Sustainability and renewability of Natural Resources

The growing importance of the consideration and use of sustainable materials depends on the relationship between the renewability of the natural resources and the material products that are generated from them. Renewable resources are considered to belong to the natural environment and are replaced by the natural processes that occur in that environment as part of an ecosystem. Non-renewable resources are natural resources that occur only in a fixed amount or are used up faster than nature can create and replenish them over geological time spans. The risk of depleting a natural resource can make their use less desirable when other, more sustainable, alternatives exist.


Artwork by Jan Hendrix; engineered and fabricated in mirror-polished aluminum by Zahner.
Artwork by Jan Hendrix; engineered and fabricated in mirror-polished aluminum by Zahner.

how are metals sourced?

Metals originate from the naturally occurring solid material, ore. Ore, specifically bauxite is extracted from the Earth’s crust through mining. Bauxite is an amorphous clay-like rock that is the primary commercial ore that makes up aluminum. It consists largely of hydrated alumina with varying proportions of iron oxides. From here, the bauxite is processed into alumina/aluminum. The fact that the ores are mined contributes to the misconception that it is a depletion of natural resources. However, metals such as aluminum (Al) and Iron (Fe) are elements and therefore cannot be destroyed or depleted. The Earth’s overall resource deposits of metallic elements have not decreased but simply change locations and present themselves in different forms. 

Specimen of bauxite
Specimen of bauxite

Metal is a permanently accessible material

Aluminum and steel have many product applications, and once these product applications cease to function in their useful existence, not material lifespan in the case of metals, the aluminum and steel can be recycled and reused in the creation of another product. This cycle allows the aluminum and steel to remain a permanently accessible material through recycling. Consequently, each time the aluminum or steel product is recycled into a new product, the properties of the metals are retained. As a result, this cycle can take place an infinite amount of time with little to no change to the inherent properties of the metal. 


Detail of Stainless Steel facade on the Nascar Hall of Fame.
Detail of Stainless Steel facade on the Nascar Hall of Fame.

METAL IS LIGHTWEIGHT, DURABLE AND LONG-LASTING

Metal also offers a lightweight, fire resistant, and durable alternative to wood and plastic material applications. Unlike wood, metal is not susceptible to rot, termites, or mold. A metal roof for instance, will last several times longer than a traditional asphalt roof. The roof on the Chrysler Building in New York is nearly 100 years old and has been cleaned only once. It should perform well for at least another century. Zinc roofs in Paris have held up since the Napoleonic era.

Detail of interference coated stainless steel in various color options on the Neiman Marcus flagship store.
Detail of interference coated stainless steel in various color options on the Neiman Marcus flagship store.

METAL SAVES MONEY BY REDUCING CONSTRUCTION WASTE

Constructing with metal comes with the advantage that the majority of fabrication and assembly has to be done off-site thus reducing on-site labor, cycle time, and construction waste. If the construction of a 2,000 square foot residence is framed in steel there will be less than 2% leftover material, all of which can be recycled. Compared to a house of the same square footage framed in wood, the waste generated would be close to 20%, and all of it would go to a landfill. 

Custom aluminum facade for Nike flagship store.
Custom aluminum facade for Nike flagship store.

Metal is a Cradle to cradle material

Cradle to cradle refers to an inclination in design standards to generate products and systems that model human industry on nature’s processes viewing materials as nutrients circulating in healthy, safe metabolisms. Metal fits these requirements in its various forms.


 No other material known to mankind can be used over and over to produce lasting utility. Not wood, glass, stone or ceramic. Metals, once they are captured from their mineral forms, can be repurposed indefinitely. - Bill Zahner, President & CEO, Zahner


SUSTAINABLE PROPERTIES OF steel

As far as building materials go, steel is one of the most sustainable. It is not only environmentally conscious but economically strategic in its inherent longevity and durability. Steel is the most recycled material in the world. More steel is recycled each year than aluminum, paper, glass and plastic combined. Steel is unlike wood and plastic because it is only used and never consumed. The process that takes place to create steel is arguably worth the energy required, because once the material is produced, it is reused infinitely, thus making it one of the only truly cradle to cradle materials. 

Solanum steel cladding the exterior of Arkansas House.
Solanum steel cladding the exterior of Arkansas House.
Light enters the space through the custom perforated steel for the Irving Courtyard screenwall at KCAI.
Light enters the space through the custom perforated steel for the Irving Courtyard screenwall at KCAI.

sustainable properties of aluminum

Aluminum is also considered one of the most efficient and sustainable materials. The process of melting Aluminum down to its molten form does not change any properties of the metal. Therefore, like steel, aluminum can be recycled infinitely. Aluminum is one of the most widely recycled materials and through the recycling process it saves 95% of the energy that it would cost to produce new aluminum.

Angel hair aluminum and stainless steel panels on the Fisher Center at Bard College
Angel hair aluminum and stainless steel panels on the Fisher Center at Bard College

SUSTAINABLE PROPERTIES OF copper

Like aluminum and steel, copper is 100% recyclable and there is no diminution in the integrity of the metal regardless of its state either as raw material or a manufactured product. By volume, copper is the third most recycled metal following steel and aluminum.

Copper screenwall for the National Museum for the American Indian in Washington D.C.
Copper screenwall for the National Museum for the American Indian in Washington D.C.
Interior copper panels for the Mitsitam Café in the Smithsonian.
Interior copper panels for the Mitsitam Café in the Smithsonian.

From a sustainability standpoint, metal is a clear choice for designers seeking a durable, long-lasting, and beautiful material option for facades, interior features and artwork. The myriad of benefits, including recuperation of cost once the material reaches its aesthetic lifespan, make metal one of the greenest options available in the marketplace today.