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Hearing protection - 278 entries found

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CIS 80-1390 Zohar D., Cohen A., Azar N.
Promoting increased use of ear protectors in noise through information feedback.
Hearing loss occurring with and without the use of earplugs was measured in workers of a noisy department of a metal fabrication plant. The results were fed back to individual workers to motivate greater use of ear protectors. Over the next 5 months, use of earplugs rose to 85-90%. Only 10% of a control group of workers given a standard lecture on hearing conservation and subjected to disciplinary threats wore earplugs over the same period. The effectiveness of feedback is seen as a 2-stage process involving individual reinforcement and group adoption of new norms for behaviour.
Human Factors, Feb. 1980, Vol.22, No.1, p.69-79. Illus. 21 ref.

CIS 80-1387 Royster L.H.
An evaluation of the effectiveness of two different insert types of ear protection in preventing TTS in an industrial environment.
The V-51R and E-A-R insert protectors were evaluated in an industrial environment with an average level of 95.6dB(A). Workers wearing the V-51R design showed significant daily shifts in hearing levels, and significantly greater shifts than those wearing E-A-R plugs. Subjectively too the E-A-R protectors provided better sound attenuation.
American Industrial Hygiene Association Journal, Mar. 1980, Vol.41, No.3, p.161-169. 45 ref.

CIS 80-972 The danger of evaluating hearing protectors on their attenuation alone.
This booklet illustrates how the attenuation of a hearing protector has little bearing on effective protection unless it is worn for the full duration of noise exposure. Aspects dealt with are: total noise dose; effect of removal of hearing protectors during noise exposure; comparison of earmuffs and earplugs; frequency spectra; dangers of overprotection.
Bilsom AB, 260 50 Billesholm, Sweden, 1980. 15p. Illus. 4 ref.


CIS 81-379 Kracht L., Parthey W., Heidekrüger A.
List of hearing protection regulations
Titelverzeichnis von Vorschriften zum Gebiet Lärmschutz [in German]
Booklet listing some 1,000 standards (as well as laws and directives) on hearing protection. Part 1 classifies these instruments by international organisation (ILO, ISO) and by country (24 countries, mainly European, also Japan and USA). Part 2 (thematic aspects): basic concepts, immission, emission, acoustics, hearing protection equipment and materials, personal protective equipment, audiometry.
Zentralinstitut für Arbeitsschutz, Gerhart-Hauptmann-Strasse 1, 8020 Dresden, German Democratic Republic, 1979. 114p.

CIS 81-62
Federation of Industrial Mutual Accident Insurance Associations (Hauptverband der gewerblichen Berufsgenossenschaften)
Personal hearing protection - Types, technical data, choice
Persönlicher Schallschutz - Typen, Eigenschaften, Auswahl [in German]
Data sheet intended for those reponsible for choosing industrial hearing protection: presentation of various types of insert earplugs, earmuffs and acoustic helmets. Taking account of the OSH specifications of pertinent standards, this data sheet advises on choice of hearing protection on the basis of the noise diminution they afford. Description of 2 methods for selection, according to (1) recommended range of utilisation and (2) octave spectrum at the workplace. Other possibilities of evaluation: manufacturer's specifications, tests carried out by user, selection criteria (form, dimensions and other technical data, personal characteristics, microclimate). Appended: synoptic table of hearing protection models available commercially in the Federal Republic of Germany, indicating scope of use and range of protection afforded, noise level diminution, weight and other data, and supplier's address.
Carl Heymanns Verlag KG, Gereonstrasse 18-32, 5000 Köln 1, Federal Republic of Germany, Oct. 1979. 20p. Illus. 16 ref. Price: DM.3.00.

CIS 80-1874 Axelsson A., Axelsson K., Jonsson A.
Use of hearing protection in a Swedish engineering plant, 1977
Hörselskyddsanvändning i en svensk verkstadsindustri 1977 [in Swedish]
Two groups of workers were selected for a survey in a large Swedish vehicle manufacturing plant, one with severe hearing damage, the other with normal hearing. The use of hearing protection by these 2 groups was compared. Age and exposure were more or less equivalent. Use of hearing protection was more frequent among those who had normal hearing. It appears that some people can work in a noisy environment for many years without hearing protection and still retain normal hearing. On the other hand, certain individuals who report diligent use of hearing protection present unmistakable hearing damage. Hearing protection of the insert plug type was most popular. Reasons for failure to use hearing protection were analysed. Continuous worker information on hearing protection is essential in industries with noise problems.
Läkartidningen, Mar. 1979, Vol.76, No.12, p.1079-1082. Illus. 4 ref.

