There's a couple threads on Beta ratio, but most of them seem not to adequately explain it, just treat it like it's some kind of voodoo you have to translate from efficiency. Hopefully this post will help you understand what Beta is, and why it's advantageous.
Beta is simple: it's the ratio of the *count* of particles upstream vs downstream of a filter element, considering only particles in some stated size range in a given volume of fluid.
For example, a beta of 1000 at >7microns means that of all the particles 7 microns or larger, you'd expect only 1/1000 to get through the media in a single pass. Since it's removing 999/1000 particles, you could think of this as 99.9% efficiency. Beta of 10,000 is 99.99% efficiency. Thinking in terms of efficiency doesn't clearly communicate that 99.9% efficient is TEN TIMES the efficiency of 99% efficient, but when you think in term of Beta Ratio, it's obvious that a Beta of 10,000 is 10x that of 1000.
Beta is particularly useful in combination with ISO4406 cleanliness specification. Because the ISO standard actually counts particles (commonly at >4 micron, >6 micron, and >14 micron), you can use Beta ratio combined with cleanliness to quantify with higher precision the actual number of particles and their sizes.
ISO 4406 assigns a "code" to a range of particle counts as follows:
A beta ratio makes it easy to determine the impact of filtration on an ISO code. Let's say you have a fluid that is ISO 18 at >4microns, meaning it has 1300-2500 particles >4 micron per ml of fluid volume.
If I have a filter that is a beta of 1000 at >4 microns, then I can know that the particle counts downstream of the filter are 1.3-2.5 per milliliter. That means the downstream fluid would have an ISO code of 8. In short, my beta ratio allowed me to easily determine that ISO18 becomes ISO8.
The trick with beta, which it shares with efficiency, is that it MUST be apples to apples in terms of micron sizes. You can't add a beta at >4 microns to one at >7 microns, they have nothing to do with each other. A beta ratio without a micron rating is useless. It's like a flow rate without a pressure or restriction reference. Again, this limitation is shared with efficiency, so it's not a weakness of the beta rating. Betas will multiply in series if they use the same micron cutoff. If you place two filters in series that are each beta=1000, you'll have an effective Beta of a million. This is why so many fuel filter systems on diesel engines use two filtration stages.
Modern synthetic media can be extraordinarily efficient at removing particles of larger size. I received fuel filter test data that justified a startling conclusion, in the form of the answer to this hypothetical: How many gallons of fuel must pass through a fleetguard Industrial Pro filter element (nominally beta>1000 @>7 micron) using Cummins spec fuel (no worse than 18/16/13 per ISO 4406) to achieve a statistical certainty that a SINGLE PARTICLE of 14 microns or larger would get through??
Answer?
It turns out that the filter that is a beta >1000 at 7 microns has a much higher beta at 14 microns. How much higher? About 1.18x10^20. Which means to assure a single particle 14 microns or larger gets through this fuel filter, you'd need to pass over 590 million Olympic swimming pools full of Cummins-spec diesel fuel through the filter. Or roughly 3.9x10^14 gallons of fuel. For a single 14 micron particle. That's pretty good efficiency.
Beta ratios make filter analysis and fluid cleanliness easier to measure, analyze, and track. It what industry pros use to lay out filter architecture and establish recommended service intervals.
Learn to understand and appreciate Beta ratio as a better alternative to "efficiency" and you will be well-served.
Beta is simple: it's the ratio of the *count* of particles upstream vs downstream of a filter element, considering only particles in some stated size range in a given volume of fluid.
For example, a beta of 1000 at >7microns means that of all the particles 7 microns or larger, you'd expect only 1/1000 to get through the media in a single pass. Since it's removing 999/1000 particles, you could think of this as 99.9% efficiency. Beta of 10,000 is 99.99% efficiency. Thinking in terms of efficiency doesn't clearly communicate that 99.9% efficient is TEN TIMES the efficiency of 99% efficient, but when you think in term of Beta Ratio, it's obvious that a Beta of 10,000 is 10x that of 1000.
Beta is particularly useful in combination with ISO4406 cleanliness specification. Because the ISO standard actually counts particles (commonly at >4 micron, >6 micron, and >14 micron), you can use Beta ratio combined with cleanliness to quantify with higher precision the actual number of particles and their sizes.
ISO 4406 assigns a "code" to a range of particle counts as follows:
A beta ratio makes it easy to determine the impact of filtration on an ISO code. Let's say you have a fluid that is ISO 18 at >4microns, meaning it has 1300-2500 particles >4 micron per ml of fluid volume.
If I have a filter that is a beta of 1000 at >4 microns, then I can know that the particle counts downstream of the filter are 1.3-2.5 per milliliter. That means the downstream fluid would have an ISO code of 8. In short, my beta ratio allowed me to easily determine that ISO18 becomes ISO8.
The trick with beta, which it shares with efficiency, is that it MUST be apples to apples in terms of micron sizes. You can't add a beta at >4 microns to one at >7 microns, they have nothing to do with each other. A beta ratio without a micron rating is useless. It's like a flow rate without a pressure or restriction reference. Again, this limitation is shared with efficiency, so it's not a weakness of the beta rating. Betas will multiply in series if they use the same micron cutoff. If you place two filters in series that are each beta=1000, you'll have an effective Beta of a million. This is why so many fuel filter systems on diesel engines use two filtration stages.
Modern synthetic media can be extraordinarily efficient at removing particles of larger size. I received fuel filter test data that justified a startling conclusion, in the form of the answer to this hypothetical: How many gallons of fuel must pass through a fleetguard Industrial Pro filter element (nominally beta>1000 @>7 micron) using Cummins spec fuel (no worse than 18/16/13 per ISO 4406) to achieve a statistical certainty that a SINGLE PARTICLE of 14 microns or larger would get through??
Answer?
It turns out that the filter that is a beta >1000 at 7 microns has a much higher beta at 14 microns. How much higher? About 1.18x10^20. Which means to assure a single particle 14 microns or larger gets through this fuel filter, you'd need to pass over 590 million Olympic swimming pools full of Cummins-spec diesel fuel through the filter. Or roughly 3.9x10^14 gallons of fuel. For a single 14 micron particle. That's pretty good efficiency.
Beta ratios make filter analysis and fluid cleanliness easier to measure, analyze, and track. It what industry pros use to lay out filter architecture and establish recommended service intervals.
Learn to understand and appreciate Beta ratio as a better alternative to "efficiency" and you will be well-served.
/JK
