Category: Newsletter

Comparing EPDs offered by different manufacturers

On its own, an EPD is not a statement of whether a product is ‘sustainable’ or not. It is a tool for reporting the environmental impact of that product over its life cycle. Only through comparing the EPDs of different materials and products can an assessment can be made as to whether one will help to meet a project’s sustainability goals better than another.

When different manufacturers make EPDs available for their products, it’s important to look for similarities and differences in the reporting so that an appropriate assessment can be made.

Generic EPDs and manufacturer-specific EPDs

A first step in understanding commonality between EPDs is having an awareness of whether a product is being represented by a generic EPD or a manufacturer-specific EPD.

Generic EPDs use average data for similar products produced by a range of manufacturers, and report environmental impact accordingly. They might be offered by a trade association who has gathered data from its member companies, for example.

You could, therefore, find yourself requesting an EPD from two different manufacturers, and being provided with identical documents.

A generic EPD could be broadly representative of the environmental impact your product specification will have. However, there will always be a question as to how accurate it is, especially if a project is unique in a way that is unlikely to have been captured by ‘average’ data. More preferable is to obtain a manufacturer-specific EPD or, even better, a product-specific EPD.

A manufacturer-specific EPD can apply to more than one product (within a specific category of products) produced by a single manufacturer. A product-specific EPD applies to a single product from a single manufacturer.

In seeking to be transparent about the environmental impact of construction projects, the more specific the data the better.

What is functional equivalence in an EPD?

The environmental impact of a construction product is reported for a ‘unit size’ of that product. The EPDs that Polyfoam XPS makes available, for example, are based on one cubic metre of our extruded polystyrene. In the EPD document, this unit size is called the ‘functional equivalence’.

When comparing two EPDs from different sources, it’s important to check whether the functional equivalence is the same or different. For example, while our EPD uses one cubic metre as the basis for its reporting, there are EPDs for other types of lightweight rigid foam insulation that use one square metre of a specific product thickness.

One square metre of a 100mm thick insulation board has one-tenth the volume of one cubic metre of another insulation type. Even if the two insulation products had a broadly similar environmental impact, there would be a substantial difference in the figures reported by the EPD.

Manufacturers select the unit based on their production processes, so none of this is to say that one way is correct and another is wrong. It is simply something that specifiers have to check for when taking the EPD reporting at face value.

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A life cycle assessment, or LCA, analyses the environmental impact of a construction product across five stages: product, construction process, use, end of life, and the circular economy.

The results of the assessment are reported in a standardised document, an environmental product declaration (EPD), which can cover some or all of these stages. Currently, manufacturers can choose the scope of their reporting, but new rules are being introduced to make reporting across all stages and modules mandatory.

An environmental product declaration is an internationally recognised document that communicates environmental impact. They are produced in accordance with relevant standards and should be independently verified. EPDs can be created for products and services of all types, in all areas of life, but there are specific standards and rules covering the creation of EPDs for construction products.

To produce an EPD, life cycle analysis (LCA) is carried out for the product, with assumptions made about the environmental impact at different stages of that life cycle. The EPD document describes and reports that environmental impact, allowing designers, specifiers and other construction professionals to make informed decisions about product choices.

A big topic this year has been how manufacturers communicate about their construction products, and how information on performance and certification is presented. A few months ago we wrote a blog post on using manufacturers’ data to inform specification, and looked at a couple of different initiatives that will influence the way that manufacturers make data and information available to you as designers and specifiers.
 
One of those initiatives is the Code for Construction Product Information (CCPI). We first wrote about this back in May, and we’ve produced an update blog post to reflect on the subsequent publication of the Code and accompanying guidance.

Throughout 2021, we’ve used this newsletter to give you the essentials on various standards and guidance documents. We’ve tried to help you understand what’s important about them and what impact they have on your work.

This month we’re looking at the recently updated BS 5250, whose name has changed from Control of condensation in buildings to Management of moisture in buildings. On this occasion, it’s almost impossible for us to pick out the highlights and parts that are most relevant to your work. It’s all important!

Our new blog post about BS 5250:2021 therefore looks at what has changed and why you should seriously consider buying a copy. We always say that many standards are big documents with a price tag to match, but in the case of BS 5250:2021 the question you might have to ask is: can you afford not to have it?

As part of our ongoing series looking at “What do you need to know about…?”, this month we’re looking at some of the terminology and initiatives surrounding product data and product information.

Much of the current focus is on building safety, but specifiers increasingly require reliable and accurate information about environmental performance in order to make responsible decisions that can contribute to tackling the impacts of climate change.

Read our new blog post on construction product data to find out how better conversations between specifiers and manufacturers can help both parties to achieve better and more sustainable buildings.

We can probably name all the different performance requirements that a ground floor has to meet, but can we say that we always give them due consideration? Do we select the best type of ground floor insulation to suit the specific requirements of our project?

Thermal performance is usually the focus, with materials often chosen to meet a required U-value. But what loads will be imposed on the floor? What compressive strength does the insulation need to provide? And is the proposed specification ensuring that the floor meets the moisture protection requirements of the Building Regulations?

Follow the links above to read and share our ground floor blog posts, then email us, or reach us via the LinkedIn button at the bottom of the newsletter, if you have any comments or questions.

Last month we looked at the fundamentals of U-value calculations and what you needed to know about the combined method. This month, we’ve written about the specifics of ground floor U-values. Heat loss through a ground floor is different to any other construction element, and we look at the detail of what information helps us to provide you with the most accurate calculation.

Read our blog post to learn everything you need to know about BS EN ISO 13370

There are multiple facets to building performance, but the starting point for many is the U-values that different building elements have to achieve to keep thermal transmittance low. How are U-values calculated? Read our blog post to learn everything you need to know about the BS EN ISO 6946 standard.

For architects and specifiers looking to include an inverted flat roof as part of a construction project, ETAG 031 is a document that is very likely to be referenced in technical literature for inverted roof solutions. But what is ETAG 031, and how much do you need to know about it to help you successfully specify an inverted roof? Find out about ETAG 031 here.