WHOLE-LIFE CARBON
FOOTPRINT MEASUREMENT
AND OFFICES
MARCH 2012
ABOUT THE BCO
IMAGES
The British Council for Offices’ (BCO) mission is to
research, develop and communicate best practice
in all aspects of the office sector. It delivers this by
providing a forum for the discussion and debate of
relevant issues.
COVER
Tree rings
Copyright © Zenmontage | Dreamstime.com
ABOUT THE AUTHORS
Prof. Angus McIntosh, Economic and Sustainable
Property Consultant, Real Estate Forecasting Ltd,
and Oxford Brookes University (formerly Director and
Chairman of UK Research, Jones Lang LaSalle,
and Partner & Head of Research, King Sturge LLP)
Gareth Roberts FRSA, MRICS, MSC REEF, BSC ARCH,
Research Director, Sturgis Carbon Profiling LLP, and
Research PhD Student, London School of Economics
ACKNOWLEDGEMENTS
The BCO would like to thank the members of the
Steering Group for giving their time to this project.
They are:
PAGE 11
Severn Trent Regional Office, Shelton
Architect: Glenn Howells Architects
Courtesy of Glenn Howells Architects
PAGE 23
Victoria Station, London
Copyright © Lucian Milasan | Dreamstime.com
PAGE 14
Piccadilly Gate, Manchester
Architect: Archial Architects
Courtesy of Ocon Construction
PAGE 26
Demolition site
Copyright © Peter Elvidge | Dreamstime.com
PAGES 35 and 47
Mills Bakery, Royal William Yard, Plymouth
Architect: Gillespie Yunnie Architects
Courtesy of Urban Splash
John Connaughton, Davis Langdon (Chairman)
Miles Keeping, GVA
David Clark, Cundall
Stephen Runicles, BDP
Daniel Winder, Sheppard Robson
Jenny MacDonnell, British Council for Offices.
COPYRIGHT © BRITISH COUNCIL FOR OFFICES 2012
All rights reserved by British Council for Offices. No part of this publication may be reproduced, stored or transmitted in any form or by
any means without prior written permission from the British Council for Offices. The BCO warrants that reasonable skill and care has
been used in preparing this report. Notwithstanding this warranty the BCO shall not be under liability for any loss of profit, business,
revenues or any special indirect or consequential damage of any nature whatsoever or loss of anticipated saving or for any increased
costs sustained by the client or his or her servants or agents arising in any way whether directly or indirectly as a result of reliance on
this publication or of any error or defect in this publication. The BCO makes no warranty, either express or implied, as to the accuracy
of any data used by the BCO in preparing this report nor as to any projections contained in this report which are necessarily of any
subjective nature and subject to uncertainty and which constitute only the BCO’s opinion as to likely future trends or events based on
information known to the BCO at the date of this publication. The BCO shall not in any circumstances be under any liability whatsoever
to any other person for any loss or damage arising in any way as a result of reliance on this publication.
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
CONTENTS
Foreword
4
Preface
5
Executive summary
6
Background
The issues
Evolution of whole-life reporting
Carbon emission sources evaluated
Whole-life carbon footprints from different
building types
8
8
9
12
Methodology and issues
The CEN/TC 350 family of standards
Product stage
Construction stage
In-use stage
Commuting
End-of-life stage
After-life stage (not included)
14
14
16
18
20
23
24
26
Examples
Overview
Building-type details
27
27
27
13
Discussion
Effect of workplace practices on whole-life
carbon performance
The implications of productivity differences
for whole-life carbon emissions
30
Conclusions
34
Key findings
Outcomes: some suggested answers from
this research
Future research
29
29
34
35
36
References
37
Glossary
39
Appendix 1: The carbon footprint of a building
40
Appendix 2: Travelling to work
41
Appendix 3: Report worksheets
46
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WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
FOREWORD
The property industry is finally getting to grips with
operational carbon, the part created by people using
the building, but this is only half the story, the other
half being the carbon used to create the materials, the
products and the systems that make up that building.
The term ‘whole-life carbon’ captures these two key
components. In April 2011, the BCO’s Environmental
Sustainability Group produced an Environmental Briefing
Note on this same subject, and now we have expanded
our work to provide greater detail for our members.
Whole-life carbon is becoming increasingly important
as the UK continues to use legislation as a means of
reducing carbon emissions as part of its response to
climate change.
As legislation and design standards concentrate on
reducing the operational emissions, the scales begin
to tip, and greater importance is placed on those
emissions embodied within the production of the building.
Environmental legislation continues to be a key factor
in office design and development. Through a better
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© BCO 2012
understanding of whole-life carbon, companies can
begin to form a picture of emissions arising from each
stage of the building process, from the production of
the construction materials through to the deconstruction
process. With the current focus on refurbishment in a
difficult economy, this report is very timely, as we can now
consider fully the environmental benefits of rethinking
the use of older buildings. In carbon terms, it makes
more sense to re-use old buildings than to demolish
them and start again.
I would like to thank all the members of the Steering
Group who contributed their time to ensuring that this
report reaches its current high standards. Also, thank
you to the research team for addressing this important
subject on behalf of the BCO. I am delighted to commend
this report to you.
Paul Edwards (Hammerson)
Chairman, BCO Environmental Sustainability Group
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
PREFACE
On 9 February 2011, the British Council for Offices’
Environment and Sustainability Group appointed
Angus McIntosh of Real Estate Forecasting and
Oxford Brookes University (formerly of King Sturge
LLP and Jones Lang LaSalle) and Gareth Roberts of
Sturgis Carbon Profiling LLP to produce a report
entitled Whole-Life Carbon Footprint Measurement
and Offices. The origins of this report arose from
earlier work undertaken by the British Council for
Offices’ Environment and Sustainability Group.1
This report sets out to provide a simple but robust
methodology for measuring the whole-life carbon
footprint of an office. More specifically, the research
undertaken to produce this report asks:
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How should we measure the whole-life carbon
emissions that office buildings generate?
What insights can we gain by integrating a measure
of productivity for different offices?
How do we demystify whole-life carbon reporting for
all those involved with construction and property?
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How do you compare an unproductive office with
a low carbon footprint with a highly productive office
with a large carbon footprint? Are they both as bad,
or as good, as each other?
How do productivity differences across the UK affect
the whole-life reporting of emissions from buildings,
and does this create a regional bias that unfairly
gives some buildings a competitive advantage
while penalising others?
How do we avoid unintended consequences, such as
demolishing existing buildings because they fail to meet
the requirements of environmental rating schemes
that do not take impacts embodied in materials etc.
into account?
What methods exist to measure economic output?
How does rent relate to the annual total office cost,
and is rent a good proxy for productivity?
The terms used in this report are defined in the Glossary
(see page 39), and References can be found on page 37.
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WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
EXECUTIVE SUMMARY
Why is the whole-life carbon footprint important? The
key contribution that whole-life carbon reporting makes
is its ability to take account of all sources of carbon
emissions associated with buildings, and not just those
that arise as buildings are used. In April 2011, the BCO
produced an Environmental Briefing Note entitled
Whole-Life Carbon as an introduction to this increasingly
important topic. The present report is the significantly
more substantial follow-up. It delves into and demystifies
the whole area of carbon emissions and office buildings.
It looks at the measurement of emissions in relation to
different office-building types, the relationship between
emissions and productivity, and differences in emissions
across the UK.
The five categories are:
This report is intended to be useful to all those who
own, build, let and/or occupy commercial real estate.
Whole-life carbon will increasingly become part of our
lives as the UK responds to climate change through
evolving legislation.
A typical example of a whole-life carbon footprint for a
building is shown in Figure 1. The output may be
expressed as carbon dioxide equivalents (kg CO2e)
per person or kg CO2e per square metre.
The report explains what a whole-life carbon footprint
is, according to the new CEN/TC 350 calculation
methodology,2 which is part of a new set of European
standards for the sustainability of construction. Using
this standard, the report clarifies how a whole-life
carbon footprint is calculated, and explains which
sources of data may be used. The significance of
CEN/TC 350 lies in the recommendations contained
in Low Carbon Construction, a report prepared by the
Innovation and Growth Team (IGT) of the Department
for Business Innovation & Skills,3 which calls for the
UK government to introduce mandatory whole-life
carbon reporting for all buildings as soon as possible.
In this report the measurement of whole-life carbon
emissions is examined through the four main categories
given in the CEN/TC 350 calculation methodology; in
addition, the report introduces an additional source –
commuting. The inclusion of commuting when assessing
office buildings is argued to be necessary due to the
impact that the location of a building has on carbon
emissions related to staff traveling to work.
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materials production (carbon emissions arising from
the production processes used to make building
materials)
construction process (carbon emissions arising from
site works etc.)
occupation of the building (carbon emissions arising
through heating, lighting, cooling and power usage)
transport (including commuting, but not business
travel)
end-of-life carbon (de-construction only, not
including any potential recycling values).
The whole-life carbon values in Figure 1 are taken from
the examples presented later in this report for a range
of different office types. The examples are based on a
60-year reporting period (which is questioned later),
and take into account grid decarbonisation. Changing
5500–8500 kg CO2e/m2
80,000–120,000 kg CO2e/person
Commuting
End of life
In use
Construction
Product manufacture
Figure 1 An indicative whole life carbon split for a
new build office in 2010
Source: Sturgis Carbon Profiling (2010)
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
the basis on which the values are calculated would
give rise to a much wider range of figures than shown
in Figure 1.
Product manufacture – typically 15–20% The carbon
emissions generated at this stage arise from extracting
the raw materials from the ground, their transport to a
point of manufacture, and the primary energy used (and
the associated carbon impacts that arise) in transforming
the raw materials into construction products.
Construction – typically 1–5% These carbon impacts
arise from transporting the construction products to
site, and their subsequent processing and assembly
into the building.
In-use – typically 50–75% This covers a wide range
of sources, from the carbon emissions associated with
the operation of the building, including the heating,
lighting, cooling, small power demands, maintenance
and repair over a 60-year assessment period.
Transport in use – typically 20–40% These are the
emissions generated by staff commuting to and from
a particular building. Access to the local transport
infrastructure around a building can have a significant
impact on the overall commuting carbon emissions
arising from a given building. This report does not
include other business travel.
End of life – typically 1–5% These are the emissions
associated with the eventual deconstruction and
disposal of an existing building at the end of its life.
This value takes into account the on-site activities of
deconstruction contractors involved in the demolition
etc., but does not account for any future carbon benefit
associated with the re-use or recycling of materials
into new products.
To illustrate the methodology given in CEN/TC 350,
this report provides examples of whole-life carbon
calculations for four different office types found across
the UK:
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Central London air-conditioned offices
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CBD Regional City air-conditioned offices
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CBD Regional City non-air-conditioned offices
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Out-of-Town Business Park air-conditioned offices.
In addition, the report examines some of the implications
of workplace practices on whole-life carbon figures, and
how the productivity of buildings in different locations
poses challenges and opportunities for legislators
introducing carbon-reduction legislation.
One of the initial observations is that the way in which
space is used has a significant effect on the carbon
performance of an asset. As the primary function of
an office is as a workplace for people, it is contended
that measuring carbon impacts on a per person basis
is more meaningful than basing measurements on
floor area.
A second point of discussion is that introducing effective
legislation and incentives to reduce carbon emissions
from commercial offices is complex, given the productivity
of different office types. An incentive that works well
in one submarket to create behavioural change may,
quite possibly, be an undue burden in another.
The reader is reminded that this is a scoping report,
outlining how a whole-life carbon footprint for an office
building is calculated, and highlighting some of the
associated issues and implications for commercial
office buildings. The report recommends that further
research and analysis is needed.
