Translucent Craft by Lulu Le Li

THE TRANSLUCENT CRAFT The combination of paper and wax

Acknowledgements I should like to thank Eva MacNamra, my thesis tutor, for her supervision and steady advices on producing this thesis. Dr. Peg Rawes and Mark Smout, the course coordinators, Izaskun Chinchilla and Carlos Jimenez, my design unit tutors, for their helpful advices. Mohit Mamudi and my mum for their support and proof reading.

THE TRANSLUCENT CRAFT The combination of paper and wax

Lulu Le Li Thesis April 2013

CONTENT 1.0 INTRODUCTION 2.0 CONTEXT

2.1 History of Hutong and courtyard houses and their decline in modern era 2.2 Hutong architecture (courtyard houses) 2.3 The decline of traditional craftsmanship 2.4 Modern technologies and reinterpretation of traditional materials

3.0 DESIGN PROPOSAL 4.0 THE RETURN OF PAPER - Role of paper in Chinese culture and architecture

4.1 The historical use of paper in Chinese culture and architecture 4.2 The translucent threshold in Chinese philosophy 4.3 The application of paper in architecture

5.0 INTRODUCTION TO WAX - A combination of paper and wax 6.0 PROTOTYPE PAPER-WAX TILES

6.1 Paper wax tile technical requirements and ideal properties 6.2 Site climate condition 6.3 The choice of wax 6.4 Paper-wax tile early samples 6.5 Selected paper wax tiles 6.6 Construction of test tiles 6.7 Simulation and evaluation Test 1: Structural performance Test 2: Thermal performance Test 3: Light transmission performance Test 4: Melting performance 6.8 Technical summary and analysis

7.0 CONCLUSION AND APPLICATION BIBLIOGRAPHY LIST OF ILLUSTRATIONS

1.0 INTRODUCTION

China is experiencing an exponential growth and modernization. High technology and digital means are often incorporated in the new urban China’s construction boom. The result very often has been “technification” of urban environment with large scale architectural developments which have erased local cultural richness, turning cities into standardised modern mega-city. The rapid transformation of major cities like Beijing means the traditional vernacular building fabric such as Hutong (narrow lanes lined with traditional courtyard houses) has been either demolished for redevelopment or coexists uneasily alongside new generic steel and glass towers in a seemingly chaotic agglomeration. A possible reaction to this could be a romantic crusade to rebuild the past. The aim of this study, on the contrary, is to find new links between cosy cultural traditions and contemporary technical capacities; looking for a practical hybrid of past and present for the future. More specifically, this essay proposes that the beauty and delicacy of traditional paper craft, Chinese lattice art and wax could be reinvented and developed with the help of contemporary digital fabrication, to create temporary architectural elements in harmony with culture and climatic condition. This could then be used to regenerate the traditional architecture – albeit on a smaller scale and less permanent - to counter-balance the permanent modern architectures currently void of any cultural awareness. Objectives: 1. To offer background study of the Chinese cultural traditions in relation to architecture, the issue of modern architecture and the potentials of contemporary digital fabrication. 2. To initiate a technical study in reintroduction of paper as architecture material and test how paper can be used together with wax to create temporary architectural elements fit for the culture and weather, through a combination of craftsmanship and contemporary fabrication. Structure: The first part of this paper reviews the general cultural traditions of Hutong architecture in relation to the concepts of craftsmanship, nature connections and boundary conditions. Secondly, examples of brutal modern architecture will be used to critique the current building environment in Beijing, which is not respecting the culture and context but is primarily visually driven, striving for challenging structures and innovative appearances. Thirdly, some related modern technologies will be briefly introduced in relation to digital fabrication and how they could be used to design cosy digital architectures that have cultural awareness. I will then study the role of paper craft in Chinese culture and architecture in relation to the idea of temporary and translucent threshold, followed by an outline of a project for which the temporary and cultural based architecture and translucent threshold are being studied. In general, it is in relation to a disbursed architecture school design as an insertion to the existing Hutong fabric. The school architecture has a 7-year life cycle and will be used as an overlaid organic system to evolve together with the otherwise dying Hutong culture. Therefore, the tension between the students and locals, the school program and local activities, school developments and Hutong modernization will be addressed through the design of the threshold and boundary conditions.

In the second section, I will first introduce wax as a potential material to work with paper in order to develop and regenerate the paper craft to form temporary walls with tiles or screen units. I will give a basic scientific study of the production, processing, properties and applications of different waxes, followed by the properties necessary in a wax for it to be used as a structure material, and a series of sample tests to find the appropriate wax and a range of paper insertions as reinforcement and light filter. I will then attempt, through a series of experiments, to evaluate: Paper-wax tile: 1. The structural support, use of paper and thickness of wax to withstand the strong wind-loads in Beijing, China 2. The thermal performance of paper-wax tile, its potential as a thermal storage and the thickness necessary to match the U-value of a wall or single glazed window as defined by the Building Regulation in China 3. The light transmittance properties and the quality of shadows for different types of paper-wax tiles 4. The melting point and melting effect of the paper-wax tiles, how that affect the structural stability and potential for ventilation The results of the experiments will be analysed in comparison to the hypothesis, leading to the â&#x20AC;&#x153;idealâ&#x20AC;? paper-wax tile, with the right thickness of wax and paper insertions. The thesis will conclude with a discussion of the results in relation to the design of paper-wax architecture with advantage and disadvantages, possible other applications and improvements, and a re-evaluation of the paper-wax architecture design as a new link between Chinese cultural traditions and contemporary technical capacities.

2.0 CONTEXT

2.1 History of Hutong and courtyard houses and their decline in modern era

Fig. 1: The city plan

Fig. 4: A bird’s-eye view of the Hutong and courtyard houses

Fig. 2: The district plan

With the 1949 communist revolution, the social and cultural values of China were cataclysmically shaken and altered to such an extent that even the long-practiced building methods (Hutong and courtyard houses) that had defined urban living in Beijing were viewed as outdated and no longer relevant. Chinese communists sought to create a fresh, new socialist utopia, and any cultural icon (including Hutong and courtyard houses) of China’s past became suspect. In a race to build up China’s industrial capacity, many Siheyuans (courtyard houses) were destroyed. Since the 1980s, the Chinese government has been implementing a housing relocation plan called the “Weigai” system (Old and Dilapidated Housing Redevelopment). The goal is to transform old Hutongs into new high-density residential neighbourhoods with modern utilities, but it has led to a mass destruction of Beijing’s cultural assets.

Fig. 3: The courtyard house plan Historical Street - Hutong - Courtyard house system and hierarchy diagram

Many Siheyuans have also been demolished for the city’s concentric circled “ring-road” highway system, developed in the 1990s. The 2008 Olympics Games put even more pressure on these unique aspects of China’s cultural heritage, and Beijing further accelerated the destruction of courtyard houses to make way for sports venues and infrastructure for the games. Between 1990 and 1998, 45.2 million square feet of Siheyuans were demolished, to raise the total destruction since 1950s to 150.7 million square feet. 11

Here is an map of central Bejing with historical areas (highlighted in red) still in place by 2003.

Fig. 5: Map of historical areas by 2003

Examples of some of the modern buildings in central Beijing (2012).

