Protocol for Accounting and Reporting of
Avoided GHG Emissions through the Value
Chain of Cement and Cement-based Products
Ver. 1.0

March 2019

Taiheiyo Cement Corporation

Contents

Preface ............................................................................................................................................. 3
1

General..................................................................................................................................... 4
1.1

Purposes of the Protocol ................................................................................................... 4

1.2

Scope of the Protocol ........................................................................................................ 4

1.3

Structure of the Protocol .................................................................................................... 4

1.4

Developing Process of the Protocol and Referenced Guidelines and Standards ............ 5

1.5

Intended Users of the Protocol .......................................................................................... 6

1.6

Limitations of the Protocol ................................................................................................. 6

2

Terms and Definitions ............................................................................................................ 7

3

Principles ................................................................................................................................. 9

4

5

3.1

Basic Principles for Avoided GHG Emissions Accounting ................................................ 9

3.2

Application of Life Cycle Approach .................................................................................. 10

3.3

Mechanisms of Avoided GHG Emissions ........................................................................ 10

3.4

Trade-off........................................................................................................................... 11

3.5

Double Counting .............................................................................................................. 12

3.6

Allocation of Avoided GHG Emissions ............................................................................ 12

3.7

Methodological Framework for Accounting of Avoided GHG Emissions ........................ 13

Accounting of Avoided GHG Emissions ............................................................................ 14
4.1

Principles for Developing Accounting Methodologies for Avoided GHG Emissions ....... 14

4.2

Accounting of Avoided GHG Emissions .......................................................................... 15

Evaluation of the Avoided GHG Emissions Accounting Methodology and Accounting
Results .................................................................................................................................. 16

6

Reporting of Avoided GHG Emissions............................................................................... 18

Annex A Individual Methodology ............................................................................................... 20
Annex B ISO 14044 Reference Table ......................................................................................... 32

2

Preface
In accordance with the international framework adopted at the 21st Conference of the Parties to theUnited Nations Framework Convention on Climate Change (COP21), countries around the world aremaking efforts for greenhouse gas reduction. Japan sets a goal of 26.0% reduction by 2030 compared to2013, and this means that strong actions must be taken in each industry and at a corporate level.
Taiheiyo Cement (hereinafter referred to as “the Company”) has been part of these efforts, and as oneof its CSR Goals 2025, the Company has set a goal in greenhouse gas (hereinafter “GHG”) emissions
control and has been working on reduction in GHG emissions intensity through introduction of energy
saving equipment and efficiency improvement in kiln operation in cement manufacturing, and active
use of waste-derived and biomass-derived energy. As a result, net GHG emissions intensity in cement
manufacturing in 2017 was reduced by approximately 8% over the year 2000.
With this in mind, the Company has established an in-house cross-divisional organization and is
working for strategic consideration of GHG reduction technologies toward increased innovation in GHG
emissions control from a longer-term perspective. The work encompasses considerations into strategies
for accomplishing a drastic GHG emissions reduction never achieved in the past, not only with shortterm viewpoints but also with visions in longer-term perspectives especially in twenty or thirty years oftime. While the strategies for GHG emissions reduction certainly include direct emissions reduction
relevant to cement manufacturing, the strategies also explore, from the perspectives of cement value
chain, significant potential contributions which the Company’s products such as cement products,
concrete and others would be able to make on the stage of use by users. This means that in our efforts
to GHG emissions reduction, we will tackle direct emissions on one hand and at the same time we will
also work on GHG emissions reduction throughout the entire value chain including stages before andafter cement manufacturing, namely, avoided emissions.
The Protocol aims at GHG emissions reduction throughout the entire value chain specifically of
cement, and provides accounting methodology thereof. The Protocol covers avoided emissions bycement in general but shows a specific case study on accounting methodology of CO2 uptake which
represents a major part in the contribution by cement. Together with this, the Protocol also shows,
separately, accounting results obtained by the case study of the amount of CO2 uptake by cement
manufactured by the Company throughout its life cycle, demonstrating that contribution by cement issizable.
The Protocol is developed, as mentioned above, as a tool for the Company to move toward GHG
emissions reduction in terms of avoided emissions from the perspective of long-term global environment.
With this Protocol that we have developed, the Company will further promote its GHG emissions
reduction in cement and cement products, and at the same time will increase its efforts in development
and offering of the products which keep providing incremental contributions throughout the entire value
chain.

3

1

General

1.1

Purposes of the Protocol

Purposes of the Protocol include to provide a framework and methodology for quantification ofgreenhouse gas (hereinafter referred to as “GHG”) emissions reduced by cement and cement-based
products throughout their life cycles and in their value chain, and to promote development of consistentand highly transparent accounting method of the amount of the GHG emissions reduced by suchproducts (hereinafter “avoided GHG emissions”) throughout their life cycles and in their value chain,for increased use of those cement and cement-based products that feature enhanced level of sustainability.
There is no intention to use the Protocol for comparative assertion against related products from othercompanies.

1.2

Scope of the Protocol

The Protocol provides a framework and methodology for quantification of the avoided GHG
emissions in the entire value chain when cement and cement-based products are supplied to end users.
The protocol looks into the stage where the products are supplied to the end users because making
comparisons of intermediate products does not cover the entire product life cycle, and therefore does
not give realistic pictures about the avoided GHG emissions.
Avoided GHG emissions in the value chain is generally a result of contributions by all of the related
businesses involved in the value chain. However, there is no internationally accepted methods forallocating avoided emissions which are accomplished by respective stakeholders in the value chain.
There is also another difficulty that avoided GHG emissions are influenced by complexity of various
backgrounds and factors. Based on these, the Protocol only shows basic approaches toward the methodof allocating avoided GHG emissions to respective stakeholders in the value chain (see 3.6), but does
not give specifics.

1.3

Structure of the Protocol

The Protocol consists of a main part and annexes. The main part includes basic principles regarding
accounting of the avoided GHG emissions in the value chain of cement and cement-based products,
principles for developing accounting methodologies for avoided GHG emissions, and requirements inregard to evaluating and reporting the results of avoided GHG emissions accounting. The annexes
include an accounting methodology for avoided GHG emissions achieved by individual product orsolution, and others (Figure 1).

4Reference Standards:
ISO 14040 and ISO 14044
Basic Principles
for Avoided GHG
Emissions Accounting
Principles for Developing Accounting
Methodologies for Avoided GHG Emissions
Requirements for Evaluating and Reporting
the Results of Avoided GHG Emissions Accounting

Annexes: Individual Methodology, Recording Formats, etc.

Figure 1: Structure of the Protocol

1.4

Developing Process of the Protocol and Referenced Guidelines and Standards

The first draft of the Protocol was developed in 2018 based on discussions with representatives fromvarious relevant divisions in the Company and other specialists such as consultants, and then the final
version was completed after a review by an external certification body.
The first step in developing the Protocol was to determine items to be included and constituent
elements based on the following guidelines regarding accounting and reporting of avoided GHG
emissions.
<Referenced Guidelines in Determining Items to be Included and Constituent Elements of the Protocol>
Guidelines for Quantifying GHG emission reductions of goods or services through Global Value
Chain (Ministry of Economy, Trade and Industry (METI) of Japan, March 2018)
 Greenhouse Gas Protocol Product Life Cycle Accounting and Reporting Standard (World BusinessCouncil for Sustainable Development (WBCSD) and World Resources Institute (WRI), 2011)
 Guidelines--Accounting for and Reporting Greenhouse Gas (GHG) Emissions Avoided along theValue Chain based on Comparative Studies (WBCSD and International Council of Chemical
Associations (ICCA), October 2013)
 Accounting and Reporting Protocol for Avoided Greenhouse Gas Emissions along the Value Chainof Cement-based Products (Lafarge Holcim, January 2016)
 ISO 14064-2:2006 (JIS Q14064-2:2011) Greenhouse gases—Part 2: Specification with guidanceat the project level for quantification, monitoring and reporting of greenhouse gas emission
reductions or removal enhancements
The guidelines listed above constantly emphasize the importance of making evaluations from life
cycle perspectives of goods or services. Accordingly, the requirements in the Protocol consider theframework, principles and requirements of the following international standards (see Annex B ISO
14044 Reference Table for details).

