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What is an EPD?

5 minutes
May 20th, 2021

Have you ever wondered how to measure the environmental impact of a building? In this blog we will be talking about all things EPD’s and why you should consider them when designing your next project.

What is an EPD?

An environmental product declaration (EPD) is an independent framework commonly used for construction-based products to help consumers understand a manufacturers environmental impact. This rating system takes into account data regarding products and their lifecycle in order to measure its environmental footprint during each stage of the production and disposal process. The goal of this framework is to support the consumer in their decision making when choosing building materials.

How is an EPD measured?

An EPD measures a product’s impact on the environment throughout its entire lifecycle – from cradle to grave. This is made up of several environmental impact indicators such as:

  • Global Warming
  • Ozone Depletion
  • Acid Rain
  • Algal Blooms
  • Smog
  • Energy Use
  • Water Consumption

An EPD quantifies this data to create numeric values for each product and its lifecycle stages, simplifying the consumers comparison and decision-making process.

How do we understand an EPD?

Below is a simple diagram illustrating the lifecycle of hardwood glulam. The numbers labelled in green are referred to as credits which are impacts avoided in the next product system, while numbers labelled in grey are considered environmental impacts. These figures derived from the Environmental Product Declaration for Hardwood Glue Laminated Timber and are measured as the amount of CO2 per m3 of hardwood glue-laminated timber.

From this diagram we can see that in its early stages, hardwood glulam is given a credit – this is due to the carbon stored in its wood fibres that is not released until timber decomposes. As the timber eventually goes through the product lifecycle, environmental impacts are added to this figure.

This diagram is based off the Environmental Product Declaration for Hardwood Glue Laminated Timber. See link for full details –

Here's a few reasons why we should consider a manufacturer's EPD:

  1. By examining a product’s EPD, you can make the right decision when it comes to choosing products. EPD’s are helpful during the design stage as they give you the ability to understand the processes used to create a product as well as the environmental impacts and outputs that come along with it. This means you can have confidence that the products you choose align with your values and makes an impact when it comes to reducing your environmental footprint.
  2. An EPD shows that a manufacturer is responsible for their environmental impact. Although EPD’s are gaining popularity, manufacturers can choose to share this data, emphasising a business’ transparency and commitment to sustainability. As well as this, those that do measure this data are constantly trying to improve their environmental impact. Manufacturers or industries often use this data as a benchmark to improve operations – such as boosting recovery rates, reducing energy use and increasing renewable energy sources.
  3. Having a framework means that data is verified and comparable. EPD’s are a trustworthy way of comparing the environmental performance of different products and materials. By comparing data using functional equivalent (opposed to weight as 1kg of steel does not have the same functional ability as 1kg of timber), you can ensure you are choosing the best possible product for your design and build.
  4. EPD’s are useful tools in gaining additional GBCA (Green Building Council of Australia) credits, increasing the potential for a Green Star rating. A Green Star rating is an independent assessment addressing the sustainability performance of a building. This certification is given to those who reach a specific sustainability level in a variety of categories relating to environmental impacts. The long term results of having a Green Star rated building can be – reduced electricity and water consumption, reduced greenhouse gas emissions and a competitive edge within the market.

Why should we choose timber over other structural materials?

From the glulam hardwood diagram above, we can see that even after the entire production process – this includes forestry, transportation, drying, processing and packing – timber is a sustainable material to use.

Carbon Storage – When compared to its counterparts, timber has a strong advantage due to its ability to store and lock carbon throughout its lifecycle. Growing trees absorb carbon dioxide from the atmosphere, emit oxygen and act as long-term carbon storage. This carbon remains locked in the timber until it burns or rots, therefore the timber that we use for building and construction can store carbon for life.

Embodied Energy – Embodied energy refers to the energy used when making the materials required for the construction of a building. Choosing materials such as timber and avoiding high fossil fuel alternatives can drastically change the amount of embodied carbon that is produced from a building, lowering the overall environmental footprint of the build.

The Timber Industry’s Circular Economy – Instead of making, using and disposing of materials, we can choose products from circular economies – when manufacturers reuse and recycle as much as they possibly can, creating a circular loop. The Australian Timber Industry is known to have one of the best circular economies as laws ensure that forested trees are replaced. This means that even when timber decomposes or is burnt, those emissions are then re-captured in the growing process, ultimately closing the loop. The timber lifecycle is also recognised for its relatively low carbon footprint and minimal amounts of waste. For example, at ASH, 100% of our timber is used, including our woodchips and sawdust which is used as green energy to power the site and animal bedding.

Overall, EPD’s are handy tools you can use to help minimise your environmental footprint during the design stages of your project. We hope this blog can help you make more informed decisions when choosing sustainable materials for your next project. To read the hardwood and glulam EPD’s, login to Wood Solutions here.

Read more about Timber's Circular Economy