ByLaw #46 (Hard flooring)
No proprietor shall install hard flooring without the written consent of the Body Corporate and that in granting the consent the body Corporate may impose the following conditions and any other reasonable conditions it deems necessary to manage floor impact noise so as to not unreasonably affect the acoustic amenity for lower occupied or adjacent areas;
1. Any installed hard floor surface is to provide a level of floor impact isolation of LnTw 55 (ref AAAC 3 Star – www.aaac.org.au) or better, between lower or adjacent occupied or residential areas (as per ISO 140 Part 7).
2. Prior to the installation of the floor surface, advice must be sought from a recognised acoustic consulting company with regard to suitable floor treatments to meet this level of isolation. This may include:
a. a preliminary floor impact isolation test to determine the isolation provided by the base floor slab under consideration.
b. testing on a sample of the isolation system to be used to confirm the final performance outcome.
The acoustic consulting company is to provide a written report providing their recommendations to achieve the required LnTw 55, and documenting the basis for providing these recommendations.
3. Upon completion of the works the floor shall be tested to ensure that the minimum impact isolation requirement has been met. This test must be carried out in accordance with the procedures defined in ISO Standard 140 Part 7 by a company experienced with and recognised for this type of work. A system will be accepted as being in compliance with the design criterion, if the performance level is not more than one (1) unit above the compliance level (not greater than LnTw 56). This tolerance is allowed as it is recognised that impact isolation levels can vary in different locations in the same building.
4. An impact isolation test certificate is to be submitted to the Body Corporate within ten (10) days of the test showing compliance with the defined limit.
5. Should the tested floor fail to meet the Body Corporates performance requirements, it is the responsibility of the Unit Owner to rectify the matter at their own cost.
Notes:
• The Body Corporate does not endorse or recommend any particular impact isolation product or system; or acoustic consulting company.
• The selected floor impact isolation system must be laid strictly in accordance with the suppliers recommended installation procedures.
• The installed hard floor surfaces must not touch the perimeter walls with there being a minimum 5mm gap between the walls and the hard floor surface. This gap is to be sealed with a resilient sealant.
• The LnTw 55 limit provides a “good” level of acoustic isolation and significantly exceeds the Queensland Building Code of Australia minimum floor impact isolation requirements.
• LnTw is a corrected noise level in the receiving space and a lower level indicates a higher level of performance.
• For further information on this matter, refer to the Association of Australian Acoustical Consultants Guideline “Acoustical Star ratings for Apartments and Townhouses” re www.aaac.org.au.
• Impact isolation testing requires access into the lower apartment for close to thirty (30) minutes. Such access needs to be arranged by the occupier of the apartment under consideration.
DEFINITIONS
Hard floor surfaces are tiles, stone, ceramic, timber, cork, vinyl or other floor surfaces that are inherently hard. Carpeted floors normally will significantly exceed the isolation requirements and do not need to be considered under this by-law.
ISO 140 “Acoustics – Measurement of sound insulation in buildings and of building elements – Part 7 Field measurements of impact sound insulation of floors”.
LnTw – L’nT,w – Weighted Standardised impact sound pressure level; a measurement of impact sound transmission between rooms. Lower values denote better performance. The single figure measure is derived by adapting a standard response curve to measured 1/3 octave band sound pressure levels. Measured results are adjusted based upon a reverberation tone of 0.5 sec in receiving room. Normally derived from a field test. This is a measure of the room noise levels when using a standardised tapping machine with a lower number representing a higher level of impact isolation.