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TM65 Embodied carbon in building services: A calculation methodology (2021)
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TM65 Embodied carbon in building services: A calculation methodology (2021)

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Embodied carbon in building services: A calculation methodology outlines the need for assessments of embodied carbon of products linked to mechanical, electrical and public health (MEP) systems, to increase knowledge and facilitate research in whole life carbon in MEP systems. In this document, embodied carbon is understood as the greenhouse gas emissions (GHG) associated with the making of a product, its installation, its maintenance, repair, replacement, and then its end of life. It covers the whole life cycle, excluding operational aspects and the potential recovery, reuse or recycling of materials. The embodied carbon associated with MEP design can be significant in a building lifetime due to the materials that MEP equipment are made of and high replacement rates.

This document provides guidance on how to use environmental product declarations (EPDs) for MEP products. Where EPDs are not available, this document provides guidance on how to estimate the embodied carbon of MEP products.

This guidance provides a consistent approach for:

  • the data required from manufacturers
  • an embodied carbon calculation methodology for MEP products, depending on how much information from manufacturers is available
  • the way in which embodied carbon assessments are reported.

The purpose of this guide is to help the industry take a first step together to evaluate embodied carbon emissions in MEP design, alongside operational carbon emissions. The intention is that consultants and engineers that use this guidance will feedback their findings to CIBSE on the embodied carbon of MEP products. This will help to inform further iterations of this guide, as well as establishing guidance on actions that reduce the embodied carbon associated with MEP systems.

Click here to access the Embodied Carbon Calculator (the CIBSE TM65 Digital Tool)

For a demonstration of the Calculator, see the launch webinar here:

#GrowYourKnowledge - CIBSE TM65 Methodology

The forms associated with the Embodied Carbon Calculator can be accessed here: 

Embodied Carbon Calculator Input Form

Embodied Carbon Calculator Basic Report Form

Embodied Carbon Calculator Mid-level Report Form


1        Introduction    

          1.1       Context

          1.2       Aim of this document  

          1.3       Scope of this document

          1.4       How to use this document       

          1.5       Definitions       

1.5.1      Abbreviations       

1.5.2      General definitions              

1.5.3      Life cycle stage modules    

1.5.4      Carbon definitions                

          1.6       Embodied carbon impact in MEP design

2        MEP embodied carbon reductions      

          2.1       Embodied carbon reductions: basic actions       

          2.2       Circular economy principles     

          2.3       Low embodied carbon materials          

          2.4       Refrigerant leakage mitigation 

3        Environmental product declaration (EPD)      

          3.1       What is an EPD?           

          3.2       How to use an EPD?     

          3.3       Lack of EPDs for MEP products 

4        Embodied carbon calculation methods          

          4.1       Introduction    

4.1.1      Two calculation methods 

4.1.2      Calculation process workflow            

4.1.3     Relationship to RIBA Plan of Work stages      

          4.2       The ‘basic’ calculation method 

4.2.1      Manufacturer information

4.2.2      Method 

4.2.3      Product complexity              

4.2.4      Refrigerant emissions         

4.2.5      Reporting               

          4.3       The ‘mid-level’ calculation method       

4.3.1      Manufacturer information

4.3.2      Method 

4.3.3      Assumptions to be used in the ‘mid-level’ calculation method 

4.3.4      Reporting               

          4.4       Applicability of method and assumptions for projects outside of the UK and Europe      

4.4.1      Material carbon coefficient: A1       

4.4.2      Transport to site: A4            

4.4.3      Disposal: C2, C4   

5        Worked examples       

          5.1       ‘Basic’ calculation method        

5.1.1      Data requirements               

5.1.2      Example calculation             

          5.2       ‘Mid-level’ calculation method  

5.2.1      Data requirements               

5.2.2      Example calculation             

6        Extension of the method for advanced users 

          6.1       Creating generic data   

7        How to move forward

          7.1       How to move forward with whole life carbon in MEP design     

7.1.1      Next steps              

          7.2       Considerations beyond whole life carbon          

7.2.1      Next steps              

Appendix A: Further information on EPDs and other MEP embodied carbon data   

          A.1       Environmental product declarations (EPDs)       

A.1.1 Different types of EPDs            

A.1.2 Steps taken to create an EPD

A.1.3 Environmental impacts captured in an EPD        

A.1.4 EPD standards            

A.1.5 Requirement for EPD comparison        

A.1.6 Where to find EPDs for MEP products 

A.1.7 Example EPD               

          A.2       Other embodied carbon data for MEP products

Appendix B: Manufacturer data collection    

          B.1       Manufacturer data collection

B.1.1      Section A: Essential information     

B.1.2      Section B: Additional information required for ‘mid-level’ calculation   

B.1.3      Section C: Further information         

B.1.4      Section D: Information disclosure    

          B.2       ‘Manufacturer’ form    

Appendix C: Differences between an EPD and the CIBSE calculation methods         

          C.1       Summary table

          C.2       Relationship to RIBA Plan of Work stages          

          C.3       Further information on embodied carbon coefficients   

Appendix D: Evidence base    

          D.1       Why two calculation methods were developed  

          D.2       The use of EPDs within the development of the methods           

          D.3       The ‘basic’ calculation method 

D.3.1 Research showing that majority of embodied carbon is associated with stage A1 (material extraction)                

D.3.2 Factors that are used in the ‘basic’ calculation method  

D.3.3 Sense checking ‘basic’ calculation with EPDs      

          D.4       The ‘mid-level’ calculation method       

D.4.1 Life cycle stages         

D.4.2 Exclusions from the ‘mid-level’ calculation method          

          D.5       Refrigerant leakage assumptions in both methods        

Removable summary of ‘basic’ calculation method

Removable summary of ‘mid-level’ calculation method

Authors: Louise Hamot and Clara Bagenal George, Elementa Consulting Ltd.

Contributors: George Adams (SPIE), Jane Anderson (ConstructionLCA Ltd.), Tom Bunn (Arup), Duncan Cox (Thornton Tomasetti), Simon Ebbatson (Elementa Consulting Ltd.), Pat Hermon, Roger Hitchin, Helen Hough (Bryden Wood), Johanna Jarvinen (Bionova Ltd./One Click LCA), Anna Lasso (UL), Dr Qian Li (Cundall), Athina Papakosta (SCS Railways), Alex Pepper (Elementa Consulting Ltd.), Ina Peukes (Resource Efficient Built Environment Lab (REBEL), Edinburgh Napier University), Dr Barbara Rodriguez Droguett (Carbon Leadership Forum), Michelle Sanchez Brajkovic (PDP Architects), Dr Yair Schwartz (University College London (UCL)), Simon Sturgis (Targeting Zero), Sebastian Theien (TH K.ln — University of Applied Sciences, Institute of Building Services Engineering), Dr Joe Jack Williams (Feilden Clegg Bradley Studios).

Peer Reviewers: Dr Francesco Pomponi (Resource Efficient Built Environment Lab (REBEL), Edinburgh Napier University); Dr Julie Godefroy (Julie Godefroy Sustainability) and Simon Wyatt (Cundall).

To find out more about the TM65 authors, see our CIBSE Knowledge blog interview