Understanding the Challenges of Implementing Green Roofs in Multi-Family Apartment Buildings:A Case Study in Khulna

Green roofs are widely recognized for their multifaceted benefits to the environment,economy,and society,constituting the fundamental pillars of sustainability.These roofs contribute to the enhancement of bio-physical diversity,provision of food resources,regulation of temperature and rainfall-runoff patterns,creation of wildlife habitats,and augmentation of aesthetic and recreational value.While Bangladesh,with its favourable climatic conditions and rapid urbanization,possesses immense potential for harnessing the advantages of green roofs,their adoption remains limited in both research and practical applications within the country.Addressing this research gap,the present study aims to investigate the barriers impeding the implementation of green roofs in existing or new multi-family apartment buildings,focusing specifically on the city of Khulna.Through a combination of case studies and a comprehensive questionnaire survey administered to diverse stakeholders including apartment dwellers/owners,architects,developers,and government officials with varying levels of expertise,this research sheds light on the obstacles hindering Green Roof Implementation(GRI).The identified barriers encompass a lack of governmental policies,inadequate technological advancements,inaccurate estimation of economic benefits,and individual resistance.In light of the perspectives of various GRI stakeholders,strategic proposals encompassing policy,technical,economic,and social dimensions are presented to surmount these barriers.The outcomes of this study contribute to the dissemination of knowledge pertaining to the impediments to GRI implementation,thereby inspiring further research endeavours and enabling decision-makers to formulate robust policies facilitating the widespread adoption of green roofs.

Green roofs for storm water management:a review

The rapid urbanization and industrialization involve an unsustainable use of natural systems,leading to various problems in cities.The urban hydrological system experiences fluctuating amount of surface runoff water when it rains heavily.It has been suggested that green roofs significantly mitigate storm water runoff generation even in tropical climate.Green roofs have become popular due to its proven benefits by mitigating urban heat island effects and protecting biodiversity.The annual rainfall and runoff relationship for green roofs is determined by the depth of the substrate.Water retention capacity mostly depends on substrate's physical conditions such as dry or wetness.Generally 6 mm to 12 mm rainfall is required for dry substrate to initiate runoff whereas response of wet conditions is mostly straight.Besides,there are some other factors affecting runoff dynamics such as type of a green roof and its slope,age of green roof,type of vegetation,soil moisture characteristics,weather.The review indicates that there is not much research in green roofs performance over storm water runoff;hence there is a need for further research.This paper reviews and addresses the role of green roofs in urban storm water management.

Vegetation composition of old extensive green roofs(from 1980s Germany)

Introduction:Since their development in the late 1970s in Germany,extensive green roofs(EGR)have become increasingly popular as mitigation tools for urban environmental issues around the world.EGRs are planted with select species,which ensure consistent cover and performance over time.This research presented herein is part of a systematic re-evaluation of EGR technology since the German industry began.Methods:Given the opportunity to access a small sample of old EGRs installed over 20 years ago in south-west Germany,this research surveyed the vegetation and substrate with an interest in describing these parameters with time-through-space substitution.Results:Similar to previous studies,this preliminary work found correlations between roof age with vegetation(cover abundance and species diversity)and substrate properties(e.g.,depth,organic content,pH,and nutrients).Roof age had positive relationship with soil organic content(Corg),and negative relationships with substrate depth and soil pH.These soil variables are inter-related,as shallow acidic substrates create unfavourable conditions for decomposition and thereby the accumulation of duff.Substrate variables correlated with EGR vegetation,suggesting a trend of simplified species composition over time.Indeed,Corg had a negative relationship with cover and species diversity of most life forms;only Sedum species had positive associations with Corg.Conclusions:Considering the dynamics associated with shallow mineral substrates,and the greater floristic diversity of younger roofs,simple Sedum-based vegetation may represent a steady state for conventional EGRs.

Do green roofs really provide significant energy saving in a Mediterranean climate? Critical evaluation based on different case studies

Green roofs represent a growing technology that is spreading increasingly and rapidly throughout the building sector.The latest national and international regulations are promoting their application for refurbishments and new buildings to increase the energy efficiency of the building stock.In recent years,vegetative coverings have been studied to demonstrate their multiple benefits,such as the reduction of the urban heat island phenomenon and the increase in the albedo of cities.On the contrary,this study aims to verify the actual benefit of applying a green roof on a sloped cover compared with installing a highly insulated tiled roof.The EnergyPlus tool has been used to perform dynamic analyses,which has allowed to understand the behavior of two different stratigraphies in accordance with weather conditions,rain,and irrigation profiles.Results have shown that the installation of a green roof cannot always be considered the best solution for reducing building energy consumption,especially if compared with a classic highly insulated clay tile roof.In terms of summer air conditioning,the maximum saving is 0.72 kWh/m2.The presence of water in the soil has also been proven a crucial factor.

