scholarly journals Measurement of the runoff coefficient of extensive greenroof

2021 ◽  
Vol 1209 (1) ◽  
pp. 012034
Author(s):  
J Vystrčil ◽  
O Nespešný ◽  
K Šuhajda ◽  
D Bečkovský ◽  
P Selník
Keyword(s):  
Boundary Conditions ◽  
Experimental Measurement ◽  
Green Roofs ◽  
Measured Data ◽  
Experimental Measurements ◽  
Nonlinear Behaviour ◽  
Runoff Coefficient ◽  
Extensive Green Roof ◽  
Method Of Evaluation ◽  
Extensive Green Roofs

Abstract Describes the procedure of experimental measurement of the runoff coefficient C, both of individual layers and the entire composition extensive green roofs. Experimental measurements make it possible to determine the reference behaviour of runoff characteristics, namely runoff coefficient C, with emphasis on the simulation of the real behaviour of extensive green roofs. The aim is an elementary description of the structural and physical behaviour of extensive green roofs. For the needs of experimental measurement, the dimensional and shape limits of test specimens are described, the conditions for conditioning of individual specimens, the boundary conditions of execution and individual steps of the experiment. Then is specified the method of evaluation and subsequent verification of measured data. The result of the experimental measurement is the amount of drained water from the tested specimens of the extensive green roof at time t, which shows a nonlinear behaviour. From the set of measured data, it is then possible to predict the behaviour of extensive green roofs in real conditions and to determine the runoff coefficient C of the tested specimens. These data represent reference values for the subsequent design of sub-elements and structures of buildings.

scholarly journals Hydrologic Performance of an Extensive Green Roof under Intensive Rain Events: Results from a Rain-Chamber Simulation

2021 ◽  
Vol 13 (6) ◽  
pp. 3078
Author(s):  
Elena Giacomello ◽  
Jacopo Gaspari
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
International Standards ◽  
Dimensionless Number ◽  
Runoff Coefficient ◽  
Retention Performance ◽  
Extensive Green Roof ◽  
Rain Events ◽  
Hydrologic Performance

The water storage capacity of a green roof generates several benefits for the building conterminous environment. The hydrologic performance is conventionally expressed by the runoff coefficient, according to international standards and guidelines. The runoff coefficient is a dimensionless number and defines the water retention performance over a long period. At the scale of single rain events, characterized by varying intensity and duration, the reaction of the green roof is scarcely investigated. The purpose of this study is to highlight how an extensive green roof—having a supposed minimum water performance, compared to an intensive one—responds to real and repetitive rain events, simulated in a rain chamber with controlled rain and runoff data. The experiment provides, through cumulative curve graphs, the behavior of the green roof sample during four rainy days. The simulated rain events are based on a statistical study (summarized in the paper) of 25 years of rain data for a specific location in North Italy characterized by an average rain/year of 1100 mm. The results prove the active response of the substrate, although thin and mineral, and quick draining, in terms of water retention and detention during intense rain events. The study raises questions about how to better express the water performance of green roofs.

The biodiversity of temperate extensive green roofs – a review of research and practice

2016 ◽  
Vol 62 (1-2) ◽  
pp. 44-57 ◽  
Author(s):  
Christine Thuring ◽  
Gary Grant
Keyword(s):  
Green Roof ◽  
Green Roofs ◽  
Ecological Design ◽  
Ecological Research ◽  
Extensive Green Roof ◽  
Research And Practice ◽  
Climatic Regions ◽  
History Of ◽  
Research To Policy ◽  
Extensive Green Roofs

