Handbook of Sustainable Refurbishment

PPC live area 246x189mm, Spine 17mm, bleed 18mm

An incisive book that provides practical strategies and tactics for sustainable refurbishment, literally fromthe ground up. Richly illustrated with informative diagrams, supported by accessible quantitative analysisand reinforced by detailed case study examples, this book is a triumph.Koen Steemers PhD RIBA/ARB, Professor of Sustainable Design and Head of the Department ofArchitecture, University of Cambridge

Nick Baker tackles head on what many eminent scientists in Cambridge regard as most pressingcontemporary problems, the sustainable refurbishment of the existing building stock, much of which isgoing to be with us still in 2050. Dr Baker delivers his profound understanding of these difficult issues in awholly intelligible and compelling way. I cannot commend this book to my profession and its patrons highlyenough.Professor Alan Short, University of Cambridge and Short and Associates Architects

The refurbishment of existing buildings is a crucial yet often neglected subject within sustainable architecture attention is usually focused on new buildings. Many old buildings waste large amounts of energy andprovide poor internal conditions for occupants through poor lighting, poor ventilation, solar penetration andglare, and poor control of heating and cooling. Demolition is an option but the refurbishment alternative isincreasingly seen as more sustainable in terms of architectural value, materials use, neighbourhooddisruption and waste disposal. In addition, the potential impact of low energy refurbishment is much greaterthan that for new build since there are many more buildings already in existence than will be built in the next1020 years, the period over which many CO2 targets apply.

The Handbook of Sustainable Refurbishment: Non-Domestic Buildings offers architects, engineers and awide range of building professionals practical advice, illustrated by real examples. It moves from principles ofsustainable refurbishment to specific design and engineering guidance for a variety of circumstances. Itemphasizes the need for an integrated approach by showing how refurbishment measures interact with oneand other, and with the occupants, and how performance is ultimately influenced by this interaction.

Nick V. Baker is an independent consultant and technical expert on the energy efficient refurbishment andthe development of LT software. He is affiliated to The Martin Centre, Department of Architecture, Universityof Cambridge.

Architecture/Engineering

The Handbook of SustainableRefurbishment Non-Domestic Buildings

Nick V. Baker

TheHandbookof Sustainable Refurbishment Nick V. Baker

www.earthscan.co.uk

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. Baker

The Handbook of Sustainable Refurbishment

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The Handbook ofSustainable Refurbishment

Non-Domestic Buildings

NickV. Baker

Earthscan works with RIBA Publishing, part of the Royal Instituteof British Architects, to promote best practice and quality

professional guidance on sustainable architecture.

London Sterling,VA

3456 EARTHSCAN Hndbk Sust (RIBA):Layout 1 31/7/09 15:56 Page iii

First published by Earthscan in the UK and USA in 2009

Copyright NickV. Baker, 2009

All rights reserved

ISBN: 978-1-84407-486-0

Typeset by FiSH Books, LondonCover design byYvonne BoothGraphics by Mike J.V. Baker

For a full list of publications please contact:

EarthscanDunstan House14a St Cross StLondon, EC1N 8XA,UKTel: +44 (0)20 7841 1930Fax: +44 (0)20 7242 1474Email: [email protected]: www.earthscan.co.uk

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Earthscan publishes in association with the International Institute for Environment and Development

A catalogue record for this book is available from the British Library

Library of Congress Cataloging-in-Publication DataBaker, Nick (NickVashon)The handbook of sustainable refurbishment : non-domestic buildings / NickV. Baker.p. cm.

Includes bibliographical references and index.ISBN 978-1-84407-486-0 (hardback)1. BuildingsRepair and reconstruction. 2. Public buildingsRepair and reconstruction.3. Commercial buildingsRemodeling. 4. Sustainable buildingsDesign and construction. I.Title.TH3401.B35 2009690.24dc22

2009007564

At Earthscan we strive to minimize our environmental impacts and carbon footprint through reducing waste, recyclingand offsetting our CO2 emissions, including those created through publication of this book. For more details of ourenvironmental policy, see www.earthscan.co.uk.

This book was printed in Malta by Gutenberg Press.The paper used is FSC certified and the inks are vegetable based.

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Preface..................................................................................................................xi

List of Acronyms and Abbreviations ..............................................................................xii

Part One Principles1 Strategy for Low Emission Refurbishment................................3

1.1 The case for low emission refurbishment: Energy use in buildings ..................3

1.2 Refurbishment versus rebuild: Economics and environmental impact .............3

1.3 The building, plant and occupants as a system ................................................4

1.4 Implications for change of use........................................................................5Impact on energy consumption ................................................................6

1.5 Environmental comfort standards ...................................................................7

1.6 Passive environmental strategies......................................................................8Natural ventilation....................................................................................9Daylighting.............................................................................................10

1.7 Prioritizing refurbishment options ..............................................................13Quantifying energy benefits....................................................................14

1.8 Integration with newbuild ..........................................................................18

1.9 Eco-communities and urban renewal .........................................................19

1.10 Environmental regulation.............................................................................20Energy Performance of Buildings Directive.............................................20Using other legislation in the UK...........................................................22Voluntary schemes and drivers ................................................................22

Part Two Practice2 Floors .................................................................................27

2.1 Solid ground floors ......................................................................................27Insulation options ..................................................................................27Underfloor heating or cooling ................................................................27

2.2 Suspended ground floors..............................................................................28Insulation options ...................................................................................28Underfloor heating or cooling ................................................................28

Contents

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2.3 Intermediate floors ......................................................................................29

2.4 Thermal response implications of floor insulation.........................................29

3 Walls ..................................................................................313.1 Solid walls ...................................................................................................31

External insulation .................................................................................31Implications for external insulation .........................................................32Internal insulation...................................................................................33Thermal response ...................................................................................33Cold bridges...........................................................................................33Interstitial condensation..........................................................................34

3.2 Cavity walls .................................................................................................35Insulation options ...................................................................................35Practical considerations ...........................................................................36Interstitial condensation..........................................................................36Thermal implications..............................................................................37Retrofit inner or outer leaf .....................................................................37

4 Roofs................................................................................................39Roof types .............................................................................................39

4.1 Insulating roofs with attic spaces...................................................................40Ventilation of attic space .........................................................................40

4.2 Insulating roofs with voids ...........................................................................40

4.3 Insulating solid roofs ....................................................................................41Insulation above the waterproof membrane.............................................41Insulation between waterproof membrane and structural deck ................42Insulation below the structural deck........................................................43

4.4 Other thermal issues ....................................................................................43Surface reflectance ..................................................................................43Low-emissivity membranes in cavities.....................................................44Thermal mass .........................................................................................44Cold bridges...........................................................................................45

4.5 Green roofs and roof ponds..........................................................................45Green roofs ............................................................................................45Roof ponds ............................................................................................46

5 Windows ...........................................................................................47

5.1 Glazing materials .........................................................................................47Heat transmission through glazing ..........................................................48Radiation transmission through glazing...................................................50High performance glazing ......................................................................50

5.2 Framing and support systems .......................................................................51Obstruction of light due to framing ........................................................52

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Thermal performance of framing............................................................53Framing material ....................................................................................54

5.3 Modifying apertures.....................................................................................55

5.4 Shading systems ...........................................................................................56Daylight redistribution............................................................................56Shading options for refurbishment ..........................................................57External shading .....................................................................................57Internal shading......................................................................................59

5.5 High performance daylighting .....................................................................60

6 Atria and Double Skins ......................................................................63

6.1 Atria and energy: Principles .........................................................................65Thermal performance.............................................................................65Winter performance ...............................................................................65Summer performance .............................................................................67

