PPM in a UOA
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Depends on the lab and the method they use.
Wearcheck provides some of this info with their reports. If I'm reading it correctly, the particle size they analyze ranges from 10 to 20 μm.
By the way, this thread should have been posted in the "Oil Analysis - General Questions" subforum.
By the way, this thread should have been posted in the "Oil Analysis - General Questions" subforum.
Originally Posted By: dparm
Depends on the lab and the method they use.
yes and no. While different labs may get different readings based on the methodology used, the way the data are expressed (PPM) is universal. PPM is a fractional measurement, so it simply refers to 1 part out of a million--not a specific size of particle.
In practical terms, 1 ppm is roughly equivalent to a single drop in 50 liters. So, 10ppm in a 5 liter crank case would equal one single drop of contaminants.
Depends on the lab and the method they use.
yes and no. While different labs may get different readings based on the methodology used, the way the data are expressed (PPM) is universal. PPM is a fractional measurement, so it simply refers to 1 part out of a million--not a specific size of particle.
In practical terms, 1 ppm is roughly equivalent to a single drop in 50 liters. So, 10ppm in a 5 liter crank case would equal one single drop of contaminants.
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Originally Posted By: Quattro Pete
Wearcheck provides some of this info with their reports. If I'm reading it correctly, the particle size they analyze ranges from 10 to 20 μm.
By the way, this thread should have been posted in the "Oil Analysis - General Questions" subforum.
That looks like it is for particle count data, which would be different from the size of particles measured in the "metals" portion.
Wearcheck provides some of this info with their reports. If I'm reading it correctly, the particle size they analyze ranges from 10 to 20 μm.
By the way, this thread should have been posted in the "Oil Analysis - General Questions" subforum.
That looks like it is for particle count data, which would be different from the size of particles measured in the "metals" portion.
You may be right. This report is listed under the "Contaminants" section and not under the "Wear" section.
Originally Posted By: tig1
Just what is the size of 1PPM when it comes to metal PPM in a UOA?
It's Parts Per Million and that doesn't reflect size, just volume. The gas spectrometer tests used to give you the PPM number only "sees" small particles, typically around 5 microns or smaller. If you do a particle count, you'll see particles lots larger. I had a count done on one of my tractor engines as well as a "normal" UOA. Here are some of the results to contrast:
IH D358 diesel, 8197 hrs and almost 100 hrs on the oil
Iron- 13 ppm
Chrome- 1.3 ppm
Lead- 1 ppm
copper- 1 ppm
Aluminum- 13 ppm
Those are the wear metals "high spots" and in looking at them, you's say whoa, that engine is doing great, yet look at the actual particle count:
4-6u- 20,699,202
6-14u- 2,869,403
14-21u- 46,838
21-38u- 1,695
0 count for anything larger
ISO code: 25/22/16
I have seen only a few other tests where both a UOA and an optical particle count were done, and they were similar, but I really don't know if this is a typical picture of a UOA. I find it interesting that the oil filter used has an absolute rating of around 21u and that's where the particle count really drops off.
So, if this is a normal UOA snapshot, then there is a lot more going on than a single UOA is going to tell you. I imagine the people who can accurately interpret wear metals have seen the particle counts along with the spectrometer results and know what's truly "normal." When I think that most internal engine wear comes from the range from 10-20u, I'd want to filter a little better in that range.
Just what is the size of 1PPM when it comes to metal PPM in a UOA?
It's Parts Per Million and that doesn't reflect size, just volume. The gas spectrometer tests used to give you the PPM number only "sees" small particles, typically around 5 microns or smaller. If you do a particle count, you'll see particles lots larger. I had a count done on one of my tractor engines as well as a "normal" UOA. Here are some of the results to contrast:
IH D358 diesel, 8197 hrs and almost 100 hrs on the oil
Iron- 13 ppm
Chrome- 1.3 ppm
Lead- 1 ppm
copper- 1 ppm
Aluminum- 13 ppm
Those are the wear metals "high spots" and in looking at them, you's say whoa, that engine is doing great, yet look at the actual particle count:
4-6u- 20,699,202
6-14u- 2,869,403
14-21u- 46,838
21-38u- 1,695
0 count for anything larger
ISO code: 25/22/16
I have seen only a few other tests where both a UOA and an optical particle count were done, and they were similar, but I really don't know if this is a typical picture of a UOA. I find it interesting that the oil filter used has an absolute rating of around 21u and that's where the particle count really drops off.
So, if this is a normal UOA snapshot, then there is a lot more going on than a single UOA is going to tell you. I imagine the people who can accurately interpret wear metals have seen the particle counts along with the spectrometer results and know what's truly "normal." When I think that most internal engine wear comes from the range from 10-20u, I'd want to filter a little better in that range.
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