Bruit et vibrations

Cardiovascular Risk in Rotogravure Industry

Maryse Gagnon — Fri, 11 May 2012 17:37:00 GMT

Objective: To verify whether the occupational hazards in the rotogravure industry can be associated with cardiovascular effects.
Methods: We evaluated cardiovascular parameters and audiometric tests and analyzed noise, solvents, and shift work in 44 exposed and 44 unexposed workers.
Results: Unlike unexposed workers, the rotogravure workers showed significant increase of mean systolic and diastolic blood pressure (BP) values (P = 0.019; P = 0.003), higher frequency of hypertension (P = 0.002) and electrocardiographic abnormalities (P = 0.0001), significant reduction or no variation of BP response to orthostatism (P = 0.0001), and association between high levels of noise and diastolic blood pressure (P = 0.0067). Subjects with hearing loss showed high frequency of hypertension and a reduction or no variation of BP response to orthostatism (both P = 0.05).
Conclusions: Data obtained suggest that these are the effects on the cardiovascular system of rotogravure workers who are exposed to noise.

Source : Sancini, Angela PhD; Tomei, Gianfranco PhD; Vitarelli, Antonio MPH; Caciari, Tiziana MD; Samperi, Ilaria MD; Pacchiarotti, Alessandro MD; Scala, Barbara MD; Schifano, Maria Pia MD; Scimitto, Lara MD; Fiaschetti, Maria MD; Cetica, Carlotta MD; Tomei, Francesco MPH; Ciarrocca, Manuela PhD. Journal of Occupational & Environmental Medicine: May 2012 - Volume 54 - Issue 5 - p 551–557.
http://dx.doi.org/10.1097/JOM.0b013e318247a42d

Whole body- vibration (WBV) levels remained just above ISO 2631-1 after being optimized for load-haul-dump (LHD) vehicles

Jacqueline Caboret — Tue, 08 May 2012 15:41:00 GMT

Operators of load-haul-dump (LHD) vehicles are commonly exposed to wholebody- vibration (WBV) levels above ISO 2631-1 and EU Directive 2002/44/EC guidelines. Vibration exposure was lowest when the LHD was driven at the lowest speed, forward, over smooth terrain, with ride control on and the bucket loaded (0.20 m/s²). The A(8) decreased from 0.84 m/s² when driving with ride control off, over mixed terrain using all gears, to 0.53 m/s² when driving with ride control on and an optimized seat. The estimated daily exposure decreased but remained just above the ISO 2631-1 and EU Directive 2002/44/EC guidelines.

Source : Edger, T.R., Contratto, M.S., Dickey, J.P. Influence of Driving Speed, Terrain, Seat Performance and Ride Control on Predicted Health Risk Based on ISO 2631-1 and EU Directive 2002/44/EC. Low Frequency Noise, Vibration and Active Control, Vol. 30, Number 4/ December 2011.

http://dx.doi.org/10.1260/0263-0923.30.4.291

While awaiting the new EPA's labeling regulation, train users to fit protectors correctly

Jacqueline Caboret — Fri, 04 May 2012 19:09:00 GMT

EPA's final rule regarding hearing protection labeling is still pending. The proposed rule changes the very heart of the Noise Reduction Rating (NRR). The new NRR will be a range that is reported from very different testing methods than the old (current) NRR. These proposed labels do provide more information for the consumer but might also lead to some confusion. Knowing what kind of hearing protectors are best for a given situation will help understand the information provided on the new labels. The proposed method for labeling hearing protector includes the obvious but often misunderstood concept that "The sound pressure level at the user's ears will depend upon the fit of the protector." The best way to use the time while we're awaiting the new regulation on labeling of hearing protectors is to train users to fit the protector correctly and to use fit testing to document the protection provided by a given hearing protector.

Source : Theresa Y. Schulz. HEARING PROTECTION: Hearing Conservation in 2012: Focus on NRR.Occupational Health & Safety. March 2012.

http://ohsonline.com/Articles/2012/03/01/Hearing-Conservation-in-2012.aspx

Dental personnel in Thailand are exposed to noise intensities lower than occupational exposure limits.

Jacqueline Caboret — Tue, 01 May 2012 14:23:00 GMT

This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ± 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory.