5

<Standards Considered in the Development of the Protocol>
 ISO 14040:2006 (JIS Q14040:2010): Environmental Management—Life Cycle Assessment—
Principle and Framework
 ISO 14044:2006 (JIS Q14044:2010): Environmental Management—Life Cycle Assessment—
Requirements and Guidelines
The Protocol follows ISO wordings in the use of “shall”, “should” and “may”. Shall means mandatory,should means recommendation, and may means option depending on situations and necessities.

1.5

Intended Users of the Protocol

While the Protocol is intended for use within the Company, it is applicable to cement products ingeneral since it takes ISO 14040 and ISO 14044, or the two international standards, into account as
mentioned above, and nothing prevents any parties in the industry from using the Protocol. The Protocol
is expected to play a positive role in promoting contribution to quantification of avoided GHG emissions
in the cement industry, promoting product innovation utilizing quantified information about the avoided
GHG emissions, and improving reliability in avoided GHG emissions.

1.6

Limitations of the Protocol

Avoided GHG emissions accounting has limitations in its accuracy. A typical example can be tradeoffs in terms of environmental impacts which occur in the value chain perspective without being
recognized, leading to a biased evaluation of the product. Another example lies in accounting
coefficients utilized in avoided GHG emissions accounting. The values of the coefficients are based on
current results of studies, and must be replaced by those based on the latest results when avoided GHG
emissions accounting is made in the future.
Further, avoided GHG emissions in the value chain are generally a result of contributions by all of
the related businesses involved in the value chain. However, there is no internationally accepted methods
for allocating avoided emissions which are accomplished by respective stakeholders in the value chain.
In addition, avoided GHG emissions can be varied by a complexity of backgrounds and factors. Basedon these, the Protocol only shows basic approaches toward the method of allocating avoided GHG
emissions related to respective stakeholders in the value chain but does not give specifics. Allocation of
avoided GHG emissions to respective stakeholders in the value chain must be based on agreement to bereached in discussion process by parties including the stakeholders in the product life cycle.

6

2

Terms and Definitions

Definitions of the terms used in the Protocol are as follows:
Term
Definition/Description
Cut-off criteria
Specification of the amount of material or energy flow or the level ofenvironmental significance associated with unit processes or productsystem to be excluded from a study (JIS Q14044:2010). Criteria for
determining a process which will not to be subjected to inventory
analysis (example: a process having a minor impact). When setting thecriteria, considerations should be made in light of mass, energy andenvironmental significance.
Completeness check
Process of verifying whether information from the phases of a life cycle
assessment is sufficient for reaching conclusions in accordance with thegoal and scope definition (JIS Q14044:2010).
Sensitivity check
Process of verifying that the information obtained from a sensitivity
analysis is relevant for reaching the conclusions and giving
recommendations (JIS Q14044:2010).
Sensitivity analysis
Systematic procedures for estimating the effects of the choices maderegarding methods and data on the outcome of a study (JISQ14044:2010).
Reference flow
Measure of the outputs from processes in a given product system
required to fulfill the function expressed by the functional unit (JISQ14044:2010).
Functional unit
Quantified performance of a product system for use as a reference unit
(JIS Q14044:2010). (Example: For refrigerators, an amount of space(volume) to be cooled). Comparison throughout life cycle must be madeon the basis of an equal functional unit.
Critical review
Process intended to ensure consistency between a life cycle assessment
and the principles and requirements of the International Standards on life
cycle assessment (JIS Q14044:2010).
System boundary
Set of criteria specifying which unit processes are part of a productsystem (JIS Q14044:2010).
Consistency check
Process of verifying that the assumptions, methods and data areconsistently applied throughout the study and are in accordance with thegoal and scope definition performed before conclusions are reached (JISQ14044:2010).
Unit process
Smallest element considered in the life cycle inventory analysis for which
input and output data are quantified (JIS Q14044:2010).
Data validation
Confirmation of evidence that data quality requirements have been
fulfilled for the intended application during a process of data collection.
Validation may involve establishing mass balances, energy balances
and/or comparative analyses of emission factors (JIS Q14044:2010).
Allocation
Partitioning the input or output flows of a process or a product system
between the product system under study and one or more other productsystems (JIS Q14044:2010).

7

Value chain

Baseline
Life cycle assessment(LCA)
Life cycle inventory
analysis (LCI)

Avoided GHG
emissions

GHG emissions
intensity

An idea of understanding a series of business activities fromcollection/procurement of raw materials, throughmanufacturing/processing of products, transport, planning/marketing,sales, and after-sales service, to disposal, as a chain of values rather thana collection of individual processes. When used in the Protocol, the term
indicates the above-described series of business activities itself.
A scenario/status if the project in question is not implemented.
Compilation and evaluation of the inputs, outputs and the potential
environmental impacts of a product system throughout its life cycle (JISQ14044:2010).
Stage of life cycle assessment involving the compilation andquantification of inputs and outputs for a product throughout its life cycle(JIS Q14044:2010). In the Protocol, the term indicates, for example,
accounting of GHG emissions throughout a life cycle.
Quantified contribution to the GHG emission reductions which are
estimated throughout the life cycle GHG inventory of environmentallyfriendly goods or services in comparison to goods or services that
represent what is most likely to occur in the absence of assessed goods orservices (baseline scenario) (Guidelines for Quantifying GHG emission
reductions of goods or services through Global Value Chain, March
2018, METI of Japan).
GHG emissions per a given reference unit such as an amount of sales andan amount of production (Example: GHG emissions / Amount of sales;
GHG emissions / Amount of production).

8

3

Principles

3.1

Basic Principles for Avoided GHG Emissions Accounting

Avoided GHG emissions accounting shall be based on the five accounting principles (validity(relevance), completeness, consistency, transparency and accuracy) in the Greenhouse Gas Protocol.
The Protocol takes into consideration, as the sixth principle, “conservativeness” included in ISO 140642:2006 (JIS Q14064-2:2011) Greenhouse gases—Part 2: Specification with guidance at the project levelfor quantification, monitoring and reporting of greenhouse gas emission reductions or removalenhancements. Further, as the seventh principle, the Protocol takes into consideration “feasibility”
included in the Guidelines--Accounting for and Reporting Greenhouse Gas (GHG) Emissions Avoided
along the Value Chain based on Comparative Studies (October 2013, WBCSD and ICCA). These sevenprinciples serve as guidelines when performing accounting based on the Protocol, including cases where
the Protocol does not specify a relevant methodology.
The seven principles are summarized as follows:
Relevance

GHG emissions of a corporate shall be appropriately reflected in the GHG
inventory, so as to support decision making needs of the user--both inside andoutside of the corporate.
Completeness
All GHG emission sources and activities within the inventory boundary shall be
explained and reported. Disclose and justify any specific exclusions.
Consistency
Use consistent methodologies to allow for meaningful tracking of task-fulfillingcapability over time. Transparently document any time-series changes to thedata, inventory boundary, methods, or any other relevant factors.
Transparency
Address all relevant issues using factual and meticulous methodologies, basedon a clear fact-tracking investigations. Disclose any relevant assumptions andmake appropriate references to the accounting and calculation methodologies
and data sources used.
Accuracy
Ensure that the quantification of GHG emissions is systematic, neither over nor
under actual emissions as far as can be judged, and that uncertainties are
reduced as far as practicable. Achieve sufficient accuracy to enable users tomake decisions with reasonable assurance as to the integrity of the reported
information.
Conservativeness Use conservative assumptions, values and procedures to ensure that GHG
emission reductions or removal enhancements are not over-estimated.
Feasibility
Ensure that the chosen approach can be executed within a reasonable timeframe
and at reasonable effort/cost.
Sources: Japanese translation (by Ministry of the Environment and METI of Japan) of the Technical Guidance for
Calculating Scope 3 Emissions - Supplement to the Greenhouse Gas Protocol Corporate Value Chain(Scope 3) Accounting & Reporting Standard (WBCSD and WRI); ISO 14064-2:2006 (JIS Q14064-2:2011)
Greenhouse gases—Part 2: Specification with guidance at the project level for quantification, monitoring
and reporting of greenhouse gas emission reductions or removal enhancements; and Guidelines-Accounting for and Reporting Greenhouse Gas (GHG) Emissions Avoided along the Value Chain basedon Comparative Studies (October 2013, WBCSD and ICCA).

When accounting avoided GHG emissions, purposes of the accounting should be clearly set first ofall. When setting the purposes, clearly describe intended use, reasons for making the accounting, andintended target of communication.