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WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
BACKGROUND
THE ISSUES
One of the major challenges when analysing the wholelife carbon of a built asset is the wide variety of emission
sources that affect performance. In addition, there are
complexities of ownership between landlords, tenants
and end users, who all have different, and unaligned,
interests in the fabric and energy use. Figure 2 shows
some of these broader issues and their impact on the
whole-life carbon performance of a building. In reality,
the relationship between each of the issues may be
even more complex than shown in the figure.
Although this report aims primarily to explain what a
whole-life carbon footprint is, the authors are mindful
of this wider context, and do not wish to paint an overly
simple picture by not acknowledging these broader
issues. In the Discussion section later in this report,
some of these issues are examined and suggestions
are made for further research.
Economic output
and
investment return
Intensity of use
and
adaptability
Embodied carbon
Whole-life
carbon
footprint
Transport emissions
Building management
systems
Occupier behaviour
© BCO 2012
The new CEN standard will become increasingly
important in the context of the EU Energy Performance
of Buildings Directive,5 which, when it is updated, will
have to take into account the new CEN standards as
the default measure for rating the carbon performance
Carbon in use
and
renewables
Fabric performance
and
weather
8
This report defines the whole-life carbon footprint of a
building according to CEN/TC 350, the new set of
European standards that is designed to harmonise all the
methods of appraising the sustainability of construction
used in different member states. The standard that
establishes the calculation methodology for carbon is due
to come out by the end of 2011; initially, the use of this
methodology will be on a voluntary basis. The content of
this standard (and the measurement scopes outlined) are
employed in this report. In many respects, the standard
builds on the current PAS 2050 framework for goods
and services,4 but with a building-specific orientation.
Figure 2 Issues surrounding a
whole-life carbon footprint
Source: Sturgis Carbon Profiling,
King Sturge (JLL), BCO, London,
2011.
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
of buildings. In addition, the Department for Business
Innovation and Skills report Low Carbon Construction
calls for the UK government (in Recommendation 2.1)
to introduce mandatory whole-life carbon reporting for
all public building projects as soon as possible.
So why is the whole-life carbon footprint so important?
The key contribution that whole-life carbon reporting
makes is its ability to take into account all sources of
emissions associated with a building, not just those
that arise when the building is in use.
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Is it better from a carbon perspective to knock down
an existing building and replace it with an efficient
new building, given that the construction of the new
building will give rise to additional carbon emissions
over and above those derived from refurbishing the
existing building?
How do we balance the carbon emissions generated
by making materials against the carbon savings
that can be achieved through improved building
performance over the life of a building (e.g. insulation
and increased thermal mass)?
What are the explicit carbon costs and benefits over
the life of a building, and how do these change
over time?
Whole-life carbon measurement and reporting helps
make it possible to choose the correct low-carbon
management strategies and helps avoid unintended
consequences in the future. This, in turn, helps
identify the carbon liabilities that a building owner
may face in the future, as well as at present.
Whole-life carbon measurement also helps us to
compare the benefits of sourcing materials locally
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with using materials that are produced further afield
but which may be more carbon efficient.
Whole-life reporting describes the relationship
between the replacement cycles of materials and
components and the ongoing impacts generated
through maintenance and repair.
Whole-life carbon measurement can also be used as
a basis for examining the carbon intensities of different
building types with respect to economic productivity,
which may be of relevance to policy-makers when
designing fiscal decarbonisation incentives to be
applied to buildings.
Unlike the evaluation of whole-life carbon, most other
benchmarks and standards are focused only on carbon
in use and the incentives available to encourage
the generation of ‘green’ energy. Carbon emissions
relating to embodied carbon (i.e. construction and
materials) and transport are not normally measured.
The present report does not consider issues relating
to ‘green’ energy or heat generation, the use and
efficiency of equipment, or other sustainability issues
such as biodiversity or ecology. It focuses solely on
the measurement concepts, and the implications of
measuring carbon emissions and the use of office
buildings over their lifetime.
These interrelated issues have been amusingly discussed
by Tim Harford (who writes as The Undercover Economist
in the Financial Times) in his recent book Adapt, in a
chapter entitled ‘Climate change or changing the rules
for success’.6
EVOLUTION OF WHOLE-LIFE REPORTING
2011 marks 50 years of environmental whole-life
assessment,7 which may beg the question of why it
has taken so long for the construction industry to become
more aware of this as a method of building appraisal.
This is especially perplexing given that buildings are
responsible for 33% of global carbon emissions, once
all whole-life carbon sources have been considered.8
A simple response to this question is that the effects
of the 1970s fuel embargoes focused occupiers’ (and
more importantly legislators’) attention on the energy
that buildings use, and by default the associated carbon
emissions whilst in use, rather than considering energy
in the round through whole-life reporting. This dissociation
may have also been helped by the manner in which the
construction industry has historically operated, in that
the parties that build and carry the cost of construction
are invariably not the same as those that use, operate or
own buildings throughout their life. Many of the low-carbon
buildings that have been built are owner-occupied,
rather than leased.
Alternative procurement procedures that have been
developed over the last 10 years, such as the Private
© BCO 2012
9
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Finance Initiative (which obliges a group of partners
to take design, construction and finance, as well as
facilities management, responsibilities for a built asset
under a fixed-price contract) have served to renew the
interest in whole-life measurement techniques, which
help us understand how impacts compare over different
time periods.
As a consequence, today we have a construction
sector that in some areas has achieved significant
improvements in carbon performance, thanks mostly to
regulation. However, in other areas, which are currently
not regulated, many potential carbon savings are only
just beginning to be explored.
An example of the above is the current government
policy for reducing the carbon emissions associated
with electricity usage in buildings by subsidising solar
photovoltaic (PV) panels. These yield comparatively
small carbon savings. However, the use of cement
replacements, such as flyash or ground granulated blast
furnace slag (GGBS –a cement replacement that has
much lower carbon-emission impacts than conventional
ordinary Portland cement), often incurs little or no
additional costs, and has the potential to generate
significant carbon savings during the construction phase.
electricity that are regulated, which is why PV panels
are used in many new buildings today, and cement
replacements are frequently not considered because
they do not count towards regulatory targets.
This situation is further complicated by the fact that
many measures introduced for the purpose of reducing
‘in-use’ carbon emissions also give rise to additional
non-regulated carbon emissions from the manufacture
of the materials in the first instance. The PassivHaus
Standard9 is a classic example of this.
Whole-life carbon footprinting allows the analysis of all
these questions by cataloguing all the carbon costs and
benefits that accrue from a building throughout its life. It
can be seen from Figure 3 that significant carbon savings
have been achieved in terms of the regulated emissions
(i.e. those arising from the heating, lighting and cooling
of a typical building), while there has been less progress
in terms of the whole-life perspective (the total emissions).
These ranges shown in Figure 3 are indicative of a
trend, and are discussed later in this report.
The reasons for these trends are varied and complex,
but there are a number of key factors, such as:
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Of the two methods of achieving carbon savings
detailed above, it is the emissions associated with
The greater the effort that is made to reduce
operational emissions, the greater the requirement
to use carbon-intensive construction materials
12,000
Commuting
In use
End of life
Construction
Product manufacture
Whole-life carbon (kg CO2e/m2)
10,000
8,000
6,000
Regulated
‘in-use’
emissions
4,000
2,000
0
1990
2000
Year of construction
10
© BCO 2012
2010
Figure 3 How carbon
impacts from buildings have
changed over time
Source: Sturgis Carbon
Profiling LLP (2011)
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
and technologies, thereby sometimes increasing
the non-regulated footprint.
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Behavioural aspects, such as people’s consumption
of energy as a consequence of improved building
thermal performance; i.e. now that it is cheaper to
achieve a given level of environmental comfort,
occupiers may decide to opt for a higher level of
environmental comfort. This is particularly prevalent
in residential buildings, where people commonly
heat their homes to higher temperatures the better
the building fabric performs.
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Other time-dependent relationships, such as the
overall effects of wealth in society and technological
progress, also give rise to an upward trend. As
businesses and occupants become more prosperous,
they demand accommodation that provides higher
levels of internal comfort, e.g. all-year air-conditioning.
Conversely, the effects of the recession in the last
couple of years have seen some businesses targeting
energy efficiency to improve their competitiveness,
and as a consequence reducing their emissions at
the same time.
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There are other changes in the property market that
have forced office-construction typologies to change.
For instance, increases in land values in some city
centre sites have resulted in more deep-plan offices
being built, with a greater dependence on mechanical
ventilation and cooling to maintain a comfortable
internal environment.
The effect of having a partially regulated construction
sector (with regard to carbon emissions) is that there
are two different MAC curves* for the construction
industry: those for regulated emissions, which bunch
together at a relatively much higher level, and those
for non-regulated emissions, which are substantially
lower. Reconciling these two sets of cost curves
should, therefore, be seen as the key priority in
delivering increased carbon reductions at a minimal
cost increase to the construction industry. (The earlier
discussion comparing solar PV panels with GGBS
illustrates this issue.)
Gaining an understanding of these relationships,
by employing techniques such as whole-life carbon
footprinting, will help achieve this goal, and will become
more important as the UK moves towards 2019 and
achieving its Kyoto Protocol Commitments, as set out
in The UK Low Carbon Transition Plan10 and the UK
Climate Change Act 2008.11
Specifically, the UK National Audit Office12 has identified
the above issues with respect to the government’s own
estates, where establishing methods to meet environmental
targets at minimal cost has to become a priority.
*A MAC (marginal abatement cost) curve describes the incremental cost of achieving emission reductions at a given total
level of required emissions reductions. Typically, at low levels of total emissions reduction, incremental costs will be low, as
there are plenty of ‘easy wins’. However, as higher total levels of emissions reductions are desired, the incremental costs
will increase, as more complex measures need to be adopted.
© BCO 2012
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WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
CARBON EMISSION SOURCES EVALUATED
The whole-life carbon footprint of a building includes
all the emission sources associated with constructing
and using a building over its life and that cause damage
to the atmosphere, as established in the CEN/TC 350
calculation methodology referred to earlier.
The unit of measurement is the carbon dioxide
equivalent (kg CO2e). All the greenhouse gases
generated (including carbon dioxide, methane, nitrous
oxide etc.) are expressed in these units. For each
unit of carbon dioxide produced, one unit of CO2e
is registered. For methane, 21 units of CO2e are
registered, as methane causes 21 times* more
damage to the atmosphere than one unit of carbon
dioxide.9 For each greenhouse gas, a factor is applied
to give the equivalent to carbon dioxide. Further details
can be found on the Defra website.13
Quantifying carbon dioxide emissions from buildings
involves identifying the whole range of emission
sources from a building, including those arising from
the heating, lighting and cooling of the building, and all
those that emerge during its life (often taken as 60 years).
Some of the sources of emissions from a building are
identified in Figure 4.
Full details of all the sources examined are set out in
the section Methodology and Issues (see page 14).
Embodied carbon sources
Operational carbon sources
Cooling
Heating
Roof
Computers
Plant
Internal fit-out
Lighting
Façades
Small power
Structure
External works
Figure 4 Sources of carbon dioxide emissions from buildings
Source: Sturgis Carbon Profiling LLP (2011)
*This figure is known as the ‘global warming potential’ (GWP) of a gas. Its size depends on both the gas itself and the time
horizon over which comparisons are being made against carbon dioxide. Taking a short horizon of 20 years, methane has a
GWP of 72, but over 500 years this figure drops to 7. The GWP values updated yearly by Defra13 should be used when
carrying out whole-life carbon reporting.
