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.

Solar Panel Modeling on Suitable Roofs at Colby

With the recent construction of Colby Green and the current plans for the construction of several new buildings, the total area for future development on campus has declined. The goal of this study was to illustrate existing campus development and to determine where future growth could occur. GIS was used in determining the different soil systems on campus, the current use of the land, and the boundaries of the Colby property. The project shows what potential obstacles the college will have in attempting to expand the campus and proposes where the best options are for construction.

Thermal comfort indices in individual shelters for dairy calves with different types of roofs

Dentre os materiais de construção utilizados nas instalações rurais, merecem destaque as coberturas, pois são grandes responsáveis pelo conforto térmico, influenciando no balanço térmico no interior das instalações. Este trabalho objetivou avaliar a influência das coberturas sobre a entalpia (H), Carga Térmica Radiante (CTR) e no Índice de Temperatura de Globo Negro e Umidade (ITGU), em abrigos individuais para bezerros leiteiros. O delineamento foi o inteiramente casualizado com três tratamentos: Z - telha de zinco; CA - telha de cimento amianto, e CAB - telha de cimento amianto pintada de branco na face superior. As médias foram comparadas pelo teste de Scott Knott, a 1% de probabilidade. Os resultados mostraram que não houve diferença estatística entre os tratamentos (P<0,01) e o ambiente externo, para a H. Para a CTR, houve diferença estatística entre todos os tratamentos, em que CAB demonstrou menor CTR, 489,28 W m-², seguido do tratamento CA, 506,72 W m-², e Z com maior valor de CTR, 523,55 W m-². Para o ITGU, observaram-se menores valores para CAB (76,8) e CA (77,4), diferindo-se, significativamente do Z, que obteve maior valor (81,6). As telhas com pintura branca em sua face superior promoveram menor CTR e menor ITGU, favorecendo o ambiente térmico da instalação.

Flat roofs renovation: a life cycle approach for environmental impact assessment and economic effectiveness

The high energy consumption caused by the building sector and the continuous growth and ageing of the existing housing stock show the importance of housing renovation to improve the quality of the environment. This research compares the environmental performance of flat roof systems (insulation, roofing membrane and covering layer) using Life Cycle Assessment (LCA). The aim is to give indications on how to improve the environmental performance of housing. This research uses a reference building located in the Netherlands and considers environmental impacts related to materials, energy consumption for heating and maintenance activities. It indicates impact scores for each material taking into account interconnections between the layers and between the different parts of the life cycle. It compares the environmental and economic performances of PV panels and of different materials and thermal resistance values for the insulation. These comparisons show that PV panels are convenient from an environmental and economic point of view. The same is true for the insulation layer, especially for materials as PIR (polyisocyanurate) and EPS (expanded polystyrene). It shows that energy consumption for heating causes a larger share of impact scores than production of the materials and maintenance activities. The insulation also causes larger impact scores comparing to roofing membrane and covering layer. The results show which materials are preferable for flat roof renovation and what causes the largest shares of impact. This gives indication to the roofers and to other stakeholders about how to reduce the environmental impact of the existing housing stock.

Runoff Water Quality and Pollutant Mass Loads From Extensive Green Roofs

Green roof mitigation of volume and peak flow-rate of stormwater runoff has been studied extensively. However, due to the common practice of green roof fertilization, there is the potential for introduction of nutrients into local bodies of water. Therefore, this study compares green roof runoff quality with the water quality of precipitation and runoff from a bare shingle roof. The runoff from a demonstration-scale extensive green roof was analyzed during the summer of 2011 for its effect on runoff volume and analyzed during eleven storm events in the fall and winter for concentrations of copper, cadmium, zinc, lead, nitrogen species, total nitrogen, total organic carbon, sulfate, orthophosphate, and other monovalent and divalent ions. The green roof reduced the overall volume of runoff and served as a sink for NO3 - and NH4 +. However, the green roof was also a source for the pollutants PO4 3-, SO4 2-, TOC, cations, and total nitrogen. Metals such as zinc and lead showed trends of higher mass loads in the bare roof runoff than in precipitation and green roof runoff, although results were not statistically significant. The green roof also showed trends, although also not statistically significant, of retaining cadmium and copper. With the green roof serving as a source of phosphorous species and a sink for nitrogen species, and appearing to a retain metals and total volume, the life cycle impact analysis shows minimum impacts from the green roof, when compared with precipitation and bare roof runoff, in all but fresh water eutrophication. Therefore, the best environments to install a green roof may be in coastal environments.

