Philippe Samyn - Between light and shade

philippe sa m y n

BETWEEN LIGHT AND SHADE

Aca démie roya le de Belgique Se r ie s p o c k e t b o ok ac a de m y-

BET W EEN LIGHT A N D SH A DE , T R A N S PA R E N C Y A N D R E F L E C T I O N

by the same author La ville verticale, Brussels, Académie royale de Belgique (“L’Académie en poche”, 38), 2014 (reprint 2017).

The Vertical City, Brussels, Académie royale de Belgique (“L’Académie en poche”, 38-EN), 2014 reprint 2017).

Entre ombre et lumière, transparence et reflet, Brussels, Académie royale de Belgique (“L’Académie en poche”, 94), 2017.

philippe samyn

between light and shade, TRANSPARENCy and REFLEction

Académie royale de Belgique C oll ec tion L’Ac a dé m i e e n p o c h e-

Published in collaboration with

With support of

Académie royale de Belgique rue Ducale, 1 1 000 Brussels, Belgium www.academie-editions.be www.academieroyale.be

Fig. 38. MFP/Fig. 40. Matteo Piazza (MP)/Fig. 41. Guido Coolen/Fig. 42 and 43. ChB-JE/Fig. 44. F. Loze & Archipress Paris/Fig. 45. George De Kinder (GDK)/Fig. 46. ChB-JE/Fig. 48. MFP/ Fig. 49. AFM/Fig. 51. JMB + BEAI/ Fig. 52 and 53. MFP + BEAI/Fig. 57 and 58. +SVP/Fig. 59. J-L Laloux/Fig. 61.

AFM/Fig. 62. +SVP/Fig. 63. MFP/ Fig. 64. Daylight Liège/Fig. 65. ChB-JE/ Fig. 67. J. Bauters (JB)/Fig. 68 and 69.

MFP/Fig. 70. AFM/Fig. 71. MP/Fig. 72.

MFP/Fig. 73. JB/Fig. 77 ChR/Fig. 78 and 79 MFP/Fig. 82 GDK + M. Jaspers

Collection L’Académie en poche Under the academic responsibility of Véronique Dehant Volume 94-EN © 2017, Académie royale de Belgique Credits © Philippe Samyn, for the text Illustrations © Samyn and partners and the photographers (+ architects partners) for: Fig 1. +BEAI/Fig.10 and 11. Christian Richters (ChR)/Fig.12. +Studio Valle Progettazioni (SVP)/Fig.13. MarieFrançoise Plissart (MFP)/Fig. 17 and 18. Christine Bastin and Jaques Evrard (ChB-JE)/Fig. 19. Studio Claerhout/ Fig. 20. +SVP/Fig. 21 and 22. ChB-JE/ Fig. 23.MFP/Fig. 25. Centre Scientifique et technique de la construction Be/ Fig. 31. Andrès Fernandez Marcos (AFM)/Fig. 36. Jean-Michel BYL (JMB)/

Follow up: Loredana Buscemi, Académie royale de Belgique Cover: Model of the glass sculpture for the head office of AGC in Louvain-laNeuve ; p : 2010, r : 2011-2014 (01/577) Printing: IPM Printing SA, Ganshoren ISBN 978-2-8031-0602-8 Dépôt légal : 2017/0092/12

Introduction

The cover image 1 shows a section of a glass sculpture, which needs to be visualised in the empty space around it 2.

It encapsulates the subject of this small work.

Complex transparencies, shade and reflections originate from a form that is actually very simple in terms of its geometry, but this ephemeral sculpture only becomes real thanks to the 1

2

Photographs and photographed models are themselves either reflections of a proven or anticipated reality, or shadows of the memory of their failure to materialise, as is the case for the projects that illustrate this subject.

The white glass parallelepiped (with its transparency, shade and reflections) on a square base measuring 62 × 1.35 m = 83.7 m on each side and 4 × 1.8 m = 7.2 m in height (4 × 1.35 × 4/3), the head office of AGC Europe in Louvain-la-Neuve acquires its lightness, along with that of its bell tower: the ancillary parallelepiped to the extra-clear glass sculpture (with transparency, shade and reflections of another kind) of 10 × 1.35 m = 13.5 m long, 1.35 m deep and 10 × 1.8 m = 18 m (10 × 1.35 × 4/3) high. Its foundations are ready and awaiting its construction, which I hope will proceed in 2017 (01/577 — Fig. 1).

The 4/3 ratio (and the 1.35 m dimension) presages Pythagoras’ theorem on triangles (and the human scale).

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thoughtful use of concrete construction technology.

Large expanses of extra-clear toughened glass 3 (1.35 m × 1.35 m and 1.35 m 1.80 m rectangles − 12 mm thick) form the object’s motif.

They are encased in a cage of 12 mm × 12 mm section high-strength stainless steel bars 4, by means of neoprene blocks 5 at their four corners with silicone sealant joints 6. Use of the latter is questionable (as these are not yet recyclable) but there is still no substitute available that is able to guarantee structural stability that is verifiable by means of sophisticated calculation software.

Light and shade induce transparency and reflection. They lie at the core of my work and I am constantly exploring both their practical and theoretical aspects.

With historical benchmarks and figures as evidence, in this work, I engage in the perilous exercise of linking my projects to both theoretical and scientific concepts, abstract reflections of work that is among the most tangible, inspired by the patron’s grand vision and the genius loci (spirit of the place).

3

4 5

6

These materials are described below, in the body of the text.

Ibid.

Ibid.

Ibid.

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Introduction

Our senses and the paradox The use of all five senses is essential, MerleauPonty writes “…for my body to awaken the associated bodies. 7” It is by means of the five senses that architecture, an activity of the human body and mind, acquires its reality in the world.

However, the oculocentric culture of Plato (~428 to 348 B.C.) places us in a cave where shadow and reflection ignore the sense of touch, smell and taste, even where, in extremis, they conjure up the acoustic echo, as described in such an inspirational way by Victor Stoichita 8.

So, am I a prisoner of this cave? The answer is both positive and negative.

On the one hand, it must be admitted, without regret, that this work cannot aspire to cover the entire architectural field, but focuses solely on one aspect of the art of building, which has essentially developed to serve the senses of sight and hearing. There is no need to invoke, as if to apologise, a “dematerialisation” effect triggered by new “virtual reality” technologies, since the following thoughts themselves, put down on paper, can only be read with the 7

8

Maurice Merleau-Ponty, L’œil et l’esprit (Eye and Mind), preface by Claude Lefort, Paris, Gallimard, Folio essais, 1964, p. 13.

Victor I. Stoichita, Brève histoire de l’ombre (A short history of the shadow), Geneva, Librairie Droz, 2000.

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eyes. You will not touch or smell the aroma of materials, nor their intimate relationship with the taste of mouth-watering food, and I will only briefly allude to the sensory role of materials, which is equally as decisive for the enjoyment of architecture.

On the other hand, although it is limited, in this case, to visual and auditory perception, architectural design thinking should nevertheless be global in its nature.

In effect, architecture is built by acts of creativity, discovery and inventiveness, and enters the realm of art, science and engineering: —— like art, it draws “on this well of raw feeling,… in complete innocence 9”; —— like science, it “manipulates things, establishes internal models for itself and, on the basis of these indices or variables, making the transformations that their definition allows, only infrequently encounters the modern world 10”; —— like engineering (or technology) it shapes matter in the quest for invention, —— like philosophy, all architectural questions must be posed from the standpoint of perception and feed on the observation of paradoxes.

Among the latter, the most fundamental appears to be that articulated by Merleau-Ponty 9

10

Maurice Merleau-Ponty, op. cit., p. 9.

Ibid., p. VII. 10

Introduction

on the subject of painting and which can be applied directly to construction: “its endless questioning, which is repeated with every work, will not result in a solution and, yet, provides an understanding, with the unique property of only obtaining this understanding, of the visible, by means of an act that makes it come alive on a canvas. 11” This is the paradox of architecture, which is both an intractable question and answer.

11

Ibid., p. VII. 11

Ch a pteR 1

A knowledge base

Pliny the Elder’s (23 to 79 A.D.) myth of the origin of art, with the tracing of lines around a human shadow, and Plato’s myth of the origin of knowledge, with the projection of the shadows of reality on the wall of his cave/prison 1, still represent expressions of our original lack of imagination.

We can escape from this prison, once more, via the paths of artistic creation, scientific discovery and technical invention.

Construction lies at the crossroads of these three paths and that is where I stand, examining the light that enters through the transparent parts of constructions, and the accompanying shadows and reflections.

My countless questions are those of a builder who is preoccupied by the meaning of his actions and vexed by the concern of only seeing 1

Again, it is Stoichita who makes this fascinating comparison.

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the shadow of reality. Fortunately, my cave is filled with countless books, both theoretical and practical, which give me what I need to establish a knowledge base on which I can rely in my daily practice and which, in return, is constantly updated by its encounter with the latter. construction Over the course of several millennia, buildings have displayed consistent characteristics originating from the human soul and physiology, as well as the surrounding environment.

These constants, including shadow and reflection, form the subject of the theory of architecture and construction, including the oldest known theory to date, which still retains all its relevance, that of Vitruvius 2.

Françoise Choay 3 deals only with Vitruvian theory because of its coherence, enhanced by that developed by Christopher Alexander and his team in the 1970s 4 for architecture alone.

2 3

4

Marcus Vitrivius Pollio (known as Vitruvius ~ 90 to 20 B.C.), De architectura.

Françoise Choay, La Règle et le Modèle : sur la théorie de l’architecture et de l’urbanisme (The Rule and the Model: On the Theory of Architecture and Urbanism), Paris, Éditions du Seuil, 1980.

Christopher Alexander, Sara Ishikawa & Murray Silverstein, A Pattern Language, Oxford, Oxford University Press, 1977. See also The Nature of Order. An essay on the Art of Build14

A knowledge base

Firmly founded on this proven theoretical basis, my thoughts always originate from the “production” of an architect’s and engineer’s project. I must repeat that the source material for this is both the client’s grand vision and the analysis of the genius loci (spirit of the place) which produces a different result every time.

Hence, my thoughts are concocted from snippets and fragments, on several subjects at the same time; those originating from a given “production” process, interacting, as ever, with those originating from others. They are combining and complementing each other gradually over the years and during the course of my projects, and I occasionally attempt to summarise them 5.

5

ing and the Nature of the Universe (Book 1: The Phenomenum of Life. Book 2: The Process of Creating Life. Book 3: A Vision of a Living World. Book 4: The Luminous Ground), Center for Environmental Structure, Berkeley, California, 2002.

Bulletin de la Classe des Arts, Académie royale de Belgique, 6e série, t. VII, 1996, 1-6, p. 131-137: “La petite ville possible de trente mille habitants” (“The potential small town with thirty thousand inhabitants”); t. XI, 2000, 7-12, p. 251-263: “La terre étroite” (“The narrow planet”); t. VXII, 2006, 1-6, p. 45-53: “La ruine utile et la construction efficiente” (“Useful ruin and efficient construction”); “Étude de la morphologie des structures à l’aide des indicateurs de volume et de déplacement” (“A study of the morphology of structures with the help of volume and displacement indicators”), Mémoires de la Classe des Sciences, Brussels, 2004, 482 p*. The vertical city, Brussels, L’Académie en poche, 2014, 122 p.* ; as well as: Philippe Samyn and Pierre Loze, Devenir moderne ? Entretien sur l’art de construire (Becoming modern? An interview 15

between light and shade, TRANSPARENCy and reflection

Following a major transformation in the way of producing buildings from the 19th century onwards, modern construction is no longer entirely governed by the constants of Vitruvian theory. The discoveries and inventions that regularly appear thereby incrementally define a set of “constructional variables”, which the technical community strives to define, document and schedule: performances, materials in line with their form and nature, construction elements and even functional programmes 6.

Furthermore, in line with changes in society, these technological transformations generate an ever increasing body of legal and normative texts; these interact in various ways with the “constructional variables” originating from the building sector itself, to contain them, direct them or drive them. Given their legal value, they are of prime importance but are, most often,

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on the art of building), Brussels, Mardaga Editeur, 1999 ; or even Principes de construction à l’usage de mes étudiants et collaborateurs (Principles of construction for use by students and colleagues), April 1997* (* e-book from www.samynandpartners.com).

The SfB classification system, developed in Sweden (Samarbetskommittén för Byggnadsfragor), has been recommended by the International Council for Building Research, Studies and Documentation since 1959. It has been applied in England under the name Ci/SfB since 1968 and the Centre d’Information et de Documentation du Bâtiment published the French version — Si/SfB — in 1973. It is extremely efficient and allows data to be filed and processed on computer; for drawings, texts and figures.

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A knowledge base

drafted in haste and without taking a step back from events, they evolve in line with the latter far more quickly than the subject that they codify.

Nor can they keep pace with the speed of scientific and technical progress and thereby hinder its application, to the point that the time between an invention (or discovery) and its practical implementation is generally several decades in the construction industry, even though this period rarely exceeds a year in other industrial sectors.

The concept of sustainability may serve as a guide to finding one’s own way in this changing environment.

In effect, construction is static, it does not fly, sail or travel on land. Its form should always originate from the requirements it needs to satisfy. Thus, for example, although they are necessary for planes, boats and cars, the aerodynamic and fluid forms (chiefly without the trace of a shadow!) that we see everywhere nowadays, are entirely inappropriate for a building.

Therefore, the search for savings on materials and lightness is essential for construction, not to enable it to move better 7 but out of respect for the environment.

7

We must pursue intellectual exploration of static construction, just like Bertrand Piccard and André Borschberg are doing for mobile construction with the Solar Impulse plane!

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This is precisely the subject of my work on the morphology of structures.

As I examined in “La ruine utile et la construction efficiente”, the sustainability “P” of a structure is inversely proportional to its efficiency “E”: the product — “E” × “P” — is a constant — “C” — at a given place and time.

The drawing of a construction and its component parts, to limit waste and unnecessary work on site, is just as important 8 as the progress of science and technology is in increasing the value of “C”: this is “sustainable development” [Fig. 2]. the world of economics No thoughts on construction seeking to be relevant can be framed without reference to the economic system that prevails in our democratic society and whose aim is to establish peace. I am referring above to the slow speed at which the construction industry incorporates inventions and discoveries, but what are we to think of this system that has taken more than sixty years, since the work of Jay Wright Forrester 9, to acknowledge 8

9

Especially since the materials and constructive elements are industrialised. Although brickwork produces minimum waste, this is already no longer the case for timber frameworks!

Only a few years after inventing magnetic core memory, from 1956 onwards, Jay Wright Forrester developed the theory of “System Dynamics” and its application in industry (Industrial 18

A knowledge base

its interrelationship with the planet’s ecosystem. I should like to draw your attention, among many recent works, to the following books: The Third Industrial Revolution by Jeremy Rifkin 10 and Collapse by Jared Diamond 11. I mention the second of these because its anthropologist author’s analysis adds, if it were needed, even more weight to the arguments of the first, which serve as a backdrop for the following thoughts.

The economist Rifkin analyses the implosion of global society, which we all feel to varying degrees, based on the model originating from the second industrial revolution.

Nevertheless, he perceives the strong emergence of the third industrial revolution and defines its five pillars (renewable energy, low energy buildings and/or electrical energy-producing buildings, energy storage, electrical power distribution using smart grids following the example of communication distribution grids, electric cars or vehicles with fuel cells).

Dynamics, 1961, and Urban Dynamics, 1969, Cambridge, MIT Press; Principles of Systems, 1968, and World Dynamics, 1971, Cambridge, Wright-Allen Press). World Dynamics is one of the subjects of my studies at MIT in 1971-1972 and is equally as decisive as the refined structural calculation theories in the composition of my intellectual roadmap.

10 Jeremy Rifkin, The Third Industrial Revolution, New York, Palgrave Macmillan, 2011.

11 Jared Diamond, Collapse : How Societies Choose to Fail or Succeed, New York, Viking Press, 2005.

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He derives from this an empathetic society living with respect for the biosphere, which attracts and delights me. However, I will only make reference here to his thoughts on the energy aspect as it relates to construction: 1. The second fundamental law of thermodynamics relating to entropy states that all energy deteriorates, from available to unavailable. It goes from hot to cold, from concentrated to dispersed, from order to disorder.

I would add that all buildings, even the most energy-efficient, consume the energy needed for their own construction, as their aim is to meet human needs, i.e. to move from cold to hot, from dispersed to concentrated and from disorder to order.

2. Renewable energies are becoming available to everyone, everywhere: e.g. solar, wind, hydroelectric, geothermal and biomass energy 12. Their deployment removes the need for a pyramid-style economic power structure, as engendered by the previous concentration of energy production, and requires society to be organised as a network. Our new buildings (like our vehicles) are all becoming small production and storage units 13.

12

The mastery, far-off perhaps, of nuclear fusion cannot be ruled out.

13 This is all the more desirable, or inevitable, given that the cost of top-down (pyramid-shaped) distribution of any kind is 20

A knowledge base

3. The networking of communication and energy is resulting in the disappearance of numerous very large industries with their commercial intermediaries, and strengthening the direct link between citizens and creators, inventors and discoverers. The latter are making their achievements available without selling them: resulting in a renaissance of the greatest expressions of art and craftsmanship with a major impact in terms of architecture and civil engineering.

So, this is a summary of Rifkin’s thoughts relating directly to the act of building. energy and society Our lives are punctuated and defined not only by our relationships with others, but also by the daily and seasonal cycles of nature. Each day influences our experience, in a different way, depending on the season, latitude and nature of where we are, variations in temperature, humidity, the colour and intensity of light, its direct or diffuse nature, sounds, odours and the conditions of surfaces that we touch. The purpose of a shelter (construction) is to limit, or even eliminate, the adverse effects of nature on our lives without depriving us of its benefits. This is what is so charming about old or increasing far more rapidly than the population served (see The vertical city, note 17).