12
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WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
WHOLE-LIFE CARBON FOOTPRINTS FROM DIFFERENT BUILDING TYPES
A point to note about the whole-life carbon footprint of
different building types is that the relative proportion
of carbon impacts in each assessment phase varies
greatly, as do their typical absolute amounts. In Figure 5
the total area of each pie chart reflects the absolute
quantity of whole-life carbon emissions, and each
segment reflects the contribution of each assessment
phase to this total. As can be seen, for offices the
emissions due to the manufacture of products is
typically around 10–30% of the total. For homes this
percentage is much lower, in the region of 5–15%,
while for retail storage it may be as high as 60–70%.
These differences highlight the limitations of only
regulating in-use emissions. While for most building
types the in-use emissions are significant, for some
Offices
Warehouses
buildings, such as warehouses, the majority of the
emissions are unregulated (warehouses have much
lower overall and in-use carbon footprints per unit
area). Regulations are currently being set to reduce
the in-use emissions from a building to zero (for homes
this may be as soon as 2016), but this will not affect
the majority of warehouse buildings, the majority of
emissions from which arise from unregulated sources.
As the whole-life carbon impacts of each building type
are quite different in size and distribution, care should
be taken when making comparisons. To this end there
is an urgent need for a set of reliable whole-life carbon
benchmarks for different building types so that building
owners and occupiers can make meaningful comparisons.
Supermarkets
Houses
Embodied
carbon
Operational
carbon
End of life
Construction
Commuting (not considered)
In use
Product manufacture
Area of the circle denotes the absolute quantity of emissions generated
Figure 5 Percentage of embodied carbon per unit area dor different building types
Source: Sturgis Carbon Profiling LLP (2011)
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WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
METHODOLOGY AND ISSUES
THE CEN/TC 350 FAMILY OF STANDARDS
The whole-life carbon scopes described here are based
on the methodology contained in the new CEN/TC 350
family of standards, which has been designed to
harmonise the assessment of the sustainability of
construction works across Europe. The organisation
responsible for this is Technical Committee 350 (TC 350)
of the European Committee for Standardization (CEN).14
In addition to the methodology for whole-life carbon, this
committee is also establishing calculation methodologies
for evaluating the economic and social effects generated
by buildings and construction products.
When the CEN/TC 350 standards are published they will
initially have two purposes: first, to provide a technical
basis on which European countries can compare the
carbon performance of buildings with knowledge of what
is being represented; and, second, to provide a metric
for future European legislation on regulating the carbon
emissions of buildings. To these ends, when the current
Energy Performance of Buildings Directive (EPBD)
14
© BCO 2012
2010 is updated or any other new European Directive
is introduced which requires carbon measurement in
buildings, the new CEN/TC 350 standard described
here can be used as the default.
In the UK, legislation may move faster, as the first
recommendation of the 2010 IGT report, Low Carbon
Construction, to the UK government states:
Recommendation 2.1: That as soon as a
sufficiently rigorous assessment system is in
place, the Treasury should introduce into the
Green Book a requirement to conduct a whole
life (embodied + operational) carbon appraisal.15
In many respects, the new CEN/TC 350 calculation
methodology builds on earlier standards such as
PAS 2050.16 However, as it is designed specifically for
buildings, it clarifies many of the grey areas. Crucially,
it clears up some of the reporting confusions by stating
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Construction stage
Product stage
A1
A2
A3
A4
A5
Raw material
supply
Transport
raw material
Manufacturing
Transport
Site
works
In-use stage
B1
B2
B3
B4
B5
B6
B7
In use
Maintenance
Repair
Replacement
Refurbishment
Operational
energy use
Operational
water use
End-of-life stage
C1
C2
C3
C4
Deconstruction
Transport
Waste
processing
Disposal
Commuting
Bus
Train
Car
By foot
Figure 6 The scope of the new CEN/TC 350 carbon calculation methodology
Source: Briefing on resource efficiency implications of CEN/TC 350, CRWP (2010)
that, at the product stage, recycling benefits should be
included, but at the end-of-life stage any future recycling
benefits should not be included, and can only be reported
separately from the main whole-life figures produced.
This paves the way for more consistent comparisons
between construction materials.
Figure 6 indicates the four main categories identified in
the CEN/TC 350 calculation methodology of emission
sources that accrue over the life of a building (product
manufacture, construction stage, in-use and end-of-life
– excluding any future recycling benefits or potential).
These, in turn, are split into further subcategories
relating to the individual emission sources in each
category (e.g. transport emissions or emissions from
construction-site based activities).
While there are primarily only four stages in the
whole-life carbon footprinting of buildings, as identified
by CEN/TC 350, the present report identifies a fifth
additional category – commuting emissions – as these
are also largely determined by building characteristics
and location. Figure 1 (see page 6) shows that the
emissions associated with commuting can be
significant for office buildings – they can account for
up to 35% of a building’s whole-life carbon footprint –
and this is why in this report, which has a particular
focus on office buildings, it is recommended that these
emissions are included in the calculation.
In the following pages each of the four main
assessment stages identified in the CEN/TC 350
calculation methodology is described, with commuting
included as a separate emission source. After the
description of each assessment stage, the sources
of data used in the assessment are identified, and
the basic method of calculating the carbon emissions
illustrated generically. All data sources are identified
by the Construction Emissions Community of Practice
(CECoP),* which established a consensus on which
data should be used when conducting a whole-life
carbon analysis for the IGT report Low Carbon
Construction for the UK government.
*CECoP is formed of a cross-section of different companies and organisations that are involved in reporting and measuring
construction emissions.
© BCO 2012
15
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
PRODUCT STAGE
The scope of the product-stage emissions includes:
to arrive at an accurate picture, the amount of material,
its density and its ability to perform a specific task need to
be understood. As an example, a comparison between
two cladding alternatives used in recent projects is shown
in Figure 8. In this example, the all-aluminium system
shown on the left-hand side would generate more carbon
emissions than the mixed aluminium and steel system,
although each system is capable of achieving the
same level of cladding performance.
Product stage
A1
A2
A3
Raw material
supply
Transport
raw material
Manufacturing
This stage refers to the emissions that are due to the
making of the products that form buildings. They are
the carbon emissions that arise from extracting the
raw materials from the ground, the transport of raw
materials to a point of manufacture, and transforming
the raw materials into construction products that can
be used on site. Figure 7 gives average product-stage
emissions for some different materials.
It is only possible to make comparisons between
the carbon emissions of two materials when the total
emissions are known for each material performing the
same task. The example shown in Figure 8 suggests
that combining a steel frame with aluminium may
reduce the embodied carbon, as compared with an
aluminium-only frame.
It is worth noting that, although some of the materials
in Figure 7 can be used as substitutes for one another,
comparisons should not be made on a kg CO2e/kg basis.
Aluminium and steel are good examples of this, where,
Two further points of caution that should be heeded
when aiming to specify materials with the lowest
carbon emissions. First, average emissions quoted in
databases (e.g. the Inventory of Carbon & Energy
10
Product construction emissions (kg CO2e/kg)
9
8
7
6
5
4
3
2
1
0
Aluminium
Brick
Carpet
(per m2)
Insulation
Paint
Glass
Copper
Figure 7 Typical carbon dioxide emissions arising from basic construction materials
Source: ICE, University of Bath, BSRIA (2011)
16
© BCO 2012
Steel
Plastic
Concrete
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Aluminium framing
Aluminium panels and windows
Steel framing
Aluminium panels and windows
Total embodied carbon
782 t CO2e
Total embodied carbon
582 t CO2e
Figure 8 A comparison between a steel and an aluminium cladding system
Source: Sturgis Carbon Profiling (2011)
Secondly, different types of products are more or less
durable, depending on the manner in which they
deteriorate. If a material requires frequent replacement,
over the lifetime of a building, the combined impacts of
the material may be much greater than the impact of
a more durable product having a higher initial impact.
Here designers and cost consultants need to be
mindful of other market driving forces (i.e. functional
obsolescence and changes in aesthetic values) that
may impact on the longevity of the material or its
16
Product construction emissions (kg CO2e/kg)
(ICE) database17) are not actual carbon emissions. It
may be worth trying to gain as much information as
possible on the components of a product’s footprint
when making a specification choice. Although, on
average, aluminium has a higher carbon footprint than
steel, it can in fact take a range of values. This is
because the primary determinant of the carbon
footprint of aluminium is the source of the electricity
used in its manufacture, which in some instances may
be hydroelectric power, which has very low carbon
impacts. The process for manufacturing steel, however,
requires large amounts of coke in the blast furnace,
and there are few viable alternative processes. This
gives steel a much smaller range of carbon impacts
than aluminium, as shown in Figure 9.
14
12
10
8
6
4
2
0
Aluminium
Steel
Figure 9 An indicative range of different product
stage emissions from two substitute products
Source: ICE, University of Bath, BSRIA (2011)
replacement cycle. In some circumstances, adaptability
and capacity for re-use may be more important
considerations than just achieving longevity. Figure 10
© BCO 2012
17
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Life (years)
70+
35–70
25–35
15–25
5–15
0–5
illustrates the different lifespans of components and
materials in a given building.
Figure 11 shows the sources of data to be used for
carbon assessment in the product stage. Issues to
consider when making the calculations, in order to
improve accuracy, include the wastage rates of raw
materials and the correct density of materials. The
Chartered Institution of Building Services Engineers
(CIBSE) Guide A19 provides useful guidance on this
information.
A1
Raw material
supply
+
Figure 10 Different lifespans of
components within a building
Source: Sturgis Associates (2009)
A2
Transport
raw material
+
A3
Manufacturing
=
Product
stage
(kg CO2e)
Embodied carbon:
• Inventory of Carbon & Energy (ICE)17
• BSRIA (2011)18
• http://www.bath.ac.uk/mech-eng/sert/embodied
Defra GHG conversion factors13
Figure 11 Data sources and calculation for the
product stage
Source: CECoP, data sources (2010)
CONSTRUCTION STAGE
The scope of the construction-stage emissions includes:
Construction stage
18
© BCO 2012
A4
A5
Transport
Site
works
This stage of the analysis describes the impacts arising
from transporting the construction products to site and
their subsequent processing and assembly into the
building. It also includes the carbon impacts associated
with the contractor and operatives delivering the project
(e.g. site huts, cranes, drying rooms and changing
facilities).
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Emissions from moving 1 kg of material 1 km
800
700
600
500
400
300
200
100
<37
<15
0
Boat
(container)
Lorry
(rigid HGV, gross
weight 3.5–7.5 T,
average weight
laden 43%)
Van
Air
(petrol gross weight (short-haul international
1.3 T, average weight
flight)
laden 37%)
Rail
(diesel/electric)
Figure 12 Comparison of carbon impacts arising from different transport modes
Source: Defra (2011)
Typically, most of these impacts are quite small. However,
for heavy materials used in large volumes, such as
concrete and aggregates, transport-related emissions
can be significant. Figure 12 shows a comparison of
the carbon impacts of different modes of transport.
It is worth noting that the values in Figure 12 relate
to the carbon impacts of moving 1 kg of material over
1 km. When making a decision on selecting a material,
it is necessary to consider where the product comes
from, as well as how it is transported.
Care should also be taken with the values given in
Figure 12 as they are averages for typical journeys. For
example, over long distances, transport by air may be more
efficient (per kg CO2e/km) than transport by, say, a van.
Although the impacts arising from the construction stage
are generally small, they should not be disregarded.
For instance, not running site generators throughout
the night, sourcing products locally and minimising
over-ordering can be simple means of reducing costs
and saving carbon on a construction project. WRAP
(Waste and Resources Action Programme) can
provide guidance for contractors and designers
on how to mitigate and manage these impacts.20
The sources of data to be used for carbon assessment
in the construction stage are shown in Figure 13.
