything in our shop, giving you the freedom to design louvers that fit your project.
Visit us online to browse our full louver catalog.