herman kwok advanced acoustics project
TRANSCRIPT
BSCI 9060 – Advanced Acoustics Project
Measure of Sound Pressure at Building Envelope
Herman Kwok
Introduction
Wikipedia:
Green Roof - a roof of a building that is partially or completely covered with vegetation and a growing medium
Purpose - absorbing rainwater, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures and mitigate the heat island effect.
…and Sound Attenuation
Green Roof
2 types of Green Roof
Intensive roofs - thicker and can support a wider variety of plants such as shrubs and even trees
Extensive roofs - light layer of vegetation, low-growing plants such as Sedum Species
Proposal
Noise Attenuation across Green Roofs
Collect Sound Pressure Level measurements along green roofs
Acoustical Façade Load
Identify Relationships and Patterns
Location
Great Northern Way Campus
BCIT Green Roof Research Facility
BCIT Green Roof Research Facility
BCIT Green Roof Research Facility
1065 sq.ft.
3 different sections of flat roofing with identical area
2 of them are green
Centre section is a typical flat roof with no vegetation, aka reference roof
Green roof on the east side named GR1 has 75mm (3") growing medium
GR2 on the west side has 150 mm (6")
Roofing assembly is fitted with weather poles, thermal couples, heat flux transducers, and soil moisture metres.
GR1 East Side 75mm Medium
GR2 West Side 150mm Medium
Reference Roof
Results
150mm medium had the greatest attenuation in the low frequency range (16hz to 200hz)
75mm medium had the greatest attenuation in the High Frequency range (250hz to 8000hz)
Weaknesses & Error Factors
Neighboring warehouse boom box was present
Large brick warehouse diffracted a lot of the noise generated by the omni-directional speaker
West side contained a non-vegetated slope and a concrete wall
Larger area of experimental roofs may be needed
Traffic noise from the Great Northern Way
Outside temperature fluctuated from around 12 degree Celsius to 3 degree Celsius
Reference
[1] Renterghem T. V. & Botteldooren D. (2008). Green Roofs for Quietness. Ghent University, Department of Information Technology, Acoustics group, Belgium
[2] Connelly, M. & Hodgson, M. (2008). Sound Transmission Loss of Extensive Green Roofs. Living Architecture Monitor, Fall 2008, Pg. 24-29.
[3] Button, D. (June 2008). Green Roof Solves Loud Noise Problem for Tasmania University Union. Jaws Architects
[4] http://commons.bcit.ca/greenroof/research/infrastructure-research/bcit-green-roof-research-facility-vancouver/
[5] http://commons.bcit.ca/greenroof/faq/what-is-the-bcit-centre-for-architectural-ecology/
[6] http://www.greenroofs.com/projects/pview.php?id=731
THANK YOU