Low Carbon Cement

This Protocol sets the specific requirements under which Environmental Attribute Certificates (EACs) are issued for low-carbon clinker, cement, and concrete.

Cement and concrete account for approximately 8 percent of global greenhouse gas (GHG) emissions, and many of the technologies needed to decarbonize the sector at scale, including carbon capture, utilization and storage (CCUS), novel binders, and kiln electrification, remain capital-intensive and early in deployment. Book and claim decouples environmental attributes from physical delivery, allowing demand to reach production sites regardless of geography and channeling investment into decarbonization at the point where emissions arise.

This Protocol is the clinker, cement and concrete-specific methodology layer of Isometric's EAC infrastructure. It operates under the Isometric Standard and refers to the Book and Claim Module, both of which set the cross-cutting requirements for EAC issuance, ownership, transfer, and lifecycle. This Protocol sets the requirements for eligibility, calculation methodology, integrity safeguards, and Certificate Attributes. Downstream claims made by Beneficiaries are governed by the relevant Buyer reporting frameworks.

Specific standards and Protocols which are utilized as the foundation of this Protocol and for which this Protocol is intended to be fully compliant with are as follows:

• Isometric Standard
• Isometric Book and Claim Module v1.0
• ISO 22095-3:2026. Chain of custody – Part 3: Requirements and guidelines for book and claim
• Corporate Net-Zero Standard Version 2.0

The Protocol also draws on the following Isometric Modules and Protocols, reference frameworks, and Buyer reporting standards:

• Isometric CO₂ Storage via Carbonation in the Built Environment Module

• Isometric Bio-CCS Protocol

• Isometric Biomass Feedstock Accounting Module

• Book and Claim for Cement and Concrete - Center for Green Market Activation and RMI

• Cement and Concrete Industry Chain of Custody Rulebook v1.0 - Global Cement and Concrete Association

• GCCA Low-Carbon Ratings - Global Cement and Concrete Association

• AIM Platform Standard V1.0 - AIM Platform

• Mitigation Action Accounting and Reporting Guidance V1.1 - Task Force for Corporate Action Transparency

• Accounting for Market Instruments - GHG Protocol (forthcoming, see Section 3)

• Product Category Rules for Construction Cements Part B v4.0, including the CCS add-on - Smart EPD

• Criteria for High-Quality Environmental Attribute Certificates in the Concrete and Steel Sectors - Microsoft and Carbon Direct

The Protocol also references the following secondary technical standards, product standards, and regulations:

• ISO 14025:2006 - Type III Environmental Product Declarations

• ISO 14044:2006 - Life cycle assessment requirements and guidelines

• ISO 21930:2017 - EPD core rules for construction products and services

• ISO/IEC 17029:2019 - Validation and Verification Body accreditation

• IWA 42:2022 - Net zero guidelines

• EN 15804+A2 - EPD core rules for construction works

• EN 16908 - Cement and building lime EPD product category rules

• EN 16757 - Concrete EPD product category rules

• EN 197-1, EN 197-5, EN 197-6 and EN 15743 - Cement composition, specification, and conformity criteria

• EN 206 - Concrete specification, performance, production, and conformity

• ASTM C150, C595, C1157 and ICC-ES AC529 - US cement product standards

• NSF International PCR 1112-19 - Product Category Rule for Concrete

• EU CCS Directive (Directive 2009/31/EC) - Geological storage of CO₂

This Protocol was developed based on the current state of cement decarbonization technology, the Buyer reporting frameworks and the reference frameworks published as of its release. Book and claim for cement and concrete is a developing market mechanism, and the frameworks this Protocol aligns with are themselves evolving. For example, the SBTi Corporate Net-Zero Standard V2 takes effect on February 1, 2027 and the GHG Protocol is developing a standard for Market Instruments.

The Protocol will be updated periodically in line with advancements in the available technology, the published frameworks, and market practice.

The Protocol recognizes three Functional Units: one metric tonne of clinker, one metric tonne of cement, or one cubic metre of concrete¹. EAC quantities issued, transferred, and retired on the Registry are recorded in these units. An EAC represents the carbon intensity of the product per Functional Unit. Certificate Attributes, including the Baseline value, Baseline type, and Emission Reduction Value, are carried alongside it, per Appendix D.

Clinker, cement, and concrete are distinct products, each with their own Baseline and its own emissions intensity threshold, and a separate EAC is issued against each Functional Unit. Product standards and Environmental Product Declaration (EPD) sourcing per Functional Unit are set in Section 7.1. No standalone clinker PCR exists, so a clinker EAC's EPD is prepared under the applicable cement PCR at a 100 percent clinker ratio. 

An EAC is issued against one Functional Unit and remains at that Functional Unit with no conversion route is available, per Section 11.2. Where the verified EPD reports Carbon Intensity in a different declared unit, the Project Proponent must convert the reported value to the applicable Functional Unit before issuance, and the conversion is confirmed by Isometric at Issuance Review..

Cement and concrete EACs are denominated in their own Functional Units, not in clinker-equivalent units. The conversion ratios between the three Functional Units vary widely, and that variation is itself driven by the decarbonization levers this Protocol certifies. Clinker-equivalent translation tables are provided separately, for buyer estimation only, per Appendix C.

A standalone Supplementary Cementitious Materials (SCMs) Functional Unit is not adopted in this version of the Protocol. An SCM may be certified at the cement or concrete Functional Unit, per Section 7.2.2, and an SCM producer may be the Project Proponent and hold the EAC for that unit, per Section 5.3. Certifying an SCM functional unit depends on methods that are still developing, in particular a consistent and assurable way to establish an SCM replacement rate, which no current standard yet provides². Isometric will review inclusion of SCMs as a Functional Unit in periodic updates to this Protocol per Section 3, once a recognized method for cement-unitized SCM replacement rates is published and in line with industry standards.

For each Project to be evaluated under this Protocol, the Project Proponent must document Project characteristics in a Project Design Document (PDD) as outlined in the Isometric Standard. The PDD will form the basis for Project Validation and evaluation in accordance with this Protocol, and must include consideration of items specific to cement and concrete EAC Projects:

• The Functional Unit against which EACs will be issued, and the production facility or facilities, per Section 4.

• The verified EPD and the applicable Product Category Rule (PCR) for the certified product, per Section 8.2.

• The decarbonization pathway and the selected Baseline type, per Section 7.2 and Section 8.4.1.

• The Financial Additionality declaration, the Regulatory Additionality category with the underlying regulatory disclosure per Section 5.4.4, and the Catalytic Impact narrative per Section 7.4.

• The environmental and social risk assessment and its associated mitigation and monitoring plans, per Section 6.

• For Projects relying on CCS, the storage site and operator, the storage permit and any applicable long-term stewardship regime, the MRV Protocol reference, and the Risk of Reversal assessment, per Section 9.

Projects must be Validated by a Validation and Verification Body (VVB) selected and engaged by Isometric and are subject to annual Surveillance Audits, consistent with Section 4 of the Isometric Standard and the Assurance requirements in Section 8 of the Book and Claim Module³. At each Surveillance Audit and at re-Validation, the VVB reviews a representative sample of the issuance requests made since the previous audit and confirms their conformity with the Validated scope of The Project and this Protocol. This section sets out the cement, concrete and clinker-specific requirements that apply in addition to that framework.

The VVB must maintain team expertise in the decarbonization pathway certified under this Protocol. The materiality threshold applied at Validation and each Surveillance Audit is that of the applicable PCR, per Section 8.2. Qualitative materiality issues, including control weaknesses, poorly managed documentation, and regulatory noncompliance indirectly related to greenhouse gas emissions, must additionally be identified and documented.

Each EAC issuance request is subject to an Issuance Review carried out by Isometric, per Section 4.2.3 of the Isometric Standard. An Issuance Review does not require a VVB.

The EPD that carries The Project's certified carbon intensity is separately verified under ISO/IEC 17029 for the applicable PCR. The VVB requirements for the EPD, including the additional accreditation required where the certified product relies on CCUS, are set Section 9.

The ownership requirements of Section 3.1 of the Isometric Standard apply to Projects certified under this Protocol. A single Project Proponent must be specified as the sole owner of the Environmental Attributes represented by each EAC issued under this Protocol. A party other than the Project Proponent is a Project participant where The Project depends on data or evidence from that party, or where that party could otherwise claim the emissions performance of the input it supplies. The Project Proponent must hold a contract with each Project participant meeting the requirements of Section 3.1 of the Isometric Standard, and must identify each Project participant and its role in the PDD. A party that supplies an input on arm's length terms is not a Project participant where it does not market that input on the basis of its emissions performance and the input's carbon intensity enters the verified EPD as a published or secondary dataset value.

For Projects certified under this Protocol, this test applies to the parties commonly involved in a cement value chain, for example:

• Storage site owners and operators are Project participants in every CCUS Project, because the Project Proponent relies on the operator for storage monitoring data and for the MRV Protocol output referenced in the verified EPD. Continuity across the Reporting Period is set in intervention is a CCUS pathway. Storage operator continuity across the Reporting Period is set in Section 9.7.
• External clinker producers are Project participants where the clinker's certified Carbon Intensity is the source of the Environmental Attribute represented by the cement EAC.
• External Supplementary Cementitious Material (SCM) producers are Project participants where the cement or concrete producer is the Project Proponent and the SCM producer could otherwise claim the emissions performance of the material it supplies. Where the SCM producer is instead the Project Proponent, the cement or concrete producer is the Project participant, and the contract requirements apply to it.
• Biomass feedstock suppliers are Project participants where the Project Proponent relies on the supplier for the sourcing evidence required under Section 6.1

Additionality asks whether a Project's decarbonization goes beyond what would have happened without EAC revenue. Buyer-side frameworks approach this differently.  Rather than fix a single Additionality bar, this Protocol reports Project-level information against each pillar so Buyers can apply whichever bar their own framework or claim requires. Catalytic Impact, being whether a Project meaningfully advances the sector's decarbonization frontier, is a separate concept and is addressed through the mandatory Catalytic Impact narrative in Section 7.4. The four pillars of Additionality are assessed as follows.

Environmental Additionality asks whether the certified reduction is real, measurable, and below a Baseline. Under this Protocol it is satisfied by the eligibility criteria and requires no separate test. A Project must carry a verified EPD (Section 7.1) and meet the emissions intensity threshold outlined in Section 7.3.

