Regulatory Impact Assessment: Signed 16 November 2002

Appendix B: Significant changes associated with Requirement E1 Protection against sound from adjoining dwellings or buildings etc.

'Rooms for residential purposes' (includes hotels, boarding houses, hostels, student accommodation, nurses' homes and elderly persons' homes) are now covered by Requirement.
New guidance on rooms for residential purposes in Approved Document E - Section 6.
Vertical transmission of impact sound now covered by Requirement where a dwelling or a room for residential purposes is above another part of the same building that is not part of the dwelling above.

Bathroom walls now covered by Requirement where they are adjacent to other parts of the same building.

Introduction of an explicit (minimum) performance standard to replace the current need to infer the meaning of 'reasonable sound insulation' from the performance of the constructions described in the current Approved Document E.
New performance standard increases the required level of airborne sound insulation for separating floors and brings it into line with that for separating walls.
New performance standard set at a higher level than current implicit target values.
New performance standard for airborne sound insulation adopts a new rating method that takes better account of the transmission of low frequency sounds.

Introduction of pre-completion testing regime to apply to new dwellings, material change of use and rooms for residential purposes.
Encouragement of more frequent pre-completion testing for material change of use.
Introduction of 'test and declare' system for material change of use.
Explicit mention of need for attention to sound insulation requirements between adjoining residential and non-residential uses.

Technical changes to guidance on separating and flanking constructions in the Approved Document so that constructions remaining in the Document are likely to meet the performance standard and removal of those constructions that are less likely to meet the performance standard:

e.g. reduced use of plasterboard finish on masonry separating walls included in Section 2 of Approved Document E;
e.g. lightweight blocks not included in Section 3 of Approved Document E for use in flanking walls in flats; and
e.g. concrete beam and block separating floors not included in Section 3 of Approved Document E.
e.g. additional aerated concrete block construction included in Section 2 (Wall Type 2.4) in order to increase the number of constructions that will also satisfy the revised Approved Document L.

Revisions and restructuring to reflect the importance of flanking sound transmission.
Restructuring so that constructions are ranked in order of performance (based on current available knowledge) within each separating wall and floor type.
Alternative ceiling specifications given for separating floor type 2, again ranked in order of performance.
Change from current generic descriptions of constructions and construction elements to performance standards, which encourage development of proprietary products, wherever current knowledge allows:

e.g. 'butterfly tie' now any wall tie meeting dynamic stiffness requirements;
e.g. use of proprietary floating floors (with floor type 2) provided they meet laboratory measurement requirements; and
e.g. plasterboard now described by mass per unit area rather than thickness.

Updating to reflect changes in relevant Standards. In particular, the performance standards set using indicators from BS EN ISO 717-1:1997 i.e. D_nT,w + C_tr
Supplementary guidance on acoustic measurement standards to clarify ambiguities in current Standards - Approved Document E - Annex C.
'Similar Construction Method For New Building' replaced by pre-completion testing.
'Test Chamber Evaluation For New Construction' replaced by pre-completion testing.
'Field and Laboratory Tests For Conversions' replaced by pre-completion testing.