Developing Strategic Framework for Adaptive Building Envelopes

Developing A Strategic Framework For The Design Of
Adaptive Building Envelopes
Ramy Mosa
H00142673
A dissertation submitted in partial fulfillment of the requirements for the degree
of
Master of Science in Architectural Engineering
D11ZZ: 2017-2018
Dissertation supervisor
Dr. Alex Maclaren
Heriot-Watt University
School of the Built Environment
July 13, 2018

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Declaration
I the undersigned, Ramy Mosa, confirm that this work submitted for assessment is my own and is
expressed in my own words. Any uses made within it of the works of other authors in any form (e.g.
ideas, equations, figures, text, tables, programs) are properly acknowledged at the point of their use.
A full list of the references employed has been included.
Signed: ……………………………. Date: Friday, July 13, 2018

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Abstract
Adaptive Building Envelopes
The potentials and challenges facing developing adaptive envelopes
Every year, millions of buildings are constructed worldwide to provide protection and required comfort
for occupants to live and practice their activities. The building shells are critical elements that have
direct and indirect impacts on occupants, building performance and the whole built-environment.
While the context of any built-case is a mix of various altered attributes; buildings and most of their
components (except the electromechanical artificial systems) are designed based on “static state
concept” which have initially defined design criteria to perform regardless the contextual attributes
status. A corollary of that we have a static performance (building components and systems) to act
against dynamic contextual attributes. Therefore, designing a dynamic building shell becomes a
potential approach for the sustainable buildings construction industry. Even though, there is a tiny
amount of buildings around the world that have been designed based on that approach and have been
constructed.
The main aim of this thesis is to provide insight into the design of the adaptive envelopes, to explore
the concept’s aspects, strategies and what are both, potentials and benefits that can be gained and, on
the other side, risks and challenges that may be faced throughout the envelope life journey (from
planning and design up to post-operate). Research mission is to develop a strategic framework for the
design of the adaptive building envelopes to aid and support the built-environment community to
employ this concept more in the future.
The research starts with a literature review to define the adaptive envelope concept, terms and trends.
followed by an exploration of the values of the concept through an analytical comparison between
different case studies. The case study approach allows in-depth, multifaceted explorations of complex
issues in their real-life settings. Then findings have been formed, basically, an adaptive design
strategies taxonomy which is conceived as a critical part of the frame-of-work that has been, mainly
initiated for further development in the future.
Keywords
Dynamic Facades, Adaptive Envelopes, Kinetic Architecture, Intelligent Skins.

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Table of Contents
Declaration.......................................................................................................................................... 3
Abstract............................................................................................................................................... 4
Table of Contents ............................................................................................................................... 5
1. Introduction.................................................................................................................................. 8
Background .......................................................................................................................... 8
Future challenge................................................................................................................... 9
Aim ....................................................................................................................................... 9
Objectives............................................................................................................................. 9
Research methodology....................................................................................................... 10
2. The Adaptive Envelopes............................................................................................................ 12
Historical review of “The development of the dynamic envelope notion” ........................... 12
Concept definition............................................................................................................... 18
2.2.1 The associated terms.................................................................................................. 21
2.2.2 Proposed definition...................................................................................................... 21
Factors influencing and benefits of adaptive envelopes..................................................... 22
2.3.1 The contextual attributes............................................................................................. 22
2.3.2 Envelope performance model ..................................................................................... 24
Developing an adaptive envelop ........................................................................................ 25
Attempts for classification................................................................................................... 27
Proposed taxonomy of adaptive design strategies............................................................. 29
Section Summary ............................................................................................................... 30
3. Case Studies ............................................................................................................................. 31
The practice of the adaptive envelope design around the world ........................................ 31
Cases examination method................................................................................................ 32
Case Study – 1, Bosco Verticale, Milan ............................................................................. 34
3.3.1 Case overview............................................................................................................. 34
3.3.2 Context and design attributes...................................................................................... 34
3.3.3 The adaption technique............................................................................................... 35
3.3.4 Design methods and tools........................................................................................... 38
3.3.5 Findings....................................................................................................................... 39
Case Study – 2, HygroSkin - Meteorosensitive Pavilion .................................................... 41
3.4.1 Case overview............................................................................................................. 41
3.4.3 The Adaptation technique ........................................................................................... 41

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3.4.5 Findings....................................................................................................................... 44
Case Study – 3, Manitoba Hydro Place.............................................................................. 45
3.5.1 Case overview............................................................................................................. 45
3.5.3 The Adaptation techniques.......................................................................................... 46
3.5.5 Findings....................................................................................................................... 52
Case Study – 4, Mega-Faces............................................................................................. 53
3.6.1 Case overview............................................................................................................. 53
3.6.3 The Adaptation technique ........................................................................................... 54
3.6.5 Findings....................................................................................................................... 56
Case Study – 5, Sharifi’Ha House...................................................................................... 57
3.7.1 Case basic information................................................................................................ 57
3.7.3 The adaptation technique............................................................................................ 57
3.7.5 Findings....................................................................................................................... 61
Section Summary ............................................................................................................... 62
4. Findings and Recommendations ............................................................................................... 63
The adaptation process...................................................................................................... 63
Bases of proposed taxonomy............................................................................................. 65
4.2.1 Objective and functionality: ......................................................................................... 65
4.2.2 Relevant physical nature of the adaptive feature ........................................................ 65
4.2.3 The adaptation technology and control method .......................................................... 65
4.2.4 Scale of adaptation...................................................................................................... 66
4.2.5 Time scale................................................................................................................... 66
Adaptive envelopes design strategies taxonomy ............................................................... 66
4.3.1 Living envelopes:......................................................................................................... 67
4.3.2 Intelligent skins:........................................................................................................... 68
4.3.3 Kinetic envelopes: ....................................................................................................... 69
4.3.4 Media façade:.............................................................................................................. 70
4.3.5 Transformable architecture: ........................................................................................ 71
Comparative analysis of the adaptive strategies................................................................ 72
4.4.1 Analyzing the strategies based on the typology criteria .............................................. 72

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4.4.2 SWOT analysis between the adaptive strategies........................................................ 72
The hybrid adaptive design ................................................................................................ 75
Section summary................................................................................................................ 76
5. Observations on the design process and the adaptive envelopes execution ............................ 77
The practice observation .................................................................................................... 77
Suggested roadmap for the design and execution............................................................. 77
5.2.1 Comments on the flowchart......................................................................................... 81
Challenges in success........................................................................................................ 82
5.3.1 The success keys........................................................................................................ 82
5.3.2 The challenges............................................................................................................ 82
6. Conclusion................................................................................................................................. 84
Limitations of the study....................................................................................................... 84
Revisit the research questions ........................................................................................... 85
Suggestions for future research work................................................................................. 85
7. Acknowledgement ..................................................................................................................... 87
8. Imagery credits .......................................................................................................................... 88
9. List of Figures ............................................................................................................................ 90
10. References............................................................................................................................. 93

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1. Introduction
This section describes and outlines the scope of this thesis, the motivational background, defining the
aim and the objectives of this work and finally, the methodology of conducting the research studies.
The field of “Buildings Envelope”, the core of the study, is a point of contact between different
interests in construction industry. Due to its importance, the research questioned one of the trends that
has a potential for future development which so-called adaptive, responsive dynamic or kinetic façade.
These questions are positioned within this section as well.
Background
On April 3, 1973, Martin Cooper, a Motorola researcher and executive, made the first mobile
telephone call from a handheld subscriber equipment (Shiels, 2003). At that time, no one imagined
that within less than 50 years after this step, the majority of humans will rely on smart phones to
manage their daily life. The concept took 50 years of research and experiments after Martin handheld
phone of 1.2 kilograms. The significant functional improvement and effectiveness in people’s life are
a result of technology development by creative and ambitious minds. Obviously, building’s envelopes,
facing the same challenge to evolve on a way to become more functional, economical and intelligent
while respecting the modern needs and responding to the global concerns.
The motivation of “modern buildings envelope” is founded in the tension field of three main
magnitudes. The first one renowned as “the global energy concern”. Buildings as a main consumer of
energy and planet resources are subject for sustainability concern. Which push the industry to introduce
more sustainable solutions for each aspect of buildings’ components. The second magnitude is the
spread of modern building sciences. The growing knowledge about building systems, material
properties, and occupant comfort and behaviors are supporting more efficient solutions which help to
improve the building’s performance and can serve the first magnitude as well. Additionally, the smart
or the intelligence trend. Which force a combination of both magnitudes to result more innovative and
futuristic ideas for buildings’ components, systems and materials.
In fact, adaptive envelopes concept, which is a theme of modern building envelope, is not a new
speculated trend during the recent decades as it may appear. The notion of interacting and adapting
building shells has been introduced since hundreds of years ago. The operable windows and traditional
curtains have been used along the building history as a simple interaction between the envelope and
external environment controlled manually by occupants. The key principle of this straightforward
solution is to provide the desired day lighting, maintain privacy and security without hiding the
external views. Solutions were tailored around the world according to each country’s local cultural
considerations.
While the early days of the adaptive concept were driven by simple cultural needs, basically the
privacy, daylighting, protection from outdoor climate conditions, and security controlled the design
criteria, the 21st
Century concerns are totally different. Since 1970s, energy was considered as the chief
driver for most of architectural practices (Russel Fortmeyer and Charles D. Linn, 2014). Sustainable
design became a major trend forced by either construction codes, regulatory standards, client’s
requirement or even designer interest. Another concern is the social interaction between buildings and
community. Building’s exterior character is not anymore a static image. They have a prime role in
cities interaction with societies. Building facades became a media platform to transfer messages to
people. This approach is considered as an echo of social media era.

