Noise - 2,325 entries found
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Method of measuring noise from machine tools excluding testing in anechoic chambers [United Kingdom]
This standard specifies the procedure for carrying out noise tests on machine tools. It covers test conditions (general, suitability of rooms, site testing, background noise, mounting conditions); measurement (measuring points, instruments and type of measurement); variation of noise with time and presentation of results. Appendices contain diagrams relating to measuring positions around machines, calculation of levels (octave band mean levels and mean sound levels in dBA), recommended recording of results and machine tool noise test reports.
British Standards Institution, 2 Park Street, London W1A 2BS, United Kingdom, 30 Mar. 1972. 17p. Illus.
Marinjako A.Z., Lipovoj V.V.
Evaluating total noise exposure in the case of intermittent noise
Učet summarnogo vremeni otdel'nyh šumovyh vozdejstvij pri gigieničeskoj ocenke preryvistyh šumov [in Russian]
The effects of exposure to certain types of intermittent noise were studied in an anechoic chamber, and compared with exposure to continuous noise for the same aggregate period of time. It was found in every case that the determining factor in the assessment of intermittent noise was the time distribution of periods of noise and absence of noise, rather than the total exposure to noise.
Gigiena truda i professional'nye zabolevanija, Aug. 1972, Vol.16, No.8, p.15-18. Illus. 2 ref.
Emerson P.D., Overman H.S.
Reduction of noise from rotating textile spindles
Textile spindles are said to be responsible for about 80% of the total noise generated in spinning and twisting operations. Noise levels in textile yarn spinning generally exceed 90dBA; most of this noise is due to vibrations caused by unbalanced loads concentrated outside of bearing supports and is transmitted to machine frames and radiated to the air. Experiments were carried out by adding weight to pindle bolsters; this resulted in substantial vibration reduction, but in no corresponding noise reduction at a distance of 60cm from the spindle.
American Industrial Hygiene Association Journal, Apr. 1972, Vol.33, No.4, p.252-257. Illus.
Specific assessment of airflow noise from fans
Udel'naja ocenka aėrodinamičeskogo šuma ventiljatorov [in Russian]
Suggests a method for the evaluation of airflow noise from centrifugal and axial fans on the basis of the geometrical characteristics of impellers. The results of previous experiments (variations in noise pressure level and acoustic power level depending on rotation speed of centrifugal and axial-flow fans) are shown graphically.
Sudostroenie, Sep. 1972, Vol.62, No.9, p.28-30. Illus. 7 ref.
Woods practical guide to noise control
This introductory textbook on noise control in 7 chapters covers: the fundamentals of noise (how it occurs, its structure, and units and definitions used to describe it); hearing and noise acceptability; measurement of acoustic properties; calculation of noise levels in given situations; calculation of noise in ventilating systems; principles of noise control, noise control in practice. Appendices include: approximate values of absorption coefficients for various internal finishes to walls, floors, etc.; representative values of airborne sound-reduction indices for some common structures; a glossary of acoustical terms; and various conversion tables.
Woods of Colchester Ltd., Tufnell Way, Colchester CO4 5AR, Essex, United Kingdom, 1972. 208p. Illus. 42 ref.
Special features of noise exposure and noise control at the workplace
Besonderheiten der Lärmbelastung und Lärmminderung am Arbeitsplatz [in German]
Following an introduction on the effects of workplace noise and maximum permissible noise levels, the author provides information on the design of soundproofed control cabins designed for short-term or long-term occupation. Additional heat stress and the effect of noise on stereoscopic acuity are also considered. General advice on noise-control measures is also given.
Stahl und Eisen, 9 Nov. 1972, Vol.92, No.23, p.1170-1173. Illus. 21 ref.
Ministre chargé de la protection de la nature et de l'environnement
Order of 11 April 1972, limiting the level of airborne noise produced by motorised compressor sets
Arrêté interministériel relatif à la limitation du niveau sonore des bruits aériens émis par les groupes moto-compresseurs, 11 avril 1972 [in French]
This order, made under the Decree of 18 April 1969 concerning the sound proofing of machines used for building construction (CIS 69-1731), applies to air compressors operating at less than 50m from residential or other premises. The overall level of airborne noise, at a distance of 1m, shall not exceed 85dBA in the case of compressors constructed or impored after 1 October 1972. The experiment must be approved under a specified procedure, and an identity plaque must be affixed to each machine, indicating the noise level measured during approval testing. Sound-proofing devices must be kept in good condition. Transitional provisions concerning compressors in use before 1 October 1972. Schedule: certificate of approval to be issued by the manufacturer or importer.
