Absolute Filtration and Norminal Filtration

Forgive me dear advisors,

I think now that attaching file in CR4 forum is not possible.

here you can click the web site I mentioned. No intentional advertisement.

Just sharing~!!!

http://www.oilanalysis.com/article_detail.asp?articleid=564

Not sure about your question, but to confuse the matter just a bit look here

Caution must be exercised when using beta ratios to compare filters because they do not take into account actual operating conditions such as flow surges and changes in temperature.

A filter's beta ratio also does not give any indication of its dirt-holding capacity, the total amount of contaminant that can be trapped by the filter throughout its life, nor does it account for its stability or performance over time.

Nevertheless, beta ratios are an effective way of gauging the expected performance of a filter.

Caution must be exercised when using beta ratios to compare filters because they do not take into account actual operating conditions such as flow surges and changes in temperature.

A filter's beta ratio also does not give any indication of its dirt-holding capacity, the total amount of contaminant that can be trapped by the filter throughout its life, nor does it account for its stability or performance over time.

Good answer,

I like to add it does not take into consideration of the filter media clean-ability after fouling (due to the filter media construction).

p911