Benchmark LCA e uso di EPD nei Green Building Rating System

Lo studio indaga l’utilizzo di valori soglia di riferimento (benchmark) relativi all’analisi Life Cycle Assessment (LCA) e all’uso di certificazioni EPD all’interno dei Green Building Rating Systems (GBRSs). La domanda di certificazioni inerenti alla sostenibilità ambientale in edilizia è in aumento, ma la non comparabilità dei risultati LCA dovuta alle differenti richieste dei sistemi multicriteri costituisce un problema. La scelta di includere nell’analisi LCA diverse parti dell’edificio e di adottare differenti confini di sistema porta ad un’inconfrontabilità delle valutazioni LCA. Lo studio mette in luce potenzialità e criticità dell’uso del Life Cycle Assessment e di EPD nei GBRSs, mostrando come un’uniformità delle scelte legate all’intero ciclo di vita e l’adozione di valori soglia comuni possa portare ad una confrontabilità delle informazioni ambientali degli edifici certificati

LCA benchmarks in building's environmental certification systems

The paper deals with the definition of reference values (benchmarks) referred to the Life Cycle Assessment (LCA) indicators used in the environmental certification systems of buildings (Green Building Rating Systems, energy-environmental certifications and environmental labels) highlighting their potentiality and criticality. The environmental certification systems more and more often consider the use of indicators based on LCA methodology which allow to draw attention to environmental performances of building in terms of impacts during the whole life cycle, from the raw materials extraction to the disposal. Today, the environmental impact measure obtained, could be interpreted through the comparison between similar solutions, due to the absence of thresholds which indicate the eco-efficiency of buildings: the benchmark applied to the LCA indicators becomes the threshold value through which measure the real environmental performance of the object analysed. It is a variable value because it depends on the evolution of technologies and construction practices. The environmental certification systems are the first ones which develop a process to define benchmarks because they have to assign a rating score to the indicators in order to obtain the certification. Through the analysis of principal certification systems, characterized by the use of LCA methodology within the score criteria, the different benchmarks methodologies (related to the LCA indicators) are identified and explained. Benchmarks are typically developed through linear interpolation systems, statistical analysis or the modelling of a reference building. In particular the analysis refers to the Green Building Rating Systems (GBRSs), such as DGNB, LEED, and BREEAM, and the energy-environmental certifications (Minergie-Eco). It is showed how the benchmark, into the certification systems, assumes different meanings: it could be the starting standard value (reference value), or the improvement value (target value) or the minimum value to obtain the certification. Starting from these differences and peculiarities, the paper demonstrates potentiality and criticality of the methodological approaches used, in order to understand the role of benchmark in the development of new policies and environmental strategies

Change management and new expertise in AEC firms: improvement in environmental competence

The aim of the paper is to provide an overview of the change management inherent Architecture, Engineering and Construction firms, focusing the attention on the transformation made by environmental issues and their related drivers. Over the last years, building sector has become increasingly complex, due to the heavy demand of a wide range of requirements and to the globalization of the market. This leads on one side the innovation of digital tools, as a result of the development of Information and Communication Technology – ICT, and on the other the division of labour in AEC firms, that is socially spread with an even more highly specialization. The fragmentation can take place in two directions: along what is conventionally defined as the vertical dimension of the process (i.e. the sequence of operations that proceed from inception to implementation phase) as well as along the horizontal dimension (i.e. operations occurring at any given stage). The paper shows the results of the analysis carried out on some of the AEC firms established at international level, highlighting the inner structure, organization, competences and tools used in practice. The configuration of the process structure and the consequent division of labour turn out to be established by a set of internal conditions, generated by the project itself as well as the available technology. Furthermore, the decision to structure internal firm hierarchies or to have external equipment (both experts and tools) depends on the cost that the firms should undertake in order to acquire knowledge, services or products that are external to their sphere of governance. The overview gives an evidence that the explosion of product/service options and the connected specialized systems for the whole building, from exterior cladding to computer-controlled HVAC, require even more a highly amount of knowledge and skills and the demand of new competences and expertise. In particular, the study shows the increasingly request in AEC firms of experts and tools, to deal with the challenging environmental topics. Firms themselves are taking advantage by the integration of environmental topics and goals, as proven by the fact that in the top ten global AEC firms seven of them are considered environmentally friendly (source: ENR). The paper highlights that many drivers are pushing effort in that direction: on one hand, policy and legislation at international and national level, incentive programs and also voluntary certification such as Green Building Rating System; and on the other hand design firms themselves, stimulated by competiveness or, in few case, by their philosophy

