GBZ/T 229.4-2012Classification of occupational hazards at workplaces - Part 4: Occupational exposure to noise (English PDF)

4.1 Classification principles and basic requirements

4.1.1 Classification basis

The noise classification is based on the national occupational health standard exposure limits and measurement methods.

4.1.2 Preparation before classification

On-site inspections shall be conducted to identify the source and distribution of industrial noise at workplaces, the exposure of workers to noise and the adopted control measures; historical hearing impairment data shall be collected to determine the tasks that need to be classified.

4.1.3 Classification control effect evaluation

In accordance with the requirements for evaluation and monitoring of occupational hazard factors, the workplace noise shall be monitored regularly;

when the intensity of exposure to noise changes, which suggests that it may be inconsistent with the original classification results, or when there are changes in the production process, raw materials, equipment, etc., the classification shall be re-taken, and new preventive control measures and recommendations shall be put forward.

4.1.4 Classification data management

4.1.4.1 After the classification is completed, a workplace noise classification report shall be prepared. The content of the report shall include the classification basis, methods, results, and classification management recommendations and the objects that shall be notified.

4.1.4.2 The classification results shall be notified to the relevant managers of the employer, workers and relevant government departments.

4.1.4.3 All data of the classification process shall be archived and stored.

4.2 Classification basis

5.1 For workers with 8h/d or 40h/week noise exposure equivalent sound level

>=80 dB but < 85 dB, health monitoring shall be carried out if the current operation method and protective measures remain unchanged. Once the operation method or control effect changes, it shall be reclassified.

5.2 Mild hazard (class I): Under current working conditions, it may have an adverse effect on the hearing of workers. The working environment shall be improved; the actual exposure level of workers shall be reduced; noise hazard and protective signs shall be set up; noise protective equipment shall be worn;

occupational health training shall be provided for workers; occupational health monitoring, regular workplace monitoring and other measures shall be adopted.

5.3 Moderate hazard (class II): Under current working conditions, it is likely to have an adverse effect on the hearing of workers. According to the characteristics of the enterprise, while taking the above measures, corrective and management actions shall be taken to reduce the actual exposure level of workers.

5.4 Severe hazard (class III): Under current working conditions, it will have an adverse effect on the health of workers. In addition to the above measures, engineering and technical measures shall be taken as far as possible, for corresponding rectification. After the rectification is completed, the occupational health assessment and noise classification of the workplace shall be re- evaluated.

5.5 Extremely severe hazard (class IV): Under current working conditions, it will

have a negative impact on the health of workers. In addition to the above measures, appropriate engineering and technical measures shall be taken in time for rectification. After the rectification is completed, the control and protection effects shall be evaluated for health and noise classification.

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