What is lifecycle assessment?

All products (or systems), including those used in construction, have some impact on the environment. This impact can occur from the point at which raw materials are extracted, through processing, manufacture, and then on into refurb, and ultimately disposal/recycling.

The embodied impacts of materials (especially carbon and water) are increasingly coming under scrutiny by consumers and society in general.

As a sector, construction is responsible for some of the biggest impacts on the environment – accounting for around half of all non-renewable resources consumed. No surprise then that, in recent years, the industry has faced pressure to play its part in delivering a low-carbon, more environmentally friendly, built environment.

With almost half of the UK’s carbon emissions coming from day-to-day use of the built environment (with heating both spaces and water accountable for a significant proportion) it’s not hard to see the potential for improvement and industry is rising to meet the challenge.

The digital data-driven revolution, with BIM at its heart, should make for smarter decisions by the project team, particularly at the time of specification, and provide a real understanding of the impacts of a building as it comes into use and is eventually decommissioned.

What is lifecycle assessment?

Lifecycle assessment refers to a methodology used to measure the impact of products (or systems), components or even whole buildings over a lifecycle. The assessment should include the energy and materials used and any resulting waste and pollutants.

What tools for lifecycle assessment are available?

A wide range of different methodologies, terms and standards, methodologies and protocols (both formally and informally) are emerging within the industry, often adapted from other sectors.

Tools for lifecycle assessment can be classified according to three levels (Haapio and Vitaniemi, 2008, Ortiz, Casteels et. al 2009).

• Level 1 takes in product comparison tools such as Umberto (Germany), or TEAM (France) which add together individual material and components to form a lifecycle assessment.
• Level 2 tools take in whole-building design or decision support tools such as eTool. These tools consider the building as a starting point of analysis and gradually work through the construction filling in details.
• Level 3 includes whole-building assessment frameworks such as BREEAM (UK) or LEED (USA). These tend to be comparative scoring systems that consider the entire product lifecycle and take in wider social sustainability issues. Critics suggest that context is currently missing (geographical location, for example, making a huge difference in impacts and performance).

There's no 'one size fits all' when it comes to lifecycle analysis - how much detail is required will inform the approach. The greater the detail, the trickier the task, but the better the output. In reality, most projects are likely to include a greater fidelity of data where it best informs decision-making and where it is more readily availability.

Which environmental impacts should be considered?

When thinking about environmental impacts there are many things to consider – the effects on air or water quality, the use and depletion of natural resources such as minerals or water, the amount of energy that needs to be expended, the toxic threat of pollution on land, sea and air, and its impacts on humans and the wider ecosystem, and the amount and type of waste generated requiring disposal.

The importance placed on these elements will change over time – where the focus in the 1970s and was arguably on reducing sulphur emissions to combat acid rain, and in the 1980s switched to the depletion of the Ozone Layer through use of CFCs found in aerosols, Today the focus is more generally on reducing carbon emissions to combat climate change with the ambition of driving efficiencies and reducing costs in the process.

What should the scope of the assessment be?

A lifecycle assessment can explore examine the environmental impacts throughout the entire lifecycle (from the extraction of raw materials to processing, manufacturer, refurb to end of life/disposal) or just part.

It’s important to be clear on scope from the outset - do you need to explore the lifecycle from ‘cradle to grave’ or ‘cradle to cradle’? At the very least the manufacture of a product (‘cradle to gate’) should be included and, more likely, transport to and installation on site. You need to be very clear as to whether your scope will only include what happens in the building, the entire plot or site or beyond (such as transportation and off-site manufacture). Obviously there are immense variations in impacts in these stages and significant unpredictability and, for these reasons, these can often be omitted from assessments.

You may wish to consider environmental impacts at a range of lifecycle stages:

• Extraction of resources – For some raw materials extraction will be the main environmental impact, for others the manufacture/refinement will play a more significant part.
• Manufacture – Significant amounts of energy are likely to be expended in the manufacturing process – this is particularly true when working with metals or cement.
• Packaging – Too little packaging and items get broken, increasing wastage. Too much is just a waste.
• Transportation – Transport impacts are likely to be slight, with global haulage opting for more efficient methods than just road transportation.
• Construction and site impacts (in particular site wastage)
• Maintenance / Refurbishment
• Demolition / Disposal

The construction industry generates significants amounts of waste across the project lifecycle - some of this total will be recycled or recovered but much will end up in landfill. By considering these issues at the start of a project better decisions can be made - making alternate choices or factoring in recycling from the outset.

What's essential for a robust assessment?

To be effective a lifecycle assessment should have a clear context, goal and scope. The chosen methodology should be made clear and transparency provided on the sources of data and any assumptions made. The study should clearly set out the range of environmental factors that will be assessed and the lifecycle stages that will be explored.

Impacts should include those required for a given process upstream (eg. Manufacturing windows) as well as those downstream such as waste disposal. Where comparisons are made they should be like for like. Where functionality is deemed more crucial that supreme eco-friendly credentials this should be made clear.

What about standards?

• ISO 14040 and ISO 14044 set out generic standards for the lifecycle assessment of products and services.
• ISO 14025 establishes generic environmental product declaration standards (EPDs) and EN 15804 sets out building product EPDs.
• EN 15978 provides guidance on whole of building/ whole of life lifecycle assessment. It provides a structure for the report (focussing on goal and scope definition, inventory analysis, impact assessment, and an interpretation of results).

Subsequent articles in this series will look at the practicalities of carrying out a lifecycle assessment and likely limitations.

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