Metal Construction is the construction of buildings and infrastructure using metals as the sole building material. This means that all of the building framework including: beams, columns, and studs, are made of metal. The strength, durability, low maintenance, versatility in function, and low cost of metals make metal construction one of the best options for construction applications with about 40% of non-residential building being made of metal[1] . Steel is by far the most common metal used in metal construction due to its strong, adaptable, lightweight, and economic properties[2] . The construction industry uses about 583 million metric tons of steel, which makes up about 56% of the total amount of steel in production[3] .
Steel Building Framework

According to the ASCE, sustainability is: A set of environmental, economic and social conditions in which all of society has the capacity and opportunity to maintain and improve its quality of life indefinitely without degrading the quantity, quality or availability of natural, economic, and social resources.[4] There are three components that must be met for an item or process to be sustainable; it has to be economically viable, socially acceptable, and environmental friendly. Economically, for metal construction to be sustainable, it must produce enough income for metal and construction companies to support themselves and make a profit. Metal must also promote growth in the future. Sustainability in metal construction also includes being environmental friendly.The use of metal over other structural materials can benefit the environment by reducing the amount of toxins into the air that are released over time. For example, in an attempt to keep lumber from rotting, chemicals such as chromated copper arsenate and copper azole. Over time, these chemicals and preservatives get into the atmosphere and are harmful toward humans. By using metal, this problem is avoided, making it more environmental friendly[5] .
Steel Reclamation Center for Research Design
Steel Reclamation Center for Research Design
Within the metal construction facet of the industry, there is room for sustainability as the energy to produce steel is about 12% of the world's energy emissions.[6] The iron and steel production is also the highest emitter of carbon dioxide. Though steel manufacturers may not consume as much water as some other material manufacturers, they are still consuming about 400-500 liters of water per 1 kilogram of material weight.[6] There is not only room for improvement in sustainability in the construction phase of metal buildings, but also in the manufacturing stage. The construction industry can become environmentally sustainable and continue to grow and expand by being more careful with how the metal is used and how it is produced.


Metal Construction

Around 6000 B.C., man discovered the first metal: gold, and that he could shape and form it to create objects. Next, around 4200 B.C., copper was discovered, silver around 4000 B.C., and smelted Iron finally was discovered around 1500 B.C. It was Copper that was first shaped and formed into useful products like tools and weapons. Throughout the years man experimented with smelting copper with other elements to create a stronger material, but it was with the discovery of wrought iron that things changed. Wrought iron revolutionized man’s tools so
much that this period in time is now called the Iron Age.[7] Around the time of the Middle Ages with the development of the blast furnace,
people began to cast iron into shape. Men experimented with iron and its carbon content, in an effort to make it stronger, and steel finally came into the picture. Steel has higher carbon content, around 0.2-1.5%, making it stronger than wrought iron.[8]
Steel Production Process
Steel Production Process

It was not until the mid-1800's that metal began to be used in the structural framework of buildings. By the late 1890’s, design and building technology for metal high-rise buildings had developed common construction practices such as bolted or riveted I-beam frames as well as portal wind bracing. With the onset of the Great Depression, the construction of high-rises ceased. It was not until after World War 2 that metal structures were once again being built.[9] During this construction boom, metal construction was mostly prefabricated, but as better technology came around, metal construction began to have more versatility in design through engineering. Once computers began to come out they began to take over the analysis and design, leading to more variability and a make-to-order process.[10] From hammered iron tools to custom designed structures, man has learned a lot about how to use the earth’s metal resources.

Sustainability in metal construction became very important to mankind as it was determined that to build an average 2000 sq.-ft. home, it takes about 40 to 50 trees when using wood. When steel is used, the same structure can be constructed using the equivalent of only six recycled automobiles. To read more about the benefits of using steel visit: Sustainability: Steel Construction.

Construction Application

There is a wide variety of applications metal contributes to the construction world.[11] A common misconception is that metal construction is limited to large projects or buildings. However, metal construction is available for a wide range of projects such as:[12]
  • Structure: frame and metal floor decking
  • Envelope: roofing and wall cladding
  • Substructures: foundations and sheet piling
  • Internal fit-out: wall partitions and service ducting
  • Modular and panelized systems
  • Furnishings, fittings and finishes.


Sustainability is an important concept because its main goal is to create a world that future generations can live in comfortably and further develop.[13] As the world’s population increases and we continue to advance in technology and improve the standard of living we put an ever increasing demand on the environment and its resources. The earth cannot withstand the current rate of production and growth and sustainable practices should be conducted to help save the environment and resources for the future.[14]

Sustainability in the Industry

The construction industry sees sustainability as an adage to the practices that have already been set. For example, it is very common to see people in the construction industry only incorporating sustainable practices if it will be free of cost. Companies lack a motive for pursuing sustainable processes unless they are forced to by enforcement or fines.[15] There are several corporations that are trying to bring about a fundamental change to the construction industry by incorporating sustainability into the construction process. Some of these corporations include: USGBC (LEED) the ASCE, along with private firms.

