ISO 29042-2:2009

Overview - ISO 29042-2:2009 (Tracer gas method)

ISO 29042-2:2009 - part of the ISO 29042 series on the safety of machinery - specifies a tracer gas method to measure the emission rate of a given gaseous pollutant from a single machine whose operation can be controlled. The standard defines the principle, required apparatus, measurement points, test room and field methods, test procedure, data analysis and reporting requirements for evaluating airborne hazardous substances using tracer gas techniques.

Key topics and technical requirements

• Principle: Use a tracer gas released at a known, constant rate that mimics the aerodynamic behaviour of the pollutant; measure tracer and pollutant concentrations to calculate pollutant emission rate.
• Scope: Applicable to controlled machines (test-room or in-situ/field testing); not retroactive to machines manufactured before publication.
• Apparatus:
  • Tracer gas emitter shaped to simulate the real source (point, plane or volumetric).
  • Tracer gas flow-rate meter and adjusting device.
  • Gas analyser(s) suitable for tracer and pollutant (IR, FID, electron capture, mass spectrometer noted).
  • Low-adsorption sampling lines (e.g., PTFE) and filters where necessary.
  • Recommended tracer gases (examples in the standard: helium, sulphur hexafluoride, nitrous oxide) chosen for low toxicity, stability, low background and measurability.
• Measurement points: At least three sample points around the machine (typically 1–3 m from source) positioned where the pollutant is generated.
• Procedure: Includes background measurement, stabilisation of analysers, tracer flow calibration, recording concentrations over time (typically several room time‑constants), and data analysis to express emission rates.
• Reporting: Test report content defined (test conditions, instrumentation, tracer gas flow, measured concentrations, calculation methods).

Applications and users

ISO 29042-2 is used for:

• Quantifying pollutant emission rates from machinery for risk assessment and exposure control.
• Designing or verifying ventilation, capture systems and local exhausts.
• Emission testing in test labs, workplace compliance checks, and product development.

Typical users:

• Machine manufacturers and designers
• Occupational hygienists and safety engineers
• Test laboratories and certification bodies
• Environmental and regulatory authorities

Related standards

• ISO 29042-1 - Selection of test methods (companion guidance)
• ISO 12100-1 - Safety of machinery - basic terminology and methodology
• Other parts of ISO 29042 series (test bench, capture efficiency, room methods) that address complementary test methods and parameters.

Keywords: ISO 29042-2, tracer gas method, emission rate, airborne hazardous substances, safety of machinery, tracer gas technique, gas analyser, test room method, field method.