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Figure 1-1, Adaptive strategies of ancient buildings. Window shutters, screens and curtains were used to provide interaction between
external, internal conditions and occupant requirement. (From left);1. photo of shutters from Thomas Jefferson’s Monticello, USA
(1772). Stiles and rails (the edges) on early louvered shutters were quite narrow. 2. Islamic Mashrabia a traditional solution to
provide daylighting while maintaining desired privacy. 3. Chinese Malay Colonial architecture, Penang Old town. Wooden shutters
allow securing windows by complete closing.
Future challenge
The challenge of how building envelopes will respond to human needs and the built-environment
concerns in the future become a fertile area for developing the industry. Escalated expectations from
buildings raising for protecting shells to zero-energy buildings then finally to be energy producers,
these expectations promote developing more effective building solutions, which are able to standout
to face this challenge. Adaptive envelopes respond in real-time basis to the modern needs could be one
of the potential answers to this challenge. This is why the research explores this area of the modern
building envelopes. The concept is an effecitve approach to deal with the 21st
centruy concerns.
Predicting the future, it might be a common practice within few years
Regardless a few built-cases around the world, the concept of adaptive enevelop is almost, in a
qantitive comparision with conventional static façades, is considered as a limited practice. Therefore,
most of these built-cases are considered as counted landmarks. Examining the benefits, opportunities,
challenges and risks facing this concept will support the process of prducing effective adaptive designs.
Aim
The thesis intrinsic is to respond to the hypothetical questions about “the future of façade design” and
to explore “the concept of dynamic envelops”. Believing in the potential of adaptive and responsive
building design, the research attempts to discuss (in-depth) the concept definition and strategies,
challenges, risks, benefits and potentials of the adaptive building envelopes.
Aiming to motivate architects to consider this concept more in their practice by answering the critical
questions; why the concept should be considered, how it could be designed to maximize the benefits
and what are the critical issues that should be conceived before, during the design process and even
post-operation. Consolidating this knowledge by developing a frame of work to support future designs
and open the door for more in-depth studies, researches and experiments.
Objectives
The research attempts to develop a holistic approach to analyze, define the concept, and classify the
adaptive strategies, while paying attention to other aspects of the concept like; factors inspiring and
influencing the adaptive design “attributes”, metrics to measure the achievements “performance
model” and process of developing the adaptive design.
The core objective is to obtain knowledge of the adaptive envelopes design aspects to the architecture
community and building industry which can assist in future design practice. To achieve this goal, the
research links the theoretical studies to the industry practice by reviewing the concept state-of-the-art

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and conducting a descriptive analysis of built cases which, both, are giving comprehensive feedbacks
on the notion aspects and field practice.
These objectives will be gained through the results of this work which are outlined into either findings,
recommendations or suggestions shown as follows:
› Define a taxonomy for classifying adaptive envelope design strategies
› Observation in the practice to define measurements of success based on the triple bottom lines:
environmental, economic and social in addition to the challenges facing the concept.
› Suggest a methodology of execution that can be considered as a base for future envelope design
processes.
Research methodology
The execution methodology of this research is based on exploring the adaptive envelopes from two
directions; one is theoretical while the other is practical. Which ensure the comprehensive
understanding of the concept aspects and consolidate the base to develop the research outcomes.
The first direction is a literature review of concept history of development, definition, limitations and
typology of adaptation strategies. This discussion leads to a proposed definition of the concept and the
process, outline the factors influencing or impacting the process and developed taxonomy of adaptation
design strategies. The second direction is the examination of real-built case studies which is
investigating how the concept deployed on buildings industry. Accordingly, these findings, from both
directions, are used to formulate and develop a strategic framework of the adaptive building envelopes.
The findings are summarized at the end of each section while they are discussed in details at the last
two sections. In general, the research methodology phases are described as follows:
 Initiation:
Consolidate the background, aim and objectives of the work. Developing the methodology of
executing the research.
 Phase 1 - Definition Phase:
During this phase the adaptive envelope concept aspects is discussed literately. Aspects like
definitions, terminologies, factors and attributes, trends and types are explored to define the
concept limitations.
 Phase 2 - Examination of concept practising by analyzing case studies:
Real-built and operated case studies are selected to be analyzed and critically compared
against the definition, design trends, strategies and methods of design. Comparison criteria is
organized in such a way that the concept has been literately reviewed to consolidate the
feedback of both research phases into the next phase.
Phase 3 - Concluding the findings to shape the outputs:
The findings of phase 1 and 2 are consolidated to develop the framework of the adaptive
envelope design. Findings of the research are classified into two sections due to the
development level; process definition and strategies taxonomy (the main) and suggested
methodology of execution and measurements of success (supportive)
 Closing:
Discusses the research question and potential areas for future research.

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Figure 1-2, The schematic of the dissertation

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2. The Adaptive Envelopes
This part of the thesis discusses the adaptive envelopes’ concepts and typologies through a literature
review. Beginning with an exploration of the notion history and how it has been evolved, followed by
a crucial discussion in the concept definition and terminology. The concept and terms should be
clarified and a border between various aspects should be drawn. This helps to comprehend the
objectives, benefits and techniques used by each approach of adaption concepts. Then further
discussions on the adaptation typologies and how are they influenced by the contextual attributes. In
addition to a briefed discussion on the design and execution processes of the adaptive envelopes. The
literature background provides the required knowledge to review and evaluate the examined case
studies at the following section.
Historical review of “The development of the dynamic envelope notion”
Since the existence of the human culture-both ancient and modern-, the ultimate goal of the building
industry was to shelter people and their activities from the undesired outdoor environmental conditions
and to ensure the comfort level provision “for most of the users” that supports human activities and
building functions. To achieve this goal, there are assorted variations in building’s components
performance, in particular, the envelope or the shell, will be needed due to the changes of both external
and internal conditions. Throughout the buildings history, these performance variations were achieved
physically by two main approaches. The first one is the adaptation of building components, for instance
operable windows, indoor curtains or operating a fireplace. The second approach is the responsive
behaviors and activities of the occupants themselves; for instance, wearing heavier clothes during
winter or switching on and off the artificial lights. Both approaches are essentially controlled by
occupant interests.
Ancient buildings
The approach that deals with contextual conditions is basically linked to buildings’ components and
construction types. While the caveman was not able to enhance the indoor environment through
adaptation of building components due to the shell he used. Later on, the ancient buildings with doors
and operable windows assisted the adaptation needed. Introducing the technique of providing a tiny
opening in the building shell was a result of using the load-bearing construction methods instead of
natural caves. This construction principle gave the builders the opportunity to consider lighter
materials, mainly wood, with flexible hinging joints to provide operable openings on the building walls
(Yu, 2014). This technique is controlled by occupants to secure their territories and adapt the
exchanges with the outdoor environment conditions.
The load-bearing principle has been widely used worldwide with different materials and methods of
construction. The concept has been developed with different shapes from simple stone or bricks of
clay walls into brick blocks strengthened by wood or steel frames then evolved by the concept of light
frame structures. (Yu, 2014). Therefore, the size of the openings, materials and the connections
methods may vary according to the cultural conditions and available resources. But there was only one
way to control the operation, which was the occupant. And the condition of operation is his activity
requirement, feelings or needs.
Building facades significantly evolved once glass has been introduced in buildings construction as a
prime filling material for walls or windows or as a second layer for openings “simple shape of a double
skin façade”. The transparency and the visual connection with the outdoor views became the client’s
ambitious requirements and expectations as a design driven force. Hardwick Hall - 1597 could be considered