Common Practice Additionality asks whether the decarbonization activity is already widespread in the sector. The assessment is folded into the following two mechanisms:

• The emissions intensity threshold in Section 7.3 excludes production above the applicable GCCA Low-Carbon Ratings band, screening out business-as-usual output.
• The Catalytic Impact narrative in Section 7.4 requires the Project Proponent to disclose market-penetration and sector-adoption data.

Financial Additionality asks whether EAC revenue is necessary to enable the decarbonization decision. The counterfactual is a conventional facility, not the absence of a facility, so the question is whether EAC revenue closes the remaining viability gap for the decarbonization decision specifically.

Under this Protocol, Financial Additionality is not separately tested at issuance⁴. The following mechanisms together screen out Projects whose decarbonization would have occurred without EAC revenue: the emission intensity the emissions intensity threshold in Section 7.3, which excludes production above the applicable GCCA Low-Carbon Ratings band and so screens out business-as-usual output; the exclusion of traditional Supplementary Cementitious Materials in Section 7.2.2; and the Regulatory Surplus criterion in Section 5.4.4.

A Project Proponent may optionally select an enhanced pathway, in which Financial Additionality is demonstrated through the full Project financials and Internal Rate of Return analysis set out in the Financial Additionality section of the Isometric Standard. The IRR analysis must reflect all cement-specific components of The Project's economics, including:

• the decarbonization capital expenditure
• the operating cost differential relative to the conventional counterfactual,
• all revenue streams received for the certified activity, including government subsidies, tax credits, freed emissions trading system allowances, and expected EAC revenue.

Sensitivity analysis must vary energy prices, feedstock and reagent prices, emissions trading system allowance prices where applicable, and the expected EAC price, in accordance with the ±20 percent floor in the Isometric Standard.

An EAC issued under this pathway carries the Enhanced Financial Additionality Declaration label on the Registry. The VVB confirms the IRR analysis at Validation and reassesses at each Surveillance Audit, and in particular where the Project Proponent's position on any of the government subsidies, tax credits, emissions trading system allowances, or primary decarbonization input costs changes materially over the Crediting Period.

Regulatory Additionality asks whether the certified reduction goes beyond what regulation already requires, and whether the same reduction has been used to meet a compliance obligation. The activity may be legally required regardless of EAC revenue, in which case the reduction would have happened anyway, or the reduction may have been surrendered against a compliance obligation, in which case counting it again would count it twice.

This Protocol addresses both through a single Regulatory Surplus test, applied to every EAC issued under this Protocol, using the definition and process set out in Appendix G of the AIM Platform Standard V1.0⁵. Regulatory Surplus is tested at the entity and immediate supply chain level. System-level allowance dynamics under cap-and-trade programs are not addressed. Where the AIM Platform Standard is updated, this Protocol is reviewed and, where required, updated at the next version release, per Section 3.

The Project Proponent must declare a Regulatory category from the four classes and provide the required Regulatory Surplus Evidence, as set out in Table 2.

Table 2. Regulatory categories and claim eligibility

The Regulatory category and the Regulatory Surplus Evidence are recorded on the EAC, publicly visible on the Registry, and confirmed by the VVB at Validation and at each Surveillance Audit.

Uncertainty in the carbon intensity carried on an EAC is inherited from the applicable PCR and the EPD prepared under it (Section 8). The PCR sets the data quality requirements, materiality threshold, and sensitivity analysis approach that govern the reported value.

This Protocol does not layer a separate quantitative uncertainty framework on top of the applicable PCR. Where this Protocol and its referenced PCRs are silent, the general uncertainty accounting principles in the Isometric Standard apply.

In accordance with Section 3.12 of the Isometric Standard, all evidence and data related to EAC issuance under this Protocol will be publicly available through the Isometric Registry. This includes the following: 

• Project Design Document

• Verified EPD and the applicable PCR

• Baseline value, type, source, and vintage

• MRV Protocol reference and its outputs, for CCS projects

• VVB statements

• Full Certificate Attribute set at issuance

The Project Proponent may request certain information to be restricted, available only to authorized buyers, the Registry, and the VVB, where the information is subject to confidentiality. That restriction does not apply to any numerical data used to quantify the carbon intensity, the Emission Reduction, or the stored CO₂ credited within a CCS-backed EAC.

A clinker, cement, or concrete EAC Project must consider the material environmental and social impacts that could arise from its activities, both within and beyond its Project boundary, and must demonstrate no net environmental or social harm. The overarching requirements are set out in the Environmental and Social Impacts section of the Isometric Standard. This section states the specific requirements that apply above those baseline obligations. Compliance with this section will be assessed by the VVB at initial Validation and at each annual Surveillance Audit.

The following requirements apply and must be addressed explicitly in the PDD, in addition to the general risk identification required in the Isometric Standard.

• Particulate emissions and dust: Cement manufacturing generates particulate matter from kiln exhaust, clinker cooling, and raw material handling. The Project Proponent must document emissions controls for particulate matter and must confirm that operational emission levels comply with local air quality regulations. Where local regulations do not exist, the Project Proponent must apply the most stringent standard of the European Union or the United States Environmental Protection Agency.
• Water use: Wet process kilns, slurry handling, and CCS cooling systems can place material demands on local water resources. The Project Proponent must provide qualitative water efficiency and stewardship assessment, with particular reference to water availability in the project area and any competing industrial or agricultural demand.
• Carbon capture: Projects using carbon capture for CCU or CCS must consider the risk of solvent and sorbent emissions to air from capture systems, including amine volatilization, nitrosamines, and nitramines. Emission levels must be documented and must comply with applicable regulatory limits.
• CO₂ storage site safeguards: Projects relying on CCS must address the following risks:
  • Geological storage integrity: the Project Proponent must describe the monitoring program, associated permit for CO₂ storage containment and must reference the storage verification plan required by Section 9.1 of this Protocol.
  • Surface and groundwater quality in the vicinity of the injection or storage site.
• Biomass feedstock sustainability and prohibited feedstocks: Where the intervention uses biomass feedstock, the Project Proponent must apply the following sections of the Biomass Feedstock Accounting Module v1.3:
  • Section 2.1 Sustainability Criteria. The Project Proponent must satisfy all criteria in the sustainability table matching the feedstock type (SC1 forestry residues, SC2 retrofits using forestry residues, SC3 crop residues, SC4 animal agriculture residues, SC5 food processing, landscaping or other industry residues, SC6 municipal waste, or SC7 invasive species).
  • Section 4.1 Prohibited Feedstocks. The Project Proponent must satisfy PF1 for non-woody feedstocks and PF2 for woody feedstocks.

The storage operator is typically a separate legal entity from the cement producer. The PDD must identify which party is responsible for each CCS-related safeguarding obligation and must demonstrate that responsibilities are contractually allocated for the full duration of storage monitoring, including post-handover obligations per Section 9.7 of this Protocol.

Environmental and social safeguarding data generated under this section must be made publicly available through the Isometric Registry. The Project Proponent may request that specific data be restricted where confidentiality concerns apply, subject to the data restriction rules in the Isometric Standard.

This section sets out the eligibility requirements for EAC issuance under this Protocol. A Project must meet the following requirements: the EPD and PCR requirements in Section 7.1, the pathway and exclusion rules in Section 7.2, and the emissions intensity threshold in Section 7.3. In addition, the Project Proponent must submit a Catalytic Impact narrative under Section 7.4, which is a mandatory disclosure for Buyers to assess against their own framework requirements at retirement. 

The VVB confirms compliance across all four at Validation. Ongoing compliance is confirmed at each Surveillance Audit.

The certified product must be certified to a recognized cement, clinker, or concrete product standard, and must be covered by a verified EPD meeting the requirements of Section 8.2.

Recognized product standards, by Functional Unit:

• Cement: EN 197-1, EN 197-5, EN 197-6 or EN 15743, or ASTM C150, C595, C1157, or AC529, or an equivalent national or regional cement product standard.
• Clinker: No standalone clinker PCR exists, so the EPD for a clinker EAC must be prepared under the applicable cement PCR per Section 8.2, with a 100 percent clinker ratio, and must identify the declared product as clinker⁶.
• Concrete: EN 206, ASTM C94, or ASTM C685, or an equivalent national or regional concrete product standard.

A novel binder that does not conform to any recognized cement product standard is eligible only through the novel-binder pathway in Section 7.2.2, which sets the technical dossier requirements in lieu of standard conformity.

This Protocol is technology-agnostic. Any decarbonization pathway that meets the eligibility criteria in this section and the emissions intensity threshold in Section 7.3 may issue EACs. There is a published exclusion list to prevent low-integrity pathways from qualifying by default.

Eligible pathways include, but not limited to:

• Carbon Capture and Storage (CCS) or Carbon Capture and Utilization (CCU) applied to any CO₂ stream arising from the certified production process, however generated, subject to the additional requirements in Section 9.

• SCMs, subject to Section 7.2.2.

• Novel binders, including geopolymers, alkali-activated binders, and electrochemically produced binders, subject to the novel-binder pathway in Section 7.2.2.

• Kiln electrification.

• Biomass fuel switching, subject to the biomass sourcing requirements in Section 6.1 and Section 7.5.

The following are excluded:

• Enhanced Hydrocarbon Recovery as a storage or utilization destination for captured CO₂⁷.
• Renewable electricity procurement as the sole decarbonization lever. Renewable electricity may contribute to a Project's carbon intensity reduction, but must not be the primary lever.
• Carbon utilization pathways without durable storage, as further specified in Section 9.2.
• Traditional SCMs when used as a primary driver for decarbonisation, as specified in Section 7.2.2.

The exclusion list is not exhaustive. A pathway not named in either list is evaluated on the basis of the eligibility criteria in this section, and the emissions intensity threshold in Section 7.3.

A Supplementary Cementitious Material (SCM) partially substitutes Portland clinker in a blended cement or concrete, reacting within a clinker-based system rather than serving as a stand-alone binder. This includes traditional SCMs, being fly ash and ground granulated blast-furnace slag, and Novel SCMs, being SCMs other than fly ash and ground granulated blast-furnace slag, for example calcined clay, ground glass pozzolan, and natural pozzolans. Whether a material is an SCM or a Novel Binder is determined by its role in the certified product. A material that substitutes a share of clinker within a clinker-based system is an SCM. Where the same material replaces clinker as the primary binder, it is a Novel Binder and is treated under Section 7.2.3. The same material may be an SCM in one certified product and a Novel Binder in another.

