Blog: Week 2 | Material Expression
- up915094
- Feb 18, 2022
- 18 min read
Updated: Aug 4, 2022
EXPLORE | Detail and Material
Key words: Exploration, detail, environmental impacts, finite resources.
"The details are not the details, they make the design." - Charles Eames
For week two, we were asked to look at materials in the real world, in which two or more materials come together in an interesting way. The first case study I chose was The British Museum, as when I visited I thought the roof was really impressive. I thought it would be interesting to explore the way in which the steel and glass interact with each other on a detailed level.
First Detail Exploration: The Great Court
"The great court is spellbinding enough to detain all who wander there. Walking in from the entrance hall is like entering a magical realm, where everything seduces us with a radiant apprehension light’s transfiguring power." - The Times
The Great Court was opened 20 years ago, in December 2000. Today, this space is one of the most recognisable and frequently photographed parts of the museum, mainly due to the spectacular ceiling. The tessellating glass roof is made up of 3,312 individual panels of glass, which are supported by a 478-tonne steel structure. It was engineered by Buro Happold to a design by Foster + Partners, and built by Austrian specialists Waagner-Biro. The funding for the project came from the 'Raising the roof' campaign, which involved donations made in memory or honour of a loved one.
Photos from Visit
These are some of the photos I took when I visited The British Museum.
Historical Context
Before the construction of the Great Court, in the centre of this space was The Reading Room. This housed books for the British library and consisted of cast iron, concrete and glass. It has a diameter of approximately 42.6 metres and was inspired by the domed Pantheon in Rome. It was constructed in segments on a cast iron framework, with a paper mâché ceiling suspended on cast iron struts hanging down from the frame. They were joined by walkways at different levels, and an internal labyrinth of corridors.
The Reading Room featured 38 tables for 302 readers at a time, all radiating out from the keyhole-shaped catalogue desk. The tables were padded and covered in black leather and the floor was covered in a special material that was designed to reduce noise.
Some of the iron work within the library was badly damaged during an air strike in WWII, and the quadrants of the Iron Library have now been demolished. Various structures were put into this space over the years, but all were removed, including the bookcases, by the time the Great Court was built in the late 1990s.
How Are The Materials Joined?
Waagner-Biro designed the geometry of The Great Court Roof to span the entire breadth of the space using a customized form generating program. It consists of a steel lattice constructed from steel box beams joined in a six-way node, which connect the glass panels.
20 composite steel and concrete columns hidden in the exterior cladding of the Reading Room take the weight of the canopy while also aligning the room’s original cast-iron frame. I have included my technical drawing showing how the steel and glass fit together in more detail.
Analytical Drawing of the Roof
This analytical drawing shows the detail, separated into its main components. The steel beams slot into the six way steel node connection axis. This is then secured to thinner sheets of the same form using the embedded steel nuts, which slot into perforated holes within the thinner steel beams.
These are also fixed down with the second component to the steel node connection axis, which fits over the top. This allows the double glazed glass panels to sit above the framework. Joint stiffness is established to minimize stress concentrations in glass. Once these components are all together, they are fixed with a solid silicone seal over the top of the glass pane.
These are some details of the façade, showing its components in greater detail.
The redesign of the Great Court also houses two new gallery spaces: The Sainsbury Galleries, with a display of objects from the Museum's Africa collection; and the Welcome Trust Gallery, home to a series of long-term, cross-cultural, thematic exhibitions, currently based around Living and Dying. A new space for temporary exhibitions, Room 35 – The Joseph Hotung Great Court Gallery – was also built.
The Body and Materials
The surface of the glass is translucent, allowing plenty of light to pass through the material and into the Great Court. This creates an interesting interaction with the rest of the materials in the interior, as the opaque steel beams block out triangular outlines. The contrast of the shadows against the light Balzac limestone flooring and creamy coloured French limestone walls extends the beautiful effect of the ceiling throughout the whole of the interior. This means that, despite the height of the ceiling, the body does in fact react with the material as people pass through the shadows. Visual senses are engaged as the shadows from the steel beams block out patterns of sunlight. As I was visiting, I felt that this created the effect of the ceiling 'wrapping' around the entire room as it reached to vast areas of the interior.
