Introduction
1.1 This section provides guidance on an appropriate programme of sound insulation testing for a sample of properties, under Regulation 41 of the Building Regulations and Regulation 20(1) and (5) of the Approved Inspectors Regulations.
1.2 Sound insulation testing to demonstrate compliance with Requirement E1 should be carried out on site as part of the construction process, and in this Approved Document it is referred to as pre-completion testing. Under Regulation 41 and Regulation 20(1) and (5), the duty of ensuring that appropriate sound insulation testing is carried out falls on the person carrying out the building work, who is also responsible for the cost of the testing. Therefore, the guidance in this section is addressed in the first place to persons carrying out the work (and to testing bodies employed by them). However, it is also addressed to building control bodies, as the Secretary of State expects building control bodies to determine, for each relevant development, the properties selected for testing.
1.3 Testing should be carried out for:
a. purpose built dwelling-houses and flats;
b. dwelling-houses and flats formed by material change of use;
c. purpose built rooms for residential purposes;
d. rooms for residential purposes formed by material change of use.
1.4 The normal programme of testing is described in paragraphs 1.29 to 1.31.
1.5 The testing procedure formally approved by the Secretary of State is described in Annex B: Procedures for sound insulation testing.
1.6 The performance standards that should be demonstrated by pre-completion testing are set out in Section 0: Performance - Tables 1a and 1b. The sound insulation values in these tables have a built-in allowance for measurement uncertainty, so if any test shows one of these values not to have been achieved by any margin, the test has been failed.
1.7 The person carrying out the building work should ensure that the guidance on construction given in this Approved Document, or in another suitable source, is followed properly to minimise the chances of a failed test. Where additional guidance is required, specialist advice on the building design should be sought at an early stage.
1.8 Testing should not be carried out between living spaces and: corridors, stairwells or hallways.
1.9 Tests should be carried out between rooms or spaces that share a common area of separating wall or separating floor.
1.10 Tests should be carried out once the dwelling-houses, flats or rooms for residential purposes either side of a separating element are essentially complete, except for decoration. Impact sound insulation tests should be carried out without a soft covering (e.g. carpet, foam backed vinyl) on the floor. For exceptions and further information on floor coverings and testing see Annex B: paragraphs B2.13 and B2.14.
Grouping
1.11 The results of tests only apply to the particular constructions tested but are indicative of the performance of others of the same type in the same development. Therefore, in order for meaningful inferences to be made from tests, it is essential that developments are considered as a number of notional groups, with the same construction type within each group.
1.12 Grouping should be carried out according to the following criteria. Dwelling-houses (including bungalows), flats and rooms for residential purposes should be considered as three separate groups. In addition, if significant differences in construction type occur within any of these groups, sub-groups should be established accordingly.
1.13 The following guidance should allow suitable sub-grouping in most circumstances.
Sub-grouping for new buildings
1.14 For dwelling-houses (including bungalows), sub-grouping should be by type of separating wall. For flats, sub-grouping should be by type of separating floor and type of separating wall. Rooms for residential purposes should be grouped using similar principles.
1.15 The construction of flanking elements (e.g. walls, floors, cavities) and their junctions are also important. Where there are significant differences between flanking details, further sub-grouping will be necessary.
1.16 Sub-grouping may not be necessary for dwelling-houses, flats and rooms for residential purposes that have the same separating wall and/or separating floor construction, with the same associated flanking construction(s), and where the room dimensions and layouts are broadly similar.
1.17 Some dwelling-houses, flats or rooms for residential purposes may be considered to have unfavourable features: an example could be flats with large areas of flanking wall without a window at the gable end. It would be inappropriate for these to be included as part of a group and these should form their own sub-group(s).
Sub-grouping for material change of use
1.18 The same principles as for new buildings apply, but in practice significant differences are more likely to occur between separating wall and/or separating floor constructions as well as the associated flanking construction(s) in a development. More sub-groups may therefore be required, and group sizes may be smaller. Building control bodies should exercise judgement when setting up sub-groups.