EACs must not be issued for any cement or concrete where a traditional SCM, being fly ash from coal-fired power plants or ground granulated blast-furnace slag, is the primary driver of the emissions reduction relative to the Baseline⁸. This exclusion applies regardless of the product standard under which the product is certified and the route by which it enters this Protocol. A slag-dominant or fly-ash-dominant cement certified under EN 197-5, EN 197-6, or EN 15743 is treated the same as an equivalent cement certified under EN 197-1. The exclusion does not apply where the traditional SCM has been Beneficiated. It is not lifted by activation, or by any processing that is ordinarily part of bringing the SCM to market. Novel SCMs, and mixed-lever blends in which a traditional SCM is not the primary driver, remain eligible. The following definitions apply:

• A Beneficiated SCM is defined as a traditional SCM recovered or upgraded from a source that was not otherwise usable as an SCM, such that the intervention adds low-carbon supply rather than crediting routine use, for example harvesting and processing ponded or landfilled ash, or thermal treatment to remove residual carbon. Grinding or classification is Beneficiation only where the source material was not otherwise a marketable SCM.
• An Activated SCM is defined as a traditional SCM whose latent reactivity has been deliberately raised above its as-produced state by a treatment step beyond the processing ordinarily applied to bring that SCM to market. Grinding or classification that is part of the SCM's normal production, including the grinding of granulated blast-furnace slag, is not activation.

The VVB applies the primary-driver test at Validation, using a qualitative assessment of the largest single contributor to the difference between the Project and Baseline EPDs. Where the VVB cannot establish from existing data whether a traditional SCM is the primary driver, or whether it has been Beneficiated, it may require testing by an independent reviewer that is an accredited testing body. The independent reviewer is engaged directly by Isometric and must have no commercial or contractual relationship with the Project Proponent.

An SCM is certified at the cement or concrete Functional Unit, either through the cement or concrete it is blended into or, where the SCM producer is the Project Proponent, through a qualifying contract with the downstream producer, per Section 5.3. Replacement rates are delegated to the verified EPD under the relevant PCR. This Protocol sets no default replacement factors.

A Novel Binder replaces clinker as the primary binder rather than substituting a share of it within a Portland system, so it functions as a stand-alone binder, its primary reactive chemistry differing fundamentally from Portland clinker in that role. Examples include geopolymers, alkali-activated binders, and electrochemically produced binders. The distinction from a Novel SCM turns on this role, as set out in Section 7.2.2. Examples include geopolymers, alkali-activated binders, and electrochemically produced binders. A Novel Binder removes the need for clinker rather than substituting a share of it, which is what distinguishes it from a Novel SCM treated under Section 7.2.2.

A novel binder certified under ASTM C1157, EN 197-5, EN 197-6, EN 15743, or an equivalent national or regional cement product standard enters through the main issuance path under Section 7.1. A standard is equivalent for this purpose where it is issued by a recognized national or regional standards body and sets composition and performance requirements at least as stringent as the named EN or ASTM standards, which the VVB confirms at Validation. Where the certified product's composition permits a traditional fossil SCM to be the primary driver of the reduction, for example a slag-dominant cement under EN 15743 or EN 197-5, the VVB applies the primary-driver test in Section 7.2.2 before issuance, and the exclusion in Section 7.2.2 applies. A novel binder that fits no recognized cement product standard, or holds only a product-specific technical approval, routes through the novel-binder pathway, where any approval is submitted as supporting evidence rather than as a substitute for review. The Project Proponent must submit a technical dossier to Isometric covering:

• chemical composition;
• mechanical performance, including compressive strength curves, setting times, and workability;
• durability, including chloride resistance, sulphate resistance, alkali-silica reaction resistance, and carbonation depth; and
• a cradle-to-gate Life Cycle Assessment per ISO 14044, in lieu of a PCR-compliant EPD.

The VVB reviews the technical dossier at Validation. Where equivalence to the reference conventional cement type cannot be established from the dossier alone, for example, because the required mechanical performance or durability tests were not conducted to a recognized test standard, or because no standard exists for the property under review. Isometric will engage an independent reviewer with binder-chemistry, mechanical-performance, or durability expertise, as applicable, to confirm the equivalence-determining tests. The independent reviewer is engaged directly by Isometric and must have no commercial or contractual relationship with the Project Proponent.

Isometric defers to the clinker-equivalent translation table in Appendix C to identify the closest functionally equivalent conventional cement type and its mass-equivalence factor, typically 1 : 1⁹. The novel binder then enters the main issuance machinery via that reference equivalence, with Baseline and matching rules applied as for the reference cement type. Isometric maintains the equivalence table and re-evaluates each entry at intervals of no more than 12 months, and sooner where new data, an updated dossier, or a change in standard conformity materially affects the applicable reference cement type or mass-equivalence factor.

Replacement rates are delegated to the verified EPD under the relevant PCR. This Protocol sets no default replacement factors.

Each EAC must carry the SCM or novel binder type (non-beneficiated fly ash, beneficiated ponded ash, electric arc furnace slag, calcined clay, or novel binder) and its contribution percentage by mass, being the constituent's mass fraction of the certified product as reported on the verified EPD, as one of the Certificate Attributes in Appendix D.

The certified product must have a carbon intensity at or below the emissions intensity threshold applicable to its Functional Unit, production region, and production vintage. For output produced from 2025 to 2029, the threshold is Band C of the GCCA Low-Carbon Ratings for cement and concrete. For output produced from 2030 onwards, the threshold tightens to Band B¹⁰.

Bands are regionalized. Country-level Band C and Band B values for cement, as of January 2026, are set out in Appendix B. The Project Proponent must apply the country value published for the country in which the certified product is produced, per Appendix B. Where the country is not listed, the global values apply.

The corresponding threshold for a clinker EAC is the Band C or Band B value at a 1.0 clinker-to-cement ratio (100 percent clinker) for the applicable country. The corresponding threshold for a concrete EAC is derived from the applicable cement band using the cement-to-concrete ratio recorded on the verified EPD. 

The applicable band is set by production vintage. A quantity of certified output is assessed against the band in effect for the year of the Reporting Period in which it was produced. Once EACs have been issued against a production vintage, the band that applied at that vintage governs those EACs, and a subsequent tightening of the threshold does not retroactively disqualify them. On renewal of the Crediting Period, The Project is re-Validated against the band applicable to the new Crediting Period, per the re-Validation requirement of the Isometric Standard.

The threshold applies at Validation, at each subsequent Surveillance Audit and Issuance Review, and at re-Validation. A Project whose emissions intensity rises above the band applicable to a production vintage may not issue EACs for the Reporting Period of that vintage.

Catalytic impact asks whether a Project drives genuine market transformation of the cement sector, beyond producing a lower-carbon product. It is distinct from the Additionality assessment in Section 5.4: a Project may satisfy the Additionality pillars without meaningfully advancing the sector's decarbonization frontier.

Every Project Proponent must submit a Catalytic Impact narrative at Validation¹¹. The narrative is disclosed on the Registry, per Section 12 and Beneficiaries assess catalytic impact against their own framework requirements at retirement.

Buyer thresholds vary and illustrative benchmarks include: a credible path to at least 10,000 tonnes CO₂e per year of emissions reduction by 2030 and 100,000 tonnes per year by 2035 (Meta Sustainable Materials Program), at least 50 percent LCA abatement (AIM Platform Standard V1.0), and system-level impact demonstration for consequential claims (SBTi V2 C27.5).

The narrative must address the following five items:

1. Target deployment scale and timeline. State the deployment scale the technology is expected to reach, expressed in tonnes of low-carbon cement or clinker-equivalent per year, and the target year for reaching it.
2. Cost-down trajectory and cost drivers. State the primary cost drivers of the certified decarbonization activity and the expected direction of cost change over the Crediting Period, with the mechanisms expected to drive that change (for example economies of scale, learning-by-doing, or supply chain maturation). A quantitative cost trajectory is not required.
3. Dependencies. Identify the material dependencies that must be resolved for The Project to reach its target deployment scale over the Crediting Period. Dependencies must include, where applicable, storage permitting, feedstock or supply chain, regulatory or standards development, and grid or infrastructure readiness.
4. Common practice and market penetration. State the current sector adoption rate of the certified decarbonization activity in the relevant geography, including the percentage of comparable cement production using the same lever, whether the activity is widely available today, and whether the lever is expected to remain distinctive versus common practice over the Crediting Period. State whether the intervention is at commercial scale or at pre-commercial (pilot or demonstration) scale, and, where pre-commercial, the current stage of deployment. State the geographic scope of the common-practice assessment and justify why that scope is the appropriate market comparison for the certified decarbonization activity.
5. Credible scaling pathway. State a credible pathway to a defined absolute deployment scale, expressed in tonnes of CO₂e per year of emissions reductions, by a stated target year. Evidence must include capacity projections, offtake commitments or letters of intent, and any relevant capital allocation decisions. This Protocol sets no absolute threshold on the scaling pathway.

Where the intervention uses a biomass feedstock, the Project Proponent must apply Section 4.2 of the Biomass Feedstock Accounting Module v1.3 to screen out feedstocks whose diversion to the intervention would displace prior uses to a higher-emitting substitute or lead to indirect land use change. The Project is eligible for EAC issuance only if the Project Proponent satisfies one of the market displacement tests ML2, ML3, ML4, ML5, ML6, or ML7. The criterion is confirmed by the VVB at Validation and reconfirmed at each Surveillance Audit.

This section sets out the calculation methodology for all EACs issued under this Protocol: how the carbon intensity of a certified product is measured, how allocation is handled, EPD requirements and how Baselines and Emission Reduction Value are constructed.

The cross-cutting principles for the GHG accounting boundary, Uncertainty, default emission factors, and proxies are set in Section 2.5.2.2, Section 2.5.4, and Section 2.5.6 of the Isometric Standard, and the EAC-specific treatment of Carbon Intensity, Emission Reduction Value and Baselines is set in Section 5 (Calculation Methodology) of the Book and Claim Module. Neither is restated here.

The carbon intensity of a certified product is the value reported on the verified EPD prepared under the applicable PCR per Section 8.2, expressed in kg CO₂e per Functional Unit. That value is carried on the EAC as one of the Certificate Attributes under Appendix D.