The Making of Steel
To make steel, iron ore is heated and melted in furnaces where the impurities are removed and carbon is added.
A few of the steel making processes which I will be investigating are:
Blast Furnace
BOS steelmaking
Blast furnaces mainly use the raw materials of iron ore, limestone and coke, with some scrap steel, whereas Electric Arc Furnaces use mainly scrap steel. BOS steelmaking also utilises scrap steel.
This is a YouTube video which I used as my starting point for gaining a basic understanding of different steelmaking processes, which I go into detail about within this blog post.
Blast Furnace Method
In the 1850s, the blast furnace was invented by and Englishman names Henry Bessemer. This method involved blowing air through molten iron to oxidize the material and separate impurities in order to produce steel.
A modern version of the blast furnace is a large, steel, cylinder shell, lined with brick which is heat-resistant.
Iron ore, coke and limestone are fed into the furnace from the top and gradually sink down towards the bottom, getting hotter as they go down.
In the top part of the furnace, gas from the burning coke releases oxygen from the iron ore. In the bottom half of the furnace, limestone starts to react with the impurities in the ore and coke forming a molten slag as the temperature reaches over 1600°C.
This results in the molten slag floating above the molten steel, which can then be drained via a slag notch in the furnace.
The end result is molten steel released from the hearth of the furnace through a tap hole.
EAF Method
This method is primarily utilised for special quality steels that are alloyed with other metals, but EAFs can also produce ordinary, non-alloyed steels. EAF's also use scrap steel from recycled products rather than hot metal.
The scrap steel is tipped into the EAF from an overhead crane.
When the furnace is full, the lid containing electrodes is closed, and the electrodes are lowered into the furnace. These are charged with a powerful electric current that generates heat, in order to melt the scrap.
As the scrap melts, other metals known as ferro-alloys are added to the steel, giving it the desired chemical composition.
Oxygen is then blown into the furnace to purify the steel. The addition of lime and fluorspar result in fusing of the impurities and the formation of slag.
The molten slag floats above the molten steel and is then poured off as the furnace is tilted.
Many special quality steels can be made in EAF’s by combining other metals to form these steel alloys. For example, stainless steel, is a popular building material which has chromium and nickel added to make it more corrosion-resistant.
The Making of Glass
Glass is made up of different natural materials, which are melted at a very high temperature. In this state, the structure of glass is similar to that of a liquid, and once cooled down it behaves more like a solid. This makes it a material with a lot of flexibility to be poured, blown, pressed and moulded into a variety of shapes.
Within the glass industry, there are a variety of production processes, depending upon the desired end result. Almost all of which have been known to us since ancient times, with many of the tools since the discovery of glass-blowing in 1st Century B.C still being utilised . However, furnaces, technology, mass production-methods and chemistry have advanced since then. This is primarily due to the industrial revolution, which resulted in advancements in acid-etching, sand-blasting and mechanical pressing over the past 200 years. I decided to investigate the primary method of glass making which is most relevant to the construction industry - the process of making glass panels.
The process of modern production of glass panels is as follows:
Sand, soda ash, dolomite, limestone and salt cake are combined.
These materials are then mixed with surplus glass and heated in a furnace to 1500°C. The furnace is able to contain over 1200 tonnes of glass at once.
As the glass is melted, it is then brought to a temperature of 1200°C.
The glass is fed into a bath of molten tin. This is perfect for the glass-making procedure as tin mixes with the glass very well.
The glass floats upwards and onto the tin surface, morphing into a sheet. The temperature is the lowered, and the sheet is lifted onto rollers. Here, varying flow and roller speeds produces sheets of different thicknesses and widths.
Then, the glass is cooled and reheated at a slow rate in order to increase strength and prevent shattering. Or it can be tempered, meaning it is heated and then chilled with quick blasts of cold air.