6.2 Effect on daylighting ...................................................................................67

6.3 Planting and vegetation................................................................................68

6.4 Double skins and energy ..............................................................................68

6.5 Other environmental factors ........................................................................68

6.6 Atria and double skins as part of sustainable refurbishment ...........................69

7 Mechanical Services and Controls ........................................................71

7.1 Boilers .........................................................................................................71

7.2 Heat distribution .........................................................................................72Water .....................................................................................................72Air .........................................................................................................72

7.3 Heat emitters ...............................................................................................73Positioning emitters ................................................................................75Sizing emitters........................................................................................75Coolth emitters ......................................................................................76

7.4 Fans and pumps ...........................................................................................76

7.5 Refrigeration...............................................................................................77

7.6 Lighting installations ....................................................................................77Luminous efficacy...................................................................................77Illuminance level and distribution ...........................................................79

7.7 Controls ......................................................................................................79Local control ..........................................................................................79Central control .......................................................................................80Zoning ...................................................................................................80

7.8 Lighting controls..........................................................................................81Occupancy detection..............................................................................81

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Daylight detection ..................................................................................82Zoning ...................................................................................................83Energy savings ........................................................................................83

7.9 Building energy management systems ..........................................................83

7. 10 Adaptive controls .........................................................................................84Feedback ................................................................................................85Caretaker controls...................................................................................86

7.11 Hybrid and mixed mode systems .................................................................86

8 Renewable Energy Options .................................................................89

8.1 Other renewable energy technologies ..........................................................89

Part Three Case Studies9 The Albatros, Den Helder,The Netherlands ..........................................93

Objectives..........................................................................................................93Refurbishment strategy ................................................................................93

The double skin.................................................................................................94Performance of double skin ..........................................................................96

Ventilation and heating ......................................................................................96Performance.................................................................................................97

Daylighting........................................................................................................98

Overall energy performance...............................................................................98

Comfort ..........................................................................................................100

Conclusions .....................................................................................................100

10 Lyce Chevrollier,Angers, France ......................................................101

Strategy for sustainable refurbishment...............................................................101

Main low energy measures ...............................................................................102A.Thermal .................................................................................................102B. Lighting .................................................................................................102C. Comfort: Shading and ventilation...........................................................102D.Other features ........................................................................................102

Insulation.........................................................................................................102

Daylight and artificial lighting ..........................................................................103Artificial lighting ........................................................................................103Performance...............................................................................................104

Ventilation .......................................................................................................104Performance...............................................................................................104

The atrium ......................................................................................................105

Photovoltaic panels ..........................................................................................106

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Waste management and other environmental issues ..........................................106

Overall energy performance.............................................................................107Gas consumption .......................................................................................107Electricity consumption .............................................................................107CO2 emissions............................................................................................107

Comfort ..........................................................................................................108

Conclusions .....................................................................................................109

11 Daneshill House, Stevenage, UK .........................................................111

Strategy for refurbishment................................................................................111

Main innovative energy-saving features ............................................................112The CoolDeck system................................................................................112Performance...............................................................................................113

Energy efficient air-conditioning controls ........................................................114Performance...............................................................................................114

Energy-efficient lighting controls .....................................................................114Performance...............................................................................................115Light emitting diode (LED) lighting in Customer Service Centre ...............116

Solar water heating array..................................................................................118Performance...............................................................................................118

Increased space use efficiency ..........................................................................119

Post occupancy evaluation................................................................................120

Overall energy performance.............................................................................121

12 Ministry of Finance Offices,Athens ....................................................123

Refurbishment strategy ....................................................................................123

Main energy saving features .............................................................................124Fabric improvements ..................................................................................124Night ventilation techniques.......................................................................124Ceiling fans ................................................................................................124Daylighting and artificial lighting................................................................124Heating ......................................................................................................124Cooling......................................................................................................124Ventilation..................................................................................................124Energy management, control and monitoring .............................................125

Performance ....................................................................................................125Thermal comfort and air quality.................................................................125Daylighting and artificial lighting................................................................127Daylighting performance ............................................................................127

The photovoltaic array .....................................................................................127

Overall energy performance.............................................................................127Heating ......................................................................................................128

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Cooling......................................................................................................128

Comfort surveys ..............................................................................................128

13 The Meyer Hospital, Florence ............................................................131

Refurbishment strategy ....................................................................................131The greenhouse .........................................................................................132Daylighting ................................................................................................134

Overall energy performance.............................................................................134

Comfort ..........................................................................................................134

Appendices .........................................................................................................135

Index ................................................................................................................165

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In most European cities there is a vast stock ofexisting buildings, many of which are getting tothe end of their useful life.To replace the stockwould take several decades and incur an unreal-istic financial burden. It would also create a largecontribution to CO2 emissions, as a result of theenergy associated with the production ofmaterials and the construction of replacementbuildings.

It is therefore essential that we developstrategies and techniques to improve the energyperformance of our existing stock. It is commonlyunderstood that the heating, cooling, lighting andventilation of buildings accounts for nearly half ofglobal energy consumption,with the consequentCO2 emissions having an effect on global warm-ing.The reduction of day-to-day consumption offossil fuels for heating, cooling, lighting and ven-tilation must be the main objective in any attemptto refurbish a building sustainably.

This guide is a product of the EuropeanUnion (EU) funded REVIVAL project, whichset out to demonstrate some of these principlesby incorporating them in five refurbishmentprojects of large non-domestic buildings.Wher-ever possible it draws from the experience of theREVIVAL project, but includes other examplesand illustrations when necessary.

This guide is aimed at the architect, engineer,surveyor and project manager. It sets out the casefor sustainable refurbishment and the principlemeasures that can be adopted. It presents princi-ples in a concise technical language, but followswith an explanation of practical implications. Itdoes not attempt to be a source book of manu-facturers information and technical data, or todeal with construction detail.

REVIVALTeamJuly 2009

Preface

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AC air-conditionedANV advanced natural ventilationBEMS building energymanagement

systemsBREEAM Building Research Establishment

Environmental AssessmentMethod

CHP combined heat and powerCRC Carbon Reduction CommitmentCOP Coefficient of PerformanceCSR Corporate Social ResponsibilityDEC Display Energy CertificateDEFRA Department for Environment,

Food and Rural AffairsDF daylight factorDX direct expansionEEAS Energy Efficiency Accreditation

SchemeEPBD Energy Performance of Buildings

Directive

EPC Energy Performance CertificateEU European UnionIR infraredIRC internally reflected componentLED light emitting diodel/w luminaires per wattMM mixed modeNV natural ventilationPAC partially air-conditionedPCM phase change materialPIR passive infraredPSALi permanent supplementary

artificial lightingPV photovoltaicSBS sick building syndromeSHF Solar Heat Gain FactorUV ultraviolet

List of Acronyms and Abbreviations

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Part One Principles

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1.1 The case for low emission refurbishment:Energy use in buildings

In the non-domestic sector in Europe, buildingrefurbishments offer far more opportunities forreducing emissions than new building; the latterrepresents annually less than 1.5 per cent of thebuilding stock.The usual motivation for refur-bishment includes:

replacement of degraded finishes andcomponents;

tailoring space organization to new uses; improving environmental quality.

These reasons may be sufficient in themselves tojustify the cost. If at the same time the buildingcan be made more energy efficient, there will bea reduction in running cost and a reduction inCO2 emissions.This will often be at a modestextra cost that can be justified by reduced run-ning costs, or in some cases even, no extra cost.