9

3.2

Application of Life Cycle Approach

As described in 1.4, the Protocol makes use of the framework and principles from two standards
regarding LCA, specifically from ISO 14040:2006 (JIS Q14040:2010): Environmental Management—Life Cycle Assessment—Principle and Framework; and from ISO 14044:2006 (JIS Q14044:2010):
Environmental Management—Life Cycle Assessment—Requirements and Guidelines. The frameworkof LCA helps appropriate grasping of avoided GHG emissions from the viewpoint of product life cycle.
LCA consists of four stages, i.e., setting goal and scope of study, inventory analysis, impact evaluationand interpretation.
3.3

Mechanisms of Avoided GHG Emissions

Table 1 shows a summary of categories and mechanisms of avoided GHG emissions of cement andcement-based products from the life cycle viewpoint.
Table 1: Summary of Mechanisms of Avoided GHG Emissions by Cement and Cement-based
Products
Large
No.
No.
Middle Category
Mechanisms of Avoided GHG Emissions
Category
A Mining
1 Raw material
 Efficient mining process of raw materials
process
miningreduces GHG emissions in comparison toconventional mining process.
2 Preservation of Preservation of mining sites (e.g., treemining sites
planting) after completion of mining creates
CO2 absorption effect.
B Manufacturing
1 Raw material
 In manufacturing process, procurement ofprocess
procurement
raw materials which have low GHG
emissions intensity reduces GHG emissions
at the procurement sources.
2 Transport Efficient or innovative transport process
reduces GHG emissions.
3 Manufacturing
 Manufacturing process which has high GHG
emissions control effect reduces emissions.
 Use of recycled materials and/or recycled
thermal energy sources reduces productioninduced emissions.
C Construction
1 Transport Efficient or innovative transport processprocess
reduces GHG emissions.
2 Construction and In construction and repairing of structuresinstallation
and buildings, active use of materials whichenable efficient construction and repair
reduces direct and indirect emissions related
to the construction. Further, shortened
construction period will reduce the amountof related tasks and materials, leading to
additional emissions reduction.

10

No.
D

E

Large
Category
Use process

DisposalprocessF

Others3.4

Trade-offNo.

Middle Category

1

Use

2

Maintenance, repair,
replacement andrenovation

1

Demolition andtemporary storage

2

Transport

3

Waste treatment

1

Reuse and recycling

Mechanisms of Avoided GHG Emissions
 During the use stage of buildings or the like,materials which, for example, have superior
heat insulation reduce the amount of energy
necessary for heating/air conditioning.
 During the use stage of cement and cementbased products, CO2 absorption effect takes
place as these products undergo carbonation.
 Use of materials and products superior instrength/durability reduces GHG emissions(through extended durable life for example)
arising from new construction work ofstructures and buildings, and fromproduction/use of necessary materials.
Decreased frequency in maintenance/repair
also reduces GHG emissions relevant to thework and materials.
 Active use of materials and diagnostic
technologies which enable efficientmaintenance and repair reduces need forrelevant work and materials, and therefore
reduces GHG emissions.
 Efficient demolition process reduces GHG
emissions over conventional demolition
process.
 During the stage of demolition andtemporary storage of cement-based products,
CO2 absorption effect takes place as theseproducts undergo carbonation.
 Efficient or innovative transport process
reduces GHG emissions.
 Efficient and effective waste treatment
process reduces GHG emissions overconventional treatment process.
 Through reuse and recycling, manufacture of
new products and GHG emissions caused by
the manufacturing process are avoided.

In general, LCA is effective in understanding trade-offs between various impacts on the environment
since it takes various environmental impacts into account throughout the product life cycle. The Protocol
makes use of the framework and principles of LCA with special focus on impacts onto climate changes,
and more specifically onto GHG emissions and avoided GHG emissions. While it is anticipated that
reduction in GHG emissions will basically not cause serious negative impact on other environmental
indicators (e.g., discharge of waste, and water resources), it is necessary, when accounting avoided GHG
emissions, to see if there is any possible trade-offs in terms of environmental impact. If the accounting
detects any possible trade-offs, environmental impacts from them shall also be reported.
11

3.5

Double Counting

The subject of the Protocol is accounting of avoided GHG emissions from cement and cement-based
products throughout their value chain. For this reason, there can be cases where, for example, the amountof GHG emissions reduction in the product manufacturing process is counted in both of the reporting of
Scope 1 emissions and the reporting of avoided GHG emissions; namely, double counting can take place
between the two. Double counting can also occur when accounting the scope 3 emissions. Since theentire value chain of the product is the subject in both of the accounting of avoided GHG emissions andthe accounting of the scope 3 emissions, there can be double counts between the two.
It is necessary to explain all of these double counts in avoided GHG emissions accounting. GHG
emissions at the corporate level and avoided GHG emissions at the product level shall be distinguishedfrom each other, and any possible double counts shall be disclosed in reporting of the accounting results.
Still another area of possible double counting is avoided GHG emissions by related business entities
in the value chain. A plural number of related parties in the value chain may claim for a certain amountof avoided GHG emissions as their own contribution. Handling methods of these problems are provided
in 3.5. Setting rules on how to allocate avoided GHG emissions to the related parties in the value chain
is useful to avoid double counting but is not in the scope of the Protocol as stated in 1.6.
Another chance for double counting is when avoided GHG emissions by one product is accounted inplural categories of avoided GHG emissions. Annex A provides a methodology for individual
accounting categories of avoided GHG emissions. Avoided GHG emissions of a product shall be
evaluated only in one category of avoided GHG emissions.

3.6

Allocation of Avoided GHG Emissions

Avoided GHG emissions of a product are a sum of activities of a plural number of business entities
in the value chain (e.g., raw material suppliers, product manufacturer, and users of the product). In mostcases the scope lies beyond the range controllable by any single business entity (e.g., productmanufacturer). For example, at the use stage of a building, energy saving effect is a sum of activities not
only by the product manufacturer but also the owner and users of the buildings.
However, there is no internationally accepted methods which are capable of allocating avoided
emissions to each of the business entities in the value chain.
While the Protocol does not show details for methodologies to allocate avoided GHG emissions to
individual entities in the value chain, directions thereof are provided in the Guidelines--Accounting for
and Reporting Greenhouse Gas (GHG) Emissions Avoided along the Value Chain based on
Comparative Studies (October 2013, WBCSD and ICCA). The Guidelines provide, as shown in Table
2, contribution levels in value chain avoided emissions and basis in determining the levels. The reporting
corporate shall report a total amount of avoided emissions in the entire value chain, and also report about
the levels of contribution of the product with respect to the final product in accordance with Table 2.
Further, the reporting corporate shall describe specific part that their product plays and how it relates tothe avoided GHG emissions of the final product, clearly in a way the readers can comprehend.
Table 2: Contribution Levels in Value Chain Avoided Emissions by Chemical ProductContribution Level
Relationship between Chemical Product and Final ProductThe chemical product is the key element that enables the avoided GHG
Fundamental
emissions by the use of the final product.
The chemical product is part of the key element and its properties/functions
Extensiveare essential for enabling the avoided GHG emissions by the use of the final
product.
12

Substantial

Minor
Too small tocommunicate

The chemical product does not contribute directly to the avoided GHG
emissions, but it cannot be substituted easily without affecting the avoided
emissions by the final products.
The chemical product does not contribute directly to the avoided GHG
emissions, but it is used in the manufacturing process of a fundamentally or
extensively contributing product.
The chemical product can be substituted without affecting the avoided GHG
emissions by the final products.

Source: Guidelines--Accounting for and Reporting Greenhouse Gas (GHG) Emissions Avoided along the Value
Chain based on Comparative Studies (WBCSD and ICCA, 2013).

