Embodied Carbon: Developing a Client Brief - March 2017 - UK Green Building Council
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Embodied Carbon:
Developing a Client Brief
© Derwent London | Brunel Building
March 2017
WO R K S P O N S O R E D BY:
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF iii
Contents
1. Overview 1
2. Introduction 2
2.1 What does this guidance do? 2
2.2 How to use this guide 3
2.3 Why focus the guidance on clients? 4
2.4 What is embodied carbon? 4
2.5 Why is it important? 5
3. Knowing how and what to ask for 10
3.1 Who? 12
3.2 When? 12
3.3 Where? 13
3.4 How? 15
3.5 Why? 16
3.6 What? 17
4. Creating the brief – Putting pen to paper 24
4.1 Context, ambitions and aims 24
4.2 Assessment boundary and reference study period 26
4.3 Assessment scope 26
4.4 Assessment standards and calculation methodology 27
4.5 Data and tools 27
This document is produced for general 4.6 Starting point, iterations and frequency 28
guidance only. How you choose to use 4.7 Presenting the results 29
it is up to you. While the guidance has
been produced in good faith it does 5. Example Brief 30
not constitute advice and UK-GBC and
the authors of this guidance do not 6. What to do with the outputs? 32
represent or warrant that the content
6.1 Benchmarking 32
is suitable for your purposes, accurate,
6.2 Target setting 33
complete or up-to-date. UK-GBC and
6.3 Reducing embodied carbon 33
the authors exclude all liability whether
arising in contract, tort (including
negligence) or otherwise, and will not 7. Glossary 34
be liable to you for any direct, indirect
or consequential loss or damage, 8. References 36
arising in connection with your use of,
or reliance on, the guidance. Supporting Guidance 38
© 2017 UK Green Building Council
© Derwent London Registered charity number 1135153
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Overview 1
1. Overview
With the increasingly successful reduction of operational energy (and thus carbon emissions)
in the built environment, the industry’s next challenge is to reduce the carbon intensity of the
structures themselves (embodied carbon). We know that clients will play a critical role in this
work as what clients ask for, the supply chain works to deliver. UK-GBC also understands that
embodied carbon is an area that many clients are just beginning to address.
This guide is designed for those who need to write effective briefs for commissioning their
first embodied carbon measurements, but who may be at an early stage of embodied carbon
knowledge. It is not a how-to guide for measuring carbon, or which method or tools should
be adopted.
This guide been written by the industry, for the industry. The guidance provides
straightforward information on how to develop a brief and ‘get the job done’. For those
looking for greater depth of knowledge, there is Supporting Guidance with links to further
detailed information.
Embodied Carbon: Developing a Client Brief has been led by a team at the UK-GBC,
supported by a specialist working group. At key points in the development process the guide
has gone to wider UK-GBC member review (primarily with clients). UK-GBC would like to
thank all those who have contributed to this new guide.
“UK-GBC’s vision is of a built environment that is fully decarbonised. This has to include both
embodied and operational carbon. As operational carbon reduces, the relative significance
of embodied carbon increases. So we will continue to advocate for embodied carbon to
become a mainstream issue in building design, construction and maintenance. Indeed, we
will be encouraging our client members and other clients in the industry to create their own
embodied carbon briefs by making effective use of this guidance.
Also, through our work with cities and other local and national authorities, we will be
encouraging the assessment of embodied carbon within the public sector planning and
procurement process.”
Julie Hirigoyen
CEO, UK Green Building Council
© AHMM | Camden Lock Village
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Introduction 2|3
2. Introduction 2.2 How to use this guide
1
Throughout the document there are
signposts which will direct readers to
related sections of the guidance and
2.1 What does this guidance do? further information in the Glossary
The purpose of this The purpose of this guide is to set out clear and Overview and Supporting Guidance.
guide is to set out practical guidance to enable built environment clients
clear and practical to begin requesting embodied carbon measurements. ➤➤ Signpost to relevant
guidance to enable built This includes understanding the outcomes from an section
66 Signpost
environment clients assessment and how to start acting on the results.
to start requesting
embodied carbon
measurement.
This guide has been produced in response to extensive
consultation. Feedback from the UK-GBC membership
indicates a difficulty in knowing exactly where and
how to start the process of measuring embodied
2
Introduction
E
WH RE
Guidance
to Supporting
Readers will benefit from
carbon. Much guidance exists on embodied carbon downloading this document and
WHO
measurement and this document aims to complement reading using Adobe Acrobat.
it with a focus on the contractual demands that clients
3
WHEN
place on their supply chains.
The intended audience is clients who are aware of
the importance of embodied carbon and want to Explains the key
commission an embodied carbon measurement but Knowing how
considerations when writing
do not know where to start. an embodied carbon brief HOW
and what WHAT
to ask for
The guidance explains some of the basics of embodied
carbon, gives an overview of some suggested WHY
approaches, provides example clauses to propel
4
embodied carbon requirements down the supply chain
and gives practical tips on how to use the outcomes
of an assessment. The guidance is appropriate for any Provides example wording for
capital investment intervention in the built environment all the key considerations
explained in Section 3 Creating
such as new build, refurbishment or renewal whether the brief
in buildings, infrastructure or other built assets. The
Supporting Guidance builds on the topics with a
greater level of detail.
5
EMBODIED
CARBON BRIEF
The guidance does not, nor is it intended to, set out
a methodology or standard for embodied carbon Brings together a
measurement, nor does it compare products or give selection of the example
guidance on product level assessments. Rather, it wording from Section 4 Example
helps to set out a usable framework for clients to into one example brief
Brief
begin to develop an approach to embodied carbon
measurement within their organisations. Also, this
6
guidance is not intended to diminish the need to
address the operational carbon of assets in use.
