Assessment of Noise Exposure Levels in the Workplace

The relevance of efforts to reduce the impact of harmful and hazardous factors on employee health is driven by the fact that the primary cause of disability and death from occupational factors is not industrial accidents, but occupational diseases, which account for up to 80% of cases (according to WHO data).

Information on the compliance of labor process factors at workplaces with established standards can be obtained from Special Assessment of Working Conditions (SAWC) materials and Laboratory Control Program (LCP) data.

This year, our company conducted an occupational health risk assessment for employees. The assessment was based on long-term monitoring results of noise exposure levels from SAWC and LCP materials, as well as employee health data.

During the work, workplaces requiring risk reduction measures were identified, these measures were ranked by urgency, and proposals were developed for specific workplaces and professions. The theoretical assessments obtained are supported by factual material; therefore, we believe it is possible to recommend this approach to other enterprises.

When comparing long-term test results of noise exposure levels at the same workplaces, the low repeatability of results drew attention. In more than 60% of cases, the same workplaces had different assessments, and this issue required special study.

It was revealed that the difference in measurement results is due to several reasons: measurements were taken at different stages of the technological process; the choice of measurement strategy; limitations of measuring instruments and the time frames of the studies.

Today, the main methodological document in the field of noise level measurement in the workplace is GOST ISO 9612-2016. In accordance with this standard, monitoring of acoustic exposure levels on workers is carried out within the framework of industrial control and SAWC, based on the choice of measurement strategy. One of the features determining the choice of strategy is the period of time spent on measurement. For example, with a strategy based on job function, the minimum total duration of measurements is 5 hours, and with a strategy based on the working day — 3 work shifts, which makes performing measurements using a "classic" integrating-averaging sound level meter a difficult task.

Noise levels in workplaces are generally unstable during a work shift; therefore, measuring noise using a task-based strategy creates risks of unreliable values at workplaces and, consequently, an incorrect assessment of working conditions regarding the "industrial noise" factor, and a lack of a real picture of the noise load at the workplace. Ultimately, this affects the development of targeted preventive measures for health risk management and leads to inefficient spending of company funds.

Experience in measuring industrial noise using personal monitoring devices has shown that it is precisely the strategies based on job function or the working day that provide a reliable and complete picture of both the noise level at the studied workplace and the noise load on a specific employee, allowing for increased accuracy in assessing the class of working conditions.

The study proved that at workplaces where the noise level corresponds to working condition class 3.2 and higher, it is advisable to use personal monitoring devices.

It is important to note that when drawing up a program to reduce the risk level from noise exposure, it is necessary to take into account the measurement results of whole-body and hand-arm vibration levels at workplaces. This is necessary to assess the combined effect of vibroacoustic factors (noise, infrasound, vibration) at these workplaces, which have an additive (reinforcing) impact effect.