From its beginnings in Germany in the twentieth century, a thriving extensive green roof industry has become established in many countries in temperate climates. Based upon the success of the industry, and with an expectation that this technology will be adopted in other climates, this review of the ecological research of extensive green roofs aims to evaluate the application of this knowledge. The modern extensive green roof is the product of research in the 1970s by German green roof pioneers; the selection of suitable species from analogue habitats led to green roof vegetation dominated by drought tolerant taxa. The commercial success of extensive green roof systems can be attributed to engineering and horticultural research, to policy mechanisms in some places, and to a market that encourages innovation, and the origins in ecological design are now easily overlooked. Some of the work reviewed here, including the classification of spontaneous roof vegetation into plant communities, is not widely known due to its confinement to the German literature. By re-visiting the history of the extensive green roof and reviewing the ecological research that has contributed to our understanding of it, the intention is, for this paper, to inform those considering green roofs in other climatic regions, to apply an ecologically informed approach in using local knowledge for developing installations that are suited to the bioregion in which they occur. Finally the paper considers some future directions for research and practice.

scholarly journals Applications of Extensive Green-roof Systems in Contributing to Sustainable Development in Densely Populated Cities: a Hong Kong Study

2011 ◽  
Vol 11 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Vivian W. Y. Tam ◽  
Xiaoling Zhang ◽  
Winnie Lee ◽  
LY Shen
Keyword(s):  
Hong Kong ◽  
Air Temperature ◽  
Current Practice ◽  
Green Roof ◽  
Green Roofs ◽  
Existing Building ◽  
Extensive Green Roof ◽  
High Rise ◽  
Urban Greenery ◽  
Extensive Green Roofs

Developed cities such as Hong Kong are usually densely populated. Since the land is limited, high-rise buildings are constructed. When the building height becomes higher, air flow is reduced and heat is trapped among high-rise buildings. Air temperature will be greatly increased and air pollution becomes a serious problem. This creates a walled building problem. To reduce air temperature caused by the wall-effects, various methods have been developed in the previous studies. One typical method is the use of green roof systems. The application of extensive green roofs on the existing building rooftops has been recommended in Hong Kong since 2001. The advantage of this practice is that no additional floor area is required and it can also improve urban greenery. Although a green roof system has been introduced and adopted in Hong Kong since 2001, the emphasis is mainly given to the application of intensive green roofs for podium garden instead of extensive green roofs. It is considered valuable and necessary of the extensive green roofs for the buildings. This paper investigates the current practice of using extensive green roofs in Hong Kong. The constraints in applying extensive green roofs are investigated, which leads to studying the solutions for mitigating these constraints and improving the future development of the implementation.

The Comparison of the Probabilistic Calculation of Course of Temperatures in Peripheral Construction with Actual Measured Data

2014 ◽  
Vol 1041 ◽  
pp. 154-157 ◽  
Author(s):  
Denisa Donová ◽  
Naďa Zdražilová
Keyword(s):  
Boundary Conditions ◽  
Measured Data ◽  
Experimental Measurements ◽  
Actual Behavior ◽  
Passive House

This article deals with probabilistic calculation of the behavior of the peripheral wallof the wooden passive house in terms of the temperatures inside the structure in the winter. The probabilistic calculation was made for the actual boundary conditions, ie. actually measured exterior and interior temperature. The results of the probabilistic calculation are ultimately compared with the results of experimental measurements of temperature inside the structure, ie. the actual behavior of the structure.

scholarly journals Moisture Content of Extensive Green Roof Substrate and Growth Response of 15 Temperate Plant Species during Dry Down

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 518-522 ◽  
Author(s):  
Jennifer M. Bousselot ◽  
James E. Klett ◽  
Ronda D. Koski
Keyword(s):  
Moisture Content ◽  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Extensive Green Roof ◽  
Dry Down ◽  
Porous Soils ◽  
Extensive Green Roofs

