What is a Micron and How Does Mesh Size Correlate

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5
 Min read
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June 1, 2022

Choosing the correct water filter for your home’s water system is important to making sure you get the most out of your purchase. When it comes to a Rusco filter, there are a few things you’ll want to consider before implementing one into your system. Determining what size filter you’ll need based on the inlet and outlet, as well as factoring in the number of GPM running through your system is something that should be taken into consideration. You’ll also want to know whether or not the filter is needed for a hot water or cold water application. Depending on where the filter will be placed within your system, you may need to select one that doesn’t have a T-body and instead select an option with an L-body or a combo body. Figuring out what micron size you need for your filter screen is also something important to consider, and today we’ll focus on exactly what a micron is and how mesh size correlates.

Before discussing different micron sizes and how they correlate to mesh, let’s take a moment to understand exactly what a micron is. The word micron is actually short for micrometer, which means one millionth of a meter. It’s essentially a unit of measurement that describes the size of the particles that are allowed to pass through. As an example, a filter with a 150-micron rating will not allow anything that is larger than 150 microns to pass through it.

When it comes to microns, the larger the number, the more that will be able to pass through. For example, gravel is the size of 2000 microns. If you have a screen size in your filter that is equal to 2000 microns, anything smaller than the size of gravel would be able to pass through that screen. On the other hand, a dust mite is the size of 20 microns. A screen equal to 20 microns in a filter would only allow particles smaller than the size of a dust mite to pass through. As far as micron size is concerned, you want to remember that the larger the number the more that will pass through and the smaller the number the less.

You can see an example here of different particle types and their relative micron size.

Micron Continuum

While it’s good to have an understanding of microns, if you purchase a water filter from Rusco you’ll discover that some of our filters utilize a different unit of measurement when it comes to screen size. In place of micron size, which is a standard unit of measurement throughout the industry, the mesh filters you purchase from Rusco are stamped with what is known as a mesh size. Mesh refers to the number of pores per square inch in a mesh material. A 24-mesh screen means that there are 24 pores in one square inch of mesh screen. A 1000-mesh screen means that there are 1000 pores in one square inch of mesh screen.

When it comes to mesh, the larger the number, the less that will be able to pass through. For example, ragweed pollen is about the size of 370 mesh. If you were to have a screen size in your filter that is equal to 370 mesh, it would take something smaller than ragweed pollen to pass through that screen. On the other hand, a coffee ground is about the size of 50 mesh. A screen equal to 50 mesh would allow anything smaller than a coffee ground to pass through that screen. As far as mesh size is concerned, you want to remember that the smaller the number the more that will pass through and the larger the number the less.

At Rusco, we generally offer nine mesh sizes when it comes to polyester screens. To better understand how microns compare to mesh, below is a list of the conversions.

Mesh Micron What It Filters
24 700 Shale, Sand, Shell, Debris
30 500 Pipe Scale, Coarse Sand
40 350 Pipe Scale, Coarse Sand
60 250 Fine Sand
100 150 Grit
140 100 Grit
250 50 Grit
500 30 Very Fine Sand, Grit
1000 15 Ultra Fine, Fine grained, Powder, Dust-like sediment

If you’d like to learn more about different mesh and micron sizes and which one is right for your application, give Rusco a call at 1-800-345-1033. A live customer service representative will be available to help answer your questions.