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as the all-glass load bearing buildings start taking-off. The wall was designed with large openings to
respond to this new requirement (Fortmeyer and Linn, 2014). Hardwick’s wall was designed with wide
and tall windows, which are able to be controlled by indoor curtains which provide both visual
connectivity with the outdoor garden and meanwhile the privacy needed for building habitats.
Windows size are tailored based on the social level of occupants in each level. While wide the windows
were provided to elite people occupying the higher levels while smaller windows to humble people
occupying lower levels “servants and security”.
Figure 2-1, Hardwick
Hall, Derbyshire,
England. By Architect
Robert Smythson - 1597
(From left) 1. An exterior
image shows the wide
tall windows that allow
the connectivity between
indoor and outdoor
spaces, 2. Interior image
shows the use of curtains
to provide privacy.
Non-load-bearing construction
During the 18th
and 19th
centuries, the greenhouses, horticulture buildings were established due to the
need for wide span spaces and controlled indoor-environment which influenced the glass architecture.
Architects like Joseph Paxton adapted further the use of glass as a filling material to replace inter
volumes of walls. From dynamic façades historical view, this point is a milestone. Glass as a light
material has influenced the concept of adaptive building envelopes. It provides both desired functions;
protection from external environment conditions “for certain limit” and, meanwhile, allows the
transition of the natural day-lighting to the indoor spaces in addition to the visual interaction between
indoor and outdoor.
The concept of passive design has witnessed a
scientific breakthrough as well. Architects and
builders developed the design strategies that
reinforced the use of energy. The construction of
Hothouses employed strategies which bring
cooled and fresh air that depend on passive
ventilation, operable sashes and louvers at the
bottom, and ridge vents at the top (Fortmeyer and
Linn, 2014).
Both design strategies; glass architecture and
passive design, are conceived as key influencers
for the dynamic façade concept. The operable
windows, shutter curtains and louvers became
prevalent at that time. These building components and their associated systems were controlled by
either the occupants themselves or the building management staff. Throughout this period, there wasn’t
much concern about energy nor the scarcity of resources. The objectives of employing this level of
envelope adaptation were essentially driven by occupant’s comfort and functional requirements.
Figure 2-2, Chatsworth Conservatory and Lily House,
Edensor, Derbyshire, UK. By Sir Joseph Paxton, date (1836 –
1840), and (1849 – 1850)

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The modern style, 20th
century.
Most of researchers are dating the history of dynamic facades concept to the first five years of the 20th
century due to two significant inventions. On one hand the air-conditioning systems and the success
of employing it in buildings industry by Willis Carrier 1902. Air-conditioning system has transferred
the indoor comfort notion into new levels. While previously, building envelopes were mainly
responsible for protecting indoor spaces from undesired out-door conditions, now, it has to modulate
the transfer of energy between indoor and outdoor beside its other known roles.
on the other hand, the curtain wall concept. While, the dating of curtain wall is a debatable topic
between researchers. (Fortmeyer and Linn, 2014). Some demonstrate that the curtain walls have been
introduced for the first time in Chicago considering the Reliance Building by Burnham and Root,1895
as a key start (Klein, 2013). While Steiff Toy Factory in Germany, 1903 - 1908 considered by others
as the first key built case that employed a full curtain wall concept in wide range (Fortmeyer and Linn,
2014). Despite the strong evidence of the first one, the fact is, the curtain walls have influenced the
building façade in a high level. Curtain walls were employed in parallel to the non-bearing loads
structure to benefit the façade design. These two building systems in addition to the increasing use of
non-load bearing constructions have evolved building façade industry to initiate the International
Modern Style.
These new technologies have been used by several architects to develop active facades. Jean Prouvé
(1901-1984) works could be considered as the apotheosis of the kinetic façade concept (Fortmeyer and
Linn, 2014). Projects like Maison du Peuple, Clichy, France (1935-1939) and Maison Tropicale, West
Africa (1949-1952); he employed concept of the performative role of façade to control the indoor
environment was demonstrated by featuring manually controlled metal shutters, a solar chimney and
overall lightweight metal structure (Suárez Fernández-Coronado, Inés & González Bravo, Raúl, 2010).
The result was a low consumption of energy in use and manufacturing. Other architects fostered the
new style beginnings by their wider and large scale practices; Le Corbusier (1887-1965) and Mies Van
Der Rohe (1886-1969), have proposed a double skin facades with passive design strategies. Some of
these trials employed dynamic features to manipulate the contextual changes. Their practice was
implemented in different climates around the world but no much satisfactory on results “few cases
were significantly successful while most of them have failed”.
Figure 2-3, Maison du Peuple, Clichy, France (1935-1939) by Jean Prouv'e. Double skin facade to control the indoor environment
Figure 2-4, Maison Tropicale, West Africa (1949-1952) by Jean Prouve. An adaptive double skin façade with mechanical louvers

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In 1967, another significant attempt by Buckminster Fuller’s who designed a facade for the United
States pavilion in Montreal Expo. With its climatic responsive concept, the pavilion featured a
geodesic dome which was made of a transparent cladding of acrylic panels, with interior canvas
sunshades controlled by a computer program that would adjust their position relative to the movement
of the sun.
Figure 2-5, Buckminster Fuller Proposal for UN Pavilion - Montreal Expo 1967. from left to right:1. image shows the exterior design
of the dome, 2. image show the interior closed sun shade, 3. images show the installation of the automted sun shade
Despite architect’s practices to examine the concept, the modern style facades, in its principle, consists
of structural skeleton filled either by a transparent or opaque material or mix of both based on various
design philosophies. This vision has been developed by several architects and researchers around the
world to generate the modern building façade. In general, the modern style facade is designed based
on two similar modals. The regular “static” one, which is more popular, lower cost and perform in an
acceptable level for several building typologies. And on the other hand, the advance façade model,
which employed advanced techniques to perform better even if it may influence the cost aspects
significantly.
This modern façade approach or in particular, the dynamic façade concept, has been influenced by two
main factors, crisis one and potential one. The first one is the energy crisis in 1970s which resulted
“The energy as a chief od façade design” and the second one is the potential of building science that
allows architects to understand more about heat, air flows, energy consumed and demanded and the
human comfort. (Fortmeyer and Linn, 2014). Both factors result a more global awareness on building
envelope performance importance and how it can either influence or impact the built-environment.
This awareness leaded to more interest in the advance façade model which employs technology in
different techniques to serve building sustainable performance aspects.
A walk through the last three decades
This period of the adaptive envelopes history was considerably rich in the design practice. However,
there are few cases that should be outlined here to benefit the research scope. This “few” could be
grouped into two groups, group “A” and group “B” to simplify the historical review of the concept
development.
Group “A” has two built cases, both were built in the early 1980s which means they were almost the
eldest modern cases. With about 40 years of operation, they passed through the mostly common
building lifecycle and different indicators are on record. Therefore, a comprehensive assessment can
be conducted to learn more about the adaptive envelope aspects. The two cases designed on bases of
the notion of “Building façade should responses to contextual attributes changes in most sufficient
mechanism”. Both cases will be discussed further in several places in this research.

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The first case is Occidental Chemical Building, New York designed in the late 1970 by Cannon Design
and completed in 1980. The design employed several façade passive design strategies that were relying
on mechanical motorized variable louvers to provide the adequate occupant comfort while maintaining
the energy consumption to the lowest possible point at that time. The design deserved several national
and international awards due to its high performance design that operated perfectly for years. However,
the building has passed through difficult times due to assigning different functions than the original
design intents and maintenance challenges. The result was a building that considered “by public
society” as an abandoned feature within an attractive landscape which requires a demolishing action
from government.
Figure 2-6, Occidental Chemical Building, New York 1976-1980 by Cannon Design. From left to right: 1. exterior image show the
boxy design of the building (all facades are treated in same way. 2. Image shows the cavity between the double skins. 3. Architectural
illustrates the air-flow at the external zone of the building and how it operates in summer and winter timings
In 1982, Jean Nouvel's designed the second case; The Arab Institute in Paris, finished in 1987. This
particular building considered as a masterpiece case and a historical landmark in the field of dynamic
façade design. As it usually been called “the first attempt to develop kinetic façade design” (Radwan,
2016), here for the first time, was a building façade that inspired from the “Mashrabiya” the traditional
Islamic architectural feature, with capacity of 240 photo-sensitive metal apertures to control the solar
gain through opening-and-closing automated operation. This masterpiece is still in operation and
attracting architects from all around the world to visit and enjoy this architectural landmark.
Figure 2-7, Jean Nouvel design of the dynamic screen at the Arab Institute in Paris (1982-1987). The facade which is inspired from
The Islamic Marhrabiya has photo-sensitive apertures o control the natural lighting flow through the screen to the interior spaces
After Nouvel’s masterpiece several attempts were developed between 1980s and late 1990s by what
so-called high-tech architects generally represented by Foster, Rogers, Piano, and others. These
attempts are basically focusing on how envelopes can regulate the solar gain, daylighting and featuring
natural ventilations concepts. In general, the dynamic systems used were automated louvers as shading
devices, wall cavities, solar panels, mechanical and operable windows to allow for natural air flow.
The design key driver was, as mentioned earlier “energy as a chief of design”.

