Annex B: Procedures for sound insulation testing

  1. B1 Introduction
    1. B2 Field measurement of sound insulation of separating walls and floors for the purposes of Regulation 41 and Regulation 20(1) and (5)
      1. B3 Laboratory measurements
        1. B4 Information to be included in test reports

          B1 Introduction

          B1.1 Section B.2 of this Annex describes the sound insulation testing procedure approved by the Secretary of State for the purposes of Regulation 41(2)(a) of the Building Regulations and Regulation 20(1) of the Approved Inspectors Regulations. The approved procedure is that set out in Section B.2 and the Standards referred to in that Section.

          B1.2 Section B.3 of this Annex provides guidance on laboratory testing in connection with achieving compliance with Requirement E2 in Schedule  1 to the Building Regulations, and in connection with evaluation of components to be used in constructions subject to Requirement E1.

          B1.3 Section B.4 of this Annex gives guidance on test reports.

          B1.4 The person carrying out the building work should arrange for sound insulation testing to be carried out by a test body with appropriate third party accreditation. Test bodies conducting testing should preferably have UKAS accreditation (or a European equivalent) for field measurements. The ODPM also regards members of the ANC Registration Scheme as suitably qualified to carry out pre-completion testing. The measurement instrumentation used should have a valid, traceable certificate of calibration, and should have been tested within the past two years.

          B2 Field measurement of sound insulation of separating walls and floors for the purposes of Regulation 41 and Regulation 20(1) and (5)

          Introduction

          B2.1 Sound insulation testing for the purposes of Regulation 41 of the Building Regulations and Regulation 20(1) and (5) of the Approved Inspectors Regulations 2010, must be done in accordance with: BS EN ISO 140-4:1998; BS EN ISO 140- 7:1998; BS EN ISO 717-1:1997; BS EN ISO 717-2:1997; BS EN 20354:1993. When calculating sound insulation test results, no rounding should occur in any calculation until required by the relevant Standards, the BS EN ISO 140 series and the BS EN ISO 717 series.

          Airborne sound insulation of a separating wall or floor

          B2.2 The airborne sound insulation of a separating wall or floor should be measured in accordance with BS EN ISO 140-4:1998. All measurements and calculations should be carried out using one-third octave frequency bands. Performance should be rated in terms of the weighted standardised level difference, DnT,w, and spectrum adaptation term, Ctr, in accordance with BS EN ISO 717-1:1997.

          Measurements using a single sound source

          B2.3 For each source position, the average sound pressure level in the source and receiving rooms is measured in one-third octave bands using either fixed microphone positions (and averaging these values on an energy basis) or a moving microphone.

          B2.4 For the source room measurements, the difference between the average sound pressure levels in adjacent one-third octave bands should be no more than 6dB. If this condition is not met, the source spectrum should be adjusted and the source room measurement repeated. If the condition is met, the average sound pressure level in the receiving room, and hence a level difference, should be determined.

          B2.5 It is essential that all measurements made in the source and receiving rooms to determine a level difference should be made without moving the sound source or changing the output level of the sound source, once its spectrum has been correctly adjusted (where necessary).

          B2.6   The sound source should now be  moved to the next position in the source room and the above procedure repeated to determine another level difference. At least two positions should be used for the source. The level differences obtained from each source position should be arithmetically averaged to determine the level difference, D as defined in BS EN ISO 140-4:1998.

          Measurements using multiple sound sources operating simultaneously

          B2.7 For multiple sound sources operating simultaneously, the average sound pressure level in the source and receiving rooms is measured in one-third octave bands using either fixed microphone positions (and averaging these values on an energy basis) or a moving microphone.

          B2.8 For the source room measurements, the difference between the average sound pressure levels in adjacent one-third octave bands should be no more than 6dB. If this condition is not met, the source spectrum should be adjusted and the source room measurement repeated. If the condition is met, determine the average level in the receiving room, and hence the level difference, D as defined in BS EN ISO 140-4:1998.

          Impact sound transmission of a separating floor

          B2.9 The impact sound transmission of a separating floor should be measured in accordance with BS EN ISO 140-7:1998. All measurements and calculations should be carried out using one-third-octave frequency bands. Performance should be rated in terms of the weighted standardised impact sound pressure level, L’nT,w in accordance with BS EN ISO 717-2:1997.

          Measurement of reverberation time

          B2.10 BS EN ISO 140-4:1998 and BS EN ISO 140-7:1998 refer to the ISO 354 (BS EN 20354:1993) method for measuring reverberation time. However, for the approved procedure, the guidance in BS EN ISO 140-7:1998 relating to the source and microphone positions, and the number of decay measurements required, should be followed.

          Room requirements

          B2.11 Section 1 gives guidance on the room types that should be used for testing. These rooms should have volumes of at least 25m³. If this is not possible then the volumes of the rooms used for testing should be reported.

          Tests between rooms

          B2.12 Tests should be conducted in completed but unfurnished rooms or available spaces in the case of properties sold before fitting out; see Section 1.

          B2.13 Impact sound insulation tests should be conducted on a floor without a soft covering (e.g. carpet, foam backed vinyl) except in the case of (a) separating floor type 1, as described in this Approved Document, or (b) a concrete structural floor base which has a soft covering as an integral part of the floor.

          B2.14 If a soft covering has been installed on any other type of floor, it should be taken up. If that is not possible, at least half of the floor should be exposed and the tapping machine should be placed only on the exposed part of the  floor.

          B2.15 When measuring airborne sound insulation between a pair of rooms of unequal volume, the sound source should be in the larger room.

          B2.16 Doors and windows should be closed.