1.2 Refurbishment versus rebuild:Economics and environmental impact

There are many instances when demolition andrebuild will be considered as an alternative to re-furbishment. This could be justified purely oneconomic grounds, or the advantages offered bya new building could be considered to justify theextra cost. However, two non-economic factorsshould be considered:

1 The environmental impact of refurbish-ment versus newbuild.

2 The socio-economic impact.

Initially, the environmental impact of refurbish-ment will almost always be less than demolitionand newbuild.This is because all the materialscarry embodied energy to replace them causesnew carbon emissions (Figure 1.1). Furthermore,the demolition process and waste disposal cre-ates carbon emission as well as other wastedisposal impacts.

Strategy for LowEmission Refurbishment1

0 10 20 30 40

roof covering

internal partions

raised floors

concrete

steel

piling

cladding

M&E

site energy

deliveries

waste

% total

Embodied CO2

Figure 1.1 Embodied CO2 associated with newbuild andrefurbishment. Note large CO2 content for bulk materialssuch as concrete and steel. Components made of thesematerials are the ones that are not normally replaced inrefurbishment

Source: Thomas Lane quoting the Simons Construction Group in Our darkmaterials, Building, 9 November 2007


It is often argued that a new building will oper-ate at higher energy performance than arefurbished one, and that during its lifetime,mayhave less environmental impact.This dynamic re-lationship is shown in Figure 1.2. It demonstratestwo important effects that newbuild is only thelowest emitter after the break-even time period,and that this period can be extended by im-proved performance of the refurbished option. Italso demonstrates that if the break-even time isbeyond the time of the environmental crisis (oremission reduction target), the life-cycle emis-sion is irrelevant and the refurbished building isthe best choice. It is also evident that the break-even point is sensitive to the actual performanceof the buildings; new buildings have not in gen-eral performed as well as predicted and this willpostpone the break-even point.The second consideration is about social benefitand employment. Generally, refurbishment car-ries a higher proportion of labour cost thannewbuild. For example, the repair of a concrete

structure and the cleaning of concrete finisheswill direct money to tradesmen that in the caseof new build would go to investors in concreteand steel manufacture.

1.3 The building, plant, and occupants as asystem

Building simulations and analyses of monitoreddata have shown that the building fabric alonedoes not narrowly determine the energy per-formance. Figure 1.3 shows the performancebeing determined by three sub-systems, eachhaving a variance in performance of about two-fold.When a poor building combines with badlydesigned systems and poor management, the re-sulting energy performance can be dramaticallyworse than the best.This wide variation of per-formance has been observed as shown in Figure1.4. It is interesting to note that building no. 92(extreme right) was built in 1987 and refurbishedin 1992.

4 Principles

Figure 1.2 CO2 emissions fornewbuild and refurbishment as afunction of time. The break-even pointis very dependent upon the differencein performance (indicated by the slopeof the graph) of the refurbished andnewbuild.

building

x 2.5*

services

x 2.5

occupants

x 2.5

environmentalperformance

x 16maximum rangeof performance

Figure 1.3 The building, the mechanicalservices and the occupants, as a system. Eachcontrols a range of performance. A poorbuilding may require much input fromservices which if badly managed leads to highenergy consumption. The reverse may also betrue. This accounts for a wide variance inenergy consumption of similar buildings


This evidence weakens the case for newbuild,since it shows that the inherent properties of thebuilding are only one of the determining factors.This is particularly true in non-domestic build-ings where overall energy consumption isdominated by processes and activities in thebuilding. Both systems and management can beof as high performance in a refurbished buildingas in a newbuild.

However, there may be individual cases wherethe inherent qualities of a building present insur-mountable problems.For example,buildings withvery deep plans, relying entirely on air-condi-tioning and artificial lighting, built in an era ofcheap energy (Figure 1.5), will always be prob-lematic both for their energy consumption, andinternal environmental quality.Thus it is impor-tant to properly assess the potential forrefurbishment, before conclusions are drawn.

1.4 Implications for change of use

Refurbishment is often accompanied by changeof use.This may be across recognized use types for example a nursing area of a hospital becom-ing an administrative centre (Figure 1.6), or achange from residential to office use (Figure 1.7).Or it may be that within a use type the func-tional demands on spaces are changing due toreorganization and the impact of changes inpractice and technology. For example, develop-ments in IT have a continuing influence onoffice practice and the spaces that support it.

Figure 1.6 REVIVAL building Meyer Hospital, Florence:Refurbishment accompanies change of use from nursingarea to hospital administrative and reception area, involvingdifferent environmental conditions

Strategy for Low Emission Refurbishment 5

Figure 1.4 The annual CO2 emissions per m2 for 92 officebuildings in the UK. The 20-fold variance illustrates theinteractive effect between building, services and occupants

Source: Data from Energy Consumption Guide 19 Energy Efficiency inOffices (1998) BRECSU,Watford

Figure 1.5 Deep-plan buildings such as these, built in theera of cheap energy and relying on air-conditioning andartificial lighting, may present insurmountable problems forsustainable refurbishment


Figure 1.7 REVIVAL building The Albatros, Den Helder, TheNetherlands: Refurbished in conjunction with change of usefrom residential to offices

It is difficult to generalize here, but it could besaid that opportunities are sometimes missed be-cause designers impose stereotypical solutions,often ignoring the serendipity of fitting a newfunction into a building generated by a differentset of aims.

For example, in a conversion of an old fac-tory workshop to modern office use, highceilings with exposed structural slabs are oftenreplaced with suspended ceilings for acousticreasons, and under the misguided impression thatthe original spaces would be impossible to heatefficiently.This action not only destroys much ofthe architectural quality of the space,but will alsohave a negative influence on daylight distribu-tion, natural ventilation and, possibly, thermalresponse.

Change of use may bring about changes inpurely technical parameters.These include:

occupancy pattern and density; internal gains; lighting levels; ventilation rates; thermal set-points and response; acoustic properties (reverberation time,noise

exclusion).

These changes may bring about benefits and dis-benefits. For example, an historic warehouseconverted into a library will create a difficultchallenge to the designer if the intention is toprovide daylight, due to the shallow floor-to-ceiling height.On the other hand, a heavyweightbuilding that required wasteful intermittent heat-ing in its original function as a primary school,would not be so inefficient if used for a muchlonger occupied period as, for example, a healthclinic. Furthermore, the intermittent heatingwould be less wasteful anyway if the envelopeinsulation was improved as part of the refurbish-ment package.

Thus, the inherent properties of the building,the operational requirements of the new use, andthe technical options in the refurbishment allhave to be considered interactively.

Impact on energy consumption

In spite of improvements to the performance ofthe fabric and systems, change of use may bringabout an increase in the energy consumption.This does not necessarily mean that the low-energy refurbishment has failed, since the meas-ures adopted have undoubtedly led to lowerenergy consumption than if absent.

In measuring the success of the refurbishmentthen, it would be fair to make a comparison ofthe buildings actual energy performance (shownatA in Figure 1.8) with, firstly, the existing build-ing under the new use and complying withaccepted comfort conditions, but without adopt-ing low-energy measures (B). Secondly, acomparison should be made with a new build-ing of similar use type (C).We might expect aperformance somewhere between these two orwith really successful refurbishments, even sur-passing typical newbuild performance. Finally, acomparison should be made with the averageemissions for the building stock of the same usetype (D).

The example here shows that the refurbishedbuilding emits 35 per cent of that predicted forthe original building with a change of use, and

6 Principles


58 per cent of that of the measured average forthe existing building stock, although it emits 10per cent more than a new building.The fact thatthe refurbished building with its new use emitsnearly twice that of the original building withits original use, is not of much relevance.

