What is the net free air in square inches of a 12" X 12" metal louver opening?

To determine the net free air of a 12" x 12" metal louver opening, it's essential to understand how net free area is calculated, particularly in the context of louvers and ventilation systems. The net free area is essentially the effective open area that allows for air passage, accounting for any obstructions within the louver itself.

For a 12" x 12" louver, the total opening area can be calculated simply by multiplying the width and height, resulting in 144 square inches (12" x 12"). However, this value represents the gross area, not the net free area, which usually requires adjustment based on the design of the louver, such as blade spacing and the angle of the blades.

Typically, metal louvers have a net free area factor ranging from about 0.40 to 0.75 of the total area, depending on the specific design and construction characteristics. For many standard installations, an average net free area factor is often estimated around 0.75.

Applying this factor to the total area, we can perform the calculation as follows:

Net free area = Total area x Net free area factor

Net free area = 144 square inches x 0.75

Net free