The glass may be glazed and coated with insulated window glazes, heat absorbing tints, or other coatings.
Environmental Impacts of Glassmaking
Glass is often considered an environmentally sustainable material as its production doesn't require fossil fuels, it is infinitely recyclable/reusable and it doesn't leach out any harmful chemicals during use. It can be seen as a preferable material to plastic, as it is a stable material which doesn't react with the majority of chemicals. Plastic containers can leak harmful toxins and microplastics, making this an unsuitable choice for the long term storage of food or water.
As glass can be recycled infinitely without losing its quality, this reduces the need for new glass production which requires raw materials and energy. Less energy is also needed throughout the recycling process than there is during new production. However, not all glass can be recycled, depending on its production process.
Although glassmaking doesn't directly utilise fossil fuels as a direct raw material, its extraction, processing and transportation needs large amounts of energy. This is primarily derived from fossil fuels. Due to its weight, glass requires more energy during transportation than lighter materials. Glass also utilises sand, which is a finite resource. This is the most used natural research on earth, behind water. The over-extraction of sand has a negative impact on surrounding ecosystems, contributing to erosion and flooding.
"We cannot extract 50 billion tonnes per year of any material without leading to massive impacts on the planet and thus on people’s lives" - Pascal Peduzzi
This is a worldwide issue, with sand used annually in India tripling since 2000 and still rising quickly. Within the past decade, China has utilised the resource in greater amounts than the US did throughout the whole of the 1900s. Dubai requires so much sand that it is imported from Australia.
Ocean dredging is a process of extracting sand in which sediments and debris are removed from the bottom of lakes, rivers, harbours, and other water bodies. This has damaged coral reefs all over the world, in areas such as Florida, the Persian Gulf and Kenya. Unfortunately, this process ruins marine habitats and muddies waters with sand plumes, affecting aquatic life on a widespread scale. This also has negative impacts on the livelihoods of fishermen, particularly in Cambodia and Malaysia. China has seen wiping out of coastal wetlands, with the destruction of habitats for fish and birds, alongside an increase in water pollution.
Some other environmental downsides to the use of glass as a building material are:
It takes one million years to decompose in landfills.
More resources are required during production than when plastic is made.
It is easily broken, meaning it is more likely to be thrown away.
Recycling can actually be ineffective.
Second Detail Exploration: The Mary Rose Museum
For my second detail exploration, I decided to visit The Mary Rose Museum in Portsmouth historic dockyard. This is a museum which displays the 16th Century Tudor warship called The Mary Rose. Its purpose was primarily to house and preserve the remains of the warship, alongside artefacts relevant to this. This ship served the navy of King Henry VIII for 33 years until it sunk, remaining undiscovered for 437 years at the bottom of the sea.
Photos from Visit
These are some photos that I took when I visited The Mary Rose Museum.
Historical Context
The Mary Rose was built in 1511 under the reign of Henry VIII, who was an enthusiastic shipbuilder. His pride in his "Army by Sea" saw his fleet of ships grow from 5 to 58 throughout the duration of his reign, which lasted from 1491 until his death in 1547. Today, he is known as "the father of the Royal Navy", as he heavily funded the navy, contributing to its growth and establishing the Navy Board.
The Mary Rose sank in 1545, in the Solent, which is located in between Portsmouth and the Isle of Wight. The Mary Rose was part of an English fleet trying to stop the French ships landing on the Isle of Wight, but unfortunately sank before firing a single shot.
"Next day, Sunday [19 July], while the King was at dinner on the flagship, the French fleet appeared. The King hurriedly left the flagship and the English sailed to encounter the French, shooting at the galleys, of which five had entered the harbour while the English could not get out for want of wind. Towards the evening the ship [the Mary Rose] of Viceadmiral George Carew foundered, all the 500 men on board being drowned save about 25 or 30 servants, sailors and the like. Was told by a Fleming amongst the survivors that when she heeled over with the wind the water entered by the lowest row of gun ports which had been left open after firing. They expect to recover the ship and guns..." - The encounter described by a sailor on board.
