Basic concepts
Acoustics is defined as the “Science of sound”, Understanding sound as a mechanical disturbance in an elastic and inertial medium. These disturbances or oscillations of air pressure are converted into mechanical waves which excite the auditory mechanism, resulting in a perception.
Perceived sound is defined by:
Frequency
It represents the number of times a particle repeats a full cycle. The spectrum is the distribution of the energy between the different component waves.
Propagation Velocity
The speed at which the wave is propagated in the medium. In the air it has a velocity of 331.5 m/s to 0 ºC.
Sound Pressure Level (SPL)
It represents the intensity of the sound generated by a given pressure, which corresponds to what we finally hear, measured in decibels (dB). Varies from 0 dB (hearing threshold) to 120 dB (Pain threshold).
Noise
Noise is unwanted, annoying or irritating sounds, which occur when the listener is mentally or physically maladapted to the source that produces it. Any sound can be noise under certain conditions.
In the construction industry noise is classified as:
Airborne
Structural
Acoustic pollution
In a society focused on achieving the well-being of people at all levels, the impact of “acoustic pollution” and the development of protection methods to reduce it is increasingly important. This pollution originates both in and outside the buildings, altering the normal conditions of the environment in a given area and generating direct consequences on our health.
Rolled traffic
125 000 000
Some 125 million people affected by traffic levels of more than 55 dB (Lden). That is one in four Europeans.
Discomfort
20 000 000
Europeans affected by environmental noise
Sleep interruption
8 000 000
Europeans affected by environmental noise
Health impact
43 000
Europeans are hospitalised each year due to environmental noise
Premature death
10 000
Hypertension and cardiovascular diseases caused by environmental noise