Green roofs in Melbourne - potential and practice

In Melbourne, green roofs are increasingly being included in the new and retrofitted buildings that claim to be ‘sustainable’ or ‘green’. This enthusiasm follows overseas experience where a variety of benefits have been recorded; these include a reduction in heating and cooling loads. This benefit is of particular importance because of the urgent need to reduce the greenhouse gas emissions associated with air conditioning. What is the potential for such savings and to what extent are some of the existing green roofs likely to achieve these benefits? This paper begins with a review of the overseas experience to reduce conditioning loads, particularly cooling, in temperate climates. Some observations on the potential and practice of green roofs in Melbourne is then presented. The results of measurements of plant canopy, soil and hard surface temperatures on two green roofs in the Melbourne Central Business District are discussed and future on-going work is outlined.

On the acoustic performance of a precast panel system made from environmentally sustainable concrete : application in sports hall buildings

The use of green building materials and products promotes conservation of non-renewable resources and help reduce associated environmental impacts. This article reports the acoustical performance of a precast panel system made largely from concrete waste material. Two major applications for such panels that are being investigated currently include walls and claddings to industrial and commercial buildings and sound barriers for urban freeways. In this study, the application of the concrete panels for optimizing reverberation time (RT) in sports halls is tested using numerical simulations. As an innovative approach, additional layers are added to the precast panels to improve their appearance. The absorption coefficients of the concrete panel improved significantly with the architectural finish. The material can be tuned according to the required peak frequency. The architectural finish helped reduce the RT for frequencies above 500 Hz. Its application to different types of ceilings revealed that the RT of curved ceiling reduced up to 40% compared to flat and hybrid ceiling. A comparison of wall and ceiling modifications in small, medium and large sports halls showed that medium-sized halls have better acoustical performance compared with small and large halls with ceiling as well as wall treatment.

Representation of multiculturalism in urban green spaces : a review of immigrants' experiences in Australia

Rapid population influx due to migration in Australia has produced diverse cultural landscapes, which become visible in cities as physical forms, settings and symbols produced by different ethnic communities. Scholars have argued that people moving away from the country of their birth, whether this be a necessary migration, labour mobility or voluntary migration, results in a difficult process of resettlement for families and individuals. To provide a cohesive multicultural society for all citizens, it is essential to understand how immigrants perceive their new environments and how they make connections in a new land in the process of cultural renewal. While the policy of ‘multiculturalism’ has had a rocky road since the optimistic 1970s, a drive through many suburbs in Australian cities shows buildings, festivals and communal gatherings of people that express and refer to diverse cultural backgrounds. Urban green spaces, ranging from private home gardens to public parks and botanical gardens, play an important role in the life of immigrants. Besides psychological and the restorative effects of urban green spaces, these spaces are public places that provide opportunities for recreation, social gatherings, and the celebration of collective cultural values and events such as festivals for many communities. This study aims to raise awareness of ethnicity as an important issue in park settings and spaces. It investigates the interrelationship between these cultural practices in the urban park environment, in relation to ethnic and cultural identity and physical settings. The concept of transculturalism – reinventing a new common culture as a result of migration to a new place – can help the analysis of the affects and the perception of urban green spaces. The paper will review different experiences of immigrants in relation to the use and perception of urban green spaces, developing alternative perspectives about the Australian landscapes.

The effect of green roofs on pedestrian level air temperature

Man made alterations have resulted in higher air temperatures in cities, compared to their surrounding rural areas. There are many attempts to modify the urban design elements to ameliorate urban heat island effect. One among them is the concept of green roofs. There is a potential to incorporate vegetation to the large roof area of the buildings. Several studies investigated the effect of micro and macro scale implementation of green roofs. Most of these studies examined the impact of green roofs on the air temperature variation at the roof level, whereas studies are lacking on the effect of green roof at the pedestrian level. Therefore, this study aims to explore the impact of green roofs on the air temperature at pedestrian level, in the central business district (CBD), using Melbourne as a case study. A generic layout of Melbourne's CBD is modelled using ENVI-met 3.1 BETA 4. A number of different scenarios with different green roof coverages and building heights are examined. It was found that green roofs did not have significant impact on the temperatures at pedestrian level.