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Preface
This document presents the integration of design for disassembly in the facade industry and serves
as final thesis of my Master of Science at Delft University of Technology. The work has also been
carried out in cooperation with and facilitated by ARUP in Berlin. The thesis committee consists of:
Marcel Bilow, Arjan van Timmeren and Linda Hildebrand, I wish to thank them for their helpful
contributions so far and look forward to continuing the good cooperation.
I advise the reader to not hesitate to contact me on any façade design related topics.
Enjoy the report!
Matthijs Bloemen (Delft, April 2011)
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Contact information title Design for Disassembly of Facades track Master of Science Building Technology, Façade Design student name Matthijs Bloemen student ID 1140361 student address Anklamerstraße 31, Berlin, Germany e [email protected] t +31 (0) 6 45742513 t +49 (0) 16 05717050 main mentor Dipl.‐Ing. M. Bilow chair Design of Construction e [email protected] t +31 (0)6 20358179 2nd mentor Ir. A. van Timmeren M.Sc. Ph.D. chair Green Building Innovation, Product Development & Sustainability e [email protected] t +31 (0)15 2784991 t +31 (0)6 55800458 3rd mentor Dipl.‐Ing. L. Hildebrand chair Design of Construction e [email protected] t +49 (0) 176 640 45 309 4th mentor Ir. M.W.M. van den Toorn Chair Landscape Architecture e [email protected] t +31 (0)15 27 84149
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Terminology
Combustion: The burning process of waste to generate electricity
Commercial facade: The building skin of a commercial building (e.g. office buildings or stores)
Container glass: Glass used for making e.g. bottles.
DfD: Design for Disassembly, designing with the intention of simplifying its end of
life time disassembly or by increasing the recycling opportunities
DfD Objective: An end of service life scenario to strive for when designing for disassembly
DfD Strategy: A design tool to strive for a design suitable with a DfD objective
EoL: End‐of‐Life, refers to the end of a product lifetime (a vendor will no longer be
marketing, selling, or promoting the product)
EoL scenario: possible outcome for elements/materials after service life
EPR: Extended Product Responsibility
Float glass: Special highly transparent and strong sheet glass used in the facade industry
Glass cullet: Old glass used in the oven as a catalyst for the melting process
IGU: Insulated Glass Unit; two float glass panes combined to one unit.
LE: Life Expectancy; estimation on a lifespan of material or element
Natural environment: All living and non‐living things that occur naturally on Earth
Refurbishment: The process of maintenance or repair of building components which are
either technically or aesthetically out of date. In this thesis refurbishment
will only focus on facade components.
Service life: The façade’s useful life
Sustainable design: Is a philosophy of designing physical objects, the built environment, and
services to comply with the principles of economic, social,
and ecological sustainability.
Waste: Materials that have no use anymore
GFRC: Glass Fiber Reinforced Concrete
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Abstract This thesis is motivated by the fact that today the building industry is a significant waste contributor.
Especially at the end‐of‐life of the building it causes an enormous impact on the environment. Waste
will be reduced by extending the lifetime of the short term buildings, and therefore the façade
replacement for the commercial buildings must be encouraged. Though the result of waste due to
the mixture of materials remains a problem during the end‐of‐life process, this barrier mainly comes
from current construction practices that view the assembly as a unidirectional practice with an end
goal of producing a final façade/building. A more cyclic or closed‐loop view recognizes the need to
consider, at the design stage, the disassembly process as well as the assembly process. Design for
disassembly expresses such need. These strategies, which are in this thesis applied to an example
facade of Arup, show possibilities to reduce waste by redesign.
Design for disassembly originates from industries in product design and is driven by regulations. In
architecture, the disassembly process is undervalued and regulations are expected in the near future.
Learning from the product design and applying design for disassembly strategies, more waste
reduction is achieved by focusing on an element of the facade. In response, two studies are applied
on the example facade to find the element with potential for improvement ‐ end‐of‐life and life‐
expectancy study. The glass unit element has the most potential to decrease the waste by improving
its end‐of‐life:
The life‐expectancy study showed that the primary sealing, between the glass and aluminium,
keeps the glass unit airtight. The sealing is one of the weakest links. It is vulnerable to UV‐
radiation and has a limited elastic capability when heat expansion of glass occurs.
The end‐of‐life results showed two critical points related to the glass unit: the glass is currently
down‐cycled due to the inseparable materials used within the unit and due to the integration
into the container glass recycling process. Additionally, the float glass of the glass unit accounts
for 61% of total waste weight of the façade.
Taking the reduction of waste into account during the redesign, there are 4 objectives when applying
design for disassembly strategies ‐ adapting the glass unit by extending its service life, reuse of the
glass unit, reuse of glass or glass recycling. The two study results showed that the most realistic
objective for the redesigns is to change the current down‐cycling of glass to a recycling process to
decrease the waste.
Results of the redesigns are visually presented in the end‐of‐life framework and give a clear
perspective on the process. It shows that it’s possible to integrate glass in facades for recycling, but
not with the techniques that are currently applied on the glass unit.
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Table of Contents
Preface ..................................................................................................................................................... 3
Contact information ................................................................................................................................ 4
Terminology ............................................................................................................................................. 5
Abstract ................................................................................................................................................... 6
1 Introduction ..................................................................................................................................... 9
1.1 Research motivation ................................................................................................................ 9
1.1.1 Waste in the building industry ........................................................................................ 9
1.1.2 The need for proper disassembly .................................................................................. 11
1.2 Problem statement ................................................................................................................ 11
1.3 Thesis goal and research questions ....................................................................................... 12
1.4 Redesign Approach ................................................................................................................ 12
2 Design for Disassembly (Literature Study) .................................................................................... 14
2.1 Disassembly evaluation ......................................................................................................... 14
2.1.1 Timing: Life Expectancy theory ..................................................................................... 14
2.1.2 Method: End of Life theory ........................................................................................... 15
2.2 DfD applications .................................................................................................................... 19
2.2.1 DfD in product design .................................................................................................... 19
2.2.2 DfD in Architecture ........................................................................................................ 20
2.3 DfD methodology .................................................................................................................. 21
2.3.1 DfD objectives ............................................................................................................... 21
2.3.2 DfD Strategies ................................................................................................................ 23
2.4 Reference studies on DfD in facade design ........................................................................... 25
2.4.1 WTC Amsterdam ........................................................................................................... 25
2.4.2 Office XX ‐ Delft ............................................................................................................. 27
2.4.3 Empire State Building .................................................................................................... 28
2.4.4 Conclusion ..................................................................................................................... 29
3 Focus element DfD ........................................................................................................................ 30
3.1 Facade selection .................................................................................................................... 30
3.1.1 Boundary conditions ..................................................................................................... 30
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3.1.2 Selected façade: Galeria Kaufhof .................................................................................. 30
3.2 Façade Life Expectancy study results .................................................................................... 32
3.3 Facade EoL study results ....................................................................................................... 33
3.3.1 Façade EoL product: Frame (aluminium) ...................................................................... 36
3.3.2 Façade EoL product: Structure ...................................................................................... 36
3.3.3 Façade EoL product: Insulated glass unit (IGU) ............................................................. 37
3.3.4 Façade EoL product: Cladding ....................................................................................... 38
3.3.5 Façade EoL product: The rest group .............................................................................. 39
3.3.6 Façade EoL critical points summary .............................................................................. 40
3.4 Selected element: IGU ........................................................................................................... 41
3.4.1 Motivation for element selection .................................................................................. 41
3.4.2 Background information on IGU ................................................................................... 42
4 Redesign ........................................................................................................................................ 46
4.1 Redesign Plan ........................................................................................................................ 46
4.2 DfD Objective & Strategies .................................................................................................... 46
4.2.1 DfD Objective................................................................................................................. 46
4.2.2 DfD Strategies ................................................................................................................ 49
4.3 Redesign A ............................................................................................................................. 51
4.4 Redesign B ............................................................................................................................. 53
4.5 Assessment ............................................................................................................................ 56
5 Conclusions and Recommendations ............................................................................................. 62
Table of Figures ..................................................................................................................................... 67
References: ............................................................................................................................................ 69
Appendix A: Crowther ‘s DfD strategy list in detail ............................................................................... 71
Appendix B: Galeria Kaufhof sections (1:10) ......................................................................................... 73
Appendix C: On‐ & Off‐site built facades .............................................................................................. 75
Appendix D: Drawings of all designs (2:1) ............................................................................................. 77
Appendix E: Calculation outcome on different cavity contents ........................................................... 78
Appendix F: Assessment with Trisco outcome ...................................................................................... 79
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1 Introduction
1.1 Research motivation
1.1.1 Waste in the building industry
The building industry has an enormous impact on the environment. There are different types of
impacts. An LCA1 study quantifies this and shows when a certain impact is caused. The building
industry is globally responsible for 30‐40% of exhaust emissions and up to 60% of all produced
volumes of waste (Hegger et al. 2008). This results in for example pollution and resource depletion,
and has severe consequences on every living organism on earth. Clean water, fresh air and fertile
land are what it needs for living and therefore it may not be limited for use.
There is a worldwide agreement2 on the need to reduce the quantity of building material
consumption and to reduce building waste to create a sustainable environment. However,
regulations and laws, which I think people in developed countries live by, do not yet enough
stimulate people to act in a sustainable way. These facts have motivated me further research in
sustainable design with a focus on decreasing waste.
When thinking of a building, people tend to think of it as just that ‐ a single building: conceived,
designed, constructed, used and disposed of as a complete entity. However, because different parts
of the building have different life spans it should be considered as a structure made out of layers
(Brand 1994). Throughout the buildings lives they may, for example, change in functionality or in
appearance, but most buildings have long lives.
Brand views that the ethics and values that support the building are just as important as the
technical aspects, and that it should be treated as a `Darwinian mechanism´3. He divides the building
into layers with different rates of change for its components and he states that a building is always
‘tearing itself apart’.
1 The life cycle assessment has been accepted within the environmental research community as the only legitimate basis on which to compare alternative materials, components and services and is, therefore, a logical basis on which to formulate building environmental assessment methods (SETAC, 1993). 2 Formulated in 1987 by World Commission on Environment and Development (Brundtland Comission):" A development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (World Commission on Environment and Development 1987). 3 Something that adapts over time to meet changing needs
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Figure 1, Average building lifespans (left) and building layers lifespans (right) (Brand 1994, Crowther 2001,
Yeang 2008)
If buildings slowly fall apart, how comes that different types have different life spans? Buildings
constructed before 1940 tend to have a longer life span than the ones built after this point in time.
The average residential building has a longer life span than a commercial building4, as the latter is
used for a shorter time and is less adaptable (Yeang 2008).
Figure 2 shows that because waste is generated throughout the lifecycle of a building. The
environment is impacted in various ways. This figure also shows that there must be focus on the
disposal phase when attempting to decrease the amount of waste as this phase has the highest
environmental impact.
4 Average lifespan of buildings (USA): residential 100 years and commercial 20 years. (Yeang 2008)
A = air impact T = transportation W = water impact R = refuse / waste E = earth impact H = health of people P = power consumption S = social impacts L = landscape picture Tr = trouble risk F = flora & fauna € = ecomomic aspects
Figure 2, Swiss roll waste management (Woon/Energie1991)
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The ‘structure’ layer of a building has the biggest volume and highest weight and can be seen as the
main problem in waste generation. However, because the average lifespan of the skin, also known as
the façade, is significantly lower it too has a large impact on the environment. The façade can often
be seen as the weakest link of a building when looking at the average lifespan. There is potential for
decreasing waste in the building industry when applying sustainable design to commercial facades.
1.1.2 The need for proper disassembly
Reducing the environmental impact during the disposal phase of a building can be done by either
optimising the reuse and recycling processes, or by prevent the problem by changing the design
before the building is constructed.
Current strategies like the ‘3‐R’ (Reduce‐Reuse‐Recycling) and the more accurate successors ladder of
‘Delft’ or ‘Lansink’ are examples to reduce the impact on the environment of existing waste. The
Swiss roll diagram in Figure 2 shows that there are still barriers to successfully recover and reuse
materials and components. The current practice during demolition or re‐structuring of buildings
includes the mixing of materials and thereby creating a low reuse ratio. This barrier is mainly from
current construction practices that view the assembly of materials and components as a
unidirectional practice with an end goal of producing a final building. Such a linear view of the
building environment limits the End of Life (EoL) scenarios when a building has reached the end of its
service life.
Changing the design to reduce the environmental impact in the disposal phase can improve end of
life scenarios. According to Papanek (1995) there are several design strategies that should be
considered when the objective is to limit the impact on the environment. By designing for
manufacturing, assembly, maintenance, cleaning and disassembly recovery and reuse of materials
can be improved. A more cyclic or closed‐loop view of the built environment and the materials within
it will recognize the need to consider, at the design stage, the disassembly process as well as the
assembly process. Such consideration can be expressed as the need to design for disassembly (DfD).
1.2 Problem statement
Today a building is a significant waste contributor at the end of its life. The façade is a weak link when
comparing the average lifespan of all elements of a commercial building. The end‐of‐life process of
the facade includes the mixing of materials and thereby a low reuse ratio, this holds back the
refurbishment process of buildings.
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1.3 Thesis goal and research questions
Thesis goal: Apply DfD strategies on a commercial facade to decrease waste.
Main question: How can the facade be designed taking its EoL into account to reduce waste?
Sub questions:
‐ What is relevant when designing for disassembly in façade design?
‐ Which element of the façade has redesign potential to reduce environmental impact in the EoL?
1.4 Redesign Approach
For a scientific research in this thesis strategies are used to redesign an existing design and the
outcome will be discussed in detail. It is important to have a broad applicable outcome and therefore
an approach has to be made for a clear redesign focus. Findings from the literature study are used to
guide the redesign approach:
In the literature study which is covered in Chapter 2, one can find the disassembly methodology and
timing, followed by theory on background and applications of Design for Disassembly (DfD), and
three reference studies showing the current practice in facade DfD.
