Standard Documents

For Standard Requirements documents, please see below.
General Rules
Puro General Rules3.1June 2023
  • Removed Chapter 3.4 Certificate Expiry as per resolution in Advisory Board on 31 May, 2023. CORCs no longer expire automatically after 5 years.
  • Chapter numbering from Ch 3.5 unchanged for reference.
Puro General Rules3.0Dec. 2022
  • CORC minimum durability set to 100 years
  • Annex C discontinued: CORC issuance on Bio-based Building
  • Materials methodology (storage durability of 50 years) ceased from January 2023.
  • Chapter 1.2.3 added: reference to normative documents
  • Chapter 2.1.4 added: reference to leakage
  • Chapter 4 revised: description of “transfer of ownership” of a CORC instructed with a trade report
  • Chapter 5 revised to allow publishing of Audit Reports and project description
  • Enhanced Rock Weathering added as a valid Methodology.
  • All Methodologies and templates published as separate documents in website. Annex A-H removed from this document
Puro General Rules2.7October 2022
  • Annex B: Carbonated Building Material update from 2019 to 2022 to reflect the latest science
  • Chapter 1.3: Governance rules updated
Puro General Rules2.6.1May 2022
  • Page numbers corrected in Table of Contents
Puro General Rules2.6May 2022
  • Annex H: Woody Biomass Burial
Puro General Rules2.5.1May 2022
  • Minor spelling mistakes corrected
Puro General Rules2.5March 2022
  • Renaming of “Direct Purchase” to “Service Provider Trade” to align to Appendix 1 Terms and Conditions.
  • 4.2 Clarification of conditions related to Service Provider Trade.
Puro General Rules2.4.1Feb. 2022
  • Annex A: Biochar chapter 4.2 - Spelling correction of πΆπ‘œπ‘Ÿπ‘”  
Puro General Rules2.4Feb. 2022
  • Terminology change: replace "cancel/retirement" with "retire/retirement"
  • 5.1 Reporting: Added possibility for beneficiary to delay (embargo) the publishing of the retirement for maximum 12 months
Puro General Rules2.3Jan. 2022
  • 2.1.2 Environmental and social safeguards
  • 2.1.3 Additionality and Baseline
  • Annex A: Biochar methodology update from 2019 to 2022 to reflect the latest science
Puro General Rules2.2Dec. 2021
  • Chapter 1.3: Governance by Advisory Board
  • Chapter 3.8: Expiry extended
  • Chapter 5: Issuance and cancellation reports from the Registry 
Puro General Rules2.1Jun. 2021
  • Re-structuring: Separate chapters to describe rules for trading (Marketplace) and carbon removal crediting (Registry and Standard)
  • Annex G: Geologically stored Carbon methodology 
Puro General Rules2.0Jun. 2021
  • Chapter 3.1: Settlement is no longer tied to auctions
  • Chapter 3.4: Purchase through Certificate Listing Service enabled
  • Chapter 3.4: Pre-Purchase transactions enabled outside auctions
  • Chapter 3.4.3: Transfer Request added to Pre-purchase agreement process 
  • Chapter 4.3: Sale of CORCs enabled in external marketplaces
  • Annex A, 1.1.12: requirements for safe handling of biochar
Puro General Rules1.4Apr. 2020


  • Chapter 3.7 and 6.2: Extension of the expiry date by 6 months 
  • Chapter 3.5.6: Online shop closed for 3 hours before and after the auction 
  • Chapter 3.5: Possibility to select removal method in online shop 
  • Numbering of subparagraphs in Chapter 1.5. and Annex A,B,C 
Puro General Rules1.3Dec. 2019


  • Chapter 3.3: Certificate auctioning (changes from 48h blind to 96h half-blind)
  • Chapter 3.4: Pre-purchase of Certificates (changes due to action mechanism update)
  • Chapter 3.5 Certificate online purchase (added)
  • Chapter 6.2: CORCs issued in Experiment phase will expire normally 12 months after Issuance date. 
Puro General Rules1.2Oct. 2019


  • Chapter 3.2.4: CORCs may be issued for 18 months old production (previously 12 months)
  • Chapter 3.3: editorial changes 
  • Chapter 3.4: Pre-purchase of Certificates (CORCs)
  • Chapter 6.4: Aim to use CORC income for growth
Puro General Rules1.1Jun. 2019

Update to annex C and F

  • Annex C. Wooden Building element methodology modified to incorporate also biomass-based insulation materials. 
  • Annex F. List of signatories included confidentially (not changed)
Puro General Rules1.0Apr. 2019
Initial version elaborated with List of Signatories and published on website on the launch date of Puro CO2 removal marketplace.
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