Noise - 2,325 entries found

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1974

CIS 75-982 Frenking H.
Noise studies with construction machinery to determine the level of noise at the workplace and the state of technology
Geräuschuntersuchungen an Baumaschinen zur Feststellung der Lärmeinwirkung am Arbeitsplatz und zur Ermittlung des Standes der Technik [in German]
A study carried out with the financial aid of the Commission of the European Communities to investigate the noise conditions near construction machinery in normal use. The state of technology was defined as a criterion by which to distinguish between avoidable and unavoidable noise. The following equipment was studied: portable compressors, power shovels, wheeled loaders, bulldozers, track-mounted loaders, various compactors, concrete mixers, truck mixers, concrete pumps. The modes of operation described and the results presented in table and diagram form show that it is not possible to correlate exposure time with the noise levels measured to yield general characteristic values for workplaces, on account of the varied uses to which the machines are put.
Forschungsbericht Nr.122, Bundesanstalt für Arbeitsschutz und Unfallforschung, Martener Strasse 435, 46 Dortmund-Marten, Germany (Fed.Rep.), 1974. 77p. Illus. 25 ref. Price: DM.10.40.

CIS 75-1151 Towards a healthy working environment - First report of the Joint Standing Committee on Health and Welfare in the Cotton and Allied Fibres Industry, 3rd April 1973.
Results of enquiries into existing conditions concerning dust, thermal environment and noise in cotton mills of the United Kingdom. The following recommendations are formulated in a summary: total cotton dust less fly not exceeding 0.5mg/m³ in workrooms where cotton is processed; determination of airborne dust concentration at least once per year; dust and noise control measures at cotton-processing machines; corrected effective temperature of 22°C; ventilation and air recirculation; no continuous exposure to sound levels in excess of 90dBA; personal protection. Results of dust sampling, thermal conditions and noise measurements in cotton spinning mills are tabulated in appendices.
Department of Employment, H.M. Stationery Office, P.O. Box 569, London S.E.1, United Kingdom, 1974. 35p. Illus. 11 ref. Price: £0.50.

CIS 75-981 Suwalski R.
Method of measuring sound transmission of lightweight walls in the reverberant field of 3.15-40kHz wave frequencies
Metoda pomiarów izolacyjności akustycznej lekkich przegród w polu fal rozproszonych o częstotliwości 3,15-40kHz [in Polish]
The author describes in detail a method of measuring the specific sound isolation of lightweight walls subjected to a reverberant field, based on International Recommendation ISO R 140. In view of the frequency range adopted for the sound waves (3.15-40kHz), the conditions of measurement differed from those established in the recommendation, especially as regards the dimensions of the measurement chamber and the characteristics of the wave source. From the satisfactory agreement between the theoretical and experimental values, the authors recommend applying the method described to model studies of the optimum characteristics of simple and double walls intended for the construction of enclosures for ultrasound installations.
Prace Centralnego instytutu ochrony pracy, 1974, Vol.24, No.82, p.209-228. Illus. 13 ref.

CIS 75-980 Augustyńska D.
Results of research on silencers for ventilation installations
Z badań nad tłumikami akustycznymi do instalacji wentylacyjnych [in Polish]
The author describes the method of calculating parameters for absorption silencers and outlines the principles of 4 recently designed prototypes. He compares the attenuation characteristics of these prototypes, calculated from various formulae, with the values measured in a testing unit without an air flow, specially designed at the Polish Central Institute for Workers' Protection (CIOP): the values obtained with the formulae and nomograms derived from Lenk's theory are the best approximation for the study of silencers. The prototypes presented were found to be effective and their mass production is under consideration. The methodology adopted for this research can serve as a basis on which to establish a standard for the study of absorption silencers for industrial ventilators.
Prace Centralnego instytutu ochrony pracy, 1974, Vol.24, No.82, p.187-208. Illus. 21 ref.

CIS 75-1187 Hadjiolova I.
Changes in the plasma and suprarenal corticosterone levels in rats during hypokinesia and additional stress
Veränderungen des Plasma- und Nebennierenrindencorticosterons bei Ratten während Hypokinesie und zusätzlicher Stress-Einwirkungen [in German]
The decrease of muscle impulse as a result of limited motor activity in vigilance tasks is considered to be a stress factor, activating the hypophysis-suprarenal system. The changes in plasma and suprarenal corticosterone levels in rats were examined at various intervals during prolonged hypokinesia. Suprarenal cortex activity was also studied after additional thermal stress and after acute and chronic exposure to noise. A moderate increase in the levels of both plasma and suprarenal corticosterone was observed after 24h of hypokinesia. During the following 60 days, the corticosterone levels did not differ significantly from the levels found in controls. However, a marked decrease in suprarenal weight and a more discrete response to additional thermal stress were demonstrated after 60 days of hypokinesia. Differences between restrained and control animals were also found in adaptation to chronic auditory stress.
Internationales Archiv für Arbeitsmedizin - International Archives of Occupational Health, 12 Mar. 1974, Vol.33, No.1, p.59-70. Illus. 22 ref.