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rudimentary buildings, in harmony with nature, towards which we are irresistibly drawn when we are looking to relax and unwind and, perhaps, to remember our childhood huts. In cities, pets allow many people to make up for the lack of this primordial connection.

Nothing, in theory, should deprive a person of the enjoyment of their senses and yet few of the last century’s buildings (including mine), even those forming part of the “modernist” movement admired by architects themselves, avoid this pitfall. Worse still, the gradual reduction in their sensory and emotional “performances” has gone hand in hand with an increase in their energy footprint, both in terms of their construction as well as their operation and maintenance. What is more, they can no longer be dismantled, which further increases their environmental burden for future generations.

The only repercussions of the warning in the MIT report to the Club of Rome in 1972 14 and the first oil crisis in 1973 in the world of construction are the slow and gradual establishment of standards and regulations, which are as nume14

Under the leadership of Dennis L. Meadows (and influenced by the work of J.W. Forrester), the report The limits to growth highlighted the five main problems for mankind: the acceleration in industrialisation, strong growth in the world population, the persistence of worldwide malnutrition, the depletion of natural non-renewable resources and environmental degradation.

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A knowledge base

rous as they are inefficient for as long as they do not call into question our society’s philosophical attitude: all form and little substance. In architecture, formal and stylistic waves follow each other, but are only half measures: they are all naively cynical, including post-modernism, the “High Tech” movement or the numerous avatars of deconstructivism.

The current craze, in Europe, for so-called “passive” buildings is merely an expression of the latest stylistic wave, to the extent that it is constrained by legislation and normative documents, notwithstanding the fact that better insulation for a building (both its glazed areas and its opaque areas) and making it as airtight as possible makes complete sense, on condition that it is able to breathe. Therefore, from now on within the European Union, envisaging only erecting new buildings that produce energy that is surplus to their own requirements (which there is also the intention to limit), as called for by Rifkin, is of critical importance, as long as powerful energy companies are immediately required to transport this new widespread production using coordinated smart grids under the watchful eye of the European authorities.

Also provided that, and this lies at the heart of my argument, this new type of construction once again permits the unrestricted use of our senses and use of the most dismantlable and recyclable 23

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components possible. Finally, provided that a “constructive solidarity” is invented.

Based on the example of “social security” where the wealthy share their resources with those in need, “energy security” shares the energy saved or produced by new buildings with that consumed by old buildings, which are kept as they are as part of our cultural or social heritage. These new constructions can also benefit from the fertile contribution of high-tech craftsmanship and of artists, who are existential players in civil society.

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Ch a pteR 2

Light, transparency and reflection 1

I would now like to invite you to accompany me to a place where the materials (transparent, diffusing or reflective / rigid or flexible / watertight or permeable) and the elements of a building (structure, single or multiple envelopes, screen, etc.) interact, in their environment, with light and shade, transparency and reflection. This is illustrated by some of my designs and accomplishments 2.

1

2

The physical quantities in terms of light are: a. the light power of a source (expressed in Lumens: Lm), b. luminous intensity (in Candela: Cd), c. illuminance (in Lux: Lx), d. luminance (in Cd/m²), e. colour temperature Tc (in °K ), f. luminous efficacy (in Lm/W).

The reference (01/xxx) given for each of these enables the reader to obtain more details from www.samynandpartners.com. The illustrations (where p represents the date of the project and c that of its construction) relate to Belgium, unless stipulated otherwise. They are credited at the end of this work.

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daylight The light we are dealing with here, in this thin atmospheric layer measuring barely 120 km thick around the earth, has nothing to do with that beyond in the universe, which we only discovered a few decades ago thanks to the Hubble Space Telescope.

The term “daylight” covers a vast number of different realities. The intensity and colour temperature of this light vary according to the latitude, day of the year and time of day. It provides direct or diffuse light depending on orientation, cloud cover and the level of humidity in the air.

Its perceptible result depends, firstly, on the natural environment and, secondly, on that created by man.

At the same latitude and at the same relative time, the crystal-clear light of Marrakech in Morocco differs vastly from that which illuminates the mists of Kagoshima in southern Japan.

An urban atmosphere also differs from a rural atmosphere.

The colour temperature of “natural” light varies between 2500° Kelvin at sunrise and sunset to more than 5800° K at midday, and is modified when reflected by a coloured surface. The coloured surfaces of the outdoor environment, which is exposed to direct sunlight, thereby dictate the colour of the diffused light. Light determines the 26

Light, transparency and reflection

limits of perceptible colours, which vary from one individual to another. Architecture can play a part in this but without the natural reference point being lost, otherwise our condition could be distorted.

I produced this light chart with clear skies in Uccle, Belgium, for each hour and day of the year on a vertical surface 3 as well as on a horizontal surface 4.

The resulting two “Lux butterflies” [Fig. 3 and 4] are instructive and an opportunity for reflection and contemplation. They guide my thoughts from the first sketch for any project. orientation And latitude At a given latitude, the sizes and proportions of openings depend on their orientation and that of walls, facades and roofs, as well as environmental barriers to the sun’s rays. On this subject, it is essential to remember that the situation differs 3 4

Facing North, North-East, East, South-East, South, SouthWest, West, North-West.

It is to Robert Dogniaux that we owe the systematic measurement of these values, since 1954. Institut royal météorologique de Belgique, Publications série B, nº 12, Ensoleillement et orientation en Belgique. V. Etude de l’éclairement lumineux naturel (Sunlight and orientation in Belgium. V. Study of natural light illuminance), by R. Dogniaux, 1954. I have tried, thus far in vain, to obtain these measurements for other latitudes.

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greatly between the tropics, the tropics and the polar circles and beyond the polar circles.

While everywhere else on the planet the sun rises in the East and sets in the West, the area between the tropics sees the sun swinging from North to South at midday, depending on the season. From the tropics to the polar circles, at midday the Northern hemisphere sees the sun only to the South and the Southern hemisphere sees it only to the North. This is a crucial insight for architecture. In effect, the East and the West, which are stable throughout the entire year, represent the reference point between the tropics, while the North-South axis is the usual baseline beyond that. openings It is via openings, the holes in the wall or roof, that light enters buildings, directly, by reflection or in a diffuse way, and differently depending on their orientation, the season and the time of day, with their features, (windows or skylights, glazing, parapets, balconies, blinds, shutters, curtains). They determine the architecture 5.

All these components have changed considerably in recent decades but none of them has had 5

Read: La lumière naturelle à bon escient (Natural light used well), Ravel Office fédéral (Switzerland) des questions conjoncturelles, 73 p, 1995, available to download from the internet.

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Light, transparency and reflection

such a significant impact on the materiality of the envelope (facade or skylight) as glazing and sun protection.

Many other factors relating to openings have an influence on architecture including the question of the penetration of light into a room 6, which is always more efficient through the higher section. Consequently, the lower section of a window could be solid and better insulated, but this would deprive occupants of the pleasure of the view looking down, onto nature, community life and the interplay of shadows. This is why I prefer floor to ceiling openings, despite their reduced luminous efficacy, with windows equipped with a transparent parapet.

There is also the issue, among many others, of natural ventilation, which also raises questions of comfort, both acoustic and olfactory, and dust.

All these factors and questions interact when designing openings.

As for economic aspects, notwithstanding what is technically possible, there is a reason behind the size and proportions of openings.

6

The flexibility of use of this kind of room is also greater since it is high-ceilinged and shallow. A shallow building (12 to 13m) with ceiling heights of 3m is suitable for most uses (housing, schools, hospitals, shops, administration, workshops, etc.) and is therefore able to respond to changing needs. Conversely, the majority of deep buildings, in some cases built less than 30 years ago, cannot be adapted to meet changing needs and are destined for demolition.

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This means that an opening window should not exceed an area of one or two square metres, or have an excessive height in relation to its width, in order to be usable in practice.

GLazing Glazing must be as crystal-clear as possible, to guarantee the same colour perception as if it were not there or to “show colour” and become an artistic contribution — to be seen and not for transmitting light in order to see something else.

It is also through glazing that energy exchanges with the outside world are the greatest, which requires it to have the best performances in this field. It is also glazing that is currently one of the best media for photovoltaic cells and enables facades 7 to be designed as energy generators. Therefore, one of the tasks for the coming years consists of reconciling respect for the senses (good colour rendering, natural ventilation, etc.) with restrictions on energy losses, sun protection and energy generation.

Insulation of the envelope is specifically making a significant contribution to energy performances, with the major temptation being to reduce the glazed area or to increase its insulating performance, even if this means reducing 7

Chiefly their opaque sections.

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overall light transmission. However, this kind of reduction goes hand in hand with an increase in the time for which artificial lighting is used 8.

Counterintuitively, careful calculation of the optimum energy trade-off between the dimensions of glazing, insulating performance and light transmission, often results in large areas of glazing.

Although large panes of glass were being produced as early as 1665 by the “Manufacture royale de glaces”, founded by Colbert, for Louis XIV, their high cost means that their use was reserved for “special” buildings 9.

By contrast, ordinary window glass, produced from the middle of the 19th century until 1920 from blown and cut cylinders, was only available in limited size sheets. In 1925, Gropius again worked with this traditional limit for the large sectioned glazed openings of the Bauhaus in Dessau, while awaiting the worldwide commercial distribution of large panes of drawn glass.

When it arrived, this product allowed for the widespread use of very large windows and glazing, which, just like reinforced concrete and 8

9

It must also be sufficiently evenly distributed, which involves a large window and ceiling height as well as the building’s depth being limited.

Francis Poty and Jean-Louis Delaet specified sizes of 2.5 m × 1.7 m in 1806 and 8.14 m × 4.2 m in 1889, in their work Charleroi, pays verrier (Charleroi, the glassmaking city) edited by Centrale Générale à Charleroi, in 1986.

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narrow steel window frames, characterises the modernist movement.

Drawn crystal clear glass was produced on an industrial scale from 1903 10. Drawing leaves raised lines on the glass, which was unobtrusive but characteristic. This physical property of transparency and the resulting faint reflections represented both strengths and weaknesses. It could be polished to produce perfectly flat panes and used for double glazing (from 1912 in the United States), but was gradually superseded by so-called “float” glass 11 from 1952 onwards.

Manufacture of the latter uses less energy and allows very large panes to be produced. Some glassmakers, such as AGC Interpane in Germany, are now able to produce panes of glass measuring 3 m wide, 18 m long and 20 mm thick! However, the first generation of float glass had an emerald green tint, which was more pronounced the thicker it was, reducing light transmission 12 and, imperceptibly but genuinely, impairing colour perception 13. What is more, this glass could be 10

Drawn glass was invented in Charleroi by the Belgian engineer Emile Fourcault, with the French-Belgian Emile Gobbe, who filed his first patent in 1901.

11 Float glass was invented by the English engineer Sir Alastair Pilkington, who filed his first patent in 1952.

12 Glazing is also characterised by its light transmission (LT). This means that 6 mm to 12 mm thick extra-clear float glass has an LT of 91% compared to an LT of 87% − 88% for ordinary float glass.

13 Colour perception is measured by the color rendering index (CRI), a figure between 1 and 100, which represents the degree 32

Light, transparency and reflection

produced only with perfect flatness without the “materiality” provided by drawn glass, which is able to reveal its presence under light, requiring it to be “marked” where there is a risk of bumping into it.

The improvements made to float glass, designed to curb excess energy consumption and the discomfort resulting from the fashion for extensively glazed curtain walls, increased this impairing effect. The quest to reduce the total amount of energy that glazing allows to pass, in terms of incident solar energy 14, resulted in tinted heat absorbing glass and reflective glass with “vacuum” or “pyrolytic” coatings 15, in all colours to suit the architect’s wishes.

of concordance between the coloured appearance of an object illuminated by a given light source (or naturally through glazing) and the appearance of this same object illuminated by a reference source with the same colour temperature (or naturally).

14 The solar factor (S.F. or “g”, which is expressed as a %) defines the relationship between energy passing through the glazing and incident solar energy. g = 84% (and LT = 88%) for 6 mm ordinary single glazing , g = 74% (and LT = 79%) for 2 × 6mm ordinary double glazing, and can fall to g = 16% (LT ≤ 20% !) for coated glass.

15 The development of glass with thin coatings began in the 1960s.

Vacuum coatings are applied by cathodic arc deposition aided by a magnetic field. This is a nanotechnology, which does not yet have its own name (as it has been referred to since the 1990s) as these coats are between 10 and 800nm thick (nm = nanometre = 10 -9 m = 10-6 mm = 10-3 µm).

33

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The glass industry is now also encouraged to develop high energy performance products that are less reflective, thereby impairing colour perception as little as possible. For my part, I have been asking the glassmaking industry to include crystallized glass in its standard product ranges since 1990.

My awareness of the drawbacks of the lack of crystallinity in terms of glazing dates back to the project for the headquarters of the CNP/NPM (Compagnie Nationale à Portefeuille / Nationale Portefeuillemaatschappij), in 1994 [01/320, Fig. 5]. Albert Frère was looking for a facade in French stone, while I had been opposed to the use of thin stapled stone facade claddings for a long time 16. I, therefore, needed to find an answer that could reconcile my client’s wishes with my own concerns for construction orthodoxy. This is when I had the idea of using crystal clear glass, enamelled in a “French stone” shade on the inside and acid-etched on the outside. The result exceeded all my expectations as it does not just conjure up French stone, without any possible hesitation, but also has a visual depth that is completely new. Finally, the unattractive appea16

Stone slabs withstand the test of time, even when cracked, when they are set in a full mortar bed on a wall. They “live” on borrowed time when they are stapled at a few points and cover facade insulation panels. Thermal shock, for certain, and occasionally mechanical impacts, end up cracking the slabs before they fall off.

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rance of the stone when wet, resulting from its porosity, disappeared thanks to the water-tightness of the glass. Albert Frère was convinced. All I needed to do was find the required quantity of glass! At the time, this crystal clear glass was produced only at the end of life of the refractory cladding that lines the interiors of furnaces; it is rare and, therefore, highly sought-after. Fortunately, I was able to secure the necessary supplies by picking up the stock intended for maintenance of the grande bibliothèque de France, in Paris. This was not quite enough and some quantities from another source needed to be used, which a close observer would notice. The same glass is used for the windows, in an attempt, without a great deal of success, to mitigate the unpleasant effects of energy coatings 17.

Compelled by demand, all the major glassmakers set about producing almost “crystal-clear” float glass 18, which is also of benefit to the solar panel industry. Therefore, we now once more have crystal-clear glass that respects the colour of natural light, to the extent that thin coatings have not been applied to the double-glazed panes.

17

What is more, once fitted with effective double-glazed panes, at the time, the building was exemplary in terms of energy efficiency. Nevertheless, it is possible, twenty two years later, to improve its performance in an attempt to come close to zero consumption.

18 “Clearvision” from AGC (the most crystal-clear), “Ultra Clear” from Guardian and “Cristal” from Saint Gobain.

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However, this more transparent glass should reflect ultraviolet light (invisible to the human eye) in order to be visible to birds 19. two technological developments In my opinion, in future, two other major events relating to glass are likely to have a decisive influence within architecture.

The first relates to vacuum double glazing, invented in 1989 at the University of Sydney by Richard E. Collins and Steven Robinson, and produced on an industrial scale in Japan by NSG (Nippon Sheet Glass) since January 1997 20 under the “Spacia” brand. This product is revolutionary, but it has taken all the time since then for its “evidence” to emerge and for it to very soon be available in Europe (with other characteristics and improved performances).

19

Katarine Logans in her article “For the birds” (Architectural Record, 10/2015, pp. 148-154) notes that “hundreds of millions of birds” die each year as the result of hitting glass panes in the United States of America alone! Yet glazing with “UV” coatings is not available in Europe. An internal memo from AGC (David.Kelich@eu.agc.com) without a reference or date, refers to only “one hundred million birds in Europe” (received by e-mail on 2015.12.17 / 18:04, Bhadresh Parbhoo@eu.agc.com).

20 ECBS News, Issue 27, June 1998, pp. 7-10 : “Vacuum Glazing Research Program at the University of Sydney, Australia”. NSG sent me samples to the office dating from as far back as 199811-04!

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This initial double glazing comprises two panes of 3-mm-thick float glass set 0.3 mm apart, between which there is a vacuum. Small stainless steel cylindrical columns with a diameter of 0.5 mm, positioned every 20 mm in both directions, prevent the panes being drawn together by the vacuum. Traditional double glazing edge dividers, generally made from synthetic sealant and a rigid profile (aluminium, steel, etc.) forming a 20 − 25 mm opaque black edge, reduce the glazing’s energy performances the smaller the latter is (what is commonly known as the edge effect). Moreover, it is not recyclable 21. In this case it is replaced by a ceramic sinter, which is less than 6 mm wide, reducing the edge effect to the bare minimum.

By stretching the argument, the system has a number of virtues. In the currently anticipated versions, its level of thermal insulation is far superior to what can be achieved with the best energy performance triple glazing known to date. The new vacuum glazing produced in Europe should therefore have a heat transfer coefficient of U=0.3 W/m2 °K 22, in both a vertical 21

While the terms “circular economy” and “cradle to cradle” are on everyone’s lips, no-one is concerned about the “mountains” of aluminium slats, sealants and fragments of glass that are piling up in the waste tips of our ports.