Findings in literature motivated the following three steps;
‐ Facade element research
‐ Selection procedure
‐ Redesign preparation
Facade element research
Study shows the difference between DfD in architecture and in product design. Buildings are much
more diverse compared to standardised products, which is why DfD is less generally applicable in
architecture today. Though similarities exist between the facades, it is especially elements of a
façade that resemble standardisation. Considering DfD to decrease the produced waste there is more
progress to be made when focussing on an element that is applied in multiple facades.
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Selection procedure
To apply DfD strategies on a facade element, first an example facade must be selected. This thesis
study has the privilege of using the project library of Arup and specific conditions are formulated to
make the select one of many facades that suits the purpose of finding an element that allows
potential for redesign. When a facade is selected two methods are used for the element selection; a
Life Expectancy (LE) study to find weakest link of façade in terms of an average lifespan, and an EoL
study to find element with the highest potential to decrease waste in the future. Critical points of
both studies will point out the element with most potential for DfD improvement. This is covered in
chapter 3.
Redesign preparation
As a first step a DfD objective is formulated and (then based on that as a second step) several DfD
strategies are taken from the literature. The objective is with the highest potential for an EoL
improvement by design is selected.
In general a redesign is executed on different levels. The architect describes the visual aspects of a
redesign, the consultant (Arup) creates design concepts based on theory and experience, and the
manufacturer creates a detailed executable design. For the purpose of this report a concept level will
be generated for the redesign, this suits both Arup and TUDelft. It is important to prevent interaction
with the other two levels, e.g. a material expert at the manufacturing level could possibly think of
several downsides to this redesign. Design conditions will clearly create boundaries for validating the
design on the concept level.
The redesigns for an element of the selected façade are presented in chapter 4 and conclusions and
recommendations are added in chapter 5.
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2 Design for Disassembly (Literature Study)
2.1 Disassembly evaluation
2.1.1 Timing: Life Expectancy theory
In order to know which elements of the example facade can be trusted to last for a certain period
and which are more likely to fail, it is important to know the technical life span to prevent the waste
creation. The real life span of an element is hard to define and depends on many different factors,
such as the original quality, operational strain, and maintenance.
According to Berge (2009) it takes at least 60 years of study to determine whether a façade element
has a 30 year life expectancy. Therefore, the Life Expectancy (LE) theory only states expected and
average life spans. The German Federal Office for Building and Regional Planning collects data from
interviews and literature studies. The expected life span of facade elements is reported by them and
taken into account for design by Arup but also TU Delft.
Figure 3: Insulated glass unit failure of the building EnBW in Stuttgart Germany. Water has come inside this decreased the thermal and visual performance. (Ebbert 2010)
A typical example of the EnBW in Stuttgart in figure above shows how an insulated glass unit can
cause a total facade failure. There is a leakage of humid air into the cavity of the unit. By
condensation on the inner glass surface water started the moulding process which resulted in a
decreasing value of thermal insulation and level of transparency. The main problem of this facade is
that is built in such way that replacing the unit is only possible by disassembling the whole facade
due to interlocking connections in the ‘u’ shaped building.
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The Arup structural engineering group uses a tool that integrates design plans, logistics during
construction, maintenance programs and disassembly procedures. The Building Information Model
(BIM) can be viewed as a database on a building. It is also a tool that can be used to look up when
certain elements of a façade reach their expected end of life, but the user can also add information
that on unexpected failures (which is beneficial for future users).
2.1.2 Method: End of Life theory
Limited literature on the EoL of facades is available. Information was therefore gathered from the
industry and scientists. In this report the EoL is divided into four phases (phase 0, 1, 2 and 3). It
describes the phases from the planning on how to disassemble to the further treatment of materials.
Focussing on the creation and the treatment of waste the energy used to complete certain steps are
undistinguishable due to the now‐a‐days rising costs of oil and gas and the awareness of the
environmental impact stimulated by for example the production of CO2. The embodied energy will
therefore be integrated in the explanation of the phases.
Phase 0: EoL decision
The façade often nears its end of service life when the owner decides to. At that moment in time the
whole building is often considered for refurbishment. This is driven by technical failure and aesthetic
values, economical and legal reasons (Ebbert 2010). Prior to the decision the owner will likely run
economic analyses. When the building is no longer economically viable, the decision is taken to
invest in the EoL.
The on‐site procedures for the EoL of a façade vary and depend on the building. Besides the shape of
the façade, governmental regulations and economical reasons drive EoL methods. Markets and
government determine the costs of separated or mixed disposals. Governmental regulations are
implemented to encourage safety (e.g. removal of hazardous materials).
Phase 1: Demolition or disassembly
This first phase is key as the demolition or disassembly path will either result in waste or proper
material reuse respectively. This phase is divided into three alternatives: demolition, raw disassembly
and disassembly. With different energy input levels the facade is taken from the main structure, the
more accuracy the more energy is needed to perform. All alternatives aim to bring the product to a
certain portable size for transport
Demolition
In this method the entire façade is demolished and all materials are considered waste. Demolition
was often applied in the past when recycling markets were less developed.
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In Europe buildings above the seventh floor are generally diamond‐sawed into manageable pieces
and lifted down with a crane. The lower levels, up to and including the seventh floor, are crushed
between the claws of a hydraulic rock breaker and broken down into rubble (Boin 2004).
Raw disassembly
The most frequently used technique today is raw disassembly; the structure is separated into
material groups for reuse, recycling and down‐cycling. This method leaves sufficient room for
optimization as large quantities of materials are still regarded as waste or being down‐cycled.
Figure 4, from left to right, demolition of the burned down architecture faculty in Delft with a wrecking ball
(Sanoma Digital Group 2008). 122 Leadenhall street in London halfway a raw disassembly process (Rasmus
Broennum architects 2009). Vodafone Hoghhaus also known as Mannesmann tower is properly disassembled.
The exchange of the 1950s façade with new units, as seen above (RKW 2009).
Different techniques can be applied during raw disassembly. Commonly used in Europe is the folding
technique (Boin 2004): the walls of the building are then “folded” inwards, rather like the sides of a
box, allowing recovery of facade materials.
Alternatively, a Japanese company (Kajima) uses the ‘cut and take down’ method. The method is
efficient and reduces pollution from noise and dust. It is done by a bottom–top approach starting
with the ground floor and a temporary construction lowers the entire building until there is a new
ground floor level.
Disassembly
Disassembly with care is not commonly applied. Recently constructed facades with high material
reuse values and with assembly knowledge available may be disassembled with care. Unitised
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facades have proven examples e.g. Schüco mock‐up models (Artzman 2010) and the example in
figure 4.
Phase 2: Transport, sorting and cleaning
The second phase includes transport and sorting and cleaning and is one that is often considered a
step of minor importance in between two other phases. Disassembly with care shows that material
conservation receives high priority. Similarly to the transport phase prior to assembly materials and
elements are transported in pallets often protected to prevent damages on the way.
A commonly applied technique is to sort the different materials of the facade in different on‐site
placed containers according to the possibilities in the third phase. An agreement is usually made
between the responsible company in phase 1 and the responsible company in phase 3. In case the
materials/elements are reused they are directly brought to next on‐site location or they are
temporary stored before transported again. Storages have to cope with the large amount of
materials and, depending on the type, require special storage conditions. Glass for example can be
visually damaged when in contact with water for a long period. The financial consequences are often
high and this discourages reuse.
Transport has an impact on the life cycle of recyclable materials especially now with the high oil
price. According to Lichtenberg (2005) it can be a major factor in actually creating a net increase in
the environmental impact of recycling over using new materials. He mentions traffic problems in The
Netherlands (25% of all traffic is building industry related), ‘heavy’ weight transport that damages
the roads and the widely spread locations for further treatment. If one could extend the life of a
building, one could reduce the impact on the environment through decreased transport.
Sorting is separation from a mixture of materials done manually or mechanically. Figure 5 shows
different separation techniques that are applied today. The applicable separation technique is driven
by the characteristics of a material in the mixture. If needed, several techniques will be used and
prioritised based on efficiency. For example big elements and metals with a magnetic permeability
are (easily) separated from the mixture first.
In case the materials are firmly attached to each other, cutting and shredding techniques are applied
for further separation processing. Cleaning also separates materials from each other by using other
material(s).
Separation on: Separation techniques
Size Manual Separate recoverable materials
Magnetic permeability Screening Make a size separation
Colour Jigs Density separation, removing plastics from metals
Physicochemical property Magnets Remove ferrous metals from non‐magnetic materials
Electrical conductivity Eddy current Recovery of non‐ferrous metals, aluminium
Solubility Electrostatic Remove conductors from non‐conductors, glass
Figure 5, Separation criteria and techniques. (Hendricks 1999)
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Phase 3: Waste or material management
All waste management is based on the three ‘R’ concept: 'Reduce – Reuse – Recycle’. It is a
management approach for all waste. There are more sophisticated models that calculate the best
results on ecological level, such as the `Ladder of Lansink´. In 1980 the Dutch government introduced
this seven stepped hierarchy system. The ladder ranks the waste by impact to the environment: the
first option is better than the second (it has less impact on the environment) and so on.
Instead of only using the term waste management, in this report a deviation is made between
material and waste management. Material management includes treatments maintaining the
material quality (Reuse – Recycling).
Please find below a list of different waste and material management techniques:
Reuse
Reuse is to use an item more than once. This includes conventional reuse where the item is used
again for the same function and new life reuse where it is used for a new function.
After disassembly has taken place reuse can be considered and may require cleaning, transport or
other services. When a certain material/component has a longer life expectancy, this
material/component has still a value for a second user. More can be earned in comparison with
recycling and therefore automatically reuse is preferred, besides the additional advantages of saving
time, money, energy and resources. But unfortunately if the quality of the material/component
cannot be guaranteed for an entire second life or a buyer is simply not found reuse is not an option.
The reuse of the material can be either primary (in its original form) or secondary (in modified form).
Primary reuse means that the item is reused for the original intended purpose and does not require
any additional reprocessing. Secondary reuse involves employing an item again but for a different
purpose, and requires modifying it in a limited way.
Recycling
Recycling should be the breaking down of the used item into raw materials which are then reused to
make the similar items. Recycling can be done on different levels; this depends on the breaking down
and remaking process. There are two methods for breaking down a material; melting or pulverising.
Steel for example can be melted and brought back to almost its original state. Recycling can be
assessed by looking at how much material is returned to its original state after breaking it down.
The term recycling is used in different ways. Many companies publish their products as if they are
made of or are able to be recycled, but in contrary it often ends up in the waste management
process. This (growing) awareness of miscommunication is rewarded as sustainable development is
encouraged by the government. An example is the funding of the Dutch government for using
materials with less impact on the environment than a traditional version.
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Down‐cycling
Down cycling is a form of recycling and occurs if the original product cannot be remade. It is often
used for products with a lower physical and mechanical performance compared with the original.
This process prevents the material from becoming waste, but opinions differ about its environmental
impact because there is little chance for recycling and with another down‐cycling process it will end
up in landfill. In this thesis a difficulty scale is added to the down‐cycling process; a low and high
grade of down‐cycling
Up‐cycling is also part of this class. The material is upgraded to a higher quality level in a new life
cycle. This is however never planned beforehand and not applicable to any façade elements.
Incineration
Incineration is the combustion of organic materials and/or substances. Incineration of waste
materials converts the waste into incinerator bottom ash, flue gases, particulates, and heat, which
can in turn be used to generate electric power. The leftovers, ash and gasses, will be dumped in
landfills or further treated to eventually be disposed as steam with CO₂ gasses in the atmosphere.
Incineration also reduces the volume of material that will be disposed in a landfill and is currently
preferred above direct dumping in landfills.
Incineration can be viewed as the lowest recycle stage, because it generates electric power as a
down‐cycle product. But it can also be simplified as getting rid of waste by burning.
Landfill
Land filling is a definite last step. At that point in time, nobody wants to deal with the waste
leftovers. It is buried in landfills, or dumped in water and in case of gasses in the air, with the intent
to be forgotten. This form of waste treatment has boundaries and especially in a country such as The
Netherlands where space is limited, it motivates reuse and recycling.
2.2 DfD applications
Today, the disassembly process is relatively undervalued. It is expected that significant value can be
gained by taking the disassembly process into consideration from an environmental angle during the
design phase.
2.2.1 DfD in product design
Design for Disassembly (DfD) was first applied in product markets. Products are less complex, less
enduring, and more mobile than buildings, and so there are far more advancements in product
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disassembly technology. DfD is driven by regulations, for example, the Extended Producer
Responsibility (EPR) Act of the European Parliament and Germany’s End‐of‐Life Vehicle Act in 2002.
The act forces manufacturers to take back from consumers their products after their service life. On a
larger scale reuse or recycling can be stimulated. As manufacturers began taking their products back,
they established a system by which they could reuse their raw materials in the manufacturing of new
products. This closed loop system is dependent on disassembly, and therefore significant innovations
have been made in product disassembly in the past decade.
Lean thinking has influence on the design process; ‘this approach tries to manage and improve
construction processes with minimum cost and maximum value by considering customer needs’ (LCI
2007). Lean is now‐a‐days well integrated into the product design and a typical outcome is the
assembly‐line invention to improve the assembly process. DfD can adapt to this methodology and
successfully integrate into industries like the façade.
2.2.2 DfD in Architecture
DfD in architecture is not common, but it may be expected that similar regulatory approaches soon
be extended into the building industry. This could require facade assemblers to take responsibilities
of reuse, recycling or disposal of facades at the end of their service life. Participants in this industry
should take these changes into account and integrate the market by setting the standards rather
than awaiting new regulations.
Several architectural scientists have already been exploring DfD in other industries, for example
according to Guy & Ciarimboli (2005) the definition of DfD for architecture is the following:
‘DfD is a designing principle that allows future changes in buildings and its disassembly at the end of
its service life. The process goes beyond developing the assemblies, components, and materials, as it
also covers construction techniques and information and management systems. The recovery of
materials is intended to maximize economic value and minimize environmental impacts’.