The term ‘brief’ is used to refer
to any document used in the
commissioning of embodied What to do
carbon assessments. with the
outputs
© Derwent London
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Introduction 4|5
2.3 Why focus the guidance on 2.4 What is embodied carbon? 2.5 Why is it important? Embodied Operational
carbon carbon
clients? Embodied carbon is the total greenhouse 22% 78%
2.5.1 High level context
gas (GHG) emissions (often simplified to
Construction projects are initiated by clients.
“carbon”) generated to produce a built asset. At a global level, buildings account for 32% of
Clients are usually the instigators of project’s
This includes emissions caused by extraction, energy use and 30% of energy-based GHG
sustainability agenda. As part of this, clients may
manufacture/processing, transportation and emissions. These emissions will continue to
set out a requirement to measure embodied
assembly of every product and element rise under a business-as-usual scenario.[5] The 2012
carbon. Thus, by increasing awareness and action Total annual built
in an asset. In some cases, (depending on embodied carbon impacts and the impacts of
on embodied carbon at the client level, it will be environment emissions
the boundary of an assessment), it may other built asset types are not accounted for,
introduced to the industry as the supply chain 202MtCO2e
also include the maintenance, replacement, which makes the impact of the whole built
responds to clients’ requests.
deconstruction, disposal and end-of-life environment larger. To play its part in limiting
This guidance has been developed in aspects of the materials and systems that global temperature increase to 2°C, the built
collaboration with UK-GBC members, with a make up the asset. It excludes operational environment sector must reduce its emissions by
particular focus on clients. Members from the emissions of the asset. a total of 84 GtCO2 by 2050.[5]
client side and the supply chain have contributed
Some of the other commonly used definitions As part of the Paris Agreement, member
content and provided feedback.
within the built environment sector include: states will have to transition to net zero-carbon
The following groups were identified as being economies.[6] So far, 91 countries have included
“Carbon emissions associated with energy
‘clients’ and form the primary audience: elements of commitments relating to buildings Embodied Operational
consumption (embodied energy) and chemical
in their Nationally Determined Contributions carbon carbon
• investors (pension funds, private equity processes during the extraction, manufacture, 34% 66%
(NDCs) (these are the national declarations of
funds etc.) transportation, assembly, replacement and
commitment).
deconstruction of construction materials or
• REITs (real estate investment trusts)
products.”[1] In the UK, the Low Carbon Routemap[7] and the 2025
• developer-landlords 2015 Routemap Progress Report highlight that 113MtCO2e
“The carbon dioxide emissions associated with
the sector needs to find a further 39% reduction
• owner occupiers and tenants making a building – as distinct from using it
in carbon emissions[8] from the 1990 baseline in
– are referred to as embodied carbon. More
• local authorities order to meet the Government’s target to reduce
precisely, embodied carbon covers greenhouse
carbon emissions in the built environment by
• infrastructure clients gas (GHG) emissions that arise from the energy
50% by 2025[9]. Longer term, deeper reductions
and industrial processes used in the processing,
will be needed to reach the UK’s Climate Change
manufacture and delivery of the materials,
Act target of 80% reduction by 2050 from a 1990 Embodied Operational
products and components required to construct a
baseline. carbon carbon
building.”[2] 40% 60%
Consideration of embodied carbon within
"Embodied carbon, sometimes referred to as
the built environment at the initial design 2050
capital carbon, refers to the emissions associated 45MtCO2e
and construction stages, especially by the
with the creation of an asset. Capital carbon
construction and property sectors, is necessary
is being adopted in the infrastructure sector
in order to achieve the required GHG reductions
because it accords with the concept of capital
(see Figure 1). The relative significance of
cost"[3]
Embodied carbon is the total embodied carbon is increasing, as both the grid
In terms of the Greenhouse Gas (GHG) Protocol decarbonises and operational emissions decrease Embodied Operational
greenhouse gas (GHG) emissions for emissions accounting, the embodied carbon due to increased efficiency (see Figure 1).
generated to produce a built asset. of built assets is included within Scope 3 Domestic Domestic
This includes emissions caused by emissions.[4]
extraction, manufacture/processing, Non-domestic Non-domestic
transportation and assembly of every Infrastructure Infrastructure
product and element in the asset.
Figure 1 Increasing significance of embodied
carbon (in 80% emissions reduction scenario)[10]
© Walsh | St John Bosco College
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Introduction 6|7
Embodied carbon has been recognised in infrastructure 2.5.2 Why is it important to a client Commercial and Operational Additionally, industry agreements and schemes
with regulation in specific sectors. For example, in organisation? are increasingly referring to embodied carbon
The economic case for considering embodied carbon
the rail industry, the High Level Output Specification as it demonstrates an organisation’s improved
There are now a variety of reasons, beyond the has been outlined in other industry research. The
(HLOS) requires consideration of traction and understanding of carbon in built assets. For example:
environmental, motivating client organisations findings include:
no-traction carbon emissions from railway activities.
to measure their embodied carbon impact. The • Clients signing up to Science Based Targets take
Similarly, Ofwat[11] required all water companies to • Relatively low cost when compared to many
embodied carbon impact at an asset level is more a progressive approach to the measurement and
produce a capital and operational carbon footprint operational carbon saving solutions;
significant than has been previously thought. reduction of all carbon emissions[14]; and
of their proposed 2010-2015 asset investment and
Recent figures show that over a 30-year period, • Encourages lean design and drives resource
management programme.[12] • Companies opting to sign up to the RE100 are
embodied emissions account for more than 50% efficiency;
bringing embodied carbon emissions into stark
At an organisational level, industry standards such as of the total carbon emitted for some building
• Unlocks innovation, provides competitive contrast against annual operating emissions.
PAS 2080:2016 Carbon management in infrastructure types. Consequently, addressing embodied carbon
advantage and export potential;
are encouraging all companies to begin effectively is a critical part of reducing a client’s overall carbon Additionally, some planning authorities are beginning
managing their ‘carbon footprints’, with a strong impact. See (Figure 2). • Gives further insight into GHG risks and to acknowledge embodied carbon.
emphasis on embodied carbon. opportunities;
The aim of this guidance is to help all built • Can be a helpful tool for clients to compare assets,
environment clients to start effectively measuring dependent on a common assessment framework,
embodied carbon. demonstrating embodied carbon improvement
over time; and
• Can assist in achieving credits in some building
assessment sustainability rating schemes.
