Ourimbah Road, Mosman

40–56 Ourimbah Road, Mosman

Octave Acoustics was engaged by First Quadrant Properties to provide acoustic consultancy services for a State Significant Development Application for 63 unit, 8 level multi-residential building on a medium-density residential site in Mosman.

The site is located adjacent to Ourimbah Road, a classified road carrying significant traffic volumes, presenting road traffic noise as a primary acoustic design challenge. Octave Acoustics conducted a nine-day unattended noise monitoring program to establish background noise levels and characterise the road traffic noise environment, forming the basis for assessment under the NSW Road Noise Policy and Transport and Infrastructure SEPP 2021.

A three-dimensional CadnaA noise model was developed and calibrated against monitoring results to calculate façade noise loads and derive minimum acoustic performance requirements for glazing and wall systems across all levels of the building. Glazing performance requirements ranged from Rw 28 to Rw 39, with provision of acoustically attenuated ventilation specified where necessary to allow windows to remain closed while satisfying BCA ventilation requirements.

Mechanical plant noise was assessed against the NSW EPA Noise Policy for Industry, with representative plant, including domestic condenser units, carpark exhaust and hot water heat pumps, incorporated into the noise model. Compliance was demonstrated with standard attenuation measures including acoustic plant screening, condenser quiet modes and acoustically treated plant rooms.

Construction noise and vibration impacts were assessed across three works phases, demolition, bulk earthworks and construction. Calculated impacts were benchmarked against Interim Construction Noise Guideline management levels and AS2187/DIN 4150 building damage criteria. The proximity of established residential receivers on all four boundaries resulted in a detailed construction impacts mitigation and management framework being incorporated into the SSDA documentation.

The project is proceeding under the Housing SEPP infill affordable housing provisions as a State Significant Development, with the acoustic assessment prepared to address the Secretary’s Environmental Assessment Requirements.