A PCR sets the rules under which an EPD is calculated for a defined product group, including the GHG accounting boundary, allocation rules, data quality requirements, and reporting conventions. The PCR is what makes EPDs for the same product type comparable across producers, and what makes the reported carbon intensity a defensible basis for an EAC.

An EPD for the purpose of underlying product certification is acceptable under this Protocol where it meets all of the following:

• Prepared as a Type III EPD under ISO 14025.
• Prepared under a PCR that covers the certified product, or one of the specified fallbacks below.
• Product-specific and facility-specific. Industry-average and manufacturer-average EPDs are not acceptable.
• Verified by a VVB (the "EPD VVB") accredited under ISO 14065 and ISO/IEC 17029 for the applicable PCR, being accreditations recognized under Section 4.1 of the Isometric Standard, or holding an equivalent accreditation recognized by the EPD program operator for that PCR, per Section 3.13 of the Isometric Standard. Where the certified product relies on CCUS, the EPD VVB must additionally be accredited for the Smart EPD Part B v4 CCS add-on. Where a single body is not accredited for both, the Project Proponent may engage a second EPD VVB accredited for the add-on and cross-reference the two verification statements. The Project Proponent engages the EPD VVB and Isometric selects and engages the VVB that conducts Project Validation and Surveillance Audits, per Section 4.4 of the Isometric Standard. Where a single body holds both accreditations it may perform both functions, per Section 3.13 of the Isometric Standard, but each is engaged by a different party.
• Reports carbon intensity for life cycle stages A1 to A3 (cradle-to-gate) at minimum.

The Project Proponent must apply the PCR of the production jurisdiction where one covers the certified product. Where no PCR exists in the production jurisdiction, or where the jurisdiction's PCR does not cover the certified product, the Project Proponent must apply one of the following as fallback:

• For clinker and cement: EN 16908:2017+A1:2022 or Smart EPD Part B PCR for Cements for Construction Standard 1000-010 v4.0.
• For concrete: EN 16757:2022 or NSF International PCR 1112-19 v2.3 for Concrete.

Where the certified product relies on CCUS, the Smart EPD Part B v4 CCS add-on must additionally be applied for the CCS-specific components regardless of the production jurisdiction, per Section 9, because it is the only PCR with CCS provisions¹².

Where an accepted EPD is issued under the International EPD System as an EPD of a product recently on the market¹³, it must meet the requirements of Section A.9.5 of the International EPD System's General Programme Instructions (GPI 5.0.1)¹⁴ in full. This includes the required cover-page and product-information disclaimer; the condition that any LCI data drawn from a period shorter than one year of production be proven to be conservative relative to one-year data, accounting for seasonal variations and productivity effects (A.9.5); and the obligation to update and re-verify the EPD within six months of one year of production data becoming available, failing which the EPD shall be depublished. Equivalent provisions in other recognised EPD programmes apply on the same basis.

The following principles apply to any EPD used for EAC issuance under this Protocol:

• No adjustment for regulatory position: The reported carbon intensity is not adjusted to account for free allowances received under an emissions trading system, or for any other regulatory position of the Project Proponent¹⁵. Regulatory-instrument interactions are handled through the Regulatory Additionality category assignment in Section 5.4.4.
• Biogenic CO₂: Biogenic CO₂ is treated as climate-neutral and does not enter the carbon intensity reported on the EAC. Full treatment, including where biogenic CO₂ is permanently stored, is set in Section 9.4.
• Carbonation and calcination: Reporting of calcination emissions and carbonation uptake follows the applicable PCR. Under Smart EPD Part B v4, this is Section 7.2.8, referring to ISO 21930 Sections 7.2.8, 7.2.12, and 9.5.2. Regional PCRs apply their equivalent provisions.
• Co-product allocation: Follows the applicable PCR and ISO 14044, applying the ISO 14044 hierarchy of subdivision, physical or causal allocation, and economic allocation as a last resort.
• Measurement data hierarchy: Follows the applicable PCR, preferring facility-specific primary data over regional averages and regional averages over global generic data.
• Uncertainty: Inherited from the applicable PCR and EPD methodology. The framing that applies across the Protocol is set in Section 5.5.
• Age: An EPD must be no more than 12 months old at the time of EAC issuance. Where it is older, the Project Proponent must submit a sensitivity analysis, confirmed by Isometric at each Issuance Review, demonstrating that the reported Carbon Intensity does not materially understate the current Carbon Intensity of the product. The materiality threshold applied is that of the applicable PCR, referencing the underlying ISO 21930 or EN 15804 provisions where the PCR is silent. Where the analysis shows that the current carbon intensity is equal to or lower than the reported value, the EPD remains acceptable and the EAC continues to carry the reported value. A Project Proponent seeking to issue against an improved carbon intensity must obtain a new verified EPD.

An EAC issued under this Protocol represents a quantified reduction against a Baseline. The Baseline is the carbon intensity of the counterfactual product that would have been used in the certified product's place, expressed in kg CO₂e per Functional Unit. This section sets how the Baseline is constructed, how it is updated over time, and how the Emission Reduction Value carried on each EAC is calculated.

Every EAC issued under this Protocol carries a Carbon Intensity, expressed in kg CO₂e per Functional Unit, together with a Baseline value, a Baseline type, and an Emission Reduction Value, as Certificate Attributes under Appendix D. This applies regardless of the claim type the Beneficiary uses at retirement.

The Baseline is selected using Table 3¹⁶. The Project Proponent applies the first row that fits at Validation, and reconfirms the selection at each Issuance.

Table 3. Baseline definition

The Baseline is updated over time. Update cadence depends on Baseline type. Table 4 sets out the update rules.

Table 4. Dynamic Baselines

A Baseline update takes effect at the next Issuance Review. When a new benchmark or new GCCA publication is released mid-Reporting Period, the update applies from the next Issuance Review onward. EACs issued at prior Issuance Reviews are not affected.

Where the Baseline is drawn from a source that publishes a range rather than a single value, for example the GCCA Low-Carbon Ratings Band D fallback, the Project Proponent must use the lower bound of the range as $CI_{Baseline}$ . The corresponding lower and upper bounds of the Emission Reduction Value are additionally recorded on the Registry for Buyer transparency.

An EAC is issued against the Baseline in effect at the Issuance Review at which the EAC is issued. When the Baseline is updated, previously issued EACs are not recalculated. Each EAC carries the Baseline value, Baseline type, and Baseline vintage in effect at its issuance as Certificate Attributes under Appendix D.

Each EAC carries an Emission Reduction Value calculated as the difference between the Baseline carbon intensity and the carbon intensity carried on the EAC. The Emission Reduction Value is the equivalent of the intervention outcome under the AIM Platform Standard¹⁸.

$$ERV = CI_{Baseline} - CI_{EAC}$$

Equation 2

Where:

• $ERV$ represents the Emission Reduction Value per Functional Unit, in kg CO₂e per Functional Unit.
• $CI_{Baseline}$ represents the Baseline carbon intensity per Section 8.4.1, in kg CO₂e per Functional Unit.
• $CI_{EAC}$ represents the carbon intensity carried on the EAC. This is the value reported per Section 8.1. Where Section 9.2.1 applies, the value is further adjusted by the uncertainty discount.

This section sets out the rules that apply to a Project relying on CCUS as a decarbonization pathway.

The following storage pathways for captured fossil and process CO₂ are default-eligible under this Protocol:

• Geological storage
• Mineralization, where the synthetic carbonated material meets the Long-Term Storage definition in Section 9.2

The following utilization pathways are eligible only where the Project Proponent demonstrates that the utilization meets the Long-Term Storage definition and MRV verification confirms that the bound CO₂ fraction stays bound over the relevant time horizon:

• CO₂-cured concrete
• CO₂-based chemicals

The following utilization pathways are excluded:

• Enhanced Hydrocarbon Recovery
• CO₂-based fuels, on the basis that the captured CO₂ re-enters the atmosphere when the fuel is combusted

Storage of captured CO₂ must be verified by an accredited Measurement, Reporting, and Verification (MRV) Protocol. The verified EPD for the certified product must reference the monitoring report produced under that MRV protocol for the CO₂ captured during the Reporting Period¹⁹. The monitoring report must identify the storage operator and site, state the injected quantity, describe the monitoring program, including how it detects reversals for closed-system storage, and confirm Long-Term Storage as defined in Section 9.2. Where the storage jurisdiction operates its own MRV Protocol, that protocol applies; where none exists, the MRV Protocol referenced must meet ISO-IWA 42:2022 (per Smart EPD Part B v4 Section Storage Verification)²⁰.

A separate Certificate of Storage document is not required where the MRV protocol output covers the fields set out above. Where a producer has already produced a Certificate of Storage in the format used by the GCCA Chain of Custody Rulebook²¹, that document may be submitted in lieu of a separate MRV output if it references an accredited MRV Protocol and covers the same fields.

The EPD VVB confirms the MRV reference at Validation. Where the EPD is verified against a regional PCR that does not cover CO₂ storage, the EPD VVB must additionally be accredited for the Smart EPD Part B v4 CCS add-on, or the Project Proponent must engage a second EPD VVB with that accreditation and cross-reference both verification statements. Where the EPD is verified against a regional PCR that does not cover CO₂ storage, the VVB must additionally be accredited for the Smart EPD Part B v4 CCS add-on, or the Project Proponent must engage a second VVB with that accreditation and cross-reference both verification statements.

Captured CO₂ must be stored in a form that qualifies as Long-Term Storage. Long-Term Storage is the definition applied by the local CO₂ storage regulatory body's MRV Protocol, or, where no such regulatory body or MRV Protocol exists, GWP100 per ISO-IWA 42:2022 (per Smart EPD Part B v4 Section: Long-Term Storage). Storage that does not qualify as Long-Term Storage is ineligible for EAC issuance. 

The Project Durability Threshold under this Protocol is 1,000 years, matching the default in Section 2.5.7 of the Isometric Standard. Every storage form eligible under this Protocol is expected to exceed 1,000 years, whether through geological permanence or through storage in the built environment, so a form that qualifies as Long-Term Storage but cannot demonstrate 1,000-year durability is not eligible under this Protocol. The Project Durability Threshold is recorded on the EAC as a Certificate Attribute.