22 The heat transmission coefficient U (in W/m² °K) of 6 mm single glazing is 5.7; that of basic double glazing varies between 2.7 and 3.3; that of the best current insulating glass is 1.0 to 1.2 37

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and horizontal position 23. It is very easily recyclable, being primarily made of just silica and small stainless steel columns. Its thickness is virtually that of single glazing and its edge is so thin that it is able to replace small glazed panes in the thin wooden frames of all, what are known as, heritage buildings. Although they are crystal-clear, the discrete presence of small blocks of stainless steel revives the “presence” of drawn glass in these panes. However, the size of the glazing currently produced using this process is restricted to 1.5 m by 3 m, but larger formats are expected with glazing that is more than 6 mm thick.

The second event relates to the sharp fall in the cost of silicon photovoltaic cells (switching from an edge of 10.4 cm to 15.6 cm (from 4 to 6 inches): from 3.3 USD/PW in 2006 to 0.60 USD/ PW in 2012 and to 0.38 USD/PW in April 2016 24. and falls to 0.7 for triple glazing. 1997 Spacia glazing has a U value = 1.4 W/m² °K. 23 This is an additional property, as current double or triple glazing sees its heat transfer increase significantly as it moves away from the vertical. For example, the U value of high insulation double glazing changes from 1.1 in a vertical position to 1.7 in a horizontal position, which represents a reduction in heat resistance of more than 50%.

24 Laurent Quittre, ISSOL, e-mails to Samyn and Partners 2012.05.23/16 :03 and 2016.03.10/16 :27 (this is the US dollar per Peak Watt (PW), based on the Bloomberg index) and average prices, for both mono- or poly-crystalline cells.

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In the meantime, the data relating to the harvesting of solar energy, at all points on the planet and whatever the orientation, has also become available to download, for example from the website of the Joint Research Centre (European) in Ispra, Italy 25.

It enables polar charts to be produced, like the two that I prepared for the Issol project in the “Les Plénesses” zoning in Verviers, Belgium [01/592, latitude 51°N, Fig. 6 and 7] and that for the reception centre for the cultural village of Lujiazhi in Zhoushan, China [01/574, GM 26, latitude 30°N, Fig. 8 and 9]. It also shows the path of the sun. It specifically shows that the annual energy, in kWh/m², harvested on a North facing vertical face, is still 35% of the South facing optimum for Belgium and 20% for Zhoushan.

Thus far, we have endeavoured to use these cells sparingly by generally aligning them, as recommended by traditional best practice, perpendicular to the azimuth position of the sun on 21st June. Today, the sharp fall in the cost of cells and the availability of sunshine statistics have completely overturned this paradigm. Cell 25

26

E-mail: jrc-info@ec.europa.eu This is the point, at the end of 2009, when I began to work with Georges Meurant, whose compositions of coloured rectangles have since appeared in a large number of projects (indicated by the initials “G.M.” after the file no.). Regrettably, this first project in Zhoushan was marred, since it was not possible to manage the implementation plans, or the construction site.

39

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surfaces with an orientation that is not ideal are becoming economically profitable.

Therefore, a building that produces energy, thanks to its envelope, at an affordable cost is within reach, as long as its supporting structure does not excessively affect the cost, and this is far from being a question of detail, and the power grid actually becomes “smart” and accessible to everyone.

What we need is to develop an architecture that incorporates these cells in a “friendly” way.

Photovoltaics are not a panacea and it is essential to evaluate the most appropriate source of renewable energy, based on the particular site.

In 1998, the use of photovoltaic cells on the facade of Hendrik Seghers’ castle, which I will cover below, or for Houten Fire Station [01/373, Fig. 10 and 11], was of an experimental, or almost symbolic, nature. The same was not true in 2006.

This was the point at which the Council of the European Union became convinced of the relevance of covering its new headquarters, the EUROPA building, with a photovoltaic “sunshade” [01/494, GM, Fig. 12] and that the envelope of the Euro Space Centre at Libin-Transinne (facades and roof) [01/518, Fig. 13] was designed as a genuine power plant with an installed capacity of 439 kWp (and annual production on the order of 370 MWh, i.e. 91% of the centre’s 40

Light, transparency and reflection

electricity requirements). In these two cases, the panels are still optimally oriented.

I am currently proposing a continuous envelope of photovoltaic panels for all the opaque sections of the external facades of the new building for the Faculty of Applied Sciences at the Free University of Brussels, on boulevard du Triomphe in Ixelles.

This outward adornment, still in bluishblack, contrasts with the white walls of interior patios, intended to reflect natural light [01/570, Fig. 14 and 15].

These panels provide an output of 180 Wp/m² 27 which would have only been 100 Wp/m² barely 10 years ago.

Moreover, emerging technology based on organic components (“OPV” organic photovoltaic) could herald the arrival of transparent panels.

Laminated and toughened glass The impact resistance of fragile sheets of glass is increased when they are made from one or more layers bound together by one or more PVB (or 27

The output of the cell alone is currently 210 Wp/m², and 280 Wp/m² for space applications. As it is hard to imagine a city where the buildings are all black, (almost) white photovoltaic panels with an output of 90 Wp/m² are now emerging.

41

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EVA) 0.38 mm transparent films 28. This glazing also has the advantage of blocking ultraviolet radiation.

The combination of sheets of toughened glass 29 and ordinary float glass improves the 28

Laminated glass was invented in 1903 by the French chemist Edouard Bénédïctus (1879-1930) and was patented by him under the name Triplex. Nevertheless, it was the invention, in 1927, of PVB (polyvinyl butyral) by the Canadian chemists Howard W. Matheson and Frederick W. Skirrow that marked the starting point for the use of laminated glass for car windscreens, from 1936 onwards in England. We had to wait until the 1960s for its application in construction, 1980 for the first Belgian “standard” (an STS — spécifications techniques unifiées (unified technical specifications)), and 1989 for Belgian standard NBN 23-002.

EVA: ethylene-vinyl acetate was developed in 1950 and marketed by ICI (Imperial Chemical Industries).

29 A pane of toughened glass, patented in around 1930 by Rudolph Seiden (1900-1965), is approximately two to five times stronger than an ordinary pane of glass as it is pre-stressed by slow heating followed by rapid cooling of its external surfaces, which are compressed by the contraction and tension exerted by cooling on the centre of the sheet. “Reinforced” (wire) glass invented by Frank Shuman (1862-1918) in 1892 and made up of a fine mesh of steel wires moulded into the glass, was the first attempt to provide glass offering a degree of safety. However, as the steel’s thermal expansion coefficient is twice that of drawn glass and three times that of borosilicate glass, it is doomed to fail when subject to repeated temperature variations. This makes it all the more surprising that it was still being used for the leaves of fire doors in the United Kingdom until recently. In addition to their low mechanical strength, and like the majority of polymers, PVB and EVA are subject to creep, which does not enable the properties of glass to be fully exploited. This is why I suggested to AGC, in 2010, that it was necessary to develop a new type of reinforced glass (owing to the significant recent 42

Light, transparency and reflection

safety of this laminated product, as the first layer shattering into small fragments is counteracted by the second breaking into pieces. As a result, it can be used for parapets 30 and glass floor elements. The use of this glass has been mandatory for all overhanging glazing, such as canopies, since 2014 and now also for large vertical panes in public spaces and in areas at risk from tornadoes and typhoons.

However, its poor mechanical performance in relation to its cost means that it is often used only sparingly, for one “high point” or other in the construction. This is exactly how I used it for the small glass roof cupola, providing a view of the polished stainless steel weather vane designed

by Olivier Strebelle, on a small wooden building in Waterloo 31. In common with the mirrors that I talk about below, this weather vane reflects the sun’s rays into the meeting room on the second progress in terms of adhesives) using a fine mesh net of paraaramid filaments, the strength of which is equal to that of the best steels but whose thermal coefficient is that of ordinary glass, or even borosilicate glass, which would eliminate the faults of steel reinforced glass.

30 For me, I prefer using perforated sheet as described below.

31 I discovered at his home, in around 1985, models of monumental sculptures that he was not able to produce for Sart-Tilman and benefited from this small weather vane to test the device on a smaller scale before asking him to produce the three large ones that stand atop the mound that I created at Shell’s Chemical Research Centre (CRCSL) in Louvain-la-Neuve; p: 1986, c: 1987-1988 — (01/160).

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floor, as the wind blows, and then, by means of a round pane of laminated glass in the centre of its table, towards the entrance hall [01/200, Fig. 16, 17 and 18].

Mirrors reflecting natural light I have been fascinated by mirrors for a long time.

I use them specifically to reflect natural light, as in the deep reveals of the narrow windows of the Ferme de Stassart in Uccle, which I began restoring in 1991 to house my team of architects and engineers [01/265, Fig. 19]. It not only enables the amount of natural light to be increased but also provides a very pleasant sideways view of the outside world.

Since then, I have used this arrangement frequently when restoring or renovating old buildings, as in the window reveals in “Block A” of the Résidence Palace incorporated into the Europa building [Fig. 20].

I subsequently decided to examine the use of reflective surfaces or mirrors placed “as a visor” between the viewing section and the glazed upper panel of a window, with the aim of illuminating the ceiling and, at the same time, providing shade (what are commonly known as “light shelves”).

This is the reason why, in 1992, when developing an office building, standing at the junction of 44

Light, transparency and reflection

Avenue Michel-Ange and Avenue de Cortenberg in Brussels [01/260, Fig. 21 and 22], I realised that an external aluminium grating would be able to perform this role relatively efficiently, with the advantage of never needing to be cleaned.

The result is so convincing that, when visiting the building in 2000, Jan Pieter and Dirk de Nul effectively adopted the same system for their first new headquarters in Aalst [01/401, Fig. 23].

In 1997, I also designed anidolic reflectors 32 for the Caisse Congés du Bâtiment project in Brussels [01/351, Fig. 24 and 25]. Placed on the outside, their cylindrical form makes them the most powerful reflectors 33. They also highlight the rhythm of the facade elements in relation to that of neighbouring buildings. The efficiency of the system, viewed with scepticism at the time, appears to me to be worth reconsidering, despite the resulting cleaning costs.

When playing absent-mindedly with a mirror in early 1999, I realised that there was a possibility of reflecting diffuse light, modestly but effectively. This inspired me to propose new facades for a building at the Rond-Point Schumann in 32

An anidolic reflector is a light shelf that uses curved specular reflectors designed to reflect a greater proportion of the diffuse light from the sky than a flat mirror would do. The concept has been studied since 1993 by Raphaël Compagnon at the EPFL (Ecole Polytechnique Fédérale in Lausanne).

33 This study was conducted at the BBRI (Belgian Building Research Institute), by Ir Peter Wouters.

45

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Brussels, where large panes of glass with a semireflective pyrolitic coating reflect light coming from the North into the offices, without obstructing the view [01/381, Fig. 26].

Ultimately, even ordinary glass always reflects something 34. natural light sensors Other recent technological developments are paving the way for new ways of transporting natural light, with or without concentrating it. This is the reason why we now have sensors made from shells, in the form of segments of paraboloids of revolution, with an axis that always points towards the sun, concentrating the sun’s energy on a single point (the focal point of the parabola). At this point, the visible fraction of the energy is transferred via a fibre optic bundle 34

Apart from glass with an “anti-reflective” coating. The decline in reflection from old panes of glass was observed for the first time by John W. Rayleigh, in 1887. The first anti-reflective coating, which was unreliable, was discovered by Harold D. Taylor in 1896, and patented in 1904, again in England. It was not until 1935 that Aleksander Smakula at Carl Zeiss patented the first reliable process, and until 1990 for 99.5% transmission to be achieved.

The most effective current anti-reflection coating is produced

by Schott with the brand name “Amiran”. It has a visual reflection level of 1% for single glazing and 2% for double glazing, compared to 8% and 15% respectively for “untreated” glazing.

This level rises to 20% for triple glazing!

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and the calorific infrared radiation is converted into electrical energy. The fibre bundle can then be divided, like the human vascular system, to power point light sources.

Although these devices are still unaffordable for common application 35, the International Polar Foundation allowed me to include them, in 2004, for its “Environment Centre” project in the grounds of Toronto University [01/477, Fig. 27, 28 and 29].

With a completely solid wood structure, 24 tubular columns 36 support the floors and include a fibre optic core powered, during the day, by light — top-down — from these sensors placed on the roof and, during the night — bottomup — by powerful mercury vapour and metal halide lights (themselves powered by batteries charged during the day by the sensors). These major arteries then distribute light through the 35

The subject is only just starting to arouse the interest of industry, and still only very tentatively. Various new companies are working on it, including Echy, founded in France in 2010 by Quentin Martin-Laval (X-Pont 2012) and Florent Longa (X 2012) while they were still studying at the Ecole Polytechnique, which is already offering small cost-effective systems.

36 I intended creating these columns using unwound sheets of wood (veneers), re-rolled like a Havana cigar. This process was invented on 24th November 1995 by Karel Kunnen as part of practical work for a course on wooden structures that I held for future civil engineers at the Free University of Brussels.

It enables uniform solid or annular, cylindrical or conical, wooden columns to be created. I have not built any of these as yet but I still view this idea as extremely promising.

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networks of veins, followed by horizontal veinlets, to power the lighting.

As for these sensors, it is also possible to place ordinary mirrors on heliostats such that they follow the sun’s trajectory and reflect the rays as a beam of light in a constant direction.

This beam can then be reflected by one or more mirrors, also stationery, to illuminate any area of a building. It was these heliostats 37 that I proposed in 2010 for the House of European History project in the former Eastman Building in Parc Léopold, Brussels [01/573, GM, Fig. 30]. A set of mirrors, whose reflective surface is always facing downward and is therefore sheltered from vertical rain, reflects the sun’s rays vertically into a light shaft, where they are diverted horizontally, to enter the exhibition rooms. There, they are finally reflected in converging, parallel or divergent beams, to illuminate the objects exhibited. The dark walls of the rooms are pierced by black-walled cylindrical tubes that are long enough (1m for a diameter of 20 cm) to prevent transmission of the diffuse light originating from the light shaft itself [Fig. 31].

37

I proposed them for the first time in 1996 for the reception centre, below the North face of the Erasmus Hospital in Anderlecht, in order to “soak up the sun” (01/336) and, then, in 2000 to light the stage of the Aula Magna in Louvain-la-Neuve (01/291).

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Without further success, in 2010, I proposed a heliostat with an elliptical mirror to illuminate the coffin in each ceremony room of the crematorium in Aalst [01/583, Fig. 32, 33 and 34] and in 2014, 232 of these to illuminate the heart of the Guggenheim Museum in Helsinki [01/619, Fig. 35 and 36].

It was ultimately only in 2016 that I finally succeeded in creating one at the Fire Station in Charleroi, to channel light from the roof into the public underground car park [01/569, Fig. 37].

Water as a mirror Bodies of water and rivers provide the most fascinating natural mirrors and the most extraordinary light shelves (their thermal mass also tempers the atmosphere).

They carry dreams 38 and draw light from the earth to illuminate their banks and the buildings that surround them, as in the courtyard of the Ferme de Stassart 39 which houses my team [01/265, Fig. 38] or the patios at the Fire Station in Charleroi [01/569, Fig. 39].

38

As a child, my gaze would wander to the broad meander of the Lys as it reflected the clouds, to the North of my family’s garden in Afsnee-Gent.

39 The pond also reflects the clouds and the oak tree, which is the same age as my team and my oldest daughter Virginie.

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Similarly, the research centres for M & G Ricerche in Venafro, Italy [01/222, Fig. 40] and OCAS 40 in Zelzate [01/223, Fig. 41], are reflected in the pools that surround them (in the case of the former, they also play a vital role in providing air-conditioning beneath the tent).

A double skin The numerous functions that the envelope of a building needs to perform result in it having a “thickness” that combines the respective efficiencies of the constructive elements.

The thick masonry wall addresses these needs with numerous features: alcoves, balconies, shutters, loggias, curtains or drapes in its windows; bands, projecting sills, low reliefs, canopies and eaves on its solid sections.

They protect and shape the facade, giving it a human scale and visual depth, aided by the interplay of shadows and reflections.

I adopt the same approach for large areas of transparent glass (ultra-clear, as it should be).

These “open” facades draw the eye inside and, at first, into the protective depth of the building’s envelope, an empty space populated by construc40

Onderzoek Centrum voor de Aanwending van Staal, on the Sidmar site.

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tive elements, as with the features of openings and solid sections of the masonry wall.

This empty space may be external (in a temperate environment) or enclosed by a second transparent envelope protecting the first (a “double skin”) where, for whatever reason, the first envelope alone is not able to guarantee one of the desired performances, whether this relates to safety or protection from the cold, heat, rain, wind, dust or noise, or even where the buffer space between two glazed areas is used for convenience or for a functional reason.

Beyond my quest for natural light and transparency, since 1987 the search for the best energy performance has led me towards large glazed facades 41 whose depth is either achieved by external features or a double skin, as appropriate.

Both options play with light and shade, transparency and reflection.

After three unsuccessful proposals 42, in 1989 I was allowed to design the first building with a double skin and to complete it, in 1992-1993, at 41

The idea of a rigid brick cladding suspended in front of an increasingly thick layer of soft insulation, which is also subject to thermal shock, runs counter to my instincts as a builder. It is only in recent years that the terracotta industry has finally been producing flush claddings made from small flat “flexible” tiles, allowing me to once again envisage using them.

42 Extension of the Banque Bruxelles Lambert on Avenue Marnix in Brussels (p: 1987. 01/183) — Extension of the Solvay Research Centre in Neder-over-Hembeek (p: 1987. 01/190) — Euroclear Operations Centre, Brussels; (p: 1988. 01/204). The thermal 51

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the junction of Rue Belliard and Rue de Trèves in Brussels 43 [01/225, Fig. 42]. An external clear glass envelope protects the wooden facade on a steel framework against noise and dust. The 0.90 m space that separates them, with its maintenance grating, serves not only as a thermal buffer but also as a large air duct recovering air from the offices. The improvement of this transparent building, in the administrative district of Brussels, with its reflective curtain walls and concrete or stone panels, surprises… and delights!

