9 HAZARD PREVENTION AND CONTROL …

1 9 HAZARD PREVENTION AND CONTROLPROGRAMMESDr Berenice I. F. Goelzer*World Health GENERAL CONSIDERATIONS Noise-induced hearing loss is, at present, incurable and irreversible, however, it is definitelypreventable, therefore the implementation of adequate preventive programmes is essential. Specific measures for the PREVENTION and CONTROL of exposure to noise are discussed in detailelsewhere in this document; however, it is important to keep in mind that such measures shouldnot be implemented in an ad hoc manner but as part of a comprehensive strategy. The objective of this chapter is to discuss basic principles for HAZARD PREVENTION and controlprogrammes and their management, relating them to the PREVENTION of noise exposure andassociated effects, whenever relevant. A programme to protect workers from the effects of hazardous noise exposure in theworkplace is often called a hearing conservation programme .

2 However, rather than an isolatedeffort, this should preferably be integrated into the overall HAZARD PREVENTION and controlprogramme of the workplace in question. HAZARD PREVENTION and CONTROL programmes should be designed to meet the specific needs ofeach situation, in view of the existing hazards and of the many other factors that characterize aworkplace; furthermore, programmes should be adaptable to new scientific and technologicaldevelopments, as well as to eventual changes in the socio-economic context. As previously seen, noise CONTROL programmes are often mentioned or defined by nationallegislation or international standardization. For example, the ISO 11690-1 states that: In order to reduce noise as a HAZARD in the workplace, individual countries have producednational legislation. Generally, national legislation requires the implementation of noise controlmeasures in order to achieve the lowest reasonable levels of noise emission and exposure, takinginto account:&known/available measures;&the state of the art regarding technical progress;&possibilities for noise reduction at the source;&appropriate planning, procurement and installation of machines and equipment.

3 Another example is the European Directive 86/188/EEC on noise at work which requiresappropriate hearing conservation and noise CONTROL programmes whenever a workplace falls intothe noisy category (according to the EU definition). _____*Present address: 26, ch. Colladon CH-1209 Geneva, Switzerland PREVENTION and CONTROL REQUIREMENTS FOR EFFICIENT PROGRAMMES HAZARD PREVENTION and CONTROL programmes require: political will and decision-making; commitment from top management, with a clear and well circulated policy basis; commitment from workers; well defined goals and objectives; adequate human and financial resources; technical knowledge and experience; adequate implementation and competent management of programmes; establishment of multidisciplinary teams; mechanisms for communication; monitoring mechanisms (indicators); continuous improvement of the will and motivation require awareness and understanding of the problems caused byhazardous exposure, in this case to harmful noise levels, as well as of the available preventionand CONTROL solutions and of the benefits resulting from their application.

4 At the workplace level, the decision-making process starts with the awareness and acceptancethat there is a problem; for example, a noise problem. This is followed by the recognition andlocalization of the noise sources and the conditions of exposure ( , duration). If there isobvious overexposure, a decision is already possible after this first step and the next stage willbe the planning of a preventive strategy. If a decision is not possible, the next stage will requirequantitative exposure assessments; for example, noise measurements. The decision-making ladder can be used to analyze the decision-making process concerninghazard CONTROL in workplaces, as well as to pinpoint where blockages occurred, or are likely tooccur, with a view to avoiding them (Antonsson, 1991). The steps in the ladder are:1. Be aware of the problem6. Know the supplier (of solution)2. Accept the problem7.

5 Finance3. Know the cause 8. Implement solutions4. Learn of possible solutions9. Evaluate5. Accept a solutionSo that efficient HAZARD PREVENTION and CONTROL programmes may be implemented, concernfor workers health should be included in the priorities of top management alongside productivityand quality. A clear policy, discussed, agreed upon and understandable by the stakeholders isessential. The objectives of the programme , the steps to be followed and the availablemechanisms for implementation should be clearly defined and presented to all concerned, whomust know what to expect and hope for; unrealistic and unattainable goals are very design and implementation of HAZARD PREVENTION and CONTROL programmes requireinvolvement and commitment not only from management, but from production personnel,workers and occupational health PREVENTION and CONTROL programme Recognition of the ProblemComplaints of hearing difficulties among workers is too late an indicator that a noise problemexists; however, should this happen, CONTROL action must be immediately triggered.