CIS 80-966 Ettema J.H., Passchier-Vermeer W., Dijkers J.H.G.M., Scheffer J.G.J.M., Lindeman H.E., Bruggink H.J., Smoorenburg G.F., Mimpen A.M., Van Leeuwen H.A., Verbeek J., Van Dijk F., Knipschild P., Fertigova H., Van Steenbrugge B.
Man, noise and work
Mens, lawaai en arbeid [in Dutch]
Research by the Dutch working group on noise/hearing loss relations is reported: audiometry as a function of the industrial health unit; comparison between threshold and screening audiometry; individual noise dosimeter; disturbance due to noise; hearing loss due to impulse noise; hearing protection; extra-auditory effects of noise; noise control (noise measurement, acoustical classification and soundproofing of rooms and machinery).
Tijdschrift voor sociale geneeskunde, 28 Dec. 1979, Vol.57, No.25, Suppl. 1, 43p. Illus. 99 ref.

CIS 80-698
BOHS Technology Committee, Working Party on Hearing Protectors.
Guide for the design of hearing protectors for general industrial use.
Guidance is given on physical requirements for comfortable, durable, and generally acceptable personal hearing protectors: terminology; attenuation; materials; cleaning; durability; physical requirements; colour; comfort; information, instruction and marking. Appendix: apparatus for measuring spring-band forces and pressure of earmuffs. These aspects are not covered by British Standard 5108 (1974) on measurement of attenuation of hearing protectors.
Annals of Occupational Hygiene, 1979, Vol.22, No.3, p.203-211. 11 ref.

CIS 80-393 Van Orsouw J.G., Meertens D.J.
Noise in building and civil engineering - What you must know - What you can do
Lawaai in de bouw - Wat moet je weten - Wat kun je doen [in Dutch]
This booklet intended for construction site workers emphasises the high incidence of hearing loss among occupational diseases. Contents: basic principles of acoustics; effects of over-exposure to noise on man; noise sources in building and civil engineering work; noise reduction measures (examples of silencers, sound-absorbing panels and other soundproofing measures on vehicles, machines and earthmoving equipment); personal protective equipment (earplugs, earmuffs); role and responsibility of management in noise control; environmental protection. Annex: table listing typical machinery and equipment, with corresponding engineering and organisational noise control methods.
Bureau Bouw Veilig, Postbus 637, 1000EE Amsterdam, Netherlands, no date, 48p. Illus. Gratis.

CIS 80-388 Lessing G., Sauer U.
Personal hearing protection and audibility of acoustic signals
Individueller Gehörschutz und Hörbarkeit akustischer Signale [in German]
Field studies on the disturbance value of tractor noise indicated that subjects with normal hearing experience no diminution of audibility of acoustic signals when wearing hearing protection. Some even noted an improvement (confirming other reports). In persons with impaired hearing there was a loss of audibility of the signals. The threshold for deterioration was approx. 15% hearing loss (Fowler-Sabine determination). Practical conclusions are drawn.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, Feb. 1979, Vol.25, No.2, p.113-117. Illus. 11 ref.

CIS 80-386 Thunder T.D., Lankford J.E.
Relative ear protector performance in high vs low sound levels.
The attenuation of a commercial earplug was determined in 5 subjects with normal hearing and 5 with impaired hearing. The impaired-hearing group yielded significantly less attenuation than normal subjects. Since the measuring sound intensity level was high for the subjects with impaired hearing and low for the normal subjects, a threshold procedure using normal subjects as presented in American standard ANSI S3.19-1974 may overestimate the actual attenuation of ear protectors in most noisy environments. Reasons for the differences found are discussed.
American Industrial Hygiene Association Journal, Dec. 1979, Vol.40, No.12, p.1023-1028. 13 ref.

CIS 80-71 Hearing protection at hot workplaces - Effect of sweat-absorbing layers on sound attenuation by earmuffs
Gehörschutz an Hitzearbeitsplätzen - Zum Einfluss schweissabsorbierender Zwischenlagen auf die Schalldämmung von Kapselgehörschützern [in German]
Studies with earmuffs with a foam plastic or a liquid-filled cushion and sweat-absorbing elements are described. The sweat-absorbing elements reduce the sound attenuation capacity when dry and increase it after absorption of sweat. For hot work, preference is given to earplugs, which do not impede skin cooling. If earmuffs must be worn, the use of models incorporating a plastic foam cushion and sweat-absorbing elements is recommended.
Die Berufsgenossenschaft, July 1979, No.7, p.388-389. Illus. 3 ref.

CIS 79-1901 Trynkowska D., Michalski R.
Principles for the classification and choice of hearing protectors
Zasady klasyfikacji i doboru ochronników słuchu [in Polish]
Results of tests carried out in Poland by the Central Institute for Worker Protection (CIOP) on 22 types of earmuffs, 1 acoustic helmet and 5 types of earplugs. The tests consisted in determining, by the "hearing threshold shift" method, the acoustic efficacy of hearing protectors for 5 standardised noise spectra obtained from mean spectra established for each classified category of noise produced in Polish industrial plants. Analysis of attenuation curves in relation to the spectral distribution index enabled certain laws to be established which were then used as a basis to devise certain simplified methods for the choice and classification of hearing protectors. The selection method reduces workplace noise measurement requirements; only weighted levels LA, in dB(A), and LC, in dB(C) need be measured. The system of classification, based on the protection afforded according to the noise spectrum, comprises 4 categories: A and B for protectors which attenuate all noise, and B and C for those which attenuate only noise with preponderant medium and high frequencies.
Prace Centralnego instytutu ochrony pracy, 1979, Vol.29, No.101, p.177-189. Illus. 15 ref.