Firstly, in the same year, the Free University of Brussels, under the leadership of Hervé Hasquin, commissioned me to design the Medical Science Auditorium at the Erasmus Hospital with its single glazed envelope surrounding the lobby and the staircases around its enclosed space [01/270, Fig. 43], followed by Editions Dupuis for their Marcinelle headquarters [01/286, Fig. 44] where, benefiting from a North facing facade 44, the double skin space, which covers three temperature controlled atria, reveals all the depth of the structure and its glazed partitions on a wooden frame.

Next came the Catholic University of Louvain where Marcel Crochet, the Rector, and Raymond buffer double skins are also used here as corridors and stairwells on the facade (see website).

43 Brussimmo Building on behalf of Arbed-Sidmar.

44 There are only (external) blinds on the East and West end walls, with the South facade being blind and adjacent to a warehouse.

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Lemaire, the spiritual father of Louvain-laNeuve, allowed me to design the remainder of the Western area of the city and to plan the Aula Magna [01/291, Fig. 45 and 46]. For the first time, from the very first draft sketch, I was able to consider in detail the building’s physics in symbiosis with construction 45. The double skin covering the lobby rapidly became a necessity.

The large auditorium and its stage are specifically designed to make use of natural light 46.

Since then, I have continued, as issues have arisen, to use double skins 47. The most recent, and extremely delicate one, relates to the energy 45

Assisted by Filip Descamps and Paul Mees from Daidalos, as well as Peter Wouters from the BBRI, for acoustic, energy and lighting studies.

46 Taking advantage of my one week absence, to teach in Chile, the contractor was instructed to abandon the rooflights by the future operator. The ceiling still exhibits its sad closed eyes but I am confident that they will be opened one day, both for the sake of the quality of light in the room and on the stage, and for the obvious issue of energy savings.

47 Dexia Tower, Place Rogier, Brussels (p: 2002, c: 2003-2006.

01/ 301) — GlaxoSmithKline Research Centre in Rixensart (p: 1996, c: 1997-1999. 01/317) — CNP-NPM Headquarters in Gerpinnes (p: 1995, 1996-1997. 01/320) — INP Headquarters (Chilean Social Security Headquarters) in Santiago de Chile (p: 1997. 01/362) — Central Tower in Brussels (p: 1998.

01/364) — First Headquarters of Jan De Nul in Aalst (p: 2002, c: 2003-2005. 01/401) — Day Nursery in Watermael-Boitsfort (p: 2003. 01/459) — EUROPA in Brussels (p: 2005-2007.

2008-2016. 01/494) (see e-book at www.samynandpartners. com) — Namur Law Courts (p: 2007. 01/511) — BNP-Paribas-Fortis Headquarters in Brussels (p: 2013. 01/604) (see www.samynandpartners.com).

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refurbishment of countless housing blocks constructed in Europe in the period from 1950 to 1970, in the form of strips of 12 to 15 floors on long flat 11 m to 12 m deep rectangles with East and West facing facades. The thermal insulation and air sealing work (if not water-tightness work!) this involves must be carried out with minimal disturbance for the occupants.

This is why, for the building known as the “Villas de Ganshoren”, I am proposing to retain the existing facade in its entirety and to achieve the aim by adding wide balconies (thereby substantially increasing the comfort of the dwellings) and to add a second skin using clear double glazing with opening windows, but I am failing to convince the client [01/633, Fig. 47].

A double skin may occasionally be limited to a simple rain shield, as used in the renovation (in the quest for natural light) of an office building on the junction of Avenue Marnix and Rue du Trône in Brussels [01/489, Fig. 48]. The facade with its spandrels and false columns gave way to a wooden envelope over insulation with French windows and external wooden blinds on the balconies, protected by clear glass louvre slats.

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louvre slats A deciduous tree is the most natural and efficient way of providing protective shade in the summer, while allowing the sun’s rays to penetrate deep into a building, via the window, in the winter.

Where this is not possible, roller blinds, vertical blinds and shutters have always been used to provide protection in extremely sunny weather.

To be effective, these systems need to be placed on the outside and, in this case, they represent a key constructive element in the rhythm of the facade elements.

Generally shunned for almost half a century in our landscapes because of their cost (not just supply and installation, but also maintenance and upkeep), they are regaining their economic credibility in the light of current energy concerns.

This is why I proposed them, for the first time on a large scale, when working on the renovation of the ENI Headquarters in Rome in 1998 48 [01/375, Fig. 49 and 50], with its two East and West facing facades. Designed in 1959 by the architects Bacigalupo, Finzi, Nova and Ratti, this building, which was completed in 1962, is a real solar furnace and its enormous cooling units are unable to guarantee even the most basic level of comfort 48

The “Palazzo Mattei”, named after the President of Ente Nazionale Idrocarburi who disappeared in circumstances that are still a mystery today. The project was abandoned when ENI decided to sell off its property assets.

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for its occupants in the summer, (unless they close the interior Venetian blinds!) and require them to use artificial lighting. Consequently, I took this opportunity to invent a system of very large glass shutters, pivoting on their horizontal axis (on the scale of Ancient Roman architecture: 3.6 m high, 7.2 m wide), with alternating horizontal stripes, spaced out in terms of their breadth, screen-printed on both sides and following the sun’s trajectory. This system allows occupants to be permanently protected from solar radiation without being deprived of either light or a view.

The project was not completed (this building still remains a refrigerator with its door open after more than 50 years!) and the design remained confidential until recently. In 2010, I was invited to design the new head office of AGC Europe 49 [01/577, Fig. 51 to 53] in Louvainla-Neuve for which I proposed this system. The reception was enthusiastic and a patent application was filed for the invention 50, which enabled me to develop the concept in the form of louvre slats, which completely protect the four facades 49

Asahi Glass Company acquired a stake in Glaverbel in 1981, whilst allowing it broad autonomy in terms of management.

See: Philippe Samyn and Jan De Coninck AGC Glass Building, Tielt, Lannoo, 2014 (available as an e-book, at www.samynandpartners.com).

50 The Belgian patent application was filed on 2012.01.09 and the international patent application on 2013.01.09.

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(aligned strictly with the four cardinal points) of the square building, on a 1.35 m grid.

Horizontal in the North and South (twelve 30 cm wide louvre slats for each 3.6 m high floor) and vertical in the East and West (four 33.75 cm louvre slats for each 1.35 m module), they are supported by a very delicate bead blasted stainless steel structure, with a maintenance and safety passageway that keeps them away from the facade. Rods operated by small electric actuators enable them to be moved.

These servomotors, driven by climate data gathered on the roof (temperature, humidity, atmospheric pressure, wind speed, luminosity, cloud cover) control their orientation — independently for each facade.

In the North and South, the top four louvre slats on each floor are also controlled separately from the eight lower ones, to create a light shelf.

Closed during hot weather and open in cold but sunny weather, open when it is cloudy or very windy, the louvre slats are in a state of slow constant motion and create a dynamic interplay of light and shade.

All the building’s glazing is “Clearvision” — of course. The envelope’s glazing, behind the louvre slats, is equipped with the “vacuum” coating offering the best balance of thermal insulation (U= 1.0W/m² °K), light transmission (TL = 75 %) and color rendering index (CRI = 97 %).

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This means that the building is “near zero energy” (NZE) 51 while being fitted with virtually transparent glazing, as the energy saving made on electric lighting is far above that which could have been achieved with more thermally efficient but less transparent glazing.

White fabric blinds on the inside of the envelope complete the system for managing luminance 52 and luminous contrast.

At night, the closed louvre slats (as well as the blinds, if required) create a white surface that reflects the artificial interior lighting, making it more comfortable for occupants and improving the energy balance, whilst also providing sideways views of the outside world.

The result is so convincing that, when visiting the building in 2015, Jan Piet and Dirk De Nul themselves effectively adopted the louvre slats for their second new headquarters in Aalst [01/571, Fig. 54].

The louvre slats can also be opaque, but at the expense of light transmission, if there is also a need for shade in addition to sun protection.

This is the system earmarked for the renovation, transformation and extension of the Maison de 51

The NZE (Nearly Zero Energy) rating equates to a building, the energy consumption of which is almost zero, without taking account of the energy needed by equipment associated with human activity.

52 1000 to 4000 Cd/m² for a window, 70 to 80 Cd/m² for white paper at 300 Lux. 58

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la Culture de la Province de Namur 53 [01/628, Fig. 55 and 56].

The new facades, in extra clear glass with a U value = 1.1 W/m² °K and oak frames, are protected from the sun and rain by overhanging sills and white Z-shaped lacquered steel louvre slats, creating numerous lines of shade that punctuate the facade. the mashrabiya Like a mashrabiya, an envelope must sometimes filter light and the view where the latter wishes to be discrete or suggestive. This is true for both the external patchwork facade of old recycled oak frames and the glass facade of the “lantern” at the headquarters of the Council of the European Union 54 [01/494, Fig. 57 and 58].

The patchwork of old oak frames acts as a lampshade for the “lantern”. It literally “disappears” at dusk when the latter is illuminated 55.

53

This building by Victor Bourgeois (1897-1962), which was completed in 1964, has bronze and reflective glass curtain walled sections of its facade. Elegant and popular at the time, they are in a poor condition and their energy performance is weak.

54 Jean Attali and Philippe Samyn, EUROPA. European Council and Council of the European Union, Brussels-Tielt, CIVA and Lannoo, 2013 (see e-book at www.samynandpartners.com).

55 “Les vertus du patchwork et la facade du Conseil de l’Union Européenne” (“The virtues of patchwork and the facade of the 59

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From its first to its eighth floor, the “lantern” contains four large conference rooms, each surrounded by two tiers of interpreters booths accessed via eight levels of adjacent corridors.

On the ground floor, and on the ninth and tenth floors, a cafeteria and restaurants provide a view of the outside world. Finally, a curved fire escape staircase, serving all floors, stands the entire height of the “lantern”. The envelope requires a degree of transparency at the top and bottom for the view, and a degree of opacity around passageways and corridors to ensure privacy. This combination is achieved by using screen-printed panes of glass with varying levels of transparency between 33 and 75% 56.

The pattern reproduced on the panes must render their basic division visible and, therefore, the succession of sizes 57, but also, like an illusioCouncil of the European Union”), in Bulletin de la Classe des Beaux-Arts, Académie Royale des Sciences, des Lettres et des Arts de Belgique, 6th series, v. XVII, 2006, 7/12, pp. 323-353.

See also Jean Attali and Philippe Samyn, op. cit., pp. 67-92.

It was in 2003, for the first time, that I proposed using old recycled oak frames for the double facade of a day nursery in Watermael-Boitsfort (01/459).

56 Each quarter of the 42 elements, made from segments of elliptical cones forming the envelope, comprises 14 trapezoidal curved panes of glass with curved horizontal edges, equalling a total of 588 panes with different dimensions and degrees of transparency (see also Jean Attali and Philippe Samyn, op. cit., pp 109 to 158).

57 Dom Hans van der Laan (1904-1991): Le nombre plastique, quinze leçons sur l’ordonnance architechtonique (The plastic 60

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nist, exaggerate the space’s outlines. The pattern that I have chosen is made up of sloping lines inclined at ¾ from the horizontal, positioned alternately in one direction and the other. In the first direction, the strips have a constant width of 5 cm with a variation in the gap between them of between 5 and 15 cm, while in the other direction, the strips are 7.5 cm wide, with a gap of between 2.5 and 12.5 cm. The distance between the strips is at its smallest in the centre of the “lantern’s” surface and increases incrementally as the strips approach its base or apex, resulting in a reduction in transparency as the “lantern” expands and, conversely, an increase in transparency as it narrows at the top and bottom. The mashrabiya effect intensifies in the fire escape with a succession of highly perforated steel sheets, both hangars and parapets, real curved mantillas coiling up vertically from one floor to another behind the convex envelope.

“Coloured mirrors” With “natural light” having entered the building with a minimal loss of quality, there it is inside, number, fifteen lessons on architectural rules), translation by Dom Xavier Botte, Leiden, E. J. Brill, 1960. This is the only established theory relating to the rules governing the proportion of spaces in relation to visual acuity and human morphology (see also the works of Gérard Cordonnier, 1924).

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bouncing either directly or in a scattered manner off all the surfaces that it falls on. These surfaces themselves act as diffuse mirrors re-emitting a small proportion of the natural light that reaches them, and their colours “tint” the objects contained in the space that they enclose. It all takes place as if our perception of nature and the living world make the reflections of “natural” materials, such as wood and stone, attractive and soothing to us.

The same applies to patterns involving fauna and flora, even when reproduced in paint on paper or fabrics. The same is not true of the surfaces of walls painted in large blocks of uniform colour, which are the manifestation of an abstract human act. If they are not intended or anticipated artistic expressions placed on view, they become more insidiously intrusive and disturbing, the more discrete the colour aims to be. This is how “off white” shades (whose name is very appropriate) or “tinted” greys seriously disrupt the perception of a space. For a long time, I have been expressing a desire for paint that is truly white, like that used by painters (in gouache, acrylic or oil) or like talc coated paper, or more simply like a whitewash, as no industrially produced paint can do this. This was still the case in 1997, and it is very annoying that the past century’s industry is still as deficient in this respect. Consequently, I turned to “pure” greys, which are supposed to be a simple mixture of white and black, and it is to François Cornélis, 62

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the Chief Executive of Petrofina at the time, that I owe the development of “pure grey” acrylic paints by its subsidiary Sigma Coatings, in 1998. This is not always as straightforward as it may seem, as black is only produced by a mixture of colours, which it is hard to calibrate 58 (and we know how much Rothko profited from this!). When these paints were finally ready, I proposed them to Hendrik Seghers, for whom I was renovating Castle Groenhof in Malderen [01/532, Fig. 59] at the time and he wrote: “maar dit zijn kleurspiegels!”, and how right he was!

As a result, I chose these “coloured mirrors” to suit the wall and room in question; a very dark grey in the stairwell to highlight a splendid Rubens, an almost black grey in the only surviving Louis XVI style room to make the woodwork and its light grey mouldings shimmer, greys bordering on white in the bedrooms, etc. he was equally convinced when I proposed painting the facades in a grey with 60% black 59. It 58

There is no doubt that the invention of the blackest of black, a colour that absorbs 99.965% of light, a paint made up of a forest of carbon nanotubes perpendicular to its surface, whether this is by the Belgian artist Frederic de Wilde (2010) or by Vantablack (2015), (for Vertical Aligned Nano Tube Arrays-Black) must be used in construction.

59 A large screen of louvre slats with photovoltaic cells following the sun’s trajectory protects the added terraces on the front of the Southern facades. A series of long borosilicate glass tubes containing solar thermal sensors form the pergola on the flat roof.

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changes colour depending on the time of day, the time of year and the weather! Since then, I have used these grey paints for all my projects.

When, at a later date, with a far smaller budget, Hendrik asked me to renovate the castle’s service quarters, I lined them with crumpled aluminium paper 60: a mirror or a mirror that reflects colour?

[Fig. 60]. And there you are, light that bounces back again. shutters, curtains, reflections and Lux Transparency goes hand in hand with reflection.

The atmosphere itself cannot be more transparent than in cold and dry weather and without backlighting (think of mirages: what a reflection!).

As for glass, even crystal clear, it is only truly transparent when you look at an illuminated scene from a space that is less well lit: from inside to outside via a North-facing window, or the reverse at night.

In traditional construction, shutters and curtains are closed at nightfall, or open on the spectacle of a full moon or a starry sky, on storms or even on snowfall.

60

At the same time, it forms a vapour barrier covering the insulated wall on the warm side, which is certainly technically orthodox and in line with the modern desire for technology. Be that as it may, a breathable wall is always preferable for a building that is regularly inhabited, which is not the case here.

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This darkening contributes to the intimacy of a room and is also useful in increasing its brightness by means of the reflection of artificial light. It saves us from the unpleasant “black mirror” effect 61 produced by glazing under indoor lighting.

Lighting here is still at least 250 to 500 Lux for the wealthy (for how much longer?) while it rarely exceeds 50 to 100 Lux for the poor 62.

Global glass canopies The fully open crowning oculus at the top of the 43 m diameter half-sphere of the dome of the Pantheon in Rome (125 A.D.) or the tall stained glass windows in Gothic cathedrals (48.5 m for the naves at Beauvais (1225-1272/1500-1548)) enables natural light to illuminate grand spaces with an infinite interplay of light and shade.

Oculi and large vertical glazing still form part of the architectural vocabulary, but the first large steel frameworks, which appeared from the second half of the 19th century onwards, enabled glass roof canopies to be created: covering an entire edifice, they opened up a new chapter in the art of building.

61

Unlike a semi-reflective two-way “white” mirror when looking towards a dark room.

62 During the day, both rich and poor benefit from illuminance of a maximum of 90000 Lux! 65

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Vast transparent roofs cover the first open air railway stations and large exhibition halls.

Complete glass canopies enveloped enormous closed spaces, such as that at the Crystal Palace of 1851 in London (39 m high) or the first large greenhouses at the Jardin des Plantes in Paris (1836), Kew Gardens (1849) or the Royal Palace of Laeken (1873).

The penetration of natural light into these open air or enclosed spaces is 60 to 70% (that of glass, when it is clean, minus the influence of its supporting structure) and the temperature there fluctuates freely, as in the Pantheon and in cathedrals.

It is very difficult to maintain a stable temperature there and to prevent draughts, as the envelope is glazed and has no thermal inertia.

In cold weather, the heat that is produced causes currents of rising air, which accelerates when the air cools by sinking along the outside walls.

