The old ISO cleanliness code was particles > 2/5/15 microns.
The new ISO cleanliness code was particles > 4/6/14 microns.

We have some limits given on old code and oil analysis results given in new code, so I am interested in being able to understand/estimate the difference and possibly restate the old limits in terms of the new code (I realize I can compute either one if I have the raw data particle size distribution, but that's not my question.)

I always figured that if I analysed a sample distribution under the two codes, based on difference in cutoff points, the old code might result in a higher range number on the first and second numbers, while the new code might result in a higher range number on the third number (right?). For example, a given sample which was 21/18/15 under the old code MIGHT be 20/17/16 under the new code (right?). The exact difference would depend on actual particle distribution.

Now I see a chart which seems like it might be trying to address this issue but I don't know how to read the chart.
Take a look at Table 2 of the following article (you have to click on the Table 2 link after you get there)
http://www.machinerylubrication.com/article_detail.asp?...okgroup=Lubrication2

What is this table trying to tell me?

This message has been edited. Last edited by: electricpete,

Pete,

I don't think the chart is what you are looking for.

I just returned from a Noria training class last week. We went over this exact table. What this chart is trying to tell you is that if you increase your cleanliness levels you will get X amount of improved life from your machine. The box in the lower left relates to the 4 numbers in the other boxes in the table.

For instance if you take your current cleanliness level at a 21/18 and improve it to a 16/13 you could possibly see an improvement in equipment life/performance by a factor of 4 for hydraulic systems and diesel engines and a factor of 2.5 for rolling element bearings, 3 X for journal bearing machines and 2X for gearboxes.

Thanks Mike. That makes sense now.

Unless I missed something, there was no description at all in the article or table regarding what the table means.

MikeC is correct, that is just a life extension table that noria publish.
The new codes are very similar in the results given. The new ISO 4406:99 may give a slightly higher reading but this is negligible. Go to this link How the new ISO Particle Count will affect you.

Thanks Mate. It looks like that article addresses the differences well. I will have to take some time to digest it.