At the moment, one of the ways that the metal construction industry is creating a sustainable environment is by using recycled material and by recycling leftover and scrap metals. Another way that the construction industry is becoming more sustainable is by choosing materials that are more energy efficient, for example there are certain metal roofs that through reflective properties can reduce energy consumption.[16] Another good way that engineers and the construction industry improve the sustainability of metal construction is by building a quality and long lasting structure that can have a long life and many purposes, since a lot of the sustainability issues arise when new products are made. The USBGC, through LEED, and the ASCE also offer incentives for building a sustainable design. These organizations have set up easy to follow, step-by-step plans on how to build a more sustainable building by choosing more efficient materials, such as steel. Though the initial investment might be slightly higher, the overall savings during the building's lifetime more than makes up for it.[17]

Metal construction could improve its sustainability drastically if the industry would look beyond the construction process and begin to identify areas of improvement from the source of the material. Much of the waste generated in the field of metal construction is happening during the production of metal, especially steel. About 104 billion metric tons of steel is produced; 928 million metric tons of it comes from the ore, while 568 million metric tons of it comes from scrap.[18] Metal manufacturing takes about 6% of the total energy used by manufacturing in the U.S.[19] With such a wide industry, there is room for material efficiency throughout the production process and beyond.
Steel Recycle Life Cycle
Steel Recycle Life Cycle

Material Efficiency

About 20% of the energy used during steel production is consumed during the extraction and refining phase. One way that sustainability could be promoted in this process is by bringing in new process routes such as the Fray process, with titanium.[20] In the titanium extracting phase, there have been advances made in which the ore is taken out, increasing the yield,making the process far more efficient. This lowers the costs of production, including those of energy.[21] Then comes the production phase; in this phase, efficiency can really only come through radical change. Some ideas that have been suggested, for the reduction of energy, is by going with deformation instead of casting. The energy used for deformation is less than for casting and fewer martial is lost during the deformation process. The problem with this is that deformation cannot create the complex shapes that casting can. Another option would be additive formation. With this method the metal is shaped by using electro- or vapor- forming through masks, direct bonding of the powder through selected laser sintering, adhesive bonding, or super-sonic compaction. Another engineered solution would be through creating a way that metal type and grade can be recognized even after being shredded; part of the success of recycling comes from proper recognition of the material. By using some sort of internal identifier, such as nano-scale magnetic particles, a recycling plant could quickly and efficiently identify the type of metal as well as its grade. This saves time, money, and most importantly energy consumption. Better recycling practices can lead to more material without having to extract and refine more. Engineers can also help with material efficiency by engineering products that would require less of the material or would have a longer life span.[22] There has been a wave, in the past ten or so years, of new regulations to increase sustainability in the construction field. Many of these regulations deal with pollutant emissions, water regulation, and recycling (the use of recycled materials and practice of recycling on the construction site).[23] Though legislation and regulations are seen as a hassle, they can help bring awareness that if taken up by the leaders of the industry can bring beneficial change. Through engineered, legislated, or socially imposed changes in the production and processing of metal, the material efficiency of metal can be greatly improved to the point of increasing its sustainability factor.

Material efficiency also has its challenges. These challenges come in the form of technological barriers, economic and business challenges, regulation and legal challenges, as well as social challenges. Some of the technical barriers are that most products are not made to be easily disassembled. There is also no set monitoring program or method to test the condition of a structural member for reuse. The reuse of structural members is also discouraged because there is no real market for it as there is a high amount of new or recycled material already in the market. Another factor against material efficiency are the production companies and the economic system as they encourage growth and new products to replace the old ones; a long life is not desired business wise. There are also times when regulations and codes can work against sustainability by making it hard to be innovative with materials and the standards are written with new materials in mind not recycled. People’s consumerism is also a hindrance to sustainability as people do not like to cut down on their buying and demand for new products. There is also an attitude, in much of today’s culture, for convenience and getting things done quickly;[24] recycling takes extra time, thought, and effort to begin and maintain.

Looking to the Future


A way that metal construction can become more sustainable is through better recycling practices and higher awareness. Recycling is one of the easiest ways that sustainability can be achieved in metal construction. During construction, as the pieces are being placed and fit, a lot of waste is accumulated. Raising awareness and instructing the workers to recycle is an immediate action towards becoming more sustainable.[25]
Recycling as part of sustainability
Recycling as part of sustainability
. The reuse of metal is another practice that can increase the sustainability of metal construction. [26] To help improve re-usability engineers and designers can design buildings to be more easily taken apart, collected, and used at another site, for example by designing bolted connection instead of having them welded.[27] If metal construction became more prefabricated, not only would designs be more similar and more interchangeable or reusable, but they could also be designed and built with more adaptability.[28] This adaptability can lead to an extent of the building’s life span. Off-site fabrication and construction is more controlled and leads to fewer waste and less defects.[29] Improving the overall system for material reuse so that reusing doesn’t have to be more expensive than buying new or recycled. For example, an organization in Glasgow was offered one of the roofs from the London Olympic buildings, but because of how much it would take to transport the roof it ended up being cheaper to buy a new roof.[30] There is currently no practice for the testing of reused materials to see in what condition they are in, so people decide to go with the new material, making the recycled material basically go to waste.[31] Through better on-site practices and awareness, as well as improving the system for the recycling of metal construction materials, sustainability can be improved in the future.

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