Source : Choosong, T. et al. Noise Exposure Assessment in a Dental School. Saf Health Work 2011 Dec;2(4):348-354.

http://dx.doi.org/10.5491/SHAW.2011.2.4.348

Reliability of the anti-vibration (AV) glove test defined in ISO 10819 (1996)

Jacqueline Caboret — Fri, 27 Apr 2012 14:13:00 GMT

The specific aims of this study are to examine the rationale behind the major revisions of the ISO standard of the anti-vibration (AV) glove test and to evaluate the major technical aspects of the revised method through an experiment. While this study failed to realize the constant-velocity spectrum proposed in the original revision, the glove vibration transmissibility values measured with a new spectrum proposed in the current study were very similar to those measured with the M and H spectra defined in the current standard, which suggests the new spectrum can greatly simplify the test without changing the original test results, and it should be adopted in the further revision of the standard. The authors noted that the glove that reduced the grip strength the least was also the one that reduced the most vibration, which suggests that the negative and positive effects of the glove can be balanced in its design.

Source : Welcome, D.E. et al. An evaluation of the proposed revision of the anti-vibration glove test method defined in ISO 10819 (1996). International Journal of Industrial Ergonomics; Volume 42, Issue 1, January 2012, Pages 143–155.

http://dx.doi.org/10.1016/j.ergon.2011.09.003

http://www.sciencedirect.com/science/article/pii/S0169814111001181

Wireless Communication : Good team communication under difficult and potentially dangerous conditions required

Jacqueline Caboret — Tue, 24 Apr 2012 13:53:00 GMT

Team communication is absolutely essential in creating a safe, productive and effective work environment. Ambient noise can dramatically affect the clarity of team communications. First responders may be subjected to deafening siren noise while en route to a rescue operation, but they are not alone. Many industries expose workers to high noise levels on the job. Airport ground personnel must contend with the roar of jet engines. Road and construction crews must communicate against a backdrop of heavy equipment. Factory workers must talk over the noise of a manufacturing plant. These seemingly unrelated situations all have one thing in common: they require good team communication under difficult and potentially dangerous conditions. Noisy environments not only make clear communication difficult, they also pose a threat of noise-induced hearing loss. OSHA regulations require hearing protection when the time-weighted average noise level exceeds 85 dB. Recent advancements in technology have made new wireless communication headsets the best practice for enabling communication in high-noise environments. Wireless headsets reduce background noise and allow teams of almost any size to communicate clearly and effectively. Properly designed and configured, wireless headsets also leave the wearer's hands free, provide freedom of movement and eliminate the possibility of injury from entangled cords. And, because wireless headsets do not need to be plugged into a stationary intercom, team members can stay in continuous contact with each other, even when in motion. Wireless headset and intercom systems are available in a wide variety of configurations and price ranges. This article presents how to ensure that a particular system is adequate and the factors to be carefully considered.

Source : Reed Stager. Wireless Communication: Selection & Use to Improve Team Safety. Professional Safety- Journal of ASSE; March 2012.

http://www.asse.org/professionalsafety/best-practices_story2.php

Voir aussi : International Association of Fire Chiefs. (2002). Crew resource management: A positive change for the fire service. Fairfax, VA: Author. Retrieved July 14, 2011, from www.iafc.org/files/pubs_CRMmanual.pdf. National Fire Fighter Near-Miss Reporting System. Retrieved July 14, 2011, from www.firefighternearmiss.com. National Fire Protection Association. (2007). NFPA 1500: Standard on fire department occupational safety and health program, §7.16. Quincy, MA: Author.

Population in Michigan is exposed to noise levels with possibility of long-term adverse effects on hearing

Jacqueline Caboret — Fri, 20 Apr 2012 13:15:00 GMT

A total of 73 000 person-hours of noise monitoring were conducted in this observation study. Median overall daily average levels were 79 and 77 dBLeq_A,8,equiv , with average levels exceeding EPA recommended levels for 70% of participants. The authors concluded that a large portion of the general population is exposed to noise levels that could result in long-term adverse effects on hearing. Gender and occupation were most strongly related to exposure, though most participants in this study had occupations that are not conventionally considered noisy.

Source : Flamme, G.A. et al. Typical noise exposure in daily life. International Journal of Audiology. February 2012, Vol. 51, No. S1 , Pages S3-S11 (doi:10.3109/14992027.2011.635316)

http://informahealthcare.com/doi/abs/10.3109/14992027.2011.635316

Le local a un rôle déterminant dans l'exposition au bruit des travailleurs

Jacqueline Caboret — Tue, 17 Apr 2012 15:55:00 GMT

Par la réverbération, le local augmente le bruit provenant des machines et affecte tout l'espace de travail. Le code du travail français fixe les caractéristiques minimales que doivent présenter les locaux. Ce document de l'INRS rappelle quelques aspects techniques, décrit comment qualifier un local, précise les exigences réglementaires et explique le principe et la mise en œuvre du traitement acoustique d'un local. Ce document annule et remplace la fiche pratique de sécurité ED 136 "Améliorer l'acoustique des locaux de travail", publiée en 2009.

