5.2 Noise reduction between rooms
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In the past many noise complaints have came, from occupants of residential buildings, such as hotels, residential care buildings and student residences. In most cases, these tend to occur where there is noise transfer from communal areas, particularly when people return late, bang doors or talk too loudly, and to a lesser extent noise between rooms.
Although noise within a unit of residential accommodation can be controlled by the management to a certain extent, it is not possible to control all of the noise made from everyone and every source within the building. This increase in noise levels from speech and music within individual units can lead to anxiety and stress.
NHS regulations, SHTM 2045, provide guidance on designing for noise in hospitals and healthcare facilities.
The Scottish Prison Service produces guidance on the design requirements for places of lawful detention.
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.
As disturbance to occupants can occur from other areas within a residential building, the level of sound heard should be reduced in the rooms in which people may sleep. Therefore it is the internal walls between rooms, rooms intended for sleeping and an internal space where noise is likely to occur that should achieve the sound performance level. An internal wall between an en-suite bathroom and the room it serves need not have sound insulation.
The design performance levels for internal walls and intermediate floors covered by this standard should achieve a minimum airborne sound insulation level of 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 rooms that are intended for sleeping, 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 if there is a room that is intended for sleeping, located directly above 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 lath 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.
Doors in residential buildings that provide direct access from common areas to rooms intended for sleeping, such as hotel bedrooms create a weak point in the wall, acoustically. This allows unwelcome noise into the room. Noise can more readily pass through a lightweight door than a heavy door and, the weakest point for noise to enter will be through the gap between the door and the frame.
Rooms intended for sleeping should be separated by a door that will act as a sound barrier and reduce noise transference. Therefore, a door that provides direct access to a room intended to be used for sleeping should have an overall mass per unit area of at least 25 kg/m2.
The door should also be fitted with a perimeter seal, excluding the threshold, to minimise noise transmittance through the doorset. A compressible type of seal may be used, such as a rubber strip. Where the seal is of a type that combines a smoke and noise seal, the product literature should be consulted to confirm the seal will achieve the desired effect. The seal should not interfere with the closing mechanisms of a fire door and provide a positive seal between the door frame and the door.