Industry agreements and schemes
are increasingly referring to embodied
carbon as it demonstrates an
Supermarket Office Semi-detached house Warehouse organisation’s improved understanding
of carbon in built assets.
Product
Figure 2 Relative impact of the consequent life cycle stages
Construction on the overall carbon footprint for different types of
Operational water and energy buildings, calculated over 30 years (energy results have been
based on Building Regulations).[13] All but “Operational water
Maintenance, repairs and energy” relate to embodied carbon
End of life
© Westgate Alliance | Westgate Oxford Alliance
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Introduction 8|9
Reputational Environmental
Organisations are seeking to better understand and The environmental reasons for addressing carbon
manage “what matters most” to their stakeholders.[15] are well documented. Some of the most compelling
An initial embodied carbon assessment can be reasons include:
commissioned using a high level approach. As clients
• Embodied carbon can form a key part of any
carry out more projects, they can build on their
corporate climate change strategy;
embodied carbon knowledge and ask for more
information to a greater level of detail. Similarly, • Addressing embodied carbon offers an attractive,
investor rating and measurement indices are starting to one-time opportunity to make a significant saving
include assessment of embodied carbon. For example: in a shorter period of time, whereas operational
carbon savings unfold over a longer period of
• The Dow Jones Sustainability Index (DJSI) now
time;[18]
includes a section about the life cycle assessment
of building materials; • Consideration of embodied carbon at design
stage can facilitate greater resource efficiency.
• The FTSE4Good Index asks questions on lifecycle
studies and related carbon emissions reductions;
• The CDP includes voluntary reporting of Scope 3
emissions;[16]
• The GRESB survey has a significant volume
of questions on new construction and major
renovations.[17]
Reporting on Scope 1 and 2 GHG emissions has
become more widespread in the built environment
in the past few years. A few companies have begun
to explore Scope 3 emissions measurement at an
organisational level, such as their employee travel. Embodied carbon forms an aspect
Beyond this, only a small minority have begun to of many ESG (environmental,
measure Scope 3 emissions at an asset level. By social and governance) analysts’
measuring and reporting embodied carbon, built research reports, which are
environment clients can take demonstrable action on used to judge the quality of a
Scope 3 emissions. company/investment and its
ability to manage its sustainability
responsibilities.
© Walsh | Bankside © Land Securities | Nova Victoria
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 10 | 11
3. Knowing how and Decide where the main
interaction points are for
what to ask for Decide when the
the project(s)
embodied carbon WHERE
measurement process will Decide who is responsible
This guidance provides a structure for clients to begin building their start, how many iterations for each stage of the
embodied carbon knowledge and move towards developing a brief are required and their embodied carbon
for their first embodied carbon assessment. frequency. measurement process
An initial embodied carbon assessment can be commissioned using
a high level approach. For example, an assessment of the high WHEN WHO
intensity embodied carbon elements[19] e.g. the structural frame. As
clients carry out more projects, they can build on their embodied
carbon knowledge and ask for more information to a greater level of
detail in each assessment e.g. the fixtures and fittings.
Clients can communicate their embodied carbon assessment
requirements more effectively by: EMBODIED
• understanding the key considerations of an embodied carbon CARBON BRIEF
brief;
• being aware of the variables within the assessment and how
they impact the calculation;
• understanding what decisions could be taken and the factors
that influence those decisions. HOW WHAT
Figure 3 represents the key considerations of an embodied carbon
brief. Each key consideration has variables within it which can impact
on the final embodied carbon calculation.
It should be noted that there is no “starting point” for this process. By
exploring these key considerations simultaneously, clients will build WHY
their knowledge base in order to write their first embodied carbon
brief. As such, the following sections can be read in any order. Decide how to incorporate Understand what the
embodied carbon through embodied carbon brief
existing in-house should contain and what
documents. decisions are needed for
each element.
Recognise the drivers for
the organisation to start to
measure embodied carbon
and what the objectives of
the assessment are.
Figure 3 The key considerations of an embodied carbon brief
© Matt Chisnall
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 12 | 13
3.1 Who? 3.2 When? 3.3 Where?
WHO WHEN E
WH RE
Decide who is responsible Decide when the Decide where the main
for each stage of the embodied carbon interaction points are for
embodied carbon measurement process the project(s)
measurement process will start, how many
iterations are required 3.3.1 Where are the
3.1.1 Who should and their frequency decision points?
engage in the embodied carbon process?
Clients can assess where to engage in the project
3.2.1 Starting point, iterations and frequency
Clients can own the embodied carbon process to according to where there are critical decision points
ensure that it remains a priority throughout the project. The starting point for an assessment on a project rather than specific actors, roles or responsibilities. As
This can be achieved by assigning responsibility to one affects the level of impact that can be had on the project teams move from one construction phase to
person to deliver the embodied carbon assessment, embodied carbon outcome. the next, more construction details are “locked in”
thereby ensuring a continued focus and awareness through the decisions made. These are the critical
Embodied carbon reduction is best tackled by
across the whole project team. This is especially decision points which also “lock in” embodied carbon.
measuring as early as possible during design so that
important when interacting with the design and Clients can review where these decision points are in
reduction opportunities can be highlighted and acted
contractor teams who will be responding to the brief advance, ensure that any decisions are taken according
upon. Clients can outline the intent to measure and
in terms of how decisions impact the measurement to the embodied carbon brief, and then capture data
reduce embodied carbon before conceptual design
and reduction of embodied carbon. In these cases, as required.
begins. This should ensure that the project team is
it may be beneficial to use a common framework
conscious of this intent during the design phase. These critical decision points also affect a client’s
which designates responsibilities to each party, such as
commercial team. The design and material choices will
PAS 2080.[20]
➤➤ Section 6.3 Reducing embodied carbon affect layout and product specifications which, in turn,
affect aesthetics, comfort, durability and saleability.
