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Browsing by discipline "Multidisciplinary studies on Urban Environmental Issues"

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  • Tsui, Ka Man (2015)
    Forest certification has been used as a tool to promote forestry responsibility towards sustainable forest management. Forest Stewardship Council (FSC) is one of the certification systems that is well recognised in Europe. Nevertheless, compared to other European countries, the number of FSC chain of custody (CoC) certifications in Finland is relatively low. Semi-structured interviews were conducted with six FSC CoC certified companies to explore their experiences towards implementing and maintaining the system in their companies. The sample group was comprised of wood and paper product industries in manufacturing and trading sectors. Thematic analysis of the interviews revealed the challenges companies encountered. The results indicated that there were eight types of challenges, including three internal and five external ones, hindering the development of FSC CoC certification in Finland. Internal challenges included competence, financial resources, and a lack of motivation to change. External challenges included insufficient marketing and demand, uncertain cost benefit, keen competitor programmes, limited supply, and long trademark approval time. Meanwhile, the relevant solutions these companies adopted to deal with the challenges were discussed. Since external challenges out-numbered internal ones, it seemed that certified companies are not able to tackle the existing challenges alone. Joint-effort among other actors in the forestry sector, for instance, the national authority, FSC national office, certification bodies are essential to influence the rate of certification uptake. Furthermore, participants discussed about the future development of FSC CoC certification system in Finland. Interviewees believed that the enactment of the EU Timber Regulation (EUTR) and the introduction of forest certification into national public procurement policy could positively impact the development of the system. The results of this study could be used as a reference for potential certificate users to prepare themselves for implementing FSC CoC certification system. In addition, the study could shed a light on the development of FSC in Finland in the future.
  • Collins, Steven G. (2016)
    Cities of the 21st century consume massive amounts of energy, and indoor climate control within the built environment is responsible for a large fraction of the total demand. With pressures to make buildings more environmentally friendly, new energy efficient technologies and designs are continually sought after. A green roof, or a living roof, is a structural design approach that can provide a variety of ecosystem services along with the reduction of building energy demands. It has been shown that green roofs are effective tools for reducing cooling energy demands in warm and sunny climates; however, in cold climates, where heat energy demands dominate, there is a lack of research and general uncertainty about how beneficial a green roof may be. This thesis, conducted during the winter of 2013-2014, focused on the thermal performance of green roofs in cold weather (winter) conditions. The aim of the study was to quantify the reduction in energy loss that a green roof achieves and to examine the thermal behaviour of each of the green roof layers. Extensive green roofs with hot boxes underneath were constructed in Lahti (southern Finland). Heat sensors were placed vertically through the bare and green roofs to measure linear heat transfer from the interior to the exterior. Heat transfer by conduction was assessed, and a steady state analysis was used to quantify heat flux values. Furthermore, a green roof thermal conductivity model was developed to estimate the thermal conductivity of each of the layers under various environmental conditions (changing moisture contents, frost depths, and during freezing and thawing periods). Monthly comparisons of the energy lost through the two roofing structures were quantified. My results showed that green roofs reduced the amount of energy loss through the surface compared to bare roofs throughout the winter season. The overall reduction in energy loss, due to the presence of green roofs, was on average, 32.6%. Layer analysis showed that thermal conductivity of each of the layers decreased when penetrated by frost. A frost depth that extended through the whole green roof yielded the highest thermal resistance for the green roof at 3.96 m2KW-1. Comparatively, the bare roof had a thermal resistance of 0.27 m2KW-1. During times of snow coverage, the snow acted as a good thermal insulator, reducing the relative benefits achieved from green roofs. During refreezing and thawing, the green roof experienced the lowest values of thermal resistance at 1.83 m2KW-1. These results can be used for quantifying possible heat loss reductions in similar climates using a similar green roof, and the layer analysis provides information of how to best design green roof components for thermal resistance.