Green Roof Performance for Stormwater Management in Equatorial Urban Areas Using Storm Water Management Model (SWMM)

Many Low Impact Developments (LIDs) have recently been developed as a sustainable integrated strategy for managing the quantity and quality of stormwater and surrounding amenities. Previous research showed that green roof is one of the most promising LIDs for slowing down rainwater, controlling rainwater volume, and enhancing rainwater quality by filtering and leaching contaminants from the substrate. However, there is no guideline for green roof design in Malaysia. Hence, Investigating the viability of using green roofs to manage stormwater and address flash flood hazards is urgently necessary. This study used the Storm Water Management Model (SWMM) to evaluate the effectiveness of green roof in managing stormwater and improving rainwater quality. The selected study area is the multistory car park (MSCP) rooftop at Swinburne University of Technology Sarawak Campus. Nine green roof models with different configurations were created. Results revealed that the optimum design of a green roof is 100 mm of berm height, 150 mm of soil thickness, and 50 mm of drainage mat thickness. With the ability to reduce runoff generation by 26.73%, reduce TSS by 89.75%, TP by 93.07%, TN by 93.16%, and improved BOD by 81.33%. However, pH values dropped as low as 5.933 and became more acidic due to the substrates in green roof. These findings demonstrated that green roofs improve water quality, able to temporarily store excess rainfall and it is very promising and sustainable tool in managing stormwater.

Research on Ventilation and Heat Insulation Layer Design of Split-Type Roof Greening Based on Topological Interlocking Principle

In this paper,the roof ventilation and heat insulation layer modules are combined with the roof greening,and each module is assembled through the principle of topological interlocking.The assembly of these modules does not require any rivets or cement mortar,and the structural stability of the overall assembled roof is achieved only through the interlocking and limiting the movements of the interlocked units.The green roof designed in this paper has strong applicability and can be applied to roofs of different shapes.Such a roof can not only meet the aesthetic needs,but also beautify the urban environment and reduce carbon emissions.

Irrigation and Thermal Buffering Using Mathematical Modeling

Two methods of irrigation,drip,and sprinkler were studied to determine the response of the Javits green roof to irrigation.The control study was dry unirrigated plots.Drip irrigation consisted of irrigation tubes running through the green roof that would water the soil throughout and sprinkler irrigation used a sprinkler system to irrigate the green roof from above.In all cases,the irrigated roofs had increased the soil moisture,reduced temperatures of both the upper and lower surfaces,reduced growing medium temperatures and reduced air temperatures above the green roof relative to the unirrigated roof.The buffered temperature fluctuations were also studied via air conditioner energy consumption.There was a 28%reduction in air conditioner energy consumption and a 33%reduction in overall energy consumption between dry and irrigated plots.Values of thermal resistance or S were determined for accuracy and for this study,there was little change which is ideal.A series of infra-red and thermal probe measurements were used to determine temperatures in the air and sedum.It was determined that the sprinkler irrigation did a better job than the drip irrigation in keeping cooler temperatures within the green roof.A Mann-Whitney U test was performed to verify the variation in moisture temperatures buffering energy consumption.By getting a p-value<0.05,it indicates that the model is accurate for prediction and medium temperatures were statistically different.

Developmental Application of Roof Greening against the Background of “Sponge City”: A Case Study of Ningbo City

In view of the problems of architectural eco-civilization in Ningbo City against the background of "sponge city", this paper proposed that development of roof greening in the city met the development concepts of sponge city, summarized six basic countermeasures and four cooperation mechanisms for the developmental application of roof greening in Ningbo City by analyzing practical experience of roof greening construction in foreign countries.

Application of Green Roof in Relieving Urban Waterlogging: A Review

Green roof plays a critical role in regulating roof runoff by reducing runoff, delaying runoff generation, reducing runoff peak flow and improving runoff water quality effectively. On the basis of introducing significance and role of green roof, this paper reviewed domestic and international researches on the green roof's control over roof runoff, and analyzed the factors that influence the control of green roof over the runoff, so as to provide a theoretical support and method for the construction of green roofs in urban districts.

Case Study:Topography Integrated Urban Center Concept Project on Coastal Line of Kartal/İstanbul

The concept of creating a Topography integrated urban center is to create an urban center that integrated with the city.The first step of the Concept is to settle by using the natural elevation in the land and to create volumes compatible with land by raising together with the elevation.While the passenger circulation at starting elevation is moved into a project with the cavestyle volume settled in land elevation.The new area of the square to be defined in the center of the building is intended to form an area combining the neighboring squares Kartal Square and Freedom Square,as well as contributing to the silhouette of Kartal from the sea with the location of the square and building.The project is a central complex design that deals with various urban problems thanks to professionals,local people of Kartal,and clubs which established with the municipality in a comprehensive way to search for solutions to be organized urban workshops and conferences.

