ACOUSTIC BENEFITS OF VERTICAL GREENERY

Abstract

As the result of industrial revolution, rapid urbanization has caused bad impacts onto the environment. The consequences of the urbanization have become more serious in last 20 years, such as urban heat island effect, solid waste, ravaged ecosystem, etc. The recognition of these impacts made people start thinking about sustainability for buildings as buildings account for a large amount of land use, energy and water consumption, and air and atmosphere alteration. One way to achieve sustainability is “build green”. Two interesting and relatively new concepts of green building are rooftop garden (green roof) and vertical greenery. The latter one was developed after the proved success of the former one. Both of them seem to offer the most ideal solution in mitigating rising temperatures in vastly urbanized areas without compromising on precious land space. Besides other environmental benefits, green roof is proved to provide a shielding effect against the noise pollution. Noise pollution refers to the environmental noise or community noise rather than the indoor noise issue. In other words, green roof reduces the acoustic facade load from the environmental noise sources. However, acoustic benefit of vertical greenery remains debatable. Therefore, some experiments were carried out to investigate the acoustic characteristic of the vertical greenery. The statistics suggested that the vertical greenery also performed as a barrier interrupting the noise though it is not quite effective. The noise reduction was believed to come from the growing media and the plants. The relationship between the quantity of growing media and plants with ability to reduce noise level of vertical greenery was unclear. On the other hand, vertical greenery exhibited a good absorption capability. Its absorption rate was considerably high compared with other common building materials. And the rate was observed to be proportional with the quantity of the plants. However, further study of noise reduction would be carried out with outdoor noise source and indoor receiver.