{"id":27530,"date":"2026-06-25T21:24:51","date_gmt":"2026-06-25T21:24:51","guid":{"rendered":"https:\/\/airtec.global\/?p=27530"},"modified":"2026-07-22T17:43:18","modified_gmt":"2026-07-22T17:43:18","slug":"iso-8573-4-isokinetic-sampling","status":"publish","type":"post","link":"https:\/\/airtec.global\/en\/2026\/06\/25\/iso-8573-4-isokinetic-sampling\/","title":{"rendered":"ISO 8573-4 and Isokinetic Sampling: The Critical Factor for Measuring Particles in Compressed Air"},"content":{"rendered":"
\n SUTO iTEC \u00b7 S600<\/span>\n

ISO 8573-4 and Isokinetic Sampling<\/h2>\n

ISO 8573-4 isokinetic sampling is the critical factor that determines whether your compressed air quality measurements are accurate or misleading. Many audits fail not because of the instrument, but because of incorrect sampling conditions. Here’s why.<\/p><\/div>\n\n\n\n

\n \"ISO\n<\/div>\n\n\n\n

What is ISO 8573 and Why Does It Matter?<\/h2>\n

ISO 8573 is the international standard used to classify compressed air quality. Its goal is to define the permitted levels of contaminants within an industrial compressed air system, mainly solid particles, moisture, and oil.<\/p>\n\n

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ISO 8573-1: Purity Classification<\/h3>\n

Establishes the purity classes of compressed air, defining maximum contamination limits permitted according to the industrial application. The pharmaceutical industry requires extremely low levels, while general applications may tolerate higher levels.<\/p>\n <\/div>\n

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ISO 8573-4: Measurement Method<\/h3>\n

While ISO 8573-1 defines the limits, ISO 8573-4 establishes how<\/strong> particle measurements must be performed: sampling techniques, counting methods, test conditions, and requirements for representative results.<\/p>\n <\/div>\n<\/div>\n\n\n\n

\n \"Sources\n<\/div>\n\n\n\n

What is Isokinetic Sampling?<\/h2>\n

Isokinetic sampling occurs when the velocity of air entering the sampling device is exactly equal to the velocity of air flowing inside the main pipeline. Although it may seem like a small detail, it is one of the most important factors for obtaining reliable particle measurements.<\/p>\n\n

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\u26a0 Over-sampling<\/h3>\n

If the inlet velocity to the sampler is higher<\/strong> than the main flow velocity, more particles than actually present are drawn in \u2014 especially large and heavy particles. Results appear falsely high<\/strong>.<\/p>\n <\/div>\n

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\u26a0 Under-sampling<\/h3>\n

If the inlet velocity is lower<\/strong>, heavier particles cannot enter the measurement system. The detected concentration is artificially reduced. Results appear falsely low<\/strong>.<\/p>\n <\/div>\n<\/div>\n\n

Without isokinetic conditions, even the best particle counter can deliver incorrect results.<\/strong><\/p>\n\n

The Real Challenge in Industrial Plants<\/h2>\n

In practice, maintaining isokinetic sampling manually is extremely difficult because compressed air systems are constantly changing: pressure variations, flow changes, variable production demand, and fluctuations between the main line and points of use. These conditions continuously modify the flow velocity inside the pipeline, causing many audits to generate inconsistent or poorly repeatable results.<\/p>\n\n\n\n

\n \"SUTO\n<\/div>\n\n\n\n

The Solution: SUTO iTEC S600 with Isokinetic Sampling<\/h2>\n

To solve this problem, SUTO iTEC developed the S600 Portable Compressed Air Purity Analyzer together with a specialized isokinetic sampling device designed in accordance with ISO 8573-4.<\/p>\n\n

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What does the S600 measure?<\/h3>\n