A4
Transport
+
A5
Site
works
=
Construction
stage
(kg CO2e)
Defra GHG conversion factors13
Where direct information is not available, use price
and time estimates from the Environment Agency
carbon calculator21
Figure 13 Data sources and calculation for the
construction stage
Source: CECoP, data sources (2010)
© BCO 2012
19
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
IN-USE STAGE
The scope of the in-use stage emissions includes:
in the future, and this poses many problems related
to estimating the size of the impacts and when they
may occur.
In-use stage
B1
B2
B3
B4
In use
Maintenance
Repair
Replacement
B5
B6
B7
Refurbishment
Operational
energy use
Operational
water use
In the present report, a uniform 60-year assessment
window is used to evaluate all the whole-life impacts
associated with a building. This choice of time period
reflects the current convention among life-cycle
practitioners to study buildings for this length of time,
allowing findings from one study to be compared
directly with those obtained in other studies.
This is by far the most complex stage in the assessment,
and covers a wide range of emission sources associated
with the operation of the building, including heating,
lighting, cooling and small power demands. It also
features ongoing product and construction impacts
arising from the maintenance, repair and replacement
of the various components of the building. Finally, it
includes the carbon impacts arising from water usage
in the building.
However, while from a whole-life perspective these
impacts are significant, to occupiers they account for
only a small percentage of the cash flow for any given
workstation, typically only around 3–5% (Figure 14).
It is also important to appreciate that, at this stage, by
far the majority of these impacts (over 90%) will occur
However, there are a number of issues surrounding
this choice of assessment period, as current building
lifetimes can be as low as 18 years in some locations due
to high levels of functional and aesthetic obsolescence,
and occupier demands for the latest modern office
accommodation. In such circumstances, constructionand product-stage emissions will make up a much
greater proportion of the overall whole-life carbon
impacts, and the importance of the in-use stage may
become overemphasised.
Other uncertainties associated with the carbon impacts
arising from the in-use stage include the scale of the
decarbonisation of the national grid over the next
60 years. This may significantly change how we view
electricity as a source of energy, from being carbon
intensive, to a low carbon source in the years to
come. An indication of how the carbon intensity of the
Soft facilities management
(telephone and printing)
£650
Management
£170
Hard facilities management
(insurance, security and utilities)
£1370
Rent
£2070
3–5%
Costs relating to
carbon emissions
Rates
£750
20
© BCO 2012
Fittings
£820
Figure 14 Typical office occupational
costs (per workstation), 2010
Source: Actium Consult, The Total
Office Cost Survey (2010)30
Grid carbon intensity (kg CO2e/Kw) h)
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0
2010
2020
2030
2040
Year
national grid is anticipated to change is shown in
Figure 15.
Carbon savings on a project over a life cycle
(kg CO2e)
Understanding how the profile of in-use carbon impacts
will change over time is particularly important when
deciding on a portfolio of carbon-reduction technologies
for a particular project. The savings achieved, contingent
on the scale of national grid decarbonisation, with two
carbon-reduction alternatives are shown in Figure 16.
It can be seen that, if there is grid decarbonisation,
installing a ground-source heat pump will save the most
carbon. However, if no grid decarbonisation occurs,
the photovoltaic panels will save the most carbon.
80
70
60
50
40
30
20
10
0
Photovoltaic
panels
Ground source
heat pump
Figure 16 The carbon savings achieved with two
different methods over the life cycle of a building
Source: Sturgis Carbon Profiling (2011)
2050
2060
2070
Figure 15 The
decarbonisation trajectory
of the national grid.
Source: Craig Jones,
Embodied Carbon: A Look
Forward, Sustain (2011)
This is due to the savings being sensitive to changes
in grid carbon intensities. In the case of photovoltaic
panels, savings are generated by replacing grid
electricity with energy provided by the sun, so the less
carbon intensive the grid is, the less carbon is saved
by such replacement. However, with a ground-source
heat pump, electricity is used to pump refrigerant
through the heat exchanger to extract heat from the
earth. If grid decarbonisation occurs, less carbon is
emitted through the use of electricity to run the pump,
and therefore higher net carbon savings are achieved.
This example illustrates how specification decisions
may be contingent on broader issues that cannot be
controlled just by means of building design and use.
The management of energy use in buildings is also a
key way to control and minimise in-use carbon emissions.
Over the years, King Sturge (now JLL) and others have
made the observation that, by employing an energy
management system and using buildings more
efficiently (especially office buildings), it is possible
to increase the energy efficiency per person using
the building by more than 40%. A case in point is the
King Sturge (now JLL) office in Bristol (Figure 17),
where in 2008, as a result of employing an energy
management system, it was possible to reduce carbon
emissions by 40%. As a secondary benefit, such a
strategy will also result in a much better Display
Energy Certificate, as and when such certificates
become voluntary or mandatory for office buildings.
On a micro level, significant cumulative carbon savings
can be made by tackling items of equipment that
consume energy in their operation. A good example of
this is drying one’s hands, as shown in Table 1. It can
© BCO 2012
21
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table 1 Hand drying – an example of energy
reduction
DRYING METHOD
Figure 17 The King Sturge (now JLL) office building
in Bristol, where in 2008 the use of an energy
management system reduced the energy load by 40%
Source: King Sturge LLP (2010)
be shown that, if the average employee dries his hands
five times a day, the cumulative saving over the lifetime
of the building of switching from a standard electric dryer
to a Dyson Airblade or similar system would be more
than 1.25 t of carbon dioxide emissions per person.
A final issue to consider is that best practice is invariably
not achieved throughout a sample of a given building
type. This is illustrated in Table 2, taken from from the
CIBSE publication Energy Use in Offices,23 which
shows that across a sample of different office building
types, in-use emissions are 60–85% higher than in a
good-practice building.
CARBON EMISSIONS
(g CO2)
Letting them drip
0
Dyson Airblade
3
One paper towel
10
Standard electric dryer
20
Source: Office for National Statistics (2009); Small
World Consulting Ltd; Berners-Lee, How Bad Are
Bananas?22
Similarly, in many cases there is a wide disparity
between the design of a building and its actual
performance. For further information, see CarbonBuzz,24
which is producing a database on this issue.
Life Expectancy of Building Components, published by
the Building Cost Information Service,25 can be used
to help define the replacement and maintenance
intervals for components.
The sources of data to be used for carbon assessment
of the in-use stage are shown in Figure 18.
Table 2 Comparison between typical in-use carbon emissions and those achieved in good-practice offices
CARBON EMISSIONS (kg CO2/m2)
GOOD PRACTICE
TYPICAL
Smaller regional office (cellular)
32.2
56.8
Naturally ventilated (open plan)
43.1
72.9
Air-conditioned (open plan)
85
151.3
143.4
226.1
Headquarters (prestige)
Annual emissions of CO2 (CEI) (kg CO2/m2 of treated floor area) using CO2 emission factors of
0.19 kg CO2/kW h for gas and 0.52 kg CO2/kW h for electricity.
Source: CIBSE, Energy Use in Offices.23
22
© BCO 2012
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Carbon costs associated with looking after the building
B1
In use
+
B2
Maintenance
+
B3
Repair
+
B4
Replacement
+
B5
Refurbishment
+
B6
Operational
energy use
+
B7
Operational
water use
In-use
= stage
(kg CO2e)
Defra GHG conversion factors13
(Difficult to anticipate
unless specifically
known to operate as
a data centre, etc.)
Embodied carbon:
• Inventory of Carbon & Energy (ICE)17
• BSRIA (2011)18
• http://www.bath.ac.uk/mech-eng/sert/embodied
Environment Agency water/greywater26
(Acknowledging differences depending on
the location in the UK, so use is not ideal,
but it provides a starting point)
(Where direct information is not available, use
price and time estimates from the Environment
Agency carbon calculator21)
Figure 18 Data sources and calculation for the in-use stage
Source: CECoP, data sources (2010)
COMMUTING
The scope of the commuting emissions includes:
Commuting
Bus
Train
Car
By foot
As stated previously, in this report commuting impacts
are identified separately given the scale of the
contribution they make towards the overall carbon
footprint. This reporting practice also makes it easier
to define responsibilities and actions that will aid in
reducing the carbon footprint of a building.
The carbon impacts associated with commuting depend
greatly on the building location and occupants’ access
to transport. Given the different carbon intensities of
different modes of transport (Table 3), access to the
local transport infrastructure around a building can have
a significant impact on the overall commuting carbon
emissions arising from a given building.
© BCO 2012
23
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
In addition, work undertaken by King Sturge27 in this
area shows how the length of commute as well as the
choice of transport mode varies by location and by
occupant type.
See Appendix 2 for more information on commutingrelated carbon impacts.
The sources of data to be used for carbon assessment
of commuting are shown in Figure 19.
Table 3 Carbon emissions of various modes of transport
MODE OF TRANSPORT
CARBON EMISSIONS (g CO2e/passenger/km)
Minibus with 20 passengers
15
Typical London bus
150
Intercity rail
150
Underground/city metro
160
Small car, steady 60 mph (100 kph)
344
Average car, 60 mph (100 kph)
710
SUV – four-wheel drive, 60 mph (100 kph)
2240
Crawling in congestion
4400
Source: Office for National Statistics (2009); Small World Consulting Ltd; Berners-Lee, How Bad Are
Bananas?22
Bus
+
Train
+
Car
+
By foot
= Commuting
(kg CO2e)
Defra GHG conversion factors13
Figure 19 Data sources and
calculation for commuting
Source: CECoP, Data sources
(2010)
END-OF-LIFE STAGE
The scope of the end-of-life stage emissions includes:
End-of-life stage
C1
C2
C3
C4
Deconstruction
Transport
Waste
processing
Disposal
These impacts emerge from the eventual deconstruction
and disposal of the existing building at the end of its
24
© BCO 2012
life. Specifically, this stage covers the on-site activities
of the deconstruction contractors, the transport of the
redundant components and materials to the point of
processing, the emissions generated from processing,
and the emissions associated with the eventual disposal
of the processed materials and components.
A key point in this final part of the analysis is that no
residual carbon value/benefit is given to any of the
redundant materials. The reason for this is two-fold.
First, the emissions associated with the original
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
construction of the materials have already been put
into the atmosphere and cannot be removed. Second,
even if the original emissions could be removed, this
would give rise to a possible double counting, where
benefits could be claimed at the end of the building’s
whole-life footprint and then again at the product stage
of the next whole-life analysis that incorporates the
recycled materials into a new building.
able to apportion impacts far more accurately than
at present. In addition, it should be remembered that
the biodegradation of organic materials gives rise to
methane and other high CO2e gases, and these impacts
are likely to be quite significant.
The sources of data to be used for carbon assessment
of the end-of-life stage are shown in Figure 21.
One issue this generates is how to incentivise building
designers to create buildings that can be deconstructed
and the component materials easily recycled, when the
advantages of doing so are not counted within the scope
of the building’s whole-life assessment (a solution to
this is offered in the next section). In particular, an
understanding of these impacts has been brought
home in recent years in the City of London, where
some notable examples of complex construction
techniques dating from the 1970s have led to great
challenges in the deconstruction of buildings. The
former Leadenhall building, which was a hung slab
building (Figure 20), is a good example – demolition of
the floor slabs around the core had to start from the
bottom and proceed to the top of the building.
The present report has identified that there is a significant
lack of data on the emissions arising from the disposal
of construction waste materials in disaggregated form.