Journal officiel de la République française, 1-2 May 1972, Vol.104, No.103, p.4534-4535.
Ministre chargé de la protection de la nature et de l'environnement
Order of 11 April 1972 limiting the level of airborne noise produced by the internal combustion engine of earthmoving and similar equipment
Arrêté interministériel relatif à la limitation du niveau sonore des bruits aériens émis par le ou les moteurs à explosion ou à combustion interne de certains engins de chantier, 11 avril 1972 [in French]
This order, made under the Decree of 18 Apr. 1969 concerning the sound proofing of machines used for building construction (CIS 69-1731), stipulates that the level of airborne noise produced by the engines of earthmoving and similar equipment constructed or imported after 2 May 1972 shall not exceed 80dBA at a distance of 7m. Such equipment must be tested and approved in accordance with specified standards. The sound-proofing devices must be kept in good condition. Transitional provisions concerning equipment constructed or imported before 2 May 1972. Schedule: specifications (to be included in articles and conditions of sale) with respect to assessment of airborne noise; model for certificate of approval.
Journal officiel de la République française, 1-2 May 1972, Vol.104, No.103, p.4535-4536.
Kudrjavcev F.S., Lagunov L.F., Solov'ev R.V.
Silencer units for turbocompressors
Kompleks glušitelej šuma dlja turbokompressorov [in Russian]
Description of silencer units for the intake and exhaust openings of a heavy-duty turbocompressor installation in an engineering works. The intake silencer comprises 2 chambers; the first contains vertically-staggered hollow sheet-metal baffles filled with mineral wool; the second contains horizontally-arranged baffles. The exhaust air passes through 2 layers of crushed quarry stone constituting the exhaust silencer. These simple but effective silencers reduce the intake noise level by 25dB at 1000Hz and 40dB at 8000Hz; the exhaust noise level is reduced by 57dB and 67dB, respectively. The article contains diagrams of the intake and exhaust noise spectra and drawings of the silencer units.
Naučnye raboty institutov ohrany truda VCSPS, 1972, No.78, p.67-71. Illus. 4 ref.
Noise control on metal-cutting circular saws
Sniženie šuma diskovyh pil pri rezke metalla [in Russian]
The author studied the sound radiation of large-diameter metal-cutting circular saws, the noise level of which exceeded 100dB. He found that saw-blade vibrations can be attenuated by increasing the diameter of the mounting flanges and inserting vibration-absorbing packings between the flanges and the saw blade. The noise level can be further reduced by designing larger guards and lining them with foamed material.
Naučnye raboty institutov ohrany truda VCSPS, 1972, No.78, p.71-72.
Noise and vibration control in the rubber industry
Combaterea zgomotului şi a vibraţiilor în industria cauciucului [in Romanian]
The author analyses the main noise sources in the rubber industry and proposes several engineering solutions for suppressing noise sources or for preventing the noise produced from exerting harmful effects on the body. With the help of photographs and diagrams, he describes a number of noise-control devices for compressor stations, pumps, starters, burners, pressure reducers, fans, pneumatic tools, etc. A number of the solutions proposed are novel and could be utilised in other branches of industry.
Industria uşoară, Aug. 1972, Vol.19, No.8, p.498-502. Illus. 3 ref.
Kubík Š., Vladár M.
Dynamics of noise-induced temporary hearing threshold shift increase
Dynamika rastu dočasného posunu sluchového prahu v hluku [in Czech]
Study of the relationship between temporary threshold shift (TTS) and noise-exposure duration (2 and 4h) showed that TTS increase was directly proportional to the rise in sound pressure level and not to exposure duration. Audiometric testing after several hours of exposure does not guarantee correct evaluation of degree of hazard. TTS increase dynamics are the critical factor and must be compared with noise conditions at the workplace.
Pracovní lékařství, Dec. 1971, Vol.23, No.10, p.359-361. Illus. 2 ref.
