Noise and vibrations leave industry trembling
A typical day at the quarry: the wheel loader drives back and forwards to the impact crusher, tipping its load. For the driver it will be another long day on this heavy machine. But only if the seat is perfectly sprung. Otherwise, thanks to
EC directive 2002/44/EC “Vibrations” and 2003/10/EC „Noise“, there is a danger of the driver having to change over early.
The EC directives have been implemented in German law as the Noise and Vibration Workplace Protection Ordinance since 8.3.2007. But there is some doubt as to whether this ordinance has really arrived in the minds of the company managers and their employees. This inconspicuous ordinance is concerned with the impact of noise and vibrations on people. And it sets down how people can be effectively protected against these hazards to their health. It applies to hand-arm vibrations caused by a range of hand-held or hand-operated machines such as rock drills. It also covers vibrations affecting the entire body, as well as noise. These load factors can be experienced on numerous vehicles and work machines.
At the end of last year, surveys conducted by the occupational health and safety authorities in the administrative district of Upper Bavaria and in the State of Brandenburg showed that fewer than half of the Upper Bavarian companies where there is a vibration hazard were even aware of the ordinance at all. But the ordinance expressly specifies various situations as administrative offences. § 5 of the Noise and Vibration Ordinance specifies an expert to assess the hazard caused by noise and vibrations as a mandatory requirement. Finally, the results of the hazard assessment and the measures derived have to be documented. For this reason, the companies are well advised to take an intensive look at this issue.
The noise and vibration levels are based on an eight-hour working day. The ordinance clearly defines lower exposure limit values from which the employer is obliged to take action. Precisely defined upper exposure limits may not be exceeded. The company owner or manager is responsible for complying with these requirements. Monitoring of the measures is the responsibility of the Occupational Health and Safety authorities and the Employer’s Liability Insurance Associations.
The lower exposure limits can be very quickly reached, especially when driving over non-surfaced areas or rough tracks. It is a similar case with the noise load, depending on the source of the noise. One example of vibration load: as the catalogue of representative noise and vibration data, or KarLA for short (www.las-bb.de/karla), shows, on a trip with a wheel loader on rough terrain, the lower exposure limit is reached after just 78 minutes. After another five and a half hours, then wheel loader driver is finished for the day as the maximum exposure limit has been reached – and that despite a driving style described as appropriate. This can lead to the employees only being allowed to work with or on a particular machine for a certain number of hours.
It is advisable for companies to approach the responsible Employer’s Liability Insurance Association (Berufsgenossenschaft or BG) for a consultation. The right contact office there is the Technical Supervisory Service, also known as the Prevention Service in many BGs. The experts there know what aspects are important when it comes to protection against noise and vibrations. Generally, they also know how and where the required expert can be found if the company is too small to have its own appointed expert or a works doctor.
The determined acceleration values have to be assigned to every single employee according to the exposure time. It should be noted that this is rarely the same as the daily working hours and hours of use. For an eight-hour working day of a wheel loader driver, the exposure time is the time he actually spends driving. When he gets off the wheel loader, for example to refuel, this is classed as the usage time and not exposure time. If the lower exposure level is exceeded, the employer must arrange for an understandable briefing and instruction of the employees prior to them starting work. This must be repeated regularly. In addition, a general medical consultation as well as a preventative medical check-up must be made available. And the employer has to derive, define and conduct a programme of technical and organizational measures according to the state of the art. All this also has to be documented.
In addition, there is the option of using a vibration dosimeter (Fig. 1 and 2). Many manufacturers supply devices that also register the introduction of vibrations through the feet. With these devices, the actual circumstances can be analysed and documented very precisely, depending on the model. Numerous manufacturers are now aware of the problem and have responded accordingly. Handheld machines are available with effective anti-vibration protection, and for vehicles, seats with active vibration protection can push the lower exposure level much further off. It is therefore worth companies taking a closer look at their range of machines and fleet of vehicles.
To help companies compile an as realistic possible hazard assessment, a German-language brochure is available. It was updated at the beginning of the last year and is entitled “Ordinance on the protection of employees against noise and vibrations – a guide for working practice – especially for small to medium-sized companies”. Like many other work guides and catalogues of measured values, this can be downloaded as a pdf file at http://bb.osha.de, by clicking the button „Publikationen“. But from the same page, the guide can also be ordered free of charge from the State Office
for Occupational Health and Safety in the State of Brandenburg.
