1. Three workers (8-hour work shift) were monitored for work in different areas of a facility using calibrated noise dosimeters. The results are summarized in the following table.

Time for Monitoring Worker 1 Worker 2 Worker 3
3 hours 80.5 dBA 98.5 dBA 92.5 dBA
2 hours 81.0 dBA 86.5 dBA 85.0 dBA
2 hours 82.0 dBA 84.5 dBA 83.5 dBA
1 hour 95.0 dBA 83.5 dBA 80.0 dBA
2.

3.
a. Calculate the 8-hour time-weighted average (TWA) noise exposure for each of the three workers.
4. b. Summarize which (one) of the exposures exceeds OSHA's permissible exposure limit (PEL) and/or action level for noise.
c. Discuss what factors about the noise monitoring may have affected the accuracy of the noise measurements.

Show your work for all mathematical calculations. Please refer to Appendix A to 29 CFR 1910.95 for assistance on how-to solve this problem

To calculate the 8-hour time-weighted average (TWA) noise exposure for each worker, you need to follow these steps:

1. Convert the noise measurements from dBA to dB. This step is not explicitly mentioned in the question, but it is necessary as the TWA calculation requires the noise levels in dB.

2. Calculate the TWA for each worker using the formula:
TWA = 10 * log10((T1 * C1 + T2 * C2 + T3 * C3 + ... + Tn * Cn) / Ttotal)
where T is the duration in hours and C is the noise level in dB.

Let's perform the calculations for each worker:

Worker 1:
TWA = 10 * log10((3 * 80.5 + 2 * 81.0 + 2 * 82.0 + 1 * 95.0) / 8)
TWA = 10 * log10(241.5 + 162 + 164 + 95) / 8)
TWA = 10 * log10(662.5 / 8)
TWA = 10 * log10(82.81)
TWA ≈ 89.77 dB

Worker 2:
TWA = 10 * log10((3 * 98.5 + 2 * 86.5 + 2 * 84.5 + 1 * 83.5) / 8)
TWA = 10 * log10(295.5 + 173 + 169 + 83.5) / 8)
TWA = 10 * log10(721 / 8)
TWA = 10 * log10(90.13)
TWA ≈ 93.56 dB

Worker 3:
TWA = 10 * log10((3 * 92.5 + 2 * 85.0 + 2 * 83.5 + 1 * 80.0) / 8)
TWA = 10 * log10(277.5 + 170 + 167 + 80) / 8)
TWA = 10 * log10(694.5 / 8)
TWA = 10 * log10(86.81)
TWA ≈ 90.01 dB

Now, let's summarize which exposure exceeds OSHA's permissible exposure limit (PEL) and/or action level for noise.

According to OSHA's standards outlined in Appendix A to 29 CFR 1910.95, the permissible exposure limit (PEL) is 90 dB for an 8-hour shift, and the action level is 85 dB.

Comparing the TWA values we calculated:

Worker 1: TWA ≈ 89.77 dB (Below PEL and action level)
Worker 2: TWA ≈ 93.56 dB (Exceeds PEL, but below action level)
Worker 3: TWA ≈ 90.01 dB (Below PEL, but above action level)

So, Worker 2 is the only exposure that exceeds OSHA's permissible exposure limit (PEL). Workers 1 and 3 are below the PEL but Worker 3 is above the action level.

Finally, let's discuss the factors about the noise monitoring that may have affected the accuracy of the noise measurements.

Several factors can affect the accuracy of noise measurements, including:

1. Calibration of the noise dosimeters: The accuracy and calibration of the dosimeters used for monitoring is essential. If the dosimeters are not properly calibrated or maintained, the measurements may be inaccurate.

2. Placement of the dosimeters: The dosimeters should be placed in a representative location near the workers' ears to reflect their actual exposure. Placing the dosimeters too far away or in an incorrect position can lead to inaccurate readings.

3. Noise variability: Noise levels can vary throughout the work shift, and the measurements taken may not capture all the variations accurately. If there were significant fluctuations in noise levels that were not accounted for, the calculated TWA may not fully represent the exposure.

4. Background noise: Background noise present in the work environment can influence the measurements. It is important to subtract or account for background noise to obtain accurate measurements of the specific noise exposure relevant to the workers.

These are some of the factors that can affect the accuracy of noise measurements taken during monitoring. It is important to consider these factors and follow proper measurement procedures to ensure accurate results.