Overview
ISO 8573-2:2018 - Compressed air - Contaminant measurement - Part 2: Oil aerosol content specifies standard test methods for sampling and quantitatively analysing liquid oil and oil aerosols in compressed air. It excludes oil vapour (covered by ISO 8573‑5) and describes two principal sampling approaches: Method A (inline coalescing filters for full-flow, high-contamination sampling) and Method B (sampling discs with solvent extraction and laboratory analysis). The standard also documents alternative indicator-type detection devices (Annex E) and gives guidance on sampling selection, equipment, calculation, uncertainty and reporting.
Key topics and technical requirements
- Sampling methods
- Method A: Full-flow sampling through two high-efficiency coalescing filters; intended for heavy oil contamination and wall-flow measurement. Typical sampling times are long (e.g., dozens to hundreds of hours).
- Method B: Uses sampling discs mounted in a holder; subdivided into B1 (full-flow) and B2 (partial-flow) to suit lower-level oil monitoring and shorter sampling durations.
- Analytical techniques
- Solvent extraction of collected oil followed by infrared spectrometry (IR) or gas chromatography with flame ionization detection (GC‑FID) for quantitative analysis.
- Performance characteristics
- Guidance on detection ranges and typical sampling durations (Method A for higher concentrations, Method B for low-to-moderate concentrations).
- Reference conditions for volume statements: 20 °C, 100 kPa, zero water vapour.
- Protocol elements
- Equipment descriptions, isokinetic sampling arrangements, sample handling, calibration and recovery checks, calculation of oil concentration, limit of detection and estimation of measurement uncertainty.
- Supporting material
- Informative annexes with typical test reports, equipment layouts, and worked IR / GC-FID examples.
Applications and who uses it
ISO 8573-2:2018 is used by:
- Compressor and air-treatment equipment manufacturers for validation and product development.
- Air quality laboratories performing compressed air contamination testing.
- Maintenance and reliability engineers monitoring compressed air systems.
- Quality and compliance teams in industries where air purity is critical (pharmaceuticals, food & beverage, electronics, automotive).
- Certification bodies and consultants defining compressed air purity and contamination controls.
Practical benefits include standardized sampling workflows, comparable laboratory results, informed selection of filtration and treatment solutions, and documented evidence for regulatory or customer compliance.
Related standards
- ISO 8573-1 - Compressed air - Contaminants and purity classes
- ISO 8573-5 - Test methods for oil vapour and organic solvent content
- ISO 12500-1 - Filters for compressed air - Test methods - Oil aerosols
- ISO 3857-4 - Vocabulary - Air treatment
Keywords: ISO 8573-2:2018, compressed air, oil aerosol, sampling, Method A, Method B, coalescing filters, sampling discs, IR spectrometry, GC-FID, compressed air contamination.