In the realm of construction, understanding the environmental performance of a project is critical. The BS EN 15978:2011 is the current UK standard for conducting Whole Life Carbon (WLC) assessments, providing key guidance, procedures, and calculations for these evaluations. This article will take a deep dive into the core elements of this methodology, offering a comprehensive understanding of its significance, implementation, and implications for the future of sustainable construction.

Part 1: Introduction to BS EN 15978:2011

Subsection 1: The Importance of Environmental Performance Assessment

In today’s world, where climate change is a pressing concern, the need to minimise the environmental impact of construction projects is more critical than ever. The construction sector plays a significant role in the UK’s carbon emissions, contributing to nearly 40% of the total. Therefore, assessing and reducing the carbon footprint of buildings is a priority.

Subsection 2: The Role of BS EN 15978:2011

The BS EN 15978:2011 standard provides a framework for conducting a WLC assessment, a comprehensive evaluation of all building-related emissions over a structure’s entire life. This assessment covers operational carbon emissions from day-to-day energy use and embodied carbon emissions from material sourcing, component fabrication, transport, construction, maintenance, repair, replacement, demolition, dismantling, and disposal.

Part 2: Understanding the BS EN 15978:2011 Methodology

Subsection 1: The Life Cycle Stages

The BS EN 15978:2011 standard divides the life cycle of a building into four principal modules: Module A (Product sourcing and construction stages), Module B (Use stage), Module C (End of life stage), and Module D (Benefits and loads beyond the system boundary). Each module encompasses various stages and elements, providing a detailed framework for the assessment.

Subsection 2: Module A – Product Sourcing and Construction Stages

Module A focuses on reducing carbon emissions from the sourcing, transportation, fabrication, and construction of all materials and products. This module also underscores the need to understand the supply chain to ensure that the choices made will help reduce future carbon emissions.

Subsection 3: Module B – Use Stage

Module B aims to understand how the building will perform post-construction and how to minimise in-use emissions. This module includes the in-use emissions of some products and materials that can absorb carbon dioxide from the atmosphere over the building’s life cycle.

Subsection 4: Module C – End of Life Stage

Module C captures the emissions from when the building has reached the end of its useful life, covering deconstruction and demolition, transport, waste processing for reuse, recovery or recycling, and disposal.

Subsection 5: Module D – Benefits and Loads Beyond the System Boundary

Module D considers the potential future scenarios of the building after it has been dismantled or demolished. Its objective is to facilitate future reuse, recovery, and recycling at the highest possible level.

Part 3: Implementing the BS EN 15978:2011 Standard in Construction Projects

Subsection 1: The Role of Life Cycle Assessment (LCA)

Life Cycle Assessment (LCA) is a critical element in implementing the BS EN 15978:2011 standard. It provides a future projection of the carbon cost of anticipated day-to-day energy use, maintenance cycles, repair and replacement cycles, and final demolition.

Subsection 2: The Importance of Environmental Product Declarations (EPDs)

Environmental Product Declarations (EPDs) are essential tools for estimating emissions. They provide valuable information about the environmental impact of a product or material, offering insights into the carbon footprint of different construction components.

Subsection 3: The Alignment of Carbon Cost and Financial Cost

Interestingly, the reduction of carbon cost often aligns with the reduction of financial cost. Efficient use of resources can lower both the carbon emissions and the total cost of ownership of a building.

Part 4: Actions to Reduce the Whole Life Carbon Footprint

Subsection 1: Retrofitting

Retrofitting or reusing an existing building is typically the lowest carbon option. It has a significant embodied carbon benefit due to the existing structure and materials already on site.

Subsection 2: Using Recycled Materials and Content

Using recycled materials can reduce the carbon emissions from constructing a new building. Many standard products already include a degree of recycled content, which can help reduce the carbon footprint.

Subsection 3: Material Selection

The sourcing of materials and the fabrication of products are the largest contributors to embodied carbon emissions over the life of a building. Therefore, careful material selection is crucial in reducing carbon emissions.

Subsection 4: Operational Emissions from Day-to-Day Energy Use

A fabric-first approach, where the building’s envelope is designed to minimise heating and cooling requirements, can have long-term carbon emissions benefits.

Part 5: The Impact of the BS EN 15978:2011 Standard

Subsection 1: Increasing Adoption

Since the publication of the BS EN 15978:2011 standard, numerous organisations have embedded its guidance into their practices. This standard is now being used to mitigate carbon impacts in major infrastructure projects.

Subsection 2: Future Requirements

The Greater London Authority’s London Plan is being updated to require all referable schemes to carry out a detailed WLC assessment in accordance with the BS EN 15978:2011 standard. This will likely influence other UK local authorities to follow suit.

Subsection 3: Future Proofing Buildings

For buildings currently on the drawing board, future proofing the asset value with a WLC assessment and resulting actions to reduce its whole life carbon footprint is critical.

In conclusion, the BS EN 15978:2011 standard offers a comprehensive framework for assessing the environmental performance of buildings. By implementing this methodology, the construction sector can make significant strides towards reducing carbon emissions and promoting sustainable practices. As the world grapples with the challenges of climate change, such standards play a vital role in paving the path towards a more sustainable future.