Overview
ISO 12500-2:2007 - Filters for compressed air - Test methods - Part 2: Oil vapours - specifies a standardized test layout and procedures for evaluating hydrocarbon vapour adsorbent filters (for example, activated carbon) used in compressed air systems. The standard defines how to determine key performance metrics - primarily adsorptive capacity (mass of hydrocarbon vapour a filter adsorbs) and pressure drop - and presents a method for reporting hydrocarbon-vapour capacity in milligrams under defined test conditions.
Key topics and technical requirements
- Test scope and layout: Detailed schematic test arrangement (evaporator, hydrocarbon vapour detector, flow controls, bypass, data recorder) and material/assembly recommendations (e.g., stainless-steel piping, grounding).
- Test agent: Liquid n‑hexane (≥98% purity) is prescribed to simulate compressor oil vapour challenge.
- Reference conditions: Standard reference gas conditions (air temperature ~20 °C, absolute pressure ~100 kPa) and use of equivalent rated flow at 700 kPa [7 bar(e)] for velocity equivalence.
- Breakthrough definition: Downstream concentration reaching 1 mg/kg constitutes breakthrough; time to breakthrough is recorded.
- Measurements:
- Upstream and downstream hydrocarbon concentration (e.g., flame-ionization detector or infrared analyser per ISO 8573-6).
- Differential pressure (pressure drop) across the filter under test.
- At least three samples per model; results averaged.
- Adsorbed mass calculation: The standard provides the calculation method to convert concentration, flow and time-to-breakthrough into milligrams of adsorbed hydrocarbon.
- Uncertainty & reporting: Guidance on measurement uncertainty and required test-report data (statement of conformity, model numbers, average adsorbed mass, pressure drop). Annexes include equipment description and a sample report form.
Applications and who uses this standard
ISO 12500-2:2007 is used by:
- Filter manufacturers - to rate and publish hydrocarbon-vapour capacities and pressure-drop data.
- Compressed air system designers and integrators - for filter selection and sizing to meet purity targets.
- Test laboratories and certification bodies - to perform reproducible performance tests and validate manufacturer claims.
- Maintenance and facilities managers - to estimate service life and replacement intervals for activated carbon or oil‑vapour filters.
- Specifiers and procurement teams - to write technical specifications requiring standardized test-based performance.
Practical applications include selecting oil‑vapour adsorbent filters to protect instrumentation, pneumatic controls, painting processes and food/pharma compressed-air systems where oil vapour and odour removal is critical.
Related standards
Keywords: ISO 12500-2:2007, filters for compressed air, oil vapours, hydrocarbon vapour adsorbent filters, activated carbon, adsorptive capacity, pressure drop, breakthrough, n‑hexane, compressed air test methods.
