As is standard for the irrigation industry, nothing is standardized! Irrigation filters are no different. Some manufacturers use a Mesh number or size while others use a Micron size number. Selecting the best filter for your irrigation project is confusing enough without trying to figure out what the difference between mesh and micron is.

Mesh size is the “mesh number” (a US standard of measure for filter screens) in reference to the size of the opening in the screen. Mesh number technically refers to the number of openings in a linear inch (although many use a square inch) of the filter screen material. So a screen with 30 openings along a linear inch (or square inch) of material is considered a 30 mesh screen. As the mesh number increases, the size of openings decreases, thus the larger the mesh number, the finer the filtration.

Micron is a term of measurement used to describe the size of tiny particles. Thus in filter screens, micron size refers to the maximum size of a particle that will pass through the filter screen. To get an understanding of a micron sized particle - with good but average vision you can see objects as small as about a tenth of a millimeter. A micron is one-thousandth of a millimeter. So in essence, the smaller the micron number the finer the filtration.

In relationship to the size of particle that will pass through that opening, we must consider the strand size of the filter screen material. Type of material or wire size may differ, making the opening between strands vary. This may cause slight variances in mesh to micron conversion for various types of materials and manufacturers. It is important to remember that mesh size is not a precise measurement of particle (micron) size.

Noted below are some common particulates and their approximate micron size for comparison.

 Particulate Bacteria Clay Giardia Beach Sand Fine Sand Silt Plant Spores Viruses Micron Size 0.3 - 60 0.1 - 2 8 - 14 62.5 - 2000 125 - 250 2 - 50 3 - 100 0.005 - 0.3

Common Mesh to Micron Conversion Chart

 US Mesh Inches Micron Millimeters 30 0.0232 595 0.595 35 0.0197 500 0.500 40 0.0165 400 0.400 50 0.0117 297 0.297 60 0.0098 250 0.250 70 0.0083 210 0.210 80 0.0070 177 0.177 100 0.0059 149 0.149 120 0.0049 125 0.125 140 0.0041 105 0.105 170 0.0035 88 0.088 200 0.0029 75 0.075 230 0.0024 63 0.063 270 0.0021 53 0.053 325 0.0017 44 0.044 400 0.0015 37 0.037

For additional assistance in selecting a filter to match your irrigation needs see our Filter Buying Guide.