ISO/TC 43/SC 1/WG 42 - Joint ISO/TC 43/SC 1 - ISO/TC 22 WG: Measurement of noise emission (external) from road vehicles

This document specifies a test procedure, environment and instrumentation for measuring the exterior sound pressure levels from road vehicles under stationary conditions, providing a continuous measure of the sound pressure level over a range of engine speeds. This document applies only to road vehicles of categories L, M, and N equipped with internal combustion engines. Vehicles where an internal combustion engine cannot operate when the vehicle is at stationary conditions are outside the scope of this document. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. It is within the scope of this document to measure the stationary A-weighted sound pressure level during — type approval measurements of vehicle; — measurements at the manufacturing stage; — measurements at official testing stations; — measurements at roadside testing. This document specifices a test method to determine a reference sound level which is unique for the vehicle and therefore not suitable to compare against a general limit, as test condition, microphone condition location relative to the sound sources can vary significantly. The test conditions in proximity and at engine speeds significantly higher compared to real operation conditions in traffic are deliberately chosen to enable in-use tests at higher background conditions, which are typical for road-side checks. Technical background information is given in Annex A.

ISO 362-3:2016 specifies an engineering method for measuring the noise emitted by road vehicles of categories M and N by using a semi anechoic chamber. The specifications are intended to achieve an acoustical correlation between testing the exterior noise of road vehicles in a semi anechoic chamber and outdoor testing as described in ISO 362-1. ISO 362-3:2016 provides all necessary specifications and procedures for indoor testing to obtain results which are comparable to typical run-to-run variations of measurements in today's type approval tests. It provides a method designed to meet the requirements of simplicity as far as they are consistent with the reproducibility of results under the operating conditions of the vehicle. NOTE 1 The results obtained by this method give an objective measure of the noise emitted under the specified conditions of test. It is necessary to consider the fact that the subjective appraisal of the noise annoyance of different classes of motor vehicles is not simply related to the indications of a sound measuring system. As annoyance is strongly related to personal human perception, physiological human conditions, culture, and environmental conditions, there is a large variation and annoyance is therefore not useful as a parameter to describe a specific vehicle condition. NOTE 2 If measurements are carried out in rooms which do not fulfill the requirements stated in ISO 362-3 :2016, the results obtained can deviate from the results using the specified conditions.

ISO 16254:2016 is derived from ISO 362‑1 and specifies an engineering method for measuring the sound emitted by M and N category road vehicles at standstill and low speed operating conditions. The specifications reproduce the level of sound which is generated by the principal vehicle sound sources consistent with stationary and low speed vehicle operating conditions relevant for pedestrian safety. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustic environment which is only obtained in an extensive open space. Such conditions usually exist during the following: - measurements of vehicles for regulatory certification; - measurements at the manufacturing stage; - measurements at official testing stations. The results obtained by this method give an objective measure of the sound emitted under the specified conditions of test. It is necessary to consider the fact that the subjective appraisal of the annoyance, perceptibility, and/or detectability of different motor vehicles or classes of motor vehicles due to their sound emission are not simply related to the indications of a sound measurement system. As annoyance, perceptibility and/or detectability are strongly related to personal human perception, physiological human condition, culture, and environmental conditions, there are large variations and therefore these terms are not useful as parameters to describe a specific vehicle condition. Spot checks of vehicles chosen at random rarely occur in an ideal acoustic environment. If measurements are carried out on the road in an acoustic environment which does not fulfil the requirements stated in this International Standard, the results obtained might deviate appreciably from the results obtained using the specified conditions. In addition, this International Standard provides an engineering method to measure the performance of external sound generation systems intended for the purpose of providing acoustic information to pedestrians on a vehicle's operating condition. This information is reported as objective criteria related to the external sound generation system's sound pressure level, frequency content, and changes in sound pressure level and frequency content as a function of vehicle speed. As such, these measures can provide pedestrians with information on the location, speed, acceleration, and deceleration behaviour of a vehicle. Annex A contains background information relevant in the development of this International Standard.

ISO 362-1:2015 specifies an engineering method for measuring the noise emitted by road vehicles of categories M and N under typical urban traffic conditions. It excludes vehicles of category L1 and L2, which are covered by ISO 9645, and vehicles of category L3, L4, and L5, which are covered by ISO 362‑2. The specifications are intended to reproduce the level of noise generated by the principal noise sources during normal driving in urban traffic. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustical environment that is obtained only in an extensive open space. Such conditions are usually provided for ? type approval measurements of a vehicle, ? measurements at the manufacturing stage, and ? measurements at official testing stations.

ISO 10844:2014 specifies the essential characteristics of a test surface intended to be used for measuring vehicle and tyre or road noise emissions. The surface design given in ISO 10844:2014 produces consistent levels of tyre or road sound emission under a wide range of operating conditions including those appropriate to vehicle sound testing, minimizes inter-site variation, provides minor absorption of the vehicle sound sources, and is consistent with road-building practice.

ISO 362-2:2009 specifies an engineering method for measuring the noise emitted by road vehicles of categories L3, L4 and L5 under typical urban traffic conditions. It excludes vehicles of category L1 and L2, which are covered by ISO 9645, vehicles of categories M and N covered by ISO 362-1 and vehicles of categories L6 and L7. The specifications are intended to reproduce the level of noise generated by the principal noise sources during normal driving in urban traffic, typically on roads with speed limits of 50 km/h and 70 km/h. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustical environment that is only obtained in an extensive open space. Such conditions are usually provided for type approval measurements of a vehicle, measurements at the manufacturing stage and measurements at official testing stations.

ISO 10844:2011 specifies the essential characteristics of a test surface intended to be used for measuring vehicle and tyre/road noise emissions. The surface design given in ISO 10844:2011: a) produces consistent levels of tyre/road sound emission under a wide range of operating conditions including those appropriate to vehicle sound testing; b) minimizes inter-site variation; c)provides minor absorption of the vehicle sound sources; d) is consistent with road-building practice.

ISO 362-1:2007 specifies an engineering method for measuring the noise emitted by road vehicles of categories M and N under typical urban traffic conditions. It excludes vehicles of category L1 and L2, which are covered by ISO 9645, and vehicles of category L3, L4 and L5 covered by ISO 362-2. The specifications are intended to reproduce the level of noise generated by the principal noise sources during normal driving in urban traffic. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustical environment that is only obtained in an extensive open space. Such conditions are usually provided for type approval measurements of a vehicle, measurements at the manufacturing stage, and measurements at official testing stations.

ISO 5130:2007 specifies a test procedure, environment and instrumentation for measuring the exterior sound pressure levels from road vehicles under stationary condition, providing a continuous measure of the sound pressure level over a range of engine speeds. ISO 5130:2007 applies only to road vehicles of categories L, M and N equipped with internal combustion engines. ISO 5130:2007 is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. It is within the scope of ISO 5130:2007 to measure the stationary A-weighted sound pressure level during type approval measurements of vehicle, measurements at the manufacturing stage, measurements at official testing stations and measurements at roadside testing. Technical background information is provided. ISO 5130:2007 specifies neither a method to check the exhaust sound pressure level when the engine is operated at realistic load nor a method to check the exhaust sound pressure levels against a general noise limit for categories of road vehicles.