Assignment 3
Due: 20 October
Value: 20%
1. Explain why a logarithmic scale is used to describe and compare sound levels.
[10 marks]
2. Noise calculations
a) Four different machines in a factory have noise levels of 88dB, 90dB, 90dB and 96dB respectively. What is the overall noise level? If the loudest machine was taken out, what would the resulting overall noise level be for the 3 remaining machines?
b) A group of workers are exposed to varying noise levels as different machines in their workplace are used. Determine:
i. The Total Daily Noise Exposure (Pa2.h) ii. The Noise Exposure Level (LAeq.8h) iii. The class of hearing protection that should be used, if appropriate.
Time Sound level dB(A)
8.00 am – 10.00 am
10.00 am – 10.30 am
10.30 am – 1.00 pm
1.00 pm – 1.30 pm
1.30 pm – 2.00 pm
2.00 pm – 4.00 pm 85
83
88
80
97
92
[15 marks]
3. The most important effect of excessive noise exposure in the workplace is the risk of noiseinduced hearing loss. However, there may be other effects of noise in the workplace. What might some of these be? Describe and discuss.
[20 marks]
4. For two (2) different types of non-ionising radiation, outline some control strategies for a specific workplace exposure to each type, and group these according to the control hierarchy.
[15 marks]
5. Write short reports on two biological hazards which workers may be exposed to in specific workplace settings. You should write about one bacterial infection and one viral infection.
You should give a brief description of the biological agent then use the following headings:
• occupational setting and workers at risk
• routes of transmission and infective process
• prevention and control measures
Your reports should not exceed two pages for each substance. You should summarise and explain the key information clearly and simply. Reference your sources but do not attach this material.
[40 marks]
Total: 100 marks