Noise from motor vehicles : interim report / Committee on the Problem of Noise.

  • Great Britain. Committee on the Problem of Noise
Date:
[1962]
Catalogue details

Licence: Public Domain Mark

Credit: Noise from motor vehicles : interim report / Committee on the Problem of Noise. Source: Wellcome Collection.

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    99 66 99 «66 various levels may be set corresponding to ‘ ‘noisy acceptable’, “ quiet”, &c., and according to the degree of “ protection ” required by the listeners, or the vehicles, or both. By way of illustration the case is considered in which the basic point on the subjective rating scale at which * protection ” is required is the demarcation between “acceptable ’”’ and “noisy”. Referring to Table III, this point is repre- sented by sound-levels of 79-5 dB, 80:5 dB and 82:5 dB (A) for petrol-engined vehicles, diesel-engined vehicles and motor-cycles respectively, and if no vehicle exceeded these sound-levels approximately half the listeners would judge them to be “just acceptable”. It is of interest to note that the average listener permits a slightly higher sound-level (A) for motor-cycles than for the other two classes of vehicles. If it is required to “ protect” all listeners then 12 dB (3c criterion) should be subtracted from (the basic levels quoted above resulting in sound-levels of 67-5 dB, 68-5 dB and 70-5 dB (A) respectively for the three classes of vehicles. On the other hand, if it is required that no vehicle is “penalised” by the shortcomings of the meter, then upward adjustments should be made to the basic levels amounting to 4 dB, 3 dB and 7 dB (A) Geo criterion) resulting in sound-levels of 83-5 dB, 83-5 dB and 89-5 dB (A) for petrol-engined vehicles, diesel-engined vehicles and motor-cycles respectively. | ACKNOWLEDGMENTS The authors wish to acknowledge tthe assistance of their colleagues, in particular Messrs. W. C. Copeland and J. C. Dixon, who carried out the experimental work, and Mr. L. Verra, Mathematics Division, National Physical Laboratory, who carried out the numerical analysis. They also acknowledge the assistance of subjects who took part in the listening tests, and of Mr. Rayner of the National Coal Board who made a number of his staff available for this purpose. The work described forms part of the research programme of the Motor Industry Research Association, and iof the Applied Physics Division, National Physical Laboratory, and the article is published by permission of the Directors of these bodies. REFERENCES 1 Robinson, D. W., Copeland, W. C., and Rennie, A. J. THe ENGINEER, March 31, 1961, Vol. 211, No. 5488, pages 493-97. 2 Generaldirektion P.T.T. Switzerland, Forschungs und Versuchsanstalt Report No. 22637 and Appendix, October, 1959. 3 Andrews, B., and Finch, D. M., “‘ Truck Noise Measurement,’ Proc. Highways Research Board (U.S.A.), December, 1951, pages 456-65. 45 (32422) Wt. 335-63 K40 7/62 St.S.
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