The greatest value can be derived when embodied
Table 1 identifies major embodied carbon decisions
carbon assessments are treated as an iterative
that can be taken at particular stages during the
exercise rather than a one-off activity. Clients who
construction process.
commission an early assessment at the conceptual
design stage may find it valuable to repeat the study
3.3.2 The impact of different project
in order to compare the original design with both the
procurement routes
progressed design and the final as-built product.[21]
This comparison will reveal how the embodied carbon There are many different procurement processes that
impact has changed between the project stages. are used to commission a project. Different procurement
routes will use differing approaches to producing and
➤➤ Section 4.6 Starting point, iterations and issuing tender information and communicating client
frequency requirements. Therefore, it is important to discuss the
best route with the project management team to
ensure that the embodied carbon requirements are
understood and clearly set out.
In addition to setting out clear requirements, a clear
line of responsibility should also be established to
ensure the assessment work is completed to the
level of detail specified. In many circumstances
this means clients (either themselves or via their
project representatives) will instruct a third party
consultant to undertake an embodied carbon
assessment. Sometimes in design and build contracts
this responsibility will be passed directly to the
contractor, who in turn may employ a consultant to
undertake the embodied carbon assessment.
© Westgate Alliance | Westgate Oxford Alliance © Westgate Alliance | Westgate Oxford Alliance
EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 14 | 15
Table 1 Embodied carbon and work stages
3.4 How? HOW
Decide how to incorporate
Project Embodied Carbon – actions and processes Scale of opportunity embodied carbon through
stages to influence existing in-house documents
embodied carbon Consider how embodied carbon
objectives and requirements are to
Brief Creation of embodied carbon “brief”, setting out boundary, be communicated to the design
measurement points, information/data points, presentation and construction teams. The requirements can be
format etc. embedded in a wide range of documents such as:
This also needs to be included as part of the tender and • scopes of service;
procurement process, which are essential parts in undertaking
and reducing embodied carbon. Some structural decisions are • Employer’s Requirements;
made very early on in the process which can affect embodied • specifications;
carbon.
• requests for proposal; and
Design At this point, the structural frame can be examined more • construction contracts.
easily, which is where a large proportion of embodied
carbon emissions are locked in, e.g. the amount of cement The method used to communicate requirements may
replacement materials (CRMs) in the foundations. As the also depend on when measurement processes start
design reaches final sign off, ability to influence decreases. and any iterations required.
Build Clients can influence a limited range of materials choices. ➤➤ Section 3.2 When?
Handover There are no further opportunities to influence the embodied
carbon of the build. However, clients will be able to influence,
guide and recommend for the fit-out. An embodied carbon
assessment at this stage can be valuable as a benchmark
against future projects, assuming there has been consideration
at earlier stages of how to gather the requisite data.
Operation It is not appropriate to do an embodied carbon assessment of
the original build at this stage as reductions cannot take place.
Significant future opportunities arise however when looking
at fit out, replacement cycles of plant and materials or when
a major renovation is due. However, at this stage a high level
assessment of the original build materials could be undertaken
which may help to understand the impacts of the assets.
© Walsh | BanksideEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 16 | 17
3.5 Why? Preparing a statement of relevant long term ambitions 3.6 What? Some reporting or assessment schemes determine
WHY and short term objectives will help make the supply WHAT what and how embodied carbon is assessed.
Recognise the drivers for Understand what the
66 Supporting
chain aware of the environmental and carbon specific
the organisation to start to embodied carbon brief
aims of the client organisation. This can help to: Guidance: 5. Whole built
measure embodied carbon should contain and what
asset level assessment methodologies
and what the objectives of the • align reporting needs; decisions are needed for
requirements for embodied carbon
assessment are each element.
• aid with carbon transparency; and
This section gives specific instructions on what is
Context and ambitions • improve data efficiencies further down the line. 3.6.1 What are the objectives for an embodied
included in the embodied carbon calculation, which
carbon assessment?
Embodied carbon is just one aspect of the many The statement could also be specific to property includes multiple variables. In order to fully understand
sustainability concerns of a client. Explaining the full portfolio objectives such as developing a common the embodied carbon figures, it is worth considering It is useful to establish what is to be achieved from
context of the organisation’s approach to sustainability assessment framework in order to compare projects how changing a variable of the calculation will impact knowing the embodied carbon impact of a built asset.
allows the supply chain to respond to the embodied and demonstrate carbon performance over time. the final result. Consider the following:
carbon measurement request appropriately.
The calculation and the variables should not change, • “I simply want an appreciation of embodied
➤➤ Section 4.1 Context, ambitions and aims for
This context could include: in order to ensure consistency of measurement within carbon quantities in my asset.”
the example wording
a portfolio. This is preferable to enable meaningful
• identifying any current company carbon or GHG • “I want to know the embodied carbon emissions
comparisons.
66 Supporting
requirements of my asset at every stage of the design and
—— compulsory reporting standards e.g. mandatory delivery process.”
Guidance: 6. Setting up
GHG reporting
meaningful comparisons • “I want to see reductions in the embodied carbon
—— voluntary reporting standards e.g. CDP
footprint of my asset.”
• any environmental management system However, calculation variables may change, such as
The objective will inform the choice of embodied
requirements that could be impacted by, or if a more sophisticated assessment is performed.
carbon assessment boundary.
have an impact on, the embodied carbon data Consequently, it will not be possible to compare
gathering process. measurements with previous assessments. Clients are advised to use their first measurement as an
opportunity to drive down embodied carbon though
design and construction choices.