CIS 79-1891 Durkin J.
Effect of electronic hearing protectors on speech intelligibility.
Studies are described showing the speech intelligibility obtained by persons while wearing conventional or electronic hearing protectors under various conditions (various speech and noise levels and spectra, with and without conventional hearing protectors, different hearing sensitivities). A computer model was generated to simulate an individual undergoing speech intelligibility tests. For speakers talking at normal voice levels at noise levels of 65dB or less, it was found that conventional hearing protectors significantly reduced speech intelligibility. Under the same conditions, electronic protectors provided scores equal to those for the unprotected individuals while providing protection from high noise levels. The conclusion is drawn that electronic hearing protection is valuable in areas where high noise level is intermittent.
Report of Investigations 8358, Bureau of Mines, 4800 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA, 1979. 19p. Illus. 11 ref.

CIS 79-1300 Schmuckli F.
Personal hearing protection
Der persönliche Gehörschutz [in German]
La protección individual del oído [in Spanish]
La protezione individuale dell'udito [in Italian]
La protection individuelle de l'ouïe. [in French]
The introduction to this information sheet contains remarks on noise evaluation and on Swiss law concerning the prevention of hearing damage due to workplace noise. Most of the booklet is devoted to a description of various types of personal hearing protection to be worn (technical data, conditions for use), a study of the effects of wearing hearing protection on speech communication, and recommendations concerning the introduction of hearing protection (personal information, period of adaptation before becoming accustomed to wearing protection). Individual objections to wearing personal hearing protection are analysed in the last chapter. Spanish translation published in "Notas y documentos sobre prevención de riesgos profesionales", 148, 4° trimestre 1984, p.11-22.
CSST n°130, Cahiers suisses de la sécurité du travail, Schweizerische Unfallversicherungsanstalt, 6002 Luzern, Switzerland, 1979. 28p. Illus. 24 ref.

CIS 79-1290 Godenhielm B., Perkiö K., Starck J.
Effect of helmet underhats on the attenuation of earmuffs
Kypärän alushupun vaikutus kuulonsuojainten toimintaan [in Finnish]
3 types of earmuffs and cloth and fur underhats were studied by using 13-15 chain saw operators. The difference in attenuation with and without the underhat was measured as the change in the hearing threshold of the subject with Békésy audiometry. An artificial ear (IEC 318 standard) was used for measuring the 1/3 octave band noise at -10° to -20°C. The attenuation of the earmuffs was determined at 20° and -15°C by a miniature microphone attached to the ear tip. The cloth underhat decreased the attenuation by 5dB and the fur hat decreased it to almost zero at frequencies below 1.5kHz. At higher frequencies there was some attenuation with the fur hat and it increased about 15dB/octave. When the earmuffs were against the skin under the hat, the attenuation increased about 24dB compared to the attenuation with earmuffs and without the hat. In the cold environment the attenuation increased at low frequencies and decreased at high frequencies. English summary.
Työterveyslaitoksen tutkimuksia 148, Institute of Occupational Health (Työterveyslaitos), Helsinki, Finland, 1979. 39p. Illus. 14 ref. Price: Fmk.20.00.

CIS 79-1006 Method for determining a suitable band of noise levels for the choice of personal hearing protection for use in noisy areas
Methode zur Bestimmung eines geeigneten Pegelbereiches zur Auswahl von Gehörschützern für Lärmbereiche [in German]
This report presents a practical method for selecting personal hearing protection, which enables its efficiency to be evaluated in different noise environments. The protection is classified according to 2 scales of noise levels (for medium and high frequencies, and for low frequencies) for which its use is recommended. These values are indicated by the manufacturer or by a test laboratory, rendering it unnecessary for the user to make calculations and measurements. The noise spectra used in testing and the methods for calculating the limit level for use of any particular model are described. Appended: scale of recommended noise levels for 51 earmuffs and 15 earplugs.
IFL Report No.1-79, Institut für Lärmbekämpfung des Hauptverbandes der gewerblichen Berufsgenossenschaften, Postfach 2430, 6500 Mainz 1, Germany (Fed.Rep.), no date. 100p. Illus. 12 ref.

CIS 79-996 Toriyama M.
A liquid-containing ear protector.
A new type of ear plug comprising a thin silicone cuff filled with polyethylene glycol and fitted with a valve was tested. The sound energy level was reduced by about 20, 24, 30, 35 and 39dB at 500, 1,000, 2,000, 4,000, and 8,000Hz, respectively. The ear protective effect was equal to that of ear-mould type protectors and considerably better than that of conventional ear protectors. The ear plug adapts well to any type of ear and fits snugly against the wall of the external auditory canal.
Journal of the Japan Accident Medical Association, Jan. 1979, Vol.27, No.1, p.63-70. Illus. 26 ref.

