ISO 6393:2008

Overview

ISO 6393:2008 defines a standardized method to determine the A-weighted sound power level emitted to the environment by earth‑moving machinery under stationary test conditions. The test is performed with the machine stationary and the engine running at rated speed under no‑load conditions. The procedure produces repeatable sound power data for compliance checks, noise reduction work and comparative assessments of construction equipment.

Key topics and requirements

• Scope and applicability: Applies to earth‑moving machinery as defined in ISO 6165 and as listed in Annex A of ISO 6393:2008.
• Measurement quantity: A‑weighted sound power level (LWA) calculated from time‑averaged A‑weighted sound pressure levels over a hemispherical measurement surface.
• Instrumentation: Preferred use of an integrating‑averaging sound level meter complying with IEC 61672‑1 class 1 specifications.
• Measurement surface and radii: Hemisphere radius is determined by the machine basic length (Annex A). Typical radii: 4 m (l < 1.5 m), 10 m (1.5 m ≤ l < 4 m), 16 m (4 m ≤ l < 8 m) or larger radii for longer machines.
• Microphone array and positions: Six microphone positions on the hemisphere as specified in the standard (coordinates provided).
• Measurement time: Each stabilized reading at a microphone position: 15–30 seconds.
• Test site and environmental correction (K): Acceptable ground types - hard reflecting plane (concrete/asphalt), combination hard plane + sand, or all‑sand plane. Environmental correction K may be neglected if |K| ≤ 0.5 dB for specified hard sites; otherwise K must be determined and applied.
• Background noise and climatic limits: Background noise corrections per ISO 3744; tests are not performed during precipitation, with snow cover, at temperatures below –10 °C or above +35 °C, or wind speeds over 8 m/s (windscreens required above 1 m/s).
• Machine set‑up and operation: Attachments intended for production use should be fitted; engine, fan and hydraulic systems warmed to normal operation; fan and engine speed requirements are specified.

Practical applications

• Demonstrating compliance with regulatory or purchaser noise limits for construction and earth‑moving equipment.
• Baseline noise reporting for product data sheets and type approval.
• Supporting noise reduction design, diagnostics and verification of noise control measures.
• Comparative testing between machine models or configurations.

Who uses this standard

• Manufacturers of earth‑moving machinery (design, testing, regulatory compliance).
• Test laboratories and acoustic consultants performing noise emission measurements.
• Regulatory bodies and procurement teams specifying noise performance for construction equipment.
• Researchers and engineers working on noise control and occupational/environmental acoustics.

Related standards

• ISO 3744 - Determination of sound power levels using sound pressure (engineering method).
• ISO 6165 - Earth‑moving machinery basic types and definitions.
• ISO 9249 - Engine test code (net power).
• IEC 61672‑1 - Sound level meters (instrumentation).
• Complementary ISO test codes: ISO 6394, ISO 6395, ISO 6396 (operator‑position and dynamic test methods).