© Matt Chisnall | TurnmillEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 18 | 19
3.6.2 Boundaries Consequently, the principal boundaries to consider are: Boundaries and Procurement, Example A: The company will be selling the asset on completion
Ownership and Management and therefore the company will not have information on the asset’s
The boundary sets the scene for assessment and Cradle-to-completed construction: use after the sale. An appropriate boundary for this situation could be
further defines the emissions to be included or This will best reflect scenario 1 above (references When considering the boundary, cradle-to-completed construction.
excluded according to the life cycle of the built asset. BS 15978 modules A1 to A5).* it is also worthwhile to consider
how the asset is to be procured, Example B: The company may sell the asset on completion but is still
The brief includes the most appropriate boundary for Cradle-to-grave:
constructed, and managed, along weighing up options to occupy or manage the asset for a minimum
an assessment. Put simply, understanding where to This will best reflect scenario 2 above (references
with whether any ownership will term of 5-10 years. Selecting cradle-to-construction with an additional,
draw the boundary is essentially deciding which of BS 15978 modules A1-A5, B1-B5 and C1-C4 and,
be retained post-handover. This is alternative calculation which includes the maintenance, repair and
these scenarios is a better fit: optionally, D.)
66 Supporting
useful because the perspectives replacement cycles for the period under consideration.
of a developer-landlord differ
Guidance: 2. What is the technical
Scenario 1: from speculative developers or an Example C: The company will retain the asset on completion and
basis for identifying “life cycle stages”?
owner-occupier. The assessment occupy and manage the asset for a minimum of 25 years. In this case
“I would like to know the carbon critical hotspots results can help decision-making,
and how much carbon has been generated in There are other considerations that may be taken the company may wish to conduct a cradle-to-grave assessment as it
especially for long-term issues, such will include all the operational impacts they are likely to incur over the
delivering my asset, as it stands when I get the when setting the boundary. Clients may opt to
as future climate change scenarios. operational period.
keys” look at issues relating to the boundary, such as
Decisions on material choices will
the procurement route, future ownership and
differ based on the embodied Example D: The company will occupy a tenanted area of a shell and
management as appropriate to the maturity of their
carbon impact, which depends on core developed asset and will be responsible for the fit-out, as well as
Scenario 2: embodied carbon knowledge.
the reference study period of the future management and maintenance, for the period of approximately
“I would like to know how much carbon has been Clients may wish to use a boundary aligned with future assessment. 10 years. An appropriate boundary is cradle-to-grave for the fit-out
generated in delivering my asset, and I also want tenure arrangements. This boundary could be called materials, which can be used to inform the embodied carbon impact of
The reference study period is
to know how much will be generated when I “cradle-to-transfer of ownership” and could be used in the maintenance, repair and replacement cycles.
the duration of time used in the
operate, maintain and dispose of my asset in the situations where clients wish to build, operate, maintain
assessment. For example, in a
future.” and then sell. It would cover BS 15978 modules A1-A5, Example E: The company is planning to retain and operate the asset
cradle-to-grave assessment, the
B1-B5. for 10 years at which point they are required to demolish the asset. In
reference study period(s) could be
20 years, 60 years or 100 years i.e. this case, they may be interested in a cradle-to-grave assessment to
the period of time for which the minimize future carbon liabilities and identify opportunities to recover
*
BS EN 15978:2011 Sustainability of construction works. Assessment of environmental client wants information. value from the materials/carbon already invested in the building.
performance of buildings. Calculation method.
Consider the following examples
Best practice for whole-life carbon assessment is to consider multiple
of how scenarios, boundaries and
reference study periods and present results as a series of scenarios.
reference study periods interact:
A practical starting point is a commitment to a cradle-to-completed
construction boundary. This provides a well-balanced picture of the
embodied carbon footprint of the asset in question as it stands in reality,
regardless of the ownership structure and future tenure.
Over time, it would be advisable for clients, particularly those involved in
ongoing operation and maintenance, to be more involved in cradle-to-grave
issues. Using a wider boundary offers the opportunity for a more in-depth
understanding of:
• the impact of decisions at the capital expenditure stage which affect
embodied carbon on the operational carbon in the use stage; and
• the embodied carbon impact of maintenance and replacement cycles.
Understanding both of these issues can help clients with design decisions
and materials choices.
➤➤ Section 4.2 Assessment boundary and reference study period
for the example wording
© Carillion | Manchester Metropolitan HospitalEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 20 | 21
throughout the design stages to make the final 3.6.3 Assessment scope 3.6.4 Assessment standards and calculation
Assumptions and Certainty assessment as accurate as possible. methodology
Two issues to be aware of when undertaking an
The assessment scope sets out what is included and
Certainty also decreases the further into the future excluded from the embodied carbon measurement. For embodied carbon assessments of built assets, the
embodied carbon calculation are: life cycle of the asset that the assessment covers. use of the standard BS 15978 is becoming an industry
• the level of certainty of the data available at the When looking over the whole asset life, the less The assessment scope may be defined as:
norm.[23] This standard sets out a basic methodology
time of assessment; and certain the data becomes given that the future • a project level, e.g. new construction or fit-out; for life cycle assessment (LCA) in buildings by splitting
management and operational regime are unknown the life cycle into modules. These modules are used to
• the standardised assumptions that are made • an asset level;
and cannot always be predicted accurately. In structure the embodied carbon calculation.
about the life cycle of assets e.g. maintenance
66 Supporting
scenarios where the maintenance regime and
regimes. • an activity level, e.g. solely the structure of a single
replacement cycle is not known, assumptions
asset or across a portfolio. Guidance: 2. What is the technical
Embodied carbon assessments are estimates unless have to be made in order to give a reasonable
basis for identifying “life cycle stages”?
the calculation is performed on an as-built asset embodied carbon estimate. An awareness that The scope will also include a description of the physical
with a complete embodied carbon data set and only these assumptions have been used is valuable parameters of an asset e.g. gross floor area (GFA).
in understanding the final result of an embodied For civil engineering works there is a pending standard,
measuring up to the point of handover. Consequently, This is necessary to enable the results to be suitably
carbon assessment. prEN 15643-5:2016 Sustainability of Construction
the level of uncertainty in an assessment depends on presented. It is good practice to include a description
Works – Sustainability Assessment of Buildings and
where the project is in the life cycle and how far into Where possible, stating the known, or assumed, of the use of an asset.