Sets of tests in dwelling-houses (including bungalows)
1.19 Normally, one set of tests should comprise two individual sound insulation tests (two airborne tests):
• A test of insulation against airborne sound between one pair of rooms (where possible suitable for use as living rooms) on opposite sides of the separating wall.
• A test of insulation against airborne sound between another pair of rooms (where possible suitable for use as bedrooms) on opposite sides of the separating wall.
Sets of tests in flats with separating floors but without separating walls
1.20 Normally, one set of tests should comprise four individual sound insulation tests (two airborne tests, two impact tests):
• Tests of insulation against both airborne and impact sound between one pair of rooms (where possible suitable for use as living rooms) on opposite sides of the separating floor.
• Tests of insulation against both airborne and impact sound between another pair of rooms (where possible suitable for use as bedrooms) on opposite sides of the separating floor.
Sets of tests in flats with a separating floor and a separating wall
1.21 Normally, one set of tests should comprise six individual sound insulation tests (four airborne tests, two impact tests):
• A test of insulation against airborne sound between one pair of rooms (where possible suitable for use as living rooms) on opposite sides of the separating wall.
• A test of insulation against airborne sound between another pair of rooms (where possible suitable for use as bedrooms) on opposite sides of the separating wall.
• Tests of insulation against both airborne and impact sound between one pair of rooms (where possible suitable for use as living rooms) on opposite sides of the separating floor.
• Tests of insulation against both airborne and impact sound between another pair of rooms (where possible suitable for use as bedrooms) on opposite sides of the separating floor.
1.22 To conduct a full set of tests, access to at least three flats will be required.
Types of rooms for testing
1.23 It is preferable that each set of tests contains individual tests in bedrooms and living rooms.
1.24 Where pairs of rooms on either side of the separating element are different (e.g. a bedroom and a study, a living room and a bedroom), at least one of the rooms in one of the pairs should be a bedroom and at least one of the rooms in the other pair should be a living room.
1.25 Where the layout has only one pair of rooms on opposite sides of the entire area of separating wall or floor between two dwelling-houses, flats or rooms for residential purposes then the number of airborne and impact sound insulation tests set out in paragraphs 1.19 to 1.21 may be reduced accordingly.
1.26 The approved procedure described in Annex B includes requirements relating to rooms.
Sets of tests in rooms for residential purposes
1.27 To conduct a set of tests, the sound insulation between the main rooms should be measured according to the principles set out in this section for new buildings and material change of use, but adapting them to suit the circumstances.
Properties sold before fitting out
1.28 Some properties, for example loft apartments, may be sold before being fitted out with internal walls and other fixtures and fittings. Measurements of sound insulation should be made between the available spaces, according to the principles set out in this section. Steps should be taken to ensure that fitting out will not adversely affect the sound insulation. Some guidance on internal wall and floor constructions is given in Section 5. Junction details between these internal walls and floors and separating walls and floors are described in Sections 2 and 3.
Normal programme of testing
1.29 Building control bodies should consult with developers on likely completion times on site, and ask for one set of tests to be carried out between the first dwelling-houses, flats or rooms for residential purposes scheduled for completion and/or sale in each group or sub-group. This applies regardless of the intended size of the group or sub-group. Therefore if a site comprises only one pair of dwelling-houses, flats or rooms for residential purposes, they should be tested.
1.30 As further properties on a development become ready for testing, building control bodies should indicate at what point(s) they wish any further set(s) of tests to be conducted. Assuming no tests are failed, building control bodies should stipulate at least one set of tests for every ten dwelling-houses, flats or rooms for residential purposes in a group or sub-group.
1.31 Testing should be conducted more frequently at the beginning of a series of completions than towards the end, to allow any potential problems to be addressed at an early stage. However, on large developments testing should be carried out over a substantial part of the construction period.
