Isokinetic Sampling in ISO 8573-4 Compliance
Accurate particle measurement as the foundation of compressed air quality
This article explains why isokinetic sampling is essential for reliable particle measurement in compressed air systems. It outlines the requirements of ISO 8573, the challenges of achieving correct sampling conditions in practice, and how SUTO iTEC’s isokinetic sampling device helps meet compliance with confidence.
The focus is on practical solutions for accurate, repeatable and representative measurements that support quality and safety in critical industries.
Page Overview
- Understanding ISO 8573 and the Role of Particle Measurement
- What Is Isokinetic Sampling
- The Challenge in Real Applications
- SUTO iTEC’s Technical Solution
- Ensuring ISO 8573-1 Compliance
- Applications in Critical Industries
- Integration with the S600 Analyzer
Understanding ISO 8573 and the Role of Particle Measurement
Compressed air must meet strict quality standards to ensure process safety and product reliability. The ISO 8573 standard defines the acceptable levels of contamination in compressed air systems.
ISO 8573-1 defines purity classes based on the presence of solid particles, water (as humidity or liquid), and oil (aerosol and vapor). ISO 8573-4 focuses on how particles are measured and requires that this be done under isokinetic conditions.
If sampling is not performed under isokinetic conditions, the results may not represent actual contamination levels. This can lead to incorrect classification and risks during audits or in regulated environments.
What Is Isokinetic Sampling
Isokinetic sampling ensures that the velocity of the air entering the sampling probe is equal to the velocity of the air in the main compressed air line. When these velocities match, the sample contains a representative concentration and size distribution of particles.
This prevents over-sampling due to too much suction or under-sampling due to low flow. It ensures that the data collected reflects the real condition of the system. Especially in critical applications, such as cleanrooms or sterile production, this accuracy is essential.
The Challenge in Real Applications
In actual industrial environments, airflow in the main distribution lines is rarely constant. System pressure, compressor load, and user demand fluctuate continuously. Manually adjusting the sample flow to match these changing conditions is nearly impossible.
Without controlled flow, isokinetic conditions cannot be guaranteed. This leads to unreliable measurements and potentially non-compliant air quality assessments.
SUTO iTEC’s Technical Solution
SUTO iTEC developed a compact isokinetic sampling device to meet the requirements of ISO 8573-4 and to solve the practical limitations of manual sampling. The device simulates a typical point of use in the compressed air system and maintains constant flow conditions regardless of upstream variations.
It includes an integrated flow meter for real-time monitoring and a needle valve for precise adjustment. This allows users to achieve and maintain isokinetic sampling flow with minimal effort. The device is designed to be used in combination with the S600 Portable Compressed Air Purity Analyzer, forming a complete system for on-site quality measurement.
Ensuring ISO 8573-1 Compliance
To determine whether a compressed air system meets the required cleanliness class, measurement results must be representative of actual conditions. Isokinetic sampling is the only reliable method for accurate particle analysis.
Without it, particles may be under- or over-sampled, leading to misleading results. In industries such as pharmaceutical production, food and beverage processing, electronics, and medical manufacturing, this can compromise product safety, process integrity, and regulatory compliance.
Applications in Critical Industries
The isokinetic sampling device is suited for all industries where compressed air purity directly affects production outcomes. This includes pharmaceutical manufacturing, cleanroom environments, food and beverage packaging, medical device production, and electronics or semiconductor fabrication.
In these sectors, even small errors in particle measurement can lead to major consequences, such as contamination, product recalls or failed audits. The ability to sample accurately and according to ISO requirements is therefore essential.
Integration with the S600 Analyzer
The isokinetic sampling device is fully compatible with the S600 Portable Compressed Air Purity Analyzer. Together, they allow users to monitor:
- Particles
- Humidity (as dew point)
- Oil vapor
- Pressure
The system offers guided workflows, plug and play setup and immediate report generation. The isokinetic sampling device ensures that particle measurements meet the accuracy and reproducibility required by ISO 8573-4.
Conclusion
Accurate particle measurement starts with proper sampling. Isokinetic sampling is a requirement under ISO 8573-4 and a fundamental part of reliable compressed air quality analysis.
SUTO iTEC’s isokinetic sampling device provides the necessary stability, precision and usability to perform particle measurement according to standard. It supports compliance with ISO 8573-1, protects production quality and simplifies testing in the field.
For any application where compressed air quality matters, it is the right solution to measure what truly counts.