CIS 75-979 Popeck R.A.
Occupational noise exposure problem areas in power plants.
Procedures and equipment used successfully in a power plant to establish compliance with occupational noise regulations are described: A-scale survey of the plant, personnel exposure, identification and characterisation of sound sources. Noise levels of typical power plant noise generators are listed, and sound spectra of noise sources presented. The results show that specific noise sources can be identified with the aid of noise spectra. General observations are formulated concerning noise exposure reduction.
Sound and Vibration, June 1974, Vol.8, No.6, p.28-33. Illus.

CIS 75-978 Johnson D.L., Nixon C.W.
Simplified methods for estimating hearing protector performance.
Three methods for estimating the noise attenuation effectiveness of hearing protectors are described and evaluated, using typical noise spectra and attenuation data of 33 different protector systems (25 earmuffs, 5 combinations of earplugs and earmuffs, 3 earplugs): NIOSH/OSHA short method; Botsford short method; 2-number method. Noise spectra, hearing protector data and results of the calculations are listed in tables. It is recommended that the Botsford method with a 6dB safety factor be promoted as the best simplified method for evaluating hearing protector performance.
Sound and Vibration, June 1974, Vol.8, No.6, p.20-27. Illus. 6 ref.

CIS 75-973 De Montille G.
Noise in industry and noise measurement
L'acoustique industrielle et les mesures du bruit. [in French]
Essential data on noise and its measurement: sound intensity (sound pressure level, addition of 2 noises); sound spectrum (sensitivity of the ear, weighting curves, frequency band analysis, hearing damage criteria); equivalent steady state noise and time constants. Basic definitions are set out separately from the text. The article emphasises the possibilities of noise measurement without sophisticated equipment. List of French and ISO standards on noise.
CETIM Informations, Apr. 1974, No.35, p.17-24. Illus. 12 ref.

CIS 75-1122 Walton W.H.
Mining: Problems and progress in industrial hygiene.
Text of the 1971 Yant Memorial Lecture, updated by a short addendum. The main safety and health hazards in mines are reviewed, special attention being devoted to the problems presented by airborne dust (epidemiological surveys, dust sampling, dust standards, etc.) and noise.
American Industrial Hygiene Association Journal, Jan. 1974, Vol.35, No.1, p.1-12. 49 ref.

CIS 75-972 Liénard P.
Decibels and noise factors - Various methods of measuring sound levels, annoyance and harmful effects due to noise, using physical measurements
Décibels et indices de bruit - Diverses méthodes d'évaluation des niveaux sonores, gêne et nuisance dues au bruit à partir de mesures physiques. [in French]
After a reminder that the decibel is not a unit, but a way of counting which can be applied to any quantity, the author of this booklet studies the physical measurements of a source of noise (sound pressure level, acoustic power), so-called subjective measurements, assessment of annoyance or harmful effects of steady-state noise, and influence of noise duration or other parameters. Index of commonly used units.
Masson, 120 Boulevard St-Germain, 75006 Paris, France, 1974. 50p. Illus. 55 ref. Price: FF.25.00.

CIS 75-970 López Cristobal J.A.
Sound-proofing of a motor test bed
Insonorización de un banco de pruebas de motores [in Spanish]
Description of the sound-proofing measures undertaken in a 500m² workshop comprising 30 repair and assembly benches for powerful electric motors used in mining machinery, in which an extremely noisy test bed, which completely transformed the acoustic microclimate of the workshop, was installed. Measures taken: sound screens, full enclosure, ventilation. Result: the level of noise in the workshop was lower than before installation of the test bed.
Revista Seguridad, Apr.-June 1974, No.53, p.45-48. Illus.

CIS 75-969 Dieroff H.G.
Hearing impairment due to impulse noise
Gehörschädigender Impulslärm [in German]
A general review of the frequency of hearing loss by impulse noise in the metal, mining and construction industries is followed by a discussion of the problem of total noise load evaluation, illustrated by the case of bolt gun noise. It is concluded that impulse noise causes mechanical destruction of the hair cells in the Corti organ, whereas hearing loss due to permanent noise exposure is merely the result of metabolic overload. Ear protectors should therefore be worn when using a bolt gun.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, Apr. 1974, Vol.20, No.4, p.215-218. Illus. 9 ref.

