ISO 11171 has functioned as the benchmark for particle counting in hydraulic fluids and lubricants for many years. It details the use of Light Obscuration (LO), a method that measures particle size by how much light they block.
LO is effective in many contexts, but this technique is less suitable for contemporary reliability and contamination analysis, where particle shape and type offer critical insight into failure modes, wear, and contamination sources.
Equipment tolerances continue to tighten, and uptime expectations continue to grow, prompting industry professionals to demand more from their chosen particle monitoring tools.
ISO 21018: A Modern Approach
ISO 21018 (Part 1) is designed to address this gap. This new international standard acknowledges that conventional LO-based particle counting cannot differentiate between water droplets, air bubbles, fibers, or metallic debris, which may appear the same size during analysis but have significantly different consequences for machinery.
ISO 21018 opens the door to Dynamic Image Analysis (DIA) and other alternative, image-based methods, which offer:
- Genuine images of particles
- Key size and shape metrics
- Traceability via thumbnail records
- Improved identification of root causes
This is a significant and especially timely development in the analysis of fluid cleanliness, particularly for lubrication professionals.
ISO 21018 at Reliable Plant 2025
Vision Analytical took the stage at the Reliable Plant Conference in June 2025 to discuss several important topics, including:
- A comparison between ISO 11171 and ISO 21018
- Real-world examples of Dynamic Image Analysis in lubrication applications
- How Vision Analytical’s Raptor system aligns with ISO 21018 standards
🔬 ISO 21018-1 Dynamic Image Analysis: Particle Contamination Monitoring | Reliable Plant 2025
Video Credit: Vision Analytical Inc.
Dynamic Image Analysis is a powerful tool able to acquire high-speed images of flowing particles. This allows detailed, real-time characterization. DIA differs from LO systems in that it does not guess shape from shadows; rather, it displays the actual particle geometry.
Systems like the Raptor analyzer allow users to:
- Count and classify particles based on their shape rather than simply their size
- View particle thumbnails for each individual sample
- Reduce misidentification from water droplets or bubbles
- Work in line with ISO 21018’s criteria for image-based particle monitoring
DIA goes beyond numbers; it uncovers the full picture of what’s occurring in the system.
Conclusion
Users relying solely on ISO 11171-compliant LO systems are advised to consider more advanced tools. Dynamic Imaging Analysis aligns with the future of particle monitoring, whether in the management of turbines, industrial gearboxes, or hydraulic systems, or in laboratories evaluating lubricant health.
Acknowledgments
Produced from materials originally authored by Peter Bouza from Vision Analytical Incorporated.
This information has been sourced, reviewed, and adapted from materials provided by Vision Analytical Inc.
For more information on this source, please visit Vision Analytical Inc.