If such data were available, practitioners would be
C1
Deconstruction
+
C2
Transport
+
C3
Waste
processing
+
C4
Disposal
Figure 20 Deconstruction works on the old
Leadenhall building
Photograph: David Barrie (2009)
= End-of-life
stage
(kg CO2e)
Defra GHG conversion factors13
• WRAP Net Waste Tool28
• WRAP Site Waste Management Plans29
• Project-specific reports can give general
(Where direct information is not
available, use price and time
estimates from the Environment
Agency carbon calculator21)
guidance, additional source information
needed
Figure 21 Data sources and
calculation for the end-of-life stage
Source: CECoP, data sources
(2010)
© BCO 2012
25
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
AFTER-LIFE STAGE (NOT INCLUDED)
The after-life stage is not included as part of the main
whole-life carbon footprint of a building but, as mentioned
earlier, it can be used to provide an indication of any
future recycling benefits. The figures for this stage
should always be reported separately from the main
whole-life footprint figures, to avoid the issue of double
counting, as described previously. This additional
section allows ‘potential savings’ to be identified, and
indicates how much less carbon would be put into the
atmosphere due to the capacity to recycle the materials
from the building into new components in the future.
Its use allows attention to be brought to any design
(or construction) decisions that would limit future
re-use or recycling of material.
26
© BCO 2012
Examples of actions that would allow this separate
figure to be flagged up are:
I
I
I
the use of lime mortars, which allows brick to be
dismantled from a wall and reused
bolting steelwork, which allows for the potential
deconstruction and re-use of the steel
not choosing anodising as a finish on aluminium
sections, which allows the sections to be potentially
recycled in the future. (Anodising chemically changes
the nature of aluminium, giving it new properties and
making it very expensive and complex to recycle,
which as a result usually means that materials
are rejected.)
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
EXAMPLES
OVERVIEW
In this section, we illustrate generally how the wholelife carbon footprints of different office types compare,
and what factors contribute to the overall carbon
performance in each instance. Four typical UK office
types are considered:
I
I
I
Typical whole-life carbon footprint (kg CO2e/m2)
I
Central London, air-conditioned offices
Central Business District (CBD), Regional City,
air-conditioned offices
CBD, Regional City, non-air-conditioned offices
Out-of-Town Business Park, air-conditioned offices.
A summary of the typical carbon impacts of each office
type is shown in Figure 22. It can be seen from the
figure that it is the commuting and in-use emissions
that drive a large part of the difference between the
whole-life carbon emissions of the four building types.
The hatching over the in-use bar indicates the proportion
of the in-use emissions that arise, as a result of the
ongoing repair, maintenance and refurbishment of the
building, from the construction of new products throughout
the life of the building.
10,000
Commuting
8,000
End of life
In use
Construction
Product manufacture
8,100
8,000
6,800
6,000
5,600
4,000
2,000
0
Central London
air-conditioned
CBD Regional City
air-conditioned
CBD Regional City
non-air-conditioned
Out-of-Town
Business Park
air-conditioned
Figure 22 Summary of the typical carbon impacts of different office types
Source: Sturgis Carbon Profiling, King Sturge (JLL), BCO (2011)
BUILDING-TYPE DETAILS
Table 4 gives typical baseline carbon emissions values
(kg CO2e/m2) for each assessment stage for the four
office types considered, in order to provide an indication
of how a whole-life carbon footprint is produced.
© BCO 2012
27
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table 4 Typical baseline carbon emission values for the four office types considered
ASSESSMENT STAGE
Product stage
A1 Raw material supply
A2 Transport raw material
A3 Manufacturing
Total
Construction stage
A4 Transport product
A5 Site works
Total
In-use stage
B1 Operational energy use
(regulated)
B1 Operational energy use
(not regulated)
B2 Maintenance
B3 Repair
B4 Replacement
B5 Refurbishment
B6 Operational energy use
(maintenance)
B7 Operational water use
Total
Commuting
Transport by bus
Transport by train
Transport by car
Total
End-of-life stage
C1 Deconstruction
C2 Transport
C3 Waste processing
C4 Disposal
Total
TOTAL WHOLE-LIFE CARBON
Building variables
Floor area per person 15 m2
Full-time equivalents
1 per desk
CENTRAL
LONDON
AIR-CON.
(kg CO2e/m2)
CBD
REGIONAL CITY
AIR-CON.
(kg CO2e/m2)
CBD
REGIONAL CITY
NON-AIR-CON.
(kg CO2e/m2)
OUT-OF-TOWN
BUSINESS PARK
AIR-CON.
(kg CO2e/m2)
950
40
150
1140
800
30
150
980
750
30
120
900
800
30
150
980
25
40
65
25
35
60
25
35
60
25
35
60
2150
1650
800
1650
2365
1320
1120
1320
10
20
30
850
10
10
20
30
810
10
5
10
20
760
10
10
20
30
810
10
28
5463
28
3878
28
2753
28
3878
288
576
384
1248
288
384
1152
1824
288
384
1152
1824
288
144
2688
3120
15
20
10
5
50
7966
15
20
10
5
50
6792
15
20
10
5
50
5587
15
20
10
5
50
8088
Effective density
Life of building
15
60 years
Source: Sturgis Carbon Profiling, King Sturge (JLL), BCO (2011)
28
© BCO 2012
Note: Figures take account of
grid decarbonisation
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
DISCUSSION
EFFECT OF WORKPLACE PRACTICES ON WHOLE-LIFE
CARBON PERFORMANCE
One of the initial observations of this report is that the
way in which space is used has a significant effect on
the carbon performance of an asset. As the primary
function of an office is as a workplace for people, it
is contended that measuring carbon impacts on a per
person basis is more meaningful than measuring it
on a per area (square metre) basis. Buildings do not
generate carbon dioxide – it is the people using the
buildings who generate carbon dioxide.
Measuring carbon impacts by person usage helps ‘reward’
offices that are space planned efficiently, as measuring
carbon impacts on a square metre basis results in more
efficiently planned spaces being penalised by accruing
higher carbon impacts because of their increased
density of usage.
The potential to use spaces more efficiently has been
examined by King Sturge (now JLL), who concluded that
workplaces have the potential to be used much more
intensively. As can be seen from the split of the working
day for a range of office occupiers shown in Table 5, the
residual time that employees spend at their desk is
typically only around 40–60% of the average working
day, which would suggest that practices such as hot
desking could be an effective means of getting more out
of a space. In addition, space planning allowances in
The Total Office Cost Survey (TOCS) Survey (2010)30
still indicate a wide variety of allocations, up to as much
as 18 m2 person, which would also suggest that there
is a potential for gains to be made. The BCO researched
the ways in which people occupy their offices in 2009,
and found that people were occupying their space
much more intensively. (See the BCO Occupier
Density Report.31)
The effect of workplace practices on the carbon
performance of a building is illustrated here for the four
office types given earlier. Figure 23 shows how the carbon
footprint would change with more efiicient space planning
(increasing the density to 1 per 10 m2 from 1 per 15 m2)
and by increasing the amount of hot desking (increasing
the number of full-time equivalents from 1 per desk to
1.5 per desk). (See also Appendix 3.)
Table 5 The average ‘productive’ working day for occupiers of different office types*
MEAN TIME (hours:minutes)
CBD OFFICE
BUSINESS PARK
CALL CENTRE
Internal meetings
1:35
1:30
1:53
Travelling between meetings
0:40
0:54
0:41
Off-site client meetings
1:11
1:18
1:05
Out of the office (not included above)
0:40
0:32
0:41
Residual hours at desk
4:37
4:13
3:46
Total work day
8:43
8:27
8:06
*The survey excludes time allocated for lunch.
Source: King Sturge, Office Buildings: The Human Impact27
© BCO 2012
29
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Increased
density and
hot desking
Baseline
Baseline
Increased
density and
hot desking
Baseline
Increased
density and
hot desking
Baseline
Increased
density and
hot desking
119,000
83,000
102,000
72,000
84,000
62,000
121,000
91,000
kg CO2/person
kg CO2/person
kg CO2/person
kg CO2/person
kg CO2/person
kg CO2/person
kg CO2/person
kg CO2/person
Central London
air-conditioned
CBD Regional City
air-conditioned
CBD Regional City
non-air-conditioned
Out-of-Town
Business Park
air-conditioned
Figure 23 The impact of changes in workplace practices (values take into account grid decarbonisation)
Source: Sturgis Carbon Profiling, King Sturge (JLL), BCO (2011)
The more efficient use of commercial offices could
significantly reduce their carbon footprint without the
need for the introduction of complex technological
interventions such as solar photovoltaic panels or
renewable energy solutions. This suggests that buildings
should be dealt with in a more holistic sense, where
renewable energy solutions are targeted at buildings for
which efficient space-planning cannot be achieved (or
have difficult to treat fabric), such as historically listed
office buildings or buildings within a conservation area.
Table 6 illustrates how the carbon footprints of the four
different office types change as they are used more
intensively. As discussed previously, it is important to
consider these changes from a per person perspective.
One might believe that increased usage of office space
will give rise to more carbon emissions overall, but in
fact the carbon load per person may fall significantly
compared with the baseline data given in Table 4,
where the floor area is 15 m2 per person and the
full-time equivalent is 1 per desk.
THE IMPLICATIONS OF PRODUCTIVITY DIFFERENCES FOR
WHOLE-LIFE CARBON EMISSIONS
The second point of discussion in this report relates to
the introduction of effective legislation and incentives to
reduce carbon emissions from commercial offices. This
is a complex area, given the difference in productivity
between different office types. An incentive that works
well in one submarket in creating behavioural change
may quite possibly be an undue burden in another.
Consider as an example a call centre in a regional
location and the trading floor of a bank in Central
London. Both buildings may generate the same
carbon emissions, due to a similar consumption of
electricity for a given space. However, a carbon tax
(based on floor area, not on usage or economic
output) that is priced to incentivise change in the
bank’s trading floor in Central London may, when
levied on the regional call centre, give rise to a serious
burden for that business and may cause it to relocate
elsewhere, or to cease trading.
30
© BCO 2012
In such instances, the different levels of economic
output from the use of a given space will make the
case to adopt energy-efficiency measures more or
less compelling. Therefore, if the objective of carbon
legislation is to incentivise incremental reductions in
carbon emissions (to meet national and international
targets), the most efficient policy will use different
sized carrots and sticks, depending on the productivity
context of different organisations and buildings.
Furthermore, when we consider the cost estimates of
achieving the required carbon reductions from our built
environment, which range from £400 to £700 per m2,32
and that there is over 600,000,000 m2 of commercial
floor space in the UK,33 it is clear that decarbonising
the built stock of the UK is as much an economic
issue as an environmental one. Thus the only way to
accelerate decarbonisation is to consider both these
aspects at the same time.
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table 6 Typical whole-life carbon footprints of buildings when they are used more intensively
ASSESSMENT STAGE
CENTRAL
LONDON
AIR-CON.
(kg CO2e/m2)
CBD
REGIONAL CITY
AIR-CON.
(kg CO2e/m2)
Product stage
A1 Raw material supply
950
800
A2 Transport raw material
40
30
A3 Manufacturing
150
150
Total
1140
980
Construction stage
A4 Transport product
25
25
A5 Site works
40
35
Total
65
60
In-use stage
B1 Operational energy use
2150
1650
(regulated)
B1 Operational energy use
5311
2960
(not regulated)
B2 Maintenance
20
20
B3 Repair
20
20
B4 Replacement
30
30
B5 Refurbishment
850
810
B6 Operational energy use
10
10
(maintenance)
B7 Operational water use
64
64
Total
8455
5564
Commuting
Transport by bus
648
648
Transport by train
1296
864
Transport by car
864
2592
Total
2808
4104
End-of-life stage
C1 Deconstruction
15
15
C2 Transport
20
20
C3 Waste processing
10
10
C4 Disposal
5
5
Total
50
50
TOTAL WHOLE-LIFE CARBON
12,518
10,758
Building variables
Floor area per person 10 m2
Effective density 6.7
Full-time equivalents
1.5 per desk
Life of building
60 years
CBD
REGIONAL CITY
NON-AIR-CON.
(kg CO2e/m2)
OUT-OF-TOWN
BUSINESS PARK
AIR-CON.