Civil Engineering Works – Part 5: Framework for the
the future the calculation is taken. operational regimes and end of life scenarios of the Assessment of Sustainability Performance of Civil
If the starting point is at the conceptual design asset is recommended. Where there are unknowns, ➤➤ Section 4.7 Presenting the results
Engineering Works.[24]
stage of a project, the assessment will be based on clients can engage with the assessors in order to
assumptions and best guesses as to what materials determine the most appropriate assumptions. This It should be noted that the scope is distinct from the For the infrastructure sector, there is also PAS 2080
the final asset may contain. As the design progresses, will prevent assessors having to make arbitrary boundary of the assessment. The boundary defines the which is a carbon management framework.
certainty around the materials in the asset increases assumptions. Transparency of the assumptions will life cycle stages to be included. The scope defines the
Finally, RICS has produced a detailed embodied
and therefore, the embodied carbon assessment assist with future comparability across a client’s particular emissions that are included or excluded in
carbon calculation methodology which builds on the
becomes more certain. It is recommended that portfolio. every life cycle stage of the boundary.
BS 15978 assessment standard.[25] Currently, assessors
provision is made in the brief to repeat the assessment Scope considerations might include: will typically choose either to use this methodology
or develop their own approach. Conforming to one
• Is there a physical or geographical boundary?
or more of the above standards and methodologies
e.g. is the curtilage of the assessment site clearly
can provide a more robust process for, and a greater
defined?
degree of confidence in, any calculations of embodied
• Is there a project boundary with an associated carbon figures.
66 Supporting
cost plan?
Guidance: 3.1 Presenting LCA
• What level of detail is needed? e.g. Can the
results in a structured format
80:20 rule be applied in order to identify the high
intensity/high volume embodied carbon areas?
➤➤ Section 4.4 Assessment standards and
• What activities are included? e.g. Will the
calculation methodology for the example
embodied emissions of the materials and the
scope wording
construction site emissions of every single activity
on the project be included?
• Define any exclusions from the assessment. e.g.
demolition emissions.
➤➤ Section 4.3 Assessment scope for the example
scope wording
Figure 4 Conceptual diagram showing ability to influence carbon reduction across the different work stages
of infrastructure delivery[22]EMBODIED CARBON: DEVELOPING A CLIENT BRIEF Knowing how and what to ask for 22 | 23
3.6.5 Data and tools 3.6.6 Presenting the figures The data should be presented in line with the
requirements set out in the scope which should include
Embodied carbon calculations need conversion factors The final part of the brief specifies how the embodied
physical parameters of an asset e.g. tCO2e/m2 GFA. The
to convert quantities of materials into embodied carbon assessment should be presented. It is useful
results of the assessment can also be normalised in
carbon figures. For this, there are a number of data to have the information broken down in a variety of
terms of the functionality of an asset e.g. kgCO2e/FTE.
sources available. The assessment standards or ways in order to make easier comparisons between
These intensity metrics should be in line with a client’s
calculation methodologies do not endorse particular assets. Comparisons between assets which have used
normal practice.
66 Supporting Guidance: 8. Targets
embodied carbon data sources (with the exception of exactly the same boundary and the same calculation
environmental product declarations (EPDs)). methodology are possible.
66 Supporting
If multiple assessments are being conducted, defining
Guidance: 6. Setting up
which dataset and tool are used in the embodied Best practice is also to request that the timing of
meaningful comparisons
carbon calculations will improve the consistency of the emissions is clearly stated e.g. where maintenance and
results. repair cycles are considered.
66 Supporting Guidance: 4.1 Data and 4.3 Tools
The results of an assessment might be broken down
by: As well as presenting the figures, the assessment
should detail all assumptions that have been made,
• Structural building elements, e.g. substructure,
e.g. maintenance regimes, and be reported within
superstructure etc.;
Data Quality the relevant section of the output, e.g. the assumed
• Components, e.g. walls, floors, cladding etc.; maintenance regime is reported within the boundary
The quality of data in embodied carbon assessments
section.
varies according to its source. There are data quality • Carbon sources, e.g. transport, materials, site
standards, which clients can specify to ensure a robust activities etc.;
➤➤ Section 4.7 Presenting the results for the
approach to embodied carbon calculations is adopted.
66 Supporting Guidance: 4.1 Data
• Work package; and example wording
• Location.
➤➤ Section 6. What to do with the outputs?
Presenting the data in a variety of ways highlights
Clients can also specify if the assessment should use
issues such as:
verifiable data (and can request proof for audit, if
required). It is recommended to ask an assessor to • where the carbon hotspots are;
outline which standards can be complied with and to
• what kind of control the client has over them;
verify all data sources used in the calculations.
• how the asset will be affected by proposed
➤➤ Section 4.5 Data and tools for the example mitigation measures; and
wording
• who should be involved in the mitigation
measures decisions.
© Derwent London | Turnmill
© Derwent London | TurnmillEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Creating the brief – Putting pen to paper 24 | 25
4. Creating the brief – Example wording:
Putting pen to paper Example 1:
has committed to achieving lower embodied
carbon emissions in line with 2050 targets and it is aiming to achieve
a carbon neutral status by 2030.
This section is designed to help with writing the embodied carbon brief Example 2:
and provides example wording. Below are suggested sections to include is undergoing its first steps into embodied
which cover the major elements of an embodied carbon commissioning carbon assessment and would like to understand the embodied
document. carbon impact of its assets. There is also an overarching company
objective to explore our Scope 3 emissions as part of our CDP
Each section includes:
reporting process. Ongoing embodied carbon assessment forms part
• An explanation as to why the section should be included; of our ISO 14001 certification.
