Overview - ISO 5131:2015 (Tractor noise measurement, survey method)
ISO 5131:2015 specifies a standardized survey method for measuring and reporting noise at the operator’s position of tractors used in agriculture and forestry. The standard applies to the basic machine with machine‑carried operators and is intended to give a realistic, repeatable assessment of the maximum noise exposure an operator can experience. Results are presented to help operators, manufacturers and test labs identify and avoid hearing‑risk levels when operating tractors.
Key topics and technical requirements
- Scope and purpose: Measurement of sound pressure level at the operator’s position for tractors (agricultural and forestry), to inform on potential hearing risk.
- Survey method definition: Test procedures are survey methods as defined in ISO 12001.
- Instrumentation: Use a precision Class 1 sound level meter meeting IEC 61672‑1; calibrate with an acoustical calibrator per IEC 60942. Measurements use A‑weighting (dB(A)) and slow response.
- Microphone location: For seated operators, microphone centre is 700 mm ± 20 mm above the seat index point (SIP), 100 mm ± 20 mm forward of SIP, and 250 mm ± 20 mm to the side (on the louder side); axis horizontal, diaphragm facing forward. SIP determined per ISO 5353.
- Testing conditions: Quiet, flat, open test area with minimal reflecting obstacles; surface of concrete/asphalt or specified alternatives for tracks. Background and wind noise must be at least 10 dB(A) below test levels.
- Measurement practice: Throttle usually fully open; allow 10 s stabilized running before recording. Record measurements in dB(A) to three significant figures. Make at least three readings per microphone position and operating condition - use the maximum of three consistent results (3 dB repeatability rule).
- Reporting and annexes: Test report format provided (Annex B). Annex A addresses agricultural tractor specifics; Annex C covers the Maintenance Agency.
Practical applications
- Establishing operator noise exposure benchmarks for occupational health and hearing conservation programs.
- Comparing tractor models for quieter operator environments during product development.
- Compliance testing, product information, and noise labelling for tractors used in agriculture and forestry.
- Providing repeatable, comparable noise data for purchasing decisions, insurance, and safety assessments.
Who should use ISO 5131:2015
- Tractor manufacturers and R&D teams
- Noise testing laboratories and certifying bodies
- Occupational health and safety professionals in agriculture/forestry
- Equipment distributors, fleet managers and purchasers
Related standards
Keywords: ISO 5131:2015, tractor noise measurement, operator noise, dB(A), sound level meter, survey method, agriculture and forestry, microphone location.
Open preview (PDF)Tractors for agriculture and forestry — Measurement of noise at the operator's position — Survey method