Fig. 7: Beijing national theatre

Fig. 6: Beijing city skyline

Fig. 8: Television cultural center

Fig. 9: CCTV Headquarters

2.2 Hutong architecture (courtyard houses) Confucianism, which respects individualism and emphasizes self-discipline, had tremendous influences on Siheyuan design. Siheyuan was enclosed by thick brick walls with usually only one main entrance located near the southeast corner of the building. Isolation from the outside environment was supposed to reinforce the sense of individualism and selfconsciousness. It created a tranquil environment and a place for meditation. Inside, the house was divided into different buildings. This symbolic division idealized individualism, suggesting a greater social structure around these discrete elements. It was also meant to provide privacy and more harmonized relationships for the residents. The ancient Chinese believed that humanity should exist in harmony with nature. In Siheyuan houses, the connection with nature is expressed through the centrally located courtyard. It maintains the well-being of the inhabitants by bringing in natural light and providing ventilation to the building. The open courtyard, semi-open corridor space, thin walls, large rice paper windows, stone floor tile in the rooms blurred the boundary between interior and exterior, allowing people to fully experience the nature, enjoy the sun, feel the temperature, listen to the rain, smell the flowers.

10 11 12 ----------------13 14

Fig. 10: Courtyard space in the spring rain Fig. 11: Courtyard space in the sun Fig. 12: Courtyard space covered with snow Fig. 13: Rain falls on the Hutong architecture Fig. 14: Torned rice paper window

5 4 3 2 6

1. Main gate 2. Screen wall 3. Main courtyard 4. Eastern wing room 5. Principal room 6. Western wing room 7. Short-cut corridor 8. Reversibly-set room

7 1 8

Fig. 15: The typical layout of a medium Courtyard House

Fig. 16: The typical structure of a traditional courtyard house

2.3 The decline of traditional craftsmanship Case studies and samples of traditional techniques, beautiful crafts and Chinese mythology in Hutong Architecture, Beijing.

Dou Gong A unique interlocking wooden bracketing system. Historical use: The pieces are fit together by joinery alone without glue or nail. This system is earthquake resistant and helped ancient buildings to survive for a long time. Modern use: Rarely in modern building. Not efficient enough in terms of labour, time and cost.

Fig. 17: The typical structure of a Dou Gong

Brick Sculpture Historical use: Bricks carved with patterns in relief were used for decorative purposes on the exterior of old houses of officials and the rich. Modern use: Sculptures rarely done in bricks but use clays or plasters instead as itâ&#x20AC;&#x2122;s cheaper and easier done by machines

Fig. 18: Example of brick sculpture

Fig. 19: Brick sculpture motif

Latticework motifs on Doors and Windows Historical use: The latticework motif of diverse and elaborate designs that characterizes the traditional doors and windows has exerted a far-reaching influence on Chinese architectural ornamentation. Modern use: Rarely used in modern architecture but in expensive hand crafted wooden furniture.

Fig. 20 & 21: Example of latticework

Paper windows Historical use: For centuries the Chinese used paper covered wooden lattice grilles in their windows. The lattice was often painted in black or dark red lacquer and decorated with gilt flowers and ornament. Modern use: Rarely used today as glass has become the material of choice in windows, for better lighting and insulation.

Fig. 22: Example of paper window

2.4 Modern technology and reinterpretation of traditional materials With the modern technology, a lot of designs which were traditionally crafted by hand can be reproduced by a more time and labour efficient digital fabrication, such as laser cutting, 3D printing, CNC milling and with the help of robot arms, etc. Samples bellow show how traditional design and materials can be reinterpreted and developed with modern technology.

Intricate window design achieved by laser cutting multiple layers of cards

CNC router with multiple axis can be used to create precise wood relief, patterns and even columns Fig: 23 24 ------------25 26 27 ------------28 29 30

Non standard material such as wax can also be sculpted through CNC milling

3.0 DESIGN PROPOSAL

After in depth study of the traditional Hutong culture and Chinaâ&#x20AC;&#x2122;s modern architecture, I believe that the mass destruction of Hutong architecture has put Hutongâ&#x20AC;&#x2122;s dense social network and intimate culture under serious threat and has left the local people feeling insecure. I propose to design a school of architecture disbursed within an existing Hutong fabric. The school will have a 7-year life cycle - with informal learning environment - as an organic system to evolve together with the otherwise dying Hutong culture. To preserve the cultural traditions, I believe first we need to bring back the meaning and value of the culture. My project critiques the modern singular educational system, which is study based, result oriented and divorced from the real world and traditions. School buildings are quite often enclosed reinforced concrete blocks, which look similar to hospitals or office buildings. In my view architecture design should engage with everyday life and not divorced from the past, just like Bauhaus philosophy. Therefore, I want to challenge the present school system and design a temporary school environment that connects with tradition and interfaces with the city to make continuity and articulation. I believe Hutong offers the most intimate and organic system for learning and experiencing the architecture and culture. The shared space, porous structure, the different spatial and acoustic quality also offers a continuation of space for thinking and imagination. The project will also try to address the tension between the students and locals, the school program and local activities, school developments and Hutong modernization, through the study of translucent learning environment, dealing with threshold, concealment, implication and relationship between private and public.

Fig. 31 & 32: Perspective image of the school library design

Fig. 33: Composite drawing of the school workshop design

Fig. 34: Collage drawing showing the integration of Hutong and school activities

4.0 THE RETURN OF PAPER

- Role of paper in Chinese culture and architecture

4.1 The historical use of paper in Chinese culture and architecture Paper was Invented China. The earliest form of paper appeared in the Western Han Dynasty (206BC-23AD), but the paper was generally very thick, coarse and uneven in texture, made from pounded and disintegrated hemp fibre. In the Eastern Han Dynasty (25-220AD), a court official named Cai Lun invented a new kind of paper (about 105AD), which not only greatly improved the papermaking technique, but also made it possible to use a variety of materials. Paper then became relatively cheap, light, thin, durable and more suitable for brush writing. Apart from the obvious use of paper in writing and painting, paper was also widely used in traditional Chinese culture. People burned paper offerings for gods, ghosts, and ancestors. Even today there are paper objects for religious occasions, for festivals, for ceremonial events, both in public worship and private devotion. Unlike the paper we use today, traditional Chinese paper was very thin and translucent, therefore it was also widely used in room dividers, lamp-shades, screens and window coverings. Plain white sorghum paper was mostly used for the window coverings, as it is strong enough to sustain the strong winds in Northern China. Sometimes paper with printed decoration or calligraphy was also used. The paper breaks or turns yellow after a year of weathering and were normally replaced on the Chinese New Year with fresh white paper as a ritual of celebrating a fresh start.

35 36 37 38 ---------------39

Fig. 35 Fig. 36 Fig. 37 Fig. 38 Fig. 39

The ritual of replacing window paper every new year Traditional paper cut Paper objects for burning at religious ceremonies Paper lanterns for good wishes Rice paper for painting and calligraphy

4.2 The translucent threshold in Chinese philosophy For centuries the Chinese used paper covered wooden lattice grilles in their windows. The lattice was often painted in black or dark red lacquer and decorated with gilt flowers and ornament. During the day, as the paper was translucent it was the shadow of the lattice design and the silhouettes of the garden which were the window feature instead of the actual views of the outside world. At night, when the interior is lit and occupied, the shadows cast by the occupying object fall onto the paper and are captured and expressed on the exterior of the paper window. The paper window therefore act as a translucent threshold, allows for a specific expression of the occupation into the urban realm outside, different from the action of both transparent and opaque thresholds. The concept of translucent threshold was derived from the Buddhist philosophy “意境(Yi Jing)” which is a status of harmony between reality and imagination, manmade and nature, yin and yang with a timeless quality. These concepts also play a large part in Chinese life. People who are aesthetically perceptive look for more than durability and practicality. Such a person would find beauty in the moonlit shadow of a pine branch on a paper window at night.