CIS 75-967
Unfallverhütungsvorschrift, Federation of Industrial Mutual Accident Insurance Associations (Hauptverband der gewerblichen Berufsgenossenschaften), Bonn, 1. Dec. 1974.
Noise
Lärm [in German]
These regulations, which entered into force on 1 Dec. 1974, apply to all plants where persons are working in conditions of ambient noise. They cover the following aspects: employer's obligation to reduce noise levels, to provide individual hearing protection, to prevent hearing loss and accidents due to noise, to post warning notices of zones where there is a noise hazard, to provide for preventive and periodic medical examinations, to notify accidents and hearing injury, and to keep records.
Carl Heymanns Verlag KG, Gereonstrasse 18-32, 5 Köln 1, Germany (Fed.Rep.). 7+ 10p. Price: DM1,05.

CIS 75-966 Noise characteristics of fans
Geräuschverhalten von Ventilatoren [in German]
The principal terms (sound pressure level and sound power level) are explained and mathematically defined, and the noise production of fans is analysed. The main part of this brochure deals with: measurement of the sound power level of fans; the choice of fans according to acoustic features and noise control measures at their installation; vibration and smooth running. The mode of calculation of the total sound power level is shown in the annex.
VEB Turbowerke Meissen, Niederauer Strasse 26-28, x 825 Meissen, German Democratic Republic, no date. 25p. Illus. 10 ref.

CIS 75-965 Költzsch P.
Noise reduction at compressed-air nozzles
Lärmminderung an Druckluftdüsen [in German]
Measures recommended in the literature for noise reduction at nozzles are listed, and experiments with 60 different types of nozzles are described. A minimum of sound power and energy expenditure combined with the blowing force required for the technical application was the criterion used. Ring-hole, multiple-hole and multiple-tube nozzles showed the best results; the sound power level could be reduced by 10dB(A) with the most favourable nozzle designs.
Fertigungstechnik und Betrieb, Feb. 1974, Vol.24, No.2, p.102-107. Illus. 9 ref.

CIS 75-964 Capellini A., Maroni M.
Clinical research on arterial hypertension and coronary disease and their possible link with the working environment in a chemical plant
Indagine clinica sull'ipertensione arteriosa e la malattia coronarica e loro eventuali rapporti con l'ambiente di lavoro in operai di un'industria chimica [in Italian]
As part of the general research effort to ascertain the causes of possible occupation-induced cardiovascular disease, 1,346 workers employed in a chemical plant in Northern Italy were examined (medical background, radiography, ECG, clinical tests). The frequency of cardiovascular disorders and hypertension was established in relation to: 4 different age groups, various factors such as working hours, etc. and noise. Statistical analysis of the data showed that workers exposed to loud noise (85-95dB) had a tendency to ischaemic heart disease corresponding to an age bracket 10 years older than their real age. The authors suggest that intense noise may disturb homeostasis.
Medicina del lavoro, July-Aug. 1974, Vol.65, No.7-8, p.297-305. Illus. 9 ref.

CIS 75-698 Himmler C.R.
Attenuation of noise from hydraulic pumps
Réduction du bruit engendré par les pompes hydrauliques. [in French]
Translation of: Zur Frage der Geräuschminderung von Hydraulikpumpen. Ölhydraulik und Pneumatik, Mainz, Germany (Fed.Rep.), 1970, Vol.14, No.4, p.137-141. Illus. 6 ref. Noise from hydraulic pumps has several origins: inequalities of volume and pressure, variations in load and flow, elastic vibrations, etc. The author describes the apparatus used for noise measurement and proposes various noise and vibration damping methods (construction of casing, silencers, etc.).
Traduction INRS 7 B-74, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1974. 17p. Illus. 6 ref.

CIS 75-696 Gurevič H.A., Korzunov Ju.L., Kuščev Ju.D., Mitjuškin Ju.I.
Study of acoustic and vibration characteristics of a single-stage reaction turbine with non-radial fixed blades
Issledovanie vibroakustičeskih harakteristik odnostupenčatoj reaktivnoj turbiny s neradial'nym raspoloženiem napravljajuščih lopatok [in Russian]
It has now been confirmed that the tangential inclination of fixed blades efficiently contributes to the reduction of dynamic stresses on the moving blades of axial-flow turbines and that, in the case of axial-flow fans, the non-radial arrangement of the fixed blades reduces the noise level. This article gives the results of studies on the vibration, acoustic and aerodynamic behaviour of stages of reaction turbines equipped with moving blades without curvature. These studies demonstrated the advantages of a moderately tangential slope of the fixed blades, resulting in a considerable reduction of aerodynamic noise and vibrations in single-stage reaction turbines.
Energomašinostroenie, Mar. 1974, No.3, p.9-10. Illus. 11 ref.

