by Stephen Barrett – Whole Life Cycle Lead at Irish Green Building Council – A short version of this article has been published on The Hardware Journal News
The carbon profile of a small house
We now have a law in Ireland that requires us to cut our carbon emissions to 49% of what they were in 2018. Each bar in the chart shows the projected carbon emissions from a small new house every year of its life for an assumed 50 years.
The small repeating yellow bars are the emissions from heating, lighting and cooling every year – operational energy that makes up part of your annual bill. Current building regulations mean that we must build houses to a certain energy standard to limit costs for occupiers and emissions for the planet. The good news is that as the grid decarbonises, energy provision should be less impactful in the future so these yellow bars should reduce each year. We are looking at the future here and we can influence it. That being said, we should still strive to use as little as possible to avoid the need to create more and more infrastructure, because building infrastructure comes with its own environmental impacts.
Like infrastructure, building homes causes emissions too. The much larger, mainly blue bar at year zero before the house is inhabited, shows the emissions associated with manufacturing all its materials and components, bringing them to site and constructing the house. The production of hardware almost always produces greenhouse gases too.
In Ireland, as in most countries, there are few regulations on this, and unlike the yellow bars, we can not influence this in the future with a retrofit or a lower carbon grid. Those emissions happen now, and once they do they are in the atmosphere for the long term, so the chart should look more like image 2. You can see that materials manufacture before construction is roughly equal to the first 20 years of operating the building, or more if our grid decarbonises in future. Yet when we talk about low emissions homes we never talk about this carbon ‘embodied’ in the building.
The true impact of material choices
Greenhouse gas emissions are measured in grams, kilos or tonnes of carbon dioxide equivalent (gCO2e, kgCO2e, tCO2e), but that does not mean a lot to most people without context. So, for context, remember this – driving a modern car 1 kilometre will produce around 122gCO2e depending on the car*.
What does this have to do with buildings? Well, producing a single typical lightweight concrete block releases the same global warming emissions as driving 46km. If your work involves choosing materials and you want to do your bit to tackle climate change you should think about that. Producing one kilo of structural steel is equivalent to driving 26km and producing one kilo of aluminium is comparable to driving 108km.
A kilo of timber on the other hand requires emissions equivalent to 1.4km, but it will have sequestered 13.4km worth of carbon as it grew in the forest, giving an overall impact of -12km. Specifying timber instead of concrete or steel is one of the things you do to put the climate change car into reverse.
Another good example is insulation. It has been estimated that if Ireland is to build the homes it needs this decade, then we are going to need about 25 million cubic meters of insulation to ensure they are up to building regulations. Producing a single cubic meter of PIR produces the same CO2e as driving almost 1200km. EPS and bio-based wood fibre are better – around 785km each, but the bio-based will again have that sequestration bonus – 1,650km of carbon sequestration gives a net impact of -865km.
According to the World Green Building Council, globally, we have plans to build as much as a whole of New York City every month to. In Ireland, 400,000 new homes must be built by 2030 but currently, very few people are questioning where the materials for all this building will come from. Every specifier can make a difference and influence the market. Remember – think global, act local.
EPDs are like nutrition labels
If you were not aware of the above or have not thought about it yet you are not alone. The products we use today come to us neatly packaged in boxes or on pallets with only the performance information you need to know included – there is no requirement to tell you the environmental impact of production. It is impossible to look at two steel beams and know which contains recycled steel and which is all virgin material harvested at great energy cost. It is also hard to tell which was produced in a coal fired blast furnace and which came from an electric arc furnace running on renewable energy. The difference these kinds of details make to greenhouse gas emissions is huge yet remains invisible. Should that information be disclosed and attached to the product? It could be possible with a simple QR code, or even more simply, stamped on it.
If you had this information, you could make a more informed choice, and that is what influences markets. The manufacturer might change their production method to attract your custom. In the absence of this information being automatically supplied, the Irish Green Building Council (IGBC) recommends you ask manufacturers and suppliers for an EPD.
EPDs are Environmental Product Declarations, documents that are created by carrying out a Life Cycle Analysis of a product. Put simply, they tell you the environmental impact of producing that concrete block, PIR or anything else. Think of the nutrition labelling of food – the EPD is similar, but the information refers to the effect on the environment rather than the effect on you. It would be useful if at least some of the data from EPDs were printed on the packaging to help informed choice.
There is no requirement to produce an EPD, but many companies choose to do so in order to demonstrate their commitment to the green agenda and to differentiate themselves in the marketplace. There are extra credits available for buildings that use materials with EPDs in certification schemes such as LEED, BREEAM and Ireland’s Home Performance Index, so in some cases at least, there is a reward for specifiers choosing them.
Traffic lights work
You may already be familiar with Building Energy Rating (BER) certificates and how they indicate the efficiency performance of a building in use.
A voluntary organisation in the UK, the London Energy Transformation Initiative, has developed a similar certificate for quickly understanding the embodied carbon impact of a building. It demonstrates the emissions that occurred to produce each square meter of the building. In order to calculate this, a design team must use the data in EPDs, to sum up the emissions of the production of all the materials required and divide the total by the number of square meters. Currently, this is not a simple task and it is not transparent. If each material carried data from its EPD on its packaging the market could make better informed choice. This would encourage manufacturers to improve production processes in order to win business and move the market. The scale and impact of our building practices mean this could make a significant contribution to reducing our spiralling greenhouse gas emissions.
Where do I find out more about EPDs?
If you are a manufacturer in Ireland you can begin your EPD journey at EPDIreland.org. EPD Ireland is the national programme for helping manufacturers produce EPDs. Operated by the Irish Green Building Council, it can guide manufacturers through the process and advise on finance available from Enterprise Ireland to support the costs.
If you are a manufacturer outside Ireland, take a look at www.eco-platform.org/the-eco-epd-programs to find a programme suitable for you.
If you are a stockist we encourage you to ask manufacturers to supply EPDs so your customers can make better-informed choices. Ultimately, all markets respond to the demands of clients. Until we see greater regulation, demand will influence supply.
*Using the 2021 WLTP measurement figure at https://www.seai.ie/data-and-insights/seai-statistics/key-statistics/transport/