3.7

Methodological Framework for Accounting of Avoided GHG Emissions

Based on the mechanisms of avoided GHG emissions (see 3.3), the Protocol provides amethodological framework for avoided GHG emissions accounting as shown in Table 3.
Table 3: Methodological Framework for Accounting of Avoided GHG Emissions
No.
Large CategoryNo.
Middle Category
A Mining process1
Raw material mining
2
Preservation of mining sites
B Manufacturing process1
Raw material procurement
2
Transport
3
Manufacturing
C Construction process
1
Transport
2Construction and installation
D Use process1
Use2
Maintenance, repair, replacement and renovation
E Disposal process1
Demolition and temporary storage
2
Transport
3
Waste treatment
F Others
1
Reuse and recycling

13

4

Accounting of Avoided GHG Emissions

4.1

Principles for Developing Accounting Methodologies for Avoided GHG
Emissions

Methodologies for accounting avoided GHG emissions shall describe all definitions, assumptions andrules necessary for accounting avoided GHG emissions throughout the product life cycle. Consistency
should be ensured within the scope of the Protocol throughout all of the avoided GHG emissions
accounting methodologies. Table 4 lists the contents which should be included in the accounting
methodologies for avoided GHG emissions:
Table 4: Contents which Should be Included in Accounting Methodologies for Avoided GHG
EmissionsNo.
Major Item
Intermediate Item
Content
1 Name of methodology
N.A.
Write the name of the methodology.
2 Definitions of terms
N.A.
Write the definitions of terms used in
the methodology.
3 Levels in the value chain / Explanation
Describe the purposes and summary
System boundary /of the methodology.
Coverage of accounting
Functions and functional Describe functions and functional
and target processes /units
units (see 2. Terms and Definitions).
Mechanisms of avoided
System boundary,
Describe system boundary, coverage
GHG emissions
coverage of accounting, of accounting and target processes,
and target processes
and rationales and/or basis thereof.
Any exclusions shall be accompanied
by description on their impacts on the
conclusion (e.g., amount of avoided
emissions) and reasons for the
exclusion.
Service life / Durable
Describe service life / durable life oflife
the goods or services in thefunctional unit, and rationales for theservice life / durable life.
Time and geographical
Describe the time and geographicalreferencesarea selected as the basis of thestudy.
Baseline
Describe information about thebaseline (see 2. Terms andDefinitions).
Mechanisms of avoided Describe mechanisms of how GHG
GHG emissions
emissions are avoided.
Flow of unit process,Describe the flow of unit process (seeand input and output
2. Terms and Definitions), andthereofinput/output thereof.
4 Accounting method
General information and Provide general information about
outline of accounting
avoided GHG emissions accounting
methodology, and list databases andothers used in the study.

14

No.

Major Item

Intermediate Item
Estimations andassumptions

Cut-off criteria
Allocation

Mathematical formulae

Data sources

References

Others

4.2

Content
Provide information about
estimations and assumptions if
included in the accounting
methodology.
Describe cut-off criteria (see 2.
Terms and Definitions).
Describe methods of allocation (see2. Terms and Definitions) if
allocation is needed.
Provide mathematical formulae foravoided GHG emissions accounting
based on the appropriate flow of theunit process.
List sources and rationales forcoefficients and other values used in
the accounting.
List reference documents and otherliterature used in the development ofaccounting methodology.
Describe, for example, further
procedures to convert indicators
obtained as a result, referencematerials selected, and rationales forweighing coefficients and others.

Accounting of Avoided GHG Emissions

From the avoided GHG emissions accounting methodologies developed on the principles in 4.1, selectan appropriate methodology in terms of the avoided emissions accounting category, and perform an
accounting by following the selected methodology. Data which are collected for the accounting shall be
subjected to data validation in order to ensure that data quality requirements are met for the intended
use.

15

5

Evaluation of the Avoided GHG Emissions Accounting Methodology andAccounting Results

Evaluation shall be performed in consideration of three methods listed in Table 5 in order to establish
and enhance credibility and reliability of the results of the avoided GHG emissions accounting.
Table 5: Evaluations to be Performed in the Developing Process of Avoided GHG Emissions
Accounting Methodology and the Accounting Process
No.
Major Item
Content
1 Completeness check Process of verifying whether information from the phases of a life
cycle assessment is sufficient for reaching conclusions in accordancewith the goal and scope definition (JIS Q14044:2010).
2 Sensitivity analysis / Sensitivity analysis: Systematic procedures for estimating the effects
Sensitivity checkof the choices made regarding methods and data on the outcome of astudy (JIS Q14044:2010).
Sensitivity check: Process of verifying that the information obtained
from a sensitivity analysis is relevant for reaching the conclusions andgiving recommendations. Sensitivity check shall consider thefollowings (JIS Q14044:2010):
 Items predetermined by the goal and scope of the study
 Results obtained from all the other stages of the study Professional judgments and past experiences
3 Consistency check
Process of verifying that the assumptions, methods and data areconsistently applied throughout the study and are in accordance withthe goal and scope definition performed before conclusions arereached. The following questions shall be addressed in theconsistency check (JIS Q14044:2010):
 Are differences in data quality along a product system life cycle
and between different product systems consistent with the goal andscope of the study?
 Have regional and/or temporal differences, if any, been consistently
applied?
 Have allocation rules and the system boundary been consistently
applied to all product systems?
 Have the elements of impact assessment been consistently applied?
The avoided GHG emissions accounting methodology and the avoided GHG emissions accounting
results shall be subjected to critical review as a principle. Processes of the critical review shall ensure
the followings:
 Methods utilized in performing the LCA confirm to JIS Q14044:2010 and the Protocol.
 The methods utilized in performing the LCA are scientifically and technically valid.
 Utilized data are pertinent and reasonable in the light of goal of the study.
 Interpretations reflect the specified limitations and the goal of study.
 The study report has transparency and consistency.

16

The critical review may be performed by internal or external professionals. In this case, the reviewing
professionals shall be independent from the LCA. Further, the review may be made by interested parties.
In this case, the reviewer should be selected from external independent professionals. The critical review
should be performed by those knowledgeable in LCA, GHG emissions and avoided GHG emissions
accounting, and cement-based products. Record shall be made for determinations on the scope and typeof the critical review.
If the critical review is not performed, reasons or grounds therefor shall be expressly described.

17

6

Reporting of Avoided GHG Emissions

Since avoided GHG emissions represent the amount of avoided emissions throughout the entire value
chain, it is not possible to subtract the avoided emissions from a corporate level GHG inventory (scope
1, 2 and 3 emissions). Therefore, reporting of avoided GHG emissions shall be made separately from
corporate-level external reporting (scope 1, 2 and 3 emissions) which follows, e.g., the Greenhouse Gas
Protocol. Table 6 lists items required in the reporting.
No.
1
2

3

4

5

Table 6: Items Required in Reporting of Avoided GHG Emissions
Major Item
Intermediate Item
Outline of GHG avoided emissions
Methods of GHG avoided emissions
Levels in the value chain / System
Description
boundary / Coverage of accounting andFunctions and functional units
target processes / Mechanisms of avoided
System boundary, and coverage of accounting
GHG emissions
and target processes
Service life / Durable life
Time and geographical references
Baseline
Mechanisms of avoided GHG emissions
Flow of unit process, and input and output
thereof
Accounting method
General information and outline of accounting
Estimations and assumptions
Cut-off criteria
Allocation (if allocation was required)
Mathematical formulae
Information regarding parameters
Data sources (sources and rationales forcoefficients and others)
Data quality (Describe handling rules formissing data, if any.)
Others
Evaluation
Completeness checkSensitivity check
Consistency check
Life cycle interpretation
The results; assumptions and limitations
associated with the interpretation of results,
both methodology and data related; data quality
assessment; and full transparency in terms ofvalue-choices, rationales and expert judgments

Source: The table was developed with reference to the Guidelines--Accounting for and Reporting Greenhouse Gas(GHG) Emissions Avoided along the Value Chain based on Comparative Studies (WBCSD and ICCA,
2013).

18

References of the Protocol―――――――――――――――
 Accounting and Reporting Protocol for Avoided Greenhouse Gas Emissions along the Value Chainof Cement-based Products (Lafarge Holcim, January 2016)
 ISO 14040:2006 (JIS Q14040:2010): Environmental Management—Life Cycle Assessment—
Principle and Framework
 ISO 14044:2006 (JIS Q14044:2010): Environmental Management—Life Cycle Assessment—
Requirements and Guidelines
 ISO 14064-2:2006 (JIS Q14064-2:2011) Greenhouse gases—Part 2: Specification with guidanceat the project level for quantification, monitoring and reporting of greenhouse gas emission
reductions or removal enhancements
 Greenhouse Gas Protocol Product Life Cycle Accounting and Reporting Standard (WBCSD and
WRI, 2011)
 Guidelines for Quantifying GHG emission reductions of goods or services through Global Value
Chain (METI of Japan, March 2018)
 Guidelines--Accounting for and Reporting Greenhouse Gas (GHG) Emissions Avoided along theValue Chain based on Comparative Studies (WBCSD and ICCA, October 2013)19

Annex A Individual Methodology
A-1 A methodology for accounting CO2 uptake by cement [target processes in the value
chain: D-1, E-1 and F-1 in Table 1]
1. Name of methodology
Accounting of CO2 uptake by cement
2.

