ISO 29042-3:2009

Overview - ISO 29042-3:2009 (Safety of machinery, test bench method)

ISO 29042-3:2009 specifies a test bench method to measure the emission rate of a given airborne hazardous substance from machinery under defined operating conditions. Part of the ISO 29042 series on the evaluation of airborne hazardous substance emissions, this type‑B standard defines the physical test‑bench setup, sampling principles and measurement procedures to produce repeatable emission rate data for gases and particle fractions.

Key topics & technical requirements

• Test bench configuration: a test cabin with an inlet, funnel, measurement duct and fan; a mixing device (axial fan or equivalent) ensures uniform concentration at the sampling plane.
• Airflow control: constant air volume flow Q in the measurement duct determines average cabin velocity U. Typical guideline velocities:
  • 0.1 m/s for gases and respirable particles
  • 0.5 m/s for larger inhalable particles
• Sampling and mixing: representative sampling requires efficient mixing and a minimum of four samplers (five found optimum in a referenced study). Particle sampling should be isokinetic where appropriate.
• Test execution:
  • Machine positioned so emissions are carried to the sampling plane; operator and extraction devices must not obstruct the source-to-sampler path.
  • Machines operated according to intended use and manufacturer instructions; pollutant control systems may be tested both de-activated (uncontrolled) and activated (controlled).
  • At least three tests are required; sampling must continue after pollutant generation stops to capture remaining airborne emissions.
• Results & calculations: emission rates are calculated from the measured concentration(s) at the sampling plane and the measured air volume flow (concentration × flow integrated over test time). Emission rate reported as the mean of test results.
• Test report content: includes machine description, operational data, measurement methods and instruments, calibration dates, environmental conditions, number of tests and results.

Practical applications

• Evaluate and compare machine performance for airborne pollutant emissions
• Measure effectiveness of pollutant control systems (capture, separators, wetting)
• Rank machines by emission rate or establish state‑of‑the‑art emission levels
• Support conformity assessment, product development, and workplace risk assessments

Who should use ISO 29042-3:2009

• Machine manufacturers and designers assessing emission performance
• Test laboratories and certification bodies conducting standardized emission tests
• Occupational hygiene and safety engineers evaluating machine emissions
• R&D teams developing emission control solutions and product comparisons

Related standards

• ISO 29042-1 (Selection of test methods)
• ISO 29042-2 (Tracer gas method)
• ISO 29042-4 (Tracer method for capture efficiency)
• ISO 12100-1 (Basic machinery safety terminology)
• ISO 7708 (Particle size fraction definitions)
• EN 1093-3 (basis for this part)

Keywords: ISO 29042-3:2009, safety of machinery, emission rate, test bench method, airborne hazardous substances, sampling plane, isokinetic sampling, test cabin, air flow measurement.