CIS 79-992 Martin A.M.
Dependence of acoustic attenuation of hearing protectors on incident sound level.
Four types of earplug and 4 types of earmuff were tested with cadaver ears fitted with a microphone, using pure-tone and 1/3-octave band steady state stimuli with sound pressure levels of 75-125dB and impulse noise of up to 135-175dB. All 8 hearing protectors had constant attenuation characteristics for the steady state sound levels, as did the 6 conventional protectors for the impulse stimuli. The 2 non-linear amplitude-sensitive protectors investigated (intended for gunfire noise) provided attenuation which increased with incident sound levels for impulse noises. The attenuation characteristics of the 6 conventional models were equal for incident sound levels at about 40 and 75dB, and constant at 75-175dB. Thus the results of threshold-shift procedures using sound levels of up to 40dB may be applied to occupations where hazardous noise is present.
British Journal of Industrial Medicine, Feb. 1979, Vol.36, No.1, p.1-14. Illus. 17 ref.


CIS 92-1076 Health (Hearing Conservation) Regulations 1978 [Australia - Victoria]
Consolidated version of these regulations, which were made in 1978 and which came into operation on 1 Jan. 1979, as amended to 1979. Contents: workers covered by the regulations (workers in mines and quarries are excluded); obligation of employer to reduce noise levels when the Daily Noise Dose exceeds 1.0 or an employee is exposed to noise levels >115dB(A) slow; warning signs; remedial steps; employee obligations; exemptions; audiometric tests; penalties. In the schedules: calculation of Daily Noise Dose.
In: Australian Industrial Safety, Health and Welfare, CCH Australia Ltd., CNR Talavera & Khartoum Roads, Box 230, North Ryde, NSW 2113, Australia, Vol.2, 4p. (pages numbered 62,765 - 62,768). Illus.

CIS 82-809 Fröhlich G.
The effects of hearing protection equipment and hearing loss on the comprehension of speech communication over aircraft noise
Der Einfluss von Gehörschutzgeräten und Hörverlusten auf die Sprachverständlichkeit im Flugzeuglärm [in German]
Following complaints from airport technical workers claiming that hearing protectors impeded speech comprehension, phrase comprehension tests were carried out on persons with normal hearing and persons with auditory deficit. The results of these tests, carried out against a background of aircraft noise (86dB(A)), showed comprehension improvement in those with normal hearing and comprehension reduction in those with hearing loss, when wearing hearing protectors.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Prophylaxe, Mar. 1978, Vol.28, No.3, p.78-81. Illus. 4 ref.

CIS 81-70 Measurement of noise reduction achieved by personal hearing protection (supraliminary subjective method)
Mesure de l'affaiblissement sonore apporté par les protecteurs individuels contre le bruit (méthode subjective supraliminaire). [in French]
The method described in this standard, which aims to give values for noise reduction achieved with hearing protectors, as near as possible to reality in workplace conditions, makes use of a diffuse sound field, complex test sounds and a test environment with a high sound pressure level (100dB in each frequency band). Specification of test site. Choice of test subjects. Test method. Presentation of results.
Association française de normalisation, Tour Europe, 92080 Paris-la-Défense Cedex 7, France, Sep. 1978. 10p. Illus.

CIS 80-64 Waring A.E.
Hearing protection - A review.
This review is for safety officers; legal and compensation aspects; hearing sensitivity and audiometry; noise levels where protection is required; hearing protectors (plugs, ear muffs, amplitude-sensitive ear defender) and choice of protectors. Comparable attenuation characteristics of different hearing protectors (cotton wool, glass fibre down, muff protectors, vinyl rubber plugs) and protection afforded as a function of time worn are shown graphically.
Safety Surveyor, Mar. 1978, Vol.5, No.6, p.5-14. Illus. 11 ref.

CIS 79-1584
ZH 1/565.3, Lärmschutzinformationsblatt LSI 01-830, Federation of Industrial Mutual Accident Insurance Associations (Hauptverband der gewerblichen Berufsgenossenschaften), Bonn, Mar. 1978.
Personal hearing protection - Types, characteristics, selection
Persönlicher Schallschutz - Typen, Eigenschaften, Auswahl [in German]
This data sheet is addressed to those responsible for selection of hearing protectors in industry. It gives a short description of the types of earplugs, earmuffs and acoustic helmets with advice on the choice of appropriate protectors. Two methods are presented for evaluation of the protective effect: based on the sound attenuation capacity for variable noise, and on the octave spectrum of the noise for an invariable spectral distribution. The information and instructions to be provided by the manufacturer are listed. Selection criteria for earplugs (form, size, hygiene, temperature) and earmuffs (sound attenuation, design, sealing element, sealing force, effects of temperature and humidity) are set out. A list of available protectors with indication of the sound attenuation they afford is appended.
Carl Heymanns Verlag KG, Gereonstrasse 18-32, 5000 Köln 1, Germany (Fed.Rep.). 24p. Illus.

