Introduction
This Appendix describes the sound insulation testing procedure in accordance with Technical Guidance Document E and provides guidance on sound insulation test reporting.
Sound insulation testing should be carried out by a competent person, possessing sufficient training, experience and knowledge in the measurement of sound insulation in buildings.
Field measurement of sound insulation
Field measurement of sound insulation of separating walls and floors
The measurement instrumentation used, should have a valid, traceable certificate of calibration, and should have been verified within the past two years. The sound calibrator should be independently verified at intervals not exceeding one year.
As stated in Technical Guidance Document E all compliance testing should be conducted by an accredited laboratory or other body with the appropriate authorisation to perform the relevant tests and calibrations.
Sound insulation testing should be carried out in accordance with the following documents:
I.S. EN ISO 16283-1: 2014;
I.S. EN ISO 16283-2: 2018
I.S. EN ISO 717-1: 2013;
I.S. EN ISO 717-2: 2013;
I.S. EN ISO 3382-2: 2008.
When calculating sound insulation test results, no rounding should occur in any calculation until required by the relevant standards listed above.
Airborne sound insulation testing of a separating wall or floor
As indicated in Technical Guidance Document E the airborne sound insulation testing of a separating wall or floor should be measured in accordance with the default procedure described in I.S. EN ISO 16283-1, in the frequency range 100 Hz to 3150 Hz. The low-frequency measurement procedure should not be used.
All measurements and calculations should be carried out using one-third octave frequency bands. Performance should be rated in terms of the weighted standardized level difference, DnT,w in accordance with I.S. EN ISO 717-1.
Measurements using a single sound source
An omni-directional sound source should be used which meets the directivity requirements of Annex A of I.S. EN ISO 16283-1. 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.
For the source room measurements, the difference between the average sound pressure levels in the adjacent one-third octave bands should be no more than 8 dB. 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.
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 achieved. The sound source should then be moved to the next position in the source room and the above procedure repeated to determine another level difference. At least two positions, at a minimum 1.4 metres apart, should be used with each source position also varied in height by at least 0.7 metres.
The standardised level differences, in one-third octave bands, obtained from each source position shall be inverse-energy averaged to determine the level difference, DnT according to equation 6 of I.S. EN ISO 16283-1.
Measurements using multiple sound sources operating simultaneously
Omni-directional sound sources should be used which meets the directivity requirements of Annex A of I.S. EN ISO 16283-1. The sound sources should be driven by separate and uncorrelated signals and adjusted so that each sound source is of a similar level.
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.
For the source room measurements, the difference between the average sound pressure levels in the adjacent one-third octave bands should be no more than 8 dB. 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 sound pressure level in the receiving room, and hence the level difference, D as defined in I.S. EN ISO 16283-1.
Impact sound transmission of a separating floor
A standard tapping machine should be used in accordance with I.S. EN ISO 16283-2. The impact sound transmission of a separating floor should be measured in accordance with the procedure described in I I.S. EN ISO 16283-2, in the frequency range 100 Hz to 3150 Hz.
The average sound pressure level in the receiving room is measured in one-third octave bands using either fixed microphone positions (and averaging these values on an energy basis) or a moving microphone.
The standardised impact sound pressure levels, in one-third octave bands, obtained from each tapping machine position shall be energy averaged to determine the standardised impact sound pressure level L'nTin accordance with equation 7 of I.S. EN ISO 16283-2.
Performance should be rated in terms of the weighted standardised impact sound pressure level difference, L'nT,w in accordance with I.S. EN ISO 717-2.
Measurement of reverberation time
The reverberation time in the receiving rooms should be measured using the uninterrupted noise method or the integrated impulse response method as described in I.S. EN ISO 3382-2. At least two source positions, with a total of six decays should be used.
Room requirements
Test rooms should be restricted to living rooms and bedrooms where possible. Kitchens and dining rooms may be considered where this is not possible.
Test rooms should have volumes of at least 25m3. If this is not possible then the volumes of the rooms used for testing should be noted in the test report.
In apartment buildings, the dwellings chosen for test should be representative of the various dwelling layouts.
Tests between rooms
Tests should be conducted in completed but unfurnished rooms as indicated in Technical Guidance Document E.
When tests are being carried out doors and windows (including trickle vents) should be closed; kitchen units, cupboards etc., on all walls should have their doors open and be unfilled.
When measuring airborne sound insulation between a pair of rooms of unequal volume, the sound source should be in the larger room.
For separating walls, two individual tests should be carried out on any one separating wall, providing there are two pairs of valid rooms either side of the wall (e.g. in a pair of dwelling houses with living room pairs on the ground floor and bedroom pairs on the first floor), two tests can be carried out, one at ground floor and one at first floor. For separating floors, two individual tests may be carried out on any one separating floor, providing there are two pairs of valid rooms between the floor (e.g. in a pair of flats with living rooms stacked one directly above another and bedrooms stacked one directly above another) then two tests can be carried out, living room pairs and bedroom pairs.
For separating floors, the airborne and impact tests should be treated as a set and must be carried out on the same separating floor. Therefore, the minimum number of tests must include both an airborne sound insulation test and an impact sound transmission test (e.g. 2 airborne and 2 impact tests should be carried out to make up 2 test floor constructions).
Impact sound insulation tests should be conducted on a floor without a soft covering (a resilient layer is not a soft covering) e.g. carpet, foam backed vinyl. If a soft covering has been installed, 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.
In Floor Type 1 the tapping machine should be placed on the fixed resilient layer.
Measurement precision
As detailed in Technical Guidance Document E measurement precision should be as follows:
Sound pressure levels should be measured to 0.1 dB precision.
Reverberation times should be measured to 0.01s precision.
Measurements using a moving microphone
At least two positions relating to the sound source should be used.
For measurements of reverberation time, discrete positions should be used rather than a moving microphone.
Information for inclusion in test reports
In accordance with the requirements of Technical Guidance Document E test reports should contain at least the following information, in the order listed below:
1. Address(es) of buildings subject to testing;
2. Type(s) of dwelling, i.e. dwelling house, apartment, etc;
3. With reference to Table 3A (or Table 3B, as appropriate), the addresses of the other dwellings on the site for which this report is also applicable.
4. Date(s) when testing was conducted;
5. Organisation/ person carrying out testing, including:
Name and address,
Proof of competency, and
Name(s) of client(s).
6. A statement (preferably in a table) giving the following information:
Rooms used for each test within the 'set of tests'. NOTE: State volume of room if less than 25 m3,
The measured single-number quantity (DnT,w for airborne sound insulation and L'nT,w for impact sound insulation) for each individual test within a 'set of tests',
Description of separating walls, external walls, separating floors, and internal walls and floors including details of materials used in their construction and finishes. NOTE: Where certified constructions types (see paragraph 2.3) are employed the certificate number and issuing body should also be provided.
The sound insulation values that should be achieved according to the values set out in Table 1 of Technical Guidance Document E.
7. Brief details of test, including:
equipment used,
a statement that the test procedures in Appendix A have been followed,
results of tests shown in tabular and graphical form for third octave bands according to the relevant standards referred to in A.2, including:
- single number quantities and the spectrum adaptation terms, and
- the DnT and L'nT data from which the single quantities are calculated.
8. Although not specifically required, it may be useful to have a description of the building including:
sketches showing the layout and dimensions of the rooms tested;
mass per unit area in kg/m2 of separating walls and separating floors;
dimensions of any step or stagger between rooms tested;
dimensions and position of any windows or doors in external walls.