Since humankind first began to build their impermanent structures DfD existed in the architecture. In
parts of Japan permanent houses have been constructed allowing easy disassembly for the last 1300
years, due to the frequent (20 years) reconstruction driven by the number of earthquakes. DfD is also
essential to exhibition pavilions, entertainment structures and military facilities which are often used
only temporarily. It is a discussion whether this type of structures belong to architecture, because
designing for a short life span gives a typical outer appearance. Renzo Piano, has proven differently,
designed the IBM travelling pavilion and was successful in giving the presence as a building it did not
result in a mechanistic and repetitive structure. Temporary buildings have to be simple and therefore
concentrate so much on their budget into solving pragmatic assembly and deployment problems that
there is nothing left to make the architecture. (Kronenburg 2008)
Other applications of DfD in architecture can be partly seen in for example the Seagram Building in
New York City. The integration of pure materials such as metal, glass, stone and concrete increases
the reuse and recycling capabilities. This technique but also the use of bolt connections is typical DfD
principles, often applied in modern architecture (Guy & Ciarimboli 2005).
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In the facade industry the level of integration of DfD is similar to architecture. Existing DfD strategies
for architecture only cover the whole building with no specific attention for the facade. One
remarkable assembly development must be mentioned considering DfD; Unitised facade systems
have modular design which can work ideally for refurbishment (figure 6). Appendix C further
discusses the comparison between on‐ and off‐site built facades in relation with DfD.
Figure 6, Three DfD examples. Left: The temporary building of the faculty of architecture Delft after the main
building burnt down (tudelft). Middle: Elegant joint of the travelling pavilion of IBM by Renzo Piano. Right: Ideal
scenario for DfD in the facade industry – Façade is disassembled on the same way it’s assembled. New
upgraded façade with the same outer appearance on top, old façade is disassembled with the same crane
(RKW 2009).
In other industries regulations stimulate a proper DfD process , whereas in the building industry such
regulations do not exist. Other factors can however also stimulate DfD in the building industry. The
green building certification system (e.g. LEED) ‘provide building owners and operators a concise
framework for identifying and implementing practical and measurable green building design,
construction, operations and maintenance solutions. … to improve energy savings, water efficiency,
CO2 emissions reduction, improved indoor environmental quality, and stewardship of resources and
sensitivity to their impacts’ (USGBC 2011). Beside the broad orientation on the industry and the not
directly applicable solutions, this not legally obligatory design tool is only used in projects with a
suitable financial plan.
In short, the building industry has potential for improvement for Design for Disassembly to decrease
its waste impact.
2.3 DfD methodology
2.3.1 DfD objectives
When applying DfD on a building, one should always design in line with an end of service life
objective. The underlying goal is to decrease waste in volume.
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Fletcher et al. (2000) tried to stimulate DfD in the building industry by translating DfD objectives from
the ‘industrial ecology’5. He described four objectives; reuse, repair, reconditioning, and recycling of
materials. Guequierre and Kristinsson (1999) have also identified a number of what they call ‘end‐of‐
life scenarios’. Unlike Fletcher and other industrial ecology researchers, Guequierre and Kristinsson
are not focussing on the design of new buildings or products, but on the analysis of existing buildings
to determine the most appropriate scenario. This results in a model with four ‘end‐of‐life scenarios’:
repair of products, recycling of materials, and two non‐reuse scenarios incineration and landfill.
Some of these objectives or scenarios are more environmentally friendly than others. Reuse is
preferable to repairing, which is in turn preferable to recycling. There is a hierarchy for the objective
with the least processing requirements, the least energy input and the least waste generation, in
short the least environmental burden.
Crowther (2005) subdivides the building in different levels to differentiate between different
objectives:
‐ Systems level: Adaptable building which can change to suit changing requirement
‐ Product level: The products of a building are designed to allow upgrading, repair and
replacement
‐ Material level: When a product is broken down to its composite materials these may be
recycled
The following DfD objectives are derived from the different DfD objectives from Fletcher (2000) and
Guequierre and Kristinsson (1999) by combining the above levels of Crowther (2005):
1. Adaptation: Design a facade to allow changes during its entire service life. By upgrading and
repairing the façade the lifespan is extended and waste outcome is reduced, but adaptation has its
limits and eventually even adaptable facades will become obsolete. The critical factor when
designing for adaptation is to consider the interface between the elements of the façade to allow
easy removal of the shorter lived elements without damage to the longer lasting elements allowing
components to be replaced in the facade during its useful life.
2. Product Level Reuse: Design a facade to allow for reuse as a whole product after its service life.
Reusability is however a function of the age and durability of a material
3. Material Level Reuse: Design a facade to allow for reuse of its materials after its service life. To
evaluate the value of reusing a material the technical life span of facade elements is key. The actual
life span of an element depends on many different factors, such as its original quality, the endured
operational strains, and the applied maintenance. Using good conditioned materials would be
essential during manufacturing of facades.
4. Recycling: Design a facade to allow for recycling its elements after its service life. Recyclability
measures the capacity of a material to be used as a resource in the creation of new products of the
same quality level. Recycling is naturally not as environment friendly as reuse or adaptation.
5 Industrial ecology identifies many ways to reduce the environmental impact of a product or service, e.g. car industry.
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2.3.2 DfD Strategies
After the designer has determined a DfD objective, it is recommended to apply strategies to come to
a design. Different design strategies are found during this study and there are several lists of
strategies published by scientist with an architectural orientation. These lists are quite similar to each
other, but vary by means of objectives and in dimensions. Only one list from Crowther (2005) ranks
strategies in importance based on the design objective. Crowther realised that some strategies are in
conflict with each other. The need to minimise the number of different material types will not always
be compatible with the need to use light weight materials. In such a case the benefits from each
design objective may need to be compared. The designer will get a better focus on the design
objective by using this list during the design process, and thereby enlarge the chance for a successful
disassembly.
In figure 8 the list of Crowther is presented and in the appendix A an explanation of the strategies
can be found. Please note that these architectural design objectives are applicable to the facade; the
objectives recycling matches with ‘material recycling’, ‘component remanufacture’ to reuse on
material level, reuse on product level matches with ‘component reuse’ and adaptation matches
‘building relocation’. There are differences between the objectives, but the strategies strive for the
same. One example strategy will be explained:
Nr. 4: Avoid secondary finishes to materials. A secondary finish such as coatings may contaminate the
base material and make recycling difficult. So in case the finishing is preferred or even required, use
materials that provide their own suitable finish or use mechanically separable finishes. Exceptions are
some protective finishes such as galvanising. This secondary finishing may still on balance be
desirable since they extend the service life of the component despite disassembly or recycling
problems.
Figure 7, coating is added onto the glass by a liquid spray. This is a secondary finish on the glass surface and must be prevented (Hall 2008).
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An interesting characteristic appears when studying the strategy list. Similarities can be seen with the
‘lean construction’ theory (2.2.1). Allow for parallel disassembly (strategy nr. 20) is an example of a
strategy with a product design origin. It can therefore be said that these strategies have more impact
on a product design than an architecture design process.
Figure 8, Strategy list for DfD made by Crowther (2005). This list distinguishes itself from other DfD lists by ranking the strategies on the DfD objectives. By using this list during the design process, the designer can focus better on the objective, and thereby enlarge the chance for a successful disassembly.
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2.4 Reference studies on DfD in facade design
Three reference studies are presented showing different DfD cases. The WTC Amsterdam façade is
proven to be able to adapt to new requirements, the Office XX is recently built and is designed to
have a limited life span and the Empire State Building shows an efficient refurbishment technique.
2.4.1 WTC Amsterdam
A typical example of the refurbishment process is the WTC Amsterdam. It is constructed in 1985 and
has been refurbished, partly demolished and extended with two new towers in the period from
1998‐2004. This was driven by a changing urban structure, a need to upgrade the thermal
performance and a desire to increase the incoming daylight for internal comfort.
WTC Amsterdam Refurbishment involved parties The owner ING RealEstate, Trimp & van Tartwijk Main contractor BAM Sub‐contractor Scheldebouw and C.A.deGrootSupplier unknown Waste processor unknown
Figure 9, WTC Amsterdam: parties involved in the refurbishment
The main contractor (BAM) was requested to organise the partly demolition and refurbishment of
the old building and the new building construction. BAM inspected the old building and planned the
processes taking regulations into account. C.A.deGroot demolished a small part of the main
structure. Scheldebouw, the builder of the facade in 1985, was requested to upgrade parts of the old
facade and to build the facade for the new towers.
In 1985 the façade was panelised and mounted using a doke & terminal. During the refurbishment,
terminal strips were removed so that the single glass panels could be replaced by green coloured
double pane units. The insulating sandwich panels were sawn of at the top to create a bigger area for
daylight to come inside. The elements were taken down during the refurbishment and collected by
companies who recycled or further treated the materials. Materials included glass, alumium,
gaskets, elements of a sandwich panel, and other small parts like screws. Left overs on‐site and after
further treatment were brought to final waste processors.
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By giving the initial facade builder the assignment to refurbish the building the facade was treated
with care. With a minimal treatment they upgraded it to the new requirements. The advantage of
knowledge on the old facade system and its assembly method pays off.
This facade is a good example of DfD with the objective of adaptation. The following are typical
characteristics of adaptation for general application:
‐ disassembly of the terminal strip through unscrewing
Figure 10, from left to right: assembly process of old facade in 1985. Internal view on façade (right): one of the refurbishment requirements was to enlarge the glass surface for more daylight.
New: (The elements filled with grey)
‐ Insulated glass unit, instead of single pane window.
‐ Outer aluminium frame terminated to the structural inner part, replacement.
‐ Aluminium cover cap, replacement.
‐ Horizontal structural aluminium frame, replacement after removing top sandwich panel.
‐ All EPDM gaskets, replacement. ‐ Cap covering mineral wool of the
sandwich unit, after cutting the top part off.
Old:
‐ Structural aluminium frame, vertical and partly horizontal.
‐ Sandwich panel.
Figure 11, vertical section of refurbished facade with new elements. Critical point: connection of sandwich panel with load bearing facade structure.
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‐ parallel disassembly of the aluminium cap and strip
‐ the re‐filling of the insulated glass unit
On the other hand, a relatively difficult and labour‐intensive disassembly method like sawing was
applied on the insulation panel. Apparently this was the most energy and cost efficient method. A
facade manufacturer does normally not have access to the detailed knowledge of the old facade
components and its assembly method, and would not be capable of performing such an operation.
2.4.2 Office XX Delft
Post Ter Avest architects in Rotterdam planned to build an office with a lifespan of only 20 years in
1999. Instead of focusing on waste reduction this building is based on materials with an expected
economical lifespan.
The financier of this building (Wereldhaven N.V.) has several reasons to invest in this project. Besides
the responsibility towards the environment, they noticed that most office buildings are refurbished
after only 20 years because of the wishes of a new tenant. According to the financier refurbishment
is very expensive and complex, as office buildings are rarely designed to be dismantled. In 1999 they
also expected that costs for dumping waste would rise significantly in the future.
Guequierre and Kristinsson (1999) researched the economics on this project and concluded that in
1999 this was an economically viable decision. They used the BELCANTO tool (figure 13) to compare
the different alternatives from an economic perspective. Does it pay off to build an office and to
disassemble it after 20 years, rather than refurbish it? In this reference it did.
For the purpose of DfD, Office XX is a unique example, as its end of life scenario was pre‐determined.
Though this fixed position brings the constructors in a risk full position. The financiers gave initiative
for this project but especially the constructors have to cope with the uncertainties. These companies
are less paid with the knowledge that they would earn the rest amount of money by further re‐
selling after 20 years.
Figure 12, Office XX building in Delft. Picture taken in 1999.
Client: Tales Group Location: Delft, Netherlands Architect: Jouke Post, Post Ter Avest architects Completed: 1999
Figure 13, BELCATO model: Building End of Life Analysis
2.4.3 Empire State Building
A window refurbishment was completed in The Empire State Building in October 2010. The building's
6,514 windows were refurbished through a new process that reused 96 percent of the existing glass
and frames.
Figure 14, Old (left) and new (middle) glass unit, and the Empire State Building, NYC (right).
29
Serious Materials is the insulated glass unit manufacturer that was responsible for the successful
execution of this project. Figure 14 shows what the difference is between the old and the new
situation.
The contractor upgraded the u‐value to approximately 0,8 W/M2K by integrating two cavities filled
with argon gas sealed by warm edge spacers. The pre‐float glass era panes are reused with care, but
the pioneering process they applied to re‐manufacture the glass unit is remarkable. Serious Materials
reused the existing materials in a dedicated processing centre located within the building. The
hermetically sealed and clean room made it possible to seamlessly retrofit thousands of glass units.
The replacement was performed overnight during the course of seven months, without any major
disturbance to tenants.
2.4.4 Conclusion
A short summary of the valuable points according to the thesis goal are presented here in this
paragraph.
WTC Amsterdam, the disassembly procedure is applied with full confidence by Scheldebouw. The
upgrade of its own facade was easy, quick and efficient. This shows the value of having full
knowledge of the old facade when disassembling it, but it also shows that this type of facade has a
certain value of adaptation.
Office XX, although it’s not sure whether the building will be disassembled in 2019, it’s great example
how to design taking the EoL into account. The finance is always a challenging aspect for the
technical aspects of the building. In this reference it showed that buildings with a limited lifespan are
economical achievable and that refurbishments must be stimulated for economical reasons.
Empire State Building, this reference study shows a great leap in energy efficient façade
manufacturing and the possibilities for proper reuse to reduce a great amount of waste.
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3 Focus element DfD
This chapter covers the process of selecting an element applicable for redesign. This is realised by
selecting a façade and by analysing it through a life expectancy test and the EoL test. The element
must meet certain criteria and will be redesigned for DfD purposes in Chapter 4.
3.1 Facade selection
3.1.1 Boundary conditions
The thesis objective is to redesign a commercial facade to decrease waste. In this paragraph an
actual commercial façade is selected.
The façade selection is driven by a number of boundary conditions. They are listed in a random order
below:
1. Location facade: The location of the façade determines which building regulations apply.
Just like the building regulations, safety and environmental regulations also vary
significantly from location to location. Building a façade. It was decided to select a façade
in the UK, Germany or The Netherlands as these countries have similar and developed
building, environment and safety standards. Additionally, both TUDelft and Arup are
active in these regions.
