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Embodied carbon constitutes a significant portion of a building’s greenhouse gas (GHG) emissions and is a key challenge for the construction and real estate sectors. Embodied carbon includes construction product manufacturing, building construction, material replacement and end of life. During the specification and procurement stage, designers and contractors have the opportunity to prioritize products with lower carbon footprints. Environmental product declarations (EPDs) are a growing source of environmental data in the construction products market, and are increasingly being used for (1) environmental performance assessment of buildings and (2) product comparison for procurement decisions during the later stages of building design. An obstacle to identifying and purchasing lower embodied carbon products is a lack of data quality and the transparency of EPDs. However, EPDs vary widely in their data quality and specificity, which can lead to inaccurate and misleading comparisons. A new method is presented to account quantitatively for estimates of variation in underlying data specificity in EPDs to enable fairer comparisons between EPDs and to motivate the reporting of actual variability and uncertainty in EPDs. The application of this approach can help purchasers to assess EPDs quantitatively. Practice relevance Life-cycle assessments (LCAs) and LCA data can be used within the construction sector to evaluate buildings and to assist in design, specification and procurement decision-making. A new method is presented to support the assessment of comparability of functionally equivalent materials and products during the specification and procurement stage. Given the known variation and lack of precision within EPDs, this method provides quantitative metrics that correlate to a qualitative interpretation of EPD precision. This method can be used by anyone who is using EPD data to make product comparisons at the specification and procurement stage: It provides more confidence in choosing low-carbon material or product options when comparing between functionally equivalent options. It can incentivize product manufacturers and LCA practitioners to improve data quality and transparently report known variation in their EPDs. It may also motivate manufacturers to reduce GHGs from their products and processes.

Purpose The purpose of this paper is to present an analysis of common parameters in existing tools that provide guidance to carry out Whole Building Life Cycle Assessment (WBLCA) and proposes a new taxonomy, a catalogue of parameters, for the definition of the goal and scope (G&S) in WBLCA., Design/methodology/approach A content analysis approach is used to identify, code and analyze parameters in existing WBLCA tools. Finally, a catalogue of parameters is organized into a new taxonomy., Findings In total, 650 distinct parameter names related to the definition of G&S from 16 WBLCAs tools available in North America, Europe and Australia are identified. Building on the analysis of existing taxonomies, a new taxonomy of 54 parameters is proposed in order to describe the G&S of WBLCA., Research limitations/implications The analysis of parameters in WBLCA tools does not include Green Building Rating Systems and is only limited to tools available in English., Practical implications This research is crucial in life cycle assessment (LCA) method harmonization and to serve as a stepping stone to the identification and categorization of parameters that could contribute to WBLCA comparison necessary to meet current global carbon goals., Social implications The proposed taxonomy enables architecture, engineering and construction practitioners to contribute to current WBLCA practice., Originality/value A study of common parameters in existing tools contributes to identifying the type of data that is required to describe buildings and contribute to build a standardized framework for LCA reporting, which would facilitate consistency across future studies and can serve as a checklist for practitioners when conducting the G&S stage of WBLCA.

Environmental impact studies within the built environment rely on predicting building lifespan to describe the period of occupation and operation. Most life cycle assessments (LCAs) are ba...

In studying the environmental impacts of buildings, earthquake hazards are rarely considered, but their environmental impacts can be significant. This case study paper demonstrates how the ...

In evaluating the life cycle environmental impacts of buildings, the contributions of seismic damage are rarely considered. In order to enable a more comprehensive assessment of a building's environmental impact by accounting for seismic events, this project developed an environmental impact database of building component seismic damage – the largest of its kind known to date – by combining data from Carnegie Mellon University's Economic Input-Output Life Cycle Analysis (LCA) database with cost estimates of repair previously developed for FEMA's Performance Assessment Calculation Tool (PACT), a software that models probabilistic seismic damage in buildings. Fifteen indicators of environmental impacts were calculated for the repair of approximately 800 building components for up to five levels of seismic damage, capturing ‘embodied’ impacts related to cradle-to-gate manufacturing of building materials, products, and equipment. Analysis of the data revealed that non-structural and architectural finishes often dominated the environmental impacts of seismic damage per dollar spent in repair. A statistical analysis was performed on the data using Principal Component Analysis, confirming that embodied carbon, a popular metric for evaluating environmental impacts in building LCAs, is a suitable proxy for other relevant environmental impact metrics when assessing the impact of repairing earthquake damage of buildings.