CIS 79-991
GOST 12.4.051-78, State Standards Committee (Gosudarstvennyj komitet po standartam), Moskva, 8 June 1978.
Personal hearing protection - General technical conditions
Sredstva individual'noj zaščity organa sluha - Obščie tehničeskie uslovija [in Russian]
This standard, effective 1 Jan. 1979, applies to earmuffs, earplugs and acoustic helmets. Contents: classification; technical requirements for equipment of this type (mass, adherence strength, approval of materials used in manufacture (which should not harm the skin), possibility of adjustment to head measurements, etc.); standardised patterns and models; rules for taking delivery, periodic checks and compliance testing; test methods (at least 5 normal subjects for each type of protector; adjustment and fitting of personal hearing protection for a noise level of 70dB(A); pure tone binaural audiometry at 7 frequencies from 125 to 8,000Hz; standard data for soundproof room and audiometry unit, etc.); marking and packaging; rules for guidance in the selection of personal hearing protection; manufacturer's guarantee.
Izdatel'stvo standartov, Novopresnenskij per. 3, Moskva D-557, USSR, 1978. 6p. Price: Rbl.0.03.

CIS 79-987 Specialist conference on noise
Fachtagung Lärm [in German]
The greater part of this issue is devoted to papers submitted at the conference organised by the Federation of German Coal Mines (Gesamtverband des deutschen Steinkohlenbergbaus) and held at Essen on 7 Nov. 1978. Introductory considerations on trends in noise-induced occupational hearing loss in coal mines are followed by papers on: noise source and noise measurement; West German regulations concerning noise (extracts from draft coal mining regulations); experience acquired in the use of personal hearing protection; principles of noise control; noise control in driving galleries; noise control in coal getting and transport. The draft coal mining regulations reduce the indicative TLV for noise from 90 to 85dB(A); this increases the percentage of mineworkers at risk from 43% to 78% in underground mines, and from 14% to 29% in surface mines. The impossibility of finding engineering solutions for noise reduction at short notice necessitates a considerable extension in the use of personal hearing protection.
Glückauf, 21 Dec. 1978, Vol.114, No.24, p.1075-1094. Illus.

CIS 79-408 Hearing protection.
From the contents of this data sheet: introduction (anatomy and physiology in the ear); definitions; health hazards of noise - hearing damage; acoustic trauma, noise-induced hearing loss (conductive, sensorineural (temporary and permanent threshold shift); psychological effects (e.g. on work performance); stress, heart disease, ulcers; interference with speech communication (accident hazard); Canada Department of Labour recommended noise exposure limits at worksite (table); ear protection against mechancial trauma; noise monitoring (sound level meter, frequency analysers, dosimeters); noise control methods (reduction at source by vibration damping, enclosure, lagging, mufflers, absorbing materials; modification of transmission path (absorbers, panels, barriers)); personal protective equipment (synoptic table showing relative advantages and disadvantages of insert-type and muff-type protectors); pre-placement and periodic hearing examinations; first aid in case of bleeding from the ear, foreign body in the ear, etc.; 2-page summary for posting up.
Data sheet H-1, Canada Safety Council, 1765 St. Laurent Boulevard, Ottawa, Ontario K1G 3V4, Canada, 1978. 24p. Illus. 25 ref. Price: Can-$1.50.

CIS 79-183 Damongeot A., Lafaye R., Krawsky G., Liévin D., Englert M.
Efficacy and comfort of personal hearing protectors
Efficacité et confort des protecteurs individuels contre le bruit. [in French]
Report on tests by the French National Research and Safety Institute (INRS) on 102 hearing protectors (earmuffs and earplugs, including 60 tested in 1972 and 40 newly available models. The increased efficacy of earmuffs and earplugs between 1972 and 1976 is shown and noise attenuation curves, overall attenuation, comfort, mechanical characteristics are given for the new models (22 earmuffs and 18 earplugs). Details of comfort and overall attenuation characteristics are also given for 62 other hearing protectors.
Travail et sécurité, May-June 1978, No.5-6, p.361-381. Illus.

CIS 78-1898 Kuhn H.D.
Selection of individual hearing protectors in practice
Die Auswahl von persönlichen Schallschutzmitteln in der Praxis [in German]
A simplified method of selecting ear protectors is presented. It is based on the rating noise level at the workplace, the results of preventive hearing examinations, and the sound attenuation power (as a function of frequency) of the protectors. The method takes into account various elements (differentiation between normal and high-risk individuals with regard to hearing loss, threshold values of 90 and 86dB(A), rating sound level and frequency range of noise under study), and permits the sound attenuation capacity required of the protector to be determined. The wide scatter of attenuation values for a given type of protector is stressed. There is still no appropriate protection for persons at high hearing loss risk exposed to extreme noise conditions.
Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Prophylaxe, Mar. 1978, Vol.28, No.3, p.81-85. 9 ref.

