The construction industry is a major contributor to global greenhouse gas emissions. A recent United Nations report, Building Materials and The Climate: Constructing A New Future, highlights that the building and construction industry is by far the largest emitter of greenhouse gases, accounting for 37% of global emissions. To address this, many countries have committed to reducing their carbon footprints.
In 2015, 196 countries at the UN Climate Change Conference (COP21), committed to an international treaty (the Paris Agreement) to hold “the increase in the global average temperature to well below 2°C above pre-industrial levels” and “to limit the temperature increase to 1.5°C above pre-industrial levels.” Since 2020, countries have been submitting their national climate action plans, known as nationally determined contributions (NDCs). In their NDCs, countries communicate actions they will take to reduce their greenhouse gas emissions in order to reach the goals of the Paris Agreement. As a result, design professionals are increasingly responsible for minimising the environmental impact of buildings throughout their lifecycle. This involves selecting low-carbon materials, optimising building design and incorporating energy-efficient systems. By making informed decisions during the design phase, architects and engineers can significantly reduce a building’s carbon footprint and contribute to a more sustainable future.
Understanding carbon emissions classifications
Greenhouse gas emissions can be quantified and are classified as either ‘embodied’ or ‘operational’. The term embodied carbon emissions refers to emissions originating from the design, production and deployment of materials (before occupancy). Embodied carbon includes the emissions from extracting materials, manufacturing materials, transporting materials to the construction site, construction practices, maintaining the building, demolishing the building and transporting and recycling the waste. Embodied carbon is largely set before a building is built. In their article, Embodied Carbon 101: Building Materials: How to eliminate the emissions hidden in concrete, steel, insulation, and other building materials, authors Weir, Rempher and Esau explain how embodied carbon is calculated:
“Embodied carbon is calculated as global warming potential (GWP) and expressed in carbon dioxide equivalent units (CO2e). To quantify a product’s embodied carbon, an analysis called life cycle assessment (LCA) is used to assess the environmental impacts associated with each stage of the product lifecycle. The disclosure of LCA results through Environmental Product Declarations (EPDs) provides valuable information to consumers about the environmental impact of building products. EPDs are essentially material ‘nutrition labels’ that report a variety of life cycle impacts, including global warming potential, acidification, eutrophication, ozone depletion, and smog formation.”
Organisations like UL Solutions and the Building Research Establishment (BRE) are driving the development of standards and tools to assess the environmental impact of construction materials and products. Product Category Rules (PCRs) provide a standardised framework for conducting Life Cycle Assessments (LCAs) and publishing Environmental Product Declarations (EPDs). These PCRs are developed by UL through a collaborative process involving various stakeholders, including manufacturers, suppliers and environmental experts. By establishing clear guidelines for data collection, analysis and reporting, PCRs enable transparent and comparable assessments of product environmental performance. This information empowers designers, builders and owners to make informed decisions that minimise the environmental footprint of construction projects. PCRs are living documents subject to updates and most PCRs expire every five years. They must be reviewed at that time to address relevant changes in the industry. When no existing PCR aligns with a specific product or geographic region, UL collaborates with stakeholders to develop new PCRs or adapt existing ones to meet unique requirements.
Managing greenhouse gas emissions
Globally, the International Standards Organization (ISO), has developed a technical committee, ISO/TC 207/SC 7 Greenhouse gas and climate change management and related activities, to manage greenhouse gas emissions, as well as to adapt to the effects of climate change in support of sustainability. This committee has published 17 standards with an additional 11 in development.
Standards in the series that are particularly noteworthy include:
IWA 42 Net zero guidelines: provides guiding principles and recommendations to enable a common, global approach to achieving net zero greenhouse gas emissions through alignment of voluntary initiatives and adoption of standards, policies and national and international regulation.
ISO 14064 Greenhouse gases: contains three parts, and specifies principles and requirements at the organisation level for the quantification and reporting of greenhouse gas emissions and removal.
ISO 14065 General principles and requirements for bodies validating and verifying environmental information:specifies principles and requirements for bodies performing validation and verification of environmental information statements.
