A prototype green roof was constructed and monitored in Pittsburgh, Pennsylvania, to demonstrate a way to reduce storm water runoff and combined sewer overflow (CSO) events. The large impervious surface area created by urban development in Pittsburgh creates a wet weather flow that the existing combined waste waster and storm water sewer system cannot contend with. Green or vegetated roofs can reduce the amount of storm water that reaches the sewer conveyance system by replacing an otherwise impervious roof with porous soil that retains rainwater and plants that evapotranspire resulting in reduced storm water flows to the sewer system. The prototype green roof reduced the runoff volume by up to 70% compared to a conventionally ballasted roof covering a control portion of the same building. A reduction of at least 20% was found for rainfalls of 1.5 cm (0.60 inches) or less. The green roof also reduced the flow rate of runoff throughout storms. Peak values from the green roof were between 5% and 70% lower than control roof flow rates. For some small storms, the time of peak flow rate was delayed by up to several hours. In general, the green roof delayed the start of runoff and extended the time period of low residual flows that existed at the end of a storm. Water quality tests indicate that in most cases for the storms observed, a first-flush phenomenon was not evident in green roof runoff samples. Levels of phosphorus and chemical oxygen demand (COD) were elevated by the green roof. Both the control and green roofs produced runoff that demonstrated neutralization of slightly acidic rainfall.

The design and construction industries have an increasing interest in and responsibility for a building’s environmental effects over its entire life cycle. Quantification of all building phases is important in life-cycle assessments (LCAs), especially for the construction phase, which is often disregarded. This research uses an input-output-based LCA framework to create a more comprehensive estimate of the environmental effects of construction processes. The hybrid LCA model is based on Carnegie Mellon University’s Economic Input-Output Life Cycle Assessment (EIO-LCA) tool and combines a new EIO-LCA “hybrid” interface with updated and reformulated environmental effect vectors for EIO-LCA’s 13 construction sectors. Eight construction project case studies modeled on the input-output (I-O)-based hybrid LCA framework demonstrate the model’s broad applicability; gasoline, particulate matter, and global warming potential effects generally increased across all construction sectors and case studies. The I-O-based...

This research examined the environmental impacts due to the construction phase of commercial buildings. Previous building research has often overlooked the construction phase and focused on the material and use phases, discounting the significant environmental impacts of construction. The research was conducted using life-cycle assessment (LCA) methodology, which is a systematic environmental management tool that holistically analyzes and assesses the environmental impacts of a product or process. Life-cycle inventory results focused on particulate matter, global warming potential, SOx , NOx , CO, Pb, nonmethane volatile organic compounds, energy usage, and solid and liquid wastes. Results over the entire building life cycle indicate that construction, while not as significant as the use phase, is as important as other life-cycle stages. This research used augmented process-based hybrid LCA to model the construction phase; this modeling approach effectively combined process and input-output (IO) LCA. One ...

Life cycle assessments (LCAs) of buildings often use an operational lifetime of approximately 50 years, and have simplified descriptions of building operations and maintenance. The typical service life period is inappropriate for some materials given their exposure and use, and the simplified descriptions do not fully represent maintenance, repair and replacement cycles. Building service life prediction modelling is examined to improve the representation of service life in LCA and the evaluation of environmental impacts. A process is developed that incorporates service life, operational energy and LCA modelling which provides a means of examining the effects of materials and systems in building operation, maintenance, repair and replacement. This process advances the field of building LCA by representing a more complete and accurate building life cycle, and by highlighting the impact of building service life models on the LCA methodological assumptions. Nine building envelope combinations are modelled. Cumulative life cycle impact and life cycle impact per year are shown to be primarily dependent on predicted material longevity (i.e. the frequency of major replacement of the envelope systems, as well as the differences in the frequency and intensity of prescribed maintenance) and the environmental indicators analysed. Les analyses du cycle de vie (ACV) des bâtiments utilisent souvent une durée de vie opérationnelle d'environ 50 ans, et offrent une description simplifiée du fonctionnement et de la maintenance des bâtiments. La durée de vie utile type n'est pas adaptée à certains matériaux, compte tenu de leur exposition et de leur utilisation, et les descriptions simplifiées ne reflètent pas pleinement les cycles de maintenance, de réparation et de remplacement. La modélisation de la prévision de la durée de vie utile des bâtiments est examinée afin d'améliorer la prise en compte de la durée de vie utile dans l'analyse du cycle de vie et l'évaluation des incidences sur l'environnement. Il est élaboré un processus qui intègre la durée de vie utile, l'énergie opérationnelle et la modélisation de l'analyse du cycle de vie, et qui fournit un moyen d'examiner les effets des matériaux et des systèmes sur le fonctionnement, la maintenance, la réparation et le remplacement des bâtiments. Ce processus fait progresser le domaine des ACV des bâtiments en décrivant un cycle de vie des bâtiments plus complet et plus exact, et en mettant en évidence l'impact des modèles de durée de vie utile des bâtiments sur les hypothèses méthodologiques des ACV. Neuf combinaisons d'enveloppes de bâtiment sont modélisées. Il est montré que les impacts cumulatifs du cycle de vie et les impacts du cycle de vie par année dépendent essentiellement de la longévité prévue des matériaux (à savoir, de la fréquence des principaux remplacements des systèmes de l'enveloppe, ainsi que des différences quant à la fréquence et à l'intensité de la maintenance prévue) et des indicateurs environnementaux analysés. Mots clés: bâtiments, durabilité, analyse du cycle de vie (ACV), longévité, maintenance, prévision de la durée de vie utile, durée

Carbon dioxide (CO₂) emissions related to spectator’s transportation to collegiate football events is a significant consideration in the overall carbon footprint of collegiate sporting events. Transportation mode affects CO₂ emissions per spectator and stadium location, specifically on- and off-campus locations affect the transportation mode chosen by spectators. The quantity of CO₂ emissions generated from spectators’ transportation to collegiate sporting events at an on-campus university stadium is compared to off-campus stadium. The transportation modes and miles traveled by spectators were modeled with GREET 2016 to estimate CO₂ emissions. Significant differences were found between the two stadium locations regarding the spectators’ choice of transportation mode and distance traveled. Implications are presented for environmental sustainability and planning.