The reversal-accounting route depends on whether the captured CO₂ is held in a closed-system or an open-system:

• Closed-system storage holds captured CO₂ in a monitored subsurface or engineered system, in which a Reversal is directly observable through the monitoring program required under Section 9.1. Geological storage, and captured CO₂ stored as carbonate mineral in a monitored subsurface or engineered system, are closed-system storage.
• Open-system storage holds captured CO₂ in a form in which a Reversal is not directly observable, for example CO₂-cured concrete, or captured CO₂ mineralized into aggregate or Supplementary Cementitious Material and incorporated into concrete.

The Project Proponent must also complete the Risk of Reversal assessment detailed in Appendix A, which categorizes The Project's Risk of Reversal. The Risk of Reversal category informs the monitoring program and the reversal risk treatment.

For closed-system storage, a Reversal is observable and is compensated after the event under Section 9.5. For open-system storage, the Risk of Reversal is "No observable risk" and reversal risk is instead accounted for as an uncertainty discount held inside the carbon intensity carried on the EAC, per Section 8 of Isometric's CO₂ Storage via Carbonation in the Built Environment Module. The mechanism is further set out in Section 9.2.1.

The verified EPD includes the stored CO₂ as a deduction within the reported carbon intensity. Under Smart EPD Part B v4, this credit is the verified Sequestered CO₂, being the quantity captured, measured, and verified by an independent third-party as put into geological storage or chemically bound through production of synthetic carbonated materials (Smart EPD Part B v4, Annex A). Should regional PCRs adopt CCS provisions, the same principle applies to whatever parameter that PCR uses to represent captured CO₂ credited as stored within the reported carbon intensity.

The Sequestered CO₂ is the deduction that drives the reported carbon intensity below the level it would carry without CCS. A Reversal releases that stored CO₂ back to the atmosphere. In an open-system a Reversal is not observable, so there is no event to compensate against after issuance, unlike closed-system storage under Section 9.5. The reversal risk is instead accounted for at issuance as an uncertainty discount that reduces the credited deduction, so the carbon intensity carried on the EAC is higher than the value reported on the EPD.

The uncertainty discount, its derivation, and the Project-specific reassessment procedure are set by Section 8 and Appendix A of Isometric's CO₂ Storage via Carbonation in the Built Environment Module. The Module models the fate of CO₂ stored in the built environment across the end-state uses cases, include but not limited to: construction, demolition, downcycle and reuse cycle over the 1,000-year durability horizon, accounting for the reversal mechanisms that apply to built materials, include but not limited to: exposure to low-pH fluids, fire, and high-temperature recycling. Under the Module's conservative scenario the modeled average loss at 1,000 years is 6% of the stored CO₂, which is the default discount (see details of the modelling and calculation for the default discount value in Section 8.2 of the Module). The discount is applied to the carbon intensity as:

$$CI_{EAC} = CI_{EPD} + (d \times M_{Stored})$$

Equation 3

Where:

• $CI_{EAC}$ represents the carbon intensity carried on the EAC, in kg CO₂e per Functional Unit.
• $CI_{EPD}$ represents the carbon intensity reported on the verified EPD, in kg CO₂e per Functional Unit.
• $d$ represents the uncertainty discount for open-system storage, expressed as a fraction. The discount is 6 percent (0.06) at the 1,000-year Project Durability Threshold. A Project Proponent may submit additional documentation to support a Project-specific reassessment of the discount, per that Module.
• $M_{Stored}$ represents the mass of fossil and process Sequestered CO₂ credited within the reported carbon intensity for the open-system pathway, in kg CO₂ per Functional Unit, excluding any biogenic share per Section 9.4.

The Emission Reduction Value per Section 8.4.3 is calculated using $CI_{EAC}$, so the discount flows through to a reduced Emission Reduction Value without further adjustment. The VVB confirms ​$M_{Stored}$ and the applied discount at Validation.

A Project Proponent may seek a discount other than the default by submitting an Uncertainty Discount Assessment, which produces a Project-specific model determination of reversal risk from submitted data, per Section 11.4 of the CO₂ Storage via Carbonation in the Built Environment Module. The evidence that may support a reassessment, and its effect on the discount, is limited to the documentation categories in Appendix A, Table A1.2 of the Module. The Assessment must identify the open-system pathway, being CO₂-cured concrete, captured CO₂ mineralized into aggregate, or captured CO₂ mineralized into a Supplementary Cementitious Material, and must characterize the applicable reversal mechanisms, such as exposure to the low-pH-fluid, fire, and high-temperature-recycling, because the fate profile differs across the pathways. A reassessment may lower or raise the discount. Where the submitted evidence demonstrates lower exposure than the Module's conservative scenario, the discount is reduced accordingly. Where the Project-specific model determination returns a higher expected loss, the discount is raised.

The VVB confirms $M_{Stored}$ and the applied discount at Validation. The discount is reconfirmed at each Surveillance Audit and reassessed at the renewal of the Crediting Period, or sooner where new scientific research materially changes the reversal-risk basis.

Emissions and fugitive leakage from CO₂ transport between the cement facility and the storage site must be included in the EPD's cradle-to-gate life cycle inventory for sequestration, LCI_seq, per Smart EPD Part B v4 Annex A. Any detected CO₂ Leakage during intermediate storage, transportation, or use must be reported and accounted for in the CCUS emission balance and made available at Issuance Review. This Protocol sets no separate transport-leakage cap; the requirement is that transport emissions and fugitive leakage are included in the carbon intensity value on the EPD, so they raise it by reducing the net stored CO₂ credited, and that value is what the EAC carries.

Biogenic CO₂ is treated as climate-neutral within the EPD for the product, per EN 15804+A2 and the GWP-biogenic separation applied by Smart EPD Part B v4. Biogenic CO₂ does not impact the carbon intensity or the Emission Reduction Value, and carries no reversal obligation under this Protocol.

The fossil and biogenic shares of the captured stream are determined by mass balance based on declared and verified carbon-bearing inputs, being fuel inputs and any carbonate feedstock inputs, per the applicable PCR. This applies to any CO₂ stream arising from the certified production process, however generated, including flue-gas capture and process-inherent separation such as indirect or electrochemical calcination. Where the mass balance is in question, for example under complex multi-fuel co-firing or a material inconsistency between declared inputs and observed operations, the VVB may require supplementary evidence, including isotopic (¹⁴C) verification of the captured stream per ISO 13833 or an equivalent standard.

Where biogenic CO₂ is durably stored, the storage may route to Isometric's Biogenic Carbon Capture and Storage (Bio-CCS) Protocol as a separate Carbon Dioxide Removal Certificate. Where the durably stored biogenic CO₂ does not meet those requirements, it is not credited as a removal and remains treated as climate-neutral within the EAC. Reversal risk for biogenic CO₂ credited as a removal is managed under the Bio-CCS Protocol. The rules governing parallel participation in this Protocol and the Bio-CCS Protocol, including the treatment of shared emissions and the prohibition on double-counting removals, are set in Section 9.6.

EACs issued under this Protocol make no Buffer Pool contribution. This follows the treatment of Environmental Attributes in Section 2.5.8 of the Isometric Standard: reversal risk for an EAC is managed through the reversal-compensation routes in this section and, for open-system storage, through the uncertainty discount in Section 9.2.1, not through a pool of withheld EACs.

• Closed-system CCS-backed EACs: the reversal is directly observable through the monitoring program required under Section 9.1, and is compensated after the event under this section.

• Open-system CCS-backed EACs: the reversal is not observable. Reversal risk is accounted for at issuance as an uncertainty discount on the credited stored CO₂ under Section 9.2.1, applied within the carbon intensity carried on the EAC. No further compensation applies.

• Non-CCS EACs: EACs relying on SCMs, kiln electrification, biomass fuel switching, or any other non-CCS pathway carry no Risk of Reversal and no reversal obligation.

A verified Reversal releases stored CO₂ that the verified EPD had credited as a deduction within the reported carbon intensity, per Section 9.2. Because that deduction is what lowered the carbon intensity, a Reversal means the carbon intensity carried on the affected EACs was lower, and their Emission Reduction Value higher, than the actual outcome, by the quantity of stored CO₂ released.

For closed-system storage, a verified Reversal is compensated through one of the following, depending on The Project:

• Projects under a recognized equivalent regulatory scheme: Where The Project operates within a regulatory scheme recognized as equivalent under Section 5.6.4 of the Isometric Standard, reversals from the qualifying storage reservoir are considered compensated through that scheme, and The Project makes no further compensation under this Protocol. The Project Proponent remains responsible for monitoring and reporting Reversals.
• All other Projects: A verified Reversal is compensated through Cancellation of the affected EACs, or from the Project's future issuances, per Section 5.6.1 of the Isometric Standard. The Reversal treatment, including the Avoidable and Unavoidable Reversal categorization and the treatment of a Project Proponent that ceases operations, follows that section.

The quantity of stored CO₂ released in a Reversal is converted into the number of EACs to be Canceled using the one-to-one relationship between stored CO₂ and Emission Reduction Value:

$$N_{Cancelled} = \frac{Q_{Reversed}}{ERV_{Unit}}$$

Equation 5

Where:

• $N_{Cancelled}$ represents the number of EACs Canceled to compensate for the Reversal, rounded up to the next whole EAC.
• $Q_{Reversed}$ represents the quantity of fossil and process stored CO₂ released in the verified Reversal, in tonnes CO₂, excluding any biogenic share per Section 9.4.
• $ERV_{Unit}$ represents the Emission Reduction Value one EAC represents, in tonnes CO₂e per EAC, being the Emission Reduction Value per Functional Unit determined under Section 8.4.3.

Rounding up is the conservative choice where the released quantity does not divide into whole EACs. EAC quantities are counted in Functional Units on the Registry, so Cancellation is in whole EACs. Because no pool is pre-funded, a Project not operating under a recognized equivalent regulatory scheme must secure continuity of the reversal obligation through the storage-operator-continuity dossier required at Validation under Section 9.7.

A Project relying on CCS where the captured stream is a mixture of biogenic and fossil CO₂ may participate in this Protocol and in the Isometric Bio-CCS Protocol in parallel. The routing of the captured stream between the two programs follows the origin of the CO₂, verified by mass balance:

• Fossil CO₂ captured and durably stored: Low Carbon Cement Protocol as an EAC.
• Biogenic CO₂ captured and durably stored: Isometric Bio-CCS Protocol, as a Carbon Dioxide Removal Certificate.

The Project Proponent must apply the routing on the basis of verified physical origin. Where the mass balance cannot cleanly apportion the captured stream, the Project Proponent applies the conservative fallback and routes the ambiguous share to neither program until the split can be verified. The mass-balance evidence rules that determine the fossil and biogenic shares are set in Section 9.4.

