ISO Cleanliness Code

ISO Cleanliness Code

What is the ISO Cleanliness Code of your Oil?

As we visit new and existing customers we hear sometimes the question:

  • What is your ISO Cleanliness Code? or
  • What are your ISO numbers? on a certain oil.

What they are referring to is the ISO 4406:1999 standard for oil cleanliness. In 1999 the International Standards Organization developed a system to rate and quantify the number of particles in the greater than or equal to 4 microns, 6 microns and 14-micron range. Please note that all the 6 and 14 micron particles are counted in the 4-micron section and the 14 micron particles are counted in the 6-micron section. To get an idea about the size of these partciles: The average diameter of a human hair is around 70 microns so you can imagine how small these particles are.

How to retrieve the ISO Cleanliness Code

A 100-ml sample is taken; the number and size of the particles are then determined by a Laser Optical Particle Counter or similar apparatus. This test is available through our Lab-Tech programm using the SO2 Advanced Oil Analysis.

ISO Cleanliness Code table

Let’s take the number 19/14/12 for example. These are the range numbers and are in ascending order 4μ, 6μ, and 14μ. (μ is the symbol for micron). This means that there are 250,000 to 500,000 particles 4μ or larger, 8,000 to 16,000 particles 6μ or larger and 2,000 to 4,000 particles 14μor larger in the 100-ml oil sample.

Why knowing the ISO Cleanliness Code?

Originally this standard was designed for hydraulic oils to determine if the oil was clean enough to pass through small orifices in valves, controllers, and actuators. It has been expanded to include gear oils, engine oils and various other industrial oils. The smaller the number the cleaner the oil. A 120LPM pump working 8 hours a day using a fluid that is rated ISO 18/16/13 will pass 9 kg of dirt in 200 days. Every time you open a container of oil you are introducing dirt into the oil.

Keep your oil clean

The cleanest oil available can be rapidly contaminated just by not cleaning off the top of the container prior to opening. Maintaining a clean fluid is a system wide approach. Start with a desired cleanliness target in mind, obtain an oil within that range and set up a regiment of cleanliness. Filter all new oil upon arrival and during transfer, seal all reservoirs and bulk tanks, install high quality particulate breathers and make a commitment to fluid cleanliness.

Oils with viscosity higher than ISO 460 may only have 2 numbers representing the 6μ and 14μ ranges as these oils are not usually found in systems requiring very clean oils. Here are some typical values for SWEPCO oils. Not all our oils have been tested to date as the demand has been low.

Product Typical ISO Code
201 14/13/6
702 12/8/9
703 13/11/8
704 14/12/9
755 12/8/9

As always please contact your SWEPCO agent if you have any questions.

Source: SWEPCO®
Southwestern Petroleum Corporation®

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