Building Integrated Vegetation Systems and their Sustainability Aspects; A Literature Review

Abstract:There is a growing need of sustainable building development all over the world. It aims to decrease the adverse effects to the environment due to urbanization and escalating population growth. Since the building construction is considered as one of the main concerns, the priority was given to mitigate the negative impact to the environment. Therefore, incorporating sustainable elements and techniques to the buildings to regain the land loss due to construction activities in cities is currently practicing. Adding various vegetation types through different approaches, to obtain the expected results of better living condition around the building is called as building integrated vegetation systems (BIV). Vertical gardening systems, vertical farms, constructed green roofs and roof farms can be stated as main categories of BIV systems. However, there is a paucity of published critical reviews on such systems and therefore, this study is an attempt to review the overall sustainability aspects of BIV systems including environmental sustainability, economic sustainability and social sustainability. This study consists with a critical review of 114 research publications from relevant journals and online scientific databases. Finally, the identified sustainability aspects of each BIV systems were analyzed to select the best option in terms of greening a building which can be recommended for the implementations in future. Mainly, the importance of moving towards the sustainable solution which meets the food needs through BIV is finally discussed. Finally, it can be concluded that by incorporating green architecture with smart agriculture, we can expect green, healthy and productive cities which fulfill the main requirements of sustainable cities. Though there are many challenges to overcome, maintaining good management practices will give better output. Out of the 114 literature selected for this study, only 8 research papers were discussed about the drawbacks and the limitations of the BIV systems which is still having paucity of information. Keywords: Building Integrated Vegetation systems, Economic Sustainability, Environmental Sustainability, Social Sustainabilit

Energy content of walling materials- a comparison of mud concrete blocks, bricks cabook and cement blocks in tropics

The concept of embodied energy can be used to understand and develop energy saving products or services. By definition the embodied energy is sum of all the types of energy consumed while producing specific product or a service. The embodied energy can be calculated by dividing the total; process of production and measuring each and every process energy consumption. The mud concrete block is a novel ecological walling material. The intention of this paper is to calculate embodied energy and carbon emission, compare in a real world scenario of constructing one square (10ft x10ft) wall of mud concrete block and compare with industrialized walling materials such as brick and cement blocks. The energy consumption of mud concrete block was on account of transport of raw materials (cement) to the factory and the already embedded energy of cement. The cement was a governing raw material in adding energy content to the total embedded energy of mud concrete block. The brick showed comparatively highest embedded energy. And the cement block had intermediate energy content. The Brick production was using more or less sustainable energy sources such as bio mass, bio mass is renewable. But mud concrete block and cement block using non renewable energy sources which can be replaced by renewable energy source

Improve intrinsic properties of walling materials to create occupant comfort

Abstract Buildings and architectural spaces are built for occupant comfort. Thus tropical climatic condition is the worst climate to achieve the occupant comfort. Tropics are favourable for bio receptive activities such as fungus and moss. Fungus and moss produce mycotoxins, spores and fragments which are toxic to occupants. However, the relationship between buildings envelops and bio receptivity should be studied prior to find a sustainable solution. This study was conducted to understand the relationship with intrinsic properties of wall construction materials and the bio receptivity. The study was conducted after studying several intrinsic properties of walling materials such as organic matter content, surface roughness, water absorption and pH value according to laboratory test standards. Fungus and moss growth standard tests were conducted in the real world-controlled environment. Results of this study showed that surface roughness is the significant intrinsic property on bio receptivity. According to the test results fungus and moss growth on walling materials has a reciprocal connection with surface roughness values and no growth occurs on wall plasters where the surface is smoother. This study concluded that covering walls with cement plaster can reduce the growth of moss and fungus on tropical homes. Therefore smooth, plastered surfaces are best for homes with occupant comfort. But the cost of plastering might prevent poor families from acting on this concept. Therefore it is necessary to develop sustainable, cost effective and environmentally friendly wall, smoothing materials and techniques

Influence of Street Tree Canopy on the Microclimate of Urban Eco-Space

Rapid population and urban growth increase the vulnerability of tropical cities to climate change. Substantial modifications in urban eco-space with current development trends and urbanisation create Urban Heat Island (UHI) effect. UHIs represent dense urban areas within cities where the temperature is recorded to be higher than those located in suburbia. UHI induces through lowalbedo surfaces, building geometry and loss of green infrastructure in urban setting, causes a huge influence on the quality of life of urban dwellers. Expanding urban forest through street tree planting is considered as one of the most cost-effective means of mitigating the urban heat island effect and associated expenditures for air conditioning. This study evaluates (a) the relationshipbetween the radiation cut off by street tree canopy and the changes in ambient temperature and the RH in Colombo Metropolitan Region (CMR) (b) the street tree species with the highest thermal and RH benefit from the abundant street trees in CMR (c) the average ambient temperature and RH benefit to the urban environment from street trees through a simulation study using ENVI-met 4.4 software version. Hence, the study comprises with a field assessment along six main selected streets in Colombo city and a computer-based simulation study using ENVI-met 4.4. The ambient temperature change and the RH change under the street tree canopies in the CMR has a positive correlation with the amount of radiation cut off from the tree canopy. From the studied street tree species Mesua ferrea recorded the highest thermal and RH benefits and those were 3.8° C and 7.2%, respectively. Simulation study indicated that by increasing the street tree canopy by 2,3 and 4 folds than existing, the modelled area of CMR (Wellawatta city) can receive a thermal benefit of 1.280° C, 1.37° C, 1.63° C and a RH benefit of 1.99%, 2.77%, 3.94%, respectively. Hence, the average ambient temperature drop and RH increase from a single tree to a wider area (Wellawatta city) was 0.53o C and 1.34%, respectively. Consequently, by enhancing urban forest cover through strategic establishment of street trees urban environment and outdoor thermal comfort of tropical Sri Lanka can be enhanced effectively.Keywords: ENVI-Met, Street trees, Urbanisation, Urban Heat Island (UHI

Accumulate and consolidate the traditional vernacular timber preservation technologies through a field survey

There are remarks on diverse types of timber structures in the tropics. This paper examines several case histories in Sri Lanka, focusing on the culturally varied and ecologically diverse traditional buildings with wood used for construction. The main objective was to gather data and document the knowledge on wood preservation. Information was gathered through face-to-face interviews with 270 individuals’ reference to 138 structures. A holistic analysis was performed to understand the techniques used to overcome the degradation mechanisms and state of conservation. The demographic profile of the informants was evaluated and cross-relationships on the tabulated data were analyzed by SPSS statistical software following the snow-balling sampling technique. There were three main preservation techniques identified from the open-ended questions namely, wood kept under smoke pits, wood kept under paddy field mud, and wood kept under the river banks. Preserving wood by keeping it under paddy field mud (49.62 %) was the highest recorded answer. The most obtained material matrix of preservation was plant origins (48.88 %). For generations, people have transmitted traditional and cultural practices through oral knowledge. The results conclude this knowledge places a high value on protecting construction technologies and applications while preserving biodiversity. Unfortunately, by today this technology has started extinct. The results revealed the importance of social norms and cultural perceptions as a set of valuable information that was practiced with a great history in a tropical country