Fig. 40 & 41 Translucent threshold created by rice paper windows and screens

4.3 The application of paper in architecture Despite its fragility and lack of thermal insulation, paper is widely used and challenged as a building material in modern architecture for itâ&#x20AC;&#x2122;s unique translucent and delicate properties and great potentials. Examples of the applications of paper in architecture. 42 43 -------44 ---- 46 45

Fig. 42 Paper card house Fig. 43 Tracing paper installation Fig. 44 Card pavilion Fig. 45 Paper brick house Fig. 46 Paper chandeliers

5.0 INTRODUCTION TO WAX

- A combination of paper and wax

Although translucent rice paper lattice window works just fine visually to diffuse natural light entering the room, creating a very serene and peaceful atmosphere, when it comes to the practicality of paper window, its weakness in durability, structural stability, water resistance and thermal insulation becomes quite apparent. In order to develop and regenerate the paper craft to form structural elements of some rigidity while keeping the temporary and translucent quality of paper, combining paper with wax becomes an appropriate option as wax has different properties under different circumstances while one of its main properties is translucency. Different to the translucent threshold created by paper, wax not only diffuses the light that passes through it, but also appears to capture it, contain it, and glow. The additional ability of wax to store heat and resist water penetration gives the wax threshold a very specific character. With additional paper insertions as light filter and structure reinforcement, a more interesting light and shadow effect could be achieved together with better structural and thermal performances than with either of them alone.

Sources of wax There are six main natural sources of wax.

â&#x20AC;˘

wax produced by insects

This is found mainly as beeswax, although several other insects also produce a waxy secretion but in very small quantities. Beeswax, after washing and filtering, is commonly use in production of candles, cosmetics, confectionery, pharmaceuticals, etc. As a material, beeswax is soft and pliable, with a melting point of approx. 40Â°C.

Fig. 47 & 48 Images of beeswax

•

wax produced by plants

Wax appears mainly as an excretion on the leaves, stems or fruit of plants. In some cases the secretion is abundant and is of great importance to the plant. Carnauba wax: This hard yellow-brown wax comes from the Carnauba palm tree and is found only in the north east of Brazil. Different ages of plant give waxes of different qualities, but all are brittle in nature. Candelilla wax: Candelilla is obtained from the coating of the “wax slipper plant” Euphorbia Cerifera. In its refined form, the wax is used extensively in the Cosmetic Industry.

Fig. 49 Image of Carnauba wax Fig. 50 Image of Candelilla wax

â&#x20AC;˘

wax produced by animals

There are 2 main types of animal wax, Woolwax and Spermaceti wax. Woolwax: is produced on the wool of sheep, as a waterproof coating and insulation payer. It is collected by boiling the wool in water and skimming off the crude wax. It has limited uses due to the small amount of wax available per sheep. Spermaceti wax: is found in the head cavity of the sperm whale as a liquid, which can be distilled off and allowed to solidify at room temperature. It also has limited uses due to its very low melting point of approx. 20Â°C and availability problems.

Fig. 51 Image of Woolwax Fig. 52 Image of Spermaceti wax

â&#x20AC;˘

wax found in fossils

Fossil waxes are waxes associated with fossil remains, which have not been bituminised, i.e. converted to hydrocarbons by geological change. Montan wax: Crude Montan Wax is found in certain types of lignite or brown coal deposits which have been formed over millions of years. The wax is always dark brown in colour with high melting point of approx. 55Â°C. It is used mainly in the rubber and road construction industries. Peat wax: Peat wax is the part of the bitumen leftover. The wax is a dark waxy substance similar to the coal derived Montan wax and therefore has similar properties and uses.

Fig. 53 Image of Montan wax Fig. 54 Image of Peat wax

•

wax derived from curde oil

The wax derived from crude oil forms the bulk of wax widely used in contemporary society for two reasons. Firstly, a large range of waxes with varying properties can be produced easily; and secondly, they are far cheaper than other waxes because they are direct by-products of the petroleum industry. The classifications of refined Petroleum waxes are:

Fig. 53 Image of Paraffin wax group

Paraffin wax group: Paraffin Waxes are solid hydrocarbons of high quality, fully refined to become white, odourless and tasteless with oil content generally less than 0.5%. They are available in a wide range of melting points from 42/44°C to 65/68°C. Paraffin has a macrocrystalline structure which means that they have a degree of brittleness, compared to the microcrystalline waxes. The advantages of Paraffin Wax include its excellent protection and barrier properties preventing water penetration and making an ideal coating in the cardboard and paper industries.

Microcrystalline wax group: Microcrystalline wax is an oil derived product obtained from dewaxing lube oil in the refinery process. It is made up of saturated hydrocarbons possessing a fine-grained crystal structure which renders them more flexible than paraffin waxes with diverse applications. It is characterised by high molecular weight, viscosity, melting point and a more opaque appearance. Colours range from white through yellow to dark brown. Melting points range from 60째C to 80째C. The higher melting grades (75째C+) increase tensile strength and rigidity, improving stability and scuff resistance.

Fig. 53 The macro-crystalline structure and micro-crystalline structure of wax

6.0 PROTOTYPE PAPER-WAX TILES

6.1 Paper wax tile technical requirements and ideal properties In order to design a temporary wall with paper-wax tiles, certain physical properties are required to withstand climatic conditions and respond to the changing weather conditions - such as strong wind in winter and hot summer in Beijing. It should also give the required luminosity within the space defined by the enclosed walls, and match the current Chinese Building Regulations. The ideal properties of the paper-wax tiles would be: a. Structural performance: The ability to withstand the maximum wind-load in relation to site exposure, based on calculations from Chinese Building Regulations. b. Thermal performance: Meeting the current regulations concerning insulation levels and match the U-value of a wall or single glazed window as defined by the Chinese Building Regulations. c. Light transmission performance: The appropriate thickness to allow for the casting and revealing of shadows of the occupants onto its exterior surface. The amount of daylight passing through the wall is also of prime importance allowing for a decent lighting quality in the room without artificial light. d. Melting performance: The melting point of the tiles should be between 40째C-45째C with gradual melting process, allowing changes in its structural with potential to leave just the paper insertions in the wall structure at the peak of the summer, to form a naturally ventilated space.

6.2 Site climate condition Beijing has a rather dry, monsoon-influenced humid continental climate in summer with temperatures exceeding 40°C, and characterized by cold, windy and dry winters when temperature can dip to -20°C due to the Siberian air masses that move southward across the Mongolian Plateau. Spring can bear witness to sandstorms blowing in from the Mongolian steppe, accompanied by rapidly warming, but generally dry conditions. Autumn, like spring, sees little rain, is normally cool and pleasant but short. January tends to be the coldest month and July is the warmest.