6 Therecognition of a noise problem should take place much earlier, whenever noise levels exceedacceptable limits, or simply whenever there is a feeling that the workplace is just too noisy,particularly if there is any interference with verbal communication. In fact, the best approach isto foresee problems and avoid them; for example, by selecting quieter equipment and processes,whenever recognition that a noise problem exists is followed by a qualitative assessment of thesituation, which includes identifying and localizing noise sources, defining noise exposurepatterns, including which are normal and which are unusual exposure conditions. In view of theirexperience with tasks, work processes, equipment and machinery, workers can provide valuableassistance in gathering such information, which is needed to design an adequate strategy for anysubsequent quantitative evaluations, in this case, noise Exposure Assessment IssuesAlthough strategies for noise surveys , including measurements and instruments, are presentedin detail in Chapter 7, some aspects are hereby summarized so that they may be put intoperspective as important elements of an overall noise PREVENTION and CONTROL hazards are obvious and serious - for example, a workplace where people close to eachother have to shout to be understood, the recognition of the problem must be followed by CONTROL ;quantitative evaluations will come later, in order to verify the efficacy of the CONTROL system.

7 Itmay sometimes be necessary to change the classical concept of "recognition-evaluation- CONTROL "to "recognition- CONTROL -evaluation". Decision-making as to CONTROL actions may have to rely onprofessional judgement and common sense, particularly if measuring equipment is not to carry out noise measurements should never be a blockage to correcting obviouslyhazardous situations. Measurements must be carried out in the most usual conditions; appreciable fluctuationsshould be fully appreciated. In fact, as discussed in chapter 7, particularly if there are appreciablenoise level fluctuations or workers move around, noise dosimeters offer the best monitoringsolution. In order to study noise sources and their relative importance as contributor to exposure,as well as to check the efficiency of implemented noise CONTROL measures, the best approach isto use integrating sound level meters, adequately positioned ( , at the operators ear position).

8 The initial noise survey constitutes a decision-making tool, and also provides base line datawhich, together with results from subsequent surveys, may serve as an indicator for futureevaluations of any implemented CONTROL surveys to assess workers exposure should be carried out by specialized professionals,for example, occupational hygienists or other occupational health professionals with specifictraining in noise measurements. Occupational hygiene technicians, if specially trained for thispurpose, provide valuable support. Workers collaboration is essential. 236 HAZARD PREVENTION and CONTROL Selection of Measuring Instruments The type of HAZARD to be evaluated and the purpose of the survey will determine the type and therequired reliability of the measuring equipment; for example, sound level meters. If qualitative,or semi-quantitative measurements are sufficient, or if preliminary surveys are a priority, it isuseless to spend money on very expensive and sophisticated if funds are available, equipment should only be purchased, if and when a real need hasbeen established, and, operational capabilities have been ensured, including competent personnelto properly operate, calibrate and maintain the a new programme is being developed, only basic equipment should be purchased initially,more items being added, as the need arises and personnel competencies are developed.

9 Whenselecting any occupational hygiene equipment, in addition to performance characteristics,practical aspects should also be considered, including:&portability&source of energy needed&calibration and maintenance requirements&availability of expendable supplies&conditions of use (including infra-structure and climate)If the above requirements are overlooked, and unfortunately they often are, the result may bethat expensive equipment is inadequately utilized, or not utilized at all. The importance ofroutine calibration cannot be over steps of the noise evaluation must be equally well planned and carried out; the completeprocedure must be considered as one, since no chain is stronger than its weaker link . It wouldbe a waste of resources to allow for unequal quality in the different steps of a same noiseevaluation. For example, results obtained with a very accurate and precise integrating sound levelmeter might not be reliable if it had not been properly calibrated, or, the results might be far fromrepresentative of the workers' exposure, if the measuring strategy had not been adequatelydesigned and followed.

10 CONTROL Strategies and MeasuresAny HAZARD PREVENTION and CONTROL programme involves measures related to the workenvironment and measures related to the workers. Efficient CONTROL strategies usually rely on acombination of engineering (technical) CONTROL measures ( , quieter equipment and enclosures)and health/personal measures ( , work practices). Noise PREVENTION and CONTROL strategies usually involve elements from the following groupsof measures, that is, measures which relate to:&the work process (including tools and machinery), for example: quieter equipment, goodmaintenance;&the workplace, for example: noise enclosures or acoustic treatment, and, &the workers, for example: work practices and other administrative controls , audiometry,hearing protection and workers education. CONTROL measures should be realistically designed so as to meet the needs of each particular237 HAZARD PREVENTION and CONTROL programmessituation and the different options should be considered in view of factors such as effectiveness,cost, technical feasibility, socio-cultural CONTROL hierarchy should be the following: CONTROL of the noise source CONTROL of the noise propagation CONTROL at the worker levelThe standard ISO 11690 (part 1) provides more details on this hierarchy, in its clause on theconcept of noise reduction, as follows: Noise CONTROL can be implemented using various technical measures (see ISO 11690-2) andthere may be several ways to solve a noise problem.