• Example wording. Example 3:
has an interest in delivering low impact assets
In the example wording, where content is highlighted in < > brackets,
and is therefore interested in measuring the embodied carbon
individual company information should be inserted.
impact. Sustainability is a core value of our business and we seek to
make all of our new assets carbon neutral by 2025. We will achieve
this through operational efficiency and through reducing embodied
impacts.
4.1 Context, ambitions and aims Example 4:
The brief starts by informing the assessor of the need for the embodied would like to understand the relationship
carbon assessment. This could include: between cost, efficiency and low embodied carbon buildings.
• the company specific context;
• relevant sustainability objectives; Optional wording 1:
• relevant overall carbon aims; The embodied carbon assessment must also be aligned with, and
deliver compatible data for, our existing carbon processes including:
• previous experience and/or studies in embodied carbon
measurement and reduction; and • ISO 14064-1 Greenhouse gases – Part 1: Specification with
guidance at the organization level for quantification and
• identifying any drivers and objectives as to why this data is required.
reporting of greenhouse gas emissions and removals.
• ISO 14064-2 Greenhouse gases – Part 2: Specification with
guidance at the project level for quantification, monitoring and
reporting of greenhouse gas emission reductions or removal
enhancements.
• The Greenhouse Gas (GHG) Protocol Scope 3 Standard;
• PAS 2080:2016 Carbon management in infrastructure.
Additional wording:
© Matt Chisnall | Turnmill
• Regular embodied carbon reporting of our assets which
informs our selection of materials, products and suppliers
throughout the project and on future projects.*
* This wording can be used independently or in addition to the preceding points. © Matt ChisnallEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Creating the brief – Putting pen to paper 26 | 27
4.2 Assessment boundary and reference 4.3 Assessment scope 4.4 Assessment standards and calculation 4.5 Data and tools
study period This section defines the scope of the assessment, methodology The next step is to request that the data sources are
which may be at a project, asset or activity level, e.g. disclosed in the report. Clients may outline which
The brief sets the most relevant boundary for an The brief then sets out any standards or calculation
new construction, a refurbishment or strip out/fit out. embodied carbon data, databases and calculation tools
organisation’s interests and future planning. The methodologies to which the assessment should
If helpful, further detail can be given around which are preferred. This section could also stipulate the data
example wording refers to the two most often used conform. The calculation methodology is a choice
project activities are included and excluded from the quality control rules.
boundary conditions for clients as well as using the between the RICS Methodology or the assessor’s
calculation.
potential “cradle-to-transfer of ownership” boundary. own approach. Calculations which do not use these
standards or methodologies should request the
assessor to justify this choice and explain the approach
used.
Example wording: Example wording: Example wording: Example wording:
Example 1: Asset Function: Example 1: The following industry data and/or databases are
The boundary to be used is cradle-to-completed The asset being assessed will be an . Assessment of environmental performance of • Proprietary data and databases
Example 2:
buildings
The boundary to be used is cradle-to-grave, Example 1: • The University of Bath ICE database
comprising BS 15978 modules A1-A5 and B1 The scope is limited to an assessment of Example 2:
The following calculation tools are preferred:
to B5 over a 30-year reference study period. the structural components (sub-structure, The methodology for calculation will be based
Module D benefits are to be excluded. superstructure and façade) of . Embodied Carbon. Any deviations from this must
Example 3: • Any proprietary tools may also be considered
be justified and agreed.
The boundary to be used is cradle-to-grave, Example 2: if they are demonstrated to create materially
comprising BS 15978 modules A1 to C4 The scope is limited to the fit-out of including floor and wall finishes as well The methodology for calculation will conform Differences in calculations should be justified.
transport, waste processing and disposal, over as major interior items. to BS 15978:2011 and will also use the RICS
Data quality:
a 60-year reference study period. Module D Methodology to calculate embodied carbon.
Example 3:
benefits are to be included. Data gathering shall conform to ISO 14025:2010 • The assessment shall include a general
The scope is limited to an assessment of
Environmental labels and declarations. Type commentary on data quality for the project.
Example 4: including earthworks,
III environmental declarations. Principles and
The boundary to be used is “cradle-to-transfer demolition, all construction materials, construction • Scoring of data quality for each data source is
procedures. An audit trail shall be presented.
of ownership”, comprising BS 15978 modules operations and maintenance. also recommended.*
A1 to C4 (excluding B6 and B7) over a 20-year
Example 4:
reference study period. * This wording can be used independently or in addition to the preceding points.
The scope of the assessment will include direct
Example 5: and indirect GHG emissions associated with
The boundary to be used is “cradle-to-transfer of .
ownership”, comprising BS 15978 modules A1 to
Example 5:
C4 (excluding B6 and B7) over 10-year, 20-year
The scope of the assessment will exclude
and 60-year reference study periods.
emissions from design stage (paper and office
consumption) and worker commuting activities.
© Derwent LondonEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Creating the brief – Putting pen to paper 28 | 29
4.6 Starting point, iterations and frequency 4.7 Presenting the results most impact. Alternatively, the list of suggestions
could be based on parameters such as the materials
The brief states the stages at which the assessment The brief states the way in which the final assessment
used in the elements and components, or reductions
will take place i.e. the starting point and details any is presented. This will include all assumptions that have
achievable in each project stage after the assessment.
further iterations. If this embodied carbon assessment been made.
is the first, it can be used as a baseline for future The example wording uses generic terminology for
A comprehensive breakdown of the results will enable
comparisons. It should be noted that the starting point breakdowns of building elements and components.
the client to better understand where the embodied
has an impact on the opportunities for embodied Official RICS terminology can be used to avoid
carbon impact lies. This depth of understanding can be
carbon reductions. confusion and different interpretations. Alternatively,
used to inform decisions made at later stages in the
in-house terminology can be used for the breakdown
project and on future projects.
detail.
