Understand how the SAE AS4059 Standard works

Understand how the SAE AS4059 Standard, the replacement for the NAS 1638

Better performance, greater efficiency and cost savings. Over the years, technological advances have helped the productive sector a lot, offering the perfect solution for different situations and also making the operation easier and more precise.

Flow capacities were doubled, parts were reduced, more precision and speed were generated. However, modernity has also brought with it the need for more in-depth care for machines and equipment.

The increase in performance depends, to a great extent, on how the cleaning of fluid systems occurs, for example. This is because the smaller clearances made the equipment more sensitive to solid impurities.

Thus, the reduction of contaminants is essential so that parts do not wear out and, thus, unnecessary expenses are avoided. Such care avoids problems such as:

  • Increased consumption;
  • Reduced productivity
  • Wear of parts;
  • Constant need for maintenance;
  • Equipment stopped;

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A silent problem

It turns out that the problems highlighted above are not always noticed. We explain. Sometimes, the reduction in performance (and increase in expenses) occurs slowly, gradually. This prevents problems from being noticed at first. And that is precisely where the problem lies.

Just to give you an idea, the reduction in efficiency generated by the contamination of hydraulic systems, for example, can reach 20%. So, if you add up the accumulated loss in 10 months, that number can reach 100% of the production of 1 item.

That is, instead of having produced 100 pieces in 10 months, the equipment will have produced only 80. It is a very significant loss.

And, if there is no constant monitoring to reduce risks, problems can even cause the equipment (or machine) to be stopped for repairs. This is synonymous with spending and zero production for a certain period.

How to guarantee high performance?

The best way to maintain the efficiency and high performance of machines and equipment is through preventive maintenance. Among the main actions, microfiltration stands out (click here to learn more), a process responsible for removing impurities from the oil and, with this, preventing premature wear of parts. Click here to learn more! verified_user

But, how to know if the oil is contaminated?

The question may arise precisely at this point: how to know what is the limit of particles present to determine whether the fluid is dirty or not?

Fortunately, there are 2 regulations, which determine the criteria that define when the fluid is contaminated: the NAS 1638 and, more recently, the SAE AS4059.

The NAS 1638, best known and a reference for decades, has been replaced by the more modern and accurate SAE AS4059. Understand more below.

Understand the NAS 1638

The NAS 1638 standard is the traditional way of assessing the level of oil cleanliness since the 1970s. The NAS 1638 assesses the level of contamination by counting particles in 100 ml. For this, it establishes 5 different size ranges: which can be seen below:

  • From 5 to 15 micrometers
  • From 15 to 25 micrometers
  • From 25 to 50 micrometers
  • From 50 to 100 micrometers
  • Greater than or equal to 100 micrometers

Tip: The NAS 1638 is considered simple and practical. To learn more about it, you can read a full article, written by POC Filters, clicking here.

Read too

Understand the SAE AS4059

Since 2001, however, the official standard used to measure the degree of fluid cleanliness is SAE AS4059. As such, the NAS 1638 has been inactive for new projects since then.

SAE AS4059, which supplied the old standard, is considered more accurate. In other words, it was developed to overcome the existing limitations.

In fact, the quality of the new standard has made it widely accepted by companies in the sector, especially on the European continent. Therefore, understanding how SAE AS4059 works is important.

Important to know: the standards are periodically reviewed, and the same occurs with the SAE AS4059 standard. Quando ela surgiu, em 2001, a letra após o número era C. Depois, D e E. Agora, depois da última atualização, a letra é F. Ou seja, SAE AS4059 F.

But, what has changed?

In practical terms, with the SAE AS4059 standard, the reading was changed, as was the dimension of the contaminating particles. See comparison:

With the NAS 1638 (values in microns)

  • 5 μm, 10 μm, 15 μm, 25 μm, 50 μm and 100 μm

With SAE AS4059 (values in microns)

  • 4 μm, 6 μm, 14 μm, 21 μm, 38 μm and 70 μm

The changes started to follow more specific criteria, which are important for the hydraulic system of machines and equipment. However, as for the analysis, it is worth noting that the SAE AS4059 table is quite similar to that of NAS 1638. See the example below:

Table 1: amount of residues found in a 100 ml sample (the 2 standards present). The table shows the results differently.

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Amount of residues found in a 100 ml sample (the 2 standards present).

Table 2: in this case, you can see the same results, which this time are presented cumulatively (values considering a quantity of 100 ml).

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Table 2 indicates the same results, but presented cumulatively, that is, particles larger than 4µm, larger than 6µm and so on. It also considers the amount of 100ml.

Important note: as you can see in the tables, the way of reading remains the same. However, the values change. For example, where you read “5µm” NAS 1638, now you read “4µm” SAE AS4059.

And what to do with the equipment that is still based on the old standard?

Now that you know how the SAE AS4059 works, you may be wondering what happens to the manuals that still cite the old standard, the NAS 1638.

However, there is no cause for concern. In most cases, it is possible to contact the manufacturer and ask to update the document. Otherwise, the sector (or company) responsible for cleaning the equipment will know how to deal with the issue.

In addition, in case of doubts, you can contact POC Filters. We will be delighted and assist you in any situation, including to better understand how the SAE AS4059 works.


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