Nutrient availability and climate as the main determinants of the ratio of biomass to NPP in woody and non-woody forest compartments

Key message: Once the effect of stand age has been taken into account, nutrient availability and climate play a crucial role in determining the B:NPPs of woody and non-woody tissues. - Abstract: Forest ecosystems accumulate large amounts of carbon in living tissues. The residence time of this carbon in the ecosystem depends largely on the turnover time of these tissues, which can be estimated as a surrogate of the ratio of biomass to net primary production (B:NPP). We used a global forest database of 310 sites containing data for biomass stocks and NPP to investigate the differences of B:NPPs among species and forest compartments and to determine B:NPPs main exogenous (mainly climate and nutrient availability) and endogenous (leaf habit and stand age) drivers. We used asymptotic exponential functions to adjust the B:NPPs of woody compartments to a theoretical stationary state to allow comparisons between forests of different ages. The B:NPPs of woody tissues (branches, stems, and coarse roots) were positively influenced by stand age, conversely to fine roots and leaves, which were weakly dependent on the age of the forest. The B:NPPs of woody tissues were positively correlated with nutrient availability, whereas fine-root B:NPPs decreased with increasing nutrient availability. The foliar B:NPP of evergreen forests was positively correlated with water deficit, and the fine-root B:NPP was correlated positively with the seasonality of precipitation and with annual thermal amplitude but negatively with water deficit. Our results support the influence of climate on the B:NPPs of non-woody compartments and identify nutrient availability as the main influence on the B:NPPs of woody tissues

Valutazione LCA di edifici temporanei: il caso dei Cluster di Expo 2015

La vita molto breve degli edifici temporanei costruiti in relazione ai mega eventi impone di individuare strategie adeguate per la gestione del fine vita di tali strutture al termine dell’evento, al fine della riduzione degli impatti ambientali complessivi. Il testo presenta i risultati di una valutazione LCA svolta sugli edifici temporanei di Expo 2015, definiti Cluster. Sono stati valutati diversi scenari di fine vita (estensione d’uso in loco; ricollocazione; demolizione con riciclo e ricostruzione) al fine di definire le potenzialità di riduzione degli impatti ambientali nel caso di riuso. Per poter comparare gli scenari, la valutazione è stata svolta estendendo i confini di sistema alla seconda vita dell’edificio e dunque sviluppando una metodologia apposita per gli edifici temporanei

Twenty-Two Years of Warming, Fertilisation and Shading of Subarctic Heath Shrubs Promote Secondary Growth and Plasticity but Not Primary Growth

Most manipulation experiments simulating global change in tundra were short-term or did not measure plant growth directly. Here, we assessed the growth of three shrubs (Cassiope tetragona, Empetrum hermaphroditum and Betula nana) at a subarctic heath in Abisko (Northern Sweden) after 22 years of warming (passive greenhouses), fertilisation (nutrients addition) and shading (hessian fabric), and compare this to observations from the first decade of treatment. We assessed the growth rate of current-year leaves and apical stem (primary growth) and cambial growth (secondary growth), and integrated growth rates with morphological measurements and species coverage. Primary- and total growth of Cassiope and Empetrum were unaffected by manipulations, whereas growth was substantially reduced under fertilisation and shading (but not warming) for Betula. Overall, shrub height and length tended to increase under fertilisation and warming, whereas branching increased mostly in shaded Cassiope. Morphological changes were coupled to increased secondary growth under fertilisation. The species coverage showed a remarkable increase in graminoids in fertilised plots. Shrub response to fertilisation was positive in the short-term but changed over time, likely because of an increased competition with graminoids. More erected postures and large, canopies (requiring enhanced secondary growth for stem reinforcement) likely compensated for the increased light competition in Empetrum and Cassiope but did not avoid growth reduction in the shade intolerant Betula. The impact of warming and shading on shrub growth was more conservative. The lack of growth enhancement under warming suggests the absence of long-term acclimation for processes limiting biomass production. The lack of negative effects of shading on Cassiope was linked to morphological changes increasing the photosynthetic surface. Overall, tundra shrubs showed developmental plasticity over the longer term. However, such plasticity was associated clearly with growth rate trends only in fertilised plots

Simulating wood quality in forest management models

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