In hot and sunny weather, despite sun shades, vents at the top and bottom of the enclosed space are needed to dissipate the heat produced by the greenhouse effect, even when using reflective glass with a low solar factor.

Large areas of glass can also cause acoustic discomfort, whether this is because of the noise that reverberates from them or that caused by heavy rain.

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Therefore, these thermal and acoustic issues have a decisive influence on the architectural composition and organisation of large complete single glazed canopies (U=5.7 W/m² °K) in order to help them retain their functional and environmental legitimacy. Where it is necessary to create a space that is climate-controlled in every way, which should be avoided in principle, the use of double glazing (U=1.1 W/m² °K) and, before long, vacuum glazing (U=0.3 W/m² °K) will enable thermal discomfort to be reduced, to a certain extent, during the winter, at the expense of significant energy costs, but still requires systems to “cut out” cold draughts along vertical glass walls.

This is why, for the atria of the new headquarters of KBC Verzekeringen 63 in Leuven [01/433, Fig. 61], glass tanks at the foot of the vertical glazing were included to re-heat the air from draughts before it flows into the space, and for the EUROPA building [01/494, Fig. 62], a finned heating tube is arranged along the entire inside of the double facade at a height of 5 m 64.

These are rare exceptions and complete glass canopies are always designed, more logically, with single glazing or a single skin.

63

Marc Dubois, Tussen binnenstad en spoor. Leuven 2003, Gent, Ludion. 2005.

64 An inner facade with a steel frame and an outer facade with a “patchwork” of oak frames.

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Any form of surface (with zero, positive or negative Gaussian curvature) 65 is geometrically achievable using triangles or trapezoids (with flat glass, as in the following examples, or conical, as for Europa’s “lantern”, being the usual approximation).

Nevertheless, the use for which a glass canopy is intended, its size and the physical performances 66 that are expected of it, as well as the quest for the lightest possible structure (within the bounds of flexibility imposed by the fragility of the glass) restrict this freedom.

Furthermore, the structure must be neither too slender vertically nor too low profile to limit the effects of wind, on the one hand (horizontal force of the order of 1 kN/m²), and dead load, on 65

The geometry of a curved surface is defined by R 1, its largest radius of curvature and R 2, its smallest, measured perpendicular to the tangent plane at each of its points, or by 1/ R 1 and 1/ R 2 known as the principal curvatures. The Gaussian curvature, which is the product of the latter (K = 1/ R 1 × 1/ R 2 ) defines the general form of a surface. Therefore, for quadric surfaces (the three-dimensional equivalents of two-dimensional ellipses, parabolas or hyperbolas) K = 0 where R 1 is infinite, as for an elliptic, hyperbolic or parabolic cylinder or a cone with an elliptical base; K > 0 where R 1 and R 2 are on the same side of the surface, as for an ellipsoid, an elliptic paraboloid or a hyperboloid of two branches; K < 0 where R 1 and R 2 are on each side of the surface, as for a hyperboloid of one branch (a diabolo) or a hyperbolic paraboloid (a saddle), illustrations and equations available at www.wikipédia “quadric”. This is also defined as mean curvature: 1/R m = (1/ R 1 + 1/ R 2) /2.

66 This also relates to fire behaviour.

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the other hand (0.2 to 0.3 kN/m² for the glazing, and then 0.3 to 0.7 kN/m² for the structure. i.e. a vertical force of 0.5 to 1 kN/m²).

Compelled by stiffness 67, structures are still frequently made from ordinary steel S235 68 as in the following examples. However, the use of ultra high-strength steel, long reserved for cables and now available in thin sheets (supported by the automotive industry!), is an absolute must for reducing the quantity of material. It involves replacing stiff glass with flexible membranes and results in new structural morphologies, on which I am currently working.

The canopy of the Comptoir forestier in Marche-en-Famenne 69[01/279, Fig. 63 to 65] made up of single trapezoidal panes with a reflective coating, forms a torus section (K > 0) on a wooden framework.

67

The modulus of elasticity E (which determines the stiffness of a material and is expressed in Pascals (Pa), or N/m²) is E = 210 GN/m² for steel, whatever its yield strength, and which varies from 235 MN/m² for mild steel to 2000 MN/m² for ultra high-strength steel.

68 The “strength” σ of a steel is expressed as a capital S followed by its yield strength in MPa (stress at which it stops being deformed elastically). It is currently possible to obtain sheets that are between 1 and 12 mm thick in S2000, and which are perfectly weldable.

69 Bulletin of the International Association for Shell and Spatial Structures, vol. 36 (1998), no. 2, August 118, pp. 73-82. Available as “01/279” at www.samynandpartners.be.

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It covers an industrial workspace and two masonry structures, one of which houses cold stores and the other offices and laboratories, which are heated in winter.

That at the Neanderthal Museum in Erkrath Mettman, Germany [01/290, Fig. 66] is a section of an elliptic cylinder (K = 0) covering the archaeological site. Misters spray water (hard water for a time) on the external surface, which is made from clear trapezoidal panes, both cooling the enclosed space and covering it, after some time, with a translucent limescale coating.

The canopy covering Petrofinaâ&#x20AC;&#x2122;s company restaurant, on Rue Guimard in Brussels [01/313, Fig. 67] is a cylinder in the form of a catenaryâ&#x20AC;&#x2030;70 (K = 0), with its rectangular double glazing panes being supported by small curved steel IPE80 profiles suspended from the adjoining buildings, providing it with shade.

Finally, the canopy of the exhibition tower at the Glass Museum in Lommel [01/469, Fig. 68 and 69] adopts the form of a cone with a circular base (K > 0). The double glazed panes with a reflective coating and the mesh of the fine structure of steel tubes that support them are triangular.Although the wooden framework of the Comptoir and the limescale coating in 70

The catenary is the form adopted by a cable crossing a horizontal span where it is suspended by its ends and subjected to a vertical force that is evenly distributed along its length.

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Erkrath reduce light transmission, they provide a certain degree of sun protection during the day and reflect artificial light at night while being filled with light from the outside. Conversely, as the tower in Lommel exhibits glass works of art along its spiral staircases, it needs to provide transparency and sparkle at night.

Polycarbonate 71 has the same light transmission properties as glass but is 35 times as flexible, 6 times as expandable, twice as light and, above all, more impact resistant. Used in the form of multi-walled panels, it offers thermal insulation of 0.875W/m²K with a color rendering index (CRI) above 97%, which also makes it a suitable material for canopies, despite its lower resistance to ultraviolet light.

As a result, I have used it for the walls of sports halls at the Fire Stations in Enschede (p: 2003, c: 2005-2007; 01/450) and in Charleroi (p: 2014, c: 2015-2016; 01/569), but it is primarily to provide wonderful light in the small studio belonging to the artist Erik Salvesen in Ekenäs71

Polycarbonate, discovered in 1953 by Schnell, Bottenbruck and Krimm at Bayer AG, appeared on the market in 1958. Yet again, we had to wait for decades to witness the development of multi-walled panels with excellent insulating properties.

It has a density of 1.2, a yield strength of 60 MPa, a modulus of elasticity of 2 GPa and a thermal expansion coefficient of 70.10-6 °K-1 (compared to 2.5 – 40 MPa – 70 GPa and 1.2. 10-6 °K-1 respectively for ordinary glass).

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Tammisaari, Finland, that it proved to be extremely useful [01/561, Fig. 70].

On the outside, multiplex wooden crossbeams support openwork cladding made from wooden planks and a single-glazed canopy and, on the inside, there are multi-walled polycarbonate panels. plastiC membranes Since time immemorial, natural light has also been transmitted in a diffuse way through white canvas tents or filtered by basketwork or ropework meshes and nets.

The discoveries and inventions of the past century now enable us to create flexible envelopes made from transparent and watertight canvases and films, and even sheets, meshes or nets with variable permeability, as well as rigid envelopes made from translucent panels with excellent insulating properties. They open up new avenues for the art of building, once again playing with light and shade, transparency and reflection.

The use of PVC coated polyester fabricsâ&#x20AC;&#x2030;72, hitherto used for tarpaulins (and in particular to cover the cargo beds of lorries), has been tested 72

Hoechst in Germany was the main producer of them at the time, but has been gradually superseded by Serge Ferrari in Lyon, which has been producing the best performing tarpaulins since 1973, with fabrics that have an M2 fire classification.

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since the 1960s for outdoor tents and also to cover large enclosed spaces, beginning a new chapter in the art of building. These flexible surfaces, which can only have a negative Gaussian curvature 73, are light (1 to 1.5 kg/m² compared to 20 kg/m² for 8 mm glass), are produced as easily as boat sails and are easy to work with. They currently have a permissible strength of 100 to 150 KN/m. Even though they are white, their light transmission (LT) is less than 10%.

PTFE 74 coated fibreglass fabric appeared in the early 1970s 75. It has the same mechanical properties as modern polyester — PVC fabric, is a little more transparent, fire-proof, less dirty, theoretically more sustainable but, stiffer and more fragile, and is difficult to work with.

Frei Otto (1925-2015) 76 was one of the first people to realise the benefits of these “flexible 73

At atmospheric pressure, flexible envelopes subject to internal pressure can themselves adopt all kinds of curves (yet another different chapter in the art of building).

74 PTFE: Polytetrafluorethylene, discovered by chance by Roy. J. Plunkett (1910-1994) in 1938, at Dupont.

75 It is the result of a collaborative effort by Dupont, OwensCorning, Birdair and Saint-Gobain.

76 Frei Otto (ed.), Tensile Structures, Vol. 1: Pneumatic Structures; Vol. 2: Cables, Nets and Membranes, Cambridge (MA), The MIT Press, 1967/1969 (original version in German, 1962/1966).

As an architect (1925-2015), he also studied large tensile shapes in the form of steel cable nets and used them for the West Germany Pavilion at the Montreal universal exhibition in 1967 and then for the roof of the stadium and swimming pool for the Munich Olympic Games of 1972. These costly and complex 73

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canopies” for architecture, in the 1960s, and methodically developed the grammar and vocabulary for them. He specifically studied various minimal surfaces made possible with the aid of a film of soap on a closed contour 77.

The material of these surfaces (still with a negative Gaussian curvature, except for the plane) with a constant thickness is subject to constant stress in all directions at all points.

It is impossible to find more efficient forms for supporting their own weight, but they are not all efficient at absorbing the other loads to which the membranes are subjected. What is more, tents are always made from assembled strips of fabric and formed from a weft and a warp thread with different strengths (σ) and stiffnesses (E) in both directions 78. Therefore, this minimal structures, paradoxically heavily encumbered by their fittings, have subsequently been very rarely used except for a few large aviaries. Nevertheless, in 2009, they gave me the idea of nets made from sewn para-aramid rope.

77 It was the Belgian physicist Joseph Plateau (1801-1883) who carried out the first research into minimal surfaces with the aid of films of soap resting on a metal wire. He discovered the minimal surfaces of revolution under internal pressure (with a constant mean curve, not zero as demonstrated by Charles Eugène Delaunay (1816-1872)): the plane, the sphere, the cylinder, the catenoid, the onduloid and the nodoid. See also the works of D’arcy Wentworth Thompson, including On growth and form, Cambridge University Press, 1917.

78 Except for “pre-stressed” polyester — PVC fabric, invented by Serge Ferrari, in Lyon, in 1973.

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surface is not, strictly speaking, achievable in fabric.

You needed to be very open-minded in 1989 and bold, like Guido Ghisolfi 79 to agree to me completely enveloping his Research Centre, “M&G Ricerche” in Venafro [01/222, Fig. 40 and 71], in a closed textile structure (polyester-PVC).

The large enclosed space is cooled by fresh air taken in at the same level as the water in the surrounding lake.

This project was a success and enabled me to subsequently design and occasionally create other textile structures 80 including the BrusselsErasmus metro station with its fibreglass / PTFE fabrics and transparent stainless steel mesh facades [01/283, Fig. 72].

Aided by our powerful digital modelling tools, it is interesting to start examining new forms of “minimal surfaces” for membranes, whose 79

(1957-2015) Vice Chairman of the Mossi & Ghisolfi Group founded in 1953 in Tortona, Italy by his father Vittorio. SINCO Group, Tortona, Italy. All the more since there were no other examples on earth at the time, other than Frei Otto’s Diplomatic Club, in Riyadh.

80 Water tower, national monument in Nouakchott, Mauritania (p: 1989. 01/242) — Motorway service station, Wanlin (p: 1994, c: 1995. 01/314) — Courtyard roof, Alden Biesen Castle (p: 2001. 01/425) — Spy motorway service station (p: 2005, c: 2007-2008. 01/497) — Belgian Pavilion in Shanghai (p: 2009.

01/555) — Bastogne Historical Centre, Mardasson (p: 2009.

01/557) — Glass canopy for the National Bank in Brussels (p: 2012. 01/586). See www.samynandpartners.com.

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strength (and/or thickness) varies as desired over their surface (for example, in perforated metal sheets) or, for textiles, whose strength/stiffness is differentiated in the warp and weft, or even for sewn nets made from para-aramid or HPPE rope 81. These surfaces also have the virtue of not needing to be pre-stressed in order to acquire and maintain their shape.

Consequently, in 1987, for the vast atrium of the extension of the Solvay Research Centre in Neder-over-Heembeek [01/190, Fig. 73], I designed a membrane of this kind, ultra light, in transparent ETFE film 82 on a para-aramid net.

I then had to wait until 2008 and the competition, which we won, for the “East Vesuvio” 81

The para-aramid in question here (PPD-I) was discovered in 1965 by Stéphanie Kwolet and Hubert Blades at Dupont.

It was launched in 1971 under the brand name Kevlar. This was followed in 1978 by Twaron from Akzo (now produced by Teijin). It has a breaking strength of 3000 MPa (greater than the best steels but, with a density of 1.45, it is 5.5 times lighter) and a modulus of elasticity of 100 GPa. It has now been surpassed by “ultra high molecular weight polyethylene” (HMPE or HPPE) whose fibre was invented by Albert Pennings in 1963 and marketed from 1990 onwards by DSM in the Netherlands under the brand name Dyneema.

Its fibre is lighter, with a density of 0.97, a yield strength σ of between 1400 and 3000 MPa and E = 100 GPa. Finally, carbon fibre ropes are starting to make an appearance, while awaiting carbon nanotubes with a breaking stress of 50 GPa and 6 times lighter than steel!

82 Ethylene tetrafluoroethylene, produced by Solvay, among others. I developed this membrane with PTL (Plastiques and Textilles Lyonnais), it has light transmission of more than 90%.

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High Speed Train station on the Rome-Reggio di Calabria line, with a hall beneath an ultra light and flexible parabolic cylinder framework, made from an ultra high-strength steel structure covered with an ETFE film, with record light transmission of 88%! [01/552, Fig. 74].

The entire structure is so light that wind forces take precedence over the region’s significant seismic forces. The ventilation here is natural to guarantee a comfortable interior space and “glazed cooling tanks” complete the system locally.

This was followed, in 2009, by the N’Gozi Cultural Centre project in Burundi [01/567, Fig. 75], which is particularly close to my heart, as it forms part of a cooperation project with Belgium. The country’s material poverty contrasts starkly with the lively and refined culture of its people, which is expressed, among other things, in their sumptuous textiles and basketwork and their expertise in building shelters from leaves and twigs 83. This is why I propose using only para-aramid or HPPE rope, supplied on reels, and then knotted by the villagers to create enormous nets hung from the euca83

It is time to stop plundering the eucalyptus forests, which abound with local furnaces producing the mediocre bricks that are used to build poor quality Western style buildings, which bear no relation to either the country’s nature and climate, or culture.

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lyptus trees on the site, from which gigantic huts (naturally ventilated and lit) made from leaves and twigs are in turn suspended 84.

The concept of a large HPPE net covered with an ETFE film was reproduced, in 2010, for the large events hall in the quarry in Zhoushan [01/574-2, Fig. 76].

Although these inexpensive, extremely light and transparent, virtually stain-resistant minimal structures, which disappear in a blaze and are made from para-aramid or HPPE nets, covered — or not — with an ETFE membrane, are the most promising and workable (since 1990 !), they are still only plans on paper. East Vesuvio and Zhoushan will consequently be “firsts”.

This is a reminder of the slow speed at which the construction industry progresses. Facilitating research and development, including outside laboratories, by experimenting with actual structures for their own use, would be likely to energise it, but above all to give property investors and other patrons confidence.

84

The shape of the surface and mesh of the nets are designed such that they bear loads using as little (expensive) material as possible. Being suspended, the huts are no longer subject to the instability that characterises them when they stand on the ground. Therefore, they can be far larger than all those built to date (the Bantu huts in the Transvaal in South Africa).

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perforated sheet membranes The metal sheets used in stainless steel mesh or perforated sheets certainly enable visual and sun protection screens to be created, but are, above all, very effective as a windbreak.

This is how the metal deployed protects the motorway service station 85 at Houten in the Netherlands [01/363, Fig. 77], and the stainless steel meshes adorn the shutters on the first floor terrace of Castle Groenhof [Fig. 59] and protect the platforms at Erasmus metro station [Fig. 72].

It was at “De Nul”, in 2001 that I discovered the benefits of flat perforated sheet for the facade of the ground floor car park and the glass canopy ceiling of the entry awning [Fig. 23] and immediately used it for the square terraces and the renovation of social housing in Rue des Minimes, close to the Brussels Law Courts [01/421, Fig. 78] as well as Toren College, on the bank of the Lys in Kortrijk (01/510; p: 2006-2015, c: 2016-2018).

It started to become a “structure” as I shaped the sheet to surround the Fire Station in Charleroi and allowed it to extend onto the roof to create a tall parapet [Fig. 37].