Definitions of terms

Terms
Portland cement

Blended cement
Clinker

Cement-basedsolidifying material
Carbonation

Degree ofcarbonation
Unit cement
content
Equivalent surfacearea
Subbase material

Waste concretemass
Recycled crushed
stone

Definitions
Cement manufactured by grinding clinker which mainly consists of hydrauliccalcium silicate with addition of an appropriate amount of gypsum. Cement
which is generally specified in JIS R5210.
Portland cement pre-mixed with mineral admixture such as groundgranulated blast furnace slag.
Nodular material produced by burning the raw materials (limestone, clay,
silica stone, iron material, etc.) in a rotary kiln at a high temperature around
1,450°C.
General term for soil stabilizers consisting mainly of cement which are used
to solidify soil for the purpose of improving mechanical and chemical
properties of the soil.
Phenomenon in which hardened concrete gradually loses its alkalinity underthe effects of atmospheric carbon dioxide and others. Unlike the term
"neutralization", the term in this accounting methodology means carbonationof concrete due to the effect of carbon dioxide.
Ratio (in moles) of CaO contained in cement which transforms to CaCO3 due
to carbonation (forming CaCO3).
Amount of cement per 1 m3 of concrete (kg/m3).
Surface area of a structure or building specified to determine the volume of
concrete carbonated during the use stage, which is calculated by dividing thetotal volume of concrete used with an average thickness of the members.
Material used for the layer which distributes and transfers the load fromasphalt mixture layer or concrete slab to the roadbed. Examples include
crushed stone for road construction use produced by breaking rock andrecycled crushed stone produced by breaking waste concrete mass and others
occurring from demolition of buildings.
Concrete waste in a massive form occurring from demolition or the like ofconcrete structures and buildings.
Recycled aggregate obtained by crushing and mechanically stabilizing waste
concrete mass or other waste materials.

20

3.

Levels in the value chain / Coverage of accounting and target processes / Systemboundary(1) Explanation
The cement after production and sales is mainly used in concrete for buildings and structures. They
are demolished after a given use stage and reused as recycled crushed stone for, for example, subbase
material and backfilling material (Figure 7.1-1). This methodology aims at CO2 uptake by cement atthese life cycle stages.
供用期間
Use
stage
(severalten years)（数十年）

Structures and〔構造物･建築物供用〕
buildings in service

Demolition and解体･仮置期間
temporary storage stage(several days
to several months)（数日～数ヶ月）

Recycled crushed stone〔再生砕石 仮置き〕
in temporary storage

Demolition
〔解体〕

再利用期間
Reuse
stage
(severalten years)（数十年）

Subbase〔路盤材等〕
material, etc.

Figure 7.1-1: Life Cycle of Cement Products
Cement and cement-based products produced at cement plants include portland cement, blended
cement, clinker and cement-based solidifying material. In this CO2 uptake accounting methodology(hereinafter “this methodology”), accounting shall be made with proper consideration given to
impacts of each product on the CO2 absorption.
In addition, portland cement is available in several types, including ordinary portland cement, highearly strength portland cement and moderate heat portland cement, and there are also various typesof blended cement such as portland blast furnace slag cement and portland fly ash cement. Influenceof these cement types on CO2 absorption shall be also taken into account in accounting properly.
Table 7.1-1: Types of Cement and Cement-based Products and CO2 Uptake Accounting Categories
Types
Categories for CO2 uptake accounting
Portland cement
Blended cement
Clinker
Cement-based solidifying material
The period of time shall be properly specified for each stage of use, demolition and temporarystorage, and reuse. The period of the use stage is generally a period during which a structure orbuilding is in service after completion of construction. The period of the demolition and temporarystorage is a period during which the structure or building is demolished and stored until the recycling
stage. The period of the reuse stage is a period during which the demolished concrete is reused asrecycled crushed stone for subbase material or other applications.

21

(2) Explanation about function and functional unit
The function is expressed by the amount of cement produced within one year, used in buildings or
structures and, after the use stage, demolished and reused* within the coverage of accounting (specificcement plant(s), inside or outside the country, etc.), or, an appropriate range or functional unit
(category or amount of cement, etc.) of the goods/services to be evaluated.
*reused as recycled crushed stone for subbase material or backfilling material(3) System boundary, coverage of accounting, and target processes
Figure 7.1-2 shows the system boundary, the coverage of accounting, and the target processes. The
coverage of accounting covers a series of processes in which cement is used in buildings or structures
for a given use stage, demolished and temporarily stored, then reused as recycled crushed stone forsubbase material and backfilling material.
System boundary
Miningprocess

Manufacturing
process

Construction
process

Use process

Disposalprocess

Other process

Raw material
miningRaw material
procurement

Transport

Use

Demolition
and temporarystorage

Reuse andrecycling

Transport

Construction
andinstallation

Maintenance,
repair,replacement
and renovation

Preservationof mining
sites

Waste
treatment

Manufacturing

Explanation

Existing processes

Transport

Target processes

Figure 7.1-2: System Boundary, Coverage of Accounting, and Target Processes(4) Service life / Durable life Use stage
Carbonation of concrete depends on the time length of exposure to the atmosphere. The use stage
which actually varies by the type of structures and buildings shall be specified based on the principleof conservativeness described in 3.1 Basic Principles for Avoided GHG Emissions Accounting in themain part.
 Demolition and temporary storage stage
Generally, concrete structures and buildings are demolished after their use stage on site into waste
concrete masses sized several ten centimeters or smaller. They also contain fine particles of several
millimeters to powdery sizes. The waste concrete mass is transported to an intermediate processor
and refined there into recycled crushed stone through the processes like crushing by crushers andparticle size classification using sieves. After a certain period of storage at a storage yard of theintermediate processor, the recycled crushed stone is transported to its destination and reused for22subbase material or other applications. The demolished concrete during this period absorbs CO2 in
the atmosphere as it is in a massive or granular to powdery form with small particle sizes and exposedto the external air for a certain period of time.
The demolition and temporary storage period shall be specified based on the principle ofconservativeness.
 Reuse stage
The reuse stage is a period during which the demolished concrete is reused as recycled crushedstone for subbase material or other applications. CO2 uptake during the reuse stage is considered tobe minor because the recycled crushed stone is used under compacted condition in lower layers of theroad surface covered with asphalt or concrete upper layers, having practically no contact with theatmosphere. The reuse stage shall be specified based on the principle of conservativeness describedin 3.1 Basic Principles for Avoided GHG Emissions Accounting in the main part.

Stage

Table 7.1-2: Period of the Life Cycle stage of Concrete
Demolition andUsetemporary storage

Reuse

Period(5) Time and geographical references
As described in 3 (1), this methodology aims at CO2 uptake by cement at its life cycle stages where
cement after production and sales is used in buildings and structures for a given use stage, demolished,
and then reused (e.g. subbase material).
There are two approaches for accounting avoided GHG emissions: the flow base approach; and,the stock base approach 1. The former approach is to calculate cumulative amounts of greenhouse gas
emissions avoided by using the assessed goods or services manufactured or sold within a specificassessment period (e.g. for one year), assuming that they are used until the end-of-life (productlifetime). The stock base approach is to calculate amounts of emissions avoided by using (or throughother processes of) all the assessed goods or services, including those from past sales, that are inservice during a specific assessment period. Either shall be selected in this methodology.
The coverage of accounting shall be specified to determine the CO2 uptake by cement, for example,
within the country, outside the country, or both, to meet the purpose of the study.

(6) Baseline
The baseline is an assumption of a case where materials (e.g. timber) which do not absorb CO2 areused in buildings and civil engineering structures.

