Diagram 5-1: Internal wall type A
5.18 Internal wall type B: Timber or metal frames with plasterboard linings on each side of frame and absorbent material (see Diagram 5-2)
Diagram 5-2: Internal wall type B
5.19 Internal wall type C: Concrete block wall, plaster or plasterboard finish on both sides (see Diagram 5-3)
Diagram 5-3: Internal wall type C
5.20 Internal wall type D: Aircrete block wall, plaster or plasterboard finish on both sides (see Diagram 5-4)
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Diagram 5-4: Internal wall type D
5.21 Internal floor type A: Concrete planks (see Diagram 5-5)
Note: Insulation against impact sounds can be improved by adding a soft covering (e.g. carpet).
Diagram 5-5: Internal floor type A
5.22 Internal floor type B: Concrete beams with infilling blocks, bonded screed and ceiling (see Diagram 5-6)
Note: Insulation against impact sounds can be improved by adding a soft covering (e.g. carpet).
Diagram 5-6: Internal floor type B
5.23 Internal floor type C: Timber or metal joist, with wood based board and plasterboard ceiling, and absorbent material (see Diagram 5-7)
Note: Insulation against impact sounds can be improved by adding a soft covering (e.g. carpet).
Diagram 5-7: Internal floor type C
Note: Electrical cables give off heat when in use and special precautions may be required when they are covered by thermally insulating materials. See BRE BR 262, Thermal Insulation: avoiding risks, section 2.3.
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6.1 Rooms for residential purposes are defined in Regulation 2 of the Building Regulations 2000 (as amended). This definition is reproduced after the Requirements in this Approved Document.
6.2 This Section gives examples of wall and floor types, which, if built correctly, should meet the performance standards set out in Section 0: Performance - Table 1 b.
6.3 The guidance in this section is not exhaustive and other designs, materials or products may be used to achieve the performance standards set out in Section 0: Performance - Table 1 a. Advice should be sought from the manufacturer or other appropriate source.
6.4 Of the separating walls described in Section 2 the following types are most suitable for use in new buildings containing rooms for residential purposes:
Wall type 1. Solid masonry
Note: Plasterboard may be used as an alternative wall finish, provided a sheet of minimum mass per unit area 10 kg/m2 is used on each room face.
Wall type 3. Masonry between independent panels
Note: Wall types 2 and 4 can be used provided that care is taken to maintain isolation between the leaves. Specialist advice may be needed.
6.5 Separating walls described in 6.4 should be used between rooms for residential purposes and corridors in order to control flanking transmission and to provide the required sound insulation between the dwelling and the corridor. However, it is likely that the sound insulation will be reduced by the presence of a door.
6.6 Ensure any door has good perimeter sealing (including the threshold where practical) and a minimum mass per unit area of 25 kg/m2. Alternatively, use a doorset with a minimum sound reduction index of 29dB Rw (measured in the laboratory according to BS EN ISO 140- 3:1995 and rated according to BS EN ISO 717- 1:1997). The door should also satisfy the Requirements of Building Regulation Part B - Fire safety.
6.7 Noisy parts of the building (e.g. function rooms or bars), should preferably have a lobby, double door or high performance doorset to contain the noise. Where this is not possible, nearby rooms for residential purposes should have similar protection. However, do ensure that there are doors that are suitable for disabled access, see Building Regulation Part M - Access and facilities for disabled people.
6.8 Of the separating floors described in Section 3 the following types are most suitable for use in new buildings containing rooms for residential purposes:
Floor type 1. Concrete base with soft covering
Note: Floor types 2 and 3 can be used provided that floating floors and ceilings are not continuous between rooms for residential purposes. Specialist advice may be needed.
6.9 It may be that an existing wall, floor or stair in a building that is to undergo a material change of use will achieve the performance standards set out in Section 0: Performance - Table 1 b without the need for remedial work. This would be the case if the construction was similar (including flanking constructions) to one of the constructions in paragraphs 6.4 and 6.8 (e.g. for solid walls and floors the mass requirement should be within 15% of the mass per unit area of a construction listed in the relevant section).
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6.10 For situations where it cannot be shown that the existing construction will achieve the performance standards set out in Section 0: Performance - Table 1 b, Section 4 describes wall, floor and stair treatments to improve the level of sound insulation in dwellings formed by material change of use. These treatments may be used in buildings containing rooms for residential purposes. Specialist advice may be needed.
6.11 In order for the construction to be fully effective, care should be taken to detail correctly the junctions between the separating wall and other elements, such as floors, roofs, external walls and internal walls.
6.12 In the case of new buildings containing rooms for residential purposes, refer to the guidance in Sections 2 and 3 which describes the junction and flanking details for each of the new build separating wall and floor types.
6.13 When rooms for residential purposes are formed by material change of use, refer to the notes and diagrams in Section 4 that describe the junction and flanking details for the wall and floor treatments.
6.14 In the case of the junction between a solid masonry separating wall type 1 and the ceiling void and roof space, the solid wall need not be continuous to the underside of the structural floor or roof provided that:
The ceiling joists and plasterboard sheets should not be continuous between rooms for residential purposes. See Diagram 6-1.
6.15 This ceiling void and roof space detail can only be used where the Requirements of Building Regulation Part B - Fire safety can also be satisfied. The Requirements of Building Regulation Part L - Conservation of fuel and power should also be satisfied.
Diagram 6-1: Ceiling void and roof space (only applicable to rooms for residential purposes)
6.16 Internal noise levels are affected by room layout, building services and sound insulation.
6.17 The layout of rooms should be considered at the design stage to avoid placing noise sensitive rooms next to rooms in which noise is generated.
