Building Regulations: Technical Standards

17. Independent ceiling Absorbent blanket of 25 mm unfaced mineral fibre, density 12-36 kg/m3, draped over 45 mm thick joists supported independently of the floor. Ceiling of two layers of plasterboard with joints staggered, total thickness 30 mm. Keep ceiling 150 mm away from the underside of the floor base.

Junctions for floor type 4 External wall or separating wall Mass of leaf must be 355 kg/m2 (including any plaster), both above and below the floor, on at least 3 sides. Leaf on fourth side must be at least 180 kg/m2. Use bearers on walls to support the edges of the ceiling and to block air paths. Seal the junction of ceiling and wall with tape or caulking. Internal wall If masonry, mass must be 180 kg/m2. No restriction if stud partition. Support and seal as for external walls. Floor penetrations Ducts or pipes penetrating the floor must be in an enclosure both above and below the floor. Either line the enclosure, or wrap the duct or pipe within the enclosure, with 25 mm unfaced mineral fibre. The material of the enclosure must have a mass of 15 kg/m2. Penetrations of a separating floor by ducts and pipes must have fire protection in accordance with Part D. Where permitted by Part F, a flue-pipe may penetrate the floor. The flue-pipe must be in a non-combustible enclosing duct with mineral fibre absorbent. Seal the junction of ceiling and enclosure with tape or caulking.

Performance standards and test procedures

Standards

18. A wall or floor will meet the requirements for sound insulation if the following values are achieved when the performance is tested after construction under the procedures set out in 19 to 29.

Airborne Sound

Minimum values of weighted standardised level difference
(DnT,w) as defined in BS EN ISO 717-1: 1997

Impact Sound

Maximum values of weighted standardised impact sound pressure level
(L'nT,w) as defined in BS EN ISO 717-2: 1997

Test procedures

19. For each wall or floor which requires to be tested take four sets of measurements, or as close to four as possible given the following restrictions -

a. for each set of measurements use a pair of rooms if possible;

b. use a pair consisting of a room and some other space only where necessary to make up the four sets;

c. use a pair consisting of spaces other than rooms only where no other measurement is possible; and

d. take only one set of measurements between each pair.

20. When measuring between a pair of rooms of unequal area, the sound source must be in the larger room.

21. When measuring between a room and some other space, the sound source must be in the other space.

22. Carry out the tests for airborne sound in accordance with BS EN ISO 140-4: 1998 and for impact sound in accordance with BS EN ISO 140-7: 1998. The tests are to be done in completed but unfurnished dwellings. Doors and windows must be closed. The tests will determine the standardised level differences (DnT) for airborne sound transmission and the standardised impact sound pressure levels (L'nT) for impact sound transmission.

23. For each set of measurements calculate the weighted standardised level difference (DnT,w) in accordance with BS EN ISO 717-1: 1997 or the weighted standardised impact sound pressure level (L'nT,w) in accordance with BS EN ISO 717-2: 1997.

24. The calculated value from each set of measurements must be no worse than that stated in the "Individual Value" column in point 18.

25. The mean of the four^? calculated values must be no worse than that stated in the "Mean Value" column in point 18.

  where only two or three sets of measurements have been possible the mean must still be reached, and where only one set is possible the value achieved must not be worse than the mean value.

26. In a building every wall or floor, or part of a wall or floor, which requires sound resistance and is of nominally identical construction, may be regarded as forming part of a single wall or floor e.g. in a block of flats a wall rising through several storeys may be regarded as a single wall, and floors over a whole storey may be regarded as a single floor, wherever the flat plans are nominally identical.

27. A wall which changes construction only in a roof space may be regarded as a single wall.

28. In any group of dwellings covered by one building warrant, walls and floors of nominally identical dwelling types which are similarly situated in regard to adjoining buildings may all be regarded as meeting the performance standard if the ones selected for test meet the standard.

29. Note that the test procedure described above is intended only to provide evidence that a particular wall or floor not built to a specified construction satisfies the performance standards set out in point 18.