Noise Control of Buildings

Introduction

 The acoustical design issues for buildings involve the principal issues like site noise considerations, including the control of noise transfer to a project’s neighbours, particularly if they are residential, establishing noise standards for each use space, including limitation of excessive ventilation noise, room acoustics considerations, sound isolation between various use spaces, vibration control for mechanical equipment, audio/visual system considerations.

Wall Construction

A standard partition used to separate rooms in a building is typically a single stud wall and one layer of gypsum board on each side, and it has an STC rating of 35. The acoustic performance of the standard wall can be improved by using light gauge (25 gauge) metal studs instead of wood studs. There are some conditions in a library where more sound isolation will be required, which can be accomplished by adding insulation within the wall cavity, providing a second layer of gypsum board on each side of the partition, or possibly using staggered stud construction. These program areas include conference rooms and offices requiring confidential speech privacy, where STC ratings in the range of STC 45-50 are recommended. To control noise transfer from rooms having amplified sound systems such as meeting rooms into other library spaces, the surrounding walls should have a minimum rating of STC 55-60.

Sound and Noise

 Sound waves in air result from a physical disturbance of air molecules, such as when a truck drives by a building or when guitar strings are plucked. Sound waves combine and reach a listener via numerous direct and indirect pathways. The listener’s inner ear contains organs that vibrate in response to these molecular disturbances, converting the vibrations into changing electrical potentials that are sensed by the brain, allowing hearing to occur.

Noise Control of Mechanical and Electrical Systems

When designing a building, it is important to control the noise and vibration of its mechanical and electrical equipment. Without adequate consideration during design, the very equipment that provides thermal comfort and electrical power can generate annoying noise and vibration. Proven techniques are available for mitigating noise and vibration from this equipment. 

 Conclusion

As the architectural and engineering design of the project evolves, the design should be reviewed in light of the agreed upon acoustical programmatic requirements for the building project. Since acoustics is typically not a code requirement, a city or state building official cannot be expected to comment on the correctness of the acoustical design in the contract documents.