For Siting Rooms
Where the window of bed-rooms and living rooms face a main traffic route or a railway, they should be not less than 30 m to 45 m from its near edge and should be more where possible. Where the windows face at right angles to the direction of the noise, or away from it, the distance may be reduced to about 23 m to 30 m. in the case of local roads the above distances may be reduced to 15 m and 11 m respectively. Trees also reduce sound to some extent.
For Walls
Sound transmission through partitions can be reduced by the following method:
A massive and rigid construction that does not have openings for pipes or ventilators. Sound is transmitted through holes and cracks, and space left due to badly fitting doors and windows.
A hard reflecting surface on the outside of the wall.
An air gap to prevent continuity of structure (hollow walls).
A layer of insulating material. An air space is generally better than a filling material.
A non-homogeneous structure containing inert cells.
A sound absorbent surface facing the other room such as; fiber boards, hair felt, mineral wool or slag wool. Fiber boards and porous surfaces should not be painted or varnished.
For Floors
Sound transmission through floors can be reduced by:
A “floating floor” which is isolated from the walls by inserting a thin strip of felt or some other similar insulation between the skirting and the floor boards. A layer consisting of not less than 5 cm of concrete is poured in-situ upon a resilient quilt overlying the main supporting structure (bottom concrete under the floors).
Provision of sound insulating materials between the floor make an effective deadening pad. Wood, cork, rubber or asphaltic combinations effectively deaden sound.
A massive and rigid construction.
A hollow floor construction.
Insulated and suspended ceiling.
It is possible to reduce the harshness of floor noise by resilient converting such as carpets, cork or linoleum if the materials are reasonably thick.
To prevent echoes the back wall behind the audience should be highly absorbent of sound, and there should be an absorbent area on the side walls near the platform or stage end to prevent lateral echoes.
Sound Insulating Materials
Compressed straw or reeds slabs
Cork slabs
Slag wool
Sponge rubber
Wood shavings
Felt
Bitumen
Asbestos
Breeze bricks
A layer 12 to 25 mm thickness is usually sufficient. Increased spacing of glass in double window is particularly useful in improving the insulation at low frequencies, which are important in traffic noise.