Figure 1.8 Comparing like with like: Assessing theimproved performance of a refurbished building

1.5 Environmental comfort standards

Improved comfort standards are often the initialmotivation for refurbishment. The buildingshown in Figure 1.9, an office block built in the1970s, is poorly insulated with large areas of sin-gle tinted glazing, no shading and a poorlycontrolled heating system. Since its original oc-cupation, density has increased, and there hasbeen a proliferation of computers and otherbusiness machines. The frequent complaint isoverheating in summer, both under-heating andoverheating in winter, and poor air quality.

The clients presumption may well be that fullair-conditioning would be the answer. If con-ventional comfort standards were sought, thiscould indeed true, although this would be nei-ther an economical nor environmentally friendlysolution.

If refurbishment measures included shading,improving the envelope insulation, and reinstat-ing openable windows, comfort conditionswould be greatly improved, although the strict

standards achievable by air-conditioning may stillnot be met for all of the year.However, it is nowwidely accepted that for buildings running underpredominantly passive systems, occupant satis-faction can be high, even when the conventionalstandards are not met.

A key factor is the presence of adaptive oppor-tunity.This is the ability of the occupant to makechanges to the environment, and/or makechanges to their personal condition, in order toimprove their comfort.Typical opportunities thatmight be present are listed below.

Positive adaptive attributes relaxed dress code; occupant mobility; access to hot/cold drinks; openable windows; adjustable blinds; desk fan or locally controlled ceiling fan; local heating/cooling controls; workstation/furniture flexibility; shallow plan (minimizing distance from win-

dows); cellular rooms (reduces mutual disturbance); surface finishes appropriate to visual task;


A

B

C

D

E

refurb. building, new use.ACTUAL

original building, new use.CALCULATED

newbuild, new use.CALCULATED

average for building stock of same use type. ACTUAL

original. building, old use.ACTUAL

energy consumption

Figure 1.9 An over-glazed lightweight building of the1970s suffering from overheating in summer and under-heating in winter. The clients perception is often that theonly solution to comfort problems is air-conditioning


daylight and task lighting backup; good views (external and internal); transitional spaces (verandahs, atria, etc.); good access to outside areas.

Negative adaptive attributes uniformity of physical environment (temper-

ature, lighting, colour); deep plan, reduced access to perimeter; dense occupation with restricted workstation

options; sealed windows; views obstructed by fixed shading devices; central mechanical services control.

Studies have shown (Baker and Standeven, 1994)that the presence of several of the positive at-tributes will result in occupants toleratingtemperature excursions typically up to 5Cabove conventional upper temperature limits,and around 3C below conventional lower lim-its. This may allow the designer to opt for thepassive solution rather than the air-conditionedsolution.

This will have implications for initial cost,maintenance cost and carbon emissions. It willalso have implications for the choice and prior-itizing of refurbishment measures. For example,if it were decided to air-condition the building,the replacement of standard double glazing withhigh performance low-e units would have agreater impact on carbon emissions than if thebuilding were to be freely ventilated by open-able windows.This is because the temperaturedifferential in the latter case would be small oreven non-existent. However in both cases, shad-ing would be highly beneficial.

In some cases, exceptional overheating con-ditions may be unacceptable, althoughconditions prevailing for most of the year maybe satisfactory without air-conditioning. In thiscase, intermittent comfort cooling may be ap-plied. The technological aspects of this arediscussed in section 7.11. Here we make thepoint that a modest dependence on comfortcooling may result in a building being able to

take the predominantly passive option. Further-more, because of the intermittent nature of thecomfort cooling, and its controllability, it will notbe necessary to apply such strict comfort limitsas in a conventional air-conditioned building.This strategy, often referred to as hybrid ormixed mode, results in comfort cooling oftenbeing a viable and energy efficient option.

1.6 Passive environmental strategies

Statistically, air-conditioned buildings consumesignificantly more energy than naturally venti-lated buildings. In temperate climates, fieldstudies have shown that in spite of the extra cap-ital and running costs, occupant satisfaction wasno greater than in naturally ventilated buildings(Figure 1.10). Even in hotter climates, as a studyof office buildings in Lisbon showed, satisfactionin some air-conditioned buildings may be sig-nificantly less than in some naturally ventilatedbuildings.Thus the strategy for avoiding air-con-ditioning is a good one, although hybrid systemsand comfort cooling (described later in section7.11) may represent a viable alternative.

The situation often faced in refurbishment isof a building with very poor comfort conditions,where air-conditioning is seen as the only solu-tion. However, it could be that after makingfabric and system improvements, comfort con-ditions become acceptable.This should be testedby analysis or simulation before the air-condi-tioning option is adopted.

This may even apply to a building that has air-conditioning already.Many over-glazed buildingsof the 1960s and 1970s were subsequently air-conditioned to make conditions bearable.However, measures such as shading, fabric insu-lation, reduction of glazing area, adoption ofadaptive controls, may well render full air-con-ditioning unnecessary. Even if air-conditioningis adopted, these measures will reduce the air-conditioning loads significantly.

8 Principles


Natural ventilation

Many candidate buildings for refurbishment willhave high rates of infiltration.This is particularlytrue of buildings constructed using pre-cast con-crete components, and panel and curtain wallsystems, with dry linings typical constructiontechniques of the 1960s to 1980s era (Figure1.11). In buildings with original glazing systems,these too were very leaky. In cooler climates, theresult of the high infiltration rate is a waste ofenergy due to heat loss.However, one benefit ofthe high air-change rate was good air quality.

Figure 1.11 REVIVAL building Lyce Chevrollier, Angers,France: Built in 1958 of pre-cast concrete construction withdry lining and poorly fitting metal windows, it had very highinfiltration rates before refurbishment

Refurbishment measures to reduce uncontrolledinfiltration must then recognize the need to pro-vide ventilation to ensure that a minimum airquality is maintained.This does not mean thatthe benefits of the more airtight envelope willall be lost, provided some means to prevent over-ventilation is present. Broadly, the principle isbuild tight, ventilate right.

In predominantly warm climates (i.e.with lit-tle winter heating) reduction of infiltration onlybrings energy benefits if the building is air-con-ditioned to a temperature significantly below theprevailing outdoor temperature. If it is not to beair-conditioned the main concern switches togetting enough ventilation to remove heat gainsand to generate air movement.This will demandlarge openable areas.

Night ventilationA further important function may be the provi-sion of night ventilation to cool the structuralmass.The principle is illustrated in Figure 1.12.This function will also require large openableareas in the envelope, and unobstructed flowpaths within the building. Furthermore, it is es-sential that the ventilating air can be thermallycoupled with the thermal mass of the building.These requirements may present design chal-lenges, particularly in relation to security andnoise control.


Figure 1.10 Overall occupant comfort byventilation types; natural ventilation (NV),advanced natural ventilation (ANV), mixedmode (MM) and air-conditioned (AC). Thecoloured plots are for the PROBE (UK) surveyand the open plots from the Building UseStudies data. Summer survey results from 26office buildings in Lisbon show that occupantsatisfaction in naturally ventilated buildings(NV) and partially air-conditioned buildings(PAC) was higher than in air-conditionedbuildings (AC)

Source: The Probe Study (2001) Building Research andInformation, vol 29, 2 March


Daylighting

For the two or more centuries since the indus-trial revolution, when man moved indoors,daylight had been too valuable an asset to waste.Architects responded by a whole typology ofwindow and rooflight designs, readily acceptingthe need for shallow plans, light wells and court-yards (Figures 1.13, 1.14). This constraint wasreinforced by the same need for shallow plan toachieve good natural ventilation. Whilst, ofcourse, artificial light had to be employed afterthe hours of darkness, daylight was always thepreferred source in the daytime, and artificiallight was regarded as inferior both technicallyand on health grounds. The latter dated frompre-electric times when oil and gas lighting cre-ated serious levels of indoor pollution and firerisk.The development in the 1950s of the fluorescentlamp, together with relatively cheap electric en-ergy, prompted designers to question the needto provide the working illumination by daylight(Figure 1.15).This freed them to adopt deeperplans, which in principle made economies inspace efficiency and building cost.