(kg CO2e/m2)
750
30
120
900
800
30
150
980
25
35
60
25
35
60
800
1650
2510
2960
15
10
20
760
10
20
20
30
810
10
64
4189
64
5564
648
864
2592
4104
648
324
6048
7020
15
20
10
5
50
9,303
15
20
10
5
50
13,674
Note: Figures take account of
grid decarbonisation
Source: Sturgis Carbon Profiling, King Sturge (JLL), BCO (2011)
© BCO 2012
31
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
For the purpose of illustrating these ideas within the
context of this report, the economic output of the floor
area is assumed to be a multiple of 10 of the rent paid
for the given floor area. Our basis for taking rent as a
proxy for productivity is that the productivity advantage
of any one location over another is capitalised directly
in the rent, assuming that in the long run different
businesses can choose between different buildings
in order to occupy the location and space that allows
them to bid the highest in relation to the productivity
benefits it provides.
Secondly, our selection of a multiplier of 10 is based on
accounting guidelines, which suggest that, if an office
occupier’s property costs exceed 10% of the business
turnover, he is putting the business at a competitive
disadvantage by carrying too high overheads and
exposing the business to risk. (However, company
accounts typically also show office rents at or below
10% of the salaries of the occupants of a building;
therefore, more analysis and research may be needed.)
Finally, it is acknowledged that, in reality, the situation is
somewhat more complicated than stated here. However,
for the purpose of investigating the challenges of
legislating on carbon emissions for different buildings,
these assumptions are believed to be sufficiently robust.
Carbon/productivity ratio
(kg CO2e/person/£1000 GDP)
For further information on work that King Sturge (now
JLL) has undertaken on productivity, see Appendix 3.
To examine these and other issues relating to productivity
and carbon emissions, we have created a carbon
workplace productivity ratio, which expresses the
amount of carbon put into the atmosphere in relation
to the economic productivity achieved within a building.
Where this ratio is small, low amounts of carbon
emissions are generated per unit of productivity;
conversely, where this ratio is high, large amounts of
carbon emissions are generated per unit of productivity.
For legislators choosing an effective ‘price on carbon’,
the smaller this ratio becomes, the larger the carbon
tax would need to be if it is to be effective in driving
behavioural change, given the context of higher levels
of productivity in these types of buildings per unit of
CO2e created.
Figure 24 illustrates for the four building types considered
how this challenge may increase as buildings are used
more intensively (see also Appendix 3). The carbon/
productivity ratio in Central London is extremely small,
and thus a standard ‘carbon tax’ would act as a much
smaller incentive to undertake behavioural change
than it would for a non-air-conditioned, inefficient office
in a regional city, where rents are much lower.
Table 7 gives a detailed breakdown of the typical
productivity of the four office types considered, and
shows how it relates to the carbon emissions per
person over the life of the building. This simple
illustration suggests that a flat rate of tax on carbon
80
60
40
20
0
Baseline Increased
density
and hot
desking
Baseline
Increased
density
and hot
desking
Central London
air-conditioned
CBD Regional City
air-conditioned
Baseline Increased
density
and hot
desking
CBD Regional City
non-air-conditioned
Figure 24 Carbon productivity ratios for the four different office types
Source: Sturgis Carbon Profiling, King Sturge (JLL), BCO (2011)
32
© BCO 2012
Baseline
Increased
density
and hot
desking
Out-of-Town
Business Park
air-conditioned
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table 7 Carbon productivity ratios for the four different office types: detailed breakdown
CBD
CENTRAL LONDON
AIR-CON.
CBD
REGIONAL CITY
AIR-CON.
CBD
REGIONAL CITY
NON-AIR-CON.
OUT-OF-TOWN
BUSINESS PARK
AIR CON.
Productivity assesment stages (baseline)
Prime rent per m2
£500
£200
£140
£180
15
15
15
15
£7,500
£3,000
£2,100
£2,700
1
1
1
1
10
10
10
10
£75,000
£30,000
£21,000
£27,000
£4,500,000
£1,800,000
£1,260,000
£1,620,000
Floor space per person (m2)
Prime rent per person
Full-time equivalent
Turnover/person rent
Turnover (GDP)/person
Total GDP over lifetime
Built assests productivity of carbon emissions (kg CO2e/person/£1,000 GDP)
27
57
67
75
Source: Sturgis Carbon Profiling, King Sturge (JLL), BCO (2011)
emissions, such as the Climate Change Levy or the
proposed Carbon Reduction Commitment, could alone
be effective in driving the decarbonisation of buildings,
given the wide range of carbon productivity ratios. (A
CBD Central London air-conditioned office has a low
typical carbon footprint/productivity ratio of only 27
compared with the value of 75 for an Out-of-Town
Business Park air-conditioned building, although the
latter has a much lower level of indicative
productivity/GDP.)
If a carbon tax is priced such that it effectively drives
behavioural change in only one type of building, it will
effectively become regressive in nature. For example,
if the tax were to ignore high levels of productivity,
such as are found in Central London, it would unfairly
penalise the owners and occupying businesses of all
other buildings that are less economically productive.
An effect of this would be that occupiers of non-air-
conditioned buildings in regional cities, where market
values are lower, will pay more in a carbon tax (as a
proportion of their turnover) than occupiers of offcies in
Central London. Indeed, this was one of the effects of
the previous Fossil Fuel Levy (introduced in the
Electricity Act 1989, and repealed in 2000).
With regard to the future, it may be possible both to
accelerate the reduction in the carbon footprint of the
built environment (to help meet UK national targets),
and to reduce the burden on business, by linking any
carbon tax rate to the productivity of space. One solution
may be to introduce the carbon emissions of a building
part into a multiplier used in the calculation of any UK
Uniform Business Rate (UBR, an annual tax) liability for
commercial property. The UBR already reflects different
rental/productivity levels to some extent, and the
inclusion of carbon emissions in its calculation would
allow for a differential method of carbon tax pricing.
© BCO 2012
33
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
CONCLUSIONS
KEY FINDINGS
The reader is reminded that this is a scoping report,
outlining how the whole-life carbon footprint of an
office building is determined, and highlighting some of
the associated issues and implications for commercial
office buildings. Far more research and further analysis
is now needed.
We have illustrated the process through a series of four
different types of office in the UK, breaking down the
carbon impacts to show how they compare. Specifically
we have identified the following:
I
I
I
I
34
Out-of-town air-conditioned offices have the highest
carbon impacts due to the impact of transport to
and from the building, while naturally ventilated
regional offices have the lowest whole-life carbon
footprints (8100 and 5600 kg CO2e/m2, respectively,
in our examples).
With regard to the emissions relating to a building’s
component materials, construction and occupation,
Central London offices have the highest whole-life
carbon footprints. This is mainly due to more
carbon-intensive fit-outs and greater electricity
usage in offices in Central London than in offices
in other locations. However, this is not the whole
picture, as the effects of density and productivity
also play an important role (see below).
The largest single contributor to the whole-life carbon
emissions of a commercial building is the in-use
emissions (i.e. those generated from day to day,
such as heating lighting and cooling, and those
arising from the periodic maintenance, repair and
replacement of components throughout the lifetime
of a building).
Commuting drives a large part of the difference in
the carbon emissions between office types. The
examples show that, for a typical out-of-town office,
over 38% of the carbon impacts in the baseline
case are attributable to commuting, while the
comparable figure for a typical Central London
office is only 16%.
© BCO 2012
I
While London commuters typically travel longer
distances, they generally adopt more efficient
means of transport (i.e. they use more public
transport) than their regional counterparts, giving
them the lowest commuter transport emissions of
the four examples considered (even if they use a
car for part of their journey).
Building on these examples, we have discussed the
effects of changes in workplace practices, and have
advocated whole-life carbon reporting being made on
a per person basis as opposed to a per area (m2)
basis. Specifically, using the examples discussed
previously, we have identified the following:
I
I
I
The combined effect of increasing the occupier
density from 1 per 15 m2 to 1 per 10 m2 and
increasing the number of full-time equivalents
from 1 to 1.5 per workspace would be a decrease
in the whole-life carbon footprint of a typical Central
London office of 30%, typically from 119,000 to
83,000 kg CO2e/person. This remains true even
when the increased power usage, due to greater
air-conditioning requirements arising from higher
occupier densities, is taken into account.
In the case of out-of-town offices, the effect of
increasing the occupier density and the number
of full-time equivalents, as above, would be to make
the impacts associated with commuting in excess
of 50% of the total whole-life carbon footprint. This
finding suggests that integrating efficient transport
infrastructure with any out-of-town development
is particularly important from the perspective of
reducing carbon emissions perspective.
An issue that was not considered is that, as more
people use offices more flexibly, through higher
numbers of full-time equivalents allocated to each
space, these people will then be working in other
locations, such as their homes, where energy use
will increase directly as a result. As a consequence,
we believe this report may have overestimated
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
the benefit derived from the increased use of
space through desk sharing. However, the size
of this displacement effect is believed to be small,
given that home increases will only be attributable
to the power draws for laptops and, perhaps,
some lights.
We have also discussed some of the issues that
should be considered when drafting legislation on
carbon emissions, such as the proposed Carbon
Reduction Commitment – Energy Efficiency Scheme.
In particular we have noted the importance of setting
the correct tax level, given the wide range in productivity
of different office types. We conclude that:
I
I
I
The differences in the productivity of commercial
offices of different types across the UK are large,
and are set to increase further as buildings are
used more intensively.
Given the above, if applied on its own without
additional policy levers, a single price for carbon
emissions levied as a uniform tax is likely to be
ineffective at creating behavioural change. A single
price tax will fall disproportionally on some occupiers,
while being relatively insignificant for others.
The above course of action could lead to negative
unintended consequences for the occupiers and
owners of less productive buildings, especially
those located outside Central London.
OUTCOMES: SOME SUGGESTED ANSWERS FROM THIS RESEARCH
The Briefing Note and Terms of Reference for this
project asked for comments on the following items. The
comments should be read in the context of this report.
1. A simple but robust methodology for whole-life
carbon footprint measurement.
We have identified a method for this measurement,
and have identified a number of areas of further
research that will improve the accuracy of whole-life
carbon footprinting moving forwards.
2. Creating a competitive advantage in the EU.
This report highlights for BCO members some of
the issues that will need to be addressed if the EU
proceeds with ECO-labelling for all buildings.
avoid unintended longer term consequences for the
carbon footprint of a building.
5. Provide a framework for the property industry.
In this report we have established an initial, simple,
robust method for calculating the whole-life carbon
footprint of a building and the data that should be
used in the calculation. We assert that a series of
benchmarking exercises now needs to be undertaken
as a precursor to establishing embodied and
whole-life carbon legislation.
6. Prepare BCO members for the pending EU
ECO-labelling of buildings.
The answer to this is as 2 above.
3. Accelerating real estate decarbonisation to meet the
UK’s targets.
This report raises serious issues regarding carbon
taxation, if it is to be used in the built environment
to accelerate change. Likewise, it also suggests
that differentiated carbon subsidies may be more
effective in achieving decarbonisation across the
various UK regions.
4. Setting standards and raising awareness to avoid
unintended consequences.
This report highlights the determinants of a whole-life
carbon footprint for an office building, and establishes
some typical whole-life footprints for four basic office
types to aid generalised comparisons. We also provide
guidance on issues relating to overspecification, to
© BCO 2012
35
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
FUTURE RESEARCH
We make four key recommendations, raising questions
for future research:
I
Should the impacts of home working and other
displacement effects, which ‘off-shore’ the carbon
impacts of an organisation or building, be included
in the calculation of whole-life carbon?