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Group “B” has more built cases with more advance techniques, three cases all are built in 1997. These
cases are Commerzbank Tower, Frankfurt, Germany designed by Foster. The design provides Every
office is daylit and has openable windows, allowing the occupants to control their own environment.
The second one is RWE AG headquarter building, Essen, Germany by Ingenhoven Architects featured
a double skin ecological façade. Both towers (first and second cases) are fighting for the title of “the
first ecological tower in Europe”. And the third is Helicon House Building (EC2 project), London, by
Sheppard Robson the UK's first net zero-carbon mixed-use project. These cases have transformed the
kinetic façade concept into new levels due to projects scale, the scale of adaptation, methods of control
and the achieved results from energy performance perspective.
Figure 2-8, The 1997 key
three cases of adaptive
envelope designs, from
left to right:
1.Commerzbank Tower by
Norman Foster
2. RWE AG headquarter
by Ingenhoven Architects
3. Helicon House
Building or EC2 Project
by Sheppard Robson.
“Climate-based and social interactive” Two new approaches for façade design
Since the beginning of the 21st
century, the communications and technological revolution has
influenced the concept much more through technologies like LED lights, mote, microscopic sensors
and highly efficient actuators. These sort of components opened the door to develop higher complex
façade systems which have different interests. These systems are able to respond to wider range of
contextual attributes based on sophisticated analysis to define more accurate set-points.
Due to the climate change phenomena in addition to the two mentioned factors that influenced the
modern façade design, a higher advance level of façade is generated “The Climate-based Design
Approach for Facades” (Aksamija, 2013). During this era (2000 - today), also, there are two factors
paved the way to this design approach for facades to spread out and widely be considered. The major
one is the limitation of energy sources that pushing the industry to be a wise customer. However,
sometimes the shortage of utility grids could push architects to chase utilities potential savings through
high-performance design strategies or find a way to generate energy from domestic sources “renewable
energy”. On other hand, the evolution of building science which has various aspects. Firstly, the
understanding of energy, heat, air and moister flows through building components, and materials and
related phenomena. Secondly, building design tools to simulate and calculate data that allow architects
and specialists to evaluate systems performance. These two aspects are supported by the industry
booming in technology. The new materials and fabrication techniques that allow sophisticated
geometries and designs to be executed and constructed.
Another new design principle that enriched the adaptive envelope design, this is the “social oriented
design” that generates buildings able to speak, feel and interact with users. The concept employs
intelligent systems and media technologies which tend to interact with building occupants and the
community within the urban context. Features like LED lights, screens, media and even parametric

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texture with shape deformation are used to create a new language between buildings envelope and
communities.
Concept definition
Throughout the literature of the adaptive buildings envelope concept, it has been found that there are
several attempts to define the concept and its limitations by researchers. The different concept aspects
turn the definition into a challenging path. Untill now, there is no a well-defined boarder for concept
aspects because of the limitation of each study (Gosztonyi, 2015). This area is fertile for further
development in future researches. Defining the concept allows designers and developer to know its
limitation, associated scientific concepts and how it could be developed further in future. Furthermore,
it has been found that most of researches are focusing into the climatic-based adaptive façade which
give a potential for more defined boarders for the concept, while considering other concept aspects out
of scope. These drawbacks a limited concept definition attempts focusing on some aspects (even
though these aspects are the most crucial) while ignoring others.
Examining the concept definition by Loonen (who has significant number of researches on the topic),
he was clear that he limited the definition to the so-called CABS (Climate Adaptive Building Shells)
while he considered a number of building shell technologies that do qualify as e.g., active, advanced
or interactive fall outside the scope of his work (R.C.G.M. Loonen, M. Trčka, D. Cóstola, J.L.M.
Hensen, 2013). From his perspective, these façades do introduce dynamic aspects to the building, but
do not have the means to effectively influence perceived indoor climate (which is the definition
boarder). So that, his CABS definition states: “A climate adaptive building shell has the ability to
repeatedly and reversibly change some of its functions, features or behavior over time in response to
changing performance requirements and variable boundary conditions, and does this with the aim of
improving overall building performance”. The definition covers various used terms like: active,
advanced, dynamic, intelligent, interactive, kinetic, responsive, smart, and switchable.
Chloë Marysse has a significant attempt, she examined the term “adaptive” and compared the
definition and terms used by other researches to come up with a comprehensive literature review. Her
final definition states: “An adaptive façade has the ability to adapt, in real time, some of its functions,
features and behavior in response to changing environmental conditions, performance requirements,
occupants’ wishes or other boundary conditions (e.g. space efficiency). The adaption has the purpose
to obtain improved overall building performance related to primary energy use (heating, cooling,
ventilation and lighting) while maintaining or enhancing the comfort and increasing the flexibility
during the life phase of the building” (Marysse, 2016). From her point, the climatic and indoor
environmental quality are dominating the direction of the concept. Time is more concerned here than
Loonen definition. The statement of “real time” strengths the importance of the time scale of the
adaptation concept. Both definitions agreed on the term “boundary” for contextual and environmental
conditions which relates to natural and manmade with less attention to humanity aspects (occupant
behavior and social requirements). Marysse gave a special attention to the structural definitions to
differentiate between concepts like adaptable, transformable, and deployable.
Some other attempts went step back to understand the definition approach. Susanne Gosztonyi
supported the idea that the definition is more linked to the used strategy (Gosztonyi, 2015). Reviewing
her approach, it was found that, while most of researches are exploring the notions behind the
systematic approach of the dynamic facades e.g. (Marta Barozzi, Julian Lienhard, Alessandra Zanelli
and Carol Monticell, 2016), there are some concepts are associated to the materialization of the system
(material and/or mechanical system). Some researchers have emphasized these concepts. For instance,

19
Attia stated: “Adaptive facades are multi-parameter high performance envelopes that, opposite to fixed
facades, react mechanically or chemically to external climate dynamically to meet internal loads and
occupant needs” (Shady Attia, Fabio Favoino, Roel Loonen, Aleksandar Petrovski, Aurora Monge-
Barrio, 2015). By analyzing this definition, the term “chemical’ is linked to the material aspects. Also,
it has more appreciation towards occupant needs (which is not necessary based on climatic concerns).
Addition to the term “adaptation”, Marta has introduced the definition by differentiating between the
terms of the building system; shell, skin and envelope.
Analyzing the used concept aspects, it has been found that there are a wide range of used terms. May
be the reason is that the term “adaptive” is not a univocal word. However, another finding is that there
is more attention is given to the related used terms and their definitions from researchers than the
concept definition itself. While Chloë Marysse considered that these terms are alternatives to the term
“adaptation”, Marta differentiate between them. In fact, from research point of view, in line with
Marta’s approach, the terms are different and they need attention to identify the associated functions
to each term. This can lead to better understanding and potential for maximizing the benefits of
developing the concept in building design.
Reference to Michael and Harris, they count more than 30 terms used to describe this façade concept.
These terms are different in use and not all of them are alternative descriptions (Michael Wigginton
and Jude Harris, 2002). In general, the terms used could be based on the two definition approaches
(mechanical and/or material systems) or used to describe both. They may be defined as following:
1. Interactive: A systematic approach term could describe both mechanical and/or material
systems. It related to computational aspects of building systems. This term is used more often
in feedback-based design. It involves human input to gain the system output. Frequently, the
term is used in reference to computer-enabled artworks, installations and other such
environments encouraging active public participation. There are increasing number of facades
around the world featured this concept (Velikov, K., & Thun, G., 2013). The term associated
with concepts use controllers, sensors and actuators to interact.
2. Smart: Commonly used to describe the properties of material, surface and less use for systems.
Even though, nowadays the term is widely used by people due to the notion of smart devices
(smart phones, watches…etc.). Therefore, when it used in building industry it refers to highly
sensitive technologies that able to response in real-time bases to occupant or operational
requirements. The embedded properties could respond to one or more boundaries attributes
without sensors, controller or even actuators. On other hand, the term sometimes used to
describe sort of integrated systems that perform together to achieve specific performance in
certain conditions.
3. Intelligent: The term “intelligent” has been used extensively in the construction industry since
building automation and telecommunications became more pervasive in the 1960s and 1970s
(Velikov, K., & Thun, G., 2013). It is stimulating the futuristic sense of people imagination as
it is linked to the artificial intelligence era. The term might describe the façade material but
usually used for various systems that are able to work together with minimal human control.
Intelligent envelopes describe building systems that have various levels of responses and able
to react in different modes based on the inputs which been analyzed by computing systems.
High intelligent systems could predict the required responses on certain conditions without
human control. Researches use this term widely as it has a broader notion. The European
Intelligent Building Group defined the intelligent buildings as: “building that ‘incorporates the
best available concepts, materials, systems and technologies. These elements are integrated