I gradually became aware of its structural potential, in particular when designing the fire 85

As well as those at Orival (p: 1998, c: 2000-2001, 01/365) and Hellebecq (p: 2000, c: 2001-2002, 01/385), and the “noses” of the vaults covering the platforms at Leuven station (p: 1999-2001, c: 2002-2008, 01/389).

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escape staircase in the “lantern” of the Europa building, which is suspended from a 1.5mm thick 50%-perforated sheet made from ordinary steel S235 86 [01/494, Fig. 79], and even when extending the winery vats at Château Cheval Blanc in SaintEmilion [01/542, Fig. 80], both to support the roof and its light shaft and to provide protection against falling.

It becomes a structural element in its own right, when it replaces the diagonals in lattice beams to absorb the shear force, whilst also providing climate protection and counteracting falls 87. I designed two footbridges based on this principle in 2010 88, but was not able test the concept until 2016 for the exercise tower at the Fire Station in Charleroi [Fig. 81].

Owing to the emergence of ultra highstrength steel, it would be interesting to envisage creating enormous perforated sheet steel tents, like those created, in solid sheet by Vladimir Shukhov 89 in Nizhny Novgorod in 1895 and 1896 86

What is more, it does not require any fire protection as it is stressed to less than one-twentieth of its yield strength.

87 A metal sheet used “levelled”, which is more “ethical” as there is no waste from the holes in the perforated sheet, can also be used with less structural effectiveness.

88 The footbridge over the railway tracks at Leuven Station — third version (p: 2010, c: pending, 01/415-3) and two large footbridges in Ghent, over the canal and the motorway (p: 2010, 01/575).

89 Vladimir Grigorievitch Choukhov (1853-1939).

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but, to the best of my knowledge, never again since then.

While a polyester-PVC or fibreglass-ETFE membrane (with light transmission of just 10%) cannot reasonably cover a span of more than 20m, a 1mm-thick, 60%-perforated steel sheet membrane coated with a transparent ETFE film (therefore with light transmission (LT) â&#x2030;Ľ 55%) could easily cover a span of more than 50m using an S690 steel and up to 70m using an S2000 steel! from candles to Leds At the end of the day, when night falls, artificial light sources enable manâ&#x20AC;&#x2122;s activities to continue.

In effect, it is not possible to rely on a full moon, whose luminous flux is just 0.25 Lm, only providing illuminance of 0.25 Lx on the ground.

Outside, the large wood fires, around which people settled, took over with their magical interplay of light and shadow but, inside, our ancestors had to be content with light from the hearth and candles, whose luminous flux reaches approximately 10 Lm (illuminance of the order of around ten Lx for a candle placed on a table): the empire of the shadow.

Fortunately, the illuminance needed for a comfortable illuminated atmosphere also

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decreases with the colour temperature 90. Artists and craftsmen are called upon to spread the light emitted by these low-power but vibrant sources 91.

They create crystal chandeliers and play with mirrors beneath very high ceilings.

18th century oil lamps, gas lamps and kerosene lamps, and other flammable sources marketed in the 19th century offered better efficacy and more significant luminous flux. In the towns and cities, buildings were gradually connected to gas distribution networks 92 for lighting and heating. This network joined those for sewage 93 and water 94 and was followed by electricity and telephone networks at the end of the same century, and then by fibre optic networks at the end of the 20th century. Street lighting was born, improving not only the safety of city streets but also that of buildings, whose intrusion protection mechanisms were reduced. Major urban centres 90

91

92 93

94

This is why, according to Kruithoff, 15 Lux is sufficient for candle light (Tc=2000°K), and 50 Lux for incandescent light (Tc=2400°K), while we need 300 Lux for a colour temperature (Tc) of 3000°K (halogen) and more than 500 Lux for a colour temperature (Tc) of 5000° K. The eye’s sensitivity to light, which reaches its maximum in broad daylight for the wavelength corresponding to yellow (555nm) shifts, at night, to that of blue (470 nm) and is zero for wavelengths below 380 nm (ultraviolet) and above 770 nm (infrared).

The luminous efficacy of a candle is only 0.3 Lm/W. In London in 1812, in Brussels in 1818.

Vaulting of the Senne in Brussels was only completed in 1871.

The supply of water to each building is relatively recent in Belgium where it only became organised from 1860.

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distributing goods and services organised themselves and modes of transport developed.

Night-life took on a whole new dimension, with reading and the acquisition of academic knowledge in particular. The bad habit of using electric lighting during the day was also very soon adopted.

Urban buildings, which were now â&#x20AC;&#x153;connectedâ&#x20AC;?, were gradually but profoundly changed by this, while isolated buildings outside the towns and cities still retained their autarchic and protected physiognomy for a long time. Urban housing, for example, was able to dispense with its coal cellar, waste and compost heap, pantry, laundry and linen store, cellar and attic, as all the functions once performed by these ancillary spaces were now ensured by supply networksâ&#x20AC;&#x2030;95.

Electric lighting does not produce either flames or gaseous emissions and greatly reduces health hazards and the risk of fire. Structures can become water- and airtight, making the necessary air renewal a mechanical possibility. Ceiling heights can also be reduced and floor areas made deeper.

95

The system reaches its limits, and increasingly loses its balance with nature. In particular, the cost of networks per unit of floor area increases exponentially as towns and cities expand, resulting in either social isolation, or the collapse of urban finances (see: The vertical city, op. cit., footnote no. 16).

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Industrial production of the incandescent filament bulb, at the end of the 19th century, followed by that of fluorescent tubes in around 1930, also revolutionised our lifestyle and construction methods. The incandescent bulb 96, with luminous efficacy of 10 to 20 Lm/W and a standardised useful life of 1000 hours 97, provided luminous flux of 740 Lm for 60 W and a color rendering index (CRI) of close to 100%, as well as a colour temperature of between 2400 and 2700°K. It became the universal lighting source.

Fluorescent tubes are even more powerful, with luminous efficacy of 80 to 100 Lm/W (for example, luminous flux of 3000 Lm for 36 W), a usable life that can reach up to 12000 hours and a colour temperature of between 2700 and 6500°K, as required. These performances are achieved at the expense of a standard color rendering index (CRI) of just 80%, which, for a long time, restricted their use in industrial buildings or offices.

However, there are tubes with a color rendering index (CRI) approaching 95%, (but with a loss of luminous efficacy of 5 to 10%). Their quality of light, although a little “colder” (4500°K instead of 2700°K), is as good as that of the incan96

It is virtually no longer manufactured, as its sale was permanently prohibited within the European Union on 31st December 2012.

97 This planned obsolescence by the Phoebus cartel from 1924 onwards, represents a technical compromise between luminous flux, luminous efficacy, color rendering and usable life.

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descent bulb. As a result, the fluorescent tube was clearly the most ethical light source for diffuse lighting, until the end of the 20th century.

Electricity generation, which was very local at the beginning of the 20th century, gradually became concentrated, with its distribution being handled by autonomous networks of very highvoltage cables to limit losses 98. Failures of these local autonomous producers and successive oil crises led, from the 1970s onwards, to the interconnection and densification of networks.

Following interminable negotiations, a compromise was reached, by virtue of which the miracle of electricity delivered its power at a standard voltage of 220 Volts in a star configuration, or 380 Volts in a triangular configuration 99. All electrical appliances, including lights, are now designed for these voltages.

The nature of light sources also shapes the styles of building on the planet. Areas that are still economically dominant (Europe, the United States, in particular) and countries governed by dictators with significant energy resources, like 98

It should be noted that the power is equal to P = V.I (Difference in potential multiplied by the intensity of the electric current) and that heat losses are equal to ΩI² (resistance Ω of the conductor multiplied by the intensity of the electric current).

Therefore, with constant power carried, a 10-fold increase in V results in a 100-fold reduction in losses.

99 IEC standard 60038, 6th edition, 1983, “IEC standard voltages” takes these values to 230 V and 400 V. 85

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the USSR a short time ago, are frequent users of luxurious halogen bulbs and their flattering light for homes, as well as for buildings dedicated to shopping, culture or leisure pursuits. This will not last for much longer.

Fluorescent tubes are commonly used for workplaces. What a contrast with geographic areas that have been left behind, such as Africa, South America and large parts of Asia! Here, energy insecurity, for whatever reason, forces people to almost exclusively use fluorescent tubes, which are so much more efficient. This nocturnal atmosphere, which we see as “primitive”, actually represents a particularly ethical use of available energy resources and technologies.

Light-emitting diode bulbs (LEDs) 100 slowly appeared in the 1990s, becoming potentially the most effective light source to date, with luminous efficacy of 80 to 150 Lm/W, a usable life that currently exceeds 80,000 hours (approaching 100,000 hours) and a color rendering index (CRI) that has already reached 95% for certain LEDs, and is constantly improving. The new light source, requiring a low voltage power supply (12 or 24 Volts) is one of the embodiments of the third industrial revolution, which is vigorously driven by the Internet. It is consistent with local 100

DEL (Diode Électroluminescente) in French.

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electricity generation, which is freeing itself of the current losses caused by centralised production. Consequently, in the very near future, our buildings will be required to be powered by local generation (see note 97) of 12 or 24 Volts, in addition to a 230/400 Volt supply. This is the second giant leap in the quest for efficient and secure use since the emergence of the incandescent bulb. I find it hard to imagine the impact of this development on architecture.

The LED is also becoming the pixel for illuminated displays, the potential size of which is constantly increasing 101, as for the Dexia tower 102 [01/301, Fig. 82] or, as envisaged, on the prow cylinder of the “Maison de la Culture de la Province de Namur” [01/628, Fig. 55].

101

In 1977 in the United States of America, James P. Michell presented the first flat black & white television screen with several hundred LEDs. In 2004, the “Freemont Street Experience” display canopy in Las Vegas-Nevada comprised 12.5 million LEDs (with a length of 460 m, a height of 27m and an equivalent width).

102 The Dexia Tower, which I designed for Jean Michel Lauryssen, a Director of “Progex-Compagnie Immobilière de Belgique” and with Barbara Hediger for the lighting.

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Ch a pteR 3

Shade

Shade only exists because there is light.

The following thoughts refer to opaque material rather than to transparent material and to its reflections, which have been discussed thus far.

The contradiction is only apparent as it is not as autonomous objects that these two sorts of materials are of interest to architects, but in the way in which they represent industrial or handmade construction elements, produced and assembled to create a real building.

Yet, the majority of materials that architects work with are opaque: the structure is opaque, stone and brick are opaque, as are wood, steel and tilesâ&#x20AC;&#x2030;1. It was several thousand years ago that architecture appeared on earth as an independent 1

Of course there are buildings with a glass structure, but these are experimental or showcase projects, which are closer to, potentially inhabited, sculptures than to architecture. The glass sculpture in front of the head office of AGC in Louvainla-Neuve [Fig. 1] is an example of this.

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discipline, and its fundamental rules apply more or less explicitly to opaque materials. The role of light in architectural modelling is, first and foremost, to define the spaces, then to “sculpt” the walls using the shadows cast, and finally to locally cross the latter, by means of openings, which are necessarily limited in terms of their number and extent.

It is only quite recently that the development of glass technologies has enabled transparency and reflection to play a more significant role in what a building expresses in its appearance. Nevertheless, all these elements, whether they are opaque or transparent, necessarily obey the same rules that govern a sound construction and are frequently referred to by the wonderfully ambiguous term “best practices”.

One of these rules is particularly close to my heart: the “shadow line” rule. It is derived from construction common sense but takes its name from what light reveals about it, and that is what gives it its place here.

Far from being just a secondary modelling detail, the shadow line underpins the way in which we build, being intimately linked to two fundamental concepts of architectural form: “drawing” and the “joint”, which will be examined below.

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The shadow line The “shadow line” rule can be expressed as follows: “except in the case of special conditions, which are precisely defined and restricted, all construction elements subject to the influence of bad weather must be characterised in terms of elevation by a horizontal shadow line, which highlights the difference in the depth of the walls required by the law of construction.”

This rule applies to all construction elements, both opaque and transparent, but its expression is not the same for these two categories of objects.

For opaque materials, the shadow line is a single dark strip, whose width is proportional to the extent of the difference in depth. For transparent materials, it plays a part in the complex interplay of reflections by locally replacing the reflected image with a darker transparent strip.

The shadow line has a very long history.

At any time and anywhere, vernacular constructions 2 in high rainfall regions generally have a roof that overhangs the walls to protect them from rain, whilst projecting the “original” shadow line.

This arrangement is “translated” in stone by erudite ancient architecture, in the form 2

The Encyclopedia of Vernacular Architecture of the World (Paul Oliver ed., Cambridge University Press, 1997 ; in three volumes) documents the subject in a rigorous and comprehensive manner.

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of cornices, architraves and dripstones. On a smaller scale, since ancient material technologies essentially only permitted assembly by stacking up small pieces of stone or wood, construction common sense required each element to be set forward of the one it rested on: this is the principle of the “drip deflector”, which prevents water seeping into the joint, where it would surely damage the building.

The roof overhang remains entirely relevant in contemporary architecture, but without copying the shapes of the past. On the contrary, reflection can be developed further: as an overhang becomes ineffective for facades higher than two storeys, there is a need to create additional protection using strips, continuous or not, distributed evenly over their height (maintenance passageways, terraces, etc.).

The emergence of waterproof materials such as metal sheets (copper, zinc, bronze, steel alloys, aluminium, etc.), composite material panels (PVC, polyester, butyl, EPDM, etc.) and large expanses of glass 3 does not call into question the 3

In the 19th century, the first glass roofs on a metal frameworks gave rise to the invention of “pure linseed” sealant, a mixture of chalk and linseed oil, whose use rapidly spread to all glazed panes, both to guarantee their water-tightness and to improve their rigidity. The glass remains mechanically attached by chocking with small nails for wooden frames and with a glazing bead for metal frames (steel, aluminium, bronze, copper).

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need for drip deflectors, in the form of overhanging sills, bevelled cladding, standing seams or profiled weatherboarding.

However, from the 1950s onwards, we witnessed the appearance of flexible and watertight sealants (in plastic, such as PVC and acrylic, in elastomers, such as polyurethane, polyester, polysulphide and silicone, the most widely used product today). This silicone sealant sticks to the elements it connects, and permits the creation of any smooth monolithic shape, thereby “liberating” architecture from the “constraints” of weatherboarding.

However, this “liberation” is purely visible as it is accompanied by the heavy constraint of upkeep and maintenance. In effect, the surface of a facade made from uniform and coplanar panels is subject to soiling and damage, which is more visible the larger, smoother and more reflective it is. As everything is more visible, dust, rain streaks, or even silicone marks, there is a need for more cleaning… 4 What is more, produced by a “heavy” industry, which is rarely able to guarantee resupply in the medium or long term, this kind of structure is fragile, or even transient. Admittedly, cottage industries, which have recently emerged thanks 4

Paint on a continuous base does not display this weakness provided that, where it is outside, it is adequately protected from rain, which still involves the shadow line.

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to their “smart” tools 5 which are perfect for producing individual parts or small quantities, are able to guarantee the replenishment of surface components at a reasonable cost. However, the use of these kinds of high-tech maintenance processes can only be envisaged on three conditions: the surface needs to be divided into small elements, the architecture must tolerate or even favour differences in colour and/or texture and the joint between elements must be easily replaceable. From a statistical point of view, few buildings falling within the category of “monolothic” architecture currently satisfy these three conditions. drawing Although science and technology are destined to progress, this is not the case for art which, through our senses, is always searching for the same soul and spirit. Within this trilogy of “reperire, invenire, creare 6”, construction plays a paradoxical role. Although it has not progressed in terms of its lines and drawing (in effect, there is no conceptual difference between the drawing of ancient and contemporary architecture), it is 5

6

The production of objects by means of 3-D “printing” or “cutting” based on digital files produced by a “designer” has become commonplace.

Discover, invent, create: my motto.

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in the hands of men and its physicality bears witness to its era.

Drawing 7 needs to simultaneously comply with the intangible rules of proportions 8 and legibility to move people and contain within it an understanding of construction 9.

It is expressed within the scope of the seven perceptible orders of magnitude, from millimetres to kilometres with the metre at the centre, and calls to mind the seven octaves of a piano keyboard with the musical note A with a 7

8

9

Even that relating to “new” architectural programmes, including those associated with transport, work and even health, must comply with the same rules.

Rediscovered by Hans Dom van der Laan, (see footnote no 57).

They refer to Pythagorean 3/4/5 triangles and the ratio φ as derived from the equation φ = φ³ +1 and comply with the rules of proportion, which governs the architectural space (in three dimensions) in the same way the “golden ratio” φ as derived from the equation φ = φ² + 1, which governs the painter’s two dimensional space. This is how, as my drawing progressed, and in particular when dimensioning parts of a building, I learned the virtue of the basic dimensions of 135cm in plan and 180cm (4/3 × 1.35) in elevation, with their multiples and sub-multiples (in cm) 135 / 112.5 / 90 / 67.5 / 45 / 22.5 / 11.5 / 5.675 / 2.8375… and 135 / 157.5 / 180 / 202.5 / 225 / 247.5 / 270 / 292.5 / 315 / 337.5 / 360…

The hand-drawn line that sets out the construction details as the drawing progresses as far as the workshop drawing is now powerfully complemented by an intelligent “digital model” (BIM: Building Information Modeling) with its three-dimensional components, to which various characteristics can be attributed by allowing it to be used by all the necessary software packages, such as those for structural calculations, the building’s physics or its costs. It represents a real revolution in the way of thinking about construction.

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frequency of 440 Hz at its centre (to the closest note).

It sets out, by means of lines, the contours of both the construction elements and the whole that they form, contours that are needed to define the precise measurements of the building with a view to being able to create itâ&#x20AC;&#x2030;10.

