BCIT Thesis and other Required Graduate Degree Works | BCIT Institutional Repository

BCIT Thesis and other Required Graduate Degree Works

The absorption and scattering characteristics of interior living walls
Installation of interior living walls is increasing rapidly due to their beauty, biophilic design and their potential contribution to indoor environmental quality. However, there is little understanding of the specific effect they have on the acoustics of a room. To advance the state of practice, this interdisciplinary study explores the acoustical characteristics of interior living walls to determine how they can be used to positively benefit room acoustic by reducing excess noise and reverberation. Specifically, the objective of the research is to measure the acoustical characteristics of the interior living wall in order to determine their absorption coefficient, scattering coefficient, and the parameters that most significantly impact these coefficients. First, a series of measurements are carried out in a reverberation chamber to examine random-incidence absorption by considering parameters such as carrier type, moisture content, vegetation type, and substrate. In addition, both absorption and scattering coefficients are examined by considering various vegetation types and coverage. The findings from empirical measurements facilitate a sensitivity analysis, with the use of the commercial software Odeon, of the absorption and scattering coefficients. Next, the empirical absorption and scattering coefficients are used on a model, developed in the commercial software Odeon, to see the effect of interior living walls on room acoustics. The aim of this study is to evaluate the application of interior living walls as a sustainable and acoustically beneficial material for buildings of any kind., Acoustical characteristics of interior living walls, Sound absorption coefficient, Sound scattering coefficient, Odeon software, Room acoustics, Living wall
Experimental investigation of living architecture design tools to attenuate rooftop noise
The aim of this research is to investigate the viability of designing urban rooftop soundscapes. The prerequisite is to reduce the sound propagation from road traffic by introducing living architectural rooftops with various components of sound attenuating technologies. The final goal is to turn unused rooftop space into a livable urban green space, where soundscape is balanced, and sound energy is reduced to the limits recommended by the World Health Organization (WHO). The first part of this research is to identify the potential of living architectural technologies to attenuate noise from road traffic. More than 33 measurements are performed of living architecture design tools, such as green roofs, berms at edge, living wall barriers and overhangs, to investigate the behavior of sound attenuation in an anechoic chamber and in ODEON, a computer simulation software. The second part of this research is to use the findings on the proposed design tools for an architectural case study, a flat-roof five-storey building located on East Hastings Street. The use of a combination of green roof, berm, overhang, guard and living wall can reduced urban traffic noise from 70 dBA on the roof to 55 dBA, creating additional acoustically healthy habitable space in the urban environment.
Sound transmission of wood frame split insulated rainscreen cavity wall assemblies
Exterior building envelope walls with rainscreen cavities are now required by British Columbia building codes. The introduction of the rainscreen cavity and optional external thermal insulation can alter sound transmission loss and consequently affect indoor sound levels in single and multi-family wood-frame housing. In this study, 57 exterior wall assemblies were built and acoustically evaluated using a hybrid sound intensity technique. The variables investigated were cladding material (vinyl, fibre cement board, and stucco), exterior insulation (mineral wool and XPS), exterior insulation thickness (1 ½" and 3"), cladding attachment type (resilient and non-resilient), and rainscreen cavity width (3/8" and 1"). The sound transmission class of the tested wall assemblies ranged from 37 to 52; the outdoor-indoor transmission class rating ranged from 26 to 37. Results indicated that the selection and the combination of the material layers were fundamental to sound transmission loss performance. Cladding material and cladding attachments influenced sound transmission and resulted in a broad range of overall performance. The split insulated rainscreen cavity wall assemblies presented higher transmission loss than single insulation walls, provided that the exterior insulation had sound absorbing properties. The best performing wall assemblies generally have high mass cladding, resilient cladding attachment, and 3" mineral wool exterior insulation (in addition to the interior cavity insulation). Given the research outcomes, in denser and noisier urban areas, a building envelope professional has additional options to design an exterior rainscreen cavity wall to meet thermal performance and acoustical criteria for exterior sound levels in wood frame buildings.