Building Acoustics

The science and engineering of achieving a good sound environment within a building space.

Building acoustics design is achieved by following an “intelligent layout” where noise producing areas are separated from noise sensitive areas. Acoustics design should also ensure sound insulation between rooms and sound absorption of excess sound to improve communication and reduce noise related distraction.

What is Acoustics in Building science?

Sound Insulation

Reducing sound transmission between adjacent rooms

Sound Insulation is the reduction of sound (decibel level) as it passes through a partition. A partition can be a wall, ceiling or floor. The passage of sound into one room of a building from a sound source located in another room or outside the building is termed ''sound transmission".

For good sound insulation, the partition must be capable of blocking airborne sound and the construction must ensure no gaps and leaks using which sound can travel around the partition.

STC or Sound Transmission Class is a single number rating given to partitions which indicate the degree of sound transmission loss offered. A higher STC corresponds to a greater degree of sound insulation.

Sound Absorption Building Acoustics Model

Sound Absorption

Reducing noise within a room through absorbing

When sound meets a surface, a part of it is absorbed. The percentage of sound that is absorbed by a material is defined as the ‘Absorption Coefficient’ which is expressed on a scale 0-1. Sound absorption is important because it reduces sound levels inside a room.

Noise Reduction Coefficient (NRC):
Sound absorption of a material varies with the frequency of sound. Noise Reduction Coefficient is the mathematical average of absorption coefficient of a material at four frequency bands - 250, 500, 1000, 2000 Hz

Acoustics In Open Plan Offices

The open plan office model has been widely adopted by companies in India and across the world. Although this new model creates an open work environment, it continues to face criticism regarding its acoustic qualities. Some advantages and disadvantages are:

Advantages

  • Encourages team work and transparency
  • Encourages a horizontal hierarchy
  • Cost effective and easier to refurbish

Disadvantages

  • High levels of distraction due to people speaking, phones ringing, etc.
  • Poor environment for higher cognitive tasks such as problem solving and trouble shooting
  • Poor levels of privacy

The three key steps to good office acoustics are:

Sound Absorption: Reducing excess noise within an office by using sound absorptive materials for internal surfaces and furniture. Reduced noise improves communication between employees and also reduces noise related distraction.

Sound Insulation: Reducing sound transmission through walls, ceilings, doors and windows is essential for privacy.

Zoning: Intelligent layout of an office space keeping acoustics in mind. Often, materials are not the solution but an intelligent layout is.