The joint Although a small object can be monolithic, a large object, piece of furniture or construction must be made up of various parts in the same or different materials.

These parts are linked to each other in countless ways, depending on the materials and use.

Knots, seams, adhesive, pins, nails, screws, welds generally closely link skins, fabrics, thin sheets, panels and profiles of all kinds to each other, forming the parts of a big object or piece of furniture. Their dimensions, on a decimetre and, at most, a metre scale, can be precise and subject to tight tolerances.

The same also applies to construction components: from blocks of stone, wooden beams and steel profiles to windows, doors and sinks.

10

A painter does not have the same goal and therefore, in the majority of cases, applies himself to creating and freely superimposing patches of light, shade and colour, with the contour being only the junction between two surfaces.

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Nevertheless, their dimensional tolerances combine, requiring a joint between them when they are assembled to create a construction.

Therefore, the latter, which is larger (on a decametre or a hectometre scale) is less precise. A joint generally has a constant width (in the order of cm) and always connects two parallelepiped or cylindrical volumes, whatever their relative positions or the form and materials used for their components.

This joint is central to the art of building. It needs to be thought about and designed with the greatest care from the initial drawing stage, so much can this be decisive in the actual construction details and materials envisaged. It also needs to be designed to enable a component to be replaced without damaging those around it, as well as the construction to be dismantled.

Where it relates to two components attached to each other, the joint is the connecting element or goes hand in hand with it.

In this way, mortar provides three dimensional connection for blocks and bricks, of stone, earth or terracotta, whilst forming the joint. It also guarantees air-tightness and/or water-tightness.

Components must have a minimum thickness to do this: of around a decimetre. A network of shadows is always accompanied by projections in the plane or outside the latter, both of the joint and the components.

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Pins, tenons and mortices, nails, screws, bolts or rivets link the rigid components made from wood, synthetic materials or metal, layered on top of each other by means of a plane forming a permeable joint. One of the components always casts a shadow line on the other, due to its thickness. Components that are too thin, metal sheets in particular, distort and result in mechanical assemblies that cannot be dismantled (such as rivets) and are as unattractive as they are transientâ&#x20AC;&#x2030;11, with streaky and irregular shadows: this is where there is a need to brace them or weld them together.

A joint is of a completely different kind where it relates to two components attached to a third, which is generally thin or very thin: the â&#x20AC;&#x153;claddingâ&#x20AC;?.

The skill lies in making the joint invisible, without a shadow, as is the case with strips of wallpaper hung side by side on a plastered wall or marble slabs placed alongside each other on a mortar bed (on a floor or wall).

The joint must be a few millimetres to a centimetre wide in the case of ceramic tiles, in order to negotiate the less precise dimensions both in plan and thickness, the shadow there is diffuse.

11

The same is not true of the assembly of panels for cars, boats or planes built in workshops with great precision.

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Epilogue

Shade and transparency are sometimes diffuse, divided or complete or even the sources of optical illusions 1.

When diffuse, they temper the drawbacks of light that is too bright or reflections (and soften colours), just as sound absorbing materials do for noise that is too loud and for echoes.

When divided, by the slow movement of clouds, rain or snow, the shimmering of water or the foliage of a tree, they track the passage of time.

They are different again under the influence of a point source of light, vibrant when exposed 1

We are permanently subject to them. New illusions are regularly discovered like, in 2011, the “Flashed Face Distortion Effect” discovered by Sean Murphy, a psychology student at the University of Queensland in Australia (see also “Optical Illusions” on Wikipedia). Therefore, there is still so much to discover on a metric scale as there is on the level of the atom or the cosmos.

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to a flame and immobile beneath an electric light.

Reflection is to transparency what shade is to lightâ&#x20AC;&#x2030;2.

Philippe Samyn.

The 1st of September 2016.

2

It is for aesthetics what music is to silence.

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List of figures

Fig. 1. — The glass sculpture in front of the head office of AGC in Louvain-la-Neuve; p: 2010, c: 2011-2014 (01/577).

Fig. 7. — Average annual daylight in Belgium (100% = 1100 kWh/m² year).

Fig. 8. — Lujiazhi Cultural Creativity Garden Zhoushan.

Cultural coffee shop and its photovoltaic canopy, Zhoushan, China; p: 2019, c: 2015-2016 (01/594).

Fig. 2. — The efficiency and sustainability of a construction in line with the advancement of knowledge.

Fig. 3. — Daylight in LUX in Uccle (Brussels) for North, East, South and West facing vertical surfaces and the horizontal plane (with a maximum of 90,000 Lux at midday on the horizontal plane at the summer solstice).

Fig. 9. — Average annual daylight in Zhoushan, China (100% = 2100 kWh/m² year).

Fig.10. — Photovoltaic canopy, Houten Fire Station, The Netherlands; p: 1998, c: 19992000 (01/373).

Fig. 4. — Daylight in LUX in Uccle (Brussels) for NorthEast, South-East, South-West and North-West facing vertical surfaces (with a maximum of 90,000 Lux at zenith, on 21st June at midday).

Fig.11. — The 2200 children’s drawings in the fire station.

Fig.12. — Europa, headquarters of the Council of the European Union, Brussels; p: 2005–2008, c: 2008–2016 (01/494).

Fig.13. — EuroSpace Centre, Libin-Transinne; p: 2006, c: 2007-2008 (01/518).

Fig. 5. — Headquarters of CNP/ NPM, Gerpinnes; p: 1994, c: 1995-1996, (01/320). Photograph January 2016.

Fig. 14. — Photovoltaic facade of the Applied Sciences Building at the Free University of Brussels; p: 2009, c: 2017–2018 (01/570).

Fig. 6. — Photovoltaic panel production hall, Dison; p: 2011 (01/592).

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between light and shade, TRANSPARENCy and reflection Fig. 15. — Perspective cross section.

Fig. 26. — The large semireflective panes form vertical light reflectors for this office building, Brussels; p: 1999 (01/381).

Fig. 16. — Olivier Strebelle’s weather vane on the office building designed for Eric Boulanger, Waterloo; p: 1998, c: 1989-1990 (01/200).

Fig. 27. — Light sensors on the roof for the International Polar Foundation, Toronto, Canada; p: 2004 (01/477.)

Fig. 17. — The meeting room and its roof cupola beneath the weather vane.

Fig. 28. — Cross section.

Fig. 18. — The oculus in the ceiling of the entrance hall, below the meeting room.

Fig. 29. — Light ducts in the wooden columns.

Fig. 30. — Perspective drawing illustrating the set of mirrors on the European History House, Brussels; p: 2010 (01/573).

Fig. 19. — The mirrors in the window reveals of the offices of Samyn and Partners, Uccle; p: 1992, c: 1993 (01/265).

Fig. 31. — The barrels of natural light illuminate the dark rooms.

Fig. 20. — The mirrors in the window reveals and on the light shelves, Europa; p: 2004, c: 2008 to 2016 (01/494).

Fig. 32. — A wooden structural lattice supports the roof and distributes the natural light inside the crematorium, Aalst; p: 2010 (01/583).

Fig. 21. — The light shelves for the “Crystal” building, Brussels; p: 1992, c: 1996-1998 (01/260).

Fig. 33. — A heliostat with an elliptical mirror illuminates the heart of the crematorium.

Fig. 22. — Detail of the gratings.

Fig. 23. — The light shelves at the headquarters of Jan De Nul, Aalst; p: 2000, c: 2001-2002 (01/401).

Fig. 34. — The mirrors on the roof allow the crematorium to be seen from a distance.

Fig. 35. — 232 heliostats on the Guggenheim Museum in Helsinki, Finland; p: 2014 (01/619).

Fig. 24 — Anidolic reflectors for the headquarters of the Caisse Congés du Bâtiment, Brussels; p: 1997 (01/351).

Fig. 36. — Model.

Fig. 25 — Illustration of the efficacy of natural light reflectors.

Fig. 37. — The rectangular heliostat in the central cour-

102

List of figures tyard of the Fire Station in Charleroi; p: 2014, c: 2015-2016 (01/569).

headquarters of ENI — (Ente Nationale Idrocarburi), Rome, Italy; p: 1998 (01/375).

Fig. 38. — The courtyard of the Ferme de Stassart, Uccle (01/265).

Fig. 50. — The gigantic louvre slats protect the East and West facades from the sun.

Fig. 39. — The patios at the Fire Station in Charleroi (01/569.

Fig. 51. — The Head Office of AGC Glass Europe, Louvainla-Neuve; p: 2010, c: 2011-2014 (01/577).

Fig. 40. — M&G Ricerche, Venafro, Italy; p: 1989, c: 19901991 (01/222).

Fig. 52. — The louvre slats on the North and South, East and West.

Fig. 41. — OCAS, Zelzate; p: 1981, c: 1990-1991 (01/223).

Fig. 53. — Interior view.

Fig. 42. — Brussimmo, Brussels; p: 1991, c: 1992-1993 (01/225).

Fig. 54. — The louvre slats at the second new headquarters of Jan De Nul, Aalst; p: 2015-2016, c: 2017-2018 (01/571).

Fig. 43. — Medical Science Auditorium, Erasmus Hospital, Brussels; p: 1992, c: 1993 (01/270).

Fig. 55. — Maison de la Culture de la Province de Namur ; p: 2015, r : 2017-2018 (01/628).

Fig. 44. — Editions Dupuis, Marcinelle ; p : 1993, r: 19941995 (01/286).

Fig. 56. — The white lacquered steel louvre slats.

Fig. 45. — The Aula Magna, Louvain-la-Neuve ; p: 1999, r: 2000-2001 (01/291).

Fig. 57. — The patchwork of old oak frames, Europa (01/494).

Fig. 46. — The blind parterre with artificial lighting.

Fig. 58. — The “lantern” in screen-printed glass.

Fig. 47. — Balconies and double skin. Villas de Ganshoren, Brussels; p: 2016 (01/633).

Fig. 59. — Pure grey with 60% black and the photovoltaic screen at Castle Groenhof, Malderen; p: 1998, c: 1999-2000 (01/352).

Fig. 48. — The clear glass louvre slats, Avenue Marnix, Brussels; p: 2006, c: 2007-2009 (01/489).

Fig. 60. — Mirror and crumpled aluminium paper lining the walls of the annex at Castle “Groenhof”.

Fig. 49. — The screen-printed louvre slats ensure that light is radiated into the offices at the 103

between light and shade, TRANSPARENCy and reflection Fig. 61. — The glass “tanks” at the foot of the canopy, KBC Verzekeringen, Leuven; p: 2002 (01/433).

Fig. 73. — The ETFE film on a para-aramid rope at the Solvay Research Centre in Neder-overHeembeek; p: 1987 (01/190).

Fig. 62. — The finned tubes at the foot of the glass wall, EUROPA (01/494).

Fig. 74. — East Vesuvio Station near Naples, Italy; p: 2008, c: in progress (01/552).

Fig. 63. — The “Comptoir forestier”, Marche-en-Famenne; p: 1992, c: 1993-1994 (01/279).

Fig. 75. — The Burundians invited to “weave” their cultural centre in N’Gozi; p: 20092014 (01/567).

Fig. 64. — Night view.

Fig. 76. — The large ETFE para-aramid tent in Zhoushan; p: 2010, c: in progress (01/574).

Fig. 65. — Interior view.

Fig. 66. — The elliptic cylinder canopy at the Neanderthal Museum in Erkhrath-Mettman, Germany; p: 1993 (01/290).

Fig. 77. — The metal screens used at Houten, The Netherlands; p: 1998, c: 1999 (01/363).

Fig. 67. — The canopy with a catenary for Petrofina’s restaurant, Rue Guimard, Brussels; p: 1994, c: 1995-1996 (01/313).

Fig. 78. — The 3m “square” terraces, Rue des Minimes in Brussels; p: 2001-2007, c: 20082011 (01/421).

Fig. 68. — The conical canopy at the Glass Museum in Lommel, exterior; p: 2004, c: 2005-2006 (01/469).

Fig. 79. — The perforated sheets supporting the fire escape in the “lantern” of the Europa Building (01/494).

Fig. 69. — The stairs.

Fig. 80. — The perforated sheet columns on the winery vats at Château Cheval Blanc in Saint Emilion, France; p: 2008 (01/542).

Fig. 70. — Erik Salvesen’s studio in Ekenäs- Tammisaari, Finland; p: 2009, c: pending.

(01/561).

Fig. 71. — The interior space at M&G Ricerche (see also fig. 40), (01/222).

Fig. 81. — The exercise tower at the Fire Station in Charleroi (01/569).

Fig. 72. — Brussels-Erasmus metro station; p: 1995, c: 20012003 (01/283).

Fig. 82. — Dexia Tower, Place Rogier, Brussels; p: 2002, c: 2003-2006 (01/301).

104

Contents

Introduction

Our senses and the paradox

ChapteR 1 â&#x20AC;&#x201D; A Knowledge base Construction The world of economics Energy and society

ChapteR 2 â&#x20AC;&#x201D; Light, transparency And reflection Daylight Orientation and latitude Openings Glazing Two technical developments Laminated and toughened glass Mirros reflecting natural light Natural light sensors Water as a mirror A double skin Louvre slats

7 9 13 14 18 21

25 26 27 28 30 36 42 44 46 49 50 55

The mashrabiya “Coloured mirrors” Shutters, curtains, reflections and Lux Global glass canopies Plastic membranes Perforated sheet membranes From candles to LEDs

ChapteR 3 — SHADE The shadow line Drawing The joint

59 62 65 66 72 79 82 89 91 94 96

Epilogue

99

List of figures

101

Collection “L’Académie en poche” 1.

2.

3.

Véronique Dehant, Habiter sur Mars ? (2012)

4.

Richard Miller, Liberté et libéralisme ? Introduction philosophique à l’humanisme libéral (2012)

5.

Ivan P. Kamenarovic, Agir selon le non-agir. L’action dans la représentation idéale du Sage chinois (2012)

6.

7.

8.

9.

10.

11.

12.

Jean Mawhin, Les histoires belges d’Henri Poincaré (2012)

Xavier Luffin, Religion et littérature arabe contemporaine (2012) François De Smet, Vers une laïcité dynamique. Réflexion sur la nature de la pensée religieuse (2012)

Jacques Siroul, La musique du son, ce précieux présent (2012) Baudouin Decharneux, La religion existe-t-elle ? (2012) Jean-Marie Rens, ‘Messagesquisse’ de Pierre Boulez (2012) Jean de Codt, Faut-il s’inspirer de la justice américaine ? (2013) Bruno Colmant, Voyage au bout d’une nuit monétaire (2012) Philippe Manigart et Delphine Resteigne, Sortir du rang.

La gestion de la diversité à l’Armée belge (2013)

13. Hervé Hasquin, Les pays d’islam et la Franc-maçonnerie (2013) 14. Monique Weis, Marie Stuart, l’immortalité d’un mythe (2013) 15. Xavier Luffin, Printemps arabe et littérature. De la réalité à la fiction, de la fiction à la réalité (2013)

16. Myriam Remmelink, Éthique et biobanque. Mettre en banque le vivant (2013)

17. Marie-Aude Baronian, Cinéma et mémoire. Sur Atom Egoyan (2013) 18. Frédéric Boulvain et Jacqueline Vander Auwera, Voyage au centre de la Terre (2013)

19. Daniel Salvatore Schiffer, Métaphysique du dandysme (2013) 20. Philippe de Woot, Repenser l’entreprise. Compétitivité, technologie et société (2013)

21. Jacques Scheuer, L’Inde, entre hindouisme et bouddhisme.

Quinze siècle d’échanges (2013)

22. John F. May, Agir sur les évolutions démographiques (2013) 23. Yaël Nazé, À la recherche d᾽autres mondes. Les exoplanètes (2013)

24. Jean Winand, Les hiéroglyphes égyptiens. Aux origines d᾽une écriture (2013)

25. Frans C. Lemaire, Dimitri Chostakovitch. Les rébellions d᾽un compositeur soviétique (2013)

26. Baudouin Decharneux, Lire la Bible et le Coran (2013) 27. Bruno Colmant, Capitalisme européen : l’ombre de Jean Calvin (2013) 28. Françoise Meunier, Quel avenir pour la recherche clinique en cancérologie ? (2014) En anglais : Françoise Meunier, What is the future of cancer research?

(2014)

29. Jean Winand, Décoder les hiéroglyphes. De l’Antiquité tardive à l’Expédition d’Égypte (2014)

30. Jacques Joset, Louis-Ferdinand Céline : mort et vif... ! (2014) 31. Jean-Baptiste Baronian, La littérature fantastique belge. Une affaire d’insurgés (2014)

32. Valérie André, La rousseur infamante. Histoire littéraire d’un préjugé (2014)

33. Jean-Pierre Contzen, Les menaces venant de l’espace (2014) 34. François Mairesse, Le culte des Musées (2014) 35. Guy Haarscher, La Cour suprême des États-Unis. Les droits de l’Homme en question (2014)

36. Catherine de Montlibert, L’émancipation des serfs de Russie. L’année 1861 dans la Russie impériale (2014)

37.

Jean-Pol Poncelet, Une énergie dérangeante. Nucléaire : une controverse durable ? (2014)

38. Philippe Samyn, La ville verticale (2014) En anglais : Philippe Samyn, The Vertical City (2014)

39. François De Smet, Une nation nommée Narcisse (2014) 40. Jean-Pol Schroeder, Le jazz comme modèle de société. Livre-disque, avec la participation du Steve Houben trio (2014)

41. Jean-Pierre Hansen, Une quête de Graal (2014) 42. Hervé Hasquin, Déconstruire la Belgique ? Pour lui assurer un avenir ?

