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Use our CFM calculators and charts to determine how many vents you need for your project.

AV Diameters

Enter the length and width (in feet) or total square footage of your building in the fields below to determine how many vents are required based on the 1/150 or 1/300 Rule. This calculator is for the EXHAUST HALF ONLY. If an intake ventilator is needed, just double the amount of vents. For example, if 2 AV-14 are needed and inlet vents are needed, then an additional 2 PV-14 vents would be required

PV Diameters

UV Diameters

AF Diameters

KV Diameters

To earn a UL certification, the entire manufacturing process, from material selection to product design, has to meet strict guidelines and pass rigorous tests. All testing for AVP's Keepa Vent, Round Back Vent, and Universal Vent were conducted by UL at their testing facilities in Northbrook, IL. The testing protocol was to pass the requirements for the Florida Building Code and the Texas Department of Insurance. The test conducted was the E330 pressure test. 
This test reconstructs simulated high wind environments to examine the performance of the roof vents under extreme conditions up to 230 MPH.

Round Back Static Roof Vent– A low profile Round Back Static Roof Vent stands out among other static roof vents because this static roof ventilator is made of aluminum and not galvanized. 



Other galvanized static ventilators rust. You can see those static vents creating rust streaks down people’s roofs. Our Round Back Static Roof Vent will not rust, it always looks like new. A Round Back Static Roof Vent installed years ago looks virtually new today. Low profile and an effective static ventilator, the Round Back Static Roof Ventilator keeps out rain and snow and helps to reduce attic temperature in the summer and moisture in the winter. Roof vents and attic vents have many engineering terms used to describe them. One of these terms is a static vent. One may ask the question, why that name? The answer lies in the definition of the word “static”, which is stationary or not moving. Static vents are very popular with architects, engineers and roofers due to the fact that they have no moving parts. Needless to say anything that has no moving parts to wear out will last a long time. This is true in the case of a roof vent or static vent that has no moving parts, the static vent will last the life of the roof. The only time a static vent has to be replaced will be when a there is a re-roofing. The only reason it will need to be replaced is because the flange that gets nailed or screwed to the roof becomes unusable when removed. Between the nails or screws and the roofing sealant, the flange gets all bent up and distorted when removed. Since the cost is so low for a static vent, it is much easier and economical to just buy a new one and replace the old static vent. Generally speaking all static vents are good vents. All they are is an umbrella over a hole. The challenge has been to make them appealing to the eye and as low a price as possible. The Round Back Vent is an excellent vent for preventing weather such as rain and snow from entering the attic while allowing for passive exhaust to the outside. The round design is aerodynamic, because it is round and deflects the wind instead of blocking it. The round design is also very appealing to the eye and the powder coating option further reduces the profile of the vent.

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