Recommendation 1 – Benchmarking
In order to advise the BCO membership on how any one
building performs from a whole-life carbon perspective,
a benchmarking exercise should be undertaken for a
wide range of different office building types, including
existing and refurbished commercial buildings, which
make up the majority of the commercial stock in the UK.
Recommendation 2 – Ongoing checking
of assumptions
During the course of this study, it was necessary to
make various assumptions in order to carry out a
whole-life carbon assessment. However, many of
these assumptions may need to be kept under review,
as government policies and the way in which we use
offices change over time. In particular, we have
identified the following:
I
I
36
The decarbonisation of the national power grid will
affect whole-life carbon calculations (this has been
taken into account in the present study).
Is it appropriate to evaluate all buildings using a
reporting period of 60-years, when buildings in
different locations have very different anticipated
life-spans?
© BCO 2012
Recommendation 3 – Improvements in data
There is a need for a disaggregated data set (by waste
type) that identifies the ongoing carbon impacts of
construction waste once it has been sent to landfill. It
is believed that these emissions may form a significant
part of the whole-life footprint, given the large amounts
of damaging greenhouse gases, such as methane,
that may be generated, and the carbon footprint
of transportation.
Recommendation 4 – Related research topics
I
I
What would be a better method of measuring the
productivity of buildings (the economic sustainability),
especially in the public sector? While rent is a
useful indicator (in general, company accounts
show that rent is less than 10% of the total salary
cost of a building), there may be other methods
worth considering.
Greater integration of information technology,
human resource management and occupier
behaviour is required if significant improvements are
to be achieved in the whole-life carbon footprints of
office buildings.
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
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17. Inventory of Carbon & Energy (ICE). University of Bath. Available at: http://wiki.bath.ac.uk/display/ICE/Home+Page
(accessed 9 December 2011).
18. BSRIA (a consultancy, test, instruments and research organisation). Available at: http://www.bsria.co.uk (accessed
9 December 2011).
19. CIBSE. Guide A: Environmental Design. Available at: http://www.cibse.org/index.cfm?go=publications.view&item=1
(accessed 9 December 2011).
20. WRAP (Waste and Resources Action Programme). Available at: http://www.wrap.org.uk (accessed 9 December 2011).
© BCO 2012
37
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
21. Environment Agency. Carbon calculator. Available at: http://www.environment-agency.gov.uk/business/sectors/37543.aspx
(accessed 9 December 2011).
22. Berners-Lee M. How Bad Are Bananas? The Carbon Footprint of Everything. Profile Books, London, 2010.
23. CIBSE. Energy Use in Offices. Energy Consumption Guide 19. December 2000. Available at: http://www.cibse.org/pdfs/
ECG019.pdf (accessed 9 December 2011).
24. Carbon Buzz: http://www.carbonbuzz.org (accessed 9 December 2011).
25. Building Cost Information Service (BCIS). Life Expectancy of Building Components. A Practical Guide to Surveyors'
Experiences of Buildings in Use, 2nd edition. BCIS, London, 2006.
26. Environment Agency. Evidence. Energy and Carbon Implications of Rainwater Harvesting and Greywater Recycling.
Report SC090018, August 2010. Available at: http://publications.environment-agency.gov.uk/PDF/SCHO0610BSMQ-E-E.pdf
(accessed 9 December 2011).
27. King Sturge. Office Buildings: The Human Impact. King Sturge, London, 2003.
28. WRAP (Waste & Resources Action Programme). Net Waste Tool. Available at: http://www.wrap.org.uk/construction/tools_
and_guidance/net_waste_tool/the_role_of_the_net.html (accessed 9 December 2011).
29. WRAP (Waste & Resources Action Programme). Site Waste Management Plans. Available at: http://www.wrap.org.uk/
construction/how_do_i_reduce_waste/sectors/schools_construction/what_should_project_teams_do/swmps.html
(accessed 9 December 2011).
30. Actium Consult. The Total Office Cost Survey, 13th edition. Actium Consult, 2010.
31. British Council for Offices. BCO Occupier Density Study. May 2009. Available at: http://www.bco.org.uk (accessed 9
December 2011).
32. Miller V. The cost of going green. Building Magazine 2007.
33. Department of Communities and Local Government. UK Live Tables, 2011. Available at: http://www.communities.gov.uk/
corporate (accessed 9 December 2011).
34. MacKay DJC. Sustainable Energy – Without the Hot Air. UIT, London, 2008.
35. by Wastebusters Ltd. The Green Ofice Manual: A Guide to Responsible Practice, 2nd edition. Earthscan, London, 2000.
38
© BCO 2012
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
GLOSSARY
BCO
The British Council for Offices
Carbon When this report refers to ‘carbon’, it is
referring to the bundle of greenhouse gases (including
carbon dioxide), emitted as a result of human activities,
that cause damage to the atmosphere. The unit of
measurement is carbon dioxide equivalents (kg CO2e).
Its abbreviation in the text to ‘carbon’ is to aid the
report’s readability. Carbon dioxide equivalents are
explained more fully on page 12.
CBD
Central Business District.
CEN The European Committee for Standardization –
an organisation that is charged with writing and
publishing technical standards, which all EU member
states can use across all different areas of economic
activity.
Embodied carbon This term is used to describe the
carbon emissions associated with the making and
assembly of products and materials up to their designated
use. In the context of buildings, this would relate to
the emissions that have arisen in the making of the
walls, floors, windows, plant, roof etc. Maintenance
of a building would be included in this category.
Operational carbon This term relates to the carbon
emissions that arise during the use (i.e. operation) of a
building from the lighting, heating, cooling and power
used in day-to-day activities.
Renewables Items of technology, such as solar
panels, which are capable of generating energy from
sources that are not being depleted, and the use of
which, therefore, does not give rise to additional net
carbon being put into the atmosphere.
Whole-life carbon A whole-life carbon assessment
takes account of all the carbon emissions associated
with creating and using a building over its lifespan.
This includes the carbon associated with the production
of construction materials, their transport and assembly
on site, the emissions associated with a building’s
activities in-use, including maintenance and repair,
and the building’s eventual disassembly.
Regulated emissions These are building-related
carbon emissions that are controlled by various
statutory requirements, such as building control through
Part L of the Building Regulations. Regulated emissions
arise mostly from the heating, lighting and cooling of
a building.
Unregulated emissions These are building-related
carbon emissions that are not controlled by statutory
requirements, such as the emissions arising from
the delivery of construction materials to site and the
making of the building components in the first place.
CECoP The Construction Emissions Community of
Practice – this is a consensus data reporting framework,
as used in the IGT Report Low Carbon Construction.3
© BCO 2012
39
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
APPENDIX 1
THE CARBON FOOTPRINT OF A BUILDING
Table A1.1 sets out the potential components of
embodied energy for a typical office building.
Table A1.1 Components of the embodied energy of a
typical office building
COMPONENT
Roof
Mechanical and electrical –
ventilation and fit-out
% OF WHOLE
0.9
10.7
Cladding
8.4
Delivery vehicle
1.8
Lifts
1.2
Waste
1.8
Piling
4.1
Steel frame –
infrastructure and stairs
35.0
Concrete works
18.0
Table A1.2 The embodied energy of different
building types
BUILDING TYPE
EMBODIED CARBON
(kg CO2e/m2)
Office or retail
500–1000
House
800–1200
Raised floors
4.6
Flat
500–1000
Electricity/on-site office
4.2
Industrial
400–700
Walls and partitions
2.1
Road
130–650
Diesel used in plant machinery
and office electricity
5.2
Source: Howard NP. Embodied energy and
consequential CO2 in construction. Proceedings
of the 1996 International Symposium of CIBW67
on Energy and Massblown Buildings, Vienna,
August 1996.
Source: Faithful & Gould (based on University of
Bath research), New Civil Engineer, 1 October 2009.
40
There are a number of ways of measuring carbon, but
the most common is to look at the consumption of
carbon dioxide (plus other gases that cause damage
to the atmosphere). Table A1.2 provides some basic
comparisons of the carbon emissions associated with
constructing different building types. The values given in
the table show that appropriate design and specification
can lead to very large potential savings in embodied
energy. Note, however, that the figures in Table A1.2
were not compiled under the scope of the CEN/TC 350
calculation methodology outlined in this report, and so
direct comparisons are not advisable.
© BCO 2012
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
APPENDIX 2
TRAVELLING TO WORK
In 2003/4 Accessible Retail (the association of out-oftown retailers and property owners), with King Sturge
instructed IPSO-MORI to conduct a telephone survey
of 2,189 households. One of the questions related to
the use of car transport, plus distance and frequency
of travel. The results are shown in Figure A2.1, and it
can be seen that the dominant number relates to
travelling to or from work.
The data in Table A2.1 show the modes of transport
used to commute to work buildings, in terms of miles
travelled. Depending on the location of the workplace,
a considerable amount of time is also spent travelling to
and from work (Table A2.2). CBD offices are generally
less car-dependent than out-of-town offices, and it
can be seen from Table A2.1 that, of the business park
respondents, all used a car when commuting, and very
few used public transport. However, it can be seen from
Table A2.2 that more time is spent commuting to CBDs.
The data in Tables A2.1 and A2.2 were obtained in a
2003 UK survey of more than 2000 office buildings.
The data in Table A2.3 are from a 2006 Central London
survey, and this again illustrates the nature of office
Billion miles (000,000,000)
120
106.0
employment in relation to commuting time. Although
London is different from the rest of the UK, the total
travel time was similar in the two surveys; 62.18 min
for London (October 2006 survey, see Table A2.4)
and 45 min for the UK overall (2003 survey).
Although the number of respondents in Tables A2.3
and A2.4 is slightly different (due to the verifiable data
collected), one or two numbers stand out: surveyors
travel for far less time than partners; and, the more
senior the individual, the further he or she travels.
For all categories, travelling by train (whether above
or below ground) comprises an important element of
the commuting time. A far higher percentage of senior
staff use private cars at some point in their journey,
and in particular when travelling to and from their
home station. The use of buses and walking is more
common among associates and junior staff.
The above figures only relate to travelling in one
direction. Doubling the travel time shows that a
considerable amount of a working day is consumed by
travel. On average, 2 h and 20 min of the waking day
is spent travelling. Is this productive?
Base: All UK households interviewed (2,189)
100
80
54.9
60
42.4
33.8
40
28.6
20
17.9
16.0
Shopping:
retail parks/
large
warehouse
outlets
Taking
children
to/from
school
0
Travelling
to/from
work/station
Leisure
activities
Shopping:
out-of-town
centres
Shopping:
town/city
centres
Food/grocery
shopping:
hypermarket/
supermarket
Figure A2.1 Gross person-mileage per year by activity
Source: King Sturge (now JLL), IPSO-MORI for Accessible Retail (2003/4)
© BCO 2012
41
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table A2.1 Journey mode to work (UK office buildings)
TRANSPORT MODE FOR ALL OR
PART OF JOURNEY
SURVEY
AVERAGE
(%)
CBD OCCUPIERS
(%)
BUSINESS PARK
OCCUPIERS
(%)
CALL CENTRE
OCCUPIERS
(%)
Car
77.4
65.7
100.0
100.0
Tube – metro/tram
15.1
21.6
6.3
0.0
Bus
4.1
5.4
0.0
0.0
Motorbike
0.9
1.5
0.0
0.0
Walking
24.5
33.3
9.4
0.0
Train
20.4
28.9
3.1
0.0
Bicycle
1.3
2.0
0.0
0.0
Source: King Sturge, Office Buildings: The Human Impact27
Table A2.2 Average journey time to work (UK office buildings)
TRANSPORT MODE FOR ALL OR
PART OF JOURNEY
(% of survey average using mode)
SURVEY
AVERAGE
(min)
CBD OCCUPIERS
(min)
BUSINESS PARK
OCCUPIERS
(min)
CALL CENTRE
OCCUPIERS
(min)
Overall average journey time
45
50
36
30
Car (77.4%)
37
39
34
30
Tube – metro/tram (15.1%)
24
25
18
0
Bus (4.1%)
22
22
0
0
Motorbike (0.9%)
27
27
0
0
Walking (24.5%)
13
13
7
0
Train (20.4%)
41
42
30
0
Bicycle (1.3%)
14
14
0
0
Source: King Sturge, Office Buildings: The Human Impact27
The main message that emerges from this type
of analysis is that the office building should not be
seen in isolation. Staff are the most important and
valuable commodity of a business. Unless there
is an integrated approach to human resource
management, and the possibility, through an
information technology system, to work remotely,
inefficiencies will persist. While a telephone call
centre may have to be in a specific location, many
of the other types of office work could, for all or part of
the day, or part of a normal week, be undertaken
remotely. A ‘virtual office’ is an extreme version of this
type of arrangement.