(2014)

43. Philippe de Woot, L’innovation, moteur de l’économie (2014) 44. Bruno Colmant, Crises économiques et dette publique (2014)

45. Samuele Furfari, L’énergie, de la guerre vers la paix et la stabilité (2014)

46.

47.

48.

49.

50.

51.

52.

53.

Samuel Wajc, Que faire de la mer Morte ? (2014) Gilbert Hottois, Le transhumanisme est-il un humanisme ? (2014) Benoit Frydman, Petit manuel pratique de droit global (2014) Xavier Dieux, Le marché bien tempéré (2014) Alain Eraly, Quand les mots construisent la réalité (2014) Marc Wilmet, Petite histoire de l’orthographe française (2015) Amand A. Lucas, Les savants d’Hitler et la bombe atomique (2015) Jean-Marie André, Fleuve jaune, papillons amoureux et musique classique de la Chine du XXe siècle (2015)

54. Françoise Lauwaert, Puissance et pouvoir de l’écriture chinoise (2015) 55. Jean-Pol Poncelet, À toute ardeur ! Science et technique sur le chemin de l’énergie (2015)

56. Jacques Pélerin, Wallonie, réindustrialisation et innovation.“Sortir par le haut ? ” (2015)

57. Jacques Joset, Louis-Ferdinand Céline : la manie de la perfection... !

(2015)

58. Daniel Salvatore Schiffer, Le clair-obscur de la conscience (2015) 59. Jean-Marie Frère, La résistance des bactéries aux antibiotiques (2015) 60. François de Callataÿ, Cléopâtre, usages et mésusages de son image (2015)

61. Anne Staquet, Descartes avance-t-il masqué ? (2015) 62. Guillaume Wunsch, Michel Mouchart et Federica Russo, Les limites de la connaissance en sciences sociales. L’explication mise en cause (2015)

63. Vincent De Coorebyter, Deux figures de l’individualisme (2015) 64. Daniel Droixhe, Fer ou ciguë ? Récits sur le cancer du sein au 18e siècle (2015)

65.

66.

67.

68.

69.

Véronique Dehant, Habiter sur une lune du système solaire ? (2015) Pierre Somville, Pour une esthétique du coeur (2015) Jean-Pierre Schaeken, Pic pétrolier, pic gazier sans cesse reportés (2015) Jean Creplet et János Frühling, Penser les soins de santé (2015) Frédéric Boulvain et Francis Tourneur, Pierres et marbres en Wallonie (2016)

70. Marc Wilmet, Il y a grammaire et grammaire (2016) 71. Pierre Petit, Patrice Lumumba. La fabrication d’un héros national et panafricain (2016)

72. Viviane Pierrard, Les colères du Soleil (2016) 73. Philippe de Schoutheete, La création de L’Euro (2016) 74. Pierre Somville, Brasillach écrivain, mal-aimé des Lettres françaises (2016)

75.

76.

77.

78.

79.

Roland Souchez, Glaces polaires et évolution de l’atmosphère (2016) Hervé Hasquin, Le soi-disant “Gladio belge” (2016) Francis Delpérée, J’écris ton nom, Constitution (2016) Christophe Van Staen, La Chine au prisme des Lumières françaises (2016) Jean-Paul Haton, La parole numérique. Analyse, reconnaissance et synthèse du signal vocal (2016)

80. Stéphane Louryan, Les preuves embryologiques de l’évolution (2016) 81. Michel Hambersin, Institutions culturelles et Nouvelles technologies.

L’exprérience du spéctacle vivant (2016)

82. Baudouin Decharneux, Socrate l’Athénien ou de l’invention du religieux (2016)

83.

84.

85.

86.

Hervé Hasquin, Inscrire la laïcité dans la Constitution belge ? (2016) Théophile Godefraind, Hominisation et transhumanisme (2016) Firouzeh Navahandi, Être femme en Iran. Quelle émancipation ? (2016) Philippe de Woot, Maîtriser le progrès économique et technique.

La force des choses et la responsabilité des hommes(2016)

87. Luc Chefneux, Pourquoi l’innovation ? Quels défis pour l’Europe ?

(2016)

88. Hugues Bersini, Big Brother is driving you (2016) 89. Xavier Dieux, L’Empire des choses. Liberté - Complexité - Responsabilité.

(2017)

90. Anne Richter, Les écrivains fantastiques féminins et la métamorphose (2017)

91.

Monique Mund-Dopchie, L’Atlantide de Platon. Histoire vraie ou préfiguration de l’Utopie de Thomas More ? (2017)

92. Lucien François, Le probleme de l’existence de Dieu. Et autres sources de conflits de valeurs (2017)

93. Francis Delpérée, L’état Belgique (2017)

Collection “Mémoires” Les Minorités, un défi pour les États. Actes de colloque (2012) L’idéologie du progrès dans la tourmente du postmodernisme.

Actes de colloque (2012) Denis Diagre, Le Jardin botanique de Bruxelles (1826–1912). Reflet de la Belgique, enfant de l’Afrique (2012) Musique et sciences de l’esprit. Actes de colloque (2012) Catherine Jacques, Les féministes belges et les luttes pour l’égalité politique et économique (1914-1968) (2013) Athéisme voilé/dévoilé aux temps modernes. Actes de colloque (2013) Stéphanie Claisse, Du Soldat Inconnu aux monuments commémoratifs belges de la Guerre 14-18 (2013) Georges Bernier, Darwin, un pionnier de la physiologie végétale.

L’apport de son fils Francis (2013) Jacques Reisse, Alfred Russel Wallace, plus darwiniste que Darwin mais politiquement moins correct (2013) La démocratie, enrayée ? Actes de colloque (2013) Catherine Thomas, Le visage humain de l’administration. Les grands commis du gouvernement central des Pays-Bas espagnols (1598-1700) (2014) Francis Robaszynski, Francis Amédro, Christian Devalque et Bertrand Matrion, Le Turonien des massifs d’Uchaux et de la Cèze (2014) Pierre Verhas, L’histoire de l’Observatoire royal de Belgique (2014) L’Homme, un animal comme un autre ? Actes de colloque édités par Jacques Reisse et Marc Richelle (2014) La bataille de Charleroi, 100 ans après. Actes de colloque (2014)

Pierre Assenmaker, De la victoire au pouvoir. Développement et manifestations de l’idéologie impératoriale à l’époque de Marius et de Sylla (2014) De Mons vers le Nouveau Monde. Lettres de Jean-Charles Houzeau en Jamaïque (1868-1876), Hossam Elkhadem et Marie-Thérèse Isaac (ed.) (2015) Le Quatrième partage de la Pologne. Actes de colloque (2015) Frédéric Boulvain et Jean-Louis Pingot, Genèse du sous-sol de la Wallonie (2015, 2e éd. revue et augmentée) La liberté d’expression. Menacée ou menaçante ? Actes de colloque (2015) Robert Wangermée et Valérie Dufour (dir.), Modernité musicale au XXe siécle et musicologie critique. Hommage à Célestin Deliège.

Actes de colloque (2015) Jean-Louis Migeot, Des chiffres et des notes. Mathématique et solfège, physique et musique : une introduction (2015) Hugues Bersini, Quand l’informatique réinvente la sociologie (2015) Jean-Louis Kupper, Notger de Liège (972-1008) (2016) émile Biémont, Le règne du temps : des cadrans solaires aux horloges atomiques (2016) L’évaluation de la recherche en question(s). Actes de colloque (2016) Jean-Charles Speeckaert, Dominique de Lesseps. Un diplomate français à Bruxelles au temps du renversement des alliances (17521765) (2016) Marc Groenen , L’art des grottes ornées du Paléolithique supérieur (2016) Stéphanie Claisse, Monuments aux morts... et aux survivants belges de la Guerre 14-18 (2016) Charleroi 1666-2016. 350 ans d’histoire des hommes, des techniques et des idées. Actes de colloque (2016)

Fig. 1 — La sculpture de verre devant le siège de AGC à Louvain-la-Neuve ; p : 2010, r : 2011-2014 (01/577).

Fig. 2 — L’efficience et la pérennité d’une construction en fonction des progrès de la connaissance.

Fig. 3 — Éclairage naturel journalier en Lux à Uccle (Bruxelles) pour des surfaces verticales nord, est, sud, ouest et le plan horizontal (avec un maximum de 90 000 Lux à midi sur l’horizontale au solstice d’été).

Fig. 4 — Éclairage naturel journalier en Lux à Uccle (Bruxelles) pour des surfaces verticales nord-est, sudest, sud-ouest, nord-ouest (avec un maximum de 90 000 Lux au zénith, le 21 juin à 12h00).

Fig. 5 — Siège social de la CNP/NPM, Gerpinnes ; p : 1994, r : 1995-1996, (01/320). Photographie janvier 2016.

Fig. 6 — Hall de production de panneaux photovoltaïques, Dison ; p : 2011 (01/592).

Fig. 7 — Insolation annuelle moyenne en Belgique (100 % = 1 100 kWh/m² an).

Fig. 8 — Lujiazhi Cultural Creativity Garden Zhoushan. Cultural coffee shop et sa verrière photovoltaïque, Zhoushan, Chine ; p : 2019, r : 2015-2016 (01/594).

Fig. 9 — Insolation annuelle moyenne à Zhoushan, Chine (100 % = 2 100 kWh/m² an).

Fig. 10 — Verrière photovoltaïque, caserne des pompiers, Houten, Pays-Bas ; p : 1998, r : 1999-2000 (01/373).

Fig. 11 — Les 2 200 dessins d’enfants dans la caserne.

Fig. 12 — EUROPA, siège du Conseil de l’Union européenne, Bruxelles ; p : 2005–2008, r : 2008–2016 (01/494).

Fig. 13 — EuroSpace Centre, Libin-Transinne ; p : 2006, r : 2007-2008 (01/518).

Fig. 14 — Façade photovoltaïque du bâtiment des sciences appliquées de l’Université libre de Bruxelles ; p : 2009, r : 2017 – 2018 (01/570).

Fig. 15 — Coupe perspective transversale.

Fig. 16 — La girouette d’Olivier Strebelle sur l’immeuble de bureaux pour Eric Boulanger, Waterloo ; p : 1998, r : 1989-1990 (01/200).

Fig. 17 — La salle de réunion et sa verrière de toiture sous la girouette.

Fig. 18 — L’oculus au plafond du hall d’accueil, sous la salle de réunion.

Fig. 19 — Les miroirs dans les ébrasements de fenêtres des bureaux de Samyn et Associés, Uccle ; p : 1992, r : 1993 (01/265).

Fig. 20 — Les miroirs dans les ébrasements de fenêtres et sur les étagères à lumière, EUROPA ; p : 2004, r : 2008 à 2016 (01/494).

Fig. 21 — Les étagères à lumière pour l’immeuble « Cristal », Bruxelles ; p : 1992, r : 1996-1998 (01/260).

Fig. 22 — Détail des caillebotis.

Fig. 23 — Les étagères à lumière au siège des entreprises Jan De Nul, Aalst ; p : 2000, r : 2001-2002 (01/401).

Fig. 24 — Les réflecteurs anidoliques pour le siège de la Caisse Congés du Bâtiment, Bruxelles ; p : 1997 (01/351).

Fig. 25 — Illustration de l’efficacité des réflecteurs de lumière naturelle.

Fig. 26 — Les grands pans semiréfléchissants forment des réflecteurs de lumière verticaux pour cet immeuble de bureaux, Bruxelles ; p : 1999 (01/381).

Fig. 27 — Capteurs de lumière en toiture pour la Fondation Polaire Internationale, Toronto, Canada ; p : 2004 (01/477).

Fig. 28 — Coupe transversale.

Fig. 29 â&#x20AC;&#x201D; Conduits de lumière dans les colonnes en bois.

Fig. 30 — Coupe perspective illustrant les jeux de miroirs de la Maison de l’Histoire européenne, Bruxelles ; p : 2010 (01/573).

Fig. 31 — Les canons de lumière naturelle éclairant les salles obscures.

Fig. 32 — Une résille structurelle en bois porte la toiture et diffuse la lumière naturelle dans le crematorium, Aalst ; p : 2010 (01/583).

Fig. 33 — Un héliostat avec miroir elliptique éclaire le cœur du crématorium.

Fig. 34 — Les miroirs en toiture annoncent de loin le crématorium.

Fig. 35 — 232 héliostats au Guggenheim à Helsinki, Finlande ; p : 2014 (01/619).

Fig. 36 — Maquette.

Fig. 37 — L’héliostat rectangulaire dans la cour centrale de la caserne des pompiers à Charleroi ; p : 2014, r : 2015-2016 (01/569).

Fig. 38 â&#x20AC;&#x201D; La cour de la ferme de Stassart, Uccle (01/265).

Fig. 39 â&#x20AC;&#x201D; Les patios de la caserne des pompiers de Charleroi (01/569).

Fig. 40 — M&G Ricerche, Venafro, Italie ; p : 1989, r : 1990-1991 (01/222).

Fig. 42 — Brussimmo, Bruxelles ; p : 1991, r : 1992-1993 (01/225).

Fig. 41 — OCAS, Zelzate ; p : 1981, r : 1990-1991 (01/223).

Fig. 43 — Auditoire de première candidature médecine, Hôpital Erasme, Bruxelles ; p : 1992, r : 1993 (01/270).

Fig. 44 — Éditions Dupuis, Marcinelle ; p : 1993, r : 1994-1995 (01/286).

Fig. 45 — La Grande Aula, Louvain-laNeuve ; p : 1999, r : 2000-2001 (01/291).

Fig. 46 — Le parterre aveugle sous les KW électriques.

Fig. 47 — Balcons et double peau. Villas de Ganshoren, Bruxelles ; p : 2016 (01/633).

Fig. 48 — Les vantelles de verre clair, avenue Marnix, Bruxelles ; p : 2006, r : 2007-2009 (01/489).

Fig. 49 — Les vantelles sérigraphiées assurent la diffusion de la lumière dans les bureaux du siège de ENI (Ente Nationale Idrocarburi), Rome, Italie ; p : 1998 (01/375).

Fig. 50 — Les gigantesques vantelles protègent les façades est et ouest du soleil.

Fig. 51 — Le siège social de AGC Glass Europe, Louvain-la-Neuve ; p : 2010, r : 2011-2014 (01/577).

Fig. 52 — Les vantelles nord et sud, est et ouest.

Fig. 53 — Vue intérieure.

Fig. 54 — Les vantelles du deuxième nouveau siège des entreprises Jan De Nul, Aalst ; p : 2015-2016, r : 2017-2018 (01/571).

Fig. 55 — Maison de la Culture de la Province de Namur ; p : 2015, r : 2017-2018 (01/628).

Fig. 56 — Les vantelles en acier laqué blanc.

Fig. 57 — Le patchwork de vieux châssis de chêne, EUROPA (01/494).

Fig. 58 — La « lanterne » en verre sérigraphié.

Fig. 59 — Le gris pur à 60 % de noir et la résille photovoltaïque du château « Groenhof », Malderen ; p : 1998, r : 1999-2000 (01/352).

Fig. 60 — Imposte en miroir et papier d’aluminium froissé tapissant les murs de l’annexe du château « Groenhof ».

Fig. 61 — Les « bacs » en verre au pied des verrières, KBC Verzekeringen, Leuven ; p : 2002 (01/433).

Fig. 62 — Les tubes à ailettes au pied de la verrière EUROPA (01/494).

Fig. 63 — Le Comptoir forestier à Marche-en-Famenne ; p : 1992, r : 1993-1994 (01/279).

Fig. 64 — Vue de nuit.

Fig. 65 — Vue intérieure.

Fig. 66 — La verrière en cylindre elliptique du Neanderthal Museum à Erkhrath-Mettmann, Allemagne ; p : 1993 (01/290).

Fig. 67 — La verrière en chaînette du restaurant pour Petrofina, rue Guimard, Bruxelles ; p : 1994, r : 1995-1996 (01/313).

Fig. 68 — La verrière conique du Musée du Verre à Lommel, extérieur ; p : 2004, r : 2005-2006 (01/469).

Fig. 69 — Les escaliers.

Fig. 70 — L’atelier de Erik Salvesen à Ekenäs-Tammisaari, Finlande ; p : 2009, r : en attente. (01/561).

Fig. 71 — L’espace intérieur de M&G Ricerche (voir aussi Fig. 40), (01/222).

Fig. 72 — La station de métro Bruxelles-Erasme ; p : 1995, r : 2001-2003 (01/283).

Fig. 73 — Le film d’ETFE sur filin para-aramide au centre de recherches Solvay à Neder-over-Heembeek ; p : 1987 (01/190).

Fig. 74 — La gare Vesuvio Est près de Naples, Italie ; p : 2008, r : en cours d’étude (01/552).

Fig. 75 — Les Burundais invités à « tisser » leur centre culturel à N’Goziv; p : 2009, r : inconnu (01/567).

Fig. 76 — La grande tente ETFE para-aramide à Zhoushan ; p : 2010, r : en cours d’étude (01/574).

Fig. 77 — Les écrans en métal déployé à Houten, Pays-Bas ; p : 1998, r : 1999 (01/363).

Fig. 78 — Les terrasses « cubes » de 3 m de côté, rue des Minimes à Bruxelles ; p : 2001-2007, r : 2008-2011 (01/421).

Fig. 79 — Les tôles perforées portant les escaliers de secours dans la « lanterne » EUROPA (01/494).

Fig. 80 — Les colonnes en tôle perforée sur les cuves du chai de Château Cheval Blanc à Saint-Émilion, France ; p : 2008 (01/542).

Fig. 81 — La tour d’exercice de la caserne des pompiers à Charleroi (01/569).

Fig. 82 — Tour Dexia, place Rogier, Bruxelles ; p : 2002, r : 2003-2006 (01/301).