2. Refurbished façade: It was decided to select a façade that has already been refurbished
at least once. This has the benefit that any problems that occurred in the past can be
addressed in a redesign.
3. Standard façade: It was decided to select a standard façade. This would allow the
outcome of this thesis to be universally applicable.
4. Arup built façade: With the objective of being able to apply the outcome of this thesis to
future Arup projects, it was decided to select an Arup built façade. As a result of this
boundary condition the selected façade will be an on‐site built system. All refurbished
facade projects in the Arup project portfolio are executed on‐site rather than off‐site.
(Please see appendix D for some background on off‐site and on‐site built facades).
3.1.2 Selected façade: Galeria Kaufhof
In 2006 Arup Berlin consulted RKW architects on the refurbishment assignment for the Galeria
Kaufhof in Frankfurt am Main. The façade was selected as it met the boundary conditions.
The shopping centre was built in the 1950s and the façade was refurbished in 2008. Figure 15 shows
the old façade and the refurbished façade.
Figure 16 shows a horizontal section of the Galeria Kaufhof façade. It shows the elements that were
added during the refurbishment. In paragraph 3.4 an element of this façade will be selected. This
element is redesigned for DfD. A drawing showing the materials more in detail can be found in
appendix B.
Figure 16, horizontal section Galeria Kaufhof façade. The red lines point out elements added in 2008, stone wall is part of the original part of the façade. Schale 1:10, see appendix B for more 1:10 drawings
Figure 15, old façade (left) and new façade built in 2008.
3.2 Façade Life Expectancy study results
The Life Expectancy (LE) study shows which materials are the weakest link in a structure, but also
which further damage it can cause to other materials. Like Brand would say: ‘it’s tearing itself apart’ ,
so it’s important to prevent unnecessary waste production if its predictable. The theory is explained
in paragraph 2.3.1. The study results specifically for the Galeria Kaufhof façade are presented in
figure 17 and 18.
Figure 17, Galeria Kaufhof Façade Life expectancy study results. Source: IEMB list (2008).
Figure 18, Galeria Kaufhof Façade LE study results visualized on a horizontal section of the façade. Scale 1:10
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Critical point 1: Glue on impermeable foil. The foils are responsible for a part of the air tightness of
the facade, but after a period of 10‐20 years the glue between the foils fails and air can pass through.
Due to this, the thermal level of the entire facade drops and in extreme cases it can cause water
leakages. Replacement of the glue is not an easy operation. This critical point is deemed to be most
important.
Critical point 2: Primary sealing. The function of the primary sealing is to keep the cavity of the IGU
airtight. Compared with other sealing types the butyl variant performs on a high air tightness level,
but shows many physical weaknesses. It has a lack of elastic performance during heat expansions
within the unit and it is vulnerable for UV‐radiation. The consequences are that the thermal and
visual performance of the whole unit decreases; this will be explained in the following four
arguments.
‐ Instead of 90% argon gas in the cavity, after 20 years it contains 75% and the loss per year
will only increase (Hall 2008). Result: more heat loss. In appendix D two calculations are
shown of the two argon gas filled cavities (90% and 75%). The heat loss increased with 0.7
W/m2K.
‐ Moisture from incoming air condensates on the glass surface. Result: more heat loss
λ humid = λ dry *(1+1/3√v), v: volume (Verhoeven 1984). This would mean that when a dry
air in a cavity of (0.012x1x1) 0.012 cubical meters with a λ of 0.017 W/m2K would be
replaced by humid air with a λ of 0.019 W/m2K. As soon a water is created in the cavity the
conduction is multiplied by 25 (λ=0.5 W/m2K)
‐ Water causes the low‐e coating to erode. Instead of a 40‐50 years LE, this can become
shorter. Result: more heat loss. Difference in u‐value between an IGU with low‐e and without
is: 1.2 resp. 2.7 W/m2K
‐ The water in the unit enables mould and permanent water stains (figure 3). Result: less
transparent.
Critical point 3: EPDM gasket. The gasket keeps the facade air‐ and watertight, and loses the ability to
perform after 20 years. This quality loss is limited by the constant pressure of the aluminium frame
on the glass and a second gasket at the inner side of the IGU.
These Life Expectancy results will used in determining which element is will be redesigned.
3.3 Facade EoL study results
In this paragraph the current Galeria Kaufhof facade is tested through an EoL study. Information is
gained from the WTC reference study, companies involved, a study from Artzmann and
conversations with Assistant Professor Veer. It is assumed that the most common EoL method is
applied. This means that the following phases are reviewed:
EoL phase 0: ‐ assume decision taken to apply raw disassembly
EoL phase 1: ‐ assume raw disassembly process
EoL phase 2: ‐ assume complete round of cleaning and separation
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EoL phase 3: ‐ assume material and waste treatment
The objective is to select an element of the Galeria Kaufhof façade with significant DfD improvement
potential.
The EoL scenarios frameworkis specially developed for the purpose of this thesis. The main goal is to
create an overview of the EoL and directly stimulate discussion on this field of work. The basics of the
tool are presented in Figure 19 and it provides an overview of the raw‐disassembly process of the
Galeria Kaufhof facade. The shape depends on the separation methodology. The framework should
be read starting from the grey core to the outer layers. The core is the starting point (EoL phase 0)
and each layer around it represents the outcome of an EoL phase. The outcome of EoL phase 1 (the
outcome of the raw‐disassembly process) is divided over 5 categories for example.
Figure 20 shows the EoL study results for the Galeria Kaufhof façade. Only the EoL path of glass is
highlighted in this figure.
EoL phase 0: glass is still on the building
EoL phase 1: the glass group is one of the five separated from the facade.
EoL phase 2: The glass group is further treated and more materials are separarted out ofthe
group, but not all.
EoL phase 3: Glass is down‐cycled
All results will be discussed on page 37.
.
Figure 19, principle of the EoL scenario framework. It’s divided into the 3 EoL phases.
Figure 20, EoL study results of the Galeria Kaufhof façade. Orange coloured EoL path of glass starts off with a raw‐disassembly process creating a glass unit. EoL phase 2 stands for separation into the materials presented. Eol Phase 3 stands for glass which is down‐cycled.
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3.3.1 Façade EoL product: Frame (aluminium)
Aluminium is often used as a building material. Its production process requires high primary energy
demand between 145 ‐ 210 MJ/kg (steel production: 23 MJ/kg). Production contains a double stage
process that includes extraction of aluminium oxide from bauxite and the reduction to aluminium.
Specifically for the aluminium frame, the raw‐disassembly process for the Galeria Kaufhof façade is
expected to result in the following:
EoL phase 0: ‐ decision taken to apply raw disassembly
EoL phase 1: ‐ raw disassembly process, the frame is separated from the façade,
aluminium cover cap will deform and the terminating strip is unscrewed.
EoL phase 2: ‐ transport, cleaning and separation, the frame is separated from the
facade. The frame is transported to off‐site location.
Aluminium: is cut into small pieces to separate all attached gaskets. Another
separation process through magnets (to extract ferrous metals) and eddy‐currents
(to extract aluminium) is applied.
EPDM gaskets: are separated from the aluminium frame and further treated as
waste.
EoL phase 3: ‐ waste treatment, aluminium has favourable recycling properties;
process requires only 5 % of initial primary energy need for production of aluminium.
Imperfections: aluminium products appear in different alloys and mixture in oven
causes impurities (down‐cycling of product, which becomes unusable for Galeria
Kaufhof façade).
The critical point in the Galeria Kaufhof façade raw disassembly with regards to the
aluminium frame is the fact that the aluminium is currently down‐cycled.
3.3.2 Façade EoL product: Structure A steel structure beam is integrated in the façade. It transfers loads to the main load bearing
structure of the building via stainless steel screws integrated in the aluminium frame.
Specifically for the steel structure, the raw‐disassembly process for the Galeria Kaufhof façade is
expected to result in the following:
EoL phase 0: ‐ decision taken to apply raw disassembly
EoL phase 1: ‐ raw disassembly process, the structure is separated from the
façade
37
EoL phase 2: ‐ transport, cleaning and separation, steel is easily separated with
magnets. A disadvantage of the steel beams is their dimensions and weight, which
limits the transportation possibilities.
EoL phase 3: ‐ material treatment, Iron and steel are the world´s most recycled
materials. Their magnetically separation from the waste stream makes them some of
the most easily reprocessed materials. If the different steel qualities are separated
and delivered homogeneously, any grade of steel can be recycled to top quality new
metal, with no downgrading from prime to lower quality material as steel is recycled
repeatedly.
There is no critical point in the Galeria Kaufhof façade raw disassembly with regards to the steel
structure.
3.3.3 Façade EoL product: Insulated glass unit (IGU)
A major component of modern façades is the glazing. To improve their thermal properties they are
often integrated into an Insulated Glass Unit (IGU), which in the case of Galeria Kaufhof exists out of
two glass panes with non‐conductive air trapped inside by a spacer sealed to the glass.
Specifically for the IGU, the raw‐disassembly process for the Galeria Kaufhof façade is expected to
result in the following:
EoL phase 0: ‐ decision taken to apply raw disassembly
EoL phase 1: ‐ raw disassembly process, IGU is separated from the facade by using
the folding technique (breaking) or it is manually taken off with care. Manually taking
it off is most optimal for the product recovery, but most labour intensive. Typically
two grades of cullet are collected, mixed cullet and clear cullet. Clear cullet consists
of standard float glass only, whereas mixed cullet will contain a mixture of glass
types (e.g. sealed units, laminated glass, tinted glass and printed glass). The IGU is
collected in a mixed cullet container.
EoL phase 2: ‐ transport, cleaning and separation:
Glass: These separation techniques are applied (in detail see appendix C):
i. glass products are shredded into small pieces
ii. Magnet, eddy‐current, and strainer sorting techniques are applied to extract
non‐glass materials: the small glass pieces are separated to a quality that can
be used for container glass. Metals out of the mainstream are transported
for further treatment and rest materials are sent for combustion or landfill.
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Spacer: After separation brought away for waste treatment. To prevent the spacer
from being directly disposed as waste, some suppliers advertise that their spacer is
fully recyclable.
Argon gas: During disassembly used filling gasses escape out of the IGU cavity into
the atmosphere. Argon gas is used in this IGU and it safe to evaporate as it is not a
greenhouse gas.
EoL phase 3: ‐ waste treatment, glass is a material that can be melted repeatedly
without an effect on its properties, but the mixed cullet must be separated perfectly
and not be contaminated. Only a container glass manufacturer is able to apply the
mentioned separation processes (EoL phase 2). Today collected IGU cullet from
building sites in Germany are not recycled but down‐cycled, as it cannot be cleaned
sufficiently and many different types of mixed cullet are combined in one oven.
It is important to know that in the current melting process of float and container
glass uses a minimum of 30% recycled glass. For the float glass process this sounds
contrasting, because only a limited amount of single glass from the building site is
recycled. The majority is of this 30% has never reached the building site, and is
created after cutting the original jumbo pane (3.2 by 6 meters).
The critical points in the Galeria Kaufhof façade raw disassembly with regards to the IGU are:
1. Float glass is currently down‐cycled
2. The separation process in EoL phase 2 is obstructed by the way the materials within the unit
are connected with each other
3.3.4 Façade EoL product: Cladding
Specifically for cladding, the raw‐disassembly process for the Galeria Kaufhof façade is expected to
result in the following:
EoL phase 0: ‐ decision taken to apply raw disassembly or in case of reuse a
proper disassembly process
EoL phase 1: ‐ raw disassembly process, although concrete glass fibre cladding has
a reuse value (life expectancy > 2 x 20y), it is rarely reused. There is no developed
market (no buyers) in reused claddings and no temporary storage. Compared with
the other groups the cladding is taken off with care when a next life on a facade is
guaranteed.
The not more than necessary energy to take down the cladding is applied when it’s
treated as waste.
EoL phase 2: 2 scenarios are described; reuse and landfill
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‐Reuse: transport, cleaning and separation, assuming that there is a buyer for
cladding materials: the cladding elements are disassembled and treated with care.
Transport is done on pallets with the panels stacked on top of each other. After
cleaning and some small adjustments the cladding is transported to the buyer (to an
on‐site assembly or to a storage site).
The connectors are removed and the new owner will have to adapt to the previous
applied techniques to prevent visual signs of its first life in the facade.
‐ Landfill: transport and separation from connectors, directly brought to landfill
location.
EoL phase 3: ‐ material and waste treatment, two possibilities: proper reuse, or
waste treatment by directly dumping on landfills. Down‐cycling of concrete is now
and then applied in road building, but with this quantity the logistics and the storage
are a higher burden. Incineration is also not an option because of the bad burning
properties of concrete.
The critical point in the Galeria Kaufhof façade raw disassembly with regards to cladding is that there
is no buyer for the material and therefore the product belongs to waste treatment.
3.3.5 Façade EoL product: The rest group
All other materials that are part of the facade are treated here. Specifically for these materials, the
raw‐disassembly process for the Galeria Kaufhof façade is expected to result in the following:
EoL phase 0: ‐ decision taken to apply raw disassembly
EoL phase 1: ‐ raw disassembly process, all leftovers, mineral wool and the
attached films are directly separated into the waste mixture container on‐site.
EoL phase 2: ‐ transport and separation, the rest products are sorted and
separated off‐site using magnets and eddy‐current to recover metals. The gaskets
and mineral wool are combined with a main waste stream from many industries.
EoL phase 3: ‐ waste treatment, electricity is generated through incineration of
waste and ashes are dumped on landfills.
The critical point in the Galeria Kaufhof façade raw disassembly with regards to the rest group is the
fact that materials are direct waste. Only combustion provides a less environmental impact for this
group.
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3.3.6 Façade EoL critical points summary
The EoL presentation tool shows that the raw disassembly process of the Galeria Kaufhof façade
results in two material treatments (steel recycling and concrete fibreglass pane reuse) and three are
waste treatments (Combustion/landfill, aluminium and glass down‐cycling). The main waste
producer is the rest group. No method is currently applied to prevent any of these materials from
becoming directly treated by combustion.