20
together to achieve a building which meets or exceeds performance requirements of the
building stakeholders. These stakeholders include the building’s owners, managers and users
as well as the local and global community” (Wigginton and Harris, 2002).
4. Responsive: General term used to describe any façade systems that able to react based on
contextual changes. Its limited to facades that need an act to react. The responses could be
changes on material property or a mechanical system action. Responsive facades may employ
sensors and actuators or be controlled by human inputs to define the required responses. The
term is commonly used to refer to RBEs responsive building elements. RBEs represent the
latest generation of e.g. smart technical systems and smart materials (Gosztonyi, 2015)
5. Deployable: More related term to structural system and refer to the type of prefabricating the
façade components. Deployable also, describe elements that has an initial state and structurally
can be deform by sort of fabrication mechanism to another final state. The term is confusing
when it compared to the “transformable” term. (Marysse, 2016).
6. Convertible: Similar to the structural systems terms, this term describes the elements that able
to change from state of form to another. “Convertible” is more linked to elements than whole
façade concept. Elements able to change its shape to function in another shape “two different
functions” are convertible elements. Other term aspect is that it possible to identify two types
of convertibility: external, i.e. the variability of the external envelope of the building, and the
inner convertibility, related to the interior spaces. Convertible systems are designed to change
their form in relation to the needs and in a short time (Marta Barozzi et al., 2016).
7. Retractable: Referring to the façade structural system, the term is commonly used in
architecture for textile membrane roofs in which the membrane is bunched or folded. As a
simpler expression, such systems are also referred to a movable features or components (Marta
Barozzi et al., 2016). “Retractable” is most likely façade components more than describe the
façade itself.
8. Transformable: Another structural terms, similar to convertible, transformable can be
associated to objects or structures which have the intrinsic property of controlled change.
Transformable bodies can be foldable, retractable or shape shifting (Marta Barozzi et al., 2016).
The transformation process goes from a compact to an expanded configuration or backwards.
The transformation phase needs to consist of controlled, stable movements and results in a rigid
and secure structure, once it is locked in place with consideration of the time aspects of the
transformation process (Marysse, 2016).
9. Dynamic: One of the most frequently used terms. Describes the responsive façade from
mechanical system perspective. Dynamic Facades have the ability to response in frequent bases
(small time scale). Façade’s dynamic elements could be controlled automatically or/and human
inputs to act based on the context conditions or the operational requirements. The term has a
mechanical concepts and refer to the forces caused the dynamic action. Dynamic object has
initial state and temporary state (the response state). On other hand, the term could be used to
describe a statically façade (from mechanism perspective) while it has sort of dynamic form
(from aesthetical perspective), for instance, parametric envelop design patterns and dynamic
fluidic architectural masses (Deconstructionism, e.g. Frank Gerry and Zaha Hadid Architects
work examples).
10. Kinetic: Kinetic Facades consist of several integrated material or/and mechanical systems
which are reacting under certain conditions. Kinetic, originally, is a mechanical term used to
describe the movement laws of masses with appreciation of forces and time consumed. If the
cause of system motion is an elastic deformation the system falls under the category of Elastic

21
Kinetics (Marta Barozzi et al., 2016). However, the term is commonly used regardless the
structural and mechanical states of the facades. Sometimes, it’s used in association to the
multimedia façade designs.
11. Adaptive: In addition to intelligent, dynamic and kinetic terms, the “adaptive” is another
frequent common used term in this regard. It means the ability to adjust and adapt to changing
circumstances by itself. Adaptive envelopes have the capability to change their behavior,
features or configurations in relation to external variations (Branko Kolarevic & Vera Parlac,
2015). This research is titled using this term as it represents the structural, mechanical and
material properties ability to adapt either to respond or to initiate the act (not limited to the
reaction behavior) to meet required criteria, performance or defined state.
2.2.1 The associated terms
At the end of the definition review, it has been found that there are few terms used in association to
the adaptive building concept in relation to the exterior fabrics. Shell, enclosure, skin, façade and
envelope are used to describe the exterior features with these active properties. While these terms seem
resemblance or synonyms, they have different limitations to define (Marta Barozzi et al., 2016).
The term “shell”, is to describe the building exterior planes that covers and protect (Yu, 2014)
commonly used as a general term or for structural aspects. Shell could be used for structures that have
no space underneath or built for outdoor or urban landscape purposes while “enclosure”, is a shell that
has occupied space to protect and cover (Wigginton and Harris, 2002). “Skin” is used to describe the
concept of the outer layer from the building enclosure interferes the outdoor conditions. To reinforce
this tendency, Wigginton and Harris in their book Intelligent Skins stated “the skin operates as a part
of a holistic building metabolism and morphology, and will often be connected to other parts of the
building, including sensors, actuators and command wires from the building management system”
(Wigginton and Harris, 2002).
For aesthetic aspects, the term “façade” is commonly used. It describes the visible planes from exterior
and interior perspectives. “Kinetic Facades” frequently used by building designers to describe the
adapting strategy of the design. “Envelope” recently, has more widespread use as it describes the
building containment planes. Either these planes are facades, roofs or canopies. Also, it is extendable
to cover all exterior fabric or construction layers with no limitation to the outer layers (skin) or the
structural perspective (shell).
2.2.2 Proposed definition
To conclude the concept definition and used terms review, this research attempt to define the concept
from more holistic approach. The Adaptive Building Envelopes could be defined (or described) as:
Envelopes that are able to adapt by responding to contextual conditions’ attributes, either indoor or
outdoor, natural or man-made, related to the building occupants or the community, this adaptation
allow the building to perform better by achieving a defined criterion. The term “adaptation” is meant
its materials physical properties or manner (e.g. intelligent and phase change materials), shape and
appearance (dynamic and transformable façades), color, image or texture (e.g. media active facades)
or composition of several integrated active systems (kinetic façade).
The definition is associated with term “Envelop” which limits the concept to the external planes of
building’s enclosed spaces (air-conditioned, semi air- conditioned or naturally ventilated spaces).
Either these planes are horizontal, vertical or inclined (extendable term to cover building’s roof,
canopies and semi-indoor spaces).

22
Factors influencing and benefits of adaptive envelopes
Exploring the aspects of the concept definition lead to the area of identifying the factors inspiring the
responsive façade in a specific situation (why do we need adaptive envelopes…?) and then, defining
the potentials from considering this strategy (what are the targets to be achieved by this adaptive
strategy…?). The first one shaped by the case contextual attributes, either they are natural or man-
made factors, interacting with the building. While the second, is the targeting performance from this
adaptive envelope.
Figure 2-9, Illustration presents the relation between design attributes and envelope design. The adaptive envelope provides a two-
directional relation while the static façade preserves its state under all conditions
2.3.1 The contextual attributes
To answer the first question (why do we need…), examination of the researchers’ views showed that,
they appreciate the environmental and climatic factors or energy performance concerns only. For
instance, Riham has limited the attributes influencing the dynamic facades to sun control, natural
ventilation, daylighting, connection to outdoor, thermal insulation, moister control, structural
efficiency, possibility of energy generation and material choice (Nady, 2016). Nevertheless, she
extended the attributes more than Loonen who considered the climatic based design parameters are the
drivers for the adaptation behavior. His exclusion justified by considering that other trends have
subjective objectives which difficult to be quantified into performance model at the next step of the
design process (R.C.G.M. Loonen et al., 2013). Other researchers agree with Loonen approach
considering the climatic based and energy performance design are the key solutions for the
environmental concerns (Aksamija, 2013).
The research’s approach to study the adaptive concept holistically classifies the contextual attributes
into six categories. It is considered as a part of the research findings. This classification will support
developing holistic performance model taking into account all context aspects. The relation between
these attributes and envelope design is critical to understand how they can motivate the concept. The
attributes’ categories priority will vary from case to another.
There is a considerable relation between each of the attributes and the others. They can influence or
impact the performance in a direct and indirect way. The attributes should be weighted relatively to
measure their contribution into the envelope design. The six categories of design attributes are:
Static
Envelope
Adaptive
Envelope
Static / Steady State
Performance
Static responses to the attributes based on an
initial building design with limited possibility
to consider new requirements
Responsive / Dynamic
Performance
Optimized responses to the attributes based on an
initial design that considers the contextual changes
possibility
Design
Attributes

23
Figure 2-10, Basic design contextual attributes which influence the design objectives and envelope performance model
1. Owner Program and Building Functions: The primary goal of any building is to function
properly. Spaces have different functions require different conditions to operate efficiently.
Thus, envelopes role to maintain the functionality is the heart of its performance model. While
work, study and residential spaces require certain levels of daylighting, commercial and
healthcare spaces are most likely on the opposite side. This in addition to the operation periodic
scale. These aspects should be determined to define targeted envelope performance which will
vary from space to space and from time to time. Subsequently, responsive behavior should be
considered to fulfill the required function.
2. Climatic and environmental conditions: Climatic-based envelopes are a dominate trend due
to several reasons. The climatic and environmental conditions had a highly dynamic pattern
changes along time scales (hour, day, season up to full year). These conditions are stimulating
designers to get the benefits that support envelope performance by regulating air and light
through building skin layers (Aksamija, 2013). However, this is not the case all the time as
these conditions require a protection (level of insulation) role from envelopes most of the times.
The climatic adaptive pattern has typical changes that can be predicted and models could be
established accordingly to define the major aspects of climatic conditions and their periodic
pattern along the time scale:
- Level of heat and moister insulation.
- Desired amount of daylighting.
- Wind speed and natural ventilation possibilities.
3. Occupant behavior: While both of the previous two design attributes can be predicted and
performance model can be developed accordingly, occupant behavior seems to be different for
certain level. The interaction between occupants and buildings envelope is commonly related
to achieve comfort levels which is relatively defined. The comfort level itself could be adapted
and changed with time. Additionally, occupants adapt the spaces to match with their needs.
These sort of relations are influencing the adaptive design and impact it (Aksamija, 2013).It is
crucial to consider occupant’s behavior and scenarios for attitudes to establish reliable
performance model. This attribute has no quantitative parameters to measure unless it is
considered from climatic point. However, it is not that only aspect of the occupant relation with
envelopes.
Owner Program and Building
Functions
Building function and program
Climate and Environmental
Conditions
Daylighting, solar gain, wind, humidity… etc.
Urban and Culture
Interaction between envelop and community to
enhance image, social network and local culture
Occupant Behavior
The human factor, how occupants will behave
and interact with building systems and
envelope functions
Engineering and Technology
CTRL, maintenance, utilization,
Economical Aspects
Construction and fabrication cost, cost of
energy and utilities, maintenance cost,
revenues and the reuse cost
Design
Attributes