Table of statistics for Beijing climate for each month of the year:

Average temperature (°C) Maximum temperature (°C) Minimum temperature (°C) Precipitation (mm) Average wind speed (m/s)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -3.7 -0.7 5.8 14.2 19.9 24.4 27.2 24.8 20.0 13.1 4.6 -1.5

12.9 19.8 26.4 31.1 36.8 39.8 42.9 38.3 34.4 29.3 22.0 19.5

-22.8 -17.6 -12.5 -2.2 4.6 11.8 18.6 13.4 5.3 -1.4 -10.6 -18.0 2.7 4.9 3.3 21.2 34.2 78.1 185.2 159.7 45.5 21.8 7.4 2.8

2.6 2.8 3.1 3.2 2.8 2.4 2.0 1.8 2.0 2.1 2.4 2.5

6.3 The choice of Wax From the material specification and site condition outlined above, it can be seen that the majority of waxes will be unsuitable as a tile/cladding material. Beeswax gives a beautifully warm light transmission quality and have the ideal low melting point, but doesn’t have the necessary flexibility or structural capability. Plant wax is generally brittle due to their macro-crystalline structure and therefore liable to crack under tensile pressure (such as wind loading). Fossil wax melting point is too high for the site and it’s macro-crystalline structure and dark brown colour reducing light transmission make it unsuitable. Earth wax has a very low melting point and therefore unsuitable as wall tile material. Waxes derived from crude oil have the best properties for use in wall tiles such as the range of melting points, water resistance, tensile strength and rigidity, as well as low cost. They are also the most widely available of all waxes. Paraffin wax is better than Micro-crystalline wax for its ideal melting point and translucent qualities, even though a weaker crystalline structure.

Chosen wax type: Low melting fully refined Paraffin wax PHC No. 4146 Melting point (ASTM D938)

42 - 46°C

Penetration, needle @ 25°C (ASTM D1321)

80 – 120 (mm x 0.1)

Oil Content (ASTM D721)

3.5% Max.

F & DA Approved (172.886)

Pass

Colour

Pale yellow

6.4 Paper-wax tile early samples In order to establish a good understanding of the paper-wax as a tiling material and itâ&#x20AC;&#x2122;s properties and potential, a number of small paper-wax samples are made with different types of paper reinforcement, different positions for the paper insertions and different wax thicknesses as an initial experiment to find the ideal quality paper-wax. The wax and paper samples will then be analysed in terms of their structural ability and light transmission performance. The selected top three paper-wax types will be made to 1:1 scale tiles with different thickness for the proposed structure, light transmission, insulation and melting test.

Type 1 Rustic ice-ray patterned paper cut inserted in the middle of the cast wax. Materials: Paper cut (120gsm) Wax Potential connection to frame: Clamp Thickness: 8mm

Type 2 Various width of shredded paper strips are waved in between the cotton thread net, which is stitched to the wax mould. Materials: Paper strips Wax Cotton thread Potential connection to frame: Tie to the frame with threads Thickness: 10mm

Type 3 Rustic ice-ray patterned paper cut inserted in the middle of the cast wax. Materials: Paper cut with tracing paper Wax Potential connection to frame: Clamp Thickness: 3mm

Type 4 Various shredded paper pieces are placed in between the diagonally stitched cotton threads. Materials: Shredded paper pieces Cotton thread Wax Potential connection to frame: Tie to the frame with threads Thickness: 6mm

Type 5 Wax cast with moulded â&#x20AC;&#x153;landscapesâ&#x20AC;? to create changing thickness for a varying light transmission performance. Losely stitched cotton thread are used for reinforcement. Materials: Thick cardboard Wax Potential connection to frame: Tie to the frame with threads Thickness: varies

Type 6 Open top wax casting with honey-comb paper insertion. Materials: Honey comb paper Wax Potential connection to frame: Clamp Thickness: 10mm

Type 7 Capped wax casting with honey-comb paper insertion. Materials: Honey comb paper Wax Potential connection to frame: Clamp Thickness: 10mm

Type 8 Rustic ice-ray patterned paper cut inserted in the middle of the cast wax. Materials: Paper cut (120gsm) Wax Potential connection to frame: Clamp Thickness: 7mm

Type 9 Rustic ice-ray patterned paper is cut selectively as windows and placed at the top of the cast wax to control the position and amount of light transmission. Materials: Paper cut (120gsm) Wax Potential connection to frame: Clamp Thickness: 6mm

6.5 Selected paper wax tiles Three types of tiles are chosen and made into 1:2 tiles with frame based on the structure and light transmission performance of the early samples. Type 1: Rustic ice-ray patterned paper cut inserted in the middle of the cast wax. Materials: Paper cut (120gsm) Fully refined Paraffin wax Connection to frame: Clamped by wooden frame Thickness: 5mm- 12mm, bigger tiles with greater thickness Analysis: Great light transmission performance. The paper insertion becomes almost invisible when the thickness between the paper and wax surface is greater than 3mm. The patterns of the paper cut only reveals when it is lit from behind. Based on the result of the crack test, the tile is generally weak in both compressive and tensile strength therefore relatively easy to break by hand at 7mm thickness. The crack is generally straight, crisp and has no influence from the paper insertions. Therefore it is speculated that the paper reinforcement doesnâ&#x20AC;&#x2122;t contribute to the structural ability when the wax is above certain thickness.

Type 2: Wax casted with honey-comb paper insertion. The honey-comb paper is the same thickness as the wax tile. Materials: Honey-comb crafting paper Fully refined Paraffin wax Connection to frame: Clamped by wooden frame and brass clips Thickness: 12mm Analysis: The honey-comb paper insertion controls both the light transmission performance and the surface texture of the wax tiles. When wax is congealed, the open surface shrinks along the honey-comb paper edges to form un-even honey comb patterned surface. The bottom face has a flat surface with half revealed honey-comb paper insertion and gives a more pixelated shadow effect when lit from behind. This type of tile has strong compressive strength but weaker tensile strength, according to the crack test result at 10mm thickness and the structure performance of the honey-comb paper on itself. It is hard to break the tile into half along the short edge as the honey-comb paper insertion acts as a reinforcement to hold the wax together. But it is relatively easy to break the tile when the force is placed along the direction of the honey-comb paper pattern at 30 degree angle. Therefore, the crack appears to follow the edge of the pattern as it is the weak point of the structure reinforcement. 45

Type 3: Various width of shredded paper strips are waved in between the cotton thread net, which is stitched to the frame. The paper strips and cotton threads are acting together as light filter and reinforcement. Materials: Paper strips Fully refined Paraffin wax Cotton threads Potential connection to frame: Tie to the frame with threads Thickness: 10mm Analysis: The cotton thread net doesnâ&#x20AC;&#x2122;t affect the light transmission performance when the wax reaches certain thickness. The light transmission performance is largely dependent on the amount of the paper strips used as insertions. Since the paper strips are acting as structural reinforcement, it is therefore important to find the balance between the thickness, structural performance and light transmission performance. The tile is very hard to crack by hand at 10mm thickness, and even when it breaks into two parts, they are still closely connected by the inserted cotton threads. It is not clear from the shape of the crack how much the paper strips are contributing to the structural performance. But it is certain that the cotton threads are playing an important role in the tensile strength of the tile. Therefore it is speculated that this type of tile has very strong tensile strength but potentially weaker compressive strength. 46

6.6 Construction of test tiles In order to test and compare the properties of the paper wax tiles under a fair condition, sample tiles with different paper reinforcement are casted with the same wax to a specified thickness, using the same mould and frame material, to the same size. Based on earlier sample tests, the 1:1 tiles will be made to: Number of tile types: 3 types Tile size: 170mm x 200mm Choice of wax: Paraffin wax with melting point 42 - 46째C Use of paper: Snowdon Cartridge paper 150gsm, honeycomb craft paper, 90gsm shredded paper Frame material: MDF Thickness of tile: 3mm | 6mm | 9mm | 12mm | 15mm Total tile number: 15 x 2 sets = 30 tiles Process of casting tiles All the MDF frames and rustic ice-ray patterned paper cut are done by laser cutter.

