Page 124 - GRIHA Manual Volume IV - Introduction to National Rating System
P. 124
Building planning and construction 115
Figure 10 Example of aesthetic treatment of sound barrier. External barrier wall with recesses and vegetation to
break monotony.
Strategies to control indoor noise levels
For reducing indoor noise levels, the following steps should be implemented.
# Reduce the hard paved surfaces around the building in order to minimize ground reflections of
sound. Develop maximum area around the building as softscape or covered in plantations.
# Buildings should be located at a distance of at least 30 m from a road with heavy traffic (80–90
dB) (NBC 2005).
# Walls or partitions should have a Sound Reduction Index of 40 dB or higher (NBC 2005).
# In general offices, the reverberation time should not exceed 1 sec (NBC 2005).
There is a direct relation between the sound insulation and mass of materials. Typical sound
reduction indices for a few materials are given in the table below.
Table 1 Sound insulation of imperforate sheet materials
Material Surface mass Typical weighted Sound Reduction Index, R w
kg/m
dB
2
3 mm glass sheet 7.0 26
18 mm wood particle board 8.0 27
1 mm steel sheet 11.0 29
12 mm wood ibre insulation board 4.0 24
13 mm mineral ibre board 4.0 24
50 mm wood-wool screeded one side 35.0 33
Source National Building Code(2005), Part 8, Section 4
Figure 10 Example of aesthetic treatment of sound barrier. External barrier wall with recesses and vegetation to
break monotony.
Strategies to control indoor noise levels
For reducing indoor noise levels, the following steps should be implemented.
# Reduce the hard paved surfaces around the building in order to minimize ground reflections of
sound. Develop maximum area around the building as softscape or covered in plantations.
# Buildings should be located at a distance of at least 30 m from a road with heavy traffic (80–90
dB) (NBC 2005).
# Walls or partitions should have a Sound Reduction Index of 40 dB or higher (NBC 2005).
# In general offices, the reverberation time should not exceed 1 sec (NBC 2005).
There is a direct relation between the sound insulation and mass of materials. Typical sound
reduction indices for a few materials are given in the table below.
Table 1 Sound insulation of imperforate sheet materials
Material Surface mass Typical weighted Sound Reduction Index, R w
kg/m
dB
2
3 mm glass sheet 7.0 26
18 mm wood particle board 8.0 27
1 mm steel sheet 11.0 29
12 mm wood ibre insulation board 4.0 24
13 mm mineral ibre board 4.0 24
50 mm wood-wool screeded one side 35.0 33
Source National Building Code(2005), Part 8, Section 4