The Mary Rose was left undisturbed until three of the port frames were found by diver Percy Ackland in 1971. After its discovery, over 500 volunteer divers, and many volunteers on shore, helped with the work. Deck beams, frames and planking were discovered by divers at the wreck, and a series of limited excavations outside the ship were carried out to find out how much might have survived. The ship was finally raised in 1982, and over 19,000 objects were successfully recovered from the wreck.
A news report on the Raising of the Mary Rose (1982).
Detail Discussion
The detail contributes to the overall design of the space in an interesting way that encases the interior artefacts. It provides a clean finish which ties in with the rest of the design. This creates the effect of neatly wrapping around the precious historic items, as the curved timber and rolled metal roof fit perfectly around them. The body interacts with mainly the wood as it is the most consistent throughout the structure, however the metal is also present within handrails and the structural supports. The senses of touch, sound and smell were primarily engaged with the wooden surfaces, . I noted the roughness of the wood was contrasted with the smoothness of the metal. As I was walking through the museum, the sound of my footsteps was the most overwhelming sense that was engaged, as it was quite dark.
Materials and Pre-Construction Process
Today, the wreckage is preserved using a structure made up of stained timber panels and a metal roof. It was designed by architects Wilkinson Eyre, Perkins + Will and built by the construction company Warings. The construction was difficult to do, as the museum needed to be built over the original Mary Rose ship in the dry dock, which is a listed monument. Throughout the construction process, the hull was conserved inside a sealed "hotbox". In 2013, the polyethylene glycol (PEG) sprays which helped to slowly replace the water within the timber were turned off, and the process of controlled air-drying began.
How was it Made?
This YouTube video provides a visual illustration of how the Mary Rose Museum was constructed (1:27-2:11).
The Mary Rose Museum was contracted by the Mary Rose Trust, and is built using a steel superstructure and curved external envelope which was built around the Mary Rose Ship. A standing seam roof to wall detail was likely used to join the rolled metal roof to the structural frame.
Standing Seam Roof to Wall Detail
The kind of joinery that is commonly used within details joining a rolled metal roof to its surrounding walls is a standing seam roof to wall detail. Below, I have included my own detail drawing of this type of detail.
This detail that I drew from The Mary Rose Museum shows the kind of joinery that is commonly used to secure a rolled metal roof to its surrounding walls. The detail features an accepted deck base, underneath an underlayment membrane. This is covered with a membrane flashing, which wraps vertically and horizontally around the remaining elements. The J-channel has a horizontal fold, which sits on top of the metal roof panel with pan end fold. Perpendicular to the aforementioned component, is the metal base flashing, which sits underneath the underlayment membrane.
This metal roofing system uses these hidden fasteners, so that the hardware used to secure the panels to the substrate are hidden beneath the panels instead of exposed on top of them. Typically, standing seam panels are completely flat or striated, with the ridges or bumps being at the seams (or vertical legs). This allows for the clean, seamless finish as seen in the roof of The Mary Rose Museum.
Surfaces and Finishes
The first thing I noticed about the materials was their colouring. The timber is stained to match the dark metal roof, which led me to look into into different effects that could be achieved using this method. I came across this photo illustrating varying swatches of wood stains, from lighter to darker. The finish achieved within the timber used for the Mary Rose Museum is similar to that of the black swatch, which is the darkest that can be achieved.
Timber Steam Bending
In order for the wood to have the curved form which is apparent within the structure, a process of bending needs to occur. A common method of achieving this result within timber is steam bending.
Steam bending is the process of soaking a piece of wood in hot water at boiling point for a certain period of time in a steam box, softening the fibres to make it pliable and more stretchy.
A steel mould that is placed on the back of the wood while heat bending can help ensure that all the bends and curves are done to the requirements of the project being made.
After heat bending the wood, clamping it into a solid mould will reinforce the bends made to the wood while drying, preventing the wood from straightening while it dries.
This means that once the timber cools down and the fibres dry once more, it will retain its new shape.
