Overview
ISO 21131:2019 specifies noise limits, measurement methods and hearing protection requirements for marine cranes. The standard applies to electro-hydraulic cylinder luffing cranes, electro-hydraulic wire rope luffing cranes and electric wire rope luffing cranes and is intended for noise assessment and operator protection on board ships and offshore units. Key focus areas include A-weighted noise limits (dB(A)), standardized measurement procedures and signage/demarcation for high-noise zones.
Key topics and requirements
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Noise limits and exposure
- Operating console: 85 dB(A) limit (recommendation: up to 75 dB(A) preferred)
- Engine room and structure exterior: 110 dB(A)
- Base exterior: 85 dB(A)
- Maximum exposure duration: 8 hours for the listed zones
- Hearing protection advised or required where levels approach or exceed thresholds; hearing protection should reduce exposure to ≤ 85 dB(A)
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Measurement methods
- Use an integral sound level meter compliant with IEC 61672-1 (or nationally recognized equivalent)
- All equipment must be within its calibration period
- Measurement conditions:
- Single-action hoisting, luffing and slewing at 80% rated load in hook mode
- Single-action hoisting, luffing and slewing at 100% rated load in grab mode
- Measurement positions and procedure:
- Sound level meter height between 1.2 m and 1.6 m
- Distance between measurement points ≥ 1 m; intervals between points ≤ 3 m
- Take measurements at at least 3 points in normal access areas (avoiding reflections and within defined distances from power units)
- Measurement uncertainty requirements follow ISO 3746
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Reporting and uncertainty
- Measurement report must include crane and running conditions, environment, equipment, background noise, organization/personnel and results
- Uncertainty assessment per ISO 3746 (condition uncertainty and repeatability)
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Noise control and signage
- Areas > 85 dB(A) must be demarcated and require hearing protection
- Operating console: cab shelter or insulation if >85 dB(A)
- Engine room: mandatory hearing protection for personnel
- Warning texts and safety signs specified for bands (80–85, 85–110, 110–115, >115 dB(A))
Applications and who uses it
- Crane manufacturers and designers: to design low-noise cabins, enclosures and drivetrain layouts
- Shipbuilders and OEMs: for factory acceptance testing and onboard installation checks
- Marine acoustic engineers and surveyors: to perform noise assessments and produce compliant measurement reports
- Ship operators, deck officers and safety managers: to set PPE policies, signage placement and maintenance plans
- Regulatory authorities and classification societies: for verification and certification of noise compliance
Related standards
Keywords: ISO 21131, marine cranes, noise limits, noise measurement, hearing protection, A-weighted dB(A), crane noise assessment, marine crane acoustics.