Figure 21, Galeria Kaufhof EoL study results overview in EoL presentation tool (arrows point at critical points)
Critical point 1: Frame in EoL phase 3 results in down‐cycling of aluminium. Different types of alloys
are combined in one oven and therefore a high quality alloy cannot be guaranteed.
Critical point 2: IGU in EoL phase 2. In the IGU certain connections of different materials are difficult
to separate or even inseparable. Example is given for both cases;
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‐ The PVB‐foil will not be separated into small pieces with the standard machinery, a special
saw exist for cutting glass with PVB‐foil into small pieces.
‐ The low‐e coating is inseparable from glass in EoL phase 2 and is a minor contaminant in
phase 3. It is only solved by diluting and chemically filtering6.
Critical point 3: IGU in EoL phase 3. Glass is down‐cycled due to contamination (also due to other
types of cullet).
Critical point 4: Cladding in EoL phase 2. Reuse is possible but it rarely occurs due to a lack of buyers
and no waste treatments for a less environmental impact exist for this material than landfill.
3.4 Selected element: IGU
3.4.1 Motivation for element selection
It was decided to select the IGU element for redesign with the objective recycling. This is based on
the results of the LE and EoL study results as presented in paragraph 3.2 and 3.3.
There are several reasons to select the IGU:
1. Several critical points were found on the IGU or linked to the IGU. They are mentioned below
and presented in figure 21:
i. LE Critical point: the primary sealing has a good air tightness capacity, but is
physically weak. This influences the quality of the whole unit.
ii. EoL Critical point: PVB foil obstructs the separation process in EoL phase 2.
iii. EoL Critical point: Low‐e coating contains higher melting point elements than glass.
Only solved by diluting and chemically filtering.
iv. EoL Critical point: secondary sealing obstructs the limited separation process in EoL
phase 2 for float glass recycling.
6 Chemical filtering happens during the melting process. The coating is in amount almost negligible, but can cause imperfection in new products. Especially types like heat resistant coatings are prevented by a chemical filtering process. By adding certain materials to which the coating attaches to, it will eventually float on the surface of the melted glass and can be separated.
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Figure 22, EoL framework of the IGU
2. Out of all elements the IGU is expected to have the highest potential of improvement for a
redesign for DfD.
3. When expressing the impact in weight, the waste of the IGU is ranked highest;
IGU: 61%
Rest group (mineral wool): 12%
Aluminium frame: 10%
Steel construction: 9%
GFRC cladding: 6%
Of the Galeria Kaufhof facade 91% is treated as waste and 67% of whole facade waste (140
tons) can be reduced by redesigning the IGU.
3.4.2 Background information on IGU
The IGU is a combination of multiple materials and connected in the whole facade via the frame through gaskets.
Since the first IGU was introduced in the 80‐ties, many developments have been made in its design.
New alternatives have been introduced since the Galeria Kaufhof IGU was designed and installed.
It is important to understand what currently available techniques exist when starting on the redesign
process. For the purpose of creating that understanding please find below an overview of the IGU
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development over time. It also shows EoL scenarios and the unit’s thermal performance level (figure
on the next page(s)).
IGU development over time Legend: ‐ EoL scenario indication (right) ‐ Heat loss per unit in W/M2K
Step 1: Single glass pane This was simply a glass pane with little insulation. Heat loss: 5 W/m2K EoL scenario: reuse
Step 2: The first IGU The first IGU was constructed by attaching two panes to each other. Both laminated glass panes are heated on their edge over their softening point and attached to each other. Disadvantages: the same glass must be used because of different heating and bending behaviour – coated and laminated glass cannot be used due to the high temperatures during production. Heat loss: 3 W/m2K EoL scenario: recycling
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Step 3: Glass‐metal‐combined Both panes are welded together with a lead web. Heat loss: 3 W/m2K EoL scenario: down‐cycling (high)
Step 4: Metal spacer Currently the most common process. The spacer is a hollow profile of steel or aluminium. The profile is filled with drying means to de‐moisten locked up air in the unit. Heat loss: 3 W/m2K EoL scenario: down‐cycling (high)
Step 5: Argon gas + sealings The spacer is now provided with a narrow butyl rope for sealing both sides, which are facing the glass panes. Butyl does not have a strong adhesive force, but is effective against water steam. When both panes are pressed together with the butyl, the pane gabs are filled with a gas for improvement of sound and/or heat insulation. The most common filling gas is Argon, which has low heat conductivity. In the last step, the unit is provided with a second sealant all around for the needed tensile strength between the panes. The most common sealant is produced on basis of polysulfide, polyurethane or silicon. Polysulfide has the best properties regarding their sealing effect and ageing properties. The advantages of silicon are its high mechanical resistance as well as the resistance against UV‐radiation. Heat loss: 2.7 W/m2K EoL scenario: down‐cycling (high)
Step 6: Low‐e coating (Galeria Kaufhof IGU) Low‐e coatings: improves the thermal insulation by having a low emissivity to outside and reflects infra red light to inside. There are three ways of implementing the coating to the IGU. Hard coating, soft coating, or coating on a suspended film (not attached to the panes). Heat loss: 1.2 W/m2K EoL scenario: down‐cycling
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Step 7: Warm spacer A different attempt forms the basis for joining with thermo‐plastic spacer. In this case, the metallic spacer is completely replaced by a two‐stage organic sealant system (warm edge technology). The inner sealing is made on a basis of butyl and represents the seal against gas loss and humidity. Added with this are drying means for absorption of humidity. The second, outer sealing, is a conventional insulating glass sealant. Heat loss: 1 W/m2K EoL scenario: down‐cycling
Step 8: Triple pane To improve the thermal insulation level a second cavity is introduced. The pane in between can also be replaced by a foil (reference study Empire State Building) Heat loss: 0.8 W/m2K EoL scenario: down‐cycling
Step 9: Vacuum The vacuum in between the panes is introduced to further reduce heat loss and sound. This has reduced the size of the cavity Heat loss: 0.5 W/m2K EoL scenario: down‐cycling (low)
Figure 23, Development of IGU over time. Figure is designed by writer of this thesis to combine the information from two sources: Hall (2008) and Brockmann (2002)
It can be concluded that over time the IGU has become more complex. The additional layers have
gained importance by decreasing the heat loss significantly and according to Veer charge the
majority costs of the IGU (float glass 5‐8% of entirety). As the quality increased over time the EoL
scenario has become worse, but this can be seen a driver to improve the design with DfD. This will be
done in chapter 4.
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4 Redesign
4.1 Redesign Plan
In this paragraph the redesign plan is discussed. It was decided that a redesign of the IGU is to be
made at a concept level leaving the final details to be designed by the manufacturer who creates a
detailed executable design
As a first step in the redesign process of the IGU, the DfD objective is determined. As a second step in
the redesign process of the IGU, the DfD strategies are determined based on the selected objective in
the first step.
The redesign process is iterative, which is why validations are done continuously throughout the
process. When two final designs are created both alternatives are assessed compared to the existing
IGU design.
Over time multiple designs on the IGU have been made and many designs have been produced. It
may be concluded that in the changes in time have decreased the heat loss of the element (which is
positive), but it has also caused the EoL scenario to have a larger impact on the environment (which
is negative).
In the more or less 30 years that the IGU now exists it developed to high performance unit. Before
starting the redesign process it is wise to scan the current available techniques developed over the
years. This motivated a distinction between Redesign A and B;
Redesign A uses available techniques and creates a redesign by combining existing concepts. The
main advantage is that assembly techniques are currently available and that it is therefore directly
applicable without further development.
Redesign B represents an ‘out of the box’ concept. It is based on the DfD objective and its strategies,
and on new IGU concepts.
4.2 DfD Objective & Strategies
4.2.1 DfD Objective As a first step in the redesign process of the IGU, the DfD objective is determined. Should the IGU be
designed for disassembly with the objective to i) adapt the element to continue its service life, or ii)
to reuse the element in another façade, or iii) to reuse the different materials in the element in
different functions, or iv) to recycle the different materials in the element?
Currently the IGU is designed for assembly to perform. The different options according to the DfD
objectives are discussed on the next page and a selection is motivated:
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DfD with the objective to adapt the IGU to continue its service life:
In practice, for the IGU this objective would require the element to be taken out of the aluminium
frame. To bring the IGU back to its original state would require an off‐site procedure based on the
currently available techniques. Certain old materials would need be replaced, before the element is
taken back to the location and reinstalled.
The reference study of the Empire State Building is an example of DfD with the objective of
adaptation. The old IGU (that was fitted with a special float glass type and metal spacer) was
relatively easy to separate. Also a special assembly setting was realised on‐site.
Redesigning the IGU with the objective to adapt the IGU to continue its service life should focus on:
‐ low energy usage by creating an on‐site (dis)assembly procedure
‐Easy accessibility of the to be replaceable elements
DfD with the objective to reuse the IGU as an element in a next service life:
In order to be reused as an IGU in a next service life, this objective would require markets to accept
standards for this element. Facade designers and architects currently do not work with standardised
sizes for the IGU. Additionally, the life expectancy would need to be extended by the constructor as
currently the life expectancy of the element as a whole is approximately 20 years.
After 20 years the unit decreases in air tightness and air containing moisture enters the cavity, which
rapidly decreases the thermal and technical quality of the unit. Therefore upgrading the IGU after its
first service life with the intent of reusing it would require removing all attached materials which
makes the process similar to reuse on material level.
Redesigning the IGU with the objective to reuse the IGU as an element in a next service life should
therefore focus on:
‐extending the lifespan so that a second life is possible; minimum of 40 years.
‐integrating design steps for architects that stimulate the use of already existing units
DfD with the objective to reuse the IGU materials in a next service life:
If the materials of the IGU are reused in a next service life, the IGU would first be removed from the
facade as a whole element and it would then be taken apart off‐site.
Disadvantages on the current design would include the following:
There is high risk of down grading the materials (a little scratch in the 13 mm outer edge has
reduces the physical performance for a next service life on a façade (Veer 2011)).
Glass is the only material with a long life expectancy capable for reuse.
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The float glass panes are relatively cheap and therefore not financially interesting to have a
labour intensive treatment for reuse.
Redesigning the IGU with the objective to reuse the IGU’s materials in a next service life of a different
IGU should therefore focus on removing the above disadvantages.
DfD with the objective to recycle the IGU materials after the IGU’s service life:
If the materials of the IGU are recycled after the IGU’s service life, the IGU would first be removed
from the façade as a whole element and it would then be taken apart off‐site. There is no longer
expected lifespan of the glass and therefore the raw‐disassembly can be done in such way that it
doesn’t obstruct the separation process in the EoL phase 2. The standard procedure applied by both
types of glass manufactures is normally starting off with breaking the cullet into small pieces to
optimise treatment. The cullet for example has to able to enter the oven and have a certain size for
the limited dimension of the opening.
The main problem of this objective in the current design is that several materials are inseparable. For
this reason, down‐cycling is often achieved rather than recycling.
Redesigning the IGU with the objective to recycle the IGU materials after the IGU’s service life should
therefore focus on avoiding down‐cycling.
Selected DfD Objective
To visualise and grade the differences in environmental impact, the waste and embodied energy are
combined in the figure above. The embodied energy is added as a virtual weight onto the existing
Waste created
in tons
Total
environmen
tal
impact in tons
On‐site
disassembly
tools
Transport
Off‐site
disassembly
tools
Cleaning
methods
Melting process
Down‐cycling (current design) 86 + + + + + 86 + 5
Recycling glass unit materials 0 + + + + + + 5
Reuse glass unit materials 0 + + + + 0 + 4
Reuse glass unit product 0 + + 0 + 0 + 3
Adaptation 0 + 0 0 + 0 + 2
Figure 24, Environmental impact for every DfD objective. Virtual waste is added to visualize and grade the impact.
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waste weight. For every ‘+’ 1 ton in weight is added. In chapter 2 is explained that calculating the
embodied energy is difficult task due to many relations with all the ongoing processes in the EoL.
Though in figure 24 a scheme is developed for this thesis to grade the environmental impact, and the
first conclusion is that the objective Adaptation has a minimal impact of 2 tons.
In theory DfD objectives can be combined to optimise the possibilities of the element after its service
life. One could design the element for Adaptation and Reuse at the same time. It was decided for the
purpose of this thesis, to work with only one objective during the redesign of the IGU.
The selected objective is recycling. The main reason for this is that there is high potential for
decreasing the impact on the environment. This can be achieved when down‐cycling is avoided and
only recycling achieved. The adaptation objective also has potential, but it requires an onsite (dis)‐
assembly technology which goes beyond the extent of this thesis. Additionally, recycling may be
viewed as the lowest in hierarchy considering the environmental impact, but it has a very important
position as the IGU designed for adaptation or reuse also needs to be recycled (after several service
lives).
4.2.2 DfD Strategies
As a second step in the redesign process of the IGU, the DfD strategies are determined based on the
selected objective in the first step.
The DfD strategy list of Crowther is used to select the strategies. He is the only scientist that has
created a list by ranking the strategies with different objectives. This also explains why his list is used
here. In 2.3.2 and in appendix A one can find his full list of design strategies. Crowther highlights
seven design strategies which according to him are ‘highly relevant’ when designing with the
objective to recycle materials after their service life. These are presented in Figure 25
1. Use recycling and recyclable materials to allow for all levels of the recycling hierarchy, increased use of recycled materials will also encourage industry and government to develop new technologies for recycling, and to create larger support networks and markets for future recycling. 2. Minimise the number of types of materials this will simplify the process of sorting during disassembly, and reduce transport to different recycling locations, and result in greater quantities of each material. 3. Avoid toxic and hazardous material this will reduce the potential for contaminating materials that are being sorted for recycling, and will reduce the potential for health risks that might otherwise discourage disassembly. 4. Avoid composite materials and make inseparable products from the same material In this way large amounts of one material will not be contaminated by a small amount of a foreign material that cannot be easily separated. 5. Avoid secondary finishes to materials such coatings may contaminate the base material and make recycling difficult, where possible use materials that provide their own suitable finish or use mechanically separable finishes. 6. Provide standard and permanent identification of material types many materials such as plastics are not easily identifiable and should be provided with a non‐removable and non‐contaminating identification mark to allow for future sorting, such a mark could provide information on material type, place and time or origin, structural capacity, toxic content, etc. 24. Use light weight materials and components this will make handling easier and quicker, making disassembly and reuse a more attractive option. This will also allow disassembly for regular maintenance and replacement of parts.