Hluk na pracovištich svářeců [in Czech]
A study of the sources, causes, characteristics, levels and frequency spectra of noise to which welders are exposed. Measurements are illustrated diagrammatically.
Zváranie, Apr. 1971, Vol.20, No.4, p.123-127. Illus. 5 ref.
Direction générale du travail et de l'emploi, sous-direction de l'hygiène et de la sécurité du travail, 2e bureau
Circular T.E. 34/71 of 26 November 1971 concerning the protection of workers from the harmful effects of noise
Circulaire T.E. 34/71 du 26 novembre 1971 concernant la protection des travailleurs contre les effets nuisibles des bruits [in French]
Technical commentary on French Decree No. 69-348 of 12 April 1969. Individual sections are devoted to: noise characteristics; measurement and analysis of noise and its effects on hearing (noise level measurement, noise level contours, audiometry); noise control measures (group and personal protection, medical supervision). Appendices contain: the recommendations of the Technical Noise-Study Committee of the French Ministry of Public Health indicating acceptable levels of industrial noise, noise danger limits, and worker audiometry. The circular was published in "Journal officiel de la République française" of 25 January 1972.
Cahiers de notes documentaires - Sécurité et hygiène du travail, 2nd quarter 1972, No.67, Note No.793-67-72, p.205-215.
Noise reduction in industry
Lärmminderung in der Industrie [in German]
Collection of papers on noise control, covering the following subjects: principles of airborne, machine and plant noise measurement; machine and plant noise reduction (noise types, reduction at source, flow noise, vibration dampers, machine and smelting and refining plant noise control); structural noise control measures; noise level calculation techniques, equivalent continuous noise level and "effective-level technique"; observance of maximum machine and plant noise levels.
Verlag Stahleisen mbH, Postfach 8229, 4 Düsseldorf, Germany(Fed.Rep.), 1971. 98p. Illus. 112 ref.
Alvarez Rico M.
El ruido [in Spanish]
Sections are devoted to: noise characteristics; hearing mechanism; noise physiology; noise measurement; measurement units; units which make allowance for subjective perception; noise analysis and evaluation; effects on the body; and industrial noise control (suppression of machine noise, masking unpleasant noises by pleasant background noise, soundproof cabins, personal protective equipment, reduction of exposure time, shift rotation, work breaks).
Documentación de seguridad No.2, Comisión de seguridad en la industria siderometalúrgica, Avenida José Cueto 40, Avilés, Spain, 1971. 25p. Illus. 20 ref.
Personal ear protection
Following a broad literature survey of the various aspects of hearing protection, the author discusses numerous methods used to evaluate the attenuation characteristics of ear protectors and considers additional features which influence the acceptance of certain types of protectors. The devices covered include earplugs, earmuffs, ear sockets, helmets, etc., to the exclusion of purely experimental devices. Attention has been paid in the report to the need for communication, the use of additional types of protective equipment and the requirements of comfort and wearability.
Report SAM-TR-71-13, School of Aerospace Medicine, Brooks Air Force Base, Texas 78235, USA, Aug. 1971. 143p. Illus. 186 bibl.
Report of Working Group 63, National Academy of Sciences
Non-auditory effects of noise
An evaluation, in summary fashion, of concepts and research data on the effects of noise on non-auditory mental and motor activity and on general health and mental wellbing. Unexpected or fearful noises have been excluded from this survey. The contents are arranged as follows: introduction; physiological effects (non-auditory); effects of arousal responses on health; environmental noise and sleep; other behavioural activities and relation to stress; tolerable noise limits as judged by society; use of animals in studies of non-auditory effects of noise; conclusions and recommendations for further research.
National Research Council Committee on Hearing, Bioacoustics and Biodynamics, Washington, DC, USA, June 1971. 17p. Illus. 25 ref.
Becker R.W., Poza F, Kryter K.D.
A study of sensitivity to noise
An investigation was carried out on 140 subjects during a 6-month period to determine whether there are different degrees of psychological and physiological sensitivity to impulsive and non-impulsive noise in a large group of people, to determine whether and how such sensitivity varied in time, and to relate such sensitivity to other psychological and personality variables. The experimental procedure is described (16 laboratory noises were used), and the physiological (heart rate acceleration, electromyographic reactions) and psychological (acceptability or annoyance) responses were assessed. Significant individual differences were found as regards psychological - but not physiological - sensitivity.