Clients can request a list of reduction strategy
suggestions e.g. the top five which would have the
Example wording: Example wording:
Example 1: Example 3: Assumptions: Additionally, the breakdown shall include:
Three iterations of the assessment are required. The starting point will be at briefing stage and
All assumptions must be clearly stated. .
selection may affect the final outcome. Number and appropriate.
3. Handover stage.
timing of iterations are to be agreed in conjunctionEMBODIED CARBON: DEVELOPING A CLIENT BRIEF Example Brief 30 | 31
5. Example Brief
The example brief below assembles a selection of
the example wording from Section 4 into a single
document.
EMBODIED CARBON BRIEF 2
EMBODIED CARBON BRIEF
The brief starts by informing Clients may outline which
the assessor of the need for the Data and tools embodied carbon data, databases
embodied carbon assessment. This The following industry data and/or databases are preferred for embodied carbon calculations: and calculation tools are preferred
could include: Context and company objectives • Environmental Product Declarations (EPDs) and request that the data sources
has an interest in delivering low impact assets and is therefore interested in • Proprietary data and database are disclosed. This section could
• the company specific context; measuring the embodied carbon impact. Sustainability is a core value of our business and we seek to
make all of our new assets carbon neutral by 2025. We will achieve this through operational efficiency
• GaBi database also stipulate the data quality
• relevant sustainability and through reducing embodied impacts. The following calculation tools are acceptable: control rules.
The embodied carbon assessment must also be aligned with, and deliver compatible data for, our
objectives; existing carbon processes including:
• Impact-compliant tools
• Any proprietary tools may also be considered if they are demonstrated to create the same outputs
• relevant overall carbon aims; • ISO 14064-2 “Greenhouse gases – Part 2: Specification with guidance at the project level for
quantification, monitoring and reporting of greenhouse gas emission reductions or removal
The assessment shall include a general commentary on data quality for the project. Scoring of data
enhancements”.
quality for each data source is recommended. This section states the stage at
• previous experience and/or • Regular embodied carbon reporting of our assets which informs our selection of materials, which the assessment will take
studies in embodied carbon products and suppliers throughout the project and on future projects. Starting point, iterations and frequency
place i.e. the starting point, and
measurement and reduction; Boundary
The starting point will be at briefing stage and there will be periodic iterations of the assessment.
wishes to frequently monitor the embodied carbon and understand how details any further iterations. If this
and The assessment will report on three boundaries, as defined using BS 15978:2011 “Sustainability of
material selection may affect the final outcome. Number and timing of iterations are to be agreed in
conjunction with the embodied carbon assessor. embodied carbon assessment is the
• identifying drivers and
construction works. Assessment of environmental performance of buildings. Calculation method”.
Where the first assessment is to be before product selection, initial calculations should be based on first, it can be used as a baseline
1. Cradle-to-completed construction, comprising BS 15978 modules A1-A5. RICS component benchmarks or use estimated quantities and the GaBi database. This generic data
objectives for the data. should be substituted for detailed product data as the design progresses and subsequent iterations of for future comparisons. It should be
2. “Cradle-to-transfer of ownership”, comprising BS 15978 modules A1 to C4 (excluding B6 and B7)
over 10-year, 20-year and 60-year reference study periods.
the assessment are prepared. noted that the starting point has
3. Cradle-to-grave, comprising BS 15978 modules A1 to C4 (i.e. including demolition, transport, waste
Presenting the results
an impact on the opportunities for
processing and disposal) over a 60-year reference study period.
embodied carbon reductions.
All assumptions must be clearly stated.
The brief sets the most relevant Scope of the embodied carbon assessment The results of the assessment shall be presented in the following way:
boundary for the organisation’s Asset function: The asset being assessed will be a mixed use development incorporating residential and
retail tenants.
• Total kgCO2e per building element as defined as: substructure, superstructure, cladding, exterior
works, services, and any other major element.
interests and future planning. The assessment shall include the structural components (sub-structure, superstructure and façade). The • Total kgCO2e per material as defined as: foundation concrete, structural steel, etc.
This section states the way in which the final
fit-out, floor and wall finishes, as well as major interior items, are included.
• Total kgCO2e per major building component as defined as: frame, internal and external walls, floors, assessment is presented. This will include
The assessment will exclude emissions from design stage (paper and office consumption) and worker
commuting activities.
roof, windows and doors, etc. all assumptions that have been made. A
This section defines the scope of
• Total kgCO2e per work package.
comprehensive breakdown of the results will
Assessment standards and calculation methodology • The results shall include intensity metrics, as defined by: kgCO2e per m2 and tCO2e per £100k cost,
enable the client to better understand where
the assessment, which may be at kgCO2e per residential occupant.
a project, asset or activity level e.g.
The methodology for calculation will conform to BS 15978:2011 and will also use the RICS
“Methodology to calculate embodied carbon”. Data gathering shall conform to ISO 14025:2010
• Each breakdown should be expressed as a proportion (%) of the total embodied carbon footprint. the embodied carbon impact lies. This depth
new construction, refurbishment or “Environmental labels and declarations. Type III environmental declarations. Principles and procedures”. The assessment shall provide the top five suggestions for reducing embodied carbon impact (including of understanding can be used to inform
An audit trail shall be presented. the reasoning) to inform the next stage of the project.
strip out/fit out. If helpful, further decisions made at later stages in the project
detail can be given around which and on future projects.
project activities are included and Clients can request a list of reduction strategy
excluded from the calculation. suggestions, e.g. the top five which would
This section sets out any standards or calculation methodologies have the most impact. Alternatively, the list of
to which the assessment should conform. The calculation suggestions could be based on parameters
methodology is a choice between the RICS Methodology or the such as the materials used in the elements
assessor’s own approach. Calculations which do not use these and components, or reductions achievable in
standards or methodologies should request the assessor to each project stage after the assessment.
justify this choice and explain the approach used.
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