24
4. Economical aspects: In general, the adaptive envelopes are not a cost effective solution for
most cases in short term level (Fortmeyer and Linn, 2014). However, they show a sufficient
savings in energy costs in long term level. The capital and running costs are prime attributes
for each built case. Adaptive envelopes trends are usually associated with higher technologies
which have a higher capital costs than static envelopes. Envelop performance models have to
address certain cost aspects before defining the adaptive strategy:
- Building capital cost per unit area for similar cases (benchmarks)
- Envelop capital cost per unit area for similar cases with static performance or regular
designs (benchmarks)
- Running cost rates due to energy consumption, resources use and maintenance.
- Accumulative analysis for building costs after mid of its anticipated life space
Then a comparative analysis is undertaken to compare different strategies financially.
Therefore, reasonable adaptive strategy could be employed. In some cases, it might be useful
to examine the reuse costs. This attribute has no variable values related to building performance
while it is one of the prime parameters to be defined due to the course of design.
5. Urban and cultural aspects: The contextual attributes outside building perimeter are
considered as part of Building-Eco effects. Envelopes can either influence or impact the urban
and social aspects. It is noticed that buildings employed some adaptive envelope strategies
(while it can be visually noticed either from outside or inside) have social values in their
communities (Fortmeyer and Linn, 2014). In addition, envelopes can feature adaptive media
features for advertising and find a sort of integral interfere between building’s and society. This
strategy compensates the drawbacks from the fourth attribute; the economic aspects, as it could
generate revenues.
6. Engineering and Technology: The availability of technologies and its practicality to be
functioned in built-environment is a key consideration to define the reliable and achievable
adaptive performance model. Most of adaptive envelopes’ strategies are associated with
recently developed technologies or smart materials still are under experimental studies to
examine their performance in different conditions. In addition to that, new trends become
available everyday allowing for more efficient solutions have potential to adapt and considered
in design.
Reviewing these attributes and from influencing and inspirational perspectives, it has been found that
the second and the fifth ones are the most frequent ones to influence the concept of adaptive envelope
design. The sixth and the third are following these two as prospective influencers. While the first and
the fourth are concerns should be considered from performance point. These design imperatives have
a direct connection with the concept typology and trends. The concept is often being developed to
generate envelopes of dominance response to one of these attributes while performing efficiently on
the others (or at least up to an acceptable level of performance).
2.3.2 Envelope performance model
The ultimate goal from employing an adaptive envelope is to improve the performance while
maintaining (if not enhancing) the aesthetical aspects of a building. Envelope’s performance is a
fundamental step to define the adaptability criteria and required systems accordingly. The hierarchy of
this performance modal is vital in this occasions to take proper decisions and subsequently, an
exceptional performance can be achieved (Kesik, 2016). It is usually linked to as engineering criteria,

25
sustainability aspects and energy targets. Architects, engineers, energy and sustainability experts
should engage at early stage to define these performance metrics. It might be required to have wider
team including cost consultant and facility manager to develop detailed models which should be
established based on deep understanding of the contextual attributes and applied throughout the
following levels:
▪ Definition level: to identify the key aspects of required performance and their breakdown (e.g.
Hydrothermal performance - heat exchange…etc.)
▪ Then, determine the metrics of performance parameters based on achievable and reliable
benchmarks (e.g. determine the R-Value throughout the operational time scale). Then examine
different adaptability strategies up to achieve the defined aspect and the determined metrics
“performance targets”.
▪ Along the path, the model is used as a reference to monitor, and guide the process throughout
envelop design, construction and operation activities to achieve the targeted metrics.
Figure 2-11, Building performance modal (Kesik, 2016). The hierarchy pyramid presents the priority of each building performance
aspect
Developing an adaptive envelop
Examining the design and execution process of an adaptive envelope showed that there are few
methodologies could be considered. Most of these methodologies are based on a computational design
process to calculate and simulate the performance due to initiating the construction process which has
several testing tasks to ensure the design aspects before final fabrication and installation.
There are significant attempts by researchers like Shady Attia who has mapped the process into twelve
phases (S. Attia & H. Bashandy, 2016) while others like Abdulmajid Karanouha and Ethan Kerberb
considered it as a part of a normal practice of project –building process (Abdulmajid Karanouh, and
Ethan Kerber, 2015). The first approach, considers the adaptive envelope as a unique feature has its
own execution process (even though it is integrated with the design and construction processes) in
contract with the second one which deal with the adaptive envelope as a “complex” building
component to be designed and executed as part of the whole process with some special requirements.
Assessing the same case study; Al-Bahar Tower, Abu Dhabi - United Arab Emirates, 2012 by Aedas
Architects. Both of the two approaches considered the integrated design process (IDP) as a
`
Image,
Occupant
Comfort
& Well-being
Durability, Economy,
& Environmental Impact
Hydrothermal
Performance
Fire, Structural, Strength & Rigidity
Aesthetics
Aesthetic considerations may be applied to building envelop
alternatives that satisfy the preceding criteria
Sustainability
Hydrothermal performance, along with the selection of
materials and methods, influence sustainability
Environmental Separation / Moderation
Control of heat, air, moisture and solar radiation passively
influence the quality of indoor environment
Health and Safety
Minimum requirements for health and safety represent a
necessary but insufficient condition for high performance
Hierarchy of Performance Model key aspects

26
fundamental requirement for the work environment to succeed (Karanouh, and Kerber, 2015). They
agree as well about the importance of the assessment and testing phases along the execution process.
In Shady’s assessment of this particular case, he has highlighted the vitality of the iterative approach
considered by the project team (Attia, 2017). In contrast, he showed sort of criticism to other Case
Study of AGC Headquarter in Belgium. The second case was developed in a linear flow controlled by
the architect during the design phases. This one-way process impacted the construction phase which a
façade and energy engineers showed a concern about the material selection by architect (S. Attia & H.
Bashandy, 2016). Shady has divided the process map of the integrated design process in Al-Bahar
Towers into eight phases. While he has considered six phases for assessing and testing the adaptive
envelopes.
Figure 2-12, The process map developed by Attia for Al-Bahar Adaptive case study consists of eight phases of execution
Figure 2-13, The assessment map developed by Attia for testing the adaptive envelopes consists of six phases
Abdul Majid, who was a key person in developing this particular significant case, has emphasized the
importance of considering other process aspects (Karanouh, and Kerber, 2015). His list includes the
following vital issues:
› The CODE design, which generated to define the algorithms of kinetic features geometry and
to link it with its behavior,
› Time-tested simulation studies to ensure the performance validation,
› Manufacturing mockups followed by on-site mockup tests before installation process (a full
integrated façade unit, which assembled part of the building’s facade demonstrates the
realization of the CODE principles.).
In addition to these issues, he has considered the team integration and defining a common design
language between different stakeholders as one of the main challenges to develop an adaptive design.

27
Attempts for classification
During the last three decades, adaptive envelopes were a fertile subject for researchers. Several
attempts to study and analyze the notion and its typology have been carried out. The classification of
the adaptive strategies is vital to differentiate and identify the relationship between them. This could
help in developing and integrating adaptive systems in future. Reviewing these attempts, it has been
found that the concept typologies often based on one of the following criteria of classification
(sometimes more than one):
› Technologies or controller-based methods,
› Status-based strategies and physical properties,
› Structural-based strategies,
› And theme of adaptation-based strategies: inspirational background, time and scale of
adaptability (micro and macro).
In addition to these criteria, the nature of sensors, controllers or processors and actuators as adaptive
systems features, considered to differentiate between different adaptation methods. These levels of
reaction process could be intrinsic of martial physical properties, automated systems, or human-made
(hand-operated system).
There are several significant attempts of classification. Loonen’s, 2013 attempt, he classified the
concept based on various criteria. Each criterion considered as an independent approach for classifying
the concept trends. Moreover, a trend could be rooted to two or more of these classifications. His
approach bases were: (a) the sources of inspiration, (b) relevant physics, (c) time-scales, (d) scale of
adaptation, and (e) control types (R.C.G.M. Loonen et al., 2013). Later on in 2015, he developed a
unified and systematic characterization to category the adaptive envelopes. This time he based the
classification into several criteria to shape a matrix of eight descriptive characterization and criteria of
adaptive facade concepts for facade adaptability after comprehensive review of other attempts
(Loonen, Rico-Martinez, Favoino, Brzezicki, Menezo, La Ferla, Aelenei, L. (Laura), 2015). However,
all his attempts are limited to the CABS concept only (climatic Adaptive Building Shells) with no
consideration of other adaptive strategies.
A wider classification has been developed by Radwan. His functional approach came up with three
main strategies: (a) intelligent facades, (b) kinetic facades - responsive building skins, and (c) media
facades (Radwan, 2016). This attempt is based on control methods and physical properties of façade
elements. Another significant attempt by Susan who has classified the adaptive concept based on more
general criteria than Radwan’s one. Her approach is based on two key pillars; the materialization of
the system (materials or/and mechanical system) and the processing of information through the system
to act on adaption (sensors technologies). These two pillars leaded her classification into two main
categories: (a) operational or functional model describing the performance behavior, and the b)
magnitude and order of adaptation measures influencing the design (Gosztonyi, 2015).
The technology-based classification by Negar, has studied twenty-nine systems which are substantial
representation of existing responsive facade systems. These systems are classified based on their
criteria for system control, sensing, actuating, material and structural technologies (Negar Heidari
Matin, Ali Eydgahi & Shinming Shyu, 2017). The technological-based classification results five
strategies which are: (a) mechanical technology, (b) electro-mechanical technology, (c) information
technology, (d) material-based technology, and (e) passive technology. This classification proposed
and integrated technology strategy which can be mixed between these strategies as a hybrid theme.

