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1. ACOUSTICS & SOUND
INSULATION
PREPARED BY:

2. CONTENT
 What is Acoustic?
 What is Sound?
 Characteristics of Sound
 Reflection of sound
 Absorption
 Sound Insulation
 Wall Insulation
 Floors and ceilings Insulation
 Noise Control in Residential Building

3. WHAT IS ACOUSTIC?
The word ‘acoustics’ is originally derived from a Greek word meaning ‘to hear’.
‘Acoustics is the science of sound, which deals with origin, propagation and auditory
sensation of sound. It also deals with designs and construction of different building units to
set optimum conditions for producing and listening speech, music etc.

4. WHAT IS SOUND?
Sound is generated in the air when a surface is vibrated. The vibrating surface setup waves of
compression and rarefraction in the air and these set the ear drum vibrating. The movements
of the ear drum are translated by the brain into sound sensation.

5. WHAT IS NOISE?
When the sound wave is non-periodic, irregular and very short duration, it produces
displeasing effect. Such a sound is known as noise.

6. CHARACTERISTICS OF SOUND
Soft surfaces, such as textiles, and batt insulation, tend to absorb sound waves, preventing
them from further motion.
Hard surfaces, such as ceramic tile, gypsum board, or wood, tend to reflect sound waves,
causing ‘echo’. Reverberation is the term used to describe sound waves that are reflected
off of surfaces.
Dense, massive, materials, such as concrete or brick, tend to transmit sound waves through
the material.
High frequency sound waves (think of a high whistle) are not capable of being transmitted
through massive, heavy, material.
 Low frequency sound waves (bass) are transmitted through massive materials.

7. REFLECTION OF SOUND
Sound wave also gets reflected as light waves do. Bouncing back of sound wave from the surface of
solid or liquid is called reflection of sound.

8. ABSORPTION
 When a sound wave strikes a surface, a part of its energy is absorbed by friction. This is known as absorption.
 It is measured in sabin.
 The sound generated in auditorium or hall is absorbed in 4 ways:
1. In the air
2. By the audience
3. In furniture and furnishing
4. At the boundary surfaces such as floors, walls, ceilings, etc.

9. SOUND INSULATION
Sound Insulation is the measure by which the transmission of sound/noise from inside to
outside or vice-versa or from one room to the other is prevented.
The function of a sound absorbent material is to absorb and thus reduce the sound reflected
from a surface.

10. SOUND INSULATING MATERIAL
Non-porous materials
Porous rigid materials
Non-rigid porous materials

11. WALL INSULATION
1. Rigid homogeneous walls
2. Partition walls of porous materials
3. Double wall partition
4. Cavity wall construction

12. 1. RIGID HOMOGENEOUS WALLS
A rigid wall consists of stone, brick or concrete masonry construction, well plastered on one
or both sides.
Sound insulation depends upon their per unit area.
Sound insulation increases with the increase in the thickness of the wall.

13. 2. PARTITION WALLS OF POROUS MATERIALS
The porous materials may be rigid or non-rigid.
Rigid porous materials increases insulation 10% than the non-porous materials.
However, non-porous material offer very low sound insulations.

14. 3. DOUBLE WALL PARTITION
Consists of plaster board or fibre boards
or plaster on laths on both the faces with
sound absorbing blanket in between.

15. 4. CAVITY WALL CONSTRUCTION
The two faces of the wall may be fixed with celotex or other insulating board.
The width of cavity should be at least 5 cm and the two wall leaves should be tied by use of
only light butterfly wall ties.

16. FLOORS AND CEILINGS INSULATION
Use of resilient materials on floors
Concrete floor floating construction
Timber floor floating construction
Timber floor with suspended ceiling and air space
skirting

17. 1. USE OF RESILIENT MATERIALS ON FLOOR
By covering floor with resilient material such as
insulation board, linoleum, cork, asphalt etc.
This provision helps to damp the impact noises.
An insulation of 5 to 10 dB over the base concrete
floor may be obtained with such a material.

18. 2. CONCRETE FLOOR FLOATING CONSTRUCTION

19. 3. TIMBER FLOOR FLOATING CONSTRUCTION

20. 4. TIMBER FLOOR WITH SUSPENDED CEILING AND
AIR SPACE
air borne & structure borne
use metal hanger to support ceiling of RCC slab

21. 5. SKIRTING
The larger the contact area it provides between
the floor area the walls, the lower would be the
insulation.
An air gap or resilient material between the
skirting and the floor is provided.

22. NOISE CONTROL IN RESIDENTIAL BUILDING
Double wall construction
Construction of false ceiling
Properly gasketing
Less opening
Airgap as sound insulation
Use sound insulation material
Construct floating floor
Use personal protective device

23. THANK YOU