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acousticvents

G

1

2

minimum ventilation

17C

maximum ventilation

23C 23C 27C

Figure 1.13 Wauquez Department Store (now a museumof cartoon art), Brussels: Rooflighting the top floor (1920).The architect Horta could not resist architectural elaboration

Figure 1.12 The principle of nightventilation: The mass of thebuilding is cooled at night toprovide a heat sink for internalgains during the day


Buildings of the 1960s to 1980s found them-selves at a crossroads.On the one hand glass andglass-supporting cladding technology had madegreat strides to support the modernist,minimal-ist view of facade design, often with huge areasof glazing (Figure 1.16).On the other hand, theimprovement by a factor of five in the luminousefficacy (lumens light output perWatt electricalinput) of the fluorescent lamp over the incan-descent lamp meant that it was now technicallyand economically feasible to provide the work-ing illumination entirely artificially.The result of these conflicting influences meantthat the art of good daylight design was virtuallylost. Initially the over-glazed buildings were, notsurprisingly, over-illuminated leading to glare,overheating in summer due to solar gain, andsuffering from large heat losses in winter. Re-sponse to these included, ironically, permanentsupplementary artificial lighting (PSALi) where

the poor light distribution due to large areas ofside-lighting was balanced by artificial lightingaway from the perimeter zones. The next re-sponse was to reduce the light transmittance ofthe windows to values as low as 25 per cent,withtinted and reflective glass (Figure 1.17). Finallythe contribution of daylight was abandoned al-together. This allowed a retreat into deep plan,and for a brief period a knee-jerk response ofdrastically reducing glazing areas.The resultingdeep plan, air-conditioned, artificially lit build-ings from this era have proved to be the highestenergy users and the most likely candidates forsick building syndrome (SBS) (Figure 1.18).

Within our target building group all of thesetypes will be found.The followingTable 1.1 pro-vides a response strategy.

Finally, the benefits of daylighting and goodwindow design extend beyond the saving of en-ergy. There is growing evidence that the view


Figure 1.14 County Hall, London, 1908: Even large buildings were in fact shallow plan, providing access to daylight and naturalventilation


from windows and the perception of the pres-ence of daylight, even without direct views, isvalued by occupants.This can lead to increasedwell-being and productivity, and also increasedtolerance of non-neutral environmental condi-tions. The latter offers significant support to theadoption of a passive strategy.

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Figure 1.16 The transparent building huge areas ofglazing and shallow plan: Delft University, circa 1960

Figure 1.15 The leap forward in luminous efficacy of thefluorescent lamp heralded the daylight dark ages. Deep-planbuildings abandoned daylight and natural ventilation, andwindows were relegated to providing occasional views

Figure 1.17 First efforts to overcome the effect of largeareas was to reduce the transmission of glass by reflectiveand absorptive glasses

Figure 1.18 The Kalamazoo building, Birmingham,completely abandoned daylight with deep plan, slitwindows and full air-conditioning. Buildings of this type areprime candidates for sick building syndrome. It wasdemolished in 2003.


1.7 Prioritizing refurbishment options

Most building projects, whether refurbishmentor newbuild, are ultimately budget limited.Budgets will constrain both sustainability meas-ures and functional design solutions. In theformer case, a typical example might be the in-stallation of a photovoltaic array technicallypossible to meet the equivalent electrical load ofthe building (we will call this environmental bene-fit), but prevented by prohibitive cost. In thesecond example, a more generous budget for fur-nishings would be regarded as desirable but notviable (we will call this personal benefit). In somecases, budget constraints may interact with deci-sions which affect both of these areas forexample, limiting the space provision per occu-pant will probably be seen as a reduction inquality from the occupants point of view, butmay well improve the energy use per occupant.In other cases, a measure may create benefits inboth categories for example, improving access

to daylight will reduce energy consumption andbe seen as a positive move by most occupants.

The interaction of types of benefit (i.e. envir-onmental or personal) and the sometimesconflicting, sometimes mutually supporting,out-comes, makes the prioritizing of refurbishmentmeasures difficult. Consider the case where twomeasures insulating the roof or installing shad-ing devices are of similar cost, but havedifferent levels of impact on the occupants.Roofinsulation will bring economic benefit to thebuilding operator, environmental benefit due toreduced heating load, but no personal benefits.On the other hand, shading devices will improvepersonal comfort conditions, may improve theappearance of the building, and if the building isto be air-conditioned,may reduce cooling loads.

How do we resolve this question?We suggestthat the environmental benefits and personalbenefits have to be treated separately, initially.When there is a clear quantitative ranking of en-vironmental measures, then personal benefits


Table 1.1 Daylighting strategies for refurbishment

Building type Daylight status Refurbishment strategy

Shallow plan, small glazing area Daylighting provision degraded.1 Reinstate daylighting, install photo-responsivecontrols.

Shallow plan, large glazing area Daylighting degraded by low Consider reduction of glazing area, hightransmissivity glass or fixed shading, performance daylighting2 (adjustable shading andor nothing. high performance glass). Install photo-responsive

controls.

Deep plan, large glazing area Daylighting abandoned even in As above for perimeter zone. Consider advancedperimeter zone, as above. High daylight options to increase daylight penetration.levels of uniform artificial light. Install rooflights (top floor) and consider light

wells. Install task lighting with low illuminancephoto-responsive background lighting.

Deep plan, small glazing area Daylight abandoned. High levels Consider increasing glazing area together withof uniform artificial lighting. measures above.

1 Daylighting performance may be degraded by inappropriate shading design, internal or external obstructions, poor distribution due to lowered ceilings and lowreflectance surfaces, deliberate reduction of transmission of glass by films or paintwork.

2 The term high performance daylighting refers to the technical means to balance the usefulness of daylight to perform the visual task, and the positive benefits ofview, with the disbenefits of overheating and glare (see High performance daylighting Appendix).


should be considered. This is not because thepersonal benefits are any less important, but be-cause they are far less easy to quantify.There maybe cases, however, where the personal benefitsare the primary concern, or may even be essen-tial for example, the replacement of asbestoswith a non-toxic insulant.

Table 1.2 below is indicative only.All of thebenefits are dependent on circumstances forinstance, the impact of improving plant efficiencyobviously depends on the existing efficiency andthe final efficiency.

Quantifying energy benefits

Here we review typical refurbishment optionsand apply them to a range of scenarios. Ofcourse it is not possible to create global rankingof measures since their performance is very sen-sitive to the context. For example, improvingenvelope insulation to a building in a cold cli-

mate will have far greater benefit than in a mildclimate, whereas the case for shading devicesmight be reversed. Similarly the building typewill influence priorities a shallow-plan schoolbuilding occupied predominantly in the day willbenefit far more from the investment of im-proved daylight access than an institutionalbuilding occupied for 18 hours per day.Thereare too many combinations of parameters to at-tempt comprehensiveness; rather, this example isgiven as an illustration of the interaction ofmeasures and the strong impact on priority.

