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9

PROTECTION

REQUIRED IF

EXPOSED FOR

8 HRS+

What is a Decibel?

Environmental Acoustics

design is based on

understanding the properties of sound.

Sound is a three-dimensional force. Much like expanding bubbles, sound waves

cause atmospheric changes, moving up, out and down equally and simultaneously

to cause changes in atmospheric pressure. These changes in pressure, or sound

pressure, and the intensity of that sound pressure, are what determine the intensity

level or loudness of a sound.

The sensation of hearing, produced by vibrating the eardrum, is due to these

small pressure changes. The sounds produced from these atmospheric changes

in pressure are measured in decibels (dB). The lowest sound pressure that can

be heard by humans is called the hearing threshold (0 dB). The highest that can

be endured is known as the pain threshold (120 dB). Sound pressure at the pain

threshold is a million times greater than that at the hearing threshold.

To understand how sound affects everyday life, it’s important to know where

common sounds fall in the decibel range between the hearing threshold and the

pain threshold:

– Normal office noise: 65 dB

– Lawn mower: 95 dB

– Crying baby: 110 dB

The science of environmental acoustics studies the characteristics and

performance of materials, products, systems and services related to sound

and the effects of sound on the surrounding environment. Choosing materials

or construction techniques that control, diminish or stop sound waves is the

cornerstone of Environmental Acoustics

design.

ENVIRONMENTAL ACOUSTICS™ DESIGN

100 dB

CD Player

0 dB

200 dB

25 dB Leaves Rustling

50 dB Rainfall

75 dB Traffic Noise

150 dB Firecracker

10 dB Soft Wind

20 dB Peaceful City

Apartment

40 dB Typing on

a Keyboard

60 dB Normal

Conversation

65 dB

Typical Office

90 dB Busy Traffic Noise

80 dB Hair Dryer

110 dB Crying Baby

95 dB Lawn Mower

120 dB

Rock Concert

140 dB

Engine Backfire

157 dB Balloon Pop

170 dB Shotgun Fire

170 dB Rocket Launch

NON-HAZARDOUS

85 dB

Smoke Alarm

EXTREMELY

LOUD

DAMAGE MAY

RESULT WITHOUT

PROTECTION

PROTECTION

REQUIRED

160 dB

Fireworks

PERFORATION

OF EARDRUM

POSSIBLE

Hearing damage may result

when exposed to decibel

levels above the pain

threshold – 120 dB – even

for short periods of time.