Removals must not be double counted. The same physical tonne of biogenic CO₂ captured and durably stored must not be credited under both this Protocol and the Bio-CCS Protocol. Emissions accounting may overlap across the two programs. Allocation rules for shared emissions between the two programs will be set in a future joint update to this Protocol and the Bio-CCS Protocol.

Article 6 international transfers under the Paris Agreement operate at the government level and are treated separately from Project-level EAC or Bio-CCS credit issuance. This Protocol takes no position on Article 6 accounting for the same underlying activity.

The storage operator responsible for injecting and monitoring the captured CO₂ is typically a separate legal entity from the cement producer. Continuity of monitoring and stewardship obligations across the operator's tenure is a condition of eligibility for a CCS-backed EAC.

The MRV Protocol reference required under Section 9.1 must identify the regulatory framework under which the storage site is permitted, and must identify the storage operator holding the permit for the Reporting Period. Where the storage jurisdiction operates a long-term stewardship regime that transfers monitoring obligations from the operator to the state or to a designated successor after a defined post-closure period, the MRV Protocol reference must name that regime.

Where the storage operator changes during a Reporting Period or a Crediting Period, the Project Proponent must record the change in the PDD and must submit updated permit and operator identification with the next Issuance Review. Isometric will confirm at Issuance Review that monitoring and stewardship obligations have transferred without gap. A handover recorded without a gap does not trigger a Reversal under Section 9.5.

Where the proposed storage jurisdiction has no operator-continuity framework, meaning no defined liability transfer regime and no long-term stewardship obligation on the operator, the Project Proponent must submit an additional dossier at Validation demonstrating that equivalent continuity outcomes are secured through contract or trust structures. The dossier must identify:

• the successor arrangement, being the storage jurisdiction's long-term stewardship regime where one exists, or contract or trust structures where none exists;
• the mechanism by which monitoring and stewardship obligations transfer to that successor without gap; and
• financial security sufficient to cover the maximum stored inventory over the post-closure period.

A Project operating under a recognized equivalent regulatory scheme relies on that scheme for continuity, including its financial-security requirement, and is not required to submit the dossier.

The Crediting Period is unchanged and is set under Section 11.5. After the Crediting Period ends, monitoring for Reversals continues for the duration required by the storage jurisdiction's long-term stewardship regime. Where the jurisdiction has no statutory stewardship regime, monitoring continues for 15 years after the end of the Crediting Period. Active monitoring during the Crediting Period is unchanged and follows the site MRV protocol and the Surveillance Audit cadence.

Stewardship of the storage site after The Project's Crediting Period ends is governed by the storage jurisdiction's regime, not by this Protocol. Safeguarding obligations that follow the operator handover are set out in Section 6.

The separation of an Environmental Attribute from its physical product introduces double counting risk. The cross-cutting framework that governs this exposure is set in Section 5.7 of the Isometric Standard, which aligns with the categories of double counting in ISO 22095-3:2026, and in Section 7.1 of the Book and Claim Module, which adds the multi-claim integrity rules, the residual mix framework, and the double disclosure safeguards. This section sets the cement-specific safeguards that operate in addition to that framework.

Once an EAC has been issued for the Environmental Attribute of a quantity of cement, concrete, or clinker, that Environmental Attribute has been separated from the physical product. The Physical Recipient of the de-attributed product must not make any quantitative claim about the carbon intensity or emissions reduction of that product, whether in a greenhouse gas inventory, a product or whole-building life-cycle assessment, a green-building rating scheme (for example LEED or BREEAM), or marketing. The statements the Physical Recipient may make are set in Section 10.2.

The Project Proponent must meet the following evidence requirements:

• The Project Proponent must provide the Physical Recipient the Baseline value and Baseline vintage recorded on the EAC under Section 8.4.2, being the conventional-cement benchmark used as the input to the Emission Reduction Value calculation in Section 8.4.3. The value and vintage provided to the Physical Recipient must be identical to those recorded on the EAC, not the benchmark current at the time of delivery, so that the Baseline the Physical Recipient reports and the Emission Reduction Value the Beneficiary reports trace to the same Baseline. This is the value the Physical Recipient reports, as set in Section 10.2.
• The Project Proponent must convey on the EPD for the product that the Environmental Attribute has been severed and issued as an EAC, and must state the Baseline value to be used²². A cover page accompanying the EPD is required in all cases. The Project Proponent must additionally record the declaration in the EPD notes field where the EPD program operator permits it, and set a status flag in the EPD database where the operator supports one. The notes field is required in addition to the cover page because it travels inside the EPD and survives separation from the cover page.
• The Project Proponent must reconcile EAC issuance against verified production at each Issuance Review, such that the EACs issued for a Reporting Period, plus any Environmental Attribute retained on physical product, do not exceed the verified production volume for that Reporting Period. This reconciliation is a quantitative control against over-issuance. As part of this reconciliation, Isometric, as Registry operator, confirms that the Baseline value and Baseline vintage on the EPD cover page match those recorded on the EAC.

The Environmental Attribute of a given quantity of certified product must not be credited both as an EAC under this Protocol and under any other crediting or certification program. The Project Proponent must declare at Validation every program through which the Environmental Attribute of its output is sold or credited, and must confirm at each Issuance that no quantity of certified production has been credited more than once.

The Physical Recipient is the party that takes delivery of the physical product after its Environmental Attribute has been severed and issued as an EAC. The Environmental Attribute does not travel with the physical product. It travels with the EAC, and the Beneficiary of that EAC is the party entitled to report it. The physical product carries the Baseline value and Baseline vintage recorded on the EAC, and that is the value the Physical Recipient reports.

The Physical Recipient may make qualitative statements about its use of the certified product and its experience with the producer, including publicising that it sourced the product from a named producer, that the producer is engaged in decarbonization, and that the product is a sustainable or low-carbon product, subject to any contractual disclosure and confidentiality terms. The Physical Recipient must not attach any figure to those statements. It must not state or imply a Carbon Intensity, an emissions reduction, a percentage improvement, or a GCCA Low-Carbon Rating band for the product, and must not use the product to support a quantitative entry in a greenhouse gas inventory, a product or whole-building life-cycle assessment, or a green-building rating scheme.

No residual mix calculation is required for EACs under this Protocol. This applies to both a market-wide residual mix and a per-product residual emission factor. 

Section 7.1.2 of the Book and Claim Module treats residual mix as a safeguard applied where the relevant Protocol requires it, reflecting that ISO 22095-3 permits the Requirements Setter to opt out where appropriate. This Protocol does not require a residual mix calculation because allocation under this Protocol is proportional only. Proportional allocation spreads the Environmental Attribute evenly across output, so there is no remainder within the Book and Claim Boundary from which Environmental Attributes have been concentrated, and therefore no residual to account for. A residual mix requirement arises only where a producer concentrates the Environmental Attribute onto a subset of output and leaves the rest behind. That is the non-proportional approach that SBTi V2 C27.4 and this Protocol does not permit.

A value-chain layer is a stage in the clinker, cement and concrete value chain at which the certified product enters an organization's own reporting. Section 5.4.1.1 of the Isometric Standard permits more than one organization to be named as a Beneficiary of a single Retirement, provided each claim is distinct and non-overlapping, and requires this Protocol to set the number of Beneficiaries permitted and the basis on which their claims are distinguished. Under this Protocol, co-claiming lets more than one organization along the cement value chain reflect the same EAC in its own reporting, with one claimant per value-chain layer and a maximum of four claimants. The cement value-chain layers are²³:

• Layer 1 - Production: The Project Proponent, being the clinker producer, cement producer, or ready-mix or precast concrete producer that issued the EAC. The EAC is a Scope 3 instrument for its Beneficiary and does not carry the Project Proponent's Scope 1 or Scope 2 reductions; the Project Proponent continues to report its own Scope 1 and Scope 2 emissions on its own inventory in accordance with the applicable framework.
• Layer 2 - Intermediate goods: The downstream producer that incorporates the certified product into a further product, being a cement producer using a clinker EAC or a concrete producer using a cement EAC.
• Layer 3 - Construction: The organization that purchases the certified product and incorporates it into a built asset under a construction contract. This is likely to be the main contractor, and may be a design-build contractor, an engineering, procurement, and construction contractor, or a subcontractor that purchases the product directly. An organization that specifies the certified product without purchasing it, for example an architect or an engineer on a services-only appointment, is not a Layer 3 claimant.
• Layer 4 - Asset ownership and use: The organization that procures the built asset or the works and reports the embodied emissions of the certified product in its own greenhouse gas inventory. This is likely to be the asset owner or the developer, and may be the tenant or occupant where the tenant or occupant, and not the owner, procured the works.

The primary Beneficiary can add co-claimants from other value-chain layers as additional Beneficiaries following their initial retirement. 

Co-claiming is permitted only between organizations occupying distinct and non-overlapping roles in the value chain. Where a single organization occupies more than one value-chain layer for a given EAC, for example a contractor that produces the concrete it installs, or an owner-occupier, it attaches at one layer only. Where the same reporting entity occupies more than one layer, those roles overlap, and a second attachment would count the same reduction twice within one greenhouse gas inventory.

Where two or more organizations could attach at the same layer, for example a main contractor and the subcontractor that purchased the concrete, only one may attach. The Beneficiary that retires the EAC determines which organization is added at that layer.

The stages of an EAC's life on the Isometric Registry are set in Section 5 (Crediting) of the Isometric Standard: Issuance, Delivery and Transfer, and end of life through Retirement, Expiry, or Cancellation. This section sets the cement-specific requirements at each stage.

An EAC is issued only after the physical low-carbon product has entered use. For clinker and cement the trigger is sale or shipment, whereas for concrete it is deployment²⁴. This prevents issuance against a product that is never sold or used.

The Project Proponent must provide evidence of sale or deployment at issuance. Acceptable evidence is a bill of landing, delivery ticket, invoice, or declaration of performance.

The interval between production and issuance must be as short as practicable. Section 3.4 of the Isometric Standard requires this Protocol to set the maximum period between production of the underlying product and the EAC issuance request. This Protocol sets no fixed maximum interval. 