Type 1 1:2 Section through mould, frame, paper reinforcement and wax @ 15mm thickness. The positioning of the paper cut within the wax was maintained at 3mm below the tile surface for all tile thicknesses, except for the 3mm thick tile where the paper cut is placed in the middle. Perfectly level and sealed paper and timber moulds with different depth are made, which are crucial for the success of the wax casting.

2 A precise quantity of melted wax is poured into the mould to make sure the wax surface is in level with the edge of the mould to reach the specified tile thickness, calculated based on the area needed to be covered and the thickness required.

1 MDF frame 2 Paper cut insertion 3 Level and sealed mould 4 Wax casting 5 Congealed paper wax tile 6 Mould removed

Type 2 1:2 Section through mould, frame, paper reinforcement and wax @ 15mm thickness. The positioning of the honey-comb paper within the wax was maintained for the tiles at different thickness. And the depth of the honey-comb paper is always the same as the depth of the frame. The honey-comb paper is cut to size, glued to the needed width and stretched inside the mould. Perfectly level and sealed paper and timber moulds with different depth are made.

2 The position of the honey-comb is sometimes adjusted right after the wax is poured in as the wax pouring action sometimes pushes the honey-comb paper to form an uneven pattern.

1 MDF frame 2 Honey comb paper insertion 3 Level and sealed mould 4 Wax casting 5 Congealed paper wax tile 6 Mould removed

Type 3 1:2 Section through mould, frame, paper reinforcement and wax @ 15mm thickness. The laser-cut holes in the frame made sure the cotton thread could be woven evenly within the frame. When stitching the thread through the frame, it is always one up and then one down to form an inter-locked net that firmly hold the frame and the paper strips together. The moulds are made perfectly level and are sealed with extra care to avoid leakage from holes in the frame. A precise quantity of melted wax is poured into the mould with slightly lower temperature which helps the wax to congeal quicker in the room temperature in case of leaks. 1

1 MDF frame with stitched threads 2 Inter-locked cotton threads 3 Level and sealed mould 4 Wax casting 5 Congealed paper wax tile 6 Mould removed

6.7 Simulation and evaluation Note: The aim of the following limited number of tests was merely to establish preliminary parameters to judge the possible performance and viability of various types of tiles. To reach statistically valid conclusions greater number of tests for each type of tile is necessary.

TEST 1: STRUCTURAL PERFORMANCE Both wax and paper have minimal structural strength of their own (compressive and tensile), therefore cannot be considered as structural elements. In designing paper-wax tiles, the inserted paper is supposed to play an important role as reinforcement to support the wax within the frame, therefore the choice of paper type and its form is of prime importance. To test the structural ability of the paper-wax tiles to withstand the maximum wind-load in relation to the site condition, each paper-wax tile will be placed on top of a wooden frame, supported at four corners from bellow. The structural performance of the paper tiles will be tested and determined by placing weight in the middle of each tile. Weights will be placed on the tiles for at least 10min to allow the plastic deformation to occur (if there is any). Individual tiles will be tested up to the point when the first cracks appear in the wax, as it is at this point that the wax and paper insertions lose their structural strength and the ability to prevent water penetration. The deflection (if there is any) of each tile will also be measured and considered towards the final conclusion. Three different types of tiles will be tested at 3mm, 6mm, 9mm, 12mm and 15mm thickness. weight

Supporting structure for the test

Testing with gradually increased weight 51

Fig. 54 Structural force diagram of the test:

Fig. 55 Stress strain curve diagram:

Hypothesis: â&#x20AC;˘ â&#x20AC;˘

â&#x20AC;˘

At 3mm thickness, tile type 1 will probably has the best structural performance, as type 2 and type 3 both need certain thickness in order for the paper insertions to start acting as structural reinforcement. At 6mm-9mm thickness, tile type 3 will probably has the best structural performance, as: the paper cut reinforcement of type 1 stays the same at all thickness which means the changing structural ability of the tile is only depend on the thickness of wax itself for type 1; the honeycomb paper reinforcement of type 2 works better when its thicker to hold the wax together under pressure; 6mm is appropriate thickness for the thread and shredded paper to work together as reinforcement to provide both compressive and tensile strength. At 12mm thickness or above, tile type 2 is likely to have the best structural performance as the structural strength of the honeycomb paper increases as the thickness of the tile increases where as for type 1 and 3, the structural strength of the reinforcement stops increasing at certain thickness. 52

Test tile 1 - type 1 @ 3mm

Weight (kg)

Effect

0.25

Unaffected

0.50

Unaffected

0.75

d: 0.5mm

1.00

d: 1.0mm

1.25

d: 1.5mm

1.50

d: 1.5mm

1.75

d: 2.0mm

2.00

Cracked ( t: 10 sec)

where, “d” stands for the deflection, “t” stands for the time of the weight placed on the tile before the crack appears.

Test tile 2 - type 2 @ 3mm

Weight (kg)

Effect

0.25

Unaffected

0.50

Unaffected

0.75

Unaffected

1.00

d: 0.5mm

1.25

d: 0.5mm

1.50

d: 1.0mm

1.75

d: 1.0mm

2.00

Cracked ( t: 3 sec)

Test tile 3 - type 3 @ 3mm

Weight (kg)

Effect

0.25

Unaffected

0.50

Unaffected

0.75

d: 0.5mm

1.00

d: 1.0mm

1.25

d: 1.0mm

1.50

d: 1.0mm

1.75

d: 1.5mm

2.00

d: 1.5mm

2.25

d: 1.5mm

2.50

Cracked ( t: 20 sec)

Test tile 4 - type 1 @ 6mm

Weight (kg)

Effect

2.00

Unaffected

2.50

Unaffected

2.75

Unaffected

3.00

Unaffected

3.25

d: 0.5mm

3.50

d: 1.0mm

3.75

d: 1.5mm

4.00

Cracked ( t: 5 min)

Test tile 5 - type 2 @ 6mm

Weight (kg)

Effect

2.00

Unaffected

2.50

Unaffected

2.75

Unaffected

3.00

d: 1.0mm

3.25

d: 1.5mm

3.50

Cracked ( t: 5 min)

Test tile 6 - type 3 @ 6mm

Weight (kg)

Effect

2.00

Unaffected

2.50

Unaffected

2.75

Unaffected

3.00

Unaffected

3.25

Unaffected

3.50

d: 0.5mm

3.75

d: 1.0mm

4.00

d: 1.0mm

4.25

d: 1.5mm

4.50

Cracked ( t: 2 min)

Test tile 7 - type 1 @ 9mm

Weight (kg)