Evaluation of the Design of Komendant's Cycloidal, Thin Shell Roofs At the Kimbell Art Museum Using Finite Element Analysis

The analysis of Komendant's design of the Kimbell Art Museum was carried out in order to determine the effectiveness of the ring beams, edge beams and prestressing in the shells of the roof system. Finite element analysis was not available to Komendant or other engineers of the time to aid them in the design and analysis. Thus, the use of this tool helped to form a new perspective on the Kimbell Art Museum and analyze the engineer's work. In order to carry out the finite element analysis of Kimbell Art Museum, ADINA finite element analysis software was utilized. Eight finite element models (FEM-1 through FEM-8) of increasing complexity were created. The results of the most realistic model, FEM-8, which included ring beams, edge beams and prestressing, were compared to Komendant's calculations. The maximum deflection at the crown of the mid-span surface of -0.1739 in. in FEM-8 was found to be larger than Komendant's deflection in the design documents before the loss in prestressing force (-0.152 in.) but smaller than his prediction after the loss in prestressing force (-0.3814 in.). Komendant predicted a larger longitudinal stress of -903 psi at the crown (vs. -797 psi in FEM-8) and 37 psi at the edge (vs. -347 psi in FEM-8). Considering the strength of concrete of 5000 psi, the difference in results is not significant. From the analysis it was determined that both FEM-5, which included prestressing and fixed rings, and FEM-8 can be successfully and effectively implemented in practice. Prestressing was used in both models and thus served as the main contribution to efficiency. FEM-5 showed that ring and edge beams can be avoided, however an architect might find them more aesthetically appropriate than rigid walls.

A parametric, experimental analysis of conical vortices on curved roofs of low-rise buildings

Different methods to reduce the high suction caused by conical vortices have been reported in the literature: vertical parapets, either solid or porous, placed at the roof edges being the most analysed configuration. Another method for alleviating the high suction peaks due to conical vortices is the use of some non-standard parapet configuration like cantilever parapets. In this paper the influence of roof curvature on the conical vortex pattern appearing on a curved roof (Fig. 1) when subject to oblique winds is experimentally analysed by testing the mean pressure distribution on the curved roofs of low-rise building models in a wind tunnel. Also, the efficiency of cantilever parapets to reduce mean suction loads on curved roofs is experimentally checked. Very high suction loads have been measured on curved roofs, the magnitude of these high suction loads being significantly decreased when cantilever parapets are used. Thus, the suitability of these parapets to reduce wind pressure loads on curved roofs is demonstrated.

Wind tunnel analysis on the influence of cantilever parapets on the wind loads on curved roofs

Different methods to reduce the high suction caused by conical vortices have been reported in the literature: vertical parapets, either solids or porous, placed at the roof edges being the most analysed configuration. Another method for alleviating the high suction peaks due to conical vortices is to round the roof edges. Very recently, the use of some non-standard parapet configurations, like cantilever parapets, has been suggested. In this paper, its efficiency to reduce suction loads on curved roofs is experimentally checked by testing the pressure distribution on the curved roof of a low-rise building model in a wind tunnel. Very high suction loads have been measured on this model, the magnitude of these high suction loads being significantly decreased when cantilever...

Computer analysis and design of concrete shell roofs

This paper is a preliminary version of Chapter 3 of a State-of-the-Art Report by the IASS Working Group 5: Concrete Shell Roofs. The intention of this chapter is to set forth for those who intend to design concrete shell roofs information and advice about the selection, verification and utilization of commercial computer tools for analysis and design tasks.The computer analysis and design steps for a concrete shell roof are described. Advice follows on the aspects to be considered in the application of commercial finite element (FE)computer programs to concrete shell analysis, starting with recommendations on how novices can gain confidence and competence in the use of software. To establish vocabulary and provide background references, brief surveys are presented of, first,element types and formulations for shells and, second, challenges presented by advanced analyses of shells. The final section of the chapter indicates what capabilities to seek in selecting commercial FE software for the analysis and design of concrete shell roofs. Brief concluding remarks summarize advice regarding judicious use of computer analysis in design practice.

Patent artificial slate manufactory, Woodford Bridge, Essex : for covering roofs, fronts of houses, and bricks : also water pipes and gutters.

Amendment leaf between p. 16-17.

Carpentry : being a comprehensive guide book for carpentry and joinery : with elementary rules for the drawing of architecture in perspective and by geometrical rule : also, treating of roofs, trussed girders, floors, domes, stair-cases and hand-rails, shop fronts, verandahs, window-frames,shutters, &c. &c., and public and domestic buildings, with plans, elevations, sections, &c. &c./

Mode of access: Internet.

Guidelines for the installation of solar components on low-sloped roofs /

"Issued November 1980."

Treatise on the theory of the construction of bridges and roofs ...

Mode of access: Internet.

A text-book on roofs and bridges,

pt. 1. Stresses in simple trusses. 6th ed., rewritten and enl., 1905.--pt. 2. Graphic statics. 3d ed., enl., 1897.--pt. 3. Bridge design. 4th ed., rewritten, 1902.--pt. 4. Higher structures. 3d ed., rev. and enl., 1907.

The carpenter and joiner's assistant. Containing practical rules for making all kinds of joints, and various methods of hingeing them together ... to which are added, examples of various roofs executed ... also extracts from M. Belidor, M. du Hamel, M. de Buffon, etc., on the strength of timber with practical observations.

Mode of access: Internet.