Hur påverkas miljön av limträ- eller stålstomme för en lantbruksbyggnad?

Sammanfattning: Global climate change is one of the most important tasks that scientists are trying to solve today. With the help of a Lifecycle Analysis (LCA) method, the impact that many materials and services have on the environment and humans, have been determined.  As a task given by Gävleborg County Administrative Board, this work examines which of the material, glulam or steel, is most suitable as load-bearing material for agricultural buildings (barns). The goal of this study is to perform a LCA (Life Cycle Assessment) of the two materials during production, use, transportation and reuse. The steel's advantage is to be reused again without losing its properties and the wood's benefits to be used as an energy source during combustion, is only one of the steps involved in a life cycle analysis.  The information that an LCA study requires can be infinite and complex and therefore needs limitations in resources and time. A system boundary makes a basis on which phases and influences are the vital parts of a study. The system boundary also includes geographical areas. The study examines only local agricultural buildings in Gävleborg, Sweden, with floor areas of approximately 1300 m2 and their global environmental impact.  Environmental impact of a product is usually allocated in several different environmental impact categories, in which the study examines only three of these: global warming, acidification and eutrophication.  The results show a great difference in emissions depending on how the materials are produced and how they are handled after use. It proves that glulam has significant fewer emissions than steel when it used as an energy source instead of being deposited. With help of the weighting method the result show that iron ore produced steel have 1.2 times greater emission then glulam with landfill and 5.2 times greater when it is used in energy recovery. The weight also shows that scrap produced steel have 0.5 less emission than glulam with landfill and 2.4 greater than glulam with energy recovery.