ISO 9645:1990 PDF

Acoustics — Measurement of noise emitted by two-wheeled mopeds in motion — Engineering method

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Title (English):

ISO 9645:1990

Acoustics — Measurement of noise emitted by two-wheeled mopeds in motion — Engineering method

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 3
Publication date:: March 29, 1990
Edition:: ISO IS 9645 edition 1 version 1
ICS:: 17.140.30

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Description (English):

La présente Norme internationale prescrit une méthode d'expertise pour le mesurage du bruit émis par les cyclomoteurs à deux roues en mouvement [tels qu'ils sont définis dans l'ISO 3833. La méthode est prévue pour satisfaire aux conditions requises de simplicité, dans la mesure où celles-ci sont compatibles avec la reproductibilité des résultats et le fonctionnement effectif du cyclomoteur. Les prescriptions visent à reproduire le niveau de bruit émis dans une circulation urbaine de caractère irrégulier, nécessitant la pleine utilisation de la puissance du moteur. NOTE -- La méthode d'essai nécessite un environnement acoustique qui ne peut être réalisé que sur un terrain découvert étendu. Ces conditions peuvent généralement être remplies lorsqu'il s'agit de mesurages effectués : soit en vue de la réception du type de cyclomoteur, soit en cours de fabrication, soit aux stations d'essais officielles. Il convient de remarquer que les contrôles sur route de cyclomoteurs en service peuvent rarement être effectués dans un environnement acoustique idéal. S'il est nécessaire d'exécuter des mesurages sur route dans un environnement acoustique qui ne satisfait pas aux conditions indiquées dans la présente Norme internationale, il est recommandé de tenir compte du fait que les résultats obtenus sont susceptibles d'être sensiblement différents des résultats obtenus en respectant les conditions prescrites. Une méthode mieux adaptée au contrôle sur route des cyclomoteurs en service sera prescrite dans une Norme internationale ultérieure.

Technical details

Technical committee: ISO/TC 43/SC 1 - Noise
SKU: ISO 9645:1990

Abstract

Overview

ISO 9645:1990 provides an engineering method for measuring noise emitted by two-wheeled mopeds in motion. The standard is intended to deliver objective, reproducible acoustic results suitable for type approval, production checks and official test stations. It defines site conditions, instrumentation, operating conditions and reporting requirements to ensure consistent measurement of moped noise.

Key takeaways: A‑weighted sound levels, Class 1 instrumentation, calibrated equipment, controlled test site and repeatable vehicle operating procedures.

Key Topics

Instrumentation and calibration
- Use a Class 1 sound level meter (per IEC 651) or equivalent.
- Measurements with frequency weighting A and time weighting F.
- Instrument calibration must be checked before and after tests; record deviations. If the calibration shift exceeds 1 dB during a series, the series is invalid.
Test site and environmental limits
- Test site must be essentially horizontal and dry, with the test track and the 10 m radius around the centre formed of hard surface (concrete, asphalt or equivalent).
- Within a 50 m radius of the track centre there should be no large reflective objects (buildings, bridges, rocks, fences).
- Wind: measurements with mean wind speed at the microphone exceeding 5 m/s are invalid.
- Background noise (including wind noise) must be at least 10 dB below the noise produced by the moped under test.
Microphone position and geometry
- Microphone height: 1.2 m ± 0.1 m above ground.
- Distance from microphone to the reference line on the track: 7.5 m ± 0.2 m.
- Microphone axis should be horizontal and perpendicular to the moped path.
Measurement procedure and validity
- At least three valid passes on each side of the moped are required.
- Record the maximum A‑weighted sound pressure level (with F weighting) during each pass between defined track lines.
- Results for a side are valid if the difference between extreme values of three consecutive valid measurements does not exceed 2 dB.
- The test result is the higher of the two arithmetic means (one per side), rounded to the nearest 0.5 dB.
Vehicle preparation and operating conditions
- Moped must be in running order with recommended fuel, spark plug(s) and carburetor settings.
- Total test mass (rider, test equipment and ballast) is specified in the standard (example range given in the text: 70–80 kg).
- Tyres must be of the type normally fitted and inflated to the manufacturer’s recommended pressure.

Applications

Type approval testing for manufacturers and regulatory bodies
Production-line verification and factory conformance checks
Accredited laboratory or official station acoustic evaluations

Related Standards

ISO 4164 (vehicle engine power test code) - referenced for engine power-related data
ISO 6726 (vocabulary for mopeds and motorcycles)
IEC 651 (sound level meters) - instrument class and performance

Reporting and Practical Value

The test report must document site and weather conditions, equipment identification and calibration values, background noise level, vehicle and transmission identification, engine speed data, number and values of A‑weighted readings, and the declared test result. Following ISO 9645:1990 helps ensure repeatable, comparable moped noise data for compliance, development and research purposes.

Related standards

Mentioned in the description and other ISO standards

Abstract

Overview

Key takeaways: A‑weighted sound levels, Class 1 instrumentation, calibrated equipment, controlled test site and repeatable vehicle operating procedures.

Key Topics

Instrumentation and calibration
- Use a Class 1 sound level meter (per IEC 651) or equivalent.
- Measurements with frequency weighting A and time weighting F.
- Instrument calibration must be checked before and after tests; record deviations. If the calibration shift exceeds 1 dB during a series, the series is invalid.
Test site and environmental limits
- Test site must be essentially horizontal and dry, with the test track and the 10 m radius around the centre formed of hard surface (concrete, asphalt or equivalent).
- Within a 50 m radius of the track centre there should be no large reflective objects (buildings, bridges, rocks, fences).
- Wind: measurements with mean wind speed at the microphone exceeding 5 m/s are invalid.
- Background noise (including wind noise) must be at least 10 dB below the noise produced by the moped under test.
Microphone position and geometry
- Microphone height: 1.2 m ± 0.1 m above ground.
- Distance from microphone to the reference line on the track: 7.5 m ± 0.2 m.
- Microphone axis should be horizontal and perpendicular to the moped path.
Measurement procedure and validity
- At least three valid passes on each side of the moped are required.
- Record the maximum A‑weighted sound pressure level (with F weighting) during each pass between defined track lines.
- Results for a side are valid if the difference between extreme values of three consecutive valid measurements does not exceed 2 dB.
- The test result is the higher of the two arithmetic means (one per side), rounded to the nearest 0.5 dB.
Vehicle preparation and operating conditions
- Moped must be in running order with recommended fuel, spark plug(s) and carburetor settings.
- Total test mass (rider, test equipment and ballast) is specified in the standard (example range given in the text: 70–80 kg).
- Tyres must be of the type normally fitted and inflated to the manufacturer’s recommended pressure.

Applications

Type approval testing for manufacturers and regulatory bodies
Production-line verification and factory conformance checks
Accredited laboratory or official station acoustic evaluations

Related Standards

ISO 4164 (vehicle engine power test code) - referenced for engine power-related data
ISO 6726 (vocabulary for mopeds and motorcycles)
IEC 651 (sound level meters) - instrument class and performance

ISO 9645:1990 PDF

Technical details

Abstract

Overview

Key Topics

Applications

Related Standards

Reporting and Practical Value

Related standards

Abstract

Overview

Key Topics

Applications

Related Standards

Reporting and Practical Value

Related standards

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