To assess these scenarios we have used the LTEurope software.This software developed fromthe LT Method takes account of the interactionbetween lighting heat gains, solar gains, occupantgains and losses through the envelope elementsand ventilation. It evaluates energy inputs forheating, lighting, ventilation and cooling, and canindicate comfort levels resulting from the omis-sion of mechanical cooling. It can also evaluate

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Table 1.2 Environmental and personal benefits of refurbishment measures

Technical measure Potential environmental benefit Potential personal benefit

Change fuel type large zero

Improve plant efficiency large zero

Improve controls large moderate

Insulate envelope large zero to small

Improve daylight access moderate moderate

Install shading moderate moderate to large

Install task lighting moderate large

Increase occupant density moderate -ve small

Improve noise control zero large

Improve art. light spectral qual. -ve small small

Reduce occupant density -ve moderate moderate to large

Provide comfort cooling -ve moderate large

Note: Environment refers to global environment.


the impact of thermal mass and the benefit ofnight ventilation

The software computes the energy in primaryenergy units, which closely relate to CO2 emis-sions.The cooling loads are calculated on a 25C

set-point. In the naturally ventilatedcase, overheating is defined as thenumber of days with two consecutivehours or more above 27C.

The example studied here is a typ-ical 1970s medium-sized four-storeyoffice block with a 14m 34m foot-print. It is set in an open site in theUK, where there is both a significantheating and cooling load.The build-ing is glazed on both long facades thatface north and south,with single glaz-ing occupying 70 per cent of thefacade area.The envelope is leaky andpoorly insulated (U-values around1.5).Due to lack of solar controls, andinternal gains due to low efficiencylighting and fast growing IT installa-tions, frequent overheating hasprompted the installation of air-con-ditioning, together with tintedwindow film. Controls are poor, andthe centrally switched lighting is on allday. Occupant satisfaction is very low,energy costs high, and it is now in direneed of refurbishment.

Figure 1.19 shows the case com-parison, displaying the total primaryenergy consumption for the base casedescribed above (labelled case 1) fol-lowed by the application of 11measures aimed at improving energyperformance. This shows firstly how

the measures interact, and secondly providessome evidence as to how their cost effectivenesscould be ranked, although the cost of the meas-ures is not given explicitly.


Figure 1.19 Case comparison from the LTEurope software showing the progressiveimprovement in energy and overheatingperformance for natural ventilation and air-conditioning


The cases explored are as follows:

Case 1 base caseCase 2 base case + low-e glazingCase 3 base case + boiler efficiency

increased from 65 per cent to 85 percent

Case 4 base case + high efficiency lightingCase 5 (4) + vent rate reduced 1.5ac/h to

1.0ac/h, boiler efficiency increasedfrom 65 per cent to 85 per cent

Case 6 (5) + photoelectric lighting controlsCase 7 (6) + low-e glazingCase 8 (7) + insulated opaque envelopeCase 9 (8) + reduced glazing areaCase 10 (9) + summer high ventCase 11 (10) + night ventilationCase 12 (11) + high thermal mass

Case 1. The building starts with high heating,lighting and cooling loads.Without air-condi-tioning, overheating is around 45 days per year,about ten times an acceptable level. Clearly theair-conditioning was essential.

Case 2. Here the envelope is identified as hav-ing poor thermal performance and it is proposedto reglaze with low-e double glazing.This is anexpensive option and the results are disappoint-ing with only a 10 per cent reduction in energy.

Case 3. This shows a much cheaper option ofincreasing the boiler efficiency from 0.65 to 0.85per cent which shows a saving of 8 per cent. Inreality, this may reduce emissions further due toimproved combustion. It will also cause muchless disturbance to the use of the building.

Case 4.This returns to the single glazing to con-centrate on the other large component, lighting.The existing lighting situation is bad, with poorefficiency lamps and luminaires only delivering20 useful lumens per watt (l/w)1 with a designluminance of 300 lux. This can easily be im-

proved to 40l/w and the design luminance re-duced to 200 lux, made possible due to thewidespread use of self luminous computerscreens, and task lighting where necessary.Thishalves the lighting energy. But there is a penaltyto pay in heating, and about half of the decreaseof energy is lost. However the net effect for theair-con case is a reduction of 21 per cent, and 30per cent for the naturally ventilated case, and isthus, together with the increased boiler effi-ciency, certain to be far more cost effective thanthe low-e glazing. Note too, that there is a sig-nificant reduction in overheating days,which hadactually increased with the low-e glazing.How-ever, overheating days are still around 28,whichis unacceptable.

Case 5. The increase in heating load promptstwo measures to improve the thermal perform-ance. One is to improve the airtightness of theenvelope, reducing the infiltration from 1.5 to1.0 air changes per hour (ac/h), which mayprove to be a technical challenge, and secondly toimprove the heating plant further to an efficiencyof 0.9, achievable with a condensing boiler.Thislargely compensates for the loss of heat gainsfrom the lighting.

Case 6. Lighting energy is reduced further bythe installation of photo-sensitive controls. Ascan be expected for a shallow-plan building with(more than) adequate glazing area, a large savingis made, reducing the lighting energy to about35 per cent of the uncontrolled value. It is worthnoting, that if this had been applied before theefficiency of the lighting had been improved, theabsolute savings for this measure, and thus its costeffectiveness, would be even greater. In this casethe reduction in lighting energy has only led toan increase in heating energy of about 10 percent, and this is probably because the lights aregoing off in the middle part of the day,when formost of the year net heating loads are very small.However, together with case 4 it does demon-

16 Principles

1 This includes the lamp efficacy and the utilization factor of the luminaire and room combination.


strate the dependence of heating loads on casualgains.

Overheating has steadily reduced, down to 20days, and there is now a real possibility of aban-doning air-conditioning.So from now on,we willconcentrate on the natural ventilation option.

Cases 7 and 8.We now return to test the effectsof improvements to the envelope, and in case 7low-e glazing is installed again.This results in a40 per cent (of case 6) reduction in the heatingload. When combined with insulation to thewalls and roof (case 8) the reduction in heatingload is 64 per cent (of case 6).This is of course avery expensive measure, and still could be of rel-atively poor cost effectiveness. However, if therewas already a need for fabric improvements dueto failure in weathering function, much of thiscost would be offset.

Case 9. In case 9 the glazing area is reducedfrom 70 to 35 per cent on both south and northfacades.This has little effect on energy balance there is only a small increase in lighting energy,and the reduction of heat loss from the north fa-cade is compensated by a loss of useful heat gainson the south facade. However, this strategy car-ries two important advantages. Firstly it reducesunwanted solar gains, significantly reducing over-heating; secondly, it reduces the cost of low-eglazing; and thirdly, if expensive shading treat-ment is necessary, it will be needed on a muchsmaller area. It should be noted that the reduc-tion would have had a much bigger impact onheat loads had the glazing not already been up-graded to low-e.

Case 10. However, the improved thermal per-formance of the envelope has had a downsidewith a disappointing increase in overheating dueto the reduced heat losses (case 8), only partiallycompensated by the reduced glazing area. Howdo we increase heat losses on demand? By open-ing windows.When air-conditioning had beeninstalled, the windows were sealed.By reinstatingopenable windows, high air-change rates are

possible in summer, and overheating can be fur-ther reduced as in case 10.

Case 11. But overheating is still around 14 daysper year.Night ventilation is known to be effec-tive in cooling the structure at night with thecooler night air, and preparing the thermal massto absorb gains made in the daytime. Case 11with night ventilation shows a significant reduc-tion to seven days.

Case 12. Here an attempt to make further im-provements is tested, where during the fit-out,structural mass is exposed by removing suspendedceilings and carpeted floors.This reduces over-heating to four days, but at the expense of someextra heating due to intermittent occupation.

ConclusionsThe series of cases shows the interaction be-tween measures and their varying impact.Although generic costs are not provided expli-citly, it is quite clear that the measures will varywidely in cost effectiveness, and this should beborne in mind when establishing the priority ofupgrading measures.