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The following four strategies are found to be most important when redesigning the IGU with the
objective of recycling its materials after the IGU’s service life. These strategies are used as a basis for
the redesign of the IGU; number 1, 2, 4 and 5
Note that the below strategies are not explicitly used:
3. There are no hazardous materials integrated into the IGU, neither within the available
techniques
6. Identification on glass is not needed considering the limited amount of glass manufacturers
in the region (7 in the world). If it will be required in the future information can be easily
added on the side or through a chip in the cavity
24. Glass forms the majority of the weight of the IGU, and this material will not be replaced.
Replacement of the spacer with a lighter material has minor impact.
Figure 25, Crowther’s seven highly relevant design strategies with the objective of recycling. Full list is found in
the appendix A.
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4.3 Redesign A
Redesign A is created based on existing IGU concepts with the objective of improving it for recycling
purposes. The design strategies are used as a driver to upgrade the current IGU design as used in
Galeria Kaufhof (as presented in paragraph 3.1).
The available techniques that are combined to realise final redesign A are presented in figure 26.
DfD Strategies Available IGU techniques Concept
1.Use recycling and recyclable materials
a. Glass spacer
2.Minimise the number of types of materials
b. The vacuum IGU
4.Avoid composite materials c. ’warm edge’ spacer
5.Avoid secondary finishes
d. 10mm pane
e. foil in cavity
Figure 26, Existing IGU concepts driven by different DfD strategies
In the next step the different available techniques are compared with the IGU used in Galeria Kaufhof at three different levels: design properties, heat loss properties and through an EoL test. The results are presented in figure 27.
The following conclusions can be drawn:
1. All presented techniques are slightly different to the IGU applied in Galeria Kaufhof as
indicated in the second column in figure 27, except the aluminium spacer.
2. The heat loss test shows that the vacuum IGU concept has a better heat loss value than the
IGU in Galeria Kaufhof (0.5 vs. 1.2 W/M2K). The glass spacer concept has a heat loss value
which is worse than the IGU in Galeria Kaufhof (3.0 vs. 1.2 W/M2K).
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3. The EoL test shows that only the vacuum IGU scores worse than the IGU in Galeria Kaufhof.
The glass spacer concept scores better: it only requires a minimum treatment in EoL phase 2.
The warm edge spacer, the 10mm pane and the foil in cavity concepts score better, they
simplify the process of maximum treatment in EoL phase 2.
Available techniques Δ current IGU Heat loss(W/M2K)
Δ LE test Δ EoL test
a. Glass spacer
Excl: 1st‐ & 2nd sealing,Aluminium spacer, and desiccant Add: glass spacer
3.0 ‐ ++
b. The vacuum IGU
Excl: 1st‐ & 2nd sealing,Aluminium spacer, and desiccant. Add: small glass spacers and metal foil
0.5 + ‐
c. ’warm edge’ spacer
Excl: aluminium spacer and desiccant. Add: thermo‐plastic spacer
1.0 0 +
d. 10mm pane
Excl: PVB‐foil and two 6 mm panes Add: one 10 mm pane of toughened glass
1.2 0 +
e. foil in cavity Excl: low‐e coating on glass Add: foil creating 2 cavities with low‐e coating
0.8 0 +
Figure 27, Differences between existing IGU concepts and the Galeria Kaufhof IGU, incl a heat loss, LE and EoL test
Final redesign A:
By combining the techniques that improve the heat loss value and the EoL test results a final redesign
A is created. The warm edge spacer, 12 (2x6) mm pane and foil in cavity concepts are combined in
final redesign A. Eventually two of the five available techniques are used to create redesign A. For
every eliminated technique a short description is presented:
a. Including the glass spacer would exclude the integration of argon gas and low‐e
coating. Resulting in a unit with a lower thermal performance.
b. The negative EoL test made it clear to not further see this technique as an option.
d. Due to regulations in Germany this technique is eliminated. The integration of PVB
foil in the IGU is also known as safety glass, it reduces the chance of harming a human
when the unit breaks.
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Figure 28 shows the concept of final redesign A and drawings can be found in appendix D.
Figure 28, final redesign A
The following conclusions can be drawn on final redesign A:
Advantages: Disadvantages:
No secondary finishes on glass
No material with a higher melting point is integrated in the IGU
Less heat loss (0.8 W/M2K)
No toxic materials
The secondary sealing obstructs the separation process. Maximum treatment can only be used on this IGU
More expensive due to thicker inner pane
No recyclable materials used except glass
This final redesign A will be further assessed in paragraph 4.6.
4.4 Redesign B
Redesign B represents an ‘out of the box’ concept. It is based on the DfD objective and its strategies,
and on new IGU concepts.
The objective is to improve its EoL for recycling purposes. Redesign B1 is created by adjusting the
current Galeria Kaufhof IGU design using the following DfD strategies: use recycling materials,
minimise the number of types of materials, avoid composite and inseparable materials and avoid
secondary finishes.
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Redesign B1 consists out of two clean glass panes with an integrated element in the middle. This middle element is taking over the task of spacer creating the cavity in the current design. It’s an airtight element with trapped argon gas inside with the necessary width to thermally function optimal. In this stage it is seen as a vulnerable element weak for outer influences, such as force impacts. Redesign B1 shows good results in the EoL test as it only requires a minimum treatment in phase 2. The performance of Redesign B1 is less than the Galeria Kaufhof IGU and so is the assembly complexity. This redesign requires 3 or more steps to (dis)assemble the unit from the façade. The results are summarized in figure 29:
Redesign B1 Concept Δ current IGU EoL test Assembly complexity
Performance
‐ Created based on DfD strategies ‐ Two clean panes, with an integrated (weak) element in the middle
Excl: PVB foil coating on glass + ‐ ‐
Figure 29, Redesign B1: concept, differences with Galeria Kaufhof IGU, and test results
Redesign B2 is a concept that aims to improve Redesign B1 on performance. By integrating the EPDM gasket in the redesign the physical performance will come on the same level as the current IGU. Redesign B2 shows good results in the EoL test as it only requires a minimum treatment in phase 2. The performance of Redesign B2 is better than Redesign B1 and equal to the Galeria Kaufhof IGU. The assembly complexity in this redesign still requires 3 or more steps to (dis)assemble the unit from the façade. This is what needs to be improved in a next step. The results are summarized in figure 30:
Redesign B3 is a concept that aims to improve Redesign B2 on assembly complexity. By integrating the EPDM the unit can be assembled as one on‐site. Redesign B3 shows good results in the EoL test as it only requires a minimum treatment in phase 2. The performance of Redesign B3 is equal to Redesign B2 and equal to the Galeria Kaufhof IGU. The assembly complexity in this redesign has however improved. Redesign B3, due to the vacuum principle, requires 2 steps to (dis)‐assemble the unit from the façade. The results are summarized in figure 31:
Redesign B2 Concept Δ current IGU EoL test Assembly complexity
Performance
‐ Redesign B1 + Performance Upgrade ‐ EPDM gasket integrated creating a unit of 3 elements to optimise integration in facade
Add: EPDM gasket + ‐ =
Figure 30, Redesign B2: concept, differences with Galeria Kaufhof IGU, and test results
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Redesign B3 Concept Δ current IGU EoL test Assembly complexity
Performance
‐ Redesign B2 + Assembly Upgrade ‐ Additional to previous concept is a technique making the assembly as well as the disassembly process significantly easier
Add: vacuum (dis)‐ assembly technique
+ + =
Figure 31, Redesign B3: concept, differences with Galeria Kaufhof IGU, and test results
Final redesign B3 (details):
The main idea of this redesign is that the additional layers must be attached to the glass in such way
that they are easily removable. Other options exist such as glue that dissolves itself when held in
warm water or a foil that is simply pulled off by hands. In the research of this redesign process the
vacuum turns out to be best fulfilling an easy EoL with a rapid and at the same time careful
disassembly.
Figure 32 shows the detailed concept of final Redesign B3 and drawings can be found in appendix D.
Figure 32, the concept of final Redesign B3 Redesign B3
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The following conclusions can be drawn on final redesign B:
Advantages: Disadvantages:
100% plain glass
Glass protection layer integrated
More integrated into the facade
Easy disassembly process
Damage to foil will also damage total unit
Complex assembly process
Application on a glass facade without aluminium frame is not possible
4.5 Assessment
The current Galeria Kaufhof IGU design is compared to Redesigns A and B3 by means of an
assessment. The main objective of the Redesigns was to design with the objective of recycling to
decrease the waste impact on the environment.
The criteria by which a comparison is made are listed below (incl. results):
1. Design strategies: With how many strategies is the designs created?
Current: 0
Redesign A: 2,
Avoid secondary finishes: low‐e coating on foil instead of on glass
Avoid composite materials and make inseparable products from the same
material: Thermal plastic spacer with desiccant.
Redesign B3: 3,
Avoid secondary finishes: low‐e coating on foil and no PVB foil
Avoid composite materials and make inseparable products from the same
material: Thermal plastic spacer with desiccant.
Minimise the number of types of materials: eliminated two sealings, PVB foil
and aluminium spacer. Added are foils.
2. Life Expectancy study results: which design has the highest life expectancy?
Current: 20 years (at least), based on literature.
Redesign A: 20 years (at least), based on literature.
Redesign B3: Less than 20 years, estimation is 10 years. There are two weak points in this
design that causes it to fail before the average of 20 years;
‐ the closure of the vacuum chamber.
‐ the foils with a limited air tightness over time.
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3. EoL study results: in the EoL which design has the best disassembly scenario (with the least
waste creation and environmental impact)?
The redesign must pass the EoL test (please see EoL theory in 2.1.2):
i. EoL phase 0: ‐ assume decision taken to recycle materials
ii. EoL phase 1: ‐ assume raw disassembly process
iii. EoL phase 2*: ‐ can the IGU be transported in a separate container?
(no: combustion/ landfill)
‐ is cullet clean after minimum treatment? (yes: recycling)
‐ is cullet clean after maximum treatment? (no: down‐cycling)
iv. EoL phase 3: ‐ does mixed cullet melt below 1600 degrees Celsius?
(no: low grade of down‐cycling)
* Float glass and container glass recycling are two different recycling methods. Float glass
recycling brings back the IGU glass to the same quality level and is therefore preferred. The
distinction between the two methods is made to reward float glass recycling that only
requires a minimum treatment.
Current: down‐cycling, fail in EoL phase 2 and 3 (figure 22).
86 tons of waste will be created at the EoL and 5 virtual tons of
environmental impact.
Redesign A: down‐cycling, fail in EoL phase 2. (figure 33)
86 tons of waste will be created at the EoL and 5 virtual tons of
environmental impact.
Redesign B3: Recycling, due to the plain panes minimum treatment is needed. (figure 34)
Only 5 virtual tons of environmental impact is added to the weight.
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Figure 33, EoL framework of the redesign A of the IGU. This shape is different compared with the previous presented framework; the starting point is in EoL phase 1 and the separation process divides the unit into 4 groups.
Figure 34, EoL framework of the redesign B of the IGU. This shape is different compared with the previous presented frameworks; the starting point is in EoL phase 1 and the separation process divides the unit into 3 groups.
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4. Performance: which design can transfer the forces the best? And, which design has the least
heat loss?
Physical performance:
Redesigns have to be able to bear all expected forces and all loads have to be able to be
transferred to the aluminium frame, by:
i. Precautionary measure in case the glass breaks
ii. Sufficient dimensions of the glass panes
iii. Frame attaches on a minimum of 13 mm from the outer edge on the glass surface
Thermal performance:
i. Heat loss in W/m2k
Current: Thermal: 1.2, Physical: fulfils all requirements
Redesign A: Thermal: 0.8, Physical: fulfils all requirements
Redesign B3: Thermal: 1.3‐1.5. By adding the EPDM with a higher conductivity than air, 0.2
instead of 0.017 W/m2K, the thermal performance reduces (see for more
information appendix F)
Physical: ii, by integrating a thicker pane (10mm) of toughened glass
surrounded by a foil it is designed to prevent glass falling down the building.
This must be further developed and tested to give a 100% guarantee of this
capability.
5. Costs: which design is the cheapest? Glass takes 5‐8% of the total unit costs and therefore
additional materials and the assembly techniques indicate the total costs.
The redesigns are designed to be assembled using currently available assembly tools and
methods. There is a distinction made between on‐site and off‐site assembly and the higher
the complexity of the assembly process is, the more it will cost. The assembly complexity for
each redesign will be presented.
The production process of the elements of the IGU is not taken into account, and for
redesign A & B only the main difference will be explained.
Current: Off‐site
Step 1 surrounding: special hermetic room with clean air and tools
Step 2 pane edges: the edges of the panes are cleaned from low‐e coating
with a special polishing machine.
Step 3 drying: with the sputter technique the surface of the panes are dried.
It is fast compared with the standard/old procedure (4 hours) which has a
chance on damaging the coating.
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Step 4 spacer attachment: with primary sealing the aluminium spacer is
attached to the pane.
Step 5 gas filling: argon gas is added to the airtight space between the panes.
With a thin tube thought the primary sealing or a hole in the spacer sealed
after filling.
Step 6 sealing: final (secondary) sealing creating one unit by structurally
holding the panes together.
On‐site:
One element
Redesign A: Off‐site
Main difference between the current design and the redesign A assembly is
the integration of the foil. Step 4 has a complex integration method of
stretching the foil while heating and without damaging the low‐e coating.
According to Veer this technique has cost efficiency issues and hasn’t been
able to solve them since its existence (15 years ago).
On‐site:
One element
Redesign B3: Off‐site
Main difference between the current design and the redesign B assembly is
the vacuum technique by use of foils. This process skips step 2, but needs a
special vacuum chamber to fulfil step 4; where the glass is attached to the
extended spacer by creating vacuum between the glass and the foils. There is
an enormous amount of energy used to create vacuum in the chamber and
the dimensions of the unit are limited to the size of the chamber.