CIS 78-1886 Whittle L.S., Sutton G.J., Robinson D.W.
The objective measurement of the attenuation of hearing protectors of the circumaural type.
The attenuation of 5 earmuffs using dummy heads of 3 different designs was measured. Results showed variability on repeated attachment of the earmuffs, and an effect of geometrical factors in the design of the dummy heads. Compared with the results of subjective tests the attenuation measured on the dummy heads was consistently the greater, but there was a good correlation between the 2 methods up to 2kHz. Conclusion: results in good agreement with subjective values may become predictable from objective measurements in simple test conditions.
NPL Acoustics Report Ac 87, National Physical Laboratory, Teddington, Middlesex TW11 OLW, United Kingdom, July 1978. 28p. Illus. 12 ref.


CIS 78-1288 Endruweit G., Hach K.
Does wearing earmuffs in noisy workplaces give rise to additional communication difficulties?
Stören Gehörschutzkapseln in Lärmbereichen die Kommunikation noch zusätzlich? [in German]
Description of laboratory tests to ascertain whether complaints concerning interference with speech intelligibility due to wearing earmuffs were justified. The tests consisted in recording the reaction to verbal instructions given to 24 persons exposed to a noise level of 90dB(A) with and without earmuff protection. The results showed that there were more errors in understanding when earmuffs were not worn than when they were. Conclusions: hearing is better (although different) with hearing protection, but a period of adaptation is required.
Sicherheitsingenieur, Sep. 1977, Vol.8, No.9, p.22-25. Illus.

CIS 78-1097 Derevjanko E.A., Lisičkina Z.S., Perrote A.A., Huhlaev V.K.
Efficacy of earmuffs connected to radio broadcasts for noise protection
Ėffektivnost' primenenija radioficirovannyh naušnikov dlja zaščity ot šuma [in Russian]
Results of observations in 47 workers at a food preserving plant over 5 days, involving almost 2,000 physiological measurements. Standardised earmuffs were equipped with earphones transmitting music without impairing their hearing protection properties. Compared with the fatigue measured during work without earmuffs and earmuffs without earphones, the best results were obtained when workers were able to regulate the duration and volume of music at will.
Gigiena truda i professional'nye zabolevanija, Sep. 1977, No.9, p.44-46. 4 ref.

CIS 78-975 Thiemecke H.
Hearing protection campaign
Eine Lärmschutzaktion [in German]
Based on hearing damage risk analysis in a large iron and steel production plant employing 8,000 workers (percentage of hearing damage; personal, technical and administrative aspects of levels of protection against noise) a vigorous hearing protection campaign was organised, with emphasis on information and motivation to promote the use of personal hearing protection. Various stages of the campaign are described: supply of hearing protection; warning notices indicating noise hazard areas; information and motivation programmes for managerial and supervisory staff; propaganda; noise control; follow-up of campaign results and surveillance of exposed personnel; cost of, and future trends in hearing protection programmes.
Sicher ist Sicher, Apr. 1977, Vol.28, No.4, p.166-170; May 1977, Vol.28, No.5, p.222-226. Illus. 23 ref.

CIS 78-697 Acton W.I.
Problems associated with the use of hearing protection.
Paper read at the British Occupational Hygiene Society's annual conference (York, 28-31 March 1977). Areas in which commercially available hearing protectors are still deficient are: durability, size, head band force and pressure of ear muffs, comfort and inherent safety, and ease of speech communication. Sections deal with attenuation, materials, hygiene and cleaning, colour, and the unsatisfactory aspects referred to above.
Annals of Occupational Hygiene, Dec. 1977, Vol.20, No.4, p.387-395. 19 ref.

CIS 78-694 Whittle L.S., Robinson D.W.
On the measurement of real-ear attenuation of hearing protectors by standardised test methods.
After a review of the development of standards in the USA, United Kingdom and internationally, and a summary of the main provisions of British standard BS 5108, this report describes tests performed according to BS 5108 using 5 types of earmuffs and 1 type of earplugs. The results illustrate the repeatability and typical intersubject variances to be expected. Comparison with results at another laboratory, and with the U.S. procedure are reported.
NPL Acoustics Report Ac 79, National Physical Laboratory, Teddington, Middlesex, United Kingdom, Feb. 1977. 29p. 27 ref.

CIS 78-684 Martin A.M.
The acoustic attenuation characteristics of 26 hearing protectors evaluated following the British standard procedure.
Evaluation of 26 commercially available earplugs and earmuffs at an experimental facility incorporating an anechoic cheamber, according to the British standard procedure (BS 5108:1974), is presented. The results obtained were compared with those measured by U.S. standard ASA Z24.22-1957 for 9 protectors. There was no significant difference between them, but the standard deviations for frequencies above 500Hz were significantly lower with the British procedure.
Annals of Occupational Hygiene, Dec. 1977, Vol.20, No.3, p.229-246. Illus. 9 ref.