It also demonstrates that a critical point intemperate climates is the ability to move fromair-conditioning to natural ventilation. This ispartly because air-conditioning carries a largeoverhead of fan and pump energy, which is notdirectly proportionate to the cooling (or heat-ing) load.The result, in this case, of moving fromthe air-conditioned base case, to the naturallyventilated final case is a reduction in primary en-ergy consumption of 81 per cent. It must bepointed out, however, that improvements couldhave been made in the efficiency of the air-con-ditioning system that are not tested here, andwhich would have reduced the final difference.

Although some of the discussion has referredto percentage changes, in order to indicate im-pact, ultimately it is the absolute reduction ofenergy or CO2 emissions against which a meas-ure should be judged. Thus a further largepercentage reduction to a load that has already



been reduced to a small value, isless cost effective.This implies thatthe order that measures are appliedis important.

Climate will affect the relativeimpact of measures. In warmer andsunnier climates, insulation willhave less impact in the naturallyventilated case, and measures to re-duce overheating more. Similarly,building type will influence therelative impact of measures. Abuilding such as a junior schooloccupied for the middle part of theday will benefit more from im-provements to daylighting than, say,a hospital, occupied for 24 hoursper day,whereas in the case of thermal improve-ments to the fabric, the reverse may be true.

1.8 Integration with newbuild

Refurbishment projects often include varyingdegrees of newbuild (Figure 1.20).This couldrange from a small wing or extension, to majorseparate blocks totalling a built surface as greator greater than the original building. In somecases this may involve demolition and replace-ment, and in others, the newbuild may simplybe intensifying the site coverage.

We can identify two broad categories of integra-tion that could affect environmental performance.

1 architectural2 engineering.

Architectural integration includes consideration forthe massing of the final building as well as theaesthetic and stylistic qualities of both old andnew.Only the former issue is dealt with here.

The massing of a complex building or groupof buildings can have a significant effect on theavailability of daylight, the penetration of sun-light and the microclimate of spaces around andenclosed by the buildings. For example, on a visitin spring to the Lyce Chevrollier building, itwas observed that the classrooms in block F hadlights on, whilst most in block E were off.Thisclearly is a result of the obstruction of the newblock C (Figure 1.21).This new block will alsoaffect availability of lower angle sun, and thusmay reduce existing overheating problems, andhence the need for shading.

18 Principles

Figure 1.20 The new wing and atrium built as part of theLyce Chevrollier (Angers, France) refurbishment. The oldwing is on the right behind the retrofit shading

Figure 1.21 Plan of Lyce Chevrollier showing the newblock N which caused some obstruction to daylightavailable in the original block H


This illustrates the need to give full consider-ation to the environmental impacts of the newmassing and interaction of all parts of the pro-ject.Another REVIVAL example is shown in theMeyer Hospital Case Study (Chapter 12) wherethe addition of a new greenhouse on the southelevation affected the daylighting of the adja-cent office rooms in the original building.Engineering integration is concerned mainly

with the integration of services. In particular,heating plant may serve all parts of the project,and according to the amount of increase of builtsurface area, the plant capacity may have to beadjusted.On the other hand it could be that ex-isting plant will be adequate for an increasedbuilt area due to the savings made by the im-provement to the existing refurbished part. Inany event, unless the heating plant has been re-newed recently, and the distribution mains are ofa good standard,new plant, properly sized for thetotal development, is likely to be cost effective.

One further consideration,where the projectis an extensive building complex, is that distrib-uted plant may be the best option.This is becausedistribution mains for heating and cooling arecostly in capital,maintenance and running costs,and with modern IT control and building en-ergy management systems, personal physicalpresence to control plant in a central location isfar less necessary than it used to be.

1.9 Eco-communities and urban renewal

This is a planning concept concerning commu-nity-scale policy and design rather thanindividual buildings. The term covers a wide

range of principles, from near-spiritual attitudesabout living with nature, to more pragmatic is-sues such as waste recycling and low carbontransport systems.

The prefix eco (from the Greek echos home),is rather widely used, but refers here to the con-cept of interdependence of buildings, the activitieswithin them,and their occupants, in some syner-gistic way, that also supports sustainability andminimizes negative impacts on the wider envir-onment. It is essentially opportunistic just as inecology, in the conventional biological sense,we seedifferent organisms occupying niches in a con-tinuous cycle of energy and material, so too in thismore human-dominated context we see activitiesand land use having a similar interdependence lo-cally, and thereby reducing global dependence.

There are three reasons why it is of relevancein refurbishment projects. Firstly, the project maybe quite extensive particularly if it includeshousing where many units may be refurbishedby the same principles. Clearly there are oppor-tunities here to consider the area as a whole,howit interacts within itself and how it interacts withits immediate surroundings.

Secondly, some building types naturally inter-act with their surroundings both socially andphysically. For example, a refurbished factory willneed a workforce which in turn will requiretransport and/or accommodation. It may alsoproduce low-grade heat as a by-product, whichcould be used for space heating via a districtheating system.

Finally, it is particularly relevant in urban re-newal areas,where the refurbishment may covergroups of buildings of differing use types, as well


Figure 1.22Eco-community renewalscheme at New Islington, UK


as infrastructure, and changes of land use (Figure1.22).

In the example above, this will have implica-tions for decisions made in the refurbishment ofboth the housing and the factory, at a strategicand detailed technical design level.At a strategiclevel, the decision to use waste heat has a polit-ical aspect, since it will affect the cost both inmoney terms and carbon emissions, and will re-quire management, and should bring benefit toboth the user and the producer. At a technicallevel the use of waste heat rather than individualheat sources may require heat emitters that canfunction at low water temperatures, and exter-nally will require consideration for the routingof the heating mains.

To the left is a table of the most likely possi-bilities for eco-interaction in relation torefurbishment projects.Most are concerned withenergy production,but some are concerned withenergy and resource conservation.

1.10 Environmental regulation

Building refurbishment is increasingly beingbrought under mandatory control in Europe andthis is a trend that is likely to continue. TheEuropean Commission is driving forward vari-ous initiatives with which individual MemberStates must comply but also individual countriesare introducing further requirements for bothnew and existing buildings.

Energy Performance of Buildings Directive

DIRECTIVE 2002/91/EC OFTHEEUROPEAN PARLIAMENTAND OFTHE COUNCIL of 16 December 2002 on theenergy performance of buildingsThe Energy Performance of Buildings Directive(EPBD) is the European driver for improvingthe energy performance of all buildings in allEuropean countries. Each country is required totranslate the Directive into national legislationaccording to an agreed timetable.

20 Principles

Table 1.3 Potential for eco-interaction in large scalerenewal projects

ENERGY SUPPLY

Heat Group solar thermalWaste industrial heatHeat from sewage and waste waterHeat from waste incinerationCombined heat and powerGroup solar thermalWaste high-grade biomassBiomass production from cropsAmbient sourcesGeothermal (and cool)Marine (and cool)

Electricity Combined heat and powerShared wind powerShared solar thermal with storageShared PV arraysHydro powerTidal power

ENERGY CONSERVATION AND COMFORT

Microclimate Wind sheltering with vegetationWind sheltering by buildingsWind access in summerSolar shading with vegetationSolar shading by buildingsSolar access in winter

Building specification MaintenanceTechnical support

Outdoor amenity space MicroclimateAccessibilityAdaptive opportunityPrivacySecurityManagementGardens and food production

Transport Access to public transport networkCycle pathsCycle storage and securityFootwaysCar parking and accessTransport sharing schemesTraffic management hierarchy

Water and sewage Rain water catchmentGreywater managementReedbed purification

Waste disposal and recyclingWaste sortingCompostRe-use


The EPBD is designed to provide informa-tion on the energy performance of a building toprospective buyers and tenants, or in the case ofpublic buildings, the information is to be dis-played inside the building to inform all visitors.The objective is to raise awareness of the energyuse of buildings, allowing prospective buyers andtenants to make informed decisions, and en-couraging building owners and occupiers toimprove the energy performance of new and ex-isting buildings.