28
Figure 2-14, Loonen's matrix of descriptive characterization concepts for facade adaptability. Ref Loonen’s, 2015
Figure 2-15, Reference chart from Negar classification attempt. She considered the technology-base as a classification criteria to
define the adaptive envelopes typology (Negar Heidari Matin et al., 2017)

29
Proposed taxonomy of adaptive design strategies
This research has abroad approach towards building envelopes design. While the aforementioned
attempts have a climatic and environmental background which limited most of them to the climatic-
based design facades. This research is not a sustainable or energy study on façade design trends. In
fact, it is an attempt to explore the adaptive envelopes concept as it is one of the future trends which
will influence the built-environment. A proposal for broad typology of adaptive envelopes has been
developed and summarized here while it has discussed in details at section 4, the findings and
recommendation of this research. The following chart outlines the research proposed taxonomy:
Classification bases and examined aspects Classification of the adaptive enevlopes design
strategies
Figure 2-16, Illustrative chart presents the summary of the taxonomy bases and criteria which resulted five adaptive design strategies.
This finding proposal will be discussed further at section 4 as part of research findings and recommendations
Objective
& functionality
Relevant physical nature
of the adaptive feature
The adaptation
technology and control
method
Scale of adaptation
Time scale
Taxonomy
of
Adaptive
Strategies
Passive
Strategies
Living
Enevlopes
Intelligent
Skins
Active
Strategies
Kinetic Enevlopes
Media
Facades
Transformable
Architecture

30
Section Summary
The historical background of the adaptive building envelopes shows that the concept has been
developed through many generations result in highly sophisticated techniques along time through
involving more advance systems to satisfy more complicated requirements. This historical review is
an indicator to researchers that shows how concepts were evolved and developed, as well as the success
keys, reasons of failure and what are the lessons learned from all of that.
The literature review of the adaptive envelopes showed that, the adaptive design concept definition is
underdevelopment area of building science. While there are significant attempts by researchers to
define a frame of work, most of these efforts are an environmental and energy driven studies resulted
limited findings to this area of the AEC industry. The research proposed a holistic concept definition
to extend the boarder to its nature “buildings of responsive behavior to an external condition”. Which
followed by discussion upon the design attributes influencing the adaptation and model to measure the
performance. An Additional discussion upon the process of employing the concept into buildings.
Finally, the section ended by a summary of the developed taxonomy of the adaptive design strategies
which will be detailed at later stage as a core output of this thesis.

31
3. Case Studies
The objective of this section is to examine the practice of the adaptive envelopes design. Based on the
developed taxonomy, the research suggested five basic strategies could be employed in envelope
designs. The case studies which have been selected to reflect this classification, have been studied in
accordance to the research methodology of studying the concept. Means that for each case, the design
attributes and targeted performance are investigated before discussing the envelope techniques. At the
end of each case, research puts notes into the design technique, process, challenges and success keys.
Then, the study closed with findings of the case.
The practice of the adaptive envelope design around the world
Although there are a few built cases of adaptive envelopes among the building stock worldwide, there
is a significant increase and demonstrated interest of the adaptive envelopes field. The growing number
of researches to explore the concept aspects and develop it for future use assuring that the built cases
will grow rapidly in the coming few decades. Communities sustainable agenda, energy and resources
prices and human centered design trend are paving the road to have an adaptive built-environment in
future. To serve this interest, several researchers and professionals networks are established to share
ideas and experience on the field. One of the leading examples is the Adaptive Façade Network, Europe
- COST Action TU1403. In addition to the educational platform, there are several professional
networks like FACE and ZAK World of Façade.
During the 20th
century, the construction industry has been transformed due to the computation of
things. To compromise the cost implications and risks associated to employ an adaptive concept, it
requires a high level of performance simulation and experimental studies to ensure the efficiency of
the design. Advance building modeling technologies and BIM (Building Information Modeling),
logarithms and parametric design, scripting and JAVA technologies and last but not the least the
Micro-Electro Mechanical System (MEMs) all are influencing the trend by more accurate design based
on achievable performance models. Moreover, the increasing knowledge of human comfort and
occupant behavior are supporting the design efforts by reinforce the consideration of the human factor
into the design process.
Figure 3-1, Illustration represent the
contribution of the high-technology
modeling and building modern science to
the adaptive envelope design.
Adaptive
Envelope
Design
BIM
&
Advance
Modeling
Logarithms
Design,
Scripts, and
JAVA
Occupant
Behavior &
Comfort
Science
Simulation
Softwares

32
Cases examination method
To serve the purpose of the case studies scope within this research, the selection of the cases is based
on the adaptive envelopes typologies on the way that allows to compare and contrast in both qualitative
and quantitative aspects between trends. Therefore, consolidated views into the practice can be shaped.
The case studies methodology passed through several phases to conclude the findings.
Figure 3-2, Illustrative chart of the case studies methodology
As part of the examination method, selecting a case has passed through the following selection criteria
to ensure the vitality of the outcomes from the study:
1. The purity of strategy implementation. To study the performance of a specific adaptive
strategy, it is vital to select cases that considered mainly one strategy (not hybrid design) so
that it can be studied and evaluated.
2. The date: recently developed cases are preferred including sometime of operation. Hence the
performance can be evaluated and may post occupancy feedback be available.
3. Built cases “real cases”, to ensure the practicality of the design and the consideration for various
project contextual attributes.
4. The geographical and climatic conditions: various conditions lead for approaches verity and
enrich the used methods.
5. As much as possible, fresh cases that have not previously studied while have significant
contribution to the research field.
Based on the proposed taxonomy of adaptive strategies, which proposed five strategies of adaptive
envelopes (ref to Figure 3-3, The Hierarchy of adaptive envelopes taxonomy). The classification will
be discussed on details (section 4) in light of the case studies findings. These case have been selected
in order that each strategy has a significant case to study the practice of its theme and in same order of
the classification. The findings at the end of each case are summarized and related to the case and the

33
used strategy even if the case doesn’t reflect all of this findings. The case studies contribution to the
research knowledge requires digging more in the practice field to identify these findings.
Figure 3-3, The Hierarchy of adaptive envelopes taxonomy and the selected case studies
Adaptive Envelopes
Passive Design
Strategies
Living Envelopes
Bosco Verticale,
Milan
2011 - Spain
Intelleginet Skins
HygroSkin -
Meteorosensitive
Pavilion
2013 - Germany
Active Design
Strategies
Kinetic
Envelopes
Manitoba Hydro
Place
2010 - Canada
Media Facades
Mega-Faces
2014 - Russia
Transformable
Architecture
Sharifi’Ha House
2013 - Iran

34
Case Study – 1, Bosco Verticale, Milan
The selected living envelopes case study is Bosco verticale, which has been titles as “the 2015 Best
Tall Building Worldwide” at the 14th Annual CTBUH International Best Tall Building Award
Symposium. The project employed more than 13,000 plants across +90 species, including full-sized
trees, on all facades of both of its towers which is the most intensive ever realized living facade
(Giacomello, 2015). Towers of 117 and 85 meters’ height treated by vegetation design enabled the
building to breath, deform and grow.
3.3.1 Case overview
Project: Bosco Verticale,
Location: Milan, Italy
Date: 2011-14
Team: Architect: Boeri Studio, structure:
Arup - Italy, MEP Engineer: Deerns
and Main Contractor: ZH Construction
Company S.p.A. Other Consultants
Deerns (LEED consultant & vertical
transportation), Boeri Studio (landscape
designer), Studio Emanuela Borio
(landscape designer)
3.3.2 Context and design attributes
The contextual attributes have derived the
design and influenced the adaptive envelope
strategies featured in this unique case.
Owner program and building functions:
Both of the owner “Fondo Porta Nuova
Isola” and the developer “Hines Italia” are
key factors influenced the project through
their vision to build a unique residential
property. Project team, including structural
and engineering firms, has dealt with this
vision carefully to develop the proposed
vertical forest concept by the project
designer.
Environmental and climatic conditions: The site climate classified as warm temperature with fully
humid, hot summer (Elena Giacomello & Massimo Valagussa, 2015).
Occupants: Two residential towers. It contains 400 condominium units priced from 3,000 - 12,000
Euro per square meter. The rate gives indicator about the high level of the resident’s lifestyle.
Economical aspects: Porta Nuova area urbanization project was approved in 2004 and available
surface was arranged for radical urban transformation, comprising an investment of more than 2 billion
Euro (US$ 2.51 billion) to create a mixed-business and residential district. There is no available
information about the cost of the two towers nor the adaptive strategy costs (Branko Kolarevic & Vera
Parlac, 2015).
Figure 3-4, Aerial view of Bosco Verticale after occupation
Figure 3-5, Photo of the design architect during the concept
presentation with the developer