CIS 75-691 Proceedings of the Symposium on noise.
This symposium, held in Pittsburgh, Pennsylvania, USA, on 9-10 Oct. 1973, was designed to offer a forum for the views of government, industry, labour and the scientific community on noise exposures and the standards under which they will be regulated. It includes papers on: medical aspects of hearing loss due to noise; various considerations on standards; special problems of noise exposure in the textile industry; inter-industry noise study; temporary threshold shift; hearing conservation programmes; audiometric testing; noise dosimeter performance; noise control; acoustic network theory; sound and vibration frequency analysis; etc.
Industrial Health Foundation, 5231 Centre Avenue, Pittsburgh, Pennsylvania 15232, USA, 1974. 158p. Illus. 21 ref.

CIS 75-689 Yerges L.F.
Cost/effectiveness approach to machinery noise control.
Loss in production or the cost of noise control devices and methods eliminate many approaches to noise control. Examples are given of simple measures for noise control at the source, along the transmission path, and at the machine operator's workpost. A rough cost/benefit analysis in tabular form shows that machine enclosures and worker shelters are the most expensive solutions.
Sound and Vibration, July 1974, Vol.8, No.7, p.30-32. Illus.

CIS 75-688 Macduff J.N.
Barriers for noise control.
After introductory remarks on prediction methods for attenuation, a system of noise abatement in a refrigerator compressor room by the use of screens is reported. The design of test enclosures is described; the results of indoor and outdoor attenuation tests are shown in diagrams and discussed. Conclusions are drawn concerning the design of the enclosure and the value of the methods for the prediction of attenuation. The noise reduction of an enclosure is improved if a partial or full top can be provided.
Mechanical Engineering, Aug. 1974, Vol.96, No.8, p.26-31. Illus. 13 ref.

CIS 75-687 MacWhorter R.F.
Gear noise source identification and reduction.
The paper deals primarily with noise generated by small manufacturing inaccuracies in large high-speed gears. Solutions to noise problems of this type involve corrective action other than rehobbing or refinishing. The noise transmission path from the mesh to the receiver is outlined, and methods of source identification are described. An example of a typical investigation from identification of the source down to confirmation of the effectiveness of the control measures adopted is presented in detail.
American Industrial Hygiene Association Journal, Sep. 1974, Vol.35, No.9, p.581-585. Illus.

CIS 75-686 Schmidek M., Carpenter P.
Intermittent noise exposure and associated damage risk to hearing of chain saw operators.
A survey of the noise exposures experienced in thinning forested areas is reported. Observations were made in 10 chain saw operators using 5 different models of saw. Types of intermittent exposure, temporary threshold shifts and subsequent recovery rates are dealt with, and the findings are reviewed in the light of proposed U.S. standards for intermittent noise: by this criterion, the level of noise exposure was hazardous. Individual cutting style was found to be more significant for noise production than the model or size of saw used. It is concluded that this sawing operation does present a risk to hearing, but not as great as the level of noise exposure would seem to indicate.
American Industrial Hygiene Association Journal, Mar. 1974, Vol.35, No.3, p.152-158. Illus. 4 ref.

CIS 75-680 Rentzsch M.
Noise measurement and measures to be taken to reduce noise in driver's cabs of transport vehicles and earthmoving equipment
Mesure du bruit et dispositions à prendre pour réduire le bruit dans les cabines de conduite des engins de transport et des engins de chantier. [in French]
Translation of: Geräuschmessungen und Massnahmen zur Lärmminderung in Fahrerkabinen von Förder- und Baumaschinen. Hebezeuge und Fördermittel, Berlin (Ostsektor), Dec. 1969, Vol.9, No.12, p.365-368. Illus. 5 ref. Taking as example a UB 20 excavator manufactured in Eastern Germany, the author studies the phenomenon of noise transmission from source (engine, gearbox, etc.) to driver's cab and analyses the noise (airborne or structure borne) in the cab, and examines various noise abatement measures on a reduced-scale model cab: antivibration coating, porous absorbent. As the efficacy of these measures was apparent only at 250kHz or more, the article stresses the necessity for improving the insulation of the sources of noise already at the machine construction stage.
Traduction INRS 6 B-74, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1974. 11p. Illus. 5 ref.

CIS 75-676 Waugh R.
Pure-tone, third-octave, and octave-band attenuation of ear protectors.
The difficulties in measuring ear-protector attenuation are stressed; third-octave bands of noise appear to offer a solution to the problem. Experimental work is reported comparing pure-tone and third-octave band measurements of attenuation, calculating octave from third-octave attenuation, and finally comparing the octave-band values so calculated with pure-tone attenuation values. It is concluded that for practical purposes pure-tone and third-octave-band measurements of ear-protector attenuation are identical. The use of pure-tone attenuation values at octave-band centre frequencies as estimates of octave-band attenuation can lead to errors of more than 10dB. In the octaves centred at 500Hz and above, ear-protector attenuation should be measured at third-octave centre frequencies.
Journal of the Acoustical Society of America, Dec. 1974, Vol.56, No.6, p.1866-1869. Illus. 7 ref.