Effect

5.00

Unaffected

6.00

Unaffected

7.00

Unaffected

8.00

d: 0.5mm

9.00

d: 0.5mm

9.50

d: 1.0mm

10.00

d: 1.0mm

10.50

d: 1.0mm

11.00

d: 1.5mm

11.50

d: 1.5mm

12.00

Cracked ( t: 2 sec)

Test tile 8 - type 2 @ 9mm

Weight (kg)

Effect

4.00

Unaffected

4.50

d: 1.0mm

5.00

Cracked ( t: 20 sec)

Test tile 9 - type 3 @ 9mm

Weight (kg)

Effect

5.00

Unaffected

6.00

Unaffected

7.00

Unaffected

8.00

Unaffected

9.00

Unaffected

9.50

d: 0.5mm

10.00

d: 0.5mm

10.50

d: 1.0mm

11.00

d: 1.0mm

11.50

d: 1.0mm

12.00

d: 1.5mm

12.50

d: 1.5mm

13.00

Cracked ( t: 15 sec)

Test tile 10 - type 1 @ 12mm

Weight (kg)

Effect

13.00

Unaffected

14.00

Unaffected

15.00

Unaffected

15.50

d: 0.5mm

16.00

d: 0.5mm

16.50

d: 1.0mm

17.00

d: 1.0mm

17.50

Cracked ( t: 20 sec)

Test tile 11 - type 2 @ 12mm

Weight (kg)

Effect

6.00

Unaffected

6.50

Unaffected

7.00

Unaffected

7.50

d: 0.5mm

8.00

d: 0.5mm

8.50

d: 1.0mm

9.00

Cracked ( t: 2 sec)

Test tile 12 - type 3 @ 12mm

Weight (kg)

Effect

13.00

Unaffected

14.00

Unaffected

15.00

Unaffected

15.50

d: 0.5mm

16.00

d: 1.0mm

16.50

Cracked ( t: 3 sec)

Test tile 13 - type 1 @ 15mm

Weight (kg)

Effect

18.00

Unaffected

19.00

Unaffected

20.00

Unaffected

21.00

d: 0.5mm

21.50

d: 0.5mm

22.00

d: 1.0mm

22.50

d: 1.0mm

23.00

d: 1.0mm

23.50

Cracked ( t: 2 min)

Test tile 14 - type 2 @ 15mm

Weight (kg)

Effect

10.00

Unaffected

11.00

Unaffected

11.50

Unaffected

12.00

Unaffected

12.50

d: 0.5mm

13.00

d: 0.5mm

13.50

d: 0.5mm

14.00

d: 1.0mm

14.50

Cracked ( t: 10 sec)

Test tile 15 - type 3 @ 15mm

Weight (kg) 18.00

Effect Unaffected

19.00

Unaffected

20.00

Unaffected

21.00

Unaffected

22.00

Unaffected

23.00

d: 0.5mm

24.00

d: 0.5mm

25.00

d: 0.5mm

25.50

d: 1.0mm

26.00

d: 1.0mm

26.50

d: 1.0mm

27.00

d: 1.0mm

27.50

d: 1.0mm

28.00

d: 1.0mm

28.50

Cracked ( t: 5 min)

Summary and conclutions on Structural performance

Structural performance test results:

Test Parameters

Type 1 Tiles 3mm

6mm

9mm

12mm

15mm

Deflection starts at, Kg

0.75

3.25

8.00

15.50

21.00

Max. deflection at Kg Mm

1.75 2.0

3.75 1.5

11.50 1.5

17.00 1.0

23.00 1.0

2.00

4.00

12.00

17.50

23.50

2 sec

5 min

2 sec

20 sec

2 min

Centre

Collapse

Centre

Slow

Total collapse

Fast

Slow

None

Slight bend from wax shrinkage

No change

Cracking; - appear at kg - time under weight - starting point - speed of spreading - pattern in relation to paper shape Tile Integrity

Test Parameters

Type 2 Tiles 3mm

6mm

9mm

12mm

15mm

Deflection starts at, Kg

1.00

3.00

4.50

7.50

12.50

Max. deflection at Kg Mm

1.75 1.0

3.25 1.5

4.50 1.0

8.50 1.0

14.00 1.0

2.00

3.50

5.00

16.50

14.50

3 sec

5 min

20 sec

3 sec

10 sec

Centre

Everywhere

Centre

Fast

Simultaneous

Fast

Similar

None

Similar

Slight bend from wax shrinkage

No change

Cracking; - appear at kg - time under weight - starting point - speed of spreading - pattern in relation To paper shape Tile Integrity

Test Parameters

Type 3 Tiles 3mm

6mm

9mm

12mm

15mm

0.75

3.50

9.50

15.50

23.00

Max. deflection at Kg Mm

2.25 1.5

4.25 1.5

12.50 1.5

16.00 1.0

28.00 1.0

2.50

4.50

13.00

16.50

28.50

20 sec

2 min

15 sec

3 sec

5 min

Edges

Centre

Everywhere

Slow

Simultaneous

None

Slight bend from wax shrinkage

No change

Small air bubbles

No change

Deflection starts at,

Cracking; - appear at kg - time under weight - starting point - speed of spreading - pattern in relation To paper shape Tile Integrity

Comparative structural performance diagrams of the 3 types of tiles:

weight (kg)

Tile type 03

weight (kg)

Tile type 02

weight (kg)

Tile type 01

28.5

23.5

17.5

16.5 14.5 13.0

12.0 9.0

5.0

4.0

4.5

3.5 2.0

2.0 3

tile thickness (mm)

2.5

tile thickness (mm)

tile thickness (mm) 71

Based on the structural performance test, it is clear all three types have a better structural ability than expected and should be able to withstand the maximum wind speed in Beijing. As even the 3mm tile can withstand almost 2kg weight, which equals almost 19.6 Newton of external force applied to the tile. (Based on Newtonâ&#x20AC;&#x2122;s Second Law, F=mg, force equals mass times gravity). Test results came out very different to the speculated structural performance. Structural performance diagrams show that tile type 3, with cotton threads and shredded paper, withstood the heaviest weight at most tile thicknesses. This implies that the combination of cotton mesh and paper strips is structurally the best reinforcement of the three insertions tested. Tile type 1 (paper cut as reinforcement) Analysing results for all three types and observing cracks formed by type 1 tiles with different thicknesses suggest that type 1 has a structural ability close to the structural ability of paraffin wax on its own and the paper cut insertions donâ&#x20AC;&#x2122;t improve nor reduce the structural ability of the tile, which may explain why crack shapes were not influenced by the patterns of the paper. Tile type 2 (honey-comb paper as reinforcement) Tile type 2 has the worst structural performance. Contrary to the hypothesis, the thicker the tile, the worse the structural performance compared to the other two types. When the tile reached the thickness of 15mm, type 2 could only withstand almost half the weight compared to the others. Therefore it is concluded that the honey-comb paper insertion didnâ&#x20AC;&#x2122;t improve the structural ability of the wax tile but reduced it dramatically by breaking the macro-crystalline structural bond of the wax with the honey-comb divisions, evident from the crack lines always following the honey-comb pattern of the insertion with a fast cracking process. Tile type 3 (cotton mesh and paper strips as reinforcement) Of the three insertions tested, type 3 has the best structural performance probably because the cotton mesh offers both tensile strength and flexibility, allowing the tile to stretch slightly with the wax and return to its original shape after deformation. A lesson learned from tiles type 2 and 3 in test 3, which could be the potential problem with type 3 is: the paper strips wave through the cotton mesh in all directions, the wider the strips the weaker the tile might get, as the paper strips reduce the tensile strength of the tile by breaking the macro-crystalline structural bond within the wax. Another aspect that might affect the structural performance of the tile, discovered from test 12 is the temperature during wax congealing process. The warmer the temperature (closer to the congealing point), the longer the congealing process, the better the wax quality. Cold temperature dramatically increases the congealing speed, leading to a wax tile with small bubbles sealed in or potential distortions affecting the structural performance of the wax.

