Bicycle helmets are products that serve one purpose: to protect your head from any oncoming accidents while on your bike. However, have you ever stopped to think what goes into your helmet? In the lifecycle of a bicycle helmet, there are many raw materials that go into their creation. The manufacturer’s choices of materials will determine the material’s paths; including where these materials come from, their manufacturing processes, how long they retain functionality within the product, and where they end up.
The raw materials that go in the helmet are plentiful, including many raw materials made to create secondary raw materials that are actually used in making the helmet, such as EPS foam. One of the main components of the helmet is the liners. The liners of a helmet normally contain EPS foam, or expanded polystyrene foam ("How Bicycle Helmets Are Made"). EPS, in turn, is made from styrene, also known as ethylbenzene. Styrene is “a colorless, oily liquid” which occurs naturally in plants like peanuts and coffee beans (U.S. Department of Energy) (“The Safety of Styrene"). However, the production of styrene is quite different, as they form the ethylbenzene compound by combining ethylene and benzene through a chemical reaction using a catalyst like aluminum chloride. Benzene and Ethylene are parts of crude oil, like petroleum or coal, and normally come from petrochemical industries such as oil refineries. Once combined into ethylbenzene, they will transform it into styrene by either using heat or an initiator of the reaction in order to dehydrate it into styrene. Finally, with the styrene, you can create the polystyrene beads through a polymerization process where “tiny drops of the monomer (in this case, styrene) are completely surrounded by water and a mucilaginous substance. Supporting and surrounding the styrene globules, the suspension agent produces uniform droplets of polystyrene” (How Products Are Made). Once the polymerization is finished, the beads are washed and dried, ready to be sent to helmet manufacturers who produce the EPS foam (How Products Are Made).
Within the liners are also interior reinforcements to reinforce the EPS foam, which are also formed using secondary raw materials. It is normally buried within the EPS foam and unknown by the public how they integrate it within the mold for the EPS foam. However, it is known that this reinforcement is made either of nylon, polypropylene, or metal (, although the type of metal is unknown). Even so, nylon and polypropylene are both secondary raw materials used for the reinforcement for the EPS foam and the ribbons that are later sewn together to create the straps of the helmet ("How Bicycle Helmets Are Made"). Nylon is a polymer that is formed using adipic acid and hexamethylenediamine. Adipic acid is made from ketone-alcohol oil and “is oxidized using nitric acid to produce adipic acid” (The Chemical Company). Hexamethylenediamine is made from hydrogenation of adiponitrile, an organic compound made from more hydrogenation of butadiene, using nickel as a catalyst (Corn). Essentially, these materials originated within petrochemical industries, and undergo many processes before reaching their aimed product (AOGHS). In order to create nylon, the adipic acid and hexamethylenediamine combine through condensation polymerization, where the water is taken out and a chain of the polymer is created. The sheet/ribbon of nylon is then taken and cut into chips to either mold or melt and pull it through a spinneret turning it into stringed nylon (Woodford).
Polypropylene, however, goes through a different process than nylon does. It’s made from propene, which can come from gas oil or propane from the petrochemical industries too. It can be made using Ziegler-Natta catalysts, which they add “titanium(IV) chloride and an aluminium alkyl, such as triethyl aluminium” (Poly(propene)…). The propene undergoes two processes, the bulk process and the gas process. The bulk process involves polymerization of propene, which includes heating to “a temperature of 340-360 K and pressures of 30-40 atm… …After polymerization, solid polymer particles are separated from liquid propene, which is then recycled” (Poly(propene)…). After the polymerization, it goes through the gas process where “A mixture of propene and hydrogen is passed over a bed containing the Ziegler-Natta catalyst at temperatures of 320-360 K and a pressure of 8-35 atm” (Poly(propene)…). After this, the resulting product of the refined polypropylene, ready to be turned into polypropylene fibers or molded.
The shell of the helmet is another part in which uses a secondary raw material: PET plastic. PET is short for polyethylene terephthalate, otherwise known as polyester. PET is made from materials in crude oil and gas (PET Resin Association). Ethylene glycol and terephthalic acid, which are both raw materials, are both materials from there as well, used in order to create PET (PETRA). Ethylene glycol is made through ethylene oxide, in which it reacts to water through an acid based catalyst. Terephthalic acid is made when combining paraxylene, which is a product from petroleum, and acetic acid, otherwise known as vinegar (Hitachi). So, after all of these raw materials have been prepared to create the Ethylene glycol and terephthalic acid, they combine them to create PET pellets, which then are heated to form thin PET sheets, which will soon be ready to go through helmet processing (PETRA).
