Nominal Micron Rating ?

[rrounds]

When a filter manuf. says the filter has a 12 nominal micron rating, what test do they use to ad. that rating? And can you take the claim (12 Nominal Micron Rating) and put it into a (b2=20) type of rating? Or are there two totally different test to get those numbers and they mean two different things?

ROD

 

[fredfactory]

"The term “nominal” micron rating typically means that the filter is capable of removing 50% of a specific size particle, however, some companies’ “nominal” micron ratings may range anywhere from 1 to 98.6% efficient at removing a specific particle size. The term “absolute” micron rating means that the filter is capable of removing at least 98.7% of a specific size particle. This rating is far more accurate." --- http://www.baldwinfilter.com/ProductHighlights122010.html

 

[Sayjac]

You may find a better explanation linked below. As noted nominal typically means a micron rating at 50%. That said reading the thread, there seems to be a fudge factor or wiggle room in that definition. In other words it's open to interpretation. And one site in the link says it's unreliable now.

Absolute is a better, and anything with an ISO 4548-12 testing note next to it. That is the standard test procedure for filter efficiency.

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3229906/Nominal_vs_Absolute_micron_rat

 

[rrounds]

Thank's for the info. I should have known that, I know I read about it before but I just could not remember where.
As one who uses and trust Baldwin(have for 45 years) I should have remember that that is where I read it.

I think I'll start playing some memory games now. LOL

Thank's Again,
ROD