MCU21.0193-Att 1 Acoustic Report

5. Discussion
5.1.     Acoustic Flooring
During the weight drop tests it was observed that significant structural vibration was being
produced through the walls of the neighbouring Davidson Hair and BCC Cinema Noosa
tenancies. Vibration through the floor was also noticed in Cinema 1 at BCC Cinema Noosa,
located above and to the west the gym. The issues are primarily related to the lack of stiffness
and inherent flexibility of the floor structure. These problems with the slab are inherent to the
structure and would require a significant amount of work to improve given the large size of
the building.

To achieve the minimum noise and vibration impact to neighbouring tenancies, the most
effective solution for the gym floor would be a double layer of Regupol 4080. This system
would not make all activities inaudible at the neighbouring tenancies, and there is still a
potential for adverse impacts. Refer to Section 5.3 for methods to further reduce vibrational
impacts to tenancies.


5.2.     Airborne Noise Transmission and Speakers
The current intertenancy wall between the gym and the cinema foyer consists of a temporary
wall with a single sheet of 10mm plywood. The airborne noise transmission test conducted
during the site visit and shown in Table 4 was not an accurate representation as to the wall
construction will change during the fit-out. The builder has informed us they will likely be
installing 6.38lam glazing throughout the intertenancy wall. Therefore, the estimated impacts
below are based on the intertenancy wall being constructed with 6.38lam glazing, acoustic
seals and 13mm plasterboard. It is recommended to have an additional test done after the
gym is fully constructed to ensure an accurate noise level is implemented within the gym.

With the hairdresser's current intertenancy wall system and the cinema's proposed wall system
it is recommended that to minimise noise impacts to the neighbouring tenancies, a noise level
of approximately 70dBA is achieved within the gym, including music and speech from patrons.
If a higher noise level is desired, the wall system between the gym and hairdresser must be
improved. An improvement in the rating would allow an identical increase in the allowable
noise levels inside, e.g., 10 rating points would increase the allowable noise levels inside by
10dB. For a satisfactory noise level, it is encouraged that the client proactively discusses
impacts with the neighbours.

To reduce impacts further, it is also recommended that any installed speakers are to face away
from adjoining tenancies, not located on intertenancy walls and/or should be isolated from the
structure using a spring isolation system with a minimum static deflection of 25mm.




Acoustic Works 2/8 Castlemaine St, P.O. Box 1271 Coorparoo DC QLD 4151 Phone (07) 3393 2222   Page 7