On‐site:
One element
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Presented below in Figure 35 are the assessment findings:
Figure 35, Assessment results in ‘+’ and in ‘‐‘ compared with the current design.
Based on the above criteria the assessment shows that Redesign A is the better alternative
considering the current techniques on performance. Redesign B must be further developed because
of its positive EoL scenario potential.
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5 Conclusions and Recommendations
This thesis has shown the application of DfD on an element of a commercial façade, with the
objective to decrease waste. Many choices had to be made during this thesis. This chapter gives an
overview of the decisions taken and concludes whether the goal of the thesis is met, the learnings,
what could be improved and recommendations for future studies.
The selected façade for this research was the Galeria Kaufhof façade in Frankfurt am Main, because
this façade fulfilled all boundary conditions. Next step was to focus on a certain element of this
façade. The choice was between the structure, cladding, frame, glass unit and rest group. The
decision was made by using results of the LE study of the façade, to find the weakest link, and by
using the EoL study, to find the element with the highest potential to decrease waste.
The life‐expectancy study showed that the primary sealing, between the glass and aluminium, keeps
the glass unit airtight. The sealing is one of the weakest links ‐ it is vulnerable for UV‐radiation and
has a limited elastic capability when heat expansion of glass occurs.
The EoL results showed 2 critical points related to the IGU: the IGU is currently down‐cycled due to the inseparable materials used within the IGU, and due to the integration into the container glass
recycling process.
Also the float glass of the IGU accounted for 61% of total waste of the façade, which all together
concluded the IGU to be the selected element.
The following step was to determine the DfD objective and strategies for the IGU. The choices
between objectives were: to design for adaptation, to reuse or to recycling. Since adaptation and
reuse of the IGU/glass are not so common and quite complex, recycling has the highest potential for
decreasing waste.
The most important strategies for DfD of the IGU were selected from a long list. The 4 strategies
chosen are: Use recycling materials, minimise the number of materials, avoid composite and
inseparable materials and avoid secondary finishes. With these strategies, the redesigns of the
current IGU of the Galerie Kaufhof façade have been developed.
Redesign A focused on existing IGU concepts and is designed without aluminium spacer and the
coating on glass, and has a better thermal performance than the current IGU. However, because the
secondary sealing is still between the 2 plain glass panes and the PVB foil is still a secondary finish on
the glass, it is not feasible to have it recycled as float glass. This redesign will be down‐cycled to
container glass, which is similar to the current IGU down‐cycling, with less contamination due to the
elimination of the low‐e coating.
Redesign B is a more “out of the box” design with new concepts. It does not contain the aluminium
spacer nor any secondary finishing and can thus be recycled as float glass. The total waste in kg of
the facade will be reduced by 61%. The downside of this design is that its life ends potentially sooner
than the current IGU.
My overall conclusion of this thesis is that applying DfD on a commercial façade requires specific
focus on an element, and needs clear objectives before entering the design phase. The EoL
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framework is essential in the design process by creating good discussion circumstances. This
improved the IGU redesigns of the current IGU, one through thermal performance, and the other
through recycling. The total facade waste can be reduced with 61%, however material improvements
are required for redesign B to meet the life expectance of 20 years.
During this thesis I have learned more on DfD in façade design and the recycling of glass, which
should be taken into account for future research.
Façade selection:
The façade chosen was an on‐site system. Currently on‐site built facades are common for
refurbishments, but the development in the past tells us that the off‐site system will increase
in number. It’s recommended to focus on the off‐site system when integrating DfD into
facade design, this will increase the accuracy of the disassembly process.
Element selection:
The rest group has high priority for EoL improvement. This is a waste producer and no near
future improvements are detected. Material specialists have to invent material treatments
for this group or designers must consider the usage of other materials with recycling
capacities.
The IGU with its current techniques has an optimal performance and glass is too cheap to
prevent waste. Other factors will have to stimulate waste prevention such as regulations and
limited energy consumption.
DfD objective and strategies:
The DfD objectives adaptation and reuse have potential for further research. Especially
adaptation must get future attention. Within the IGU, float glass has not developed for
decades, the additional layers in the past, and will in the future give the IGU better
performance capabilities. Further research on these layers, must secure easy removal and
assembly to achieve the DfD adaptation objective. In figure 37 is an example presented of a
burglar resistant foil, easy assembly and fully transparent.
A new glass type must be created to reduce waste. In general two glass types exist; container
and float glass. Float glass is only used in the facade industry because it demands high
quality, but this can be reconsidered. There are parts in the facade where a less transparent
glass can be used as shown in the figure on the next page. The new float glass is created by
glass collected and cleaned by the container glass manufacturer and is allowed to be
contaminated. This is not an all‐embracing solution, but it can reduce current 61% glass
waste weight. Some suggestions for further study:
Find the percentage of potential recycled float glass usage in the facade industry.
The cooperation between the two glass types manufactures; there will be a
separation and cleaning process at the container glass manufacture and the
production process will be done with float glass machinery.
Methodology to integrate this in the design process for architects
64
Figure 36, a sketch of the possible application of a new float glass type. On top the standard glass is positioned and at the bottom recycled glass is in such way placed that field of vision and the incoming light is not blocked.
Recommendations for the redesigns:
Recycling of float glass out of the IGU is very challenging and might be a more long‐term
objective; Plain glass is required for float glass recycling and additional layers are needed to
fulfil the high‐level performance. These layers have been indispensable for the IGU quality in
the past and current, and this will be a challenge for future variants.
It is recommended to further study possibilities to integrate plain glass. Further specific study
within other industries could bring valuable solutions to replace secondary finishes. The
industry of nature brings an interesting example of the butterfly wing (figure 37). This one
material pane has a high physical performance and a certain level of transparency; could this
be the next step in the IGU development?
65
Also, I would like to share some more general recommendations from my literature study:
Assembly. When designing for disassembly one must always consider the assembly
techniques, how should the facade be disassembled without considering how it’s put
together? Further study should focus on creating an overview on the current existing
assembly techniques that suit the disassembly. It has great value to be able to recommend
the manufactures which assembly method should be reconsidered or promoted for future
expected regulations stimulating DfD.
Other industries. The example of the car industry has proven that other industries have a
higher level of DfD integration in their design process. The façade industry can learn from
these industries. Several scientists have done research in this field of work, but never with a
façade focus only. One recommendation is to create a DfD strategy list only for facades,
second is the method of integrating DfD strategies in the design process.
Information system. There are many ways of disassembling the many types of facades. To
guide this process, a clear information system must be applied to inform the right execution
method 20 years after assembly. The decision in the WTC Amsterdam project to reassign
Figure 37, left, assembly of transparent burglar resistant foil. It can be bought in a regular building material shop for amateurs (Gamma). On the right a butterfly presenting a possible future perspective on the IGU. With the transparency and physical properties similar to the butterfly wing a one material IGU is ideal for recycling.
66
Scheldebouw encouraged the quality of work, and an efficient solution could be applied
because of the pre‐knowledge on the facade. A potential information system is the BIM
(Building Information Model) explained in 2.3.1. It should be integrated into the facade
design, but also the whole building industry to stimulate less waste by preventing mistakes.
DfD to reduce energy consumption. The reference study of the Empire State building shows
a high level of energy efficiency in combination with reuse of glass panes. In this thesis a
focus is on the waste reduction, but the worldwide energy consumption also has a major
impact on the environment. Further research should calculate the energy reduction DfD
brings. It will be difficult to estimate the energy flow in accuracy, because the number of
material lifecycles results in a contrasting outcome. For example, increase energy input in the
disassembly phase will make the output decrease in later stages.
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Table of Figures
Figure 1, Average building lifespans (left) and building layers lifespans (right) (Brand 1994, Crowther
2001, Yeang 2008) ................................................................................................................................. 10
Figure 2, Swiss roll waste management (Woon/Energie1991) ............................................................. 10
Figure 3: Insulated glass unit failure of the building EnBW in Stuttgart Germany. Water has come
inside this decreased the thermal and visual performance. (Ebbert 2010) .......................................... 14
Figure 4, from left to right, demolition of the burned down architecture faculty in Delft with a
wrecking ball (Sanoma Digital Group 2008). 122 Leadenhall street in London halfway a raw
disassembly process (Rasmus Broennum architects 2009). Vodafone Hoghhaus also known as
Mannesmann tower is properly disassembled. The exchange of the 1950s façade with new units, as
seen above (RKW 2009). ....................................................................................................................... 16
Figure 5, Separation criteria and techniques. (Hendricks 1999) .......................................................... 17
Figure 6, Three DfD examples. Left: The temporary building of the faculty of architecture Delft after
the main building burnt down (tudelft). Middle: Elegant joint of the travelling pavilion of IBM by
Renzo Piano. Right: Ideal scenario for DfD in the facade industry – Façade is disassembled on the
same way it’s assembled. New upgraded façade with the same outer appearance on top, old façade
is disassembled with the same crane (RKW 2009). ............................................................................... 21
Figure 7, coating is added onto the glass by a liquid spray. This is a secondary finish on the glass
surface and must be prevented (Hall 2008). ......................................................................................... 23
Figure 8, Strategy list for DfD made by Crowther (2005). This list distinguishes itself from other DfD
lists by ranking the strategies on the DfD objectives. By using this list during the design process, the
designer can focus better on the objective, and thereby enlarge the chance for a successful
disassembly. .......................................................................................................................................... 24
Figure 9, WTC Amsterdam: parties involved in the refurbishment ...................................................... 25
Figure 10, from left to right: assembly process of old facade in 1985. Internal view on façade (right):
one of the refurbishment requirements was to enlarge the glass surface for more daylight. ............. 26
Figure 11, vertical section of refurbished facade with new elements. Critical point: connection of
sandwich panel with load bearing facade structure. ............................................................................ 26
Figure 12, Office XX building in Delft. Picture taken in 1999. ............................................................... 27
Figure 13, BELCATO model: Building End of Life Analysis ..................................................................... 28
Figure 14, Old (left) and new (middle) glass unit, and the Empire State Building, NYC (right). ............ 28
Figure 16, horizontal section Galeria Kaufhof façade. The red lines point out elements added in 2008,
stone wall is part of the original part of the façade. Schale 1:10, see appendix B for 1:5 drawings .... 31
Figure 15, old façade (left) and new façade built in 2008. ((right) ........................................................ 31
Figure 18, Galeria Kaufhof Façade Life expectancy study results. Source: IEMB list (2008). ................ 32
Figure 17, Galeria Kaufhof Façade LE study results visualized on a horizontal section of the façade.
Scale 1:10, see appendix B for 1:5 drawings ......................................................................................... 32
Figure 19, principle of the EoL scenario framework. It’s divided into the 3 EoL phases....................... 34
Figure 20, EoL study results of the Galeria Kaufhof façade. Orange coloured EoL path of glass starts
off with a raw‐disassembly process creating a glass unit. EoL phase 2 stands for separation into the
materials presented. Eol Phase 3 stands for glass which is down‐cycled. ............................................ 35
Figure 21, Galeria Kaufhof EoL study results overview in EoL presentation tool (arrows point at critical
points) .................................................................................................................................................... 40
Figure 22, EoL framework of the IGU ................................................................................................... 42
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Figure 23, Development of IGU over time. Figure is designed by writer of this thesis to combine the
information from two sources: Hall (2008) and Brockmann (2002) ..................................................... 45
Figure 24, Environmental impact for every DfD objective. Virtual waste is added to visualize and
grade the impact. .................................................................................................................................. 48
Figure 25, Crowther’s seven highly relevant design strategies with the objective of recycling. Full list
is found in the appendix A. .................................................................................................................... 50
Figure 26, Existing IGU concepts driven by different DfD strategies .................................................... 51
Figure 27, Differences between existing IGU concepts and the Galeria Kaufhof IGU, incl a heat loss, LE
and EoL test ........................................................................................................................................... 52
Figure 28, final redesign A ..................................................................................................................... 53
Figure 29, Redesign B1: concept, differences with Galeria Kaufhof IGU, and test results ................... 54
Figure 30, Redesign B2: concept, differences with Galeria Kaufhof IGU, and test results ................... 54
Figure 31, Redesign B3: concept, differences with Galeria Kaufhof IGU, and test results ................... 55
Figure 32, the concept of final Redesign B3 Redesign B3 ..................................................................... 55
Figure 33, EoL framework of the redesign A of the IGU. This shape is different compared with the
previous presented framework; the starting point is in EoL phase 1 and the separation process
divides the unit into 4 groups. ............................................................................................................... 58
Figure 34, EoL framework of the redesign B of the IGU. This shape is different compared with the
previous presented frameworks; the starting point is in EoL phase 1 and the separation process
divides the unit into 3 groups. ............................................................................................................... 58
Figure 35, Assessment results in ‘+’ and in ‘‐‘ compared with the current design. .............................. 61
Figure 36, a sketch of the possible application of a new float glass type. On top the standard glass is
positioned and at the bottom recycled glass is in such way placed that field of vision and the
incoming light is not blocked. ................................................................................................................ 64
Figure 37, left, assembly of transparent burglar resistant foil. It can be bought in a regular building
material shop for amateurs (Gamma). On the right a butterfly presenting a possible future
perspective on the IGU. With the transparency and physical properties similar to the butterfly wing a
one material IGU is ideal for recycling. ................................................................................................. 65
Figure 38 technical notes on post and beam façade (Knaack 2008) ..................................................... 75
Figure 39, Unitised comparison with the post&beam system (Knaack 2008) ...................................... 76
Figure 40, trisco temperature flow outcome for current design (left) and the redesign B3.
Temperature flow differences are especially seen in the area of the edge of the IGU. It must be said
that the colors are misleading and focus must be on the starting point of the blue line. .................... 79
69
References:
Artzman, D. (2010).Recycling of Facade System. Unpublished Master thesis, Hochschule
Ostwestfalen‐Lippe, Bielefeld.
Berge, B. (2009). The Ecology of Building Materials ‐ second ed. Oxford: Elsevier Architectural Press.
