Poulton Le Fylde, FY6 8JU, UK

What is the difference between absolute and nominal ratings?

What is the difference between absolute and nominal ratings?

Nominal rating usually means the filter can capture a given percentage of particles of a stated size (e.g. 50% @ 10 micron). Absolute rating is the smallest typical particle size retained by a filter media at 98+% efficiency. This is also referred to as the Beta=75 or 98.67% efficiency rating.