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Cleanliness codes

M mcMember
I was wondering how many people actually know what codes they are working to. I was surprised to find that many of the companies that I have been contracted to work for are still getting their test results in NAS 1638 and ISO 4406:87. Most of these people were unaware that these codes had been replaced over 5 years ago. I think it is the responsibility of the labs themselves to make the average maintenance engineers aware that there have been updates.
How many people actually have labs that have their particle counters calibrated to ISO/FDIS 11171 standards? And do you think it is important?
One interesting comment I did receive was from a customer who said it was more important to have results that he could trend reliably rather then having particle counts that were representative of the system condition.
Just curious to know your thoughts on the subject.
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M mrhughesMember
MC.

We have new advanced particle counter instruments, and report usually in in
- NAS1638, ISO4406:89 & ISO4406:99 (and total particles pr ml., avg. particle size, maximum size)
- Or we replace NAS1638 with SAE AS4059D for customers who wants this.

The SAE AS4059D was intended to replace the NAS1638 for particle contamination on new hydraulic equipment.

The NAS1638 has never been replaced. It is still used, and I would claim its easyer to understand for an end user.

When doing particle counts with optical microscopy (ARP598b or ISO4407) you can only count particles down to 5 micron, and therefore cannot report in the ISO4406:99 system. This counting methodes are still accepted.

Anyway, when using automated particle counters I do agree its important to have equipment calibrated or compatible to ISO/FDIS 11171.
S sindhujaaMember
Dear MC / Huges,

I am intrested in oil technology and a regular visitor to this forum and am intrested to step into the cleaning of oil concept.

Could you please give me an idea about the cleanness codes and instruments to find out the NAS levels of oil before and after cleaning / filtering, also other tests like TAN erc. and please explain me about the tests .. Approximate cost of the same also.
L labMember
Just my opinion but I don't think the labs that are still using outdated calibration fluids will tell their customers that their results may not be as accurate as their competitor. We tell our customers to look for the "C" after the particle sizes (>4c, >6c, etc) on their report to insure that their particle counter is calibrated using NIST calibration fluids and to the new standard. We certainly make our customers aware that we are using the most current test methods.
C cameronMember
I agree with the first post that NAS was a lot easier to explain to customers. We know have three standards in use so i reckon next year the committees get together and measure the dust using the hubble telescope and get it super dooper accurate and make another code to make it even harder to explain to customers. It is this easy clean oil is clean oil no matter what code you measure it in, if you dont believe me take your lab coat off get in to the field and you will see a 15/12 vs a 16/15/11 is still clean and 20/16 vs 21/20/16 is still dirty makes no difference at all how the customer recieves his numbers they want to know is it clean or is it dirty. Until Particle Counters actually count particles like a manual count the numbers are not totally accurate anyway , yes even the latest laser counters do not count each particle(what happens when a 10 micron particle sits in front of a 5 micron particle??), and im sure the standard asks for a 100ml sample and how many machines actually use a 100ml? I think these standards need a lot of tidying up with the correct terminology used and made simple as lets face it, it is not rocket science just a very simple number scale.
D davowaMember
I find that like many other aspects of oil analysis and maintenance, people get a bee in their heads about one specific result. If the oil cleanliness is causing abnormal wear or if it is retarding goals of lowering wear rates then by all means try to improve it. This includes CORRECT reporting, calibration and sampling techniques should be used, but if the cleanliness of the fluid is NOT having any negative impact on the maintenance practices or reliability of a component then just accept what it is and look for abnormal trends or results as the results come in. There are too many labs reporting inaccurate results, even claiming silicon antifoam as "contamination". Not good for our industry or our customers. Help to educate the engineering fraternity so that they know the differences.
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