New guidance on calculating embodied carbon of building services equipment

Clara Bagenal George
Clara Bagenal George

CIBSE has released guidance on the use of environmental product declarations (EPDs) for building services equipment. This guidance also provides a method for estimating the embodied carbon of building services equipment where EPDs are not yet available.

Reducing the impact of the built environment has become a priority in the face of a global climate crisis. To date, there has been a strong focus on operational carbon.  While embodied carbon is now starting to become a primary consideration the focus however, is often only structure and façades. Mechanical, electrical and plumbing (MEP) systems are often omitted or miscalculated. Yet initial studies show that MEP can account for nearly 80% of embodied carbon in retrofit schemes.

In addition to reducing operational carbon emissions, building services engineers must increase their awareness of embodied carbon emissions so that the whole life carbon impact of the systems they design and the products they specify is reduced.

Embodied carbon emissions are associated with the extraction and processing of materials, transport of products, replacement, disassembly and disposal.

MEP equipment often contains metals and plastics, which are associated with a high embodied carbon content and a complex supply chain, involving many manufacturing processes and long transport distances. Buildings often contain large quantities of MEP products which are also replaced regularly throughout a building’s life cycle.

How to reduce the embodied carbon of MEP products?

 Reducing the use and overall weight of MEP equipment is the most effective way to minimise its embodied carbon. The embodied carbon of MEP equipment can also be reduced by specifying equipment with low embodied carbon materials and through ensuring easy access for inspection, maintenance, and replacement to increase the lifetime of the product. Ensuring that products can be disassembled, and materials re-used and recycled is also important. For equipment with refrigerant, it is important to ensure low leakage rates and to specify that the refrigerant used must have a low GWP.

In order to understand the magnitude of the problem and the effect of embodied carbon reduction strategies it is necessary to quantify the embodied carbon of MEP products and systems.  

How to find out the embodied carbon of MEP products?

An environmental product declaration (EPD) is a standardised way of describing the environmental impacts, including the embodied carbon, of a product. Therefore, the starting point when trying to find information on a product’s embodied carbon is to ask the manufacturer if an EPD is available for the product.

However, it is not always that simple, as we know MEP products and their supply chains can be complex and the markets and regulators do not provide incentives for EPDs to be produced. As a result, very few manufacturers offer EPDs for their MEP equipment. With such limited access to this important information, the building services industry has had little access to vital data about how the embodied carbon of MEP products varies across different systems and products.

CIBSE TM65 embodied carbon in building services: a calculation methodology, looks to fill this gap. It provides:

  • Guidance on how to calculate the embodied carbon of MEP products when no EPDs are available - two methods are available depending on the information that can be accessed about a product.
  • A consistent approach for collecting the data required for the calculations.
  • A consistent approach to the way embodied carbon calculations for MEP products are undertaken and reported (at product level).

Details of the CIBSE TM65 methods

 When no EPD is available, information can be collected from the manufacturers of each product which is used to calculated the embodied carbon emissions for the MEP equipment.

Louise Hamlot
Louise Hamlot

What information is required

 TM65 offers 2 calculation methods. For the ‘basic’ calculation method, only information on material content and on refrigerants used, if relevant, is needed (section A of the ‘manufacturer’ form).

For the ‘mid-level’ calculation method, additional information such as energy used in manufacture and the location of the factory (sections A and B of the ‘manufacturer’ form) is needed.

Carrying out the calculations

 CIBSE TM65 provides a step-by-step guide for carrying out the calculations.

Reporting the results

 CIBSE would like to facilitate industry research on embodied carbon, and therefore encourages calculations to be shared by reporting results using a standard format (available from the CIBSE website). Any deviation from the CIBSE methods, either relating to methods or assumptions should be highlighted in the form.

Building services engineers can get involved in this research by:

 Requesting EPDs and sending manufacturers the ‘manufacturer’ form: Because there is currently little transparency surrounding the materials used in MEP products, gaining access to this data may be challenging. The first step is asking for an EPD. If the manufacturer does not have an EPD for the product in question, the ‘manufacturer’ form should be sent. The more requests for this type of data that manufacturers receive, the more likely it is that they will put additional resource into collating this information.

Helping CIBSE build a product database: Currently there is not much information on the material composition breakdown of MEP products. Any completed ‘manufacturer’ form should be sent to CIBSE.

Sharing research: If you as a consultant or engineer for products or systems calculate embodied carbon, please share the results with CIBSE, in order to form a knowledge base. As a result, research studies can be compared to find trends and to establish ‘rules of thumb’ guidance. Please also share assumptions and results in a standard format.

Louise Hamot and Clara Bagenal George from Elementa Consulting are the authors of the CIBSE TM65 Guidance.

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