Beta??

[FrankN4]

I am looking at a spec sheet and it says: Beta 2/20=15/31. Nominal 19 microns. What is this telling me?

Thanks much

 

[tom slick]

purely a guess but it could refer to the statistical testing of the media. Beta is a way of measuring probability of error in their testing method.

if that is the case then it is not very useful to the end consumer. Hopefully I am way off and beta is some type of measure in filters.

do you have a link to the spec sheet?

 

[Tempest]

http://www.practicingoilanalysis.com/article_printer_friendly.asp?articleid=564

http://www.fram.com/pdf/FluidFilterRating.pdf

 

[FrankN4]

Does this then mean that the above filter would be 50% at 15 microns and 95% at 31 microns?

 

[Gary Allan]

Yes ..in the multipass test.

 

[Pablo]

You may find this helpful as well:

http://www.natrib.com/publications/appnotes/app_clean.php

 

[FrankN4]

I am probably missing something or not underestanding something, but, a filter with a Beta 2/20=15/31 doesn't sound like a very good filter. 31 microns is .0012 inch and 19 microns is .0007 inch. What about filters that talk about 10 to 12 micron filtration?

 

[Gary Allan]

They're typically called bypass filters, Frank. It depends on what efficiency level they're filtering at.

10um nominal (single pass 50%) isn't all that great.

15um at 98.67 (Beta 75 multipass test) is stellar.

The 2/20=15/31 is average ..or typical or whatever

It's not outstanding ..it isn't lousy

It is what it is ..and that's at least OEM spec.