CIS 75-675 Klosterkötter W.
New findings on the effects of noise
Neuere Erkenntnisse über Lärmwirkungen [in German]
The autonomic reactions to noise, as determined by measurement of the finger pulse and skin resistance, are extremely variable. On the basis of other findings and his own work, the author concludes that the classification of noise proposed by Lehman is no longer tenable. Given the present state of knowledge, he warsns against the tendency to apply average limit values obtained in the laboratory to industrial situations. Finally, the criteria for traffic noise limitation are compared with those for industrial noise.
Kampf dem Lärm, Aug. 1974, Vol.21, No.4, p.103-111. Illus. 30 ref.

CIS 75-674 Leskov Ė.A., Medencov L.F.
Low-frequency baffle silencers
Nizkočastotnye plastinčatye glušiteli [in Russian]
Results of studies on silencers incorporating a thick sound absorbent for attenuation of low-frequency noise from ventilation or air-conditioning systems. These baffle silencers have a better attenuation power than honeycomb silencers for frequencies below 250Hz.
Vodosnabženie i sanitarnaja tehnika, Mar. 1974, No.3, p.24-27. Illus. 10 ref.

CIS 75-672
Federation of Industrial Mutual Accident Insurance Associations (Hauptverband der gewerblichen Berufsgenossenschaften), Bonn, Feb. 1974.
Principles applicable to preventive medical examinations - Hearing damage hazard from noise
Berufsgenossenschaftliche Grundsätze für arbeitsmedizinische Vorsorgeuntersuchungen - Gehörgefährdung durch Lärm [in German]
Principles laid down as a guideline for plant physicians for early detection of hearing damage due to noise, and hearing conservation. These principles mainly concern pre-employment aptitude examinations and periodic check-ups, and cover the following points: sound pressure levels which constitute a hearing damage hazard, sources of hazard, process of hearing damage, pathology, procedure for audiometric examinations. A commentary on these principles, by Bernhardt H., appears on pages 186-190 (Illus. 6 ref) of the same issue; the author advises physicians to exercise great caution in carrying out pre-employment examinations to determine whether a person should be allowed to work in a noisy environment; he considers the influence of "silence breaks" prior to audiometric examinations and advocates electronic data processing of findings.
Arbeitsmedizin - Sozialmedizin - Präventivmedizin, Sep. 1974, Vol.9, No.9, p.190-194. 9 ref.

CIS 75-385 Schreiner L., Eder H.
Noise surveys and exposure tests in the metallurgic industry
Lärmuntersuchungen und Expositionstests in der Metallindustrie [in German]
Survey on the course of hearing loss in 50 workers employed in forging and fettling shops, exposed to noise of varying spectral composition. The results of noise measurements and audiometric examinations are commented upon with diagrams. The authors deprecate the performance during the workshift, i.e. in a condition of impaired hearing, of audiometric investigations intended to determine the long-term course of hearing loss. A temporary threshold shift does not necessarily lead to a permanent shift of the same magnitude after several years' exposure to noise. The evolution curves of hearing loss due to noise point clearly to a saturation at the 500Hz and 4kHz frequency ranges after 15 years' exposure. Hearing loss at 2kHz, however, continues to worsen after this time, i.e. there is a progressive widening of the 4kHz dip.
Zentralblatt für Arbeitsmedizin und Arbeitsschutz, May 1974, Vol.24, No.5, p.148-153. Illus. 8 ref.

CIS 75-384 Pietruck S., Ringer F.
Noise at the workplace
Lärm am Arbeitsplatz [in German]
Since the improvements in the compensation system and measurement techniques in the 'sixties, a great increase in the incidence of occupational deafness has been noted in the German Federal Republic. Statistics and graphs published by the Mutual Accident Insurance Association for the Chemical Industry (Berufsgenossenschaft Chemie) and data furnished by a tube-rolling mill illustrate this development. The authors report on measurements of noise made in this factory and audiometric examinations undergone by 609 workers, and present several audiograms showing the characteristic course of hearing loss. These audiograms show that the first signs of hearing injury appear after 10 years' exposure. Periods of 10-20 years elapsed before the audiogram showed a marked dip at 4,000Hz.
Zentralblatt für Arbeitsmedizin und Arbeitsschutz, May 1974, Vol.24, No.5, p.139-148. Illus. 4 ref.

CIS 75-383 Kilp K.H.
Evaluation and abatement of noise in the sheet-metal converting industry
Geräuschbeurteilung und Lärmminderung beim Umformen von Blech [in German]
A short consideration of the relation between the sound power and the noise-producing forces in an operating press is followed by a review of active (design) and passive (protection) measures for noise abatement in sheet-metal converting: modification of gear transmissions, damping of structure-borne noise, reduction of control gear and operating noise; damping and anti-drumming measures in transport tasks; enclosures and use of sandwich sheet metal.
Zeitschrift für industrielle Fertigung, 1974, Vol.64, p.549-553. Illus. 8 ref.

