Rethink Zinc: An Eco-Friendly Architectural Metal
You may not immediately think of the word “sustainability” when considering metal as an exterior cladding material. This is in part due to the harmful processes by which metals are extracted, fabricated and then treated. This can lead to destruction of local ecology by extraction, factory emissions and byproducts and ultimately depending on the coatings, poor indoor air quality once installed. For example, some ferrous metals such as the always beautiful corten steel have adverse runoff effects into the local water and air supply. However, Zinc stands in a category all its own when considering its environmental impacts via extraction, production and implementation and is gaining popularity especially in the United States. Besides zinc’s beautiful and unique matte bluish-gray patina, if you’re thinking about using metal cladding for your next, or first, project here are a few reasons you may want to specify architectural zinc panels.
Zinc is the 23rd most abundant material in the earth’s crust. It is literally part of everything from rocks, water, air and is in every cell in all living organisms. It is also used in fertilizers to aid in plant yields. For humans, it is an essential nutrient. Along with a fairly natural cooperation with most of the planet, a global supply of zinc has been calculated to still be available for the next 750 years at the current extraction rate.
An irrefutable argument, that the very nature of extracting these types of slow-build resources is not a sustainable action, is true and is a tough argument. Therefore I will leave this one for the comments section below. However, if extraction is going to take place, and it will, the more minimal of an impact that process can have on the local ecology, the better. It is important then to compare processes on a level playing field, i.e.: the extraction and use of metals. This allows for relative comparisons and offers opportunity for competition and improvement. When viewed along its life cycle from extraction to use, zinc has a great track record, as an industry as well as a material, in playing well with the environment.
2.| Life Cycle Assessment
The Environmental Protection Agency uses life cycle assessments to gauge how a material, product, process or service impacts the environment. This includes the extraction process, any alloying processes or fabrication techniques. The EPA’s assessment and subsequent interpretation of any of these impacts helps inform designers, fabricators and the general public when making decisions. Zinc is highly regarded as a sustainable material when considering this assessment.
Starting with extraction, the “great” thing about zinc is that it is mined using an underground process rather than a strip mining process. This ensures at least a minimized local disruption. This does get points when considering the embodied energy of a material, or the sum of all the energy to produce a product or material. Fewer machines razing fewer acres not only saves energy, but valuable natural habitats. Zinc has the lowest embodied energy of all non-ferrous architectural metals.
The emissions of some factories that make architectural zinc, a more pure alloy with over 95% pure zinc, is water. When purified correctly this water can be made potable, thereby decreasing water consumption. This is actually the case in the RHEINZINK rolling mill in Datteln, a small town in Germany.
3.| No Paints, Sprays or Other Coatings Needed
Due to the natural, beautiful and inherently structural weathering of zinc, no coatings are needed to preserve it from corrosion. These are the natural, physical properties of a patina, a process called patination. Right out of the assembly line zinc has a shiny, silver appearance. But over time and depending on your region, normal or marine environment, it turns its distinctive bluish-gray. Certainly, this is a particular aesthetic, but in my last post on Natural Wood Siding, expressing the aging properties of materials lets the material be what it wants to be, and is also a sustainable act. Eliminating the need for coatings zinc reduces the potential for any volatile organic compounds (VOCs) to be applied by manufacturers and fabricators. This weathering process usually takes around 5 years. Another interesting fact about zinc it that due to the active and continuous restructuring of zinc due to the patination process, zinc is a self-healing material. Any scratches on the surface will eventually be covered up naturally under its own accord.
4.| Long Lasting
It is important to specify architectural grade zinc when working with an exterior application. This ensures a purity in the alloy that can give your cladding an endurance of up to 100 years. This not only means that there is a smaller extraction and fabrication turn around, but that its life cycle cost keeps more money in your wallet. By not having to replace, repaint or reapply protective coatings, zinc can end up being an economical as well as an environmental choice. It is also highly recyclable. Due to the purity of the alloy, 80% of the zinc available for recycling get recycled. That means that when sourcing materials for recycled content, zinc will most always make the list.
What do you think? How can we reduce our impact while we are on this planet, and make a better place for the coming generations? Do you buy that zinc is a sustainable process/material? If not, let me know why. I would love to hear your thoughts.
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