6.18 Additional guidance is provided in BS 8233:1999 Sound Insulation and Noise Reduction for Buildings - Code of Practice and Sound Control for Homes. See Annex D: References.
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7.1 This Section describes how to determine the amount of additional absorption to be used in corridors, hallways, stairwells and entrance halls that give access to flats and rooms for residential purposes.
7.2 For the purposes of this Section, a corridor or hallway is a space for which the ratio of the longest to the shortest floor dimension is greater than three.
7.3 For the purposes of this Section, an entrance hall is a space for which the ratio of the longest to the shortest floor dimension is three or less.
7.4 When an entrance hall, corridor, hallway or stairwell opens directly into another of these spaces, the guidance should be followed for each space individually.
7.5 The choice of absorptive material should meet the Requirements of Building Regulation Part B - Fire safety.
7.6 Two methods are described to satisfy Requirement E3, Method A and Method B.
7.7 Method A: Cover a specified area with an absorber of an appropriate class that has been rated according to BS EN ISO 11654:1997 Acoustics – Sound absorbers for use in buildings – Rating of sound absorption.
7.8 Method B: Determine the minimum amount of absorptive material using a calculation procedure in octave bands. Method B is intended only for corridors, hallways and entrance halls as it is not well suited to stairwells.
7.9 Where additional guidance is required, specialist advice should be sought at an early stage.
7.10 For entrance halls, corridors or hallways, cover an area equal to or greater than the floor area, with a Class C absorber or better. It will normally be convenient to cover the ceiling area with the additional absorption.
7.11 For stairwells or a stair enclosure, calculate the combined area of the stair treads, the upper surface of the intermediate landings, the upper surface of the landings (excluding ground floor) and the ceiling area on the top floor. Either, cover at least an area equal to this calculated area with a Class D absorber, or cover an area equal to at least 50 % of this calculated area with a Class C absorber or better. The absorptive material should be equally distributed between all floor levels. It will normally be convenient to cover the underside of intermediate landings, the underside of the other landings, and the ceiling area on the top floor.
7.12 Method A can generally be satisfied by the use of proprietary acoustic ceilings. However, the absorptive material can be applied to any surface that faces into the space.
7.13 In comparison with Method A, Method B takes account of the existing absorption provided by all surfaces. In some cases, Method B should allow greater flexibility in meeting Requirement E3 and require less additional absorption than Method A.
7.14 For an absorptive material of surface area, S in m2, and sound absorption coefficient, a, the absorption area A is equal to the product of S and .
7.15 The total absorption area, AT, in square metres is defined as the hypothetical area of a totally absorbing surface, which if it were the only absorbing element in the space would give the same reverberation time as the space under consideration.
7.16 For n surfaces in a space, the total absorption area, AT, can be found using the following equation.
AT = 1S1 + 2S2 +...+nSn
7.17 For entrance halls, provide a minimum of 0.20 m2 total absorption area per cubic metre of the volume. The additional absorptive material should be distributed over the available surfaces.
7.18 For corridors or hallways, provide a minimum of 0.25 m2 total absorption area per cubic metre of the volume. The additional absorptive material should be distributed over one or more of the surfaces.
7.19 Absorption areas should be calculated for each octave band. Requirement E3 will be satisfied when the appropriate amount of absorption area is provided for each octave band between 250 Hz and 4000 Hz inclusively.
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7.20 Absorption coefficient data (to two decimal places) should be taken from the following:
7.21 In Method B, each calculation step is to be rounded to two decimal places.
Table 7.1: Absorption coefficient data for common materials in buildings
| Material | Sound absorption coefficient, a in octave frequency bands (Hz) | ||||
| 250 | 500 | 1000 | 2000 | 4000 | |
| Fair-faced concrete or plastered masonry | 0.01 | 0.01 | 0.02 | 0.02 | 0.03 |
| Fair-faced brick | 0.02 | 0.03 | 0.04 | 0.05 | 0.07 |
| Painted concrete block | 0.05 | 0.06 | 0.07 | 0.09 | 0.08 |
| Windows, glass façade | 0.08 | 0.05 | 0.04 | 0.03 | 0.02 |
| Doors (timber) | 0.10 | 0.08 | 0.08 | 0.08 | 0.08 |
| Glazed tile/marble | 0.01 | 0.01 | 0.01 | 0.02 | 0.02 |
| Hard floor coverings (e.g. lino, parquet) on concrete floor | 0.03 | 0.04 | 0.05 | 0.05 | 0.06 |
| Soft floor coverings (e.g. carpet) on concrete floor | 0.03 | 0.06 | 0.15 | 0.30 | 0.40 |
| Suspended plaster or plasterboard ceiling (with large airspace behind) | 0.15 | 0.10 | 0.05 | 0.05 | 0.05 |
7.22 Evidence that Requirement E3 has been satisfied should be presented, for example on a drawing or in a report, which should include:
7.23 Example: Entrance hall
The entrance hall has dimensions 3.0 m (width) x 4.0 m (length) x 2.5 m (height). The concrete floor is covered with carpet, the walls are painted concrete blocks and there are four timber doors (1.0 m x 2.4 m).
To satisfy Requirement E3, either use:
7.24 Method B is described in steps 1 to 8 in Table 7.2. In this example; the designer considers that covering the entire ceiling is a convenient way to provide the additional absorption. The aim of the calculation is to determine the absorption coefficient, aceiling, needed for the entire ceiling.
7.25 In this example, the absorption coefficients from Method B indicate that a Class D absorber could be used to cover the ceiling. This can be compared against the slightly higher absorption requirement of Method A, which would have used a Class C absorber or better to cover the ceiling.
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