Transport carbon is a key issue, and is not generally
included in the quantification of green building certificates,
although both LEED and BREEAM certificates do
recognise transport.* As shown in Figure A2.2, in terms
of energy per passenger, cycling is clearly far more
energy/speed efficient than public transport; and electric
cars and modern cars with two or more passengers
are more efficient than hybrid hydrogen fuel-cell cars.
*LEED (Leadership in Energy and Environmental Design) is the environmental assessment scheme of the US Green Building
Council, USA; BREEAM (Building Research Establishment Environmental Assessment Method) is the environmental
assessment scheme of the Building Research Establishment, UK.
42
© BCO 2012
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table A2.3 Time taken and mode of travel to work: (Central London)
NO.
USED*
NO. NOT
USED
MEAN†
(min)
SD
MINIMUM
(min)
MAXIMUM
(min)
44
240
14.59
9.18
4
50
Motor bike/scooter (3%)
8
276
21.88
16.02
10
60
Taxi (1%)
2
282
15
15
15
Bus (17%)
44
240
24.91
16.57
5
80
Train (59%)
153
131
40.21
27.79
4
255
Underground/ DLR (79%)
180
104
22.52
13.23
5
90
16
268
33.19
13.76
6
60
128
156
13.71
8.63
2
40
94
190
10.05
5.82
2
35
3
281
26.67
20.21
5
45
59.44
30.30
TRANSPORT MODE FOR ALL OR
PART OF JOURNEY
(% of survey average using mode)
Private car (17%)
Bicycle (6%)
Walking (50%)
Waiting/walking between modes (39%)
Other (1%)
Total
284
0
SD, standard deviation.
* Number of multi-mode respondents who selected each mode, and perhaps other modes, during their journey
to work – not all respondents answered all questions.
† The average mean time for a one-way journey to work is 59.44 min.
Source: Survey by Surrey University for internal research: King Sturge, March 2006
Table A2.4 Mode of travel by time and job type
TRANSPORT MODE
SURVEY
TOTAL
(231)
PARTNERS
(55)
ASSOCIATES
(58)
SURVEYORS
(51)
ALL OTHERS
(67)
Private car
3.36
7.91
1.98
1.94
1.91
Motor bike/scooter
0.82
0.36
1.29
1.47
0.30
Bus
4.47
2.36
5.09
3.53
6.37
Train
25.93
32.20
23.76
15.37
30.70
Underground/DLR
12.73
12.82
11.69
11.63
14.40
Bicycle
2.28
2.45
2.67
2.98
1.27
Walking
9.33
7.40
8.66
11.06
10.19
Waiting/walking between modes
3.07
3.87
3.38
2.27
2.76
Other
0.17
0.00
0.34
0.00
0.30
62.18
69.38
58.86
50.25
68.21
Total travel time
Source: Survey by Surrey University for internal research: King Sturge, October 2006
© BCO 2012
43
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
900
800
Speed (km/h)
Energy consumption (kW h/100 km)
1000
700
600
500
400
300
200
100
ll)
ft
(fu
7
rc
74
ai
Bo
ei
ng
op
pr
Tu
r
bo
-s
hi
c
El
ec
tri
ra
ll)
ed
pe
d
ee
h-
ig
lh
se
D
ie
(fu
ll)
ll)
(fu
c
tri
ec
sp
gh
ca
n
El
H
fu
tra
in
r
)
ge
ro
yd
(2
ar
C
U
nd
H
er
yd
gr
ro
ou
ge
n
nd
fu
El
el
ec
pe
tri
ce
c
ll
rs
ca
on
r
ar
C
ca
r
s
Bu
in
tra
ro
/m
et
C
yc
Tr
am
le
0
Figure A2.2 Speed of travel and energy per passenger (unless indicated otherwise) of various transport modes
Source: MacKay, Sustainable Energy – Without the Hot Air33
Table A2.5 Carbon-emission indicators by mode
of travel
MODE OF TRAVEL
ENERGY USAGE
PER MILE
TRAVELLED
Bus per passenger
20 passengers on minibus
Typical London bus
15 g CO2
150 g CO2
Train per passenger
TRANSPORT
MODE
CO2 per km (kg)
UNIT
Bus
1.28
Vehicle km
Petrol car
0.20
Vehicle km
Diesel car
0.12
Vehicle km
Short haul flight
0.18
Passenger km
Tube
0.11
Passenger km
Intercity rail
150 kg CO2
Long haul flight
0.11
Passenger km
Underground/city metro
160 kg CO2
Rail
0.06
Passenger km
Car per passenger
Source: DETR (1999)
Small car, steady 60 mph (100 kph)
344 g CO2
Average car, 60 mph (100 kph)
710 g CO2
SUV: for-wheel drive,
2240 g CO2
60 mph (100 kph)
Crawling in congestion
4400 g CO2
Source: ONS (2009); Small World Consulting Ltd;
Berners-Lee, How Bad are Bananas?22
44
Table A2.6 The Green Office Manual CO2 emissions
by transport mode
© BCO 2012
While electric high-speed rail appears efficient, the figure
does not take into account the large negative carbon
footprint of new rail tracks (and tunnels). In other words,
David Mackay’s excellent analysis34 ignores the carbon
footprint of the energy embodied in the making (and
disposing of) the transport system. However, the data
do show that a full jumbo jet is more efficient per mile
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
travelled than most cars. Other indicators of transportrelated carbon emissions are listed in Table A2.5.
The energy used in travelling to and from a particular
building, whether it be an office building, retail or
residential or any other use, varies. The Green Office
Manual35 provides a framework for understanding
this concept, based on work published by the DETR
(Table A2.6). It can be seen from the table that, not
surprisingly, a bus (which is multiply occupied) creates
much less carbon dioxide per person travelling than
does petrol-driven car. Perhaps surprisingly, the carbon
dioxide generated by travelling by underground railway
(per km) is the same as that generated by a long-haul
aircraft flight (per km).
© BCO 2012
45
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
APPENDIX 3
REPORT WORKSHEETS
This appendix contains the calculation worksheets
used in the examples section of this report. The
information in the tables is taken from previous
46
© BCO 2012
projects undertaken by Sturgis Carbon Profiling and
King Sturge (now JLL) using the sources of data
identified in this report.
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table A3.1 Baseline
ASSESSMENT STAGE
CENTRAL
LONDON
AIR-CON.
CBD
REGIONAL CITY
AIR-CON.
CBD
REGIONAL CITY
NON-AIR-CON.
Building variables
Floor area person
15
15
15
Full-time equivalents 1 per
1.0
1.0
1.0
Effective density
15
15
15
Life of building
60
60
60
2
Whole-life carbon assessment stages (all expressed in kg CO2e/m )
Raw material supply
950
800
750
Transport raw material
40
30
30
Manufacturing
150
150
120
Product manufacture total
1140
980
900
Transport product
25
25
25
Site works
40
35
35
Construction stage total
65
60
60
Maintenance
10
10
5
Fit-out(s)
240
220
220
Repair
20
20
10
Replacement
30
30
20
Refurbishment
620
600
550
Operational energy use
2150
1650
800
(regulated sources)
Operational energy use
2365
1320
1120
(non-regulated sources)
Operational water use
28
28
28
In-use stage total
5463
3878
2753
Deconstruction
15
15
15
Transport
20
20
20
Waste processing
10
10
10
Disposal
5
5
5
End-of-life stage total
50
50
50
Transport by bus
288
288
288
Transport by train
576
384
384
Transport by car
384
1152
1152
Commuting total
1248
1824
1824
Total whole-life carbon
kg CO2e/m2
7,966
6,792
5,587
kg CO2e/person
119,495
101,885
83,810
Productivity assessment stages
Prime rents per m2
£500
£200
£140
Floorspace per person
15
15
15
Prime rents per person
£7,500
£3,000
£2,100
Full-time equivalent
1
1
1
Turnover/person rent
10
10
10
Turnover (GDP)/person
£75,000
£30,000
£21,000
Total GDP over life time
£4,500,000
£1,800,000
£1,260,000
Built assets productivity of carbon emissions (kg CO2e/person/£000 GDP)
27
57
67
OUT-OF-TOWN
BUSINESS PARK
AIR-CON.
15
1.0
15
60
800
30
150
980
25
35
60
10
220
20
30
600
1650
1320
28
3878
15
20
10
5
50
288
144
2688
3120
8,088
121,325
£180
15
£2,700
1
10
£27,000
£1,620,000
75
47
WHOLE-LIFE CARBON FOOTPRINT MEASUREMENT AND OFFICES
Table A3.2 Increased density and hot desk
ASSESSMENT STAGE
CENTRAL
LONDON
AIR-CON.
CBD
REGIONAL CITY
AIR-CON.
CBD
REGIONAL CITY
NON-AIR-CON.
OUT-OF-TOWN
BUSINESS PARK
AIR-CON.
10
1.5
7
60
10
1.5
7
60
750
30
120
900
25
35
60
5
220
10
20
550
800
800
30
150
980
25
35
60
10
220
20
30
600
1650
2520
2970
64
4189
15
20
10
5
50
648
864
2592
4104
64
5564
15
20
10
5
50
648
324
6048
7020
9,303
62,018
13,674
91,158
£140
10
£1,400
1.5
23
£70,875
£180
10
£1,800
1.5
23
£91,125
Total GDP over life time
£15,187,500
£6,075,000
£4,252,500
Built assets productivity of carbon emissions (kg CO2e/person/£000 GDP)
5
12
15
£5,467,500
Building variables
Floor area person
10
10
Full-time equivalents 1 per
1.5
1.5
Effective density
7
7
Life of building
60
60
Whole-life carbon assessment stages (all expressed in kg CO2e/m2)
Raw material supply
950
800
Transport raw material
40
30
Manufacturing
150
150
Product manufacture total
1140
980
Transport product
25
25
Site works
40
35
Construction stage total
65
60
Maintenance
10
10
Fit-out(s)
240
220
Repair
20
20
Replacement
30
30
Refurbishment
620
600
Operational energy use
2150
1650
(regulated sources)
Operational energy use
5321
2970
(non-regulated sources)
Operational water use
64
64
In-use stage total
8455
5564
Deconstruction
15
15
Transport
20
20
Waste processing
10
10
Disposal
5
5
End-of-life stage total
50
50
Transport by bus
648
648
Transport by train
1296
864
Transport by car
864
2592
Commuting total
2808
4104
Total whole-life carbon
kg CO2e/m2
12,518
10,758
kg CO2e/person
83,453
71,718
Productivity assessment stages
Prime rents per m2
£500
Floorspace per person
10
Prime rents per person
£5,000
Full-time equivalent
1.5
Turnover/person rent
23
Turnover (GDP)/person
£250,125
48
£200
10
£2,000
1.5
23
£101,250
17