CIS 75-382 Rotthaus D.
Physical principles of noise control at presses
Physikalische Grundlagen der Lärmbekämpfung an Pressen [in German]
The acoustic pressure developed by the impact of the tool generally exceeds the critical threshold of 90dB(A). The author uses a simple physical model of noise production at presses to examine the theoretical possibilities of noise abatement. He establishes a quantitative relationship between the spectral distribution of the amplitude density of the work force impulse motivating the press, which gives rise to the noise, and the spectral distribution of the amplitude density of the resulting sound impulse. A characteristic of the machine, this relationship is expressed as the "sound power spectrum in relation to the force". This characteristic allows the nature of the noise pattern of different machines to be compared, and the effect of measures to reduce noise to be evaluated. The subsystems of which the noise transmission path is composed are studied in detail.
VDI-Z, May 1974, Vol.116, No.7, p.511-518. Illus. 19 ref.

CIS 75-381 Miller J.D.
Effects of noise on people.
An overview of the effects of noise on humans as they can be determined from the scientific literature. Only audible noise is considered. The effects of noise are classified as auditory, psychological and sociological, and physiological. While it is demonstrated that noise can adversely affect the quality of human life, possibly increasing man's susceptibility to disease, the only conclusively established effect of noise on health is that of noise-induced hearing loss.
Journal of the Acoustical Society of America, Sep. 1974, Vol.56, No.3, p.729-764. Illus. 122 ref.

CIS 75-380 Pelmear P.L., Hughes B.J.
Self-recording audiometry in industry.
A study of 118 drop-forge employees using fixed frequency self-recording audiometry showed that the mean of the differences at the test frequencies 0.5,1,2,3,4 and 6kHz ranges from -0.47dB to +0.61dB. The largest standard deviation was 6dB at 6kHz and the lowest 3dB at 2kHz. The results confirmed that temporary threshold shifts may be minimised if subjects are tested at the beginning of a shift or within 2h provided muffs were worn up to the time of the test. The results in this study support the view that the use of occupational health nurses with self-recording audiometers is a satisfactory method of audiometric screening in hearing conservation programmes.
British Journal of Industrial Medicine, Oct. 1974, Vol.31, No.4, p.304-309. Illus. 8 ref.

CIS 75-379 Hill V.H.
Noise control of high volume gas handling plants.
The major sources of noise in large-volume gas-handling plants (compressors and adjacent pipes, pressure-reducing valves, electric motors, high-speed drive gears, oil and gas burners, steam turbines) are briefly examined, and practical methods of noise control are suggested.
American Industrial Hygiene Association Journal, Feb. 1974, Vol.35, No.2, p.107-111. Illus. 2 ref.

CIS 75-584 Hünting W., Nemecek J., Grandjean E.
Physical workload in drop forging - A case study
Die physische Belastung von Arbeitern an der Gesenkschmiede - Eine Fallstudie [in German]
The authors carried out the following tests on 2 forging hammer operators working on 2 forgings of different weight: recording of heart rate, analysis of work simultaneously with measurement and recording of pulse rate, measurement of radiant heat and noise. The average increase in heart rate associated with drop forging work was 40 beats/min higher than at rest, and was thus at the upper limit of tolerable physical workload. It varied according to the number of forgings, their weight and the radiant heat factor. The noise level reached 120dB and exceeded tolerable limits.
SPM - Sozial- und Präventivmedizin - Social and Preventive Medicine - Médecine sociale et préventive, July-Aug. 1974, Vol.19, No.4, p.275-278. Illus. 4 ref.

CIS 75-372 Nemecek J.
Hearing damage in industry
Hörschäden in der Industrie [in German]
Influence of the intensity, duration and periodicity of noise on temporary hearing threshold shift; deafness due to noise and presbycusis; noise assessment criteria and permissible threshold levels for exposure to intermittent and steady-state noise; enumeration of preventive measures (reduction of noise at source, prevention of its spreading, organisational measures, medical examination, personal protective equipment).
SPM - Sozial- und Präventivmedizin - Social and Preventive Medicine - Médecine sociale et préventive, May-June 1974, Vol.19, No.3, p.185-191. Illus. 10 ref.

CIS 75-371 Rey P.
Occupational deafness
La surdité professionnelle. [in French]
Review of current knowledge on the following aspects: course of occupational deafness; noise-deafness relationship; clinical, anatomical and pathological features of hearing damage due to trauma from explosion, impact noise and steady-state noise. The article refers to French and Swiss legislation on compensation for occupational deafness.
SPM - Sozial- und Präventivmedizin - Social and Preventive Medicine - Médecine sociale et préventive, May-June 1974, Vol.19, No.3, p.177-183. Illus. 17 ref.