This chapter reviews the efforts in North America on assessing and lowering the embodied carbon in buildings. The Intergovernmental Panel on Climate Change warns that the building sector needs to be zero carbon by 2050. While initiatives such as the American Institute of Architects 2030 Commitment have incentivized the reduction of operational impacts related to the use of buildings, new initiatives such as the Structural Engineers 2050 Commitment emphasize the reduction of embodied impacts related to material extraction, production, transportation to the site, construction, maintenance, and demolition. To assess and lower these impacts, three challenges arise in North America: the inconsistency in available databases and tools, the difficulty of including embodied carbon credits in rating schemes, and the scarcity of benchmarks. First, we review life cycle assessment databases and environmental product declarations available in North America. Then, we present the challenges of life cycle assessment in the Leadership in Energy and Environmental Design (LEED) rating scheme. Finally, the authors propose two benchmarking paradigms initiated in the USA to create a baseline for the embodied carbon of buildings, expressed in carbon dioxide-equivalent emissions normalized by floor area (kgCO2e/m2).

In this study, the cradle-to-gate environmental impact of a hybrid, mid-rise, cross-laminated timber (CLT) commercial building is evaluated and compared to that of a reinforced concrete building with similar functional characteristics. This study evaluates the embodied emissions and energy associated with building materials, manufacturing, and construction. Two alternative designs are considered for fire protection in the hybrid CLT building: 1) a ‘fireproofing design’, where gypsum wallboard is applied to the structural wood; and 2) a ‘charring design’, where two extra layers of CLT are added to the panel. The life cycle environmental impacts are assessed using TRACI 2.1 and the total primary energy is evaluated using the Cumulative Energy Demand impact method. Results show that an average of 26.5% reduction in the global warming potential is achieved in the hybrid CLT building compared to the concrete building, excluding biogenic carbon emissions. Except ozone depletion, where the difference in impact between scenarios is

Heating, Ventilation and Air Conditioning (HVAC) systems contribute significantly to operational energy and CO2e emissions during the service life of office buildings. Over the last decade, stringent energy codes have enabled the introduction of new HVAC technologies to reduce operational CO2e emissions. However, life cycle carbon emissions of buildings are odivided into operational carbon (OC) and embodied carbon (EC). Operational carbon are the CO2e emissions generated from the burning of fossil fuels used to heat, cool and power the building space during its service life, while EC encompasses the CO2e emissions equivalent to producing, procuring, installing, mantaining, repairing and disposing of the materials and components that make up the building. Over the last decade, broad efforts have improved the understanding of the role that HVAC system selection play in overall OC, nevertheless, EC of HVAC has remained unexamined This paper aims to identify typical HVAC systems used in office building design in Washington State and explore the effects of current practice on total energy use, operational and embodied CO2e. The study sample is composed of twenty office buildings in Washington State registered under the LEED v3 2009 version, from which 15 have obtained LEED certification in the last two years. The projects are registered under the New Construction (NC), Core and Shell (CS), Existing Buildings and Operation and Maintenance (EB:OM) and Commercial Interiors (CI) products and comply with the requirements established in the ASHRAE 90.1-2007 energy standard. The results show that typical HVAC system selection is often a combination of different technologies for ventilation, heating and cooling, and that in general: smaller buildings tend to incorporate high efficiency packaged units while medium and large size buildings typically rely on High Performance Variable Air Volume (HPVAV) systems or hydronic systems such as chilled beams and water source heat pumps (WSHP). The results also indicate that data available through the LEED v3 2009 documentation system on embodied carbon of the mechanical systems is limited and that simplified methods to assess embodied carbon of HVAC are needed in order to integrate EC into whole life assessment of Mechanical Systems.

Research and Practice Environmental Life Cycle Assessment (LCA) can be used to evaluate the environmental impacts of a building resulting from manufacturing, construction, operation and maintenance and the end of life demolition and disposal/re-use. Tracking impacts such as greenhouse gas emissions and smog formation, LCA can enable comparison of building proposals testing options of material use, system selection and system performance.

When structural engineering is taught as a design discipline, engineering and architecture students can understand the open-ended potential of structural engineering solutions and gain a better understanding of the opportunities for structure to shape and reinforce architectural concepts. By formalizing the iterative aspect of design processes common in architecture design studios, structural engineering courses can integrate design without requiring a radical configuration of the conventional lecture class structure. This paper outlines models that include design and analysis iterations in structures lecture courses. Developed for undergraduate and graduate architecture students, this model could be applied to engineering education as well. Student work from these exercises demonstrates integration of architecture and structural engineering. Three examples of iterations are presented to highlight a range of applications, including (1) iteration of method of spanning (e.g., truss, arch, and cable ...

Greenhouse gas emissions from extracting and manufacturing building materials, often termed “embodied carbon,” are produced before buildings are occupied and are more critical to meeting global climate targets than commonly assumed. In order to motivate reductions in embodied carbon, we need better data and established benchmarks. Although Life Cycle Assessment (LCA) methods have been used to analyze individual buildings, there has not been an agreed-upon understanding of the order magnitude and range of variation of the embodied carbon of buildings. In order to ad- dress this knowledge gap, the largest known database of building embodied carbon was compiled, normalized, and analyzed. In addition to establishing the range of embodied carbon values, this research identi ed sources of uncertainty and proposed strategies to advance embodied carbon benchmarking practice.