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1

Facilities for Music Education and Their Acoustical Design

Koskinen H., Toppila E., Olkinuora P.

International Journal of Occupational Safety and Ergonomics

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2010

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Vol. 16, No. 1

93--104

EN

Good rehearsal facilities for musicians are essential. Directive 2003/10/EC necessitates that musicians are protected from noise exposure. A code of conduct gives the guidelines how this should be done. This study examines room acoustics recommendations provided by the Finnish code of conduct, and discusses whether they are adequate. Small teaching facilities were measured after renovation and compared to earlier measurements. Teachers’ opinions were inquired about the facilities before and after. The renovation did not decrease the noise exposure of the teachers. However, the majority preferred the facilities after the renovation. The Finnish code of conduct is not sufficient for facilities where loud instruments are played, or band practise. Good facilities can be designed but they must be specified at the designing stage for their intended use.

2

The Influence of Selected Risk Factors on the Hearing Threshold Level of Noise Exposed Employees

Dudarewicz A., Toppila E., Pawlaczyk-Łuszczyńska M., Śliwińska-Kowalska M.

Archives of Acoustics

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2010

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Vol. 35, No. 3

371-382

EN

The aim of the study was to evaluate the combined effect of noise exposure and additional risk factors on permanent hearing threshold shift. Three additional risk factors were: exposure to organic solvents, smoking and elevated blood pressure. The data on exposure and health status of employees were collected in 24 factories. The study group comprised of 3741 noise male exposed workers of: mean age 39§8 years, mean tenure 16§7 years and LEX;8h = 86 § 5 dB. For each subject, hearing level was measured with pure tone audiometry, blood pressure and noise exposure were assessed from the records of local occupational health care and obligatory noise measurements performed by employers. Smoking and solvent exposure were assessed with questionnaire. The study group was divided into subgroups with respect to the considered risk factors. In the analysis, the distribution of hearing level of each subgroup was compared to the predicted one which the standard calculation method described in ISO 1999:1990. For each of the considered risk factors, the difference between measured and calculated hearing level distribution was used to establish, by the least square method, a noise dose related correction square function for the standard method. The considered risk factors: solvent exposure, smoking and elevated blood pressure combined with noise exposure, may increase degree of hearing loss.

3

Evaluation of the Increased Accident Risk From Workplace Noise

Toppila E., Pyykko I., Paakkonen R.

International Journal of Occupational Safety and Ergonomics

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2009

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Vol. 15, No. 2

155--162

EN

Directive 2003/10/EC sets the requirement for evaluating the effect of noise on accident risk. Accident risk is elevated for workers with a hearing handicap because of their reduced speech intelligibility and reduced capability to perceive the direction of incoming sound. An audiogram is not a good method for the evaluation of these functions. To reduce accident risk, organisational and personal solutions are needed. For both methods, efficiency must be evaluated through proper risk assessment. Because practical guidelines are not available, this paper presents principles for accident risk evaluation techniques.

4

The attenuation of hearing protectors against industrial impulse noise

Starck J., Toppila E.

Mechanika / Akademia Górniczo-Hutnicza im. St. Staszica

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2004

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T. 23, z. 2

297-305

EN

Attenuation of hearing protectors is related to the working conditions, as well as qualitative and quantitative properties of noise. For steady state noise, methods presented in the standard are fairly applicable to assist {or allow for} in hearing protector proper selection. Pro- blems in application may arise in the case of impulse noise. Nonlinear effects in hearing protector response to shooting impulses has been shown, in which the nonlinearity and the decrease in attenuation occurred as the peak levels increased. The purpose of this study was to evaluate the characteristics of industrial noise and to find out what attenuation is provided by the selected earmuffs. The measurements were done using miniature microphone technique. For analyses of impulsiveness of industrial noise crest factor was used. The efficiency in protection determined for hearing protectors during laboratory type tests overestimated the real attenuation performance especially in extreme noise conditions. The double protection by earmuffs and earplugs will increase the attenuation especially at frequencies below 1000 Hz where the main frequency components occur in workshop noise.

PL

Tłumienie ochronników słuchu zależy od warunków pracy, a także od poziomu hałasu i jego charakteru. Metody przedstawione w normach mają dość dobre zastosowanie przy właściwej selekcji ochronników słuchu w przypadku hałasu ustalonego. Problemy pojawiać się mogą w przypadku hałasu impulsowego. Stwierdzono nieliniowość odpowiedzi ochronników słuchu na impulsy akustyczne pochodzące od strzałów z broni palnej. Nieliniowość ta wzrasta, przy czym maleje także tłumienie ochronnika słuchu, gdy szczytowe poziomy ciśnienia akustycznego ulegają zwiększeniu. Celem niniejszych badań była ocena charakterystycznych cech hałasu występującego w przemyśle i określenie, w jakim stopniu hałas jest tłumiony przez wybrane nauszniki przeciwhałasowe. Pomiary przeprowadzono z zastosowaniem techniki wykorzystującej mikrofony miniaturowe. Do analizy impulsywności hałasu w przemyśle zastosowano współczynnik szczytu. Skuteczność tłumienia ochronników słuchu określona podczas badań laboratoryjnych okazała się zawyżona w stosunku do ich skuteczności w warunkach rzeczywistych, zwłaszcza w przypadku ekstremalnych warunków hałasowych. Podwójne zabezpieczenie przez nauszniki przeciwhałasowe i wkładki przeciwhałasowe będzie zwiększać tłumienie w szczególnie w zakresie częstotliwości poniżej 1000 Hz, w którym występują główne składowe spektralne hałasu w przemyśle.

5

The attenuation of hearing protectors against high-level shooting impulses

Toppila E., Strack J.

Archives of Acoustics

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2004

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Vol. 29, no. 2

275-282

EN

The acoustical attenuation of five different hearing protectors were investigated using real impulses and miniature microphone technique in field conditions from a 23 mm antiaircraft cannon, from 122 mm howitzer and from an explosion of 1 kg of TNT. The measurements were carried out using voluntary military officers exposed to similar impulses in their work. The combination of earmuffs and earplugs proved to give the best attenuation. The attenuation of the earmuffs was related to the size of the cup. Light protectors gave practically no protection against the highest impulses from howitzer and TNT-blasts.