Source : Traitement acoustique des locaux de travail. INRS, ED 6103, 2011.

http://www.inrs.fr/accueil/produits/mediatheque/doc/publications.html?refINRS=ED%206103

http://www.inrs.fr/default/dms/inrs/CataloguePapier/ED/TI-ED-6103/ed6103.pdf

A bit isolator and a chuck isolator reduce the noise radiated by the drill steel and chuck

Jacqueline Caboret — Fri, 13 Apr 2012 16:09:00 GMT

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response to this problem, the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) conducts research to reduce the noise emission of underground coal-mining equipment, an example of which is a roof bolting machine. Field studies show that, on average, drilling noise is the most significant contributor to a roof bolting machine operator’s noise exposure. NIOSH OMSHR has determined that the drill steel and chuck are the dominant sources of drilling noise. NIOSH OMSHR, Corry Rubber Corporation, and Kennametal, Inc. have developed a bit isolator that breaks the steel-to-steel link between the drill bit and drill steel and a chuck isolator that breaks the mechanical connection between the drill steel and the chuck, thus reducing the noise radiated by the drill steel and chuck, and the noise exposure of the roof bolter operator. This paper documents the evolution of the bit isolator and chuck isolator including various alternative designs which may enhance performance. Laboratory testing confirms that production bit and chuck isolators reduce the A-weighted sound level generated during drilling by 3.7 to 6.6 dB. Finally, this paper summarizes results of a finite element analysis used to explore the key parameters of the drill bit isolator and chuck isolator to understand the impact these parameters have on noise.

Source : Michael, R., Yantek, D., Johnson, D., Ferro, E. and Swope, C. Development of elastomeric isolators to reduce roof bolting machine drilling noise. Noise Control Eng. J. 59, 6, pp. 591-612 (2011)

http://dx.doi.org/10.3397/1.3659660

http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=NCEJD5000059000006000591000001&idtype=cvips&doi=10.3397/1.3659660&prog=normal

Clamping force and increased bulk increases discomfort and wearing difficulty for circum-aural hearing protectors

Jacqueline Caboret — Tue, 10 Apr 2012 15:47:00 GMT

The physical properties of circum-aural hearing protectors, such as mass, clamping force and cup volume, have an influence on the attenuation performance of the device. This paper closely examines the physical and acoustic properties 39 of hearing protectors readily available to all users. The results indicate that attenuation increases with clamping force up to a limiting value of around 11 Newtons above which expected increases in attenuation are very small for large increases in clamping force. Likewise increasing the (newly introduced term) bulk of a hearing protector (volume, mass and cup elements) increases the attenuation but, as with clamping force a limit is reached where increased bulk increases discomfort and wearing difficulty

Source : Williams, W., Seeto, M. and Dillon, H.The mechanical properties of earmuffs.Noise Control Eng. J. 60 (1), Jan-Feb 2012, p29-35

http://dx.doi.org/10.3397/1.3673768

http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=NCEJD5000060000001000029000001&idtype=cvips&doi=10.3397/1.3673768&prog=normal

Peak values not appropriate for predicting the discomfort caused by transient vibration and experienced by standing people

Jacqueline Caboret — Thu, 05 Apr 2012 20:24:00 GMT

For motions with high crest factors, the vibration discomfort of standing people tends to be underestimated by rms methods (with an exponent of 2) and overestimated by rmq methods (with an exponent of 4). The optimum evaluation method in this study with standing people exposed to fore-and-aft, lateral and vertical vibration had an exponent of about 3.0 for transient motions centred on 1 Hz and an exponent of about 3.5 for motions centred on 8 Hz. The findings of this study with standing people are broadly consistent with studies using different motions and different psychophysical methods with seated people.

Source : Olivier Thuong & Michael J. Griffin (2011): The vibration discomfort of standing persons: evaluation of random and transient motions, Ergonomics, 54:12, 1228-1239

To link to this article: http://dx.doi.org/10.1080/00140139.2011.624199

http://www.tandfonline.com/doi/pdf/10.1080/00140139.2011.624199

Low-pass filtered masking noise makes speech-in-noise tests more sensitive

Jacqueline Caboret — Mon, 02 Apr 2012 20:45:00 GMT

An easily accessible screening test can be valuable in the prevention of noise-induced hearing loss (NIHL). The Dutch National Hearing Foundation developed ‘Earcheck’, an internet-based speech-in-noise test, presenting CVC-words in stationary broadband noise. However, its sensitivity to detect NIHL appeared to be low, 51% (Leensen et al, 2011, part 1). This study showed that Earcheck with low-pass filtered noise made the best distinction between normal hearing and NIHL, without reducing test reliability. The use of this noise condition improved the sensitivity of Earcheck to 95%. Conclusion: The use of low-pass filtered masking noise makes speech-in-noise tests more sensitive to detect NIHL in an early stage.