CIS 78-95 Brinkmann K.
Calculation of the sound attenuation efficiency of hearing protectors
Zur Berechnung der Schallpegelminderung beim Tragen eines Gehörschützers [in German]
Study of methods proposed to assess the efficacy of hearing protectors against a given noise: precise calculation on the basis of the octave spectrum; approximate method from 3 typical noise spectra; American method based on a single noise spectrum (average of 6 noises). The equivalence of 3 methods was tested with 45 industrial noise spectra and 25 hearing protectors. Statistical differences are shown. The approximate methods tend to over- or underestimate considerably the attenuation produced by hearing protectors, so that their information value is not equivalent to that of precise calculation. Application of a safety coefficient could compensate the lesser reliability of the approximate method.
Kampf dem Lärm, Feb. 1977, Vol.24, No.1, p.17-21. Illus. 9 ref.

CIS 77-670
Colour film strip (95 frames: 18x24) or set of 95 colour slides (24x36) with commentary (magnetic tape: 9.5cm/s, or cassette: 4.75cm/s), 18min, 1977.
Noise - Information about ear protection devices.
Bruit - Informations sur la nécessité de la protection de l'ouïe. [in French]
This film strip (or slide) cartoon-documentary with magnetic tape or cassette commentary illustrates the following aspects of noise-induced hearing loss in industry: human organs of hearing, auditory range, effects of noise, noise analysis, use of various methods of hearing protection for different types of noise encountered in industry.
Becker Audio-Visuals, Albisstrasse 107, 8038 Zürich, Switzerland. Price: SF.585.00.


CIS 77-1883 Christ E.
Individual hearing protection and accident hazard
Persönlicher Schallschutz und Unfallgefährdung [in German]
An argument against the wearing of hearing protectors is that changes in the noise quality of machines can contribute to assessment of the smooth running of production processes and to the prevention of accidents. The example of acoustic information indicating malfunction during drop forging shows that the choice of appropriate hearing protection can help the individual adaptation necessitated by changes in the sound characteristics: drop forge noise, sound levels and spectra of the hammer impact, influence of hearing protectors on the noise perceived. Criteria for the choice of hearing protectors which do not impair supervision and evaluation of machine noise are presented.
Die Berufsgenossenschaft, Dec. 1976, No.12, p.474-480. Illus. 8 ref.

CIS 77-1882 Levin G.
Perception of acoustic signals when wearing hearing protectors
Wahrnehmbarkeit akustischer Signale beim Tragen von Gehörschutz [in German]
The main arguments against the use of hearing protectors are disturbance of communication and the inability to hear acoustic signals. It is shown by reference to specific octave spectra that acoustic signals can also be masked by other noise sources. Tests in which the hearing threshold for signals in a noisy industrial environment (mine tools and machinery) or during the use of hearing protectors was determined are reported. At the usual frequencies, noise signals are heard as well or better by workers wearing hearing protectors.
Die Berufsgenossenschaft, Dec. 1976, No.12, p.471-474. Illus.

CIS 77-1692 Use of ear protectors or respirators by workers wearing glasses
Användning av hörselskydd eller andningsskydd tillsammans med glasögon [in Swedish]
These directives (entry into force: 1 July 1977) draw attention to the hazards to which workers who have to wear prescription glasses are exposed when engaged in processes where the wearing of earmuffs or respirators is required, since the stem of the glasses may prevent the earmuffs or respirator from fitting tightly to the head. These workers should wear only earmuffs approved for persons wearing glasses, or glasses with very flat stems. In the case of full-face masks the employer is required to provide the worker with the prescription lenses for his corrected vision mounted in the respirator, or glasses held in place by a head band.
Meddelanden 1976:37, National Board of Occupational Safety and Health (Arbetarskyddsstyrelsen), Fack, 10026 Stockholm 34, Sweden, 9 Dec. 1976. 2p. Gratis.

CIS 77-983 Waugh R.
Calculated in-ear A-weighted sound levels resulting from two methods of hearing protector selection.
The noise levels reaching the ears was calculated by computer for hearing protectors fitted by either the octave-band or the sound level conversion (SLC) method. While selection on the basis of the SLC rating results in a slightly more variable distribution, the method provides an acceptable basis for selecting hearing protectors in any industrial noise spectrum not dominated by intense pure tone or narrow-band energy components.
Annals of Occupational Hygiene, Dec. 1976, Vol.19, No.3-4, p.193-202. 10 ref.

CIS 77-674 Lotito F.
Methods of measuring and rating hearing protector performance.
Methods of measuring and rating the performance characteristics of ear protectors are reviewed against the background of the U.S. standards. Obstacles to acceptance of the octave-band methods are pointed out. The advantages of a single number rating factor are enumerated, and the method of applying this factor explained.
American Industrial Hygiene Association Journal, Oct. 1976, Vol.37, No.10, p.590-595. Illus. 16 ref.

CIS 77-383 Brinkmann K., Brocksch K.H.
Measurement of noise attenuating properties of hearing protectors at high sound pressure levels, and at hearing threshold level
Messung der Schalldämmung von Gehörschützern bei hohen Schalldruckpegeln und an der Hörschwelle [in German]
Description of an experiment comparing the method of hearing thresholds, used in the Fed.Rep. of Germany, and test methods at high sound pressure levels, used in other countries, to measure the attenuation properties of personal hearing protectors. Description of methods used and results of measurements with ear plugs. Conclusion: the hearing threshold method gives reliable and reproducible results, which are not essentially different from those obtained with measurement at high sound pressure levels.
Kampf dem Lärm, June 1976, Vol.23, No.3, p.69-73. 10 ref.

