# Noise Pollution Chapter 16 - PowerPoint PPT Presentation

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Noise Pollution Chapter 16. What’s the difference between a sound and a noise? (Intro & Section 16.3). Pressure Waves (Section 16.1). Source. Sound Pressure Level. SPL = 10 log (P 2 /P o 2 ) P o = 0.00002 Pa Units: dB. Typical SPLs.

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Noise Pollution Chapter 16

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## Noise PollutionChapter 16

Source

### Sound Pressure Level

SPL = 10 log (P2/Po2)

Po = 0.00002 Pa

Units: dB

### Typical SPLs

Measurements by Gordon Hempton, “an acoustic ecologist and sound recordist”

### Changes in Sound Energy

For n sources of the same dB:

SPLTotal = 10 log n + SPLo

### In-Class Activity

Your company is purchasing an additional piece of manufacturing equipment. You have two choices. One brand generates 91 dB(A); another brand costs 10% more but generates 88 dB(A). You determine that the current level of noise in the production area is 88 dB(A). The workers are on 8-hour shifts. The OSHA 8-hour noise limit for the area is 93 dB(A). The company has been doing well and has thoughts of expanding production at this location in the near future. Determine which piece of equipment to purchase.

Point Source

Line Source

### Effect of Distance

• Point source:  SPL = 20 log (D/Do) 6 dB/DD

• Line source:  SPL = 10 log (D/Do) 3 dB/DD

• Hard site: SPL = 10 log (D/Do) 3 dB/DD

• Soft site: SPL = 15 log (D/Do) 4.5 dB/DD

### Calculating SPL

SPL average from a frequency analysis

N = number of measurements taken

Leq

SPL

Time

Time Varying SPL

### Noise Abatement and Control(Sections 16.4 and 16.5)

Who regulates noise levels?

### Noise Abatement and Control

What are some options for abating or controlling traffic noise?

### Some Info about Noise Barriers

• How effective are they?

• When are they considered?

• When are they installed?

• Of what are they constructed?

1985

1984