23

(7) Mechanisms of avoided GHG emissions
Cement consists mainly of four major minerals which are alite (3CaO·SiO2), belite (2CaO·SiO2),
calcium aluminate phase (3CaO·Al2O3) and ferrite phase (4CaO·Al2O3·Fe2O3). When used inconcrete, these minerals react with mixing water (hydration) to produce C-S-H, calcium hydroxide(CH) and calcium aluminate hydrates including ettringite (3CaO·Al2O3·3CaSO4·32H2O) andmonosulfate (3CaO·Al2O3·CaSO4·12H2O). The hydrates in the cement paste of concrete compriseroughly 55 to 65% of C-S-H, 15 to 25% of CH and 10 to 15% of calcium aluminate hydrates including
ettringite and monosulfate. These cement hydrates can be normally present in stable forms inhardened cement or concrete. However, these minerals containing CaO as a chemical constituent form
CaCO3 through carbonation under the presence of water (moisture, etc.) and CO2 which act as reaction
media. The hydrated phases of concrete have a dense and porous structure which allows atmospheric
CO2 to enter through the pores and diffuse inside.
Carbonation is one of the critical deterioration factors for concrete structures, and measures aretaken to control carbonation in the material and mix proportion designs as well as during construction
and other activities. However, cement in concrete structures generally has a long period of use of
more than several ten years. Carbonation occurs and develops to a considerable extent during that
period, which results in absorption of CO2. Concrete after use in structures is demolished and reused.
The demolished concrete is in a massive form and has new surface layers which have previously been
inside the structures. This causes further carbonation and then absorption of CO2.
Table 7.1-3 shows the carbonation processes of cement hydrates. It should be noted that the Degreeof carbonation depends on the diffusion of CO2 into the hardened concrete, rather than the progressof the chemical reaction.
Table 7.1-3: Carbonation Processes of Cement Hydrates*
Cement hydrates
Reaction formulae of carbonation
C-S-H
3CaO·2SiO2·3H2O + 3CO2 → 3CaCO3 + 2SiO2 + 3H2O
Ca(OH)2 + CO2 → CaCO3 + H2OCHEttringite
3CaO·Al2O3·3CaSO4·32H2O + 3CO2
Monosulfate*→ 3CaCO3 + 2Al(OH)3 + 3CaSO4 + 29H2O
3CaO·Al2O3·CaSO4·12H2O + 3CO2
→ 3CaCO3 + 2Al(OH)3 + CaSO4 + 9H2O

Since carbonation is a reaction using water as medium, H2CO3 can be used in place of CO2 in the reaction formula.

24

4.

Accounting methods(1) General information and outline of accounting
CO2 uptake by cement is accounted as a sum of CO2 uptake by cement during its use stage instructure, CO2 uptake by cement during its demolition and temporary storage stage, and CO2 uptake
by cement during its reuse stage. The individual CO2 uptake by cement is accounted by multiplying
CO2 uptake by cement per 1 m3 of carbonated zone of concrete (t/m3) with volume of concrete in the
carbonated zone (m3).

(2) Settings, estimations and assumptions in the accounting method for the common
indicator for the use stage and the demolition and temporary storage stage2-1) Accounting of the CO2 uptake by cement per 1 m3 of carbonated zone of concreteThis protocol uses the following accounting equations 2 recommended by Danish Technology
Institute (DTI).
<Accounting equation>
𝑀𝑀𝐶𝐶𝐶𝐶2𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝑎𝑎 = 𝛾𝛾𝑐𝑐 ×
×
×
1000
100
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶

where,
𝑎𝑎: CO2 uptake by cement per 1 m3 of carbonated region of concrete (t/m3)
𝛾𝛾𝑐𝑐 : Degree of carbonation
𝐶𝐶: unit cement content in concrete (kg/m3)
𝐶𝐶𝐶𝐶𝐶𝐶: CaO content in cement (%)
𝑀𝑀𝐶𝐶𝐶𝐶2 : molar mass of CO2 (= 44.0 g/mol)
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶 : molar mass of CaO (= 56.1 g/mol)

The Degree of carbonation 3 used here is a coefficient to express the ratio of CaO in cementtransforming to CaCO3 due to carbonation. The value shall be properly determined based on reliablereference materials and experimental data. It is also necessary to properly set unit cement content in
concrete and CaO content in cement. Table 7.1-4 shows examples of chemical compositions ofordinary portland cement and portland blast furnace slag cement type B published by Japan Cement
Association.
Table 7.1-4: Examples of Chemical Composition of Cement
Chemical composition (%)
Cement types
SiO2
Al2O3
Fe2O3
CaO
Ordinary portland cement
20 to 23
3.8 to 5.8 2.5 to 3.6
63 to 65
Portland blast furnace slag
24 to 27
7.0 to 9.5 1.6 to 2.5
52 to 58
cement (type B)2-2) Accounting of the volume of concrete in the carbonated zone
Volume of concrete in the carbonated zone during the use stage is calculated by multiplying surface
25

area of a concrete structure or building with carbonation depth. Volume of concrete in the carbonatedzone during the demolition and temporary storage stage is calculated by multiplying volume of
concrete to be reused after demolition with volume of the carbonated zone per unit volume. For the
calculation using the former accounting formula, or for the calculation of volume of the carbonatedzone per unit volume in the latter case, carbonation depth needs to be determined.
This section describes settings in the calculation method for carbonation depth which is a common
indicator for the use stage and the demolition and temporary storage stage. Other indicators for theaccounting of carbonated zone of concrete characteristic to the use stage and the demolition andtemporary storage stage, respectively, are described in (3) Accounting equations below.
Equations available for accounting the carbonation depth from the surface of a concrete structure
or building include the formula presented by Japan Society of Civil Engineers in the Standard
Specifications for Concrete Structures 4, and the formula proposed by Architectural Institute of Japanin the Recommendations for Durability Design and Construction Practice of Reinforced Concrete
Buildings 5 which is based on Kishitani's formula 6 with the impacts of materials, mixing andenvironmental effect standardized based on Shiroyama's 7 and Izumi's 8 Equations (Table 7.1-5).
Since carbonation depth can be influenced by some factors including water-to-cement ratio (W/C) of
concrete and environmental conditions, it is necessary to define proper values and coefficients forthem in the accounting.
Table 7.1-5: Examples of Equation for Evaluationg Carbonation Depth
Proposed by
Equation
Parameters
D: carbonation depth (mm);Japan Society 𝐷𝐷 = (−3.57 + 9.0･𝑊𝑊/(𝐶𝐶 + 𝑘𝑘𝐴𝐴𝑑𝑑 ))･𝛽𝛽𝑒𝑒 ･√𝑡𝑡
of Civil...... [1] k: constant representing theefficiency of the mineral admixture
Engineers

Architectural
Institute ofJapan

𝐷𝐷 = 1.72･𝛼𝛼1 ･𝛼𝛼2 ･𝛼𝛼3 ･𝛽𝛽1 ･𝛽𝛽2 ･𝛽𝛽3 ･√𝑡𝑡...... [2]used (for blast furnace slag: 0.7);
Ad: mineral admixture content;βe: environmental effect coefficient(dry: 1.0)
D: carbonation depth (mm);α1: coefficient representing theeffect of aggregate;
α2: coefficient representing theeffect of types of cement;
α3: coefficient representing theeffect of W/C;
β1: coefficient representing theeffect of ambient temperature;
β2: coefficient representing theeffect of humidity/moisture; β3:CO2(3) Accounting Equations
3-1) CO2 uptake by cement
𝐴𝐴 = 𝐴𝐴𝑠𝑠𝑠𝑠 + 𝐴𝐴𝑑𝑑𝑑𝑑𝑑𝑑 + 𝐴𝐴𝑟𝑟

A: CO2 uptake by cement (t)Asl: CO2 uptake by cement during the use stage (t)Adem: CO2 uptake by cement during the demolition and temporary storage stage (t)26Ar: CO2 uptake by cement during the reuse stage (t)3-2) CO2 uptake by cement during the use stage
𝐴𝐴𝑠𝑠𝑠𝑠 = �(𝑎𝑎𝑖𝑖 ×𝑉𝑉𝑐𝑐−𝑠𝑠𝑠𝑠−𝑖𝑖 )𝑖𝑖