CIS 77-90 Russell M.F., May S.P.
Objective test for earmuffs.
An objective test method was developed by the British firm of Lucas in order to assess how well different types of earmuff attenuate all audible noise under typical factory conditions and are able to accommodate variations in human heads which may affect their acoustic properties. Use was made of a commercial artificial ear embedded in a wooden head which can be adjusted in shape, hair length and contour in the area around the ear. The measurements of earmuff attenuation for 20 different configurations of the adjustable head compare satisfactorily with similar measurements made with 20 human heads and the same earmuffs.
Journal of Sound and Vibration, 22 Feb. 1976, Vol.44, No.4, p.545-562. Illus. 2 ref.

CIS 77-86 Padilla M.
Ear plug performance in industrial field conditions.
With the aid of a relatively simple experimental apparatus, the author tested the real-ear attenuation afforded at 500Hz by both standard-type and custom-made, moulded earplugs. It was found that earplugs in general did not afford adequate protection against excessive noise, although moulded-type earplugs were superior if properly fitted. For these reasons, earplugs should be tested individually after fitting and periodically thereafter.
Sound and Vibration, May 1976, Vol.10, No.5, p.33-36. Illus.

CIS 77-81 Martin A.M.
Industrial hearing conservation - 1: Personal hearing protection - 2: Audiometry.
The author reviews the non-engineering methods of noise control. The first part of his paper discusses the main requirements of a sound hearing protection programme and its ingredients (types, performance, selection and limitations of hearing protectors, etc.), while the second part considers the technical and practical requirements of a monitoring audiometry programme (types and calibration of audiometers, audiometric methodology, financial considerations, etc.).
Noise Control - Vibration and Insulation, Feb. 1976, Vol.7, No.2, p.42-50 and Mar. 1976, Vol.7, No.3, p.71-77. Illus. 24 ref.

CIS 76-1868 Personal hearing protection
Persönlicher Schallschutz [in German]
This data sheet gives general information on various types of personal hearing protection (earplugs, earmuffs, helmets) available in Germany (Fed.Rep.) with the distinctive features of each model (supplier, noise attenuation and price), set out in tabular form. Noise attenuation in relation to frequency range is shown graphically. The text of the directive of the Association of German Engineers VDI 2560 respecting personal hearing protection (types of hearing protectors, required characteristics, selection and use of protectors) is appended.
Lärmschutz-Informationsblatt LSI 01-830, Federation of Industrial Mutual Accident Insurance Associations (Hauptverband der gewerblichen Berufsgenossenschaften), Langwartweg 103, 5300 Bonn 1, Germany (Fed.Rep.), 1976. 10 + 9p. Illus. 14 ref.

CIS 76-1590 Press H.
Measurement of sound levels and hearing protection in plasma-arc cutting
Messungen des Schallpegels und Massnahmen zum Gehörschutz beim Plasmaschneiden [in German]
Results of sound level measurements in different conditions of use of the plasma-arc torch showed that the permissible sound pressure level (90dBA) is always greatly exceeded. Study of the influence of the gas volume and composition, electric power, cutting speed and distance between the torch and the workpiece. Some attenuation of noise is obtained by reducing the electric power and the gas volume. A water jacket surrounding the plasma jet gives more interesting results. Wearing of ear protection is essential. French translation may be obtained from INRS, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France.
Schweissen und Schneiden, 1976, Vol.28, No.2, p.65-68. Illus. 6 ref.

CIS 76-1585 Waugh R.
Investigation of sound level conversion as a means of rating ear protector performance.
Sound level conversion (SLC), which results in a single-number value describing the noise reduction (the difference between the source C-level and the received A-level) afforded by ear protectors, was performed for 30 ear protectors in 615 industrial noise spectra. The SLC value is useful for situations in which the noise hazard is characterised only by C- and A-weighted sound levels. A simple procedure for calculating the SLC value, accurate to within ±1dB, is proposed. Protection rates of 50-97@1p can be achieved.
American Industrial Hygiene Association Journal, Apr. 1976, Vol.37, No.4, p.239-245. Illus. 7 ref.


CIS 77-974 Tobias J.V.
Earplug rankings based on the protector-attenuation rating.
A method is proposed aimed at evaluating the effectiveness of ear protectors by a simple numerical rating instead of the rating in dB, which is liable to be misinterpreted. This protector-attenuation rating is based on a 3-digit classification of the mean attenuation and the standard deviation. The test procedure used is the ANSI method for the measurement of ear protectors at threshold. Attenuation spectra of 47 earplugs are reproduced and rated by the proposed classification. The results are tabulated and discussed.
AD-A024 756/9WV, National Technical Information Service, Springfield, Virginia 22151, USA, Oct. 1975. 65p. 17 ref. Price: Photocopy US-$4.50/Microfiche US-$2.25.

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