Boin, U. (2004). Collection of aluminium from building in europe. European Aluminium Association &
University of Technology Delft. http://greenbuilding.world‐
aluminium.org/uploads/media/1256563698Delft_Brochure_and_TU_Delft_Report.pdf
Brand, S. (1994). How buildings learn, what happens after they’re built? New York, Viking Press.
Brockmann, W. (2002). Refinement by joining. In: VDMA (eds). Verband Deutscher Maschinen‐ und
Anlagenbau e.V. Messe Duesseldorf Gmbh, Duesseldorf. pp158‐174
Crowther, P. (2005). Design for Disassembly – Themes and Principles. In RAIA/BDP Environment
Design Guide, August 2005.
Crowther, P. (2001).Developing an inclusive model for design for deconstruction. In CIB TG 39,
destruction meeting, Wellington, New Zealand, 2001.
Ebbert, T. (2010). Refurbishment strategies for technical improvement of office facades. Unpublished
PhD thesis, University of Technology Delft, Delft.
Fletcher, S. L., Popovic, O. & Plank, R. (2000) Designing for Future Reuse and Recycling. Proceeding of
the Deconstruction ‐ Closing the Loop conference, BRE, Watford, UK. 18 May 2000.
Guequierre, N. M. J. and Kristinsson, J. (1999).Product Features that Influence the End of a Building.
In: Lacasse,M. A.,Vanier, D.J. (eds). Proceedings of the 8th Durability of Materials and Components
Conference, May 30‐June 3, 1999. 8dbmc, Vancouver Canada. pp2021‐2032
Guy, B. & Ciarimboli N. (2005). Design for Disassembly in the built environment. Inc. by the Hamer
Center for Community Design, the Pennsylvania State University.
http://www.lifecyclebuilding.org/files/DfDseattle.pdf
Hall, K. (2008). Windows and glazings. In: Hall, K. (eds).The green building bible. Green Building Press,
Llandysul. (4)1. pp217‐220
Hegger, M., Fuchs, M., Stark, T. and Zeumer, M. (2008). Energy Manual. Basel Boston Berlin:
Birkhäuser Verlag AG.
Hendricks, Ch.F. (1999). De bouwcyclus. University of Technology Delft, Delft.
IEBM (2008), Lebensdauer von Bauteilen und Bauteilschichten. IEBM: Institut für Erhaltung und
Modernisierung von Bauwerken e.V. an der TU Berlin, Berlin. 4.2
Kronenburg, R. (2008). Portable architecture. Basel Boston Berlin: Birkhäuser Verlag AG
LCI (2007). What is Lean Construction? Lean Construction Institute, from website
http://leanconstruction.org/ (08‐03‐2011)
70
Lichtenberg, J. (2005). Slimbouwen.Aeneas, Boxtel
Papanek, Victor (1995). The Green Imperative: Natural Design for the Real World, New York, Thames
and Hudson.
SETAC. (1993). Guidelines for Life‐Cycle Assessment: A Code of Practice. Brussels, Belgium.
Thormark 2000, Thormark, C.(2000). Including recycling potential in energy use into the life‐cycle of
buildings, Building Research & Information, (28)3. pp176‐183
United Nations. (1987). Report of the World Commission on Environment and Development. 96th
plenary meeting 11 December: UN.
USGBC (2010). Intro ‐ What LEED Is. U.S. Green Building Council Retrieved, from Website
http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1988 (01‐02‐2011).
Verhoeven, A.C. (1984). Bouwfysica 1. Delft University Press, Delft
Woon/Energie (1991)
Yeang, K. (2008). ECODESIGN, a manual for Ecological Design. Washington, Island Press.
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Appendix A: Crowther ‘s DfD strategy list in detail
This DfD strategy list is created by Crowther (2005): 1. Use recycling and recyclable materials to allow for all levels of the recycling hierarchy, increased use of recycled materials will also encourage industry and government to develop new technologies for recycling, and to create larger support networks and markets for future recycling.
2. Minimise the number of types of materials this will simplify the process of sorting during disassembly, and reduce transport to different recycling locations, and result in greater quantities of each material. 3. Avoid toxic and hazardous material this will reduce the potential for contaminating materials that are being sorted for recycling, and will reduce the potential for health risks that might otherwise discourage disassembly. 4. Avoid composite materials and make inseparable products from the same material In this way large amounts of one material will not be contaminated by a small amount of a foreign material that cannot be easily separated. 5. Avoid secondary finishes to materials such coatings may contaminate the base material and make recycling difficult, where possible use materials that provide their own suitable finish or use mechanically separable finishes (Note: some protective finishes such as galvanising may still on balance be desirable since they extend the service life of the component despite disassembly or recycling problems). 6. Provide standard and permanent identification of material types many materials such as plastics are not easily identifiable and should be provided with a non‐removable and non‐contaminating identification mark to allow for future sorting, such a mark could provide information on material type, place and time or origin, structural capacity, toxic content, etc. 7. Minimise the number of different types of components this will simplify the process of sorting and reduce the number of different disassembly procedures to be undertaken, it will also make component reuse more attractive due to greater numbers of fewer components. 8. Use mechanical rather than chemical connections this will allow the easy separation of components and materials without force, reduce contamination of materials, and reduce damage to components. 9. Use an open building system with interchangeable parts this will allow alterations in the building layout through relocation of component without significant modification. 10. Use modular design and coordination use components and materials that are compatible with other systems both dimensionally and functionally. This type of modular co‐ordination, that today we in some part take for granted, not only has assembly advantages, but clearly also has disassembly advantages, such as standardisation of disassembly procedure and a broader market for reused components. 11. Use assembly technologies compatible with standard, simple, and low‐tech building practice and common tools specialist technologies will make disassembly difficult to perform and a less attractive option, particularly for the user. Specialist technologies, materials, and systems that have limited application today may not be readily available in the future when a building is to be disassembled. 12. Separate the structure from the cladding, internal walls, and services to allow for parallel disassembly such that some parts or systems of the building may be removed without affecting other parts. Most construction methods can be considered as being either a system of load bearing walls, or a system of separate structural frame and in‐fill. The system of separate frame and in‐fill is by far the more compatible of the two with a range of disassembly requirements. 13. Provide access to all parts of the building and to all components ease of access will allow ease of disassembly, allow access for disassembly from within the building if possible. 14. Design components and materials of a size that suits the intended means of handling allow for various handling operations during assembly, disassembly, transport, reprocessing, and re‐assembly. The handling of building materials and components is an important consideration in any building, more so if the building is to be disassembled and components later re‐assembled. 15. Provide for handling the designed system’s components during assembly and disassembly handling may require points of attachment for lifting equipment as well as temporary supporting and locating devices. The provision of a means of handling components is not often considered in building design because the current approach within the building industry is that a component will only be handled once during the initial assembly. 16. Provide realistic tolerances to allow for maneuvering during disassembly the repeated assembly and disassembly process may require greater tolerance than for the manufacture process or for a one‐off assembly process. 17. Minimise number of fasteners and connectors to allow for easy and quick disassembly and so that the disassembly procedure is not complex or difficult to understand. Such a principle will assist in the repair of the component or in the rebuilding of it, though it is not so relevant for the reclaiming (for recycling) of the material, which might be recovered by simply breaking the component. 18. Minimise number of different types of fasteners and connectors to allow for a more standardised process of assembly and disassembly without the need for numerous different tools and operations. 19. Design construction joints and connectors to withstand repeated use to minimise irreparable damage or distortion of components and materials during repeated assembly and disassembly procedures, to allow for the rigors of repeated assembly and disassembly. 20. Allow for parallel disassembly rather than sequential disassembly so that components or materials can be removed without disrupting other components or materials, where this is not possible make the most reusable or ‘valuable’ parts of
72
the building most accessible, to allow for maximum recovery of those components and materials that are most likely to be reused. 21. Provide permanent identification for each component in a co‐ordinated way with material information and total building system information, ideally electronically readable to international standards. 22. Use a standard structural or coordinated component grid the grid dimension and orientation should be related to the materials used such that structural spans are designed to make the most efficient use of material type and allow coordinated relocating of components such as cladding. This will also result in more components of same/standard size, and the grid responds to issues of material efficiency. 23. Use prefabricated subassemblies and a system of mass production to reduce site work and allow greater control over component quality and conformity. The prefabrication of these components reduces the amount of on‐site work required and thereby eases the process of assembly, and later disassembly, of the building. 24. Use light weight materials and components this will make handling easier and quicker, making disassembly and reuse a more attractive option. This will also allow disassembly for regular maintenance and replacement of parts. 25. Identify point of disassembly permanently so as not to be confused with other design features and to sustain knowledge on the component systems of the building. As well as indicating points of disassembly, it may be necessary to indicate disassembly procedures as instructions. 26. Provide spare parts and allow for their storage particularly for custom designed parts, both to replace broken or damaged components and when required for minor alterations to the building design. Storage for spare components is an integral part of the building design. 27. Retain all information on the building construction systems and assembly and disassembly procedures efforts should be made to retain and update information such as ‘as built’ drawings including all reuse and recycling potentials as an assets register. The retention of such complete information about the whole building enhances its potential value for relocation, reuse, or recycling.
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Appendix B: Galeria Kaufhof sections (1:10)
74
75
Appendix C: On & Offsite built facades
Current facades are mainly designed with the objective to perform and to allow easy assembly.
Important with regard to DfD is whether a façade is assembled on‐site or off‐site (in a factory). Both
facades have a certain assembly procedure on‐site, but the on‐site assembly façade requires
significantly more work on site.
In the commercial facade the materials used are in general the same: aluminium, glass and/or
different cladding materials, insulation and connectors.
On‐site built facades
There are three types of on‐site built facades. A distinction is made between assembling a sealed
construction (post&beam and breastwork facades) or a screen protecting the building against the
rain (cladding).
Impermeable facades are sealed and only permit the passage of water at joints. This is created by
sealing joints with gaskets and finishing them by a strip. This seal is frequently built on buildings with
a relatively small outer surface because of the amount of manpower needed.
The cladding (rainscreen) shields the wall from rain. The joints between the panels may allow some
water to penetrate but an air gap and airtight backing wall behind the panels limit this.
Off‐site built facades
The unitised system is the only system that has a main focus on the off‐site phase of the assembly
process. It is pre‐assembled under controlled factory conditions and has a minimum floor span
height. It can also easily be mounted on‐site. The reduced number of on‐site prepared joints
compared with on‐site built systems, generally leads to a reduction in air and water leakage resulting
from poor installation. This system is increasing its share on the facade market with a more complex
framing compared with the on‐site built system. As capital expenditures are high, this system is often
only profitable on large outer surfaces, with repetition causing the costs to drop.
On‐site built systems, technical notes:
‐ Insufficient space is allowed for expansion and movement, caused by thermal change, deflection of slabs and building settlement
‐ No quality check, mistakes can easily be made due to a lot of on‐site assembly
‐ Measurement mistakes in other building elements can be solved relatively easily
Figure 38 technical notes on post and beam façade (Knaack 2008)
Unitised system comparison with post&beam system:
‐ Better quality can be assured, the products are tested. (reduction in air and water leakage)
‐ Thicker facade elements ‐ Less tolerant for measurement mistakes in
other building elements ‐ Less dependent on the weather conditions
when assembled
A short study on the ratio of on‐ versus off‐site built commercial facades resulted in concluding that
it’s hard to estimate the current situation7. Extended research is needed to find the difference in
facade surfaces. Though future estimations can be made based on costs and quality:
‐ The on‐site built facade will always be too expensive for ‘big’ buildings and the off‐site built
facade will have to cope with a lot of technical difficulties before being cost effective for
‘small’ buildings.
The quality level of the off‐site system is higher, because of the control in the factory. This
enlarges the chance of the facade to last at least 20 years and technical advancements can
be introduced easier.
7 Director of the Dutch knowledge centre on facades in email contact mentioned the following, Panhuijs: ’the unitised facade system is increasing in tghe amount of production in the Netherlands’. Two interviews within Arup Berlin: 50% – 50%, a rough estimation within the Arup’s projects.
Figure 39, Unitised comparison with the post&beam system (Knaack
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Appendix D: Drawings of all designs (2:1)
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Appendix E: Calculation outcome on different cavity contents Two calculations are made with the programme Windows 5 to see the performance difference between the cavity content of a 90% and 75% filled with Argon gas. Take into account that due to the complex calculation of the IGU manufacturer a difference is created between the in this thesis used simplified calculation programme. A 1.7 W/m2K higher than the 1.2 W/m2K mentioned in the report. Calculation with 90% argon gas in between the glass panes: 1.37 W/m2K
Calculation with 75% argon gas in between the glass panes: 1.42 W/m2K
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Appendix F: Assessment with Trisco outcome
The calculation of the u‐value of the IGU is a complicated process, IGU manufactures have applied
multiple calculations to come to the current values. In this appendix it is shown that without a full
calculation a decision can be made for the assessment; the comparison between the current design
and redesign B3.
When calculating the thermal performance of the IGU the conductivity of every integrated material is
needed with its dimensions. The ‘u‐value’ mentioned in the assessment is showing the heat loss for
every square meter, the u‐value’ of the following materials are presented:
Glass: 5.7 W/m2K
Aluminium: 200 W/m2K
Thermal plastics: 0.2 W/m2K
EPDM: 0.2 W/m2K
Argon gas: 0.017 W/m2K
Poly butyl sealing: 0.25 W/m2K
Air: 0.05 W/m2K
Figure 40, trisco temperature flow outcome for current design (left) and the redesign B3. Temperature flow differences are especially seen in the area of the edge of the IGU. It must be said that the colors are misleading and focus must be on the starting point of the blue line.
80
The additional EPDM material around the IGU causes the thermal value to drop. The material EPDM
has a higher conduction compared with the conductivity of air. This is also seen in the figure 40
where it is clear that, redesign B3, the blue area starts more to the inner side of the section. With a λ
of 0.2 on a surface of 0.032 square meters the EPDM causes a heat loss between 0.1 and 0.3 W/m2K.
Estimation of the u‐value is between the 1.3‐1.5 W/m2K