Steam Bending Process
Environmental Impacts of Wood
As the only renewable building material, and it can be grown and harvested multiple times. The production process is more environmentally friendly than that of steel and concrete. Wood harvested from sustainably-managed forests is an environmentally conscious choice of building material, with a lower carbon footprint than other materials.
Unsustainable wood harvesting is known as deforestation. This is an ever prevalent issue within todays climate, as it contributes to the increase in greenhouse gas emissions. Entire rainforests are being cleared and burnt, which is then replaced with soy beans, rubber pasture, cattle and palm oil. Palm oil is in high demand as it is in so many of our daily products such as soap, shampoo, chocolate, bread and crisps. Habitats are disappearing at an alarming rate, and with every forest cleared there are less trees to absorb CO2, which contributes to global warming. Nearly a third of CO2 emissions are caused by deforestation.
Deforestation also results in:
A loss in biodiversity;
Disruptions to the water cycle;
Soil erosion;
Flooding.
Alternative Solutions
As consumers, we can purchase certified wood from forests which will enforce forestry practices amongst consumers and retailers, and help to eliminate environmentally destructive lumbering practices. However, our efforts cannot make much of an impact if large corporations are still carrying on with these unsustainable practices. This means that things need to change on a global scale to see any real, significant improvements. A drastic, global enforcement of sustainable forestry is desperately needed.
As I am interested in using wood within my IMP design, this research has shown me the importance of only purchasing timber from approved, sustainable forests within the UK to reduce transportation emissions and avoid supporting unsustainable forestry.
Further Steelmaking Investigation
As steel is utilised within this detail, I decided to explore another steelmaking method which I haven't previously mentioned and evaluate some of the environmental impacts of making processes. A method which I haven't yet explored is BOS steelmaking.
BOS Steelmaking
Basic Oxygen Steelmaking (BOS), which is the main production process for refining iron into steel. BOS vessels allow for up to 350 tonnes of molten iron at a time to be converted into steel in under 30 minutes.
Scrap steel is put into a vessel, alongside hot metal which may have been pre-treated to remove unwanted elements such as sulphur.
High purity oxygen is then blown onto the hot metal by a lance at an extremely high speed (almost twice the speed of sound).
The oxygen will combine with the impurities and this oxidation produces heat. The temperature is kept at a controlled level by the quantity of scrap steel, and the addition of iron ore which is acts as a coolant.
Oxidised carbon then creates carbon monoxide gas. This can be used as fuel once it is collected and cleaned.
The other oxidised impurities, combined with lime that has been added during the blow form a slag.
The quantities of scrap, hot metal, or lime and other substances are calculated to ensure the correct temperature and composition of the steel.
Refining can be assisted by injecting argon, nitrogen or oxygen gases through the base of the vessel and a sub lance is used to measure carbon and temperature during the blow to allow final adjustments to be made.
During tapping, alloy additions are also made to adjust steel composition. By this stage, the carbon has been reduced from around 4%, to around 0.05%.
Finally, the vessel is tipped to remove the slag for recycling.
I was interested to investigate BOS steelmaking and the EAF method, as the use of scrap steel and waste materials used for recycling makes it sound like an environmentally conscious method. However, I'm unsure if the energy required and inevitable emissions may override this, as the steel industry is currently amongst the three biggest producers of carbon dioxide, with emissions being produced by a limited number of locations.
Environmental Impacts of Steelmaking
This YouTube video provided me with a good overview of why steelmaking negatively impacts the environment, even when recycled steel is used.
Whilst the use of recycled steel sounds promising, only a third of steel made around the world comes from recycled steel, with the rest being produced by iron ore. Due to a worldwide demand for steel, recycled steel is not sufficient for the necessary supply. Scrap steel also contains impurities which reduces the strength of the material, making it a less desirable material for construction. This means iron ore is still mined, which is a finite resource. Making new steel from iron ore requires nearly 20X more recycled coke than recycled steel.