𝐴𝐴𝑠𝑠𝑠𝑠 : CO2 uptake by cement during the use stage (t)𝑎𝑎i: CO2 uptake by cement per 1 m3 of carbonated zone of concrete under specific conditions (t/m3)
𝑉𝑉𝑐𝑐−𝑠𝑠𝑠𝑠−𝑖𝑖 : carbonated volume of concrete under specific conditions (m3)The specific conditions here are, for example, the classifications of structures and buildings
mentioned in a) below.
Hereinafter, ai and Vc-sl-i are generalized and expressed as a and Vc-sl, respectively.
𝑉𝑉𝑐𝑐−𝑠𝑠𝑠𝑠 = 𝐷𝐷×𝐴𝐴𝑒𝑒𝑒𝑒
𝐴𝐴𝑒𝑒𝑒𝑒 =𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑠𝑠𝑠𝑠𝑡𝑡𝑎𝑎𝑎𝑎𝑎𝑎

𝑉𝑉𝑐𝑐−𝑠𝑠𝑠𝑠 : carbonated volume of concrete during the use stage (m3)
𝐷𝐷: carbonation depth (mm)𝐴𝐴𝑒𝑒𝑒𝑒 : equivalent surface area of a structure or building (m2)
𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑠𝑠𝑠𝑠 : amount of concrete during the use stage (m3)𝑡𝑡𝑎𝑎𝑎𝑎𝑎𝑎 : average thickness of members of a structure or building (m)𝑎𝑎 = 𝛾𝛾𝑐𝑐 ×

𝑀𝑀𝐶𝐶𝐶𝐶2𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶××1000
100
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶

𝑎𝑎: CO2 uptake by cement per 1 m3 of carbonated zone of concrete (t/m3)
𝛾𝛾𝑐𝑐 : Degree of carbonation
𝐶𝐶: unit cement content in concrete (kg/m3)
𝐶𝐶𝐶𝐶𝐶𝐶: CaO content in cement (%)
𝑀𝑀𝐶𝐶𝐶𝐶2 : molar mass of CO2 (g/mol) [44.0 g/mol]
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶 : molar mass of CaO (g/mol) [56.1 g/mol]a) Classifications of structures and buildings
Carbonation of concrete occurs as a result of reaction with carbon dioxide present in theatmosphere. It is also known that progress of carbonation is very minor in underground or underwater
structures and buildings where contact with carbon dioxide is limited. In order to consider these
influences, it is necessary to properly classify the environment to which each structure or building is
exposed.
b) Setting of equivalent surface area of structures and buildings
Surface area of each concrete structure or building exposed to atmospheric CO2 shall be properly
defined. For the exposed surface area, equivalent surface area (Aeq) obtained by dividing the amount27

of concrete used in the structure or building in service with average thickness of members can beused.

3-3) CO2 uptake by cement during the demolition and temporary storage stage
Concrete during the demolition stage is present in a form of waste concrete mass to recycled
crushed stone. The state of concrete during demolition period shall be expressed either by appropriate
measurement values or by proper modeling. Recycling rate of the demolished concrete shall beconsidered in accounting of the CO2 uptake.
𝐴𝐴𝑑𝑑𝑑𝑑𝑑𝑑 = �(𝑎𝑎𝑖𝑖 ×𝑉𝑉𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑−𝑖𝑖 )𝑖𝑖

𝐴𝐴𝑑𝑑𝑑𝑑𝑑𝑑 : CO2 uptake by cement during the demolition and temporary storage stage (t)𝑎𝑎i: CO2 uptake by cement per 1 m3 of carbonated zone of concrete under specific conditions (cement
types, etc.) (t/m3)
𝑉𝑉𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑−𝑖𝑖 : carbonated volume of concrete under specific conditions (cement types, etc.) (m3)Hereinafter, ai and Vc-dem-i are generalized and expressed as a and Vc-dem, respectively.

𝑎𝑎 = 𝛾𝛾𝑐𝑐 ×

𝑀𝑀𝐶𝐶𝐶𝐶2𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶××1000
100
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶

𝑎𝑎: CO2 uptake by cement per 1 m3 of carbonated zone of concrete (t/m3)
𝛾𝛾𝑐𝑐 : Degree of carbonation
𝐶𝐶: unit cement content in concrete (kg/m3)
𝐶𝐶𝐶𝐶𝐶𝐶: CaO content in cement (%)
𝑀𝑀𝐶𝐶𝐶𝐶2 : molar mass of CO2 (g/mol) [44.0 g/mol]
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶 : molar mass of CaO (g/mol) [56.1 g/mol]
𝑉𝑉𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑 = 𝑁𝑁𝑁𝑁 × 𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑

𝑉𝑉𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑 : carbonated volume of concrete during the demolition and temporary storage stage (m3)
Nr: volume of the carbonated zone per unit volume (1 m3) of waste concrete mass or recycled crushedstone (m3/m3)
𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑 : volume of concrete during the demolition and temporary storage stage (m3)
𝑁𝑁𝑁𝑁 = � � 𝑁𝑁𝑁𝑁𝑑𝑑𝑑𝑑 ×𝑖𝑖

𝑝𝑝𝑑𝑑𝑑𝑑�100

Nrdi: volume of the carbonated zone per unit volume (1 m3) of waste concrete mass or recycled
crushed stone of particle size di (m3/m3)
pdi: distributional frequency of particle size di in waste concrete mass or recycled crushed stone (%)

28

(𝑑𝑑𝑑𝑑/2) − 𝐷𝐷 3
𝑁𝑁𝑁𝑁𝑑𝑑𝑑𝑑 = 1 − ��(𝑑𝑑𝑑𝑑/2)
where Nrdi = 1 when D > (di/2)
Nrdi: volume of the carbonated zone per unit volume (1 m3) of waste concrete mass or recycled
crushed stone of particle size di (m3/m3)
di: particle size of waste concrete mass or recycled crushed stone (mm)
D: carbonation depth (mm)𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑 =𝑅𝑅𝑐𝑐𝑐𝑐𝑐𝑐
× 𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑠𝑠𝑠𝑠
100

𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑑𝑑𝑑𝑑𝑑𝑑 : volume of concrete during the demolition and temporary storage stage (m3)
NOTE: Use a directly measured value, if available.
Rcon: recycling rate of waste concrete mass (%)
𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑠𝑠𝑠𝑠 : amount of concrete during the use stage (m3)3-4) CO2 uptake by cement during the reuse stage
Concrete during the reuse stage is used mainly as subbase material for road construction. The stateof concrete and environmental conditions shall be properly considered in accounting of the CO2
uptake by concrete during the reuse stage.
𝐴𝐴𝑟𝑟 = �(𝑎𝑎𝑖𝑖 ×𝑉𝑉𝑐𝑐−𝑟𝑟−𝑖𝑖 )𝑖𝑖

𝐴𝐴𝑟𝑟 : CO2 uptake by cement during the reuse stage (t)𝑎𝑎i: CO2 uptake by cement per 1 m3 of carbonated zone of concrete under specific conditions (cement
types, etc.) (t/m3)
𝑉𝑉𝑐𝑐−𝑟𝑟−𝑖𝑖 : carbonated volume of concrete under specific conditions (cement types, etc.) (m3)Hereinafter, ai and Vc-r-i are generalized and expressed as a and Vc-r, respectively.

𝑎𝑎 = 𝛾𝛾𝑐𝑐 ×

𝑀𝑀𝐶𝐶𝐶𝐶2𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶××1000
100
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶

𝑎𝑎: CO2 uptake by cement per 1 m3 of carbonated zone of concrete (t/m3)
𝛾𝛾𝑐𝑐 : Degree of carbonation
𝐶𝐶: unit cement content of concrete (kg/m3)
𝐶𝐶𝐶𝐶𝐶𝐶: CaO content of cement (%)
𝑀𝑀𝐶𝐶𝐶𝐶2 : molar mass of CO2 (g/mol) [44.0 g/mol]
𝑀𝑀𝐶𝐶𝐶𝐶𝐶𝐶 : molar mass of CaO (g/mol) [56.1 g/mol]
𝑉𝑉𝑐𝑐−𝑟𝑟 = 𝑁𝑁𝑁𝑁 × 𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑟𝑟

29𝑉𝑉𝑐𝑐−𝑟𝑟 : carbonated volume of concrete during the reuse stage (m3)
Nr: volume of the carbonated zone per unit volume (1 m3) of subbase material (m3/m3)
𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐−𝑟𝑟 : volume of concrete during the reuse stage (m3)
𝑁𝑁𝑁𝑁 = � � 𝑁𝑁𝑁𝑁𝑑𝑑𝑑𝑑 ×𝑖𝑖

𝑝𝑝𝑑𝑑𝑑𝑑�100

Nrdi: volume of the carbonated zone per unit volume (1 m3) of subbase material of particle size di(m3/m3)
pdi: distributional frequency of particle size di in subbase material (%)(4) Data sources (Sources and rationales for coefficients and others)
Described in (2) and (3) above.

