5.2 Noise reduction between rooms
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Changing lifestyles has altered the way rooms are used in dwellings. Bedrooms are more often used as areas where people spend time watching television, playing computer games and listening to music. Shouting from room to room, running up and down stairs, using noisy appliances and banging doors, can all be heard throughout a dwelling and can create unwanted noise. At night, any noise made when generally there is little background noise, is often perceived as excessive.
Although noise within a dwelling, can be more easily controlled than noise from outwith the dwelling itself, this can still be a nuisance. The increase in noise level from speech and music within dwellings may indirectly lead to anxiety and stress.
Conversions - in the case of conversions as specified in regulation 4, the building as converted shall meet the requirements of this standard (regulation 12, schedule 6).
Internal walls are normally built off the structural floor. A door located in such a wall provides a path for sound to bypass a wall under test. On-site sound testing of internal walls and intermediate floors cannot be relied upon due to excessive flanking sound transmission through doors. For this reason a laboratory test is used. A laboratory test result is termed dB Rw (see 5.0.4).
As disturbance to occupants can occur from other areas within the dwelling, the level of sound heard should be reduced in the rooms in which people may sleep. Therefore it is the internal walls between apartments, an apartment and an internal space where noise is likely to occur, that should achieve the sound performance level below. An internal wall between an en-suite bathroom and the apartment it serves need not have sound insulation.
The design performance levels for internal walls and intermediate floors covered by this standard should achieve minimum airborne sound insulation levels indicated in the following table:
Table 5.5. Table 5.5 Design performance levels
| Design performance | Minimum airborne insulation level |
|---|---|
| Internal walls | 40 dB Rw |
| Intermediate floors | 43 dB Rw |
The design performance levels in clause 5.2.1 can be achieved by using the Generic Internal Constructions available on the BSD website http://www.scotland.gov.uk/topics/built-environment/building/building-standards. Alternatively, product manufacturers may have solutions that will achieve the design performance level.
Improving the sound insulation over parts of an intermediate floor only above or below apartments is not reasonably practicable and could lead to expensive remedial measures if an area is missed or if future alteration work is carried out. It is therefore recommended that sound insulation should be provided across the entire area of each intermediate floor in a dwelling if there is an apartment located directly or below the floor.
The design performance levels in clause 5.2.1 can be achieved by using the Generic Internal Constructions available on the BSD website http://www.scotland.gov.uk/topics/built-environment/building/building-standards. Alternatively, product manufacturers may have solutions that will achieve the design performance level.
Although setting impact sound insulation design levels for intermediate floors is not reasonably practicable, insulation against impact noise can be improved by adding a soft covering such as a carpet or foam-backed vinyl. However a carpet or foam-backed vinyl is a floor covering and should not be included as part of the construction used to achieve the design levels in clause 5.2.1.
Many of the existing wall and floor constructions within a traditional building, will be constructed from materials generally not still in use, for example lathe and plaster. In such cases the sound insulation level will not be known therefore, it is not reasonably practicable for the existing walls or floors to meet the performance levels in clause 5.2.1.