Type 4 - Additional tests In order to prove the above two hypothesis, further tests will be carried out comparing the structural performance of tiles type 4a, 4b, 4c to the previous types at the thickness of 6mm, where Type 4a has cotton mesh as reinforcement, congealed at high room temperature; Type 4b has only paraffin wax, congealed at high room temperature; Type 4c has only paraffin wax, congealed at winter outdoor temperature.

Test tile 16 - type 4a @ 6mm

Weight (kg)

Effect

2.00

Unaffected

2.50

Unaffected

2.75

Unaffected

3.00

Unaffected

3.25

d: 0.5mm

3.50

d: 1.0mm

3.75

d: 1.5mm

4.00

Cracked ( t: 1 min)

Test tile 17 - type 4b @ 6mm

Weight (kg)

Effect

2.00

Unaffected

2.50

Unaffected

2.75

Unaffected

3.00

d: 0.5mm

3.25

d: 1.0mm

3.50

Cracked ( t: 10 sec)

Test tile 17 - type 4b @ 6mm

Weight (kg)

Effect

2.00

Unaffected

2.50

Unaffected

3.00

Unaffected

3.25

d: 0.5mm

3.50

d: 1.0mm

4.00

d: 1.0mm

4.50

d: 1.0mm

5.00

d: 1.0mm

5.50

d: 1.0mm

6.00

d: 1.5mm

6.50

d: 1.5mm

7.00

d: 1.5mm

7.50

d: 1.5mm

8.00

Cracked ( t: 5 sec)

Summary and conclusions on additional structural performance From the comparative table bellow, it can be seen that, the result of the additional test didnâ&#x20AC;&#x2122;t really match the earlier hypothesis. The type 4c (congealed with cold temperature), which was speculated to have the lowest structural ability had the best structural performance. It proves that instead of reducing the structural strength, the quick congealing process improves the rigidity of the paraffin wax dramatically. The type 4a (cotton mesh reinforcement, congealed at high room temperature) and 4b (paraffin wax congealed at high room temperature) had similar structural performances to the type 1 (paper cut reinforcement) and type 3 (cotton mesh with paper strips reinforcement), showing that the paper reinforcement didnâ&#x20AC;&#x2122;t really affect much of the structural performance of the Paper-wax tiles.

6mm Tiles Test Parameters

Type1

Type 2

Type 3

Type 4a

Type 4b

Type 4c

Deflection starts at, Kg

3.25

3.00

3.50

3.25

3.00

3.25

Max. deflection at Kg Mm

3.75 1.5

3.25 1.5

4.50 1.5

3.75 1.5

3.25 1.0

7.50 1.5

4.00

3.50

4.50

4.00

3.50

8.00

5 min

2 min

1 min

10 sec

5 sec

Centre

Slow

Fast

Slow

Fast

Collapse Total collapse

None

Similar

None

N/A

Slight bend from wax shrinkage

Cracking; - appear at kg - time under weight - starting point - speed of spreading - pattern in relation To paper shape Tile Integrity

TEST 2: THERMAL PERFORMANCE The aim of this section is to study the thermal performance of paraffin wax as a wall tile material, in relation to Building Regulation standards. This will be tested through the calculation of thermal conductivity. This test will calculate: a. The thickness of paper wax tiles necessary to reach the required U-value for the wall of a domestic dwelling b. The thickness of paper wax tiles needed to match the standard U-value of a single glazing construction c. The U-value of the tiles used in this thesis tests (3mm, 6mm, 9mm ,12mm and 15mm) Hypothesis: The paper insertions will have little contribution to the thermal performance of the tiles. Therefore the thermal performance is largely depending on the property of wax. Due to waxâ&#x20AC;&#x2122;s relatively high thermal conductivity, it is unlikely for the paper-wax tile to reach the U-value required for a wall unless it is really thick (possibly 1meter thickness). But it is possible that the wax tile will have a better thermal performance than a single glazing construction at the same thickness.

Equations and definitions The thermal performance of the wall, roof or floor of a building is described by its U-value. A U-value is the thermal transmittance, which is the overall rate of heat transfer under steady state conditions through 1 square meter of a crosssection of a building element when the temperature on each side of the structure differs by 1掳C. The coefficient is expressed in watts per square metre per degree Kelvin, W/m2K Modern house have typical U-values of around: 0.35 W/m2K for walls 0.25 W/m2K for roofs 0.45 W/m2K for floors 3.10 W/m2K for windows The U-value of a structural element is given by,

U-value = 1/Rt

where Rt is the sum of the resistances of surfaces and layers of material. Rt = Rsi + R1 + R1 + R2 + ...... + Rn + Rso where Rsi is the resistance of the inner surface. R1, ...Rn are the resistances of the layers of material, Rso is the resistance of the external surface. The thermal resistance of a layer of material depends upon the conductivity per unit of thickness,

R = d/ 位 (m2 K/W)

where d is the thickness of the material, m 位 is the thermal conductivity of the material, W/mK The thermal conductivity is a measure of the rate at which heat passes through a material. It is expressed in terms of watts per square metre for a 1 metre thickness and a temperature difference of 1 Kelvin. The lower this figure, the better the insulation value. Typical material thermal conductivity : 0.19 W/mK for light weight concrete block 0.84 W/mK for outer leaf brickwork 0.14 W/mK for timber flooring 0.035 W/mK for EPS insulation 79

The thickness of tile necessary to reach the required U-value for the wall of a domestic dwelling As defined by the Building Regulations in China, the required U-value for the wall of a domestic dwelling is 0.45 W/m2K. Based on the thermal conductivity given by “The Engineering Toolbox” and “Experimental results for Thermal Conductivity of Paraffin Waxes”, The thermal conductivity of Paraffin wax, λw is 0.235 W/mK The thermal conductivity of paper, λp is 0.05 W/mK Using the earlier equations:

U-value = 1/Rt = 1/ Rsi + Rw + (Rp) + Rso

where Rw is the thermal resistance of wax and Rp is the thermal resistance of paper. But since all the paper insertions used in the tile casting are thin and extremely porous, even though paper has a low thermal conductivity, they contribute very little to the insulation value of the tile. Therefore the total resistance will be calculated using wax as the main material.

Rsi + Rw + Rso = 1/ U-value

Rw = dw/ λw = ( 1/ U-value ) - Rsi - Rso

dw = λw x [ ( 1/ U-value ) - Rsi - Rso ]

where Rsi is 0.30 m2 K/W and Rso is 0.07 m2 K/W for low emissivity of surface and with normal exposure.

dw = 0.235 x [ (1/ 0.45) - 0.3 - 0.07 ]

dw = 0.235 x 1.852

dw = 0.435 m

Therefore, the thickness of Paraffin paper wax tile necessary to reach the required U-value for the wall of a domestic dwelling is 435mm, which proves paraffin paper wax tile has a much better thermal performance than I speculated.

