217 Internet Assignment4 Francois Guilbault 2014f

This assignment consists of four parts: A, B, C and D for a total of 11% of the course mark. The worth of each part of the assignment in terms of the % grade of the total course mark is individually indicated. Please refer to the Blackboard link Course Materials - Course Outline – Quizzes, Assignments and Exam Details and Course Schedule about completion, due date and submission of this assignment.

Part A: Module 10 – Noise

I. Short-Answer Questions (2.5% of total course mark)

1. What is the normal hearing sensitivity of a healthy young person in terms of
i. Frequency range : 20Hz – 20.000Hz ii. Sound pressure: 0,00002 N/m2 – 200 N/m2

2. Describe the equation used for the calculation of sound pressure level. What is the unit used to express SPL?
It is a logarithmic ratio between a measured quantity and the reference and the threshold of hearing. SPL=20logP P∘
Unit is dB (decibel)

3. Give meanings to these terms:
i. A-weighting network: a calculation algorhythm included in sound level meters that targets some frequencies more than others. A network is specific in calculating occupational noise exposure. ii. Exchange rate: is a method the allowed exposure time when the exposure level increases under a given criterion level. iii. Criterion level: it’s the level permitted for a full 8-hour work shift per day.

4. Name the factors that affect the degree and extent hearing loss. Among these, which of them are considered in the setting of occupational noise exposure criteria?
Intensity of noise
Frequency characteristics of noise
Duration of exposure per day
Total work duration
Individual susceptibility
Age of the worker
Coexisting hearing loss and ear disease
Non-occupational noise exposure

5. Briefly explain these performance characteristics of a sound level meter:
i. Type 1 and 2: type 1 is for precise measurements in the field and type 2 is general purpose measurements ii. Slow/Fast/Peak response: the slow meter response uses an