With nearly Zero Energy Building standards on the way, Pat Barry examines life-cycle assessment and embodied carbon calculation, its importance for buildings and infrastructure and how to minimise carbon emissions at the construction stage

Buildings have an impact on the environment at all stages of their lifecycle. Materials have to be quarried, mined or harvested, transported to factories and manufactured. The final products have to be transported to site, lifted into place and fixed in position. The buildings have to be operated, heated and cooled.

Over a 60-year life-cycle, components fail, roofs leak and need replacement, finishes spoil and need repainting and replacement. Eventually, the building ceases to provide its function and needs to be demolished and all its components disposed. Depending on the materials used or how they were put together, this will be by landfill, incineration, recycling or direct reuse.

To date we have only focused on one life stage, namely of the energy and carbon needed to operate heat and light the building. This made sense because this was the life-cycle stage with the biggest impact and it was possible to ignore the rest as inconsequential.

Nearly Zero Energy Buildings

However, this needs to change. The nearly Zero Energy Building (NZEB) standard is just over a year away for the public sector and a little more for the private sector. With operational energy cut to a minimum, the other life stages swim into focus. The embodied impacts involved in the construction of buildings are simply too important to be brushed under the carpet.

A study by Dr Jamie Goggins of NUI Galway in 2012 suggested that embodied carbon accounted for approximately 34% of regulated energy in a semi-detached house in Ireland. A study by embodied carbon experts Sturgiss Associates in a UK study, also from 2012, suggested that for offices it could be as high as 45%. All this before NZEB.

Many commercial buildings from the 1960s and 1970s are now reaching the perceived end of life cycle. Often the justification for the demolition of a building is that a modern replacement can reduce the operational energy and carbon of the building and offset the environmental impacts of building anew instead of renovating the existing. However, very few professionals check whether that is actually the case.

In new buildings and infrastructure, it is important to be aware of the impact of certain design decisions on the embodied carbon and other impacts. Certain design concepts may have far greater impacts than others so important to compare at the right time.

The shape of the building, the column spacings and structural beam depts all have major impacts on material use. What is the environmental impact of replacing concrete with, say, an alternative such as steel or cross-laminated timber? Unless the project engineer or architect can measure or at least be aware of the impact of certain design decisions, then opportunities may be lost to optimise carbon over the building life-cycle.

Life-cycle assessment (LCA) is now moving into the mainstream. There are European standards such as EN 15978, which set out how building level life cycle assessment should be calculated. Since late 2016, LEED V4 and BREEAM have credits for carrying out building-level LCA. The European commission has just released Level(s) a new reporting framework for integration into Green Public Procurement. This aims to standardise indicators for sustainable construction across Europe and LCA is one of the key indicators.

IGBC’s Home Performance index

The Irish Green Bulding Council’s (IGBC’s) own Home Performance Index, which is seeing rapid uptake from new home developers, includes LCA. Transport Infrastructure Ireland is releasing an assessment tool that requires embodied carbon calculation for road and rail. This means that 2018 will be the year that LCA really hits professional offices.

However, do we have sufficient data, tools and skills? This is one major gap in Ireland. IGBC has been working on a business plan since 2015 to bring LCA and embodied carbon calculation to the professional masses.

One thing we need is much more data for the impact of the products that we are using to construct the building. To do this, IGBC has now developed an Environmental Product Declaration (EPD) programme with the support of the Environmental Protection Agency’s Green Enterprise programme. This will allow Irish manufacturers to create, have verified and publish the environmental impacts of their construction products.

The Irish programme sets out mandatory indicators that must be assessed including global warming, ozone depletion, acidification of land and water, eutrophication, photochemical ozone creation, depletion of abiotic resources (elements) and depletion of abiotic resources (fossil). All of this is fully in line with international practice, meaning the EPD will be recognised and accepted across Europe.

Many manufacturers have already developed EPD under international programmes. They can now make these visible by uploading to IGBC’s new EPD Ireland platform www.epdireland.org.

Already, there is a full range of products in the EPD Ireland platform ranging from insulation to paints. Most of these are for imported products and have published through programmes such as the Institut Bauen und Umwelt eV in Germany or the Building Research Establishment in the UK. However, we need native manufacturers to start measuring the impacts of their products, as these are often the local bulky products with the most impact in a building.

The next step is to aggregate all of this into a national environmental database, which will include generic data for common materials where product-specific data is missing. The final step is to aggregate this data into easy-to-use tools for building-level LCA.

Software to calculate full LCA

It was important for IGBC to offer a simple solution to the market rather than just talking about LCA. The Irish Green Building Council has now teamed up with the leading Finnish LCA experts Bionova to allow building professionals to quickly calculate the LCA of a building through their One Click LCA software.

The web-based One Click LCA, which now has a customised offering for Ireland and particularly for the Home Performance Index, takes all the legwork out of calculating a full LCA to the European standard EN 15978. This reduces the time to a matter of hours rather than weeks and is now more akin to working out a Building Energy Rating. It draws on established European databases of construction products until such time as we have established a full national database.

However, LCA calculation is alien to most Irish professionals so the aim is to get training and accredited courses into the market. IGBC has arranged so that education providers in the universities and institutes of technology will be provided with free licenses for One Click LCA so that LCA can be integrated into undergraduate and post-graduate courses.

The intention is to make life-cycle carbon calculation part of the education process. Then we can start integrating it into every design office in the land. IGBC is currently offers one-day training in LCA. Most educated building professionals are aware of benchmarks for operational energy use through the Building Energy Rating or Passivhaus, but can we get to this level of embodied carbon literacy?

Finally, in order to move to a real circular economy, we need to consider what happens at the end of life of the building. If buildings are conceived as materials banks, we need to change the approach to what we put into building and how we assemble them. How easy is it to separate out the different components and reuse them?

A simple example is a high value hardwood floor. In a commercial refurbishment, this might have a very short life and become a victim of fashion. Can it be simply unclipped and resold for resuse for more or less the same value, or must it be prised up and broken and sent for incineration. If materials are laminated together, making separation impossible or are contaminated with toxic coatings, they have less potential for recovery.

Pat Barry is the CEO of the Irish Green Building Council, which he co-founded in 2010. He is an architect with over 20 years of experience in Ireland, Europe and South America. Barry holds a master’s degree in environmental design of buildings from University of Cardiff and he is a qualified Passivhaus and DGNB consultant.

For more information on EPD Ireland: www.epdireland.org
For more information on the Carbon Heroes Benchmark Program https://www.oneclicklca.com/construction/carbonheroes/
For more information on IGBC events and education: www.igbc.ie
For more on the Home Performance Index: www.homeperformanceindex.ie

http://www.engineersjournal.ie/wp-content/uploads/2018/01/Environmental-product-declarations-1024x683.jpghttp://www.engineersjournal.ie/wp-content/uploads/2018/01/Environmental-product-declarations-300x300.jpgDavid O'RiordanCivilconstruction,energy,housing
Buildings have an impact on the environment at all stages of their lifecycle. Materials have to be quarried, mined or harvested, transported to factories and manufactured. The final products have to be transported to site, lifted into place and fixed in position. The buildings have to be operated, heated...