Environmental product declarations for concrete

As the MPA releases a new suite of sector EPDs for ready-mixed concrete, Rachel Capon explains why these documents are becoming increasingly important and how designers can best use them to inform early-stage decisions

Environmental product declarations, or EPDs, provide transparent data on construction products to help designers choose building materials with lower environmental impacts. To ensure comparability across different products, the methodology to be used is set out by international standards such as the European standard for EPDs, EN 15804, and the complementary product category rules for concrete, EN 16757.

An EPD is based on a life cycle assessment (LCA) over the full product value chain using indicators for climate change and other environmental impacts, as well as resource use. For each indicator, the construction product life cycle is broken down into stages and sub-stages: material extraction, manufacturing and construction (modules A1-5); use (B1-7); end of life of the building (C1-4); and finally, recovery and reuse (D). The assessment and resulting EPD data must be independently verified by an accredited third-party.

EPDs are referenced in project-level carbon tools and assessments, such as the RICS Whole life carbon assessment (WLCA) standard, and the Future Homes Hub’s Whole Life Carbon Conventions. They are increasingly required to achieve green building certifications, and to drive lower-carbon
public procurement.

Different kinds of EPD

The most accurate measure of as-built environmental impact is given by a manufacturer-specific EPD for production of a specific product or material at the plant from which it is supplied. However, this level of detail is not always available. As an alternative, manufacturers may average data for a specific product over a number of their plants. They can also average data for different products produced at one or more plants to create an “average EPD”.

Multiple manufacturers can pool their data to create a “collective EPD”. Where a sector association, such as the Mineral Products Association (MPA), aggregates data from its members to create a collective EPD, this is known as a “sector EPD”.

Sector EPDs have multiple benefits and uses. They set an industry baseline that is independently verified. They can be used by designers to inform early-stage design choices, before a specific product or manufacturer has been selected. They enable manufacturers to benchmark the environmental performance of their own products. And concrete manufacturers without their own EPDs, who have provided MPA with appropriate manufacturing data, can reference them for procurement purposes.

Previously, sector association EPDs were often called “generic EPDs”, but the guidance and terminology for different EPD and data types used in environmental assessment has recently been updated. The new European data quality standard, EN 15941, says that this label should no longer be used.

Validity of EPDs and standards evolution

All EPDs expire after five years. The underlying methodologies also undergo periodic review. Notably, the European standard for EPDs, EN 15804, was amended in 2019, introducing additional requirements and indicators.

One of the key changes in the new standard is that the global warming potential (GWP) indicator – which measures the climate change impact from greenhouse gas emissions and removals – is broken down into three sub- categories: fossil, biogenic, and land use and land-use change. Another change is that all EPDs – with very limited exceptions – must now cover the whole life cycle of a construction product.

Specifically, for construction products containing biomass, this takes account of the CO2 sequestered during the plant or tree growth and its re-emission to the atmosphere at the end of life. For cement and concrete products, this also factors in CO2 removals due to the carbonation of concrete which takes place at end of life, but also during use and, in some cases, even earlier.

MPA sector EPDs for cement

Cement is the essential ingredient in concrete and the main contributor to its GWP. In 2022, MPA published two new sector EPDs for UK manufactured cement: UK average CEM I sector EPD and UK average Portland cement sector EPD, which align with the amended EN 15804 standard. The EPDs are modelled using aggregated data from all MPA member cement production sites and cover 100% of cement produced in the UK. The UK average CEM I sector EPD is a representative CEM I cement delivered in bulk. The gross GWP, based on 2020 manufacturing data, is 839.8kgCO2e per tonne. This can be used as an input in the calculation of EPDs for concrete mixes.

The representative UK average Portland cement sector EPD includes all UK-produced cement: CEM I and other cements sold in bulk, and bagged cements sold via builders’ merchants. It has a gross GWP of 812.3kgCO2e per tonne, again based on 2020 manufacturing data.

The “gross” value indicates that emissions from combustion of all fossil-based fuels used in the cement kiln – both virgin fuels and waste-derived fuels – have been included. When comparing EPDs, it is important to note that “net” GWP values (that is, excluding CO2 emissions from the combustion of waste-derived fuels) will be lower than gross GWP values.

As cement is chemically bound into concrete, and cannot be physically separated, it is one of the few exceptions to the new EN 15804 requirement to assess product impacts over the whole life cycle. Instead, the EPDs only measure the impacts for the manufacturing stage up to when the cement leaves the factory (modules A1-A3).

When comparing them with cement EPDs from other countries, it is important to note that in the UK supplementary cementitious materials (SCMs) such as fly ash or GGBS are typically added after the cement has left the factory, at the concrete mixing plant. In mainland Europe, SCMs are often added at the cement plant, so the GWP at the cement factory gate is lower.

MPA sector EPDs for ready-mixed concrete

In 2018, the British Ready-Mixed Concrete Association (BRMCA) published its first EPD for UK manufactured ready-mixed concrete based on the average of all concrete mixes produced by MPA members. In 2024, MPA published five new sector EPDs for ready-mixed concrete, which update the benchmark, but also help designers understand and quantify the impacts of their mix design choices. They represent frequently specified mixes at strength class C28/35, based on representative mix designs for CEM I, CIIB-V+SR, CIIC-SL+SR, CIIIA+SR and CIIIB+SR.

The EPDs cover the whole concrete life cycle: product manufacturing, construction, use, end of life, and recovery and reuse. Technically, this is described as cradle-to-gate, with additional modules A4- A5, B1, C1–C4, and D

Each EPD uses the MPA UK average

CEM I sector EPD for the CEM I component. Data for other raw materials (module A1) comes from the widely used Ecoinvent LCA database and verified EPDs. The transport of raw materials (A2), manufacturing of ready-mixed concrete (A3) and its transport to the construction site (A4) are based on data supplied by MPA members, averaged over their production sites.

The later life cycle stages assume typical scenarios based on current practice. The construction (A5) and use (B1) stages are based on use of ready- mix concrete in the superstructure of a six-storey concrete frame building. The end-of-life (C) and recovery and reuse (D) stages are based on typical UK practice for demolition, recovery and reuse, as described by the National Federation of Demolition Contractors. This states that all superstructure concrete is recycled at end of life, with 95% being crushed and reused in groundworks on or off-site. Recarbonation of concrete is included in modules B1, C1, C3 and D.

This collection of five EPDs highlights the range of options available to designers to specify lower- carbon concretes, such as the new multi-component cements in BS 8500:2023. The EPDs are published by EPD International. Machine- readable versions of these and the cement EPDs are available on Eco Platform by searching for “Mineral Products Association” as the EPD owner.

MPA sector EPDs for precast concrete

MPA Precast and MPA Masonry were early adopters of EPDs and published seven, covering a wide range of precast products. These are now being updated. MPA sector EPDs for three different densities of aggregate blocks and for aerated blocks are to be published later this year, followed by EPDs for architectural and structural precast concrete elements and precast flooring.

Rachel Capon is UK Concrete Sustainability Programme Coordinator at the Mineral Products Association