An EAC issued under this Protocol carries the Certificate metadata for EACs defined in Section 5.1 (Certificate Attributes) of the Isometric Standard, plus the Protocol-specific attributes set out in Appendix D. All attributes are recorded on the Isometric Registry and are publicly visible, subject to the data restriction rules in Section 5.6.

This Protocol provides no conversion route between the clinker, cement, and concrete Functional Units, and Retirement for Conversion under Section 5.4.2 of the Isometric Standard is not available. An EAC remains at the Functional Unit against which it was issued, per Section 4, and must not be retired to enable issuance of an EAC at another Functional Unit.

This Protocol specifies no numeric conversion factors. The quantity and carbon-intensity relationships between clinker, cement, and concrete are captured within the EPD under the relevant PCR, and comparability between product types is governed by Buyer frameworks.

The primary flow of an EAC is downstream, from the Project Proponent toward the end user. Cross-claim direction and value-chain layer mechanics are set in Section 10.4.

An EAC issued under this Protocol must not be retired at the producer level to alter the producer's own product carbon intensity or EPD.

The activity generating the Environmental Attribute must be exclusively registered with the Isometric Registry, per Section 3.3 of the Isometric Standard. The same Environmental Attribute must not be issued, transferred, or retired on any other registry or crediting program²⁵. Inter-registry transfers are out of scope, aligned with Section 5.7.2 (Inter-Registry Operability) of the Isometric Standard. Isometric will coordinate with other registries to prevent cross-registry double counting and is open to pilot studies.

An EAC must be retired within 24 months of the end of its production vintage year, otherwise it expires. After expiry it can no longer be transferred or retired. This matches the default expiry period in Section 5.4.3 (Expiry) of the Isometric Standard.

The 24-month window applies the SBTi V2 Section C25.5 exception to the 12-month default. The justification is the cement and construction procurement cycle: cement is an input to multi-year construction programs, lead times between production, project award, construction, and buyer reporting can exceed 12 months, and there is no liquid spot market that would let Buyers time-match purchases precisely.

The maximum Crediting Period under this Protocol is 10 years. A validated Project may issue EACs for up to 10 years from Validation, subject to Issuance Review at each issuance request and to annual Surveillance Audits (Section 5.2). At the end of the Crediting Period, The Project must be re-Validated to continue issuing. 

The interventions this Protocol certifies, including kiln retrofits, carbon capture systems, and process electrification, are commissioned as long-duration assets, and a 10-year Crediting Period matches that investment horizon. Issuance Review of each issuance request and annual Surveillance Audits maintain integrity across the Crediting Period, so full re-Validation on an annual cadence is not required.

This section identifies the Buyer accounting frameworks under which a retired EAC issued under this Protocol is designed to be reported. Where a framework specifies how the EAC may be used, including substitution methods, matching rules, and any eligibility conditions, that framework's rules apply and the Protocol does not reinstate them.

An EAC issued under this Protocol is designed to be reportable under the major Buyer accounting frameworks. The framework a Beneficiary reports under determines how the EAC may be used and the entry it produces.

The Protocol's issuance-side integrity criteria are set at least as high as SBTi V2's, because SBTi V2 is the binding reference and imposes the strictest accounting criteria among the recognized frameworks. At a summary level:

• Under SBTi V2, an EAC supports a system contribution statement reported separately from the Buyer's physical inventory.
• Under the AIM Platform Standard V1.0, an EAC supports a Contractual Inventory entry or an Impact Statement.
• Under TCAT / MAARG V1.1, an EAC supports a Contractual Inventory entry or an Impact Statement within a Mitigation Action Report.
• Under the GHG Protocol Accounting for Market Instruments (AMI) (forthcoming), an EAC is expected to support entries into Statement 2 (market-based inventory) or Statement 3 (impact statement). This Protocol will be updated on AMI publication, per Section 3.

Buyer reporting is the responsibility of the reporting party under the applicable framework's rules. Isometric does not audit downstream reporting. The Beneficiary should apply the current version of the framework in force at the time of retirement, and should verify that the framework has not been superseded by an updated version.

Additionally, where the Beneficiary uses the Retired EAC as the basis of an impact statement under a recognised framework, the Beneficiary is responsible for any leakage assessment required by that framework. This Protocol does not assess leakage at issuance, and the Emission Reduction Value carried on the EAC reflects the certified product's cradle-to-gate GHG accounting boundary only.

This Risk of Reversal assessment applies to CCS-backed EACs only. It determines The Project's Risk of Reversal category, which informs the monitoring program and the reversal treatment under Section 9.5 for closed-system storage, and for open-system storage, confirms the "No observable risk" category under which reversal risk is accounted for as the uncertainty discount in Section 9.2.1. The Risk of Reversal category is recorded as a Certificate Attribute under Appendix D.

The assessment is completed at Validation and reconfirmed at each Surveillance Audit, and is reassessed where monitoring identifies a reversal-related risk, the storage technology materially changes, or a Reversal occurs, per Section 5.6 of the Isometric Standard.

The Project Proponent first confirms whether the captured CO₂ is held in closed-system or open-system storage, as defined in Section 9.2, because this sets the reversal-accounting route. The Project then completes the assessment for the applicable storage system type below.

A CCS-backed EAC Project should assess the following two factors under the project-specific-factors question in the Standard's questionnaire, being the question that adds to the Risk Score where one or more Project-specific factors merit a higher risk level:

1. Storage-operator continuity. Whether monitoring and stewardship obligations transfer without gap over the duration of storage, per Section 9.7. A storage jurisdiction with no liability-transfer or long-term-stewardship regime, or where continuity rests on the contract or trust structures permitted under Section 9.7 rather than a statutory regime, raises the Risk Score.
2. Carbonate mineral stability. For a pathway that stores captured CO₂ as carbonate minerals, the mineral phase and its thermal and acid stability, characterized under the mineralization verification in Section 9.1. A less stable carbonate phase raises the Risk Score.

The assessment will inform the monitoring program and the reversal treatment under Section 9.5. Where a Project operates under a regulatory scheme recognized as equivalent under Section 5.6.4 of the Isometric Standard, reversal compensation is provided by that scheme per Section 9.5; the category is still assessed and recorded.

The Project's Risk of Reversal is "No observable risk", per Section 2.5.8 of the Isometric Standard, which assigns open-system storage to that category because direct observation of a Reversal is not feasible. The Project does not complete the closed-system assessment above.

For these pathways reversal risk is accounted for as the uncertainty discount set out in Section 9.2.1, which sources the discount, its 6% default, and the Project-specific reassessment procedure from Section 8 and Appendix A of Isometric's CO₂ Storage via Carbonation in the Built Environment Module.

The discount is 6% of the stored CO₂ at the 1,000-year Project Durability Threshold (Section 8.3 of the CO₂ Storage via Carbonation in the Built Environment Module). The mechanics by which the discount is applied to the carbon intensity carried on the EAC are set in Section 9.2.1.

This Appendix reproduces the country-level GCCA Low-Carbon Ratings Band C and Band B thresholds applicable under Section 7.3, stated in kg CO₂e per tonne of cement. The Band C column applies to output produced from 2025 to 2029 and the Band B column applies to output produced from 2030 onwards; the column that applies to a given quantity of certified output is set by its production vintage, per Section 7.3. Values are as of January 2026 and Isometric will update this Appendix in step with subsequent GCCA updates. The country list is not exhaustive and countries not listed should use the global row.

Values are stated in kg CO₂e per tonne of cement. Source: GCCA Low-Carbon Ratings for Cement and Concrete; country values reproduced from Book and Claim for Cement and Concrete Appendix C, January 2026²⁶. Country-designated values apply where a country has adopted its own clinker-to-cement ratio applicable to the GCCA rating scheme.

This Appendix provides the clinker-equivalent translation tables referenced in Section 4. The tables let a Beneficiary express a cement or concrete EAC in clinker-equivalent terms for internal comparison or portfolio reporting across Functional Units. They are derived from the GCCA equivalence methodology (GCCA Rulebook Appendix 1.2: cement-to-clinker per A1.2.1, concrete-to-clinker per A1.2.2)²⁷.

The translation is a quantity translation only and expresses a number of EACs in tonnes of clinker-equivalent. It does not translate carbon intensities, Baselines, or Emission Reduction Values. A Beneficiary that wants to calculate an Emission Reduction Value per clinker-equivalent tonne divides the Emission Reduction Value on the EAC by the applicable translation factor.

A clinker-equivalent estimate must not be used for issuance, product matching, the emissions intensity threshold or any quantitative claim. Where no producer-specific data are available, the default factors in this Appendix apply the upper limit of the applicable standardized range, consistent with the GCCA Rulebook A1.2.1. Upper-limit defaults overstate the clinker content of blended cements, and therefore understate the Emission Reduction Value per clinker-equivalent tonne and overstate the clinker-equivalent quantity. The default is conservative for the first calculation and not for the second. A Beneficiary expressing a quantity in clinker-equivalent terms should use the producer-specific clinker content where the verified EPD discloses it. This is a further reason the estimate supports no claim.

One cement EAC is translated to clinker-equivalent tonnes by multiplying by the clinker-content factor of the declared cement type:

$$CE_{Cement} = N_{EAC} \times f_{Clinker}$$

Where:

• $CE_{Cement}$​ represents the clinker-equivalent quantity, in tonnes of clinker-equivalent.
• $N_{EAC}$​ represents the number of cement EACs, each representing one metric tonne of cement.
• $f_{Clinker}$ represents the clinker-content factor for the declared cement type, expressed as a fraction, determined below.

Where the verified EPD for the certified product, or other producer-specific verified data, discloses the actual clinker content, the Beneficiary should use that value as $f_{Clinker}$. Where no such data are available, the Beneficiary should apply the default factor in Table D.1, being the upper limit of the clinker-content range that EN 197-1 Table 1 and EN 197-5 permit for the declared cement type. A clinker EAC translates at a factor of 1.00. The clinker-content ranges in EN 197-1 Table 1 and in EN 197-5 are expressed as the sum of the main and minor additional constituents, with calcium sulfate and additives additional to that sum. A default factor applied to an EAC, which is denominated in one metric tonne of finished cement, therefore overstates clinker content by the calcium sulfate and additive fraction. The default factors are retained on this basis for comparability with GCCA Rulebook A1.2.1.