CIS 75-369 Schulz G., Haering H.U.
Elimination of impulse noise from diesel locomotives
Beseitigung von Impulslärm bei Diesellokomotiven [in German]
Study of noise emitted by a new type of diesel locomotive: apparatus used for measurement, measurement and analysis of sound pressure level and 3rd octave spectrum when idling and under load. At 80 and 160Hz frequencies, higher noise levels were obtained with a cathode-ray oscillograph than with a sound level meter, pointing to a phenomenon of impulse noise. This noise was found to originate in vibrations explained by exhaust gas dynamics in the exhaust pipe. Design modifications resulted in considerable reduction of noise in the driver's cab and in the vicinity.
Stahl und Eisen, 4 July 1974, Vol.94, No.14, p.618-626. Illus. 16 ref.

CIS 75-368 Martin R.
Noise control
Lärmbekämpfung [in German]
Survey of books, reports, articles, regulations and standards published throughout the world between 1970 and 1972, on the following aspects: noise due to machinery, gear transmissions, fans, motor cars, vehicles on rails, aircraft, etc.; noise abatement, noise measurement.
VDI-Z, June 1974, Vol.116, No.9, p.699-710. 249 ref.

CIS 75-80 Sehrndt G.A.
Noise reduction measures on machine tools
Massnahmen zur Lärmminderung an Werkzeugmaschinen [in German]
Illustrated description of full or part enclosure of presses. Automatic manipulators for forging machines, anti-vibration slide-guides for circular sawblades, and acoustic enclosures for automatic lathes are also discussed.
VDI-Z, Aug. 1974, Vol.116, No.11, p.869-873. Illus. 8 ref.

CIS 75-78 Černjuk V.I.
Combined action of low-frequency vibration and noise
Kombinirovannoe vozdejstvie nizkočastotnoj vibracii rabočih mest i šuma [in Russian]
Experimental study of the combined action of steady-state noise and low-frequency vibration (e.g. of agricultural machines) on young men who were examined before and after exposure and also after recovery periods of 15 and 30min. It was found that the combined action of low-frequncy vibration and noise below the threshold limit gives rise to marked physiological changes. Some of these changes (affecting the stable sagittal vision and the latent period of visual-motor response) persist even after a 30-min recovery period.
Gigiena i sanitarija, June 1974, No.6, p.97-98. 2 ref.

CIS 75-77 Sound damping of premises in the textile industry
Lärmeindämmung in den Räumen der Textilindustrie [in German]
Diagrammatic illustration of sources of machinery noise. Antivibrating mountings on textile machinery. Measures to reduce noise propagation and sound insulation of premises. Information on sound absorption treatment of walls and ceilings.
Textiltechnik, Jan. 1974, Vol.24, No.1, p.59-61. Illus. 2 ref.

CIS 75-74 Alm S., Dahlstedt S.
Noise control in the manufacturing industry - Examples of noise reduction measures with an outline of acoustic principles
Bullerbekämpning inom verkstadsindustrin - Exempel på bullerreducerande åtgärder jämte en kort presentation av bullertekniska principer [in Swedish]
This report describes numerous examples of noise control solutions in foundries, forging shops, plate stores, shipyards, press shops, metal cutting, materials handling, ventilation systems, compressed air equipment and woodworking machinery. A theoretical section contains chapters on: noise control measures in buildings and premises; acoustic design criteria; definitions of acoustic quantities and phenomena. Numerous tables and diagrams and a catalogue of sound insulating materials are appended.
Undersökningsrapport AMT 101/74, Arbetarskyddsstyrelsen, Fack, 100 26 Stockholm 34, Sweden, 1974. 400p. Illus. 6 ref. Price: Swe-cr.40.00.

CIS 75-73 Koss L.L., Alfredson R.J.
Identification of transient sound sources on a punch press.
The sources of transient noise on a 4-t punch press were located through the use of statistical correlation techniques (multiple-input correlation theory). It was found that sound was radiated due to changes in the force time curve resulting from material fracture, material cutting and by the take-up of clearances between shafts and bearings. If the frequency content of the region of change in the force time curve is near resonance frequencies of the structural elements of the press, resonances will be excited and noise will be radiated. Ringing vibrations of structural elements could be prevented by isolating the C-frame from its supporting structure.
Journal of Sound and Vibration, 8 May 1974, Vol.34, No.1, p.11-33. Illus. 14 ref.