The main components of the EPBD relevantto existing buildings are given in the two boxesbelow.

Article 6: Existing buildings

Member States shall take the necessary measuresto ensure that when buildings with a total usefulfloor area over 1000m2 undergo major renovation,their energy performance is upgraded in order tomeet minimum requirements in so far as this istechnically, functionally and economically feasible.

Article 7: Energy performance certificate

1. Member States shall ensure that, when build-ings are constructed, sold or rented out, anenergy performance certificate is made avail-able to the owner or by the owner to theprospective buyer or tenant, as the case mightbe.

2. Member States shall take measures to ensurethat for buildings with a total useful floor areaover 1000m2 occupied by public authorities andby institutions providing public services to alarge number of persons and therefore fre-quently visited by these persons an energycertificate, not older than 10 years, is placed ina prominent place clearly visible to the public.

Implementation:The example of UKArticle 6 of the EPBD is translated into UKlegislation via Building Regulations.

Building refurbishments that accompany achange in use are subject to energy use, andother provisions, of planning and Building Reg-ulations control. Replacements to buildingenvelope components, including windows, ven-tilation equipment and mechanical and electricalservices, must comply with the Building Regu-lations 2000. Additionally, building energyperformance must be improved when major re-furbishments are conducted for buildings over1000m2. Energy requirements for building ex-tensions and the commissioning of services arealso included in Building Regulations. Large-scale refurbishments, or those that lead to achange in use of the building, may result in theproject being considered equivalent to a new-build.

The energy efficiency provisions of BuildingRegulations will continue to be used by gov-ernment to drive improvements in the existingbuilding stock; it is the intention that forthcom-ing updates planned for 2010 and 2013 willfurther strengthen the energy performance re-quirements of refurbished buildings.

Article 7 of the EPBD requirements have beentransposed into British legislation and are com-ing into force in England and Wales between2006 and 2011. Legislation will be coming intoforce in Scotland and Northern Ireland over asimilar period.

Energy Performance Certificates (EPCs) arebased on the Asset Rating (a calculated annualenergy consumption based on a standard use ofthe building). EPCs provide the buildings rela-tive energy efficiency in a similar form todomestic product energy ratings, and must beprovided to prospective buyers or tenants whena building is constructed, sold or rented.



Display Energy Certificates (DECs) are basedon the Operational Rating, that is the measuredannual energy consumption of the building.DECs are required for buildings over 1000m2

occupied by public authorities or other institu-tions that provide public services to a largenumber of people, from October 2008. DECsmust be prominently displayed in the building toinform visitors.The government has committedto consult on the possible widening of these re-quirements to privately owned or occupiedpublic buildings including retail outlets, cinemasand hotels. EPCs and DECs are produced by ac-credited energy assessors and are accompaniedby a report detailing voluntary options for im-proving the energy efficiency of the building.

Using other legislation in the UK

There has been a clear trend for at least the lastdecade to reduce energy consumption in the ex-isting building stock,with Building Regulations,planning policies and requirements regarding theprovision of information to stakeholders all pro-gressively strengthening.

Planning policies. Local planning policies sup-ported by government legislation and RegionalPlanning increasingly require developments touse local heating networks (where available)and/or to use renewable energy sources (on,nearor off site) to supply a proportion of their energyrequirements.Exact local planning requirementsregarding building refurbishments can differ sig-nificantly between local authority areas. As such,local planning requirements should always beconsulted prior to any refurbishment.

Carbon Reduction Commitment.The Car-bon Reduction Commitment (CRC) is a newscheme, announced in the EnergyWhite Paper2007, which will apply mandatory emissionstrading to cut carbon emissions from large com-mercial and public sector organizations (includingsupermarkets, hotel chains, government depart-ments, large local authority buildings), with

carbon reductions of 1.1 Megatonnes of carbonper year expected by 2020.The Department forEnvironment, Food and Rural Affairs (DEFRA)is currently determining how the CRC will op-erate, with implementation expected in January2010.

Voluntary schemes and drivers

Various voluntary standards have also been de-veloped for reducing energy use in existingbuildings; such standards are often a precursor tofurther mandatory controls.Voluntary schemesmay be strong drivers for refurbishing buildingsto low carbon standards, and are used by someorganizations to impose standards on buildingsthey occupy. In the UK BREEAM (BuildingResearch Establishment Environmental Assess-ment Method) has for many years been acceptedby industry as a general standard for assessing theenvironmental sustainability of non-domesticbuildings, has been an important driver for theimprovement of the building stock and has beenwidely used for promotional purposes.Many or-ganizations have environmental policies andregularly report on their Corporate Social Re-sponsibility (CSR).Carbon emissions form a keyelement of this, with energy efficiency creden-tials often highlighted as an indicator of aresponsible approach in the community. Year onyear improvements in reducing carbon emissionsare usually a component of this reporting, withupgrading existing building stock a common ac-tion item.

The UK Energy Efficiency AccreditationScheme (EEAS) is the leading independentemission reduction award scheme in the UK andis open for both commercial and public sectororganizations.The Scheme provides advice forimproving energy efficiency and requiresdemonstrated improvement in energy perform-ance to secure accreditation. By gaining andmaintaining accreditation,organizations involvedin the Scheme are able to raise the profile of de-livered energy and carbon reductions bothinternally and externally, and can benefit from

22 Principles


ongoing support to deliver further emission re-ductions through membership of theAccreditedOrganizations Network.

References

Baker,N. and Standeven,M. (1994) Thermal comfort infree running buildings, Energy and Buildings, vol 23,pp175182



Part Two Practice


2.1 Solid ground floors

Most solid ground floors being considered forrefurbishment will be non-insulated.

Original floor: Solid ground slab with screededfinish.There is some uncertainty about the actual in-sulation value of non-insulated ground floors. Itis very dependent upon the properties of thesubsoil. The literature provides values rangingfrom 0.3 for large buildings to 1.0 for small shal-low-plan buildings.The dependence on size isdue to the three-dimensional nature of the heatflow.The outcome is that large buildings mayhave relatively low floor U-values already, andthe cost benefit of floor insulation may be poorerthan for other parts of the envelope.

Insulation options

Option 1: Load-bearing insulation above slabwith reinforced screed above.

This provides some insulated thermal mass,which will offer some of the beneficial functionsof thermal storage associated with heavyweightconstruction.The beneficial effects of thermalmass will be fully realized if dense conductivematerials (e.g. ceramic tiles) are used as a floorfinish, but reduced if finishes such as carpet areused. For screed thickness of up to 75mm, thisamount of thermal storage would be significantfor 24-hour cycles only, due to its isolation fromthe thicker ground slab.

Option 2: Load-bearing insulation above slabwith lightweight decking above.

This behaves as a lightweight construction sincethe mass is isolated by the insulation.The floor fin-ish will have little effect on thermal response.

Option 3: Raised floor with rigid or non-rigidinsulation (quilt) on original floor.

Raised floors are used where access to com-munications wiring and services are requiredacross the whole floor.They may also be of valuewhere underfloor voids are to be used as part ofa natural ventilation system. It must be notedhowever, that with wireless IT technology thedemand for raised floors for IT servicing has di-minished.

Option 4: Replaced slab with rigid insulationbeneath.

This would only take place in major refur

Documents

Handbook of Sustainable Refurbishment