Analysis of Products Related to Vegetation Blanket

Roof greening has gradually become an important component of urban greening. Because of the advantages of low building load and low price,vegetation blanket roof greening has gradually become a widely spread technology of roof greening. In this paper,the characteristics of vegetation blanket roof greening technology are analyzed and summarized,and reasonable suggestions are provided for construction.

Effects of green roof damping and configuration on structural seismic response

Sustainable structures are critical for addressing global climate change.Hence,their structural resilience or ability to recover from natural events must be considered comprehensively.Green roofs are a widely used sustainable feature that improve the environment while providing excellent occupant amenity.To expand their usage,their inherent damping and layout sensitivity to seismic performance are investigated in this study.The soil of a green roof can serve as a damper to dissipate the energy generated by earthquakes or other dynamic events.Results of preliminary analysis show that a green roof soil can increase localized damping by 2.5%under both dry and saturated conditions.Based on these findings,nonlinear time-history analyses are conducted on a three-story building in SAP2000 to monitor the structural behavior with and without a green roof.The increased damping in the green roof soil is beneficial to the structural performance,i.e.,it reduces the building displacement and acceleration by 10%and 12%,respectively.Additionally,certain configurations are more effective and beneficial to the structural response than others,which suggests the possibility of design optimization.Based on the findings of this study,new methods of modeling and considering green roofs in structural design are established.

Green Rails Over the World’s Roof

The Qinghai-Tibet Railway sets a model for environment-friendly development In summer the vast wildness of Qinghai-Tibet Plateau in west China teems with life. And while the plateau is home to a stunning range of wildlife, the

Retrofitting with vegetation recent building heritage applying a design tool--the case study of a school building

Severaf researches show the environmental and microclfmatic benefits of the （ntegration of vegetation in architecture; however the potentialities of vertical and horizontal greening systems to retrofit buildings are still not much investigated. The retrofitting project of the Barsanti Institute of Camogli （Genoa, Italy） is presented, a building dated back to the sixties with serious architectural and efficiency problems, located in a considerable Landscape area. The development and application of a design tool （process tree）, for horizontal and vertical greened surfaces, allows to evaluate the potentialities of vegetation to retrofit and to relate the encountered efficiency problems and the climate characteristics with the choice of plant species, system, and technology more suitable for the specific situation （of which environ- mental and economic impact are also evaluated） and to define a design approach for the systematic consideration of the many parameters involved. ~ 2013. Higher Education Press Limited Company. Production and hosting by Elsevier B.V. All rights reserved.

Comparison of thermal performance between test cells with different coverage systems for experimental typical day of heat in Brazilian Southeastern

This article shows experimentally the thermal performance of two test cells with different coverage systems, Ught Green Roof （LGR） and ceramic roof by analyzing internal surface temperatures （IST） in the ceiling and dry bulb temperatures （DBT）. The objective was to evaluate the spatial distnbution of temperatures in buildings according to spatial and temporal Dynamic CUmato[ogy approaches. An experimental, typical day for heat conditions was determined. The data of the main climatic vari- ables provided by an automatic weather station and temperatures inside the test cells were collected using thermocouples installed such that the entire space is included. The results led to the conclusion that the LGR has a balanced IST and DBT spatial distribution compared with ceramic roofs. Nevertheless, the analysis of the thermal performance is only one of the variables that must be considered when developing a construction proposal that is adapted to the context. The manner in which the thermocouples were placecl inside the test cells also showed the importance of specifying the location of the sensors in experimental studies on the behavior and thermal performance of buildings.

Assessment of terrace gardens as modifiers of building microclimate

Hard concrete roofs cause excessive heat gain impacting thermal comfort in buildings.Terrace gardens promoting greening at higher levels of built structures are seen as one of the key mitigating strategies for modifying building microclimate and improving urban health.We have undertaken a research project to quantitatively assess the value of a terrace garden in a residential scale.A garden patch of about 15 m 2 in area,a typical size available in most urban terraces is developed.Surface temperatures are measured over a period of 15 months between July 2018 to January 2020 using four thermocouple sensors,placed within and outside the garden bed,on and below the roof.We compare the thermal performance of the terrace garden across years,seasons,time of the day,presence or absence of garden bed and type and height of vegetation.The surface temperature data was found to correlate well with the ambient air temperature values.The results show that the terrace garden moderates and stabilises the ceiling temperatures and reduces it by about 2-3°C in winter months and 5-7°C in hot summers.The garden also provided nearly 400 g of fresh monthly vegetable harvest per m 2 of garden.Further,the cooling impact of the terrace garden with natural,tall,wild vegetation is higher as compared to planted vegetation.The study demonstrates a sustainable approach to terrace garden design at residential scale through quantified dual benefits of temperature control within buildings and urban farming.