Stanford Research Institute, Menlo Park, CA 94025, USA, June 1971. 65p. 7 ref.
Recommendation 141 concerning control of harmful noise in crew accommodation and working spaces on board ship [ILO]
Recommandation concernant la lutte contre les bruits nocifs dans les locaux de l'équipage et dans postes de travail à bord des navires [BIT] [in French]
ILO Recommendations adopted by the International Labour Conference in 1970. They concern: research into the harmful effect of excessive noise on seafarers and into the development of appropriate preventive measures; training of seafarers; provision of ear plugs and/or ear muffs; noise reduction and control in crew quarters, engine rooms and other machinery places.
ILO Publications, 1211 Genève 22, Switzerland, 1970. 2p.
An attempt to provide the layman with the basic knowledge necessary to understand the causes and effects of noise and its medical, social and legal implications in modern industrial socieity. A glossary of acoustical terms is appended.
Penguin Books Ltd., Harmandsworth, Middlesex, United Kingdom, 1970. 268p. Illus. 10 ref.
Batolska A., Begov A.
Ultrasound and the hearing system
Ultrazvuk i sluh [in Bulgarian]
Low levels of ultrasound accelerate the normal biological processes, and high levels produce protoplasmic cellular lesions due to mechanical and chemical factors (vacuolisation and tissue necrosis). Study of hearing and certain biological indices in 41 subjects exposed to ultra-sound, broken down into groups by age and duration of exposure, showed that the most frequent complaints were tinnitus and reduced auditory acuity. After the day's work, the audiogram curve increased 50dB for high frequencies, remained stationary for medium frequencies and increased only insignificantly for the low frequencies. These changes vary between individuals and in some cases may be absent. No changes in erythrocyte haemoglobin content were found. In more than one-third of the subjects there was a tendency to acid haemolysis. In a number of cases there was a fall in reduced glutathion which is attributed to erythrocyte fragility. No clear correlation was found between biochemical indices and temporary hearing disorders.
Naučni trudove na NIOTPZ - Razdel uši-nos-gărlo i stomatologija, 1970, Vol.18, p.18-22. Illus. 8 ref.
Handbook of noise and vibration control
A reference book including much new material and voering: psycoacoustics; sound fields, sound propagation; noise measurement techniques and instruments; torsional vibration; legal aspects; noise and vibration control; silencers; acoustic absorption materials, insulation, partitions, enclosures, windows, glazing; vibration generators; various types of buildings; different types of machinery (prime movers, road vehicles, electrical machines, pumps, pipework, heating and ventilation systems, pneumatic tools, etc.). Conversion and other useful tables. Buyers' guide (classified index). Trade name index. (For the first edition, see CIS 71-1733).
Trade and Technical Press Ltd., Crown House, Morden, Surrey, United Kingdom, 2nd ed., 1970. 609p. Illus.
Noise in industry
Das Lärmproblem am Arbeitsplatz [in German]
Le bruit dans l'industrie [in French]
This information sheet describes the health hazards associated with industrial noise and proposes measures for noise control and hearing conservation. Contents: effects of noise on hearing, communication and behaviour; occupational deafness; hearing conservation programmes; measurement and engineering control of noise; personal protection devices; audiometry; assessment of disability; damage-risk criteria; legal aspects and compensation for noise-induced hearing loss.
International Occupational Safety and Health Information Centre (CIS), International Labour Office, 1211 Genève 22, Switzerland, Mar. 1968. 56p. Illus. 159 ref.
Maximum acceptable levels for industrial noise
Annehmbare Lärmschwellen in der Industrie [in German]
Limites acceptables des bruits industriels [in French]
This information note provides a comparison of permissible noise levels in France and other countries and presents a maximum acceptable noise level curve for an 8-hour exposure proposed by the Technical Committee for the Study of Noise appointed by the French Ministry of Public Health.
International Occupational Safety and Health Information Centre (CIS), International Labour Office, 1211 Genève 22, Switzerland, Dec. 1961. 4p. Illus. 1 ref.
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