(5) Cut-off criteria
CO2 uptake of a process may be excluded from the accounting if its impact is minor (less than 3%)
to the total CO2 uptake of the target life cycle processes (use, demolition and temporary storage, andreuse).

(6) Allocation
Not applicable in this methodology.

(7) Others
Not applicable in this methodology.

30

References of Annex A
1

Ministry of Economy, Trade and Industry of Japan (2018), Guidelines for Quantifying GHG
emission reductions of goods or services through Global Value Chain, pp. 13.
2
K. O. Kjellsen, M. Guimaraes and Å. Nilsson (2005), The CO2 Balance of Concrete in a Life Cycle
Perspective, Danish Technology Institute.
3
Japan Society of Civil Engineers (2012), Concrete Library 134: Toward CO2 Reduction in Repair,
Demolition and Reuse of Concrete Structures, pp. 92. (in Japanese)
4
Japan Society of Civil Engineers (2018), Standard Specifications for Concrete Structures 2017:
Design, pp. 153-156. (in Japanese)
5
Architectural Institute of Japan (2016), Recommendations for Durability Design and Construction
Practice of Reinforced Concrete Buildings. (in Japanese)
6
Koichi Kishitani (1963), Durability of Reinforced Concrete, Kajima Institute Publishing Co., Ltd.
(in Japanese)
7
Architectural Institute of Japan (1976), Recommendation for Practice of Mix Design of Concrete
and Quality Control in Concrete Work. (in Japanese)
8
Itoshi Izumi (1994), Durability Problems of Concrete Structures and Countermeasures: Carbonation,
Concrete journal, Vol. 32, No. 2, pp. 72-83. (in Japanese)31Annex B ISO 14044 Reference Table
ISO 14044 requirements
4 Methodological framework for life cycle assessment(LCA)
4.1 General requirements

4.2 Goal and scope definition
4.2.1 General
4.2.2 Goal of the study

4.2.3 Scope of the study
4.2.3.1 General

4.2.3.2 Function and functional unit

4.2.3.3 System boundary
4.2.3.3.1

4.2.3.3.2

4.2.3.3.3a) Mass

32

Reference sections in the Protocol―
1.1 Purposes of the Protocol
1.2 Scope of the Protocol
1.4 Developing Process of the Protocol andReferenced Guidelines and Standards
3.2 Application of Life Cycle Approach
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions―
1.1 Purposes of the Protocol
1.2 Scope of the Protocol
1.1 Purposes of the Protocol
3.1 Basic Principles for Avoided GHG
Emissions Accounting
6. Reporting of Avoided GHG Emissions―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
4.1 Principles for developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
2. Terms and Definitions

ISO 14044 requirementsb) Energyc) Environmental significance4.2.3.4 LCIA methodology and types of impacts
4.2.3.5 Types and sources of data

4.2.3.6 Data quality requirements
4.2.3.6.1

4.2.3.6.2
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
4.2.3.6.3

Time-related coverage
Geographical coverage
Technology coverage
Precision
Completeness
RepresentativenessConsistency
Reproducibility
Sources of the data
Uncertainty of the information

Reference sections in the Protocol
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
Related descriptions are given in the following
sections but not exhaustive to cover therequirements on the left.
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions

6. Reporting of Avoided GHG Emissions
Related descriptions are also given in thefollowing section but not exhaustive to cover
the requirements on the left.
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results―
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions4.2.3.7 Comparisons between systems
4.2.3.8 Critical review considerations

4.3 Life cycle inventory analysis (LCI)
4.3.1 General

4.3.2 Collecting data
4.3.2.1

33

ISO 14044 requirements

4.3.2.2

4.3.2.3
4.3.3 Calculating data
4.3.3.1 General

4.3.3.2 Validation of data

4.3.3.3 Relating data to unit process and functional
unit

4.3.3.4 Refining the system boundary

4.3.4 Allocation
4.3.4.1 General

4.3.4.2 Allocation procedurea) Step 1b) Step 2c) Step 3
4.3.4.3 Allocation procedures for reuse andrecycling
4.3.4.3.1
4.3.4.3.2

Reference sections in the Protocol
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
Related descriptions are given in the following
sections but not exhaustive to cover therequirements on the left.
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions――
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
2. Terms and Definitions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
6. Reporting of Avoided GHG Emissions
―
―
―
―
―
―

34

ISO 14044 requirements
4.3.4.3.3
a)b)
4.3.4.3.4
4.4 Life cycle impact assessment (LCIA)
4.4.1 General

a)
b)
c)
4.4.2 Mandatory elements of life cycle impact
assessment (LCIA)
4.4.2.1 General
4.4.2.2 Selection of impact categories, category
indicators and characterization models
4.4.2.2.1
4.4.2.2.2
4.4.2.2.3
a)
b)
c)
d)
e)
f)
g)
4.4.2.2.4
a)b)
4.4.2.3 Assignment of LCI results to the selected
impact categories (classification)a)b)
4.4.2.4 Calculation of category indicator results(characterization)
4.4.2.5 Resulting data after characterization

35

Reference sections in the Protocol
―
―
―
―
―
3.1 Basic Principles for Avoided GHG
Emissions Accounting
3.2 Application of Life Cycle Approach
3.3 Mechanisms of Avoided GHG Emissions
3.4 Trade-off
3.5 Double Counting
3.6 Allocation of Avoided GHG Emissions
3.7 Methodological Framework for Accountingof Avoided GHG Emissions
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―

ISO 14044 requirements
4.4.3 Optional elements of LCIA
4.4.3.1 Generala) Normalizationb) Groupingc) Weightingd) Data quality analysis
4.4.3.2 Normalization
4.4.3.2.1
4.4.3.2.2
4.4.3.3 Grouping
4.4.3.4 Weighting
4.4.3.4.1
4.4.3.4.2
4.4.3.4.3
4.4.4 Additional LCIA data quality analysis
4.4.4.1
4.4.4.2a)b)c)Reference sections in the Protocol
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions―

4.4.5 LCIA intended to be used in comparative
assertions intended to be disclosed to the public
4.5 Life cycle interpretation
4.5.1 General
4.5.1.1――
4.1 Principles for Developing Accounting
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
―
―
―
―
―
―
―
―
―
4.1 Principles for Developing Accounting

4.5.1.2

4.5.2 Identification of significant issues
4.5.2.1
4.5.2.2
4.5.2.3a)b)c)d)
4.5.3 Evaluation
4.5.3.1 General36ISO 14044 requirements

4.5.3.2 Completeness check4.5.3.3 Sensitivity check4.5.3.4 Consistency check
a)
b)
c)
d)
4.5.4 Conclusions, limitations andrecommendations
a)
b)
c)
d)
5 Reporting
5.1 General requirements and considerations
5.1.1
5.1.2
a)
b)
c)
d)
e)
5.1.3
5.2 Additional requirements and guidance for thirdparty reportsa) General aspectsb) Goal of the studyc) Scope of the studyd) Life cycle inventory analysis (LCI)e) Life cycle impact assessment (LCIA),
where applicablef) Life cycle interpretationg) Critical review, where applicable

5.3 Further reporting requirements for comparative

37

Reference sections in the Protocol
Methodologies for Avoided GHG
Emissions
4.2 Accounting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results

6. Reporting of Avoided GHG Emissions――
6. Reporting of Avoided GHG Emissions―
6. Reporting of Avoided GHG Emissions

5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions―

ISO 14044 requirements
assertion intended to be disclosed to the public
5.3.1
a)
b)
c)
d)
e)
f)
g)
h)
i)
5.3.2
a)
b)
c)
d)
e)
6 Critical review
6.1 General

Reference sections in the Protocol
1.1 Purposes of the Protocol
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
―
1.1 Purposes of the Protocol
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
5. Evaluation of the Avoided GHG Emissions
Accounting Methodology and Accounting
Results
6. Reporting of Avoided GHG Emissions

6.2 Critical review by internal or external expert

6.3 Critical review by panel of interested parties

38