Source : Monique C. J. Leensen, Jan A. P. M. de Laat, Ad F. M. Snik, and Wouter A. Dreschler. Speech-in-noise screening tests by internet, Part 2: Improving test sensitivity for noise-induced hearing loss. International Journal of Audiology, November 2011, Vol. 50, No. 11 : Pages 835-848
To link to this article: http://dx.doi.org/10.3109/14992027.2011.595017

Whole-body vibration : Typical postures of the drivers result in enhanced spinal forces compared with the upright sitting posture

Jacqueline Caboret — Thu, 29 Mar 2012 18:01:00 GMT

Typically drivers of container-bridge cranes are forced to sit with a forward bent upper trunk to control the position and motion of the container. Fork-lift truck drivers incline the upper trunk to the side to look forward or they twist to one side during reversing. The forces transmitted in the lumbar spine were assessed by means of a biomechanical model. Under realistic vibration stress the bent postures result in an increase of the compressive and the shear forces. The increase of the spine forces is the result of the increased muscle forces stabilizing the inclined trunk. On container bridge cranes or fork-lift trucks the typical postures of the drivers result in enhanced spinal forces compared with the upright sitting posture. This effect must be considered in the risk analysis of workplaces with whole-body vibration.

Source : Fritz, M., Schäfer^,K. Influence of the Posture of the Trunk on the Spine Forces During Whole-Body Vibration. Low Frequency Noise, Vibration and Active Control, Volume 30, Number 4 / December 2011, 277-290. DOI : 10.1260/0263-0923.30.4.277

http://multi-science.metapress.com/content/lqg0381h8770g5g3/fulltext.pdf

The bi-sound signal to be mandatory for track work (IFA): the perceptibility of the signals have been tested under working noise conditions

Jacqueline Caboret — Mon, 26 Mar 2012 14:33:00 GMT

Warning signal generators are used at points where track work is being carried out in order to warn workers of approaching trains on neighbour-ing lines, electroacoustic signal generators are generally employed. Harmonization of the warning signals would simplify instruction at the work site. In addition, the signal generators fitted on track-laying machines would not repeatedly have to be set to whichever warning signal is emitted by the signalling devices on the track being worked on.

In order to determine the perceptibility of the signals under working noise conditions, hearing tests were conducted on test subjects in the IFA's laboratory in conjunction with the responsible German Social Accident Insurance Institutions (those for the building trade and for the railway services), and with Deutsche Bahn AG. The comparison of signal pairs above the masked threshold revealed a clear preference for the Minimel signal at all signal levels. This result is also confirmed by the hearing tests performed with hearing protection worn. In a direct comparison, the Minimel signal can therefore be considered more suitable for track work than the Autoprowa signal. The products of both manufacturers are capable of producing this signal. DB Netz AG will issue a technical bulletin shortly announcing harmonization of the warning signals and a deadline for withdrawal of CO2 signal horns. This bulletin will make use of the bi-sound signal mandatory after 31 December 2013.

Source : Harmonized warning signal for track work. IFA 0334; Edition 12/2011; 617.0-IFA:638.21

http://www.dguv.de/ifa/en/pub/ada/ada01/index.jsp

http://www.dguv.de/ifa/en/pub/ada/pdf_en/aifa0334e.pdf

Study on the impact of exposure to noise in professional snipers

Maryse Gagnon — Tue, 20 Mar 2012 17:37:00 GMT

Facing an increasing violence level and higher firepower in the hands of criminal organizations (especially those related to drug trafficking), the Military Police of Pernambuco has created, in 1989, the “1a Companhia Independente de Operações Especiais” (1st Independent Company of Special Operations), as a tactical last resort of the Police to be used on special, complex situations. The CIOE progressively makes use of Negotiation measures, of less-than-lethal maneuvers, of Precision Shots and Tactical Assaults. When all possibilities are drained, the Precision Shot will bring the crisis perpetrator down. This study had as an objective to assess the level of impact noise suffered by the elite snipers of the 1st CIOE-PE in their training. The working conditions of the snipers were evaluated through the use of a semi-structured questionnaire. Noise measuring was done on four (4) .308 IMBEL AGLC (with ammo from the same lot) rifles. Six (6) shots were fired off each gun, separated by a 30-second pause. In the end, it has been concluded that the noise level the 1st CIOE snipers are submitted to is considered to be normal by Brazilian legislation.

Source : Barkokebas Junior B, Lago E, Vasconcelos B, Oliveira E. Work 2012. 41, p. 3269-3276.
http://dx.doi.org/10.3233/WOR-2012-0593-3269