ISO 6394:2008

Overview - ISO 6394:2008 (Earth‑moving machinery noise at operator’s position)

ISO 6394:2008 specifies a repeatable method to determine the time‑averaged A‑weighted emission sound pressure level at the operator’s position of earth‑moving machinery under stationary test conditions (machine stationary, engine at rated speed, no‑load). It applies to earth‑moving machines as defined in ISO 6165 and complements ISO 6393 (sound power) and the dynamic test standards ISO 6395/6396. The standard is an extension of ISO 11201 (general measurement method) and is intended for compliance testing, product development and noise‑reduction investigations.

Key topics and technical requirements

• Measurement quantity: Time‑averaged A‑weighted sound pressure level (LpA,T) at the operator’s position.
• Test condition: Machine stationary, engine at manufacturer’s rated speed under no‑load conditions.
• Instrumentation: Preferably an integrating‑averaging, Class‑1 sound level meter compliant with IEC 61672‑1.
• Operator setup:
  • Ride‑on operators seated in normal driving position; seat set near midpoint of horizontal/vertical adjustments.
  • Pedestrian‑controlled operators in usual working position; standing stature specified (1 715 mm ± 50 mm).
  • No sound‑absorptive clothing or head coverings that affect measurements (except safety helmets or microphone supports).
• Microphone position & mounting:
  • Oriented horizontally toward operator’s normal look direction.
  • Located 200 mm ± 20 mm from the head median plane, in line with the eyes, on the side with the highest measured level.
  • Can be mounted on helmet, frame or shoulder harness; avoid vibration and reflections (≥100 mm from side of head, ≥50 mm above clothing).
• Measurement procedure: At least three series of readings (each 15–30 s); if two values differ by ≤1 dB further readings unnecessary. Report the arithmetic mean of the two highest values within 1 dB.
• Cab conditions: With AC/pressurized ventilation - doors/windows closed and system operating at specified speed; without AC - measure closed and open, report the higher result.
• Reporting & records: Machine ID (manufacturer, model, serial), engine net power and speed (ISO 9249), fan‑drive details, site conditions, instrumentation/calibration, individual readings, background noise and final reported LpA,T.
• Uncertainty/declaration: Annex A defines declaration procedures and considers measurement/reproducibility uncertainties (standard reproducibility up to 2.5 dB per ISO 11201/ISO 4871).

Applications - who uses ISO 6394:2008

• OEMs and R&D teams for noise design and verification of earth‑moving machinery.
• Test laboratories and certification bodies performing operator‑position noise measurements.
• Regulatory bodies and procurement agencies assessing compliance with noise limits.
• Occupational health and safety specialists evaluating operator noise exposure and mitigation measures.
• Product managers creating declared noise data for marketing, labeling or regulatory submission.

Related standards

• ISO 11201 - general method for emission sound pressure at work stations
• ISO 6393:2008 - sound power level, stationary conditions
• ISO 6395 / ISO 6396 - dynamic test conditions (sound power and operator position)
• ISO 6165, ISO 3411, ISO 9249, IEC 61672‑1 - referenced for definitions, operator dimensions, engine speed/power and instrument class

Keywords: ISO 6394:2008, earth‑moving machinery, emission sound pressure level, operator’s position, stationary test conditions, A‑weighted, noise measurement, ISO 11201.