Action following a failed set of tests
1.32 A set of tests is failed if any of its individual tests of airborne or impact sound insulation do not show sound insulation values equal to or better than those set out in Section 0: Performance - Tables 1a and 1b.
1.33 In the event of a failed set of tests, appropriate remedial treatment should be applied to the rooms that failed the test.
1.34 A failed set of tests raises questions over the sound insulation between other rooms sharing the same separating element in the dwelling-houses, flats or rooms for residential purposes in which the tests were conducted. The developer should demonstrate to the building control body's satisfaction that these rooms meet the performance standards. Normally this would be done by (a) additional testing, and/or (b) applying the appropriate remedial treatment to the other rooms and/or (c) demonstrating that the cause of failure does not occur in other rooms.
1.35 A failed set of tests raises questions over properties between which tests have not been carried out. The developer should demonstrate to the building control body's satisfaction that such properties meet the performance standards. Once a dwelling-house, flat or room for residential purposes is occupied, any action affecting it should be a matter for local negotiation.
1.36 After a failed set of tests, the rate of testing should be increased until the building control body is satisfied that the problem has been solved.
Remedial treatment
1.37 Appropriate remedial treatment should be applied following a failed set of tests. It is essential that remedial work is appropriate to the cause of failure. Guidance is available in BRE Information Paper IP 14/02.
1.38 Where the cause of failure is attributed to the construction of the separating and/or associated flanking elements, other rooms that have not been tested may also fail to meet the performance standards. Therefore, remedial treatment may be needed in rooms other than those in which the tests were conducted.
1.39 Where remedial treatment has been applied, the building control body should be satisfied with its efficacy. Normally this will be assessed through additional sound insulation testing.
Material change of use
1.40 As stated in Section 0, in the case of some historic buildings undergoing a material change of use, it may not always be practical to achieve the sound insulation values set out in Section 0: Performance - Tables 1a and 1b. However, in such cases building control bodies should be satisfied that everything reasonable has been done to improve the sound insulation. Tests should be carried out, and the results displayed as indicated in Section 0, paragraph 0.7.
Approved manner of recording pre-completion testing results
1.41 In order to satisfy the requirements of paragraph (3)(a) of Regulation 41 or Regulation 20(1) and (5), the test report of a set of tests (where set of tests has the meaning given in paragraphs 19–1.21 and 1.27) must contain at least the following information, in the order below:
Address of building.
Type(s) of Use the definitions in Regulation 2: dwelling-house, flat, room for residential purposes. State if the building is a historic building (see definition in the section on Requirements of this Approved Document).
Date(s) of testing.
Organisation carrying out testing, including:
a. name and address;
b. third party accreditation number (e.g. UKAS or European equivalent);
c. name(s) of person(s) in charge of test;
d. name(s) of client(s).
- A statement (preferably in a table) giving the following information:
a. the rooms used for each test within the set of tests;
b. the measured single-number quantity (DnT,w + Ctr for airborne sound insulation and L’nT,w for impact sound insulation) for each test within the set of tests;
c. the sound insulation values that should be achieved according to the values set out in Section 0: Performance – Table 1a or 1b; and
d. an entry stating ‘Pass’ or ‘Fail’ for each test within the set of tests according to the sound insulation values set out in Section 0: Performance – Table 1a or 1b.
- Brief details of test, including:
a. equipment;
b. a statement that the test procedures in Annex B have been followed. If the procedure could not be followed exactly then the exceptions should be described and reasons given;
c. source and receiver room volumes (including a statement on which rooms were used as source rooms);
d. results of tests shown in tabular and graphical form for third octave bands according to the relevant part of the BS EN ISO 140 series and BS EN ISO 717 series, including:
i. single-number quantities and the spectrum adaptation terms;
ii. DnT and L’nTdata from which the single- number quantities are calculated.
