Air-to-Cloth Ratio Calculator
What is Air-to-Cloth Ratio?
The air-to-cloth ratio, describes how much dirty gas passes through a given surface area of filter.
The air-to-cloth ratio (or air-to-media ratio) is the amount of air (in cubic feet per minute, or CFM) flowing through each square foot of filter media in a baghouse. It’s a basic measurement of how hard the system is working to move air through the filters.
How to Use This Calculator
⦿ Enter the ACFM (Actual Cubic Feet per Minute): Input the total volume of air flowing through your dust collection system.
⦿ Enter the Filter Cloth Area: Input the total surface area (in square feet) of all the filter bags or cartridges combined inside the dust collector.
⦿ Calculate: Click the calculate button to generate your ratio. This number tells you how many cubic feet of air are passing through each square foot of filter media per minute. You can then use the buttons below the calculator to email yourself a PDF summary of the results or request a free system sizing consultation from our engineering team.
Understanding the Formula
Air to Cloth Ratio = ACFM ÷ Cloth Area
The Air-to-Cloth Ratio (also known as filtration velocity) is one of the most critical metrics in dust collector design. It measures the speed at which air passes through the filter media.
⦿ A lower ratio means air moves slower through the filters, which generally increases filter life, reduces pressure drop, and improves collection efficiency.
⦿ A higher ratio means faster-moving air, which can be acceptable for larger or highly agglomerative dust particles, but often leads to rapid filter blinding, abrasion, and higher maintenance costs if misapplied.
Importance of Air-to-Cloth Ratio in Baghouse Design
A high or aggressive air-to-cloth ratio essentially means too much air and dust is being pushed through too few filters, too small of a dust collector. Larger airflows and greater dust loads require more filter area in order to work properly. Also, other factors such as the type of dust, dust load, temperature, humidity and the chemicals present in the gas stream may require a more conservative air-to-cloth ratio in order to function properly.
Note: This calculation is a good starting point, but duct material, layout, and type of dust must be considered. Consult with a dust collection expert to get a safe and efficient design.