Full-life Cradle-to-Grave calculation

Ben Adam Smith

Domestic heating is mostly using natural gas in this country, though that is changing, you may have heard that after 2025 gas boilers won’t be available.  The largest part of what remains after these head towards zero is the embodied CO2 of the construction.  Tim goes into more depth in a recent podcast (2020) podcast 283 with Ben Adam Smith of House Planning Help.

Input Data

  • built-in library of 200 material entries from EPDs and a further 100 from summaries of EPDs
  • data entry form, new easy-to-use form to enter your own data from additional EPDs
  • referencing, data is fully referenced with links to the EPD, source of the density and product life
  • density of product is in the database, a range can also be entered and for some products you can adjust the density
  • stored carbon for timber based products is included where it applies

Process and Usability

  • standard RICS methodology including 60 year nominal life
  • matches materials automatically,  you only need adjust the choice where necessary
  • remembers associations you make between phrases in the PHPP and materials
  • choose whether you want to see products manufactured within your country, a region e.g. Europe, or all the EPDs.

Outputs

  • fully transparent calculation
  • plenty of space provided for you to add comparison constructions
  • writes a “Scope Summary” form below the calculation for you to keep a record of exactly what is included
  • Operational CO2 also calculated and graphed with Embodied CO2 over 60 years (you can also graph for longer)
  • Printable AECB Assessment form
  • Coming Soon: Output in format suitable for RIBA awards applications

A recent project modelled with PHribbon embodied CO2 showing a comparison between the house as built and what it would have been using typical cavity wall of the same U-value.

The latest format now also shows what RIBA target it meets for domestic buildings (this is soon moving to a new summary tab) and a total CO2 graph which combines Operational and Embodied CO2 over the life of the building.

PHribbon calculates Embodied CO2 from Cradle to Grave, covering stages A-C (and D where information is available) and is suitable for initial estimates for the RIBA 2030 Challenge.  This therefore includes :
Stage A, A1-A3 Manufacture including A4 Transport to site and A5 Construction
Stage B, Use of the building including B4 Replacement
Stage C, Demolition and Disposal of the building
Stage D, Reuse, Recycling potential (outside the usual scope of the calculation)

You can buy the tool and do the calculation yourself, or Tim Martel also offers to do the calculation for you.
Technical details of the tool are available PHribbon -Tool Information Sheet.

Some of our recent calculations have been published in Passivhaus+ magazine (links are valid for subscribers and to others while Passivhaus+ is offering free access)

  • Steep Wedge House (new build) – issue 31 p49
  • PYC Offices (new build) – issue 32 p23
  • Greenheart Construction (new build) – issue 33 p29
  • Ruth Butler (new build) – issue 33 p38
  • and Passivhaus+ is keen to include these for regular feature of the projects they show issue 33 p18.

Results from the tool matched (within the error margins) Mark Siddall‘s own 2-3 day calculation. The Embodied tool was in development when Mark did his calculation and he was interested in a to see what it would produce, before revealing his own results. When it gave the same answer in about half an hour he said “I’ll definitely be using it next time”.