Table C.1. Default clinker-content factors by cement type

For cement certified under a United States product standard, the default factor is derived as follows:

• ASTM C150: The standard sets no clinker band that separates clinker from calcium sulfate and minor additions, so the default factor is 1.00, matching the CEM I treatment.
• ASTM C595: The type designation declares the nominal percentage of the non-clinker constituent, for example Type IL(10) or Type IS(35). The default factor is 1 minus the declared percentage expressed as a fraction. For a ternary Type IT cement, both declared percentages are deducted.
• ASTM C1157: The standard is performance-based and sets no composition limits, so no default factor can be derived. Producer-specific clinker content is required; absent it, the default factor is 1.00.
• Other national or regional standards: The default factor is the upper limit of the clinker-content range the standard permits for the declared type. Where the standard sets no such range, producer-specific data are required.

One concrete EAC is translated to clinker-equivalent tonnes in two steps, per GCCA Rulebook A1.2.2: the concrete volume is first translated to cement tonnage using a cement-content factor, and the resulting cement tonnage is translated to clinker-equivalent tonnes under the cement-to-clinker equivalence above.

A novel binder translates via its reference cement. The mass-equivalence factor assigned under Section 7.2.3, typically 1 to 1, converts the binder quantity to a quantity of the reference cement type, and Table C.1 then applies to that reference type, per GCCA Rulebook A1.2.3.

$$CE_{Concrete} = N_{EAC} \times c \times f_{Clinker}$$

Where:

• $CE_{Concrete}$​ represents the clinker-equivalent quantity, in tonnes of clinker-equivalent.
• $N_{EAC}$ represents the number of concrete EACs, each representing one cubic metre of concrete.
• $c$ represents the cement content of the concrete, in tonnes of cement per cubic metre, determined under this section.
• $f_{Clinker}$​ represents the clinker-content factor for the cement type used in the concrete.

Every concrete EAC issued under this Protocol carries a verified Environmental Product Declaration reference per Section 7.1, from which the cement content and cement type of the certified product are available. The Beneficiary should use those values for $c$ and $f_{Clinker}$​.

Where the translation concerns a product with no verified Environmental Product Declaration, for example a conventional inventory line the Beneficiary is comparing against, the Beneficiary should derive the cement content from a cited regional industry-average concrete Environmental Product Declaration matched to the strength and exposure class of the comparison product. No global default table is provided at this time. GCCA Rulebook A1.2.2 anticipates the publication of standardized cement-content factors; when those factors are published, they supersede this Section.

All EACs issued under this Protocol will carry the certificate metadata outlined in the Isometric Standard, as well as the cement-specific attributes set out below. 

The cement-specific attributes are grouped by the requirement each field operationalizes²⁸. Cross-references indicate the Section that sets the substantive rule.

Product identity

Carbon intensity and baseline

Pathway and lever

Additionality labels

Catalytic Impact

CCS-specific fields (for CCS-backed EACs)

Lifecycle and verification

Double claiming and Physical Recipient

Co-claiming

1. The three Functional Units are functionally equivalent to the eligible functional units in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 2.1. The GCCA Chain of Custody Rulebook v1.0 Section 3.2 instead defines a single clinker-equivalent functional unit; the translation between the two is set in Appendix C. ↩

2. Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 2.1, states that no standard currently exists to establish a consistent replacement rate for a Supplementary Cementitious Material in a verifiable or assurable manner. This Protocol adopts that position and routes Supplementary Cementitious Materials through the cement and concrete Functional Units in the interim. GMA and RMI have indicated a potential update on direct issuance for Supplementary Cementitious Material products. ↩

3. For details of planned updates to the Isometric Standard, refer to Appendix A of the Book and Claim Module ↩

4. This position was developed with reference to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 3.3, which sets no formal financial additionality requirement and relies instead on procurement-side screening. This Protocol departs in offering an optional enhanced pathway under which Financial Additionality is demonstrated through Internal Rate of Return analysis. ↩

5. The Regulatory Surplus test, the four Regulatory categories in Table 2, and the evidence requirements for each are applied directly from AIM Platform Standard V1.0, Appendix G. This Protocol does not restate or modify them. The disclosure-based structure is consistent with Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 3.2. ↩

6. This treatment is functionally equivalent to the clinker intensity measurement approach in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 4.1. ↩

7. The exclusion of Enhanced Hydrocarbon Recovery is functionally equivalent to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Sections 4.3 and 4.5, which bars Enhanced Oil Recovery from substantiating an emission reduction. This Protocol provides additional detail in permitting utilization pathways beyond mineralization where the Long-Term Storage definition in Section 9.2 is met, whereas that framework currently limits utilization to carbon mineralization. ↩

8. This exclusion is functionally equivalent to the qualitative primary-driver exclusion in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 3.3, which states that EACs should not be issued for blended cements or concretes where non-beneficiated or non-activated fly ash from coal-fired power plants or ground granulated blast-furnace slag represents the primary driver of emissions reductions relative to the appropriate baseline. This Protocol adds the Beneficiated and Activated definitions that determine when the exclusion is lifted. ↩

9. The reference-cement equivalence route for novel binders is applied directly from the GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0, Appendix A1.2.3. This Protocol adds the technical dossier and independent reviewer requirements that determine when equivalence is established. ↩

10. The band values are applied directly from the GCCA Low-Carbon Ratings for cement and concrete. This Protocol does not recalculate them. Anchoring the eligibility threshold to a GCCA band is functionally equivalent to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 3.1. This Protocol departs in setting a scheduled tightening from Band C to Band B by production vintage. ↩

11. The Catalytic Impact narrative was developed with reference to the catalytic procurement guidance in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 3.3, which directs procurement toward products requiring additional revenue to reach commercialization. This Protocol departs in making the narrative a mandatory disclosure at Validation rather than buyer-side guidance, to align with SBTi V2.0, and sets no absolute threshold. ↩

12. The CCS-specific accounting rules are applied directly from Smart EPD Part B v4, Product Category Rules for Construction Cements Standard 1000-010, including the CCS add-on. This Protocol does not restate or modify them. This follows Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Sections 4.3 and 4.4, in treating the captured CO2 as a deduction within the reported carbon intensity. The GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0 instead tracks stored CO2 in a separate ledger and adjusts the EPD value; this Protocol does not adopt that route. ↩

13. As defined in Section A.9.5 of the International EPD System's General Programme Instructions ↩

14. EPD International (2025) GENERAL PROGRAMME INSTRUCTIONS for the International EPD System Version 5.0.1 | Published on 2025-02-27. Available at: https://www.environdec.com/resources/general-programme-instructions ↩

15. Gross accounting with no adjustment for emissions trading system allowances is functionally equivalent to the treatment in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 4, and in the GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0. ↩

16. The principle that the Baseline is updated over time, and that the cadence follows existing industry cycles rather than a fixed period, was developed with reference to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 7. The differentiation of cadence by Baseline type in Table 4 is specific to this Protocol. ↩

17. A product-type shift occurs where the certified product's product type differs from that of the product the facility produced before the intervention. Product type means the cement type class of the certified product under EN 197-1 or EN 197-5, or the equivalent classification under ASTM C150, C595, C1157 or another recognized product standard. For a novel binder the product type is the reference cement type assigned under that pathway. For concrete, product type means the product form (ready-mix, precast or masonry) together with the compressive strength class and exposure class. A change in the product standard or certification route under which an equivalent product is certified is not a product-type shift, provided the certified product meets the same strength and exposure classes as the pre-intervention product and substitutes for it in the same applications. ↩

18. Emission Reduction Value is functionally equivalent to the intervention outcome in AIM Platform Standard V1.0. The two terms describe the same quantity and a Beneficiary reporting under that Standard may use the Emission Reduction Value carried on the EAC without adjustment. ↩

19. The monitoring report is the periodic report the storage operator produces by applying the applicable MRV Protocol, not the Protocol itself. Where the storage site is permitted under the EU CCS Directive (Directive 2009/31/EC), this is the report the operator submits to the competent authority under Article 14, covering the monitoring results required by Annex II. Where the site reports under the United States Greenhouse Gas Reporting Program, this is the annual report submitted under 40 CFR Part 98 Subpart RR against an EPA-approved MRV plan. Where neither applies, it is the equivalent report prepared under the MRV Protocol referenced at Validation. ↩

20. International Organization for Standardization (2022) IWA 42:2022 Net zero guidelines. International Workshop Agreement, first edition, November 2022. Available at no charge from ISO: https://www.iso.org/standard/85089.html ↩

21. The Certificate of Storage is defined in the GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0, Section 2.4. This Protocol does not require a Certificate of Storage but accepts one in lieu of a separate MRV Protocol output, so that a producer already transacting under that Rulebook is not required to produce a second document. ↩

22. The conveyance requirements are functionally equivalent to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Sections 8.1 and 8.2, which use the same three channels: the EPD notes field, a cover page, and a status flag in the EPD database. A producer transacting under both frameworks satisfies one set of requirements. ↩

23. The value-chain layer structure was developed with reference to the co-claiming provisions in the GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0, Section 4.2, and in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 6.4. This Protocol defines each layer by accounting relationship rather than entity type, and adds the within-layer election rule. ↩

24. The issuance trigger is functionally equivalent to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 5.1. ↩

25. This prohibition is functionally equivalent to Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 5.2, which requires that EACs are tracked on a digital registry and are not issued simultaneously on multiple registries. ↩

26. The country-level values in this Appendix are reproduced from Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Appendix C, which derives them from the GCCA Low-Carbon Ratings using country-specific clinker-to-cement ratios. This Protocol applies those values directly and does not recalculate them. Reproduced under CC BY-SA 4.0, https://creativecommons.org/licenses/by-sa/4.0/. ↩

27. The equivalence methodology in this Appendix is applied directly from the GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0, Appendix A1.2: cement-to-clinker per A1.2.1, concrete-to-clinker per A1.2.2, and novel binders per A1.2.3. This Protocol does not modify the methodology. The default clinker-content factors in Table D.1 are derived from the clinker-content ranges in EN 197-1 Table 1 and EN 197-5, applying the upper limit as the default consistent with A1.2.1. ↩

28. The cement-specific attribute set was developed with reference to the registry tracking requirements in Book and Claim for Cement and Concrete, Center for Green Market Activation and RMI, 2026, Section 5.2.2, and to the certificate data requirements in the GCCA Cement and Concrete Industry Chain of Custody Rulebook v1.0, Section 4.2. This Protocol carries additional fields required by its own rules, including Supplementary Cementitious Material contribution percentage, the Regulatory Additionality Category, and the open-system uncertainty discount. ↩