Sound Absorption and Scattering Properties of Living walls: Applications to Room Acoustics

Authors

  • Maureen Connelly British Columbia Institute of Technology
  • Daver Bolbolan
  • Mahsa Akbarnejad
  • Sepideh Daneshpanah

Abstract

This work presents the research framework and the investigations of the acoustical characteristics of interior living walls and their impact on room acoustics. The overall goal is to determine how living walls can be used to positively benefit room acoustics by reducing reverberation and ambient noise, and affect speech intelligibility by creating sonic subzones within rooms.

A method of evaluation at one-third scale was developed to measure the scattering effects of substrates and plant species (Bolbolan). A series of measurement were carried out to quantify the absorption of living walls with consideration of the parameters of carrier type, substrate, moisture content and plant species variants and to determine which parameters most significantly impact the absorption and scattering of living walls (Akbarnejad). The research on the verification of effect of interior living walls on room acoustics includes field measurement experiments of permutations of living walls installed in a 132 m2 theater designed for interactive workshops (Daneshpanah); classroom acoustic criteria such as background A-weighted noise, noise criteria (NC) curves, reverberation time, and speech intelligibility are measured and modelled for a 60 m2 seminar classroom with varying living wall installations.

Measurement determined that the scattering coefficient of living wall substrate meets the ISO 17497-1 criteria for the turning table base plate. This allowed six living wall plant species, English Ivy, Fern, Golden Pothos, Pilea, Spider plant, Ficus pumila, to be further evaluated in substrate. The function of ‘leaf area index X mass’ was found to be more relevant than plant foliage characteristics (height, stem diameter, mass, leaf thickness, leaf length, leaf area) in predicting absorption; overall coverage is relevant to high-frequency scattering. Living walls reduced reverberation time and may affect speech intelligibility in close proximity to the living wall as measured and modelled in the classroom application.

Author Biography

Maureen Connelly, British Columbia Institute of Technology

Dr. Maureen Connelly PhD| Director, Faculty | Centre for Architectural Ecology | BCIT School of Construction and the EnvironmentCurrent research focus is on architectural acoustics with a specific focus on living architecture.  Research subjects she currently leads includes: urban acoustics, outdoor sound propagation, building envelop noise control and sound transmission, acoustical building materials, quantification of the acoustical capacity of living architecture to reduce sound transmission through buildings, reduction of noise build up in urban areas, and enhancement of personal and shared soundscapes.  Current course delivery includes BSCI 9060 Advanced Acoustics (graduate level course) and BSCI 7200 Acoustical Science and Ecology.  Maureen is currently leading an initiative on soundscape and acoustical integration into whole building performance.

Published

2016-08-16

How to Cite

1.
Connelly M, Bolbolan D, Akbarnejad M, Daneshpanah S. Sound Absorption and Scattering Properties of Living walls: Applications to Room Acoustics. Canadian Acoustics [Internet]. 2016 Aug. 16 [cited 2022 Dec. 8];44(3). Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2965

Issue

Section

Proceedings of the Acoustics Week in Canada