Penthouses - Roof Louvers for HVAC

Penthouses - Roof Louvers for HVAC

Need roof louvers? Your project may have ventilation points on a flat rooftop. Protect these points with penthouse louvers. Learn more on the Newsstand.

Protecting Rooftop Openings

Ventilation points are common features along the walls of a building. These places are typically the intake and exhaust points of the building’s HVAC system. Louvers will protect these openings from harmful elements, like rainwater and debris, while allowing air through the opening.

Penthouse with a sloped roof and mitered corners

What if the ventilation point is on the roof of the building? Intake and exhaust points are common roof features. We know this method as gravity ventilation. Mounting a standard louver vertically would allow rainwater to pass through its free area and into the ductwork below. It won’t work in these instances. You need a roof louver, also known as a penthouse, to keep your ductwork dry.

 

Penthouse Construction and Customization

A penthouse is an assembly comprising four panels and a roof. Standard penthouses are highly customizable, providing options for the four panel walls, the roof, and the corners of the panels. You can customize the four panels to suit the needs of the application. You can choose louvered panels on each side of the penthouse to maximize airflow into the opening. Or you can have louvered panels on opposite sides, if you need the ventilation point for intake and exhaust flow.

A penthouse covers HVAC equipment, concealing it from view.

For standard penthouses, panels can be any size you need to accommodate any roof opening. The penthouse should be large enough to cover the opening. Manufacturers may also offer their other louver models as panel options for the penthouse. 

In these instances, you can choose drainable louvers to prevent rain from infiltrating the penthouse. When equipped with the right panels, penthouses are roof louvers that protect ventilation points on the roof. You can also choose severe weather louvers for guarding against wind driven rain.

An AMCA-approved laboratory can test and rate the louvers for severe weather, but the penthouse assembly will lack this rating. This is an important distinction to make when considering hurricane-rated penthouses. Adding hurricane louvers to the penthouse will not make it a “hurricane penthouse”. There are additional aspects to consider when meeting hurricane requirements. The Florida Building Code must approve the full assembly for hurricanes. The same is true for AMCA's standards for hurricane louvers.


A penthouse with an access door

You can also add a hatch on one side to provide access to the interior of the penthouse. You can also choose a panel with a glass viewport, for applications that require you to see into the penthouse. Doors and viewports are useful options for maintaining a damper installed in the roof opening. Certain penthouses will come with a curb attachment that has an access door. Be sure to check the penthouse submittal to see your available options.

For more on louvers and dampers, check out our other Newsstand articles:

 

Corners and Roofs

You can choose to post caps or miter welds for the penthouse corners, depending on the look you want. For mitered corners, the blades from each panel will come together at the corner. This creates a continuous look from panel to panel. The manufacturer assembles mitered corner pieces at the factory and installers join them to the louver panel during the installation process.

Example of penthouse corners, miter weld and post

Post corners have a metal cover that creates a discreet corner piece between the panels. The post corner accepts the louver blades from the adjoining panels. This design provides support for the louver blades while creating a sturdy, square look to the finished penthouse.

Mitered corners have similar supports in place for the louver blades. Metal angles typically sit behind the blades to reinforce mitered corners. Both corner types provide support for the panels.

Photo of a post-cornered penthouse

This is an example of a penthouse with post corners. 

The roof of the penthouse can be flat or sloped to deflect rainwater. The exact angle and design of the roof may differ between penthouse models, but manufacturers will often allow full customization of the roof to fit your specifications. Once installed, the penthouse will sit over a ventilation opening on the roof to protect the opening from rainfall and other unwanted debris.

 

Curbs and Throats

Typically, manufacturers include curb and throat attachments when the penthouse will have a damper for the opening. The curb is a platform that is attached to the opening receiving the penthouse. The curb can receive an access door on one side, so that technicians can easily access the damper inside the penthouse.

An rooftop opening and a penthouse

The curb piece is mounted to the rooftop opening. The penthouse sits on top of the curb.

The throat is a duct assembly that joins the penthouse curb with the duct inside the opening. This connects the penthouse directly to the ductwork. It is common to place a control damper inside the throat, so that operators can control airflow at the ventilation point.

Smoke Evacuation

People commonly use penthouses for smoke evacuation in elevator shafts. Manufacturers will call these “elevator vents” or “smoke evacuation penthouses”. During a fire event, smoke will gather inside elevator shafts and rise into the upper floors of the building.

A UL-rated smoke damper in the smoke evacuation penthouse opens when smoke is detected in the elevator shaft. This provides an exhaust point for the buildup of smoke in the elevator shaft. You may also use a fan system to draw the smoke up to the exhaust point. The smoke evacuation penthouse provides a clear exit for smoke and noxious fumes.

Demonstration of a smoke evacuation penthouseThe elevator shaft on the left does not have a smoke evacuation penthouse. The smoke fills the upper floors, endangering occupants. The smoke evacuation penthouse provides an exhaust point for the smoke to leave the building.

Penthouses and Gravity Ventilation

Penthouses protect roof ventilation openings from the elements. When equipped with the right panels, the full assembly will work as a roof louver. The penthouse, as an intake louver, can allow for gravity ventilation by enabling air to flow naturally into the opening.

Keep fresh air flowing into your HVAC system while keeping rain and other harmful elements out. You can customize penthouses to fit the needs of your application.

Three penthouses

 

Starting a new HVAC project? Need louvers to protect your ventilation points? Arrow United Industries can help. We build louvers and penthouses for a variety of applications, from standard airflow louvers to severe weather and hurricane louvers. We can help you meet your project’s needs. Contact Arrow United today and let’s work together on your next project.

 

Have any experience with penthouse louvers? Tell us in the comments section. We want to hear from you!


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