Overview
ISO/TS 13471-2:2022 provides a standardized procedure to correct the influence of temperature on vehicle noise measurements where tyre/road noise is a dominant component. It applies to pass-by testing methods (for example, the statistical pass-by (SPB) method in ISO 11819-1) and similar approaches (SIP, CTIM), and to pass-by tests on reference test tracks (ISO 10844). Measurement results taken at varying ambient and road temperatures are normalized to a reference temperature (20 °C) using the correction procedure specified in this Technical Specification.
Key Topics
- Scope and applicability: Corrections for tyre/road noise contribution in pass-by methods and non-accelerating track tests; distinction between vehicle categories and tyre classes.
- Temperatures considered: Ambient air temperature, road surface temperature, and optionally tyre temperature.
- Normalization target: Convert measured noise to the reference temperature 20 °C.
- Correction methodology:
- Temperature correction terms for tyre classes and vehicle groups.
- Temperature coefficients and spectral correction options.
- Compensation for mixed power unit noise where applicable.
- Measurement procedures:
- Guidance on temperature measurement equipment and sensor placement.
- Instructions for consistent air and (optional) road/tyre temperature measurement.
- Validity and limits:
- Defined temperature ranges within which the correction is valid (noting typical pass-by methods commonly permit measurements across a broad range, e.g., ~5 °C to 35 °C).
- Uncertainty and reporting:
- Uncertainty assessment in accordance with ISO/IEC Guide 98‑3 (GUM).
- Reporting requirements and recommended test report content.
- Annexes: Informative material on road surface types and selection of normalization temperature.
Applications
- Vehicle and tyre manufacturers: Normalize pass-by noise results for design, comparison, type approval, and labelling.
- Test laboratories and certification bodies: Apply temperature corrections to reduce measurement variability and comply with regulatory test procedures.
- Regulators and policymakers: Evaluate noise emissions consistently across climates and test conditions.
- Acoustical consultants and researchers: Improve comparability of field and track measurements by accounting for temperature-driven variability.
Related Standards (if applicable)
- ISO 11819-1 - Statistical pass-by (SPB) method
- ISO 10844 - Reference surfaces for tyre/vehicle tests
- ISO/TS 13471-1 - (related CPX method guidance)
- ISO/IEC Guide 98-3 - Guide to the expression of uncertainty in measurement (GUM)
Keywords: ISO/TS 13471-2:2022, tyre/road noise, temperature correction, pass-by methods, ISO 11819-1, SPB, vehicle noise emission, road surface temperature, reference temperature 20 °C, measurement uncertainty.