Understanding embodied carbon in flooring is vital, as government projects increasingly
demand low-carbon materials and transparent sustainability data, says Richard Aylen

The extent to which a product or material affects global warming is usually measured by the amount of carbon dioxide or other ‘greenhouse gases’ that are generated during its lifetime.

For many years the construction industry has been looking into how it can reduce its effect upon global warming. This has included looking at waste reduction, designing energy efficient buildings and using materials that are sustainable and carbon neutral.

We use phrases such as ‘net zero carbon’ and ‘carbon neutral’, so before we go further let’s look at what these actually mean.

Here is a useful definition of both carbon neutral and net zero as supplied by the Natural History Museum in London:

A person, company or country is carbon neutral if they balance the carbon dioxide they release into the atmosphere through their everyday activities with the amount they absorb or remove from the atmosphere. This is also called net zero carbon emissions or net zero carbon, because overall no carbon dioxide is added to the atmosphere.

The definition of net zero emissions is sometimes expanded to include other gases such as methane, nitrous oxide and hydrofluorocarbons. This is sometimes referred to as net zero greenhouse gas emissions or simply net zero. These other gases contribute about 24% of global greenhouse gas emissions and carbon dioxide the remaining 76%.

‘What does carbon neutral mean and what is net zero?’
So, we can see these definitions can be used in a general way to sum up the effect a product or material has on global warming.

But when we talk about the carbon generated by or contained within the body a product we usually talk about embodied carbon.

Broadly speaking, as far as construction is concerned there are two main types of carbon. The first is ‘operational carbon’, which arises after the building has been completed. This includes carbon emissions from using gas and electricity and is one of the main reasons we are switching to renewable energy sources such as solar and wind generated power.

This category is of interest to, among others, manufacturers of heating and cooling equipment but also includes thermal insulation and carbon arising from maintenance and other activities associated with operating the building.

In recent years there have been significant gains in reducing operational carbon through use of renewable energy, increasingly efficient building operating systems and use of thermal insulation.

As the opportunities for further reducing operational carbon are diminishing, increasing attention is being directed at finding additional ways of reducing global warming. For the construction industry this means an increasing focus upon embodied carbon.

Embodied carbon is of most interest to us in the flooring industry. The amount of embodied carbon contained in the product or material is used to measure the greenhouse gas emissions that occur when construction products are manufactured, transported, installed, replaced and disposed of at the time of demolition.

The amount of greenhouse gas generated by the product is directly proportional to its effect upon global warming.

So why should a flooring manufacturer or contractor need to know about embodied carbon?

If you’re a flooring manufacturer or installer who is in a position to influence the flooring specification for a project, then having an understanding of embodied carbon and how this relates to your products will be very useful. This is particularly so if you work on government projects or for larger organisations because these institutions are leading the way in low carbon construction.

If you’re recommending flooring products to the designer or main contractor, it is increasingly likely that you will be asked to provide embodied carbon data. If you don’t understand this issue the likelihood of your proposals being rejected is greater.

For a long time now many of the UK’s larger main contractors have been using carbon measurement tools to calculate the total amount of embodied carbon for their designs. Until now it was almost unheard of for a client to use benchmarks for embodied carbon, but this is changing.

In Scotland the Scottish Futures funding scheme for school building includes an upper limit for embodied carbon of 600kg per square metre. Projects that don’t comply with this won’t receive funding.

Later this year, in its 2025 Output Specification for new school buildings, England’s Department for Education (DfE) will impose a maximum limit of 550kg of embodied carbon per square metre of floor area for new school buildings (in fact, in practice it uses ‘carbon equivalent’ in order to include a defined list of greenhouse gases, as mentioned by the Natural History Museum in the quotation above).

These measurements include all elements of the building of course, but flooring systems will play their part. In practice, using as many low carbon materials as possible will give designers more latitude to use higher carbon materials for parts of the building where low carbon materials may not yet exist.

At the same time the DfE is setting limits for ‘biogenic carbon’. This is carbon that is locked up in the fabric of the material by biological processes. Perhaps the best illustration of this is the way that trees collect carbon as they grow. Carbon is stored in the wood itself until such time as the wood is finally burned or it decomposes.

By reducing the amount of carbon in the atmosphere trees help to reduce global warming whilst the timber remains in use. In respect of flooring, if you have a solid wooden floor with a very long lifespan you will be ‘locking up’ carbon for the life of the floor, thereby reducing global warming.

This cycle of carbon collection (also known as sequestration) and release over the life cycle of the product does not increase the overall amount of carbon in the environment and so this is why timber is often referred to as a ‘carbon neutral’ material.

For building design, products with high levels of biogenic carbon are seen as a sustainable option, and this is why timber features strongly in low carbon buildings. This is not to be confused with the way that carbon is bound up in plastics and other crude oil derived materials, as used in many textile and synthetic floorcoverings.

This category of carbon ultimately increases global warming because when crude oil-derived floors are disposed of carbon is released into the atmosphere that would otherwise have remained locked underground, resulting in net increases in carbon, and consequently, increases in global warming.

As a flooring contractor or manufacturer, you may ask how you can find out what levels of embodied carbon are contained in a product. For designers there are various carbon assessment tools that can be used to calculate the carbon levels for the whole project but the building blocks for these tools usually take the form of environmental product declarations (EPDs).

An EPD is an assessment of a product or material’s effect upon global warming. The whole life span of the product is usually assessed, from when it exists as raw materials, through manufacture, transportation and installation to when it is finally disposed of. Credit is also given where there is potential for recycling or repurposing.

This last factor is one which makes solid hardwood floors attractive to sustainable building designers because they can be refurbished many times over and have a very long service life.

Anyone who follows trends in construction will know that there is a strong focus on refurbishment and adaptation of existing buildings in place of new build. The way we look at embodied carbon is really the driving force behind this. If you consider that the majority of the embodied carbon in a building is contained in the main structure and foundations, it doesn’t really make sense to demolish and dispose of the existing structural elements only to replace them with new ones.

If you do this, you’re releasing the embodied carbon from the old building (bad for global warming!) and then replacing it with new concrete and steel which includes yet more embodied carbon. There can be cost implications with reusing old buildings but in terms of sustainability it is often the obvious choice. When you factor in waste processing and disposal though, the price gap narrows somewhat.

At the present time we are seeing strong trends towards measurement of carbon for both new build and refurbishment projects and as is often the case the trailblazers are government departments and larger organisations.

It’s inevitable however that over time the same practices will filter down to smaller projects. For us in the flooring industry, if we keep abreast of this growing aspect of our industry, the information we can supply to our customers will be all the more relevant and beneficial.

www.junckers.co.uk
Richard Aylen is technical manager, Junckers