~&urnk* En pliant et rivetant les diff&ents parties de la structure des voitures, les marteaux pneumatiquies utilise's engendrent bruit et vibration. Le bruit produit par les six marteaux Gtudils dans une usine de fobrication de voiture est de type impulsive avec plus de vignt impulses par second. Le niveaux moyen de la pressoin cr&e est 131.9dB avec la deviation standard de 2.ldB. Le niveau equivalent pendant une journze de travail est 114 dB. La f vibration des mains a Ztg aussi evaluee dans

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... es 3 directions ( X ,~, Z ) . La direction z est la direction principale par laquelle la vibration entre les mains. La valeur efficace moyenne d'acceleration est 23.5 mIs2 avec la deviation standard de 15.2 mIs2. Le temps dkxposition total pendant la ~o u r n l e de travail est environ 6-30 minutesales r:sultats montrent que les 0 valeurs mesurLes ex&dent bien des valeurs limites proposes et le temps d&xposition permissible. Abstract When bending sharp and Jagged edges of materials and riveting different components of the cars structures, pneumatic hammers generate noise and vibration. The severity of the noise as a potential operator hazard should be considered in light of the following data. The noise produced by the six studied hammers is impact noise with more than 20 impulses per second. The average peak pressure level is 131.9 dB with the standard deviation of 2.1 dB. The equivalent level during a shift work, 8 hours per day, is 114 dB . Hand-arm vibration has also been measured in each applicable direction (xiy,z). The Z direction is the principal direction that vibration enters the hand. The average effective acceleration is 23.5 mIs2 and the standard deviation is 15.2 m/s2. The total exposure time during a shift is about 6-30 minutes which intermittently included 30-60 seconds. The measured levels correlate with operator exposures exceeding the allowable exposure time and the permissible values . This paper presents the assessment of sound pressure level and vibration acceleration magnitude produced b y the pneumatic hammers and tests a noise silencer that provided as much as 9 dB of noise reduction to the tool . Article published online by EDP Sciences and available at http://dx.