The thickness of tile that matches the standard U-value of a single glazing construction Based from the previous equation,

U-value = 1/Rt = 1/ Rsi + R + Rso

In order to find out the thickness of the tile that matches the standard U-value of a single glazing construction, the thermal resistance of the tile and glass must be equal, assuming that the emissivity and site exposure are taken to be the same for the tile and glass, Rw = Rg Where

Rw is the resistance of the wax, Rg is the resistance of the glass.

Since,

R = d/ λ

Rw = Rg = dw/ λw = dg/ λg

Based on the thermal conductivity given by “The Engineering Toolbox”, a single sheet of 3mm thick glass which is used in single glazing has a thermal conductivity of 1.05 W/mK.

dw = ( dg/ λg ) x λw

dw = (0.003 / 1.05 ) x 0.235

dw = 0.00067 m

Therefore, the thickness of paraffin wax tile that matches the standard U-value of a single glazing construction of 3mm, would be only 0.67mm thick, which proves paraffin paper wax tile a much better thermal storage than glass.

The U-value of the tiles used in this thesis tests The thickness of the paper wax tiles used in the test are 3mm, 6mm, 9mm, 12mm and 15mm. Based on the previous equation,

U-value = 1/Rt = 1/ Rsi + Rw + Rso

And,

Rw = dw/ 位w

Therefore,

U-value = 1/ ( Rsi + dw/ 位w + Rso )

Where

Rsi is the inside surface resistance, 0.30 m2 K/W Rso is the outside surface resistance, 0.07 m2 K/W dw is the thickness of the tile, 0.003m, 0.006m, 0.009m, 0.012m and 0.015m 位w is the thermal conductivity of wax, 0.235 W/mK

U-value of 3mm tile = 1 / (0.30 + (0.003/0.235) + 0.07) = 2.61 W/m2K

U-value of 6mm tile = 1 / (0.30 + (0.006/0.235) + 0.07) = 2.52 W/m2K

U-value of 9mm tile = 1 / (0.30 + (0.009/0.235) + 0.07) = 2.44 W/m2K

U-value of 12mm tile = 1 / (0.30 + (0.012/0.235) + 0.07) = 2.37 W/m2K

U-value of 15mm tile = 1 / (0.30 + (0.015/0.235) + 0.07) = 2.30 W/m2K

Therefore, the U-value achieved by the paraffin paper wax tiles used in this thesis test are, 2.61 W/m2K for 3mm thickness, 2.52 W/m2K for 6mm thickness, 2.44 W/m2K for 9mm thickness, 2.37 W/m2K for 12mm thickness and 2.30 W/m2K for 15mm thickness, which are all better than the U-value of a double glazed window at 3.10 W/m2K

Summary and conclutions of thermal performance From the calculations above: The thickness of Paraffin paper wax tile necessary to reach the required U-value for the wall of a domestic dwelling is 435mm. Even though the calculated result proves paraffin wax tiles a better insulation material than speculated, the thickness is far too large for a wall tile to reach the required thermal performance. Also in relation to the concept of the paper-wax tile as translucent threshold, at this thickness It would be almost completely opaque. To reduce the thickness of tiles but keep the ideal thermal performance similar to a wall, a possible way could be adding air cavities in between thin layers of wax, as air has a very low thermal conductivity of 0.024 W/mK, which could dramatically improve the U-value of the tile without affecting the light transmission performance. The thickness of Paraffin paper wax tile that matches the standard U-value of a 3mm single glazing construction is 0.67mm. The thickness of the tile that achieves the same thermal performance as single glazing is less than a quarter of the thickness of the glass. This indicates that, if it could be used in the same quantities and locations on a building as single glazed windows, with a similar thickness to the glass, then the thermal performance of the building would be improved greatly. The U-value of the different thickness of tiles used in this thesis tests are between 2.61 to 2.30 W/m2K for thickness from 3mm to 15mm. When compare the U-values of the tiles to different glazing units with wood frame, based on the figures from â&#x20AC;&#x153;Conservation of fuel and power, Approved Document L1, Tables of U-valuesâ&#x20AC;?, Single glazing 4.8 W/m2K Double glazing 3.1 W/m2K (6mm air gap between panes) Double glazing 2.8 W/m2K (12mm air gap between panes) Triple glazing 2.4 W/m2K (6mm air gap between panes) Triple glazing 2.1 W/m2K (12mm air gap between panes) It can be seen that, under the same condition, even the thinnest paper-wax tile (3mm) has better thermal performance than the single or double glazed windows. Its U-value of 2.61 W/m2K gives a thermal performance comparable to that of a double glazing with a 12mm air gap. Taking the glass to be 5mm thick, the total thickness of this glazed unit would be greater than 22mm, compared with the 3mm of the paraffin paper-wax tile.

TEST 3: LIGHT TRANSMISSION PERFORMANCE (light transmittance and quality of shadow) As a translucent material, wax never allows all of the light falling on it to pass through, reducing the illumination of the interior space in relation to the exterior space. The light transmitted through the tiles will depend on: a. the type and quantity (in the case of type 3) of paper insertions cast within the tile b. the thickness of the wax As an important part of the concept of the translucent threshold, the shadow of the occupier of the lit interior space, when cast onto the wax wall, must be visible and reasonably clear from the exterior space in order to describe a magnification of the occupation; also a decent amount of day light must be allowed to enter the room for day time indoor activities. Therefore the paper wax tile must be of an appropriate thickness to allow these to happen.

3 types of tiles will be tested at thickness of 3mm, 6mm, 9mm, 12mm and 15mm, the result will be used to study: â&#x20AC;˘ â&#x20AC;˘

Light transmission performance of 3 different paper insertions cast into a constant thickness of wax Light transmission performance of tiles with the same paper insertions at different thicknesses

In order to test the light transmission performance of the wax paper tiles, a 40 Watt light source was set up in a dark room, at a point 0.5m away from, and perpendicular to, the plane of the tile, and the object casting the shadow at 0.1m from the tile, in order to visually compare the shadows. The position of the tile, object, and light source were chosen to simulate a typical domestic scale of space at 1:5 scale. (Assumed in the typical domestic scale, light source would be around 200 Watt, 2.5m away from the wall, and the objects would be casting shadows at 0.5m from the wall.) The shadow in the tests was casted by a human hand, to give a direct human scale to the study. The results were compared in the form of photographs, as the non-technical nature of the study allows for only a comparative analysis of the results.

wax tile

object

0.1m/0.5m

light source (40W/200W)

0.5m/2.5m

Hypothesis: • • • •

at 3mm -6mm thickness, all three types will give a clear shadow and allows decent amount of daylight to pass through. at 9mm thickness, type 1 and 2 will give a clear shadow but type 3 will start losing its ability to cast clear shadow as light gets diffused through the shredded paper strips. at 12mm thickness, type 1 will fail in casting clear shadow and type 3 will fail in passing decent amount of day light. Only type 3 still gives a clear pixelated shadow. at 15mm thickness, type 3 still gives a reasonable pixelated shadow, the other two types fail in both casting shadow and passing light.

Light transmission performance of 3 tile types @ 3mm thickness

Type 01 - paper cut insertion -