35
Urban and cultural aspects: The Bosco Verticale is part of the new Porta Nuova area, an extended
urban transformation of a neglected area of Milan. This 34-hectare area is completely new; before the
construction of 20 towers in the last decade, it was one of the last unbuilt sites in the city. Before the
Porta Nuova project began, the area was partially occupied by an amusement park; much of the
remainder was abandoned and vestigial land.
Figure 3-6, A sequence of google images show the urban context deformation and how it has been evolved into more greenery
urbansim within less than 20 years
Engineering and Technology: The project has a limited influencing by the engineering and
technologies. The modern bio-climatic studies of the spices helped to develop this exceptional solution
mixes the architecture with agriculture in form of vertical forest. The technologies in this case were
employed to serve the design more than influencing the adaptation concept as a design driver.
3.3.3 The adaption technique
The biodiversity of the building’s living envelope is considered, by the architect, a new approach for
sustainable tall buildings design. The vertical forest replaces traditional materials on urban surfaces
using the changing polychrome of leaves for its walls. The biological architect relies on a screen of
vegetation, needed to create a suitable microclimate and filter sunlight, and rejecting the narrow
technological and mechanical approach to environmental sustainability. Additionally, the project
contributes to the city eco-system in shape of vertical green separator allows for various spices
including birds and insects to be inhabited (Archdaily, Bosco Verticale / Boeri Studio, 2015).
Figure 3-7, The concept of naturally adaptive polychrome of leaves provides aesthetical, social, and climatic solution

36
The vertical forest helps to build a microclimatic barrier which filters the environment and turns the
city into a more sustainable urbanism. Nevertheless, this microclimatic barrier supplies the towers’
residents with a fresh air, nice views while maintaining the privacy, produces oxygen, and protects
against radiation and noise pollution (Elena Giacomello, Hines Italia, and Boeri Studio, 2015).
Bosco Verticale is covered with more than 18,000 square meters of living green facades deploying
13,000 plants across +90 spices including full-size trees and green-walls. There are 700 trees of six
meters high, shrubs, and flowering plants. The collection is carefully selected to provide a dynamic
image changes in various seasons. The choice of species and their distribution according to the
orientation and height of façades is the result of three years of studies carried out alongside a group of
botanists and ethologists. Considering the different microclimatic conditions per each building side,
floor height along different timing. The plants which are used on the building were pre-cultivated in a
nursery in order for them to become accustomed to similar conditions to those which they will find on
the balconies (Archdaily, Bosco Verticale / Boeri Studio, 2015)
Figure 3-8, Illustrative architectural study of the micro-climatic
conditions of the envelope provided by the vertical forest
Figure 3-9, The vegetation strategy of employing different
planters size
Developing a feasible structural system to load the vertical forest is a vital aspect of this case study.
The plants load, soil, irrigation water, insulation wind loads are unusual structural challenges for such
tall buildings. Moreover, the concept features a cantilever terraces of 3.30-meter depth and free corners
of 7.00-meter with no supports which result more loads lead to post-tensioned reinforced concrete
floors. Linked to the structural system is the restrain system which provide three protections against
falling trees; these are temporal bind to fix the tree roots ball into the soil, basic bind to fix the tree
from three different directions, redundant bind as additional root fixing to the tree in the windiest sides
of the building.
The irrigation system has been developed to consider the various plants requirements, environmental
conditions, and the plants location from the building facades thus a proper amount of water to be
delivered to each tree.

37
Figure 3-10, Structural skeleton image of the cantilever terraces Figure 3-11, Conceptual structural detail of the tree containers
shows the post-tensioned slabs, tree pots, and proofing
Figure 3-12, Different restrain system binds to ensure the resilience of the vertical forest against wind. Additionally, to protect plants
from un-controlled growing patterns
Figure 3-13, Illustrate presents the concept of the irrigation system of various project greenery features

38
Another critical point in this living envelope case study is the plants care and maintenance. Throughout
the year during various seasons the plants require a special care to maintain the shape, monitoring the
growth and protect against harmful insects and diseases. Maintenance strategy relies into two ways;
the first is to get accessed via apartment. It is expected to be 3-6 times per year. And the second is
through basket-lift allows access from outside. The basket-lift moved by telescopic arm placed at the
roof top of each tower. The pruning and other maintenance which has to be done by this way could be
done 1-2 times per year. The innovative use of heat-pump technology is helping to slash heating and
cooling costs (Giacomello & Valagussa, 2015).
Figure 3-14, Images show the basket-lift man during the regular plants maintenance
3.3.4 Design methods and tools
While, usually, the design team of building features an adaptive envelope consists of architects and
engineering’s with different specialties, the living envelopes design requires botanists and
horticulturalists to aid and support the selection and the engineering of the design itself. Therefore, the
landscape design role in this particular cases is vital to have a wealth plants that can last longer.
Additionally, the structural concerns from the loads and the resilience of the plants required a wind
tunnel test to ensure the trees will not topple from gusts of wind. Maintenance contractors have been
called for consultation during the design process to ensure the feasibility of the access and maintenance
methods.
During the construction, the installation of the plants has involved special tests to ensure the efficiency
of the irrigation and plants monitoring systems. The plants have been nursed at the construction site to
feel the conditions of their future home due to installation.
Figure 3-15, Images show the installation process of plants

39
3.3.5 Findings
This vertical forest concept provides an exceptional adaptation design. The natural interaction pattern
results an almost free organic form of adaptation along building’s life span. The living facades which
finally constructed with around - both two tower - 730 trees (480 large, 250 small), 5,000 shrubs, and
11,000 perennials and groundcover shaped a role of an active interface with the environment.
The case showed different aspects of the living envelops treatment. Generally, the design process went
through normal design project workflow with an attention to the vegetation aspects. The construction
and execution involved plants nursery on-site which replaced the mockup and testing tasks in addition
to the special installation of the vertical forest. Moreover, project team and stakeholders included
specialists and maintenance advisor from early stages of the design.
The concept of green-walls has critical aspects that have to be considered and carefully designed in
most practicality:
› Plants: types, diversity and biological interaction between various types. Native plants are
preferred to use to minimize the associated risks and to maintain the biodiversity of the
ecosystem.
› Planting media and how it can be maintained to support the organic processes.
› Structural system that supports and attached the plants to the façade.
› The irrigation system, concepts utilizing greywaters shall be balanced between the amount
of treated water and required water for irrigation to avoid the excessive use of watering.
› The maintenance and plants care strategy feasibility and practicality to ease the operation.
› The running cost of plants care and maintenance should be part of the concept feasibility
at earlier stage as possible.
› Occupants have to be educated about how to care and maintain their potential gardens.
The positive findings of the concept are summarized on the following:
› Bosco Verticale living façades have a significant contribution to city urban image
transformed the case into a city landmark. In same time, the society has been leaded by
example by the case to appreciate the biodiversity of the ecosystem and the role of
vegetation to improve the built-environment.
› The active interface with the environment will play a broad role to include biodiversity as
an element of environmental enhancement. However, the full understanding of the impact
of this design will occur in the future through the transformation of the eco-system.
› The excessive vegetation helps to improve the external environmental conditions, such as
air temperature, mitigation, air humidity, absorption of dust, reduce pollution and biogenic
volatile organic component production. The benefits are extended beyond the building
boundary to the urban context.
› For the internal environment, the concept helps to reduce cooling loads as it minimizes the
solar heat gain through the envelope. Plants sunscreen modulate the heat transfer while
produce natural shading. The leafs help to reduce the convective heat transfer while they
process the transpiration and photosynthesis subsequently reduce air temperature.
Additionally, the plants reduce the noise and air pollution transfer into the indoor.
› Occupants mental health, well-being and health are improved due to the natural mitigation
throughout their living spaces along their daily activities. Provide a private elevated gardens
supports the lifestyle of the residents.

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On opposite side, there are challenges facing the living envelopes concept associated with the
following factors:
› The vegetation resilience, trees age and durability of the living system to match the
buildings life spans (30 – 40 years). Possibilities of major replacement two or three times
along this period.
› Extra capital costs associated to the waterproofing, containers load and structure and
irrigation system especially in tall buildings.
› High running costs due to the plants care and maintenance requirements (timing,
workmanship qualification, spare plants, potential infect by insects and diseases and
seasonal vegetation lifecycle) in addition to water and energy consumption to supply plants
with water and maintain the best living conditions.

Developing Strategic Framework for Adaptive Building Envelopes

Developing Strategic Framework for Adaptive Building Envelopes

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