          B2.17 Kitchen units, cupboards etc. on all walls should have their doors open and be unfilled.

          Measurement precision

          B2.18 Sound pressure levels should be measured to 0.1dB precision.

          B2.19 Reverberation times should be measured to 0.01s precision.

          Measurements using a moving microphone

          B2.20 At least two positions should be used.

          B2.21 For measurements of reverberation time, discrete positions should be used rather than a moving microphone

          B3 Laboratory measurements

          Introduction

          B3.1 Pre-completion testing for the purposes of Regulation 41 and Regulation 20(1) and (5) involves field testing on separating walls and floors (see Section 1 and Annex B: B2). However, there are applications for laboratory tests to determine the performance of: floor coverings; floating floors; wall ties; resilient layers; internal walls and floors; and flanking laboratory tests to indicate the performance of novel  constructions.

          B3.2 When calculating sound insulation test results, no rounding should occur in any calculation until required by the relevant Standards, i.e. the BS EN ISO 140 series and the BS EN ISO 717 series.

          Tests on floor coverings and floating floors

          B3.3 Floor coverings and floating floors should be tested in accordance with BS EN ISO 140-8:1998 and rated in accordance with BS EN ISO 717-2:1997. The test floor should have a thickness of 140mm.

          B3.4 It should be noted that text has been omitted from BS EN ISO 140-8:1998. For the purposes of this Approved Document, Section 6.2.1 of BS EN ISO 140-8:1998 should be disregarded, and Section 5.3.3 of BS EN ISO 140-7:1998, respectively, referred to instead.

          B3.5 BS EN ISO 140-8:1998 refers to the ISO 354 (BS EN 20354:1993) method for measuring reverberation time, but the guidance in BS EN ISO 140-8:1998 relating to the source and microphone positions, and the number of decay measurements required, should be followed.

          B3.6 When assessing category II test specimens (as defined in BS EN ISO 140-8:1998) for use with separating floor type 2, the performance value (DLw) should be achieved when the floating floor is both loaded and unloaded. The loaded measurements should use a uniformly distributed load of 20–25kg/m² with at least one weight per square metre of the flooring area, as described in BS EN ISO 140-8:1998.

          Dynamic stiffness of resilient layers

          B3.7 Dynamic stiffness of resilient layers should be measured in accordance with BS EN 29052-1:1992. The test method using sinusoidal signals should be used. No pre-compression should be applied to the test specimens before the measurements.

          Dynamic stiffness of wall ties

          B3.8 Dynamic stiffness of wall ties should be measured in accordance with BRE Information Paper IP 3/01.

          Airborne sound insulation of internal wall and floor elements

          B3.9 The airborne sound insulation of internal wall or floor elements in a laboratory should be measured in accordance with BS EN ISO 140- 3:1995, and the performance rated in accordance with BS EN ISO 717-1:1997 to determine the weighted sound reduction index, Rw.

          Measurements in a flanking laboratory

          B3.10 Tests of sound transmission in a flanking laboratory include both direct and flanking  paths, and are a useful means of assessing the likely field performance of novel  constructions.

          B3.11 It is not possible to demonstrate compliance with Requirement E1 using test results from a flanking laboratory.

          Flanking laboratory: design

          B3.12 Construction details of a suitable laboratory can be obtained from the Acoustics Centre, BRE, Garston, Watford WD25 9XX.

          Note: A CEN standard for the laboratory measurement of flanking transmission between adjoining rooms is currently under development.

          Flanking laboratory: indicative airborne sound insulation values

          B3.13 When a test construction has airborne sound insulation of at least 49dB DnT,w  + Ctr when measured in a flanking laboratory using the procedure given in Annex B: B2, this can be taken as indicative that the same  construction (i.e. identical in all significant details) may achieve at least 45dB DnT,w  + Ctr  when built in the field. See paragraph B3.11.

          Flanking laboratory: indicative impact sound insulation values

          B3.14 When a test construction has impact sound insulation no more than 58dB L’nT,w  when measured in a flanking laboratory using the procedure given in Annex B: B2, this can be taken as indicative that the same construction (i.e. identical in all significant details) may achieve no more than 62dB L’nT,w when built in the field. See paragraph B3.11.

          B4 Information to be included in test reports

          Field test reports

          B4.1 Paragraph 1.41 of this Approved Document sets out the manner of recording the results of testing done for the purposes of Regulation 41 or Regulation 20(1) and (5), approved by the Secretary of State under those Regulations.

          Although not required, it may be useful to have a description of the building including:

          1. sketches showing the layout and dimensions of rooms tested;
          2. description of separating walls, external walls, separating floors, and internal walls and floors including details of materials used for their construction and finishes;
          3. mass per unit area in kg/m² of separating walls, external walls, separating floors, and internal walls and floors;
          4. dimensions of any step and/or stagger between rooms tested;
          5. dimensions and position of any windows or doors in external walls.

          Laboratory test reports for internal walls and floors

          B4.2 Test reports should include the following information.

          1. Organisation conducting test, including:

          • name and address;
          • third party accreditation number (e.g. UKAS or European equivalent);
          • Name(s) of person(s) in charge of test.

          2. Name(s) of client(s).

          3. Date of test.

          4. Brief details of test, including:

          • equipment;
          • test procedures.

          5. Full details of the construction under test and the mounting conditions.

          6. Results of test shown in tabular and graphical form for one-third octave bands according to the relevant part of the BS EN ISO 140 series and BS EN ISO 717 series, including:

          • single-number quantity and the spectrum adaptation terms;
          • data from which the single-number quantity is calculated.