Success of extensive green roof vegetation depends primarily on associated plant species' ability to survive the low moisture content of the substrate. As a result of the well-drained nature of the substrate, plants adaptable to dry, porous soils are primarily used in extensive green roof applications. Although Sedum species have dominated the plant palette for extensive green roofs, there is growing interest in expanding the plant list for extensive green roof systems. To effectively select suitable plants, species need to be evaluated in terms of their response to gradual and prolonged dry down of the substrate. A study to determine the relative rates of dry down for 15 species was conducted in greenhouse trials. During dry downs that extended over 5 months, the substrate of succulent and herbaceous species dried down at different rates. The change in moisture content of the substrate was not consistent among succulent and herbaceous plant species during the initial 18 d of dry down. Despite differences in rate of dry down, the succulent species, as a group, maintained viable foliage for over five times longer than the herbaceous species. The revival rates of the succulent species were nearly double those of the herbaceous species. Therefore, not only are succulent species more likely to survive during periods of drought, but these species are more likely to resume growth soon after water is again made available.

scholarly journals AVALIAÇÃO DO DESEMPENHO AMBIENTAL NA UTILIZAÇÃO DE TELHADOS VERDES EXTENSIVOS EM ESCOLAS PÚBLICAS DO PARANÁ

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Isaura Marques De Souza Uhmann ◽  
Sérgio Fernando Tavares
Keyword(s):  
Public Schools ◽  
Public Administration ◽  
Green Roofs ◽  
School Buildings ◽  
Extensive Green Roof ◽  
Design Change ◽  
State Institutions ◽  
Standard Design ◽  
Extensive Green Roofs

RESUMO: Em um contexto onde a arquitetura discute seu papel na busca por um mundo mais sustentável, destaca-se a presença destes aspectos no edifício escolar. No Brasil as condições de projeto e manutenção deste tipo de construção não são as mais adequadas. Dentre os problemas que mais afligem esta tipologia arquitetônica estão às más condições das coberturas, que além de prejudicar sua utilização pelos usuários comprometem a edificação, diminuindo sua vida útil. O objetivo dessa pesquisa é avaliar índices de Energia Embutida EE e emissão de CO2 entre o sistema de cobertura tradicional e o sistema de telhado verde extensivo proposto para substituição das coberturas originalmente implementadas nas escolas da rede pública do Paraná. A pesquisa tem natureza exploratória com aplicação em estudo de caso. Para estes estudos foi utilizada a formatação em planilhas, cuja estratégia é avaliar a substituição das coberturas convencionais por telhados verdes, atendendo orientações da legislação de licitações, administração pública e convênios com a participação de instituições estatais. Os dados de Energia Embutida EE e emissão de CO2 avaliados apontam para a viabilidade na implementação da readequação por telhados verdes extensivos. A principal contribuição deste trabalho é a implementação de uma técnica mais sustentável em edificações públicas escolares podendo inclusive apontar para novas posturas na concepção e execução de obras desta natureza ABSTRACT: In a context where the architecture discusses its role in the search for a more sustainable world, there is the presence of these aspects in the school building. In Brazil design conditions and maintenance of this type of construction are less suitable. Among the problems that afflict most school buildings are to poor coverage, which in addition to discomfort for users to undertake the life of the building. The objective of this research is to evaluate rates of EE embedded energy and CO2 emissions between traditional roofing system and extensive green roof system proposed to replace the covers originally implemented in Paraná public schools. The research is exploratory in nature with application case study. For these studies we used the formatting in spreadsheets, thus meeting guidelines bidding law, public administration and agreements with the participation of state institutions. The strategy is to evaluate through simulation tables, replacing the conventional covers for green roofs. Data assessed in these simulations indicate the feasibility for implementation by readjusting the extensive green roofs, thus using more sustainable technology. It is also observed the feasibility of a standard design change currently in effect.

DESIGN OF EXTENSIVE GREEN ROOFS FOR THE MAJOR SCHOOL PLANTS OF PIRAEUS

2015 ◽  
pp. 959-966 ◽  
Author(s):  
G. Varras ◽  
K.-TH. Vozikis ◽  
C. Myriounis ◽  
I.L. Tsirogiannis ◽  
E. Kitta
Keyword(s):  
Green Roofs ◽  
Extensive Green Roofs
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