Air-to-Cloth Ratio: What Is It, and How Do I Calculate It?

Dust Collector Filter from A.C.T. Dust CollectorsAlso referred to as air-to-media ratio, air-to-cloth ratio quantifies the amount of air going through one square foot of filter media. It is often used as a simple way to state the ratio between cubic feet per minute (CFM) and square feet of filter area.


For example, if a dust collector was moving 4,000 CFM and had 2,000 square feet of filter area, we could say that it had a 4,000-to-2,000 ratio. This can be simplified to a 2:1 air-to-cloth ratio. So, to calculate air-to-cloth ratio for a dust collector, we take the amount of airflow (CFM) and divide it by the amount of filter area within a dust collector.

Using the right filter matters, and there are two standard types of dust collector filters: bag and cartridge. Bag filters consist of cylindrical bags (or tubes) made of fabric that can handle a more demanding application with heavier dust, such as wood and grain dust. Cartridge filters are very efficient for fine dust and lighter loading applications, such as welding, plasma, laser and other fume or smoke applications. Because cartridge filters are pleated, they have a larger total filtering surface area per CFM, which reduces the air-to-cloth ratio and size of the dust collector.

Why is AIR-TO-CLOTH RATIO important?

It is one of the more important factors in determining how long a filter will last in a given application. Although there are many factors that come into play when determining filter life, air-to-cloth ratios can give good guidance when determining the size of dust collector required for a given amount of air.

A lower air-to-cloth ratio will result in longer filter life and is often used in nuisance applications, while a higher air-to-cloth ratio will result in shorter filter life and is often used when dust loading is very light.

A.C.T. Dust Collectors offers the ultimate in air filtration. Interested in learning more? Contact us today and one of our experts will help you determine the best air-to-cloth ratio of bag filters and cartridge filters for your application.

ACTion Booth CTA | V1