Diesel Fuel and Oil filter Micron Ratings.
Posted: Wed Jan 11, 2006 10:50 pm
Thought some people might be interested in this:
When comparing diesel or oil filters between manufacturers by their micron ratings, you should use care, because the system one manufacturer uses is not the same as another.
Contrary to popular belief, filters do not work like seives (only for huge particles), and for this reason they do not remove all particles of a given size. The micron rating that a manufacturer gives, is therefore the MINIMUM SIZE AT WHICH THE FILTER HAS ACCEPTABLE FILTRATION EFFICIENCY. But what is acceptable filtration efficiency (in the eyes of the manufacturer) could be 100%, 98% or even 50% - in fact 50% is commonly used to make filters sound better. There is an ISO standard for working out the correct rating, but most manufacturers do not use it (I believe Donaldson and Mann Filter do use the standard, but not 100% certain).
To illustrate this - a filtration efficiency curve is attached - this is a typical curve for an extremely efficient diesel fuel filter.
So the bottom line is - a 10 micron filter from one manufacturer and a 5 micron filter from another MAY basically be the same filter. And the example below could be called anything from a 1 micron to a 5 micron filter, depending on the manufacturer.
When comparing diesel or oil filters between manufacturers by their micron ratings, you should use care, because the system one manufacturer uses is not the same as another.
Contrary to popular belief, filters do not work like seives (only for huge particles), and for this reason they do not remove all particles of a given size. The micron rating that a manufacturer gives, is therefore the MINIMUM SIZE AT WHICH THE FILTER HAS ACCEPTABLE FILTRATION EFFICIENCY. But what is acceptable filtration efficiency (in the eyes of the manufacturer) could be 100%, 98% or even 50% - in fact 50% is commonly used to make filters sound better. There is an ISO standard for working out the correct rating, but most manufacturers do not use it (I believe Donaldson and Mann Filter do use the standard, but not 100% certain).
To illustrate this - a filtration efficiency curve is attached - this is a typical curve for an extremely efficient diesel fuel filter.
So the bottom line is - a 10 micron filter from one manufacturer and a 5 micron filter from another MAY basically be the same filter. And the example below could be called anything from a 1 micron to a 5 micron filter, depending on the manufacturer.
