What are EPD?
Environmental Product Declarations (EPD) are a standardised way of providing data about the environmental impacts of a product through the product life cycle. In Europe, they must conform to the European Standard, EN 15804, which ensures that EPD for construction products use a common methodology, report a common set of environmental indicators and have a common reporting format. This means that EPD can be integrated into building level assessment, and used to compare construction products in a building context. In EN 15804, the impacts of construction products are modelled over four life cycle stages – see figure below:
- The product stage (A1-A3) showing the impacts of manufacture and the supply chain from the “cradle to gate”;
- The construction stage (A4-A5) showing the impacts of transport and construction on site;
- The use stage (B1-B7) showing the impacts of any emissions in use, maintenance, expected repair or replacement and any energy or water consumed in use;
- The end of life stage (C1-C4) showing the impacts of demolition or deconstruction, transport to waste processing and any recovery or disposal processes.
EPD including all life cycle stages are known as “cradle to grave” EPD. EPD can also show the potential benefits of any reuse, recovery or recycling after end of life in Module D. These modules and stages are standardised across products and building level environmental assessment (using EN 15978, another of the CEN/TC 350 suite of standards for sustainable construction), so that EPD data can be easily used at building level to assess the life cycle impacts.
EN 15804 EPD are all independently verified (normally by a third party) and registered and published within EPD programmes which need to meet the requirements of International Standard ISO 14025. There are EPD programmes using EN 15804 across Europe, America and Australasia and in January 2018 there were over 5,400 registered construction product EPD verified to EN 15804.
A product with an EPD is not automatically a product with low environmental impact – the EPD only provides the environmental information about the product which allows you to discover this by comparing to other products at the building level. However, in obtaining an EPD, the manufacturer will receive an EPD Project Report which explains the sources of impacts through the life cycle, which will allow them to consider how they might best reduce them.
Because EPD to EN 15804 have a common methodology, EPD from different programmes can be used outside their country of origin, although often the data from “gate to grave” may not be representative as typical transport distances or end of life routes may be different in different countries.
What do EPD Measure?
All EN 15804 EPD report the same environmental impact indicators. These are:
Global Warming Potential (GWP)
GWP measures the Carbon Dioxide (CO2) and greenhouse gas (GHG) emissions associated with the manufacture and use of a product or service, sometimes known as “embodied carbon” or the “carbon footprint”.
Acidic gases such as sulphur dioxide (SO2) react with water in the atmosphere to form “acid rain”. When this rain falls, often a considerable distance from the original emission, it causes ecosystem damage.
Nitrates and phosphates are essential for life, but increased concentrations in water can encourage excessive growth of algae and reduce the oxygen within the water, which can lead to damage of ecosystems, increasing mortality of aquatic fauna and flora. Eutrophication can therefore be classified as the over-enrichment of water courses.
Stratospheric Ozone Depletion Potential (ODP):
Ozone-depleting gases (e.g. CFCs, HCFCs and halons) cause damage to stratospheric ozone or the “ozone layer”, reducing its ability to stop ultraviolet (UV) light entering the earth’s atmosphere. Growing concern in the 1980s led to world-wide efforts to curb the destruction of the ozone layer, culminating in the Montreal Protocol which banned many of the most potent ozone depleting gases.
Photochemical Ozone Creation Potential (POCP):
In atmospheres containing nitrogen oxides (NOx), a common pollutant, and volatile organic compounds (VOCs), ozone and other air pollutants can be created in the presence of sunlight. Although ozone is vital at high levels of the atmosphere (see ODP), low level ozone is implicated in impacts such as increased incidence of asthma. The most common manifestation of the effects of high levels of POCP-contributing gases is in the smog seen over large cities such as Los Angeles or Beijing.
Abiotic depletion indicators aim to capture the decreasing availability of non-renewable resources as a result of their extraction and underlying scarcity. There are two different indicators of abiotic depletion covering firstly scarce chemical elements, and secondly fossil fuels.
Abiotic Depletion (Elements) (ADPE):
This impact category indicator is related to extraction of scarce elements (and their ores) and is measured using the Production/(Ultimate Reserve)2which is compared to the reference case, Antimony (Sb).
Abiotic Depletion (Fossil Fuels) (ADPF):
This impact category indicator is related to the use of fossil fuels as fuel or feedstock and is measured using the primary energy of the extracted fuel.
In addition, EN 15804 EPD report the amount of primary energy used within the product (as feedstock, for example for plastics and wood) and to manufacture the product (as energy). Primary Energy is also broken down into energy from renewable sources, such as hydro-electricity and biomass, and from non-renewable sources – fossil fuels and nuclear energy. They also provide information on the amount of secondary (recycled) material used and the amount of recovered material, fuel or energy produced at end of life.
To find out more about EPD and how they can be used by construction professionals see our report.