An ISO code, specifically referring to the ISO cleanliness code, is read as a sequence of three numbers that describe the level of particulate contamination in a fluid.
Understanding the ISO Cleanliness Code
The ISO cleanliness code quantifies the amount of particulate contamination within a fluid sample, measured per milliliter, across three different particle sizes: 4μ[c], 6μ[c], and 14μ[c]. The code is represented by three numbers, for example, 19/17/14. Each number in the sequence corresponds to the contaminant level for a specific particle size.
Breakdown of the ISO Code
Here’s how to interpret the sequence:
- First number (19 in the example): Represents the contamination level for particles of 4μ[c] and larger.
- Second number (17 in the example): Represents the contamination level for particles of 6μ[c] and larger.
- Third number (14 in the example): Represents the contamination level for particles of 14μ[c] and larger.
How the Numbers are Determined
Each number in the ISO code corresponds to a range of particle counts as defined in the ISO 4406:1999 standard (Note: Later standards exist but the core logic remains similar). This standard assigns a range of particle counts to each code, with higher numbers indicating higher contamination levels. It's important to consult a particle count chart to determine the actual number of particles per milliliter that each code represents.
Practical Insights
- Lower numbers mean cleaner fluid: A lower ISO code indicates a cleaner fluid with fewer particles.
- Different applications require different levels: The acceptable cleanliness level depends on the application. For example, sensitive hydraulic systems may require a much lower ISO code than less demanding systems.
Example
Let's consider the ISO code 19/17/14 again:
| Particle Size (µ[c]) | ISO Code | Interpretation |
|---|---|---|
| 4µ[c] and greater | 19 | Indicates a specific particle count range in the standard |
| 6µ[c] and greater | 17 | Indicates a specific particle count range in the standard |
| 14µ[c] and greater | 14 | Indicates a specific particle count range in the standard |
Conclusion
To read an ISO code, you must understand that each number in the sequence refers to the particle contamination level at a specific micron size. The lower the numbers, the cleaner the fluid.