CIS 75-70 Ho M.T., Quinot E.
The appearance and aggravation of deafness in a population exposed to noise - Simulation by a stochastic, compartmental epidemiological model
Apparition et aggravation de la surdité dans une population exposée au bruit - Simulation par un modèle épidémiologique stochastique et compartimental. [in French]
The authors applied a method of probability analysis developed for the study of pneumoconiosis in mines to diseases caused by noise, with the chief aim of establishing hygiene standards (average permissible noise level). The basic parameter of the epidemiological model employed is the probability of aggravating hearing loss in a subject exposed to a given level of noise for a specific period of time. The values obtained with this experimental model still require validation in the light of a study employing audiometry and sound-level measurements undertaken within French industry by the French National Research and Safety Institute (INRS), but they have already been found to be numerically consistent with certain data at present available.
Cahiers de notes documentaires - Sécurité et hygiène du travail, 2nd quarter 1974, No.75, Note No.895-75-74, p.201-214. Illus. 1 ref.

CIS 75-69 Plath P.
Differential diagnosis, for the purposes of assigning degree of incapacity, of deafness due to noise as specified in section 26 of the Seventh Occupational Diseases Ordinance (Fed.Rep. of Germany)
Zur Differentialdiagnose und Begutachtung der Lärmschwerhörigkeit als Berufskrankheit nach Ziffer 26 der 7. BKVo [in German]
Loss of hearing, concentrated principally in the 4-6kHz frequency range, aggravated through exposure to noise, is not considered to be sufficient for establishing occupational deafness due to noise. The author reviews the statistical results of audiometric examinations carried out on 1,000 persons and defines the significant additional criteria for a diagnosis of permanent hearing loss due to noise.
Arbeitsmedizin - Sozialmedizin - Präventivmedizin, Apr. 1974, Vol.9, No.4, p.71-75. Illus. 13 ref.

CIS 75-68 Passchier-Vermeer W., Van Leeuwen H.A.
Temporary threshold shift and industrial audiometry
Tijdelijke gehoordrempelverschuivingen en bedrijfsaudiometrie [in Dutch]
Temporary threshold shifts (TTS) should be noted when recording audiograms of noise-exposed workers during working hours. Data are given on the TTS in occupationally-exposed persons (auditory recovery period; relationship between TTS and permanent threshold shift; TTS recovery as a logarithmic function of time; influence of length of service). The objectives of industrial audiometry are set out with respect to groups and individual workers.
Tijdschrift voor sociale geneeskunde, 14 June 1974, Vol.52, No.12, p.440-442. Illus. 9 ref.

CIS 75-65 Hoffmann H.
The future evolution of the occupational disease "noise-induced hearing loss and deafness" - Forecast and consequences
Die zukünftige Entwicklung der Berufskrankheit "Lärmschwerhörigkeit und Lärmtaubheit" (BK 26) - Prognose und Folgerungen [in German]
From data concerning notified and compensated cases of noise-induced disease from 1950 to 1972 in the Federal Republic of Germany and using the pattern of the evolution of silicosis from 1930 to 1970, a statistical prognosis for noise-induced diseases up to 1985 is presented. It is concluded that these will reach about 4,000 cases in 1982, that is, as high as the overall total compensated occupational diseases in 1971. Consequences and measures concerning the insured workers, the size of the noise problem and noise exposure are listed.
Die Berufsgenossenschaft, Mar. 1974, No.3, p.127-136. Illus.

CIS 74-1889 Malyšev Ė.N., Skorodumov G.E.
Concerning the effects of infrasound on the human body
K voprosu o vlijanii infrazvuka na organizm [in Russian]
The higher levels of acoustic pressure found in the sound frequency spectrum of certain machinery (turbines, compressors, fans, diesel engines) are situated within the infrasound frequency band. Their intensity exceeds 100dB and may in some cases reach 135dB. The article describes an experimental chamber where biological research on exposure to infrasound was carried out, demonstrating that low-frequency sound causes the human internal organs to vibrate. These vibrations give rise to discomfort, headache, inappetence, nausea and fatigue. Infrasound control is based on the same principles as noise control and ultrasound control.
Gigiena i sanitarija, Mar. 1974, No.3, p.27-30. Illus. 1 ref.

CIS 74-1888 Harmful effects of noise at the workplace
Gehörschädigender Lärm am Arbeitsplatz [in German]
La nocivité du bruit à l'emplacement de travail. [in French]
The first part of this study reviews Swiss legislation on this subject and deals with the basic physical concepts involved and the principles of measuring noise in industry. This is followed by a part devoted to the assessment of the harmful effects of noise on hearing. The Swiss National Accident Insurance Institute considers that continuous equivalent sound pressure levels of 90dBA and above cause hearing damage. Measures for protection against noise are discussed in a subsequent part (noise control at source, reduction of sound propagation, personal protection).
Cahiers suisses de la sécurité du travail, Sep. 1973-Jan. 1974, No.113. 72p. Illus. Gratis.

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