Statistics-Module 5 Homework Term

Module 5 Homework
Term:

Name:
Date: 22 Nov 15

In the event that you do not identify the correct answer, if you show your work and how you arrived at your
result, you may receive partial credit. However, if you do not show your work and the answer is not
correct, zero credit will be given for that problem. If additional attachments are necessary to show your
work, be sure to scan them in and attach before you click submit.

1. Suppose the sound pressure level of each of three individual noise sources is measured at a point
such that with each source running individually, the sound pressure is as follows (4 pts):
Source 1 - 88 dB
Source 2 - 86 dB
Source 3 - 91 dB
What is the sound pressure level with all three running? (Show your work).
88+86=90
90+91= 94
94 dB will be the sound pressure level with all 3 running
2. A compressor in a mechanical room was measured at 8 feet from the source to have a sound
pressure level of 92 dB. What would the sound pressure level be at 16 feet from the source? (2 pts)
3. A compressor in a mechanical room was measured at 8 feet from the source to have a sound
pressure level of 92 dB. What would the sound pressure level be at 4 feet from the source? (2 pts)
4. A compressor in a mechanical room was measured at 8 feet from the source to have a sound
pressure level of 92 dB.
a. If a second identical compressor was placed immediately next to the first, what would the
resulting sound pressure level measurement at 8 feet be? (2 pts)
b. If a third identical compressor was placed immediately next to the first two, what would the
resulting sound pressure level measurement at 8 feet be? (2 pts)
5. A mechanic must work in an area where three air-handling units are present. Each air handling unit
individually generates a sound level of 95 dB at 5 feet from the source.
a.

If the worker is positioned 20 feet from the first source, 10 feet from the second source, and
5 feet from the third source, and all three units are running continuously, to what sound level
is the worker exposed? Show all your work. (8 pts)

b. If the unit 20 feet from the worker is turned off and the other two are running, to what level is
the worker exposed? (2 pts)
c.

If the unit 5 feet from the worker is turned off and the other two are running, to what level is
the worker exposed? (2 pts)

d. Assuming all units are running and the worker’s job requires him or her to stay in that location
(20 feet from the first source, 10 feet from the second source, and 5 feet from the third

source) for 4 hours and work in another location with exposure below 65 dBA for the
remaining 4 hours, what is the 8 hour TWA of the exposure of the worker? (8 pts)
i. Does the employee need to be included in a hearing conservation program? Why or
why not (2 pts)
ii. Does the employee need hearing protection? Why or why not? (2 pts)
iii. If the worker does not have a threshold shift, under OSHA, to what level must an
employer attenuate exposure? (2 pts)
iv. If the worker has a threshold shift, under OSHA, to what level must an employer
attenuate exposure? (2 pts)
v. Identify at least one engineering, one administrative, and one protective equipment
control that could be implemented by the employer to reduce the worker’s exposure.
(6 pts)
vi. If the employer chooses to use protective ear plugs with an NRR rating of 25, to what
level (using the OSHA Technical Manual and Oregon OSHA method) would the
hearing protection attenuate the exposure? (6 pts)
6. If an employee is exposed to continuous sound levels for 3 hours at 94 dB and is then exposed to
sound levels of 80 dB for the rest of the 8-hour day, what is the employees’ 8 hour TWA in dB using
OSHA’s calculations? (8 pts)
a. Does this employee exceed OSHA’s PEL? (2 pts)
b. Does this employee need to be in a hearing conservation program? (2 pts)
7. An employee is working with a jackhammer that causes significant vibration in the hands and body.
Identify at least three potential health effects associated with exposure to this kind of vibration? (6 pts)
8. Identify at least three methods of minimizing the effects of vibration on a worker. (6 pts)
9. Given the following measurements taken in direct sunlight:
Globe Temp (F) 94
Dry Bulb Temp (F) 91
Natural Wet Bulb Temp (F) 83

a. What is the calculated WBGT in degrees Fahrenheit? (4 pts)
b. What is the calculated WBGT in degrees Celsius? (2 pts)
c.

What is the ACGIH range of recommended percent of work in a one to two hour cycle for
moderate work for acclimatized workers? (2 pts)

d. What is the ACGIH range of recommended percent of work in a one to two hour cycle for light
work for unacclimatized workers? (2 pts)
10. Given the following measurements taken in the shade:
Globe Temp (F) 92
Dry Bulb Temp (F) 95
SFTY 510 - M5 Calculation Assignment

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Natural Wet Bulb Temp (F) 88
a. What is the calculated WBGT in degrees Fahrenheit? (2 pts)
b. What is the calculated WBGT in degrees Celsius? (2 pts)
c.

What is the ACGIH range of recommended percent of work in a one to two hour cycle for
moderate work for acclimatized workers? (2 pts)

11. Given the following measurements:
Botsball reading: 81 (F)
Dry Bulb Temperature: 86 (F)
a. What is the calculated WBGT in degrees Fahrenheit? (4 pts)

b. What is the calculated WBGT in degrees Celsius? (2 pts)
c.

What is the ACGIH range of recommended percent of work in a one to two hour cycle for light
work for unacclimatized workers? (2 pts)

SFTY 510 - M5 Calculation Assignment

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