without the use of individual protective devices. When the latter are used, the allowable levels of noise may be correspondingly increased by ten decibels.
1.5.130(55568) Corlett, E. N., Moreombe, V. J. and Chanda, B. Shielding factory noise by work-inprogress storage Applied Ergonomics, 1970, 1.2, 73-78
1.5.128(55566)
Studies in several open machine shops equipped with large numbers of noisy machines suggest that although any one machine may n o t be excessively noisy, the combination of m a n y in a reverberating environment causes a 'standing peak' of noise at an unacceptable level. Suitably placed barriers with slight attenuating properties may thus be enough to reduce the high noise peaks to tolerable limits. Case studies showing the effects of stacks of work-inprogress on noise levels are described in in this article and an indication is given of how computer simulation can be used to decide on the layout of a factory incorporating such noise barriers.
Society of Automotive Engineers, Inc. A study of noise induced hearing damage risk for operators o f farm and construction equipment Abstr. in US Government Research and Development Reports (Report No P B - 188633) Most noise criteria for evaluating hearing damage risk have been derived from industrial environments where noise is assumed constant, where daily exposures are uninterrupted, and where conditions are repeated on an almost daily basis. Such criteria are not directly applicable to evaluation of hearing damage risk for operators of farm and construction equipment. An analysis of hearing loss criteria is presented regarding their applicability to both continuous and intermittent noise. In addition, a review is made of their derivation and applicability to the agricultural and construction noise environments. Acoustical data are also presented for various pieces of equipment to both establish existing levels and define the types of data which axe necessary to evaluate properly a noise environment. Available noise data are then applied to several criteria to illustrate the techniques involved and possible hazard to hearing from such noise dosage.
The extent of external noise in the urban environment is discussed with particular reference to road traffic and aircraft. T h e influence of noise on the thermal environment inside buildings is considered in general terms. Then, as an example o f specific treatment of buildings against noise, the recommendations of the Wilson Committee and their implementation for houses near London Airport are outlined. The results of BRS studies which formed the basis of these sound insulation and ventilation recommendations are summarised. The paper concludes with some further comments on ventilation in soundprotected houses and emphasises the need for further research.
Vibration 1.5.134(55572)
1.5.131(55569)
Ketchel, J. M., Donaher, J. W. and
Dawanee, G., Sequin, M. and
Morrissey, C. J. Effects o f vibration on navy and marine corps helicopter flight crews Abstr. in US Government Research and Development Reports (No A D - 698194)
Marseille, B. et al. Noise and vibration problems affecting dwellings in industrial zones (In French with English summary) Revue d'Acoustique, 1969, 2. 7, 207-210; abstr, in Building Science Abstracts Describes effects on adjacent buildings of noise and vibration originating from factories. Measures to minimize the discomfort caused to the inhabitants are outlined.
1.5.132(55570) 1.5.129(55567) Wise, A. F. E. Buildings in noisy areas, interaction of acoustic and thermal design Building Research Station, Current Papers 43/69, 1969; abstr, in Building Science Abstracts
exposure in these units are effectively measurements or predictions o f nuisance. Such units are developed by means of social surveys, and typical survey techniques are briefly described. Of the three current proposals: Wilson Proposals, Traffic Noise Index, and Mean Energy Level, the Wilson Proposals fail the requirements of a physical unit intended to be the basis of traffic noise control because o f the lack of demonstrated correlation of noise levels with nuisance. Both Traffic Noise Index and Mean Energy Level have been shown to correlate well with nuisance b u t nevertheless t h e formulations of these two units are, in some respects conflicting. The development and the relative merits of the two units are discussed, and the direction of further research into traffic noise is outlined.
Anon. Reduction of weaving noise: one practical experiment (In French) Industrie Textile. 1969, 982, 417-418; abstr, in World Textile Abstracts A sound-absorbent ceiling covered with mineral-wool panels was shown to go some way to alleviating noise problems in a shed with 84 Jacquard and 36 conventional looms. An operative is claimed to hear only the noise of the machine in front of him and not to be conscious of the general r o o m noise level. 1.5.133(55710) Seholes, W. E. Traffic noise criteria Building Research Station, Current Papers 38/69, 1969. Abstr. in Building Science Abstracts Traffic noise needs to be described in physical terms such that measurements or predictions of noise
Identifiable vibration characteristics of c o n t e m p o r a r y military helicopters are described. These provide a basis for analysing and interpreting the literature on vibration research. Emphasis is given to experimental results which relate to frequencies and acceleration amplitudes falling within the helicopter main r o t o r effects region. The spectrum of military helicopters is tabulated briefly and six representative Navy/Marine Corps helicopters, missions and associated flightcrew tasks are described in more detail. Perceptual-motor behaviours comprising crew tasks in the six missions are identified. These are used to relate vibration analysis results to the helicopter situation. 1.5.135(55573) Frey, A. H. Effects of microwaves and radio frequency energy on the central nervous system Abstr. in US Government Research and Development Reports (Report No A D - 698195) The history of research in this area is briefly sketched, sources of misunderstanding and confusion are identified, the writer's own experimentation is briefly outlined, and critical matters that an experimenter must recognise are defined.
Applied Ergonomics December 1970
313