In 2020, the steelmaking industry produced almost 2 billion metric tonnes of steel, half of which was utilised within buildings and bridges. This means this metal will not be able to be utilised as scrap steel for a long period of time. It is predicated that within the coming decades, over 50% will still be produced from iron ore, which is an environmental issue. Steel is responsible for 24% of industry related gas emissions, primarily from new production of steel.
However, recycled steel also has a negative environmental impact. Furnaces require a huge amount of electricity, which (even when powered by renewable energy) requires the mining of coal in order to produce coke. This uses large amounts of energy and produces air pollution.
Unfortunately, annual construction waste is expected to reach 2.2 billion tons globally by 2025.
Alternative solutions
Replacement of coke with materials which would otherwise be placed in a land fill, like old rubber and plastics. However, these solutions are still in the testing process, so for now steelmaking emissions remain high. The steelmaking industry has an extremely prevalent responsibility to focus on environmentally responsible decisions and processes in order to reduce this gravely negative, unsustainable impact on the planet.
Reflections
After completing this activity, I found that I have more confidence in technical drawings and understanding the interior on a detailed scale. Drawing areas of interest really helped me to analyse the detail as a whole in a visual way. I also found it was important to look into the historical contexts of the spaces, as this contributed to my overall contextualisation of the space.
I gained a greater insight into material making processes such as steel, wood and glass, along with each of their environmental impacts. It was very interesting to explore how even materials which I believed to be environmentally conscious choices have their downsides. Glass in particular, is a natural material which before this investigation, I wasn't aware of its negative impacts on the environment. As consumers, intricately thought out marketing and the influence of powerful corporations often affects our perceptions of certain materials, and leads us to believe they are eco-friendly.
The effects of using wood as a building material was also particularly alarming. Although I was aware of deforestation and its environmental impacts, I was disappointed with how little improvement there has been with growing and harvesting processes since I last researched this topic extensively in school.
For the aforementioned reasons, this has reinforced my belief in the importance of doing independent research using academic journals which aren't heavily influenced by the media or any powerful corporations.
This activity has clarified the responsibility which lies with our selection of building materials, as it is ethically crucial for us to enter the design world with an environmentally conscious mindset. This will allow us to make a difference in ways that we can, and help to reduce unsustainable practices by lowering the demand for materials which are harmful to the planet.
References
Beiser, V. Why the world is running out of sand. (2019). https://www.bbc.com/future/article/20191108-why-the-world-is-running-out-of-sand
Bekker, J. G., Craig, I. K., & Pistorius, P. C. (1999). Modeling and simulation of an electric arc furnace process. https://www.jstage.jst.go.jp/article/isijinternational1989/39/1/39_1_23/_article/-char/ja/
Butera, F. M. (2005). Glass architecture: is it sustainable. Passive and Low Energy Cooling for the Built Environment. https://d1wqtxts1xzle7.cloudfront.net/37947462/Butera-with-cover-page-v2.pdf?Expires=1653575497&Signature=OMj5P
Ing, J. S. D. (2000). Engineering the construction of the great court roof for the British Museum. Widespan roof structures. https://books.google.co.uk/books?id=vp7u0LRgP5YC&lpg=PA199&ots=ETTXj08oB0&dq=great%20court%20roof&lr&pg=PA206#v=onepage&q=great%20court%20roof&f=false
Missbauer, H., Hauber, W., & Stadler, W., (2009). A scheduling system for the steelmaking-continuous casting process. https://www.tandfonline.com/doi/abs/10.1080/00207540801950136
Moretti, C., & Hreglich, S. (2013). Raw materials, recipes and procedures used for glass making. https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118314234.ch2
Olmez, G., Dilek, F. B., Karanfil, T., & Yetis, U. (2016). The environmental impacts of iron and steel industry: a life cycle assessment study. Journal of Cleaner Production. https://doi.org/10.1016/j.jclepro.2015.09.139
The British Museum Blog. 2020. https://blog.britishmuseum.org/everything-you-ever-wanted-to-know-about-the-great-court/
The History of the Mary Rose. (n.d.). https://maryrose.org/the-history-of-the-mary-rose/
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