After being able to acquire the materials to make a helmet, there are several processes that go into manufacturing the helmet as well as other materials. Typically, helmets are created starting from the outer shell, so you begin with a sheet of PET plastic. With this, helmet manufacturers first come up with a design, done by hand or computer aided, in which they add color to a designed template, and allow them to dry (How It’s Made). Unfortunately, I was unable to discover a source of what type of paint/ink they use for the bicycle helmets; however, the paint must be compatible with the plastic so that it would not eat away it ("Painting a Bicycle Helmet"). After they print out the complete sheet, the helmet must be molded. To mold, the printed PET sheet is placed in a heat former and then heated to help it form into the shape of the mold. When the shells are cooled, they cut them into their helmet shapes using machinery, leaving the end product of the helmet shell with trimmed ventilation openings to be later attached with the lining. Next is the preparation for creating the EPS foam for the helmet. The polystyrene beads must first be fluffed up in order to expand themselves before being placed in the mold for the liner. Afterwards, the PET shell, the inside lined with glue, and now expanded polystyrene beads get baked together in the helmet mold (along with any potential interior reinforcement), becoming a proper helmet (“How It’s Made Bicycle Helmet”). Not all helmets are made this way since liners can be attached to the shell without the use of glue, but I was unable to find anything about this process. The glue that manufacturers most likely use though, and recommend to others, is called 3M Super 78 adhesive, which is a spray/aerosol adhesive (“Bicycle Helmet Repairs”). Unfortunately, I couldn’t find the materials that go into this specific adhesive either, but I do know that it bonds polystyrene with other materials strongly, it is heat resistant, and it won’t degrade EPS or polystyrene in general (Menards). After attaching the liner to the shell, the straps must be added to complete it. Generally they use either nylon of polypropylene for this material, and in the video they specifically mentioned the process for nylon ("How Bicycle Helmets Are Made"). The straps in this process are sewn together through a machine and then experts assemble the straps to accommodate for the different size heads (How It’s Made Bicycle Helmet). Then they begin to cut out foam padding for size and comfortability adjustments. This padding is created from ultracel foam, made from “BiOH polyols, a soybean derivative” in which is created by placing soybean oil through a carbon filter (Best Deals) (Simplicity Sofas). After cutting the pieces of padding for these helmets, they are placed inside the helmet using Velcro. Velcro is created form nylon and polyester, and so they attach it to the adjustment pads and the inside of the helmet (“Velcro Fasteners…”). Then all that’s needed is to insert the straps, and the helmet is ready to be sold and used (“How it’s Made Bicycle helmets”).
After building the helmets, they must be transported and distributed to consumers of the product. The focus is not only upon the transportation of the helmets, but the raw materials to create them too. Much of the raw materials to create helmets come internationally, and after doing a quick google search I’ve found only sites and areas of mainly China and India being the suppliers and sellers of these raw materials. International trading is most likely done using ships, as it cuts freight costs although ships normally run on engine oil/bunker fuel (International Chamber of Shipping). This type of fuel is “a type of liquid fuel which is fractionally distilled from crude oil” (McMahon). It is also one the densest fuels around, and has been known to create oil spills (McMahon). Other methods of transportation may include commercial trucks and freight trains. Both use up diesel fuel, but trains are a lot more efficient (CSX Corporation Inc.). Diesel fuel is described to be “a mixture of hydrocarbons obtained by distillation of crude oil” (Majewski). The fuel grades may also be different depending on what countries they come from (Majewski).
When it comes to use, reuse, and maintenance of a helmet, there are not many materials that are involved with or in maintaining it. Maintaining the helmet is fairly simple, and there are certain parts that are replaceable including the adjustment foam pads and Velcro on the inside. The buckles of the straps in the helmet can be replaced too. With the straps, you may be able to contact the manufacturer to have them fix it, but it may be unlikely this will happen. However, certain parts, if cracked or broken, will render your helmet as unusable. These breakages include cracks within the liner, shell, and broken straps (“Bicycle Helmet Repairs”). With a broken helmet, you can disassemble it so that you can reuse parts, such as the EPS foam as soil for potted plants or just use the entire helmet as a pot itself. Other than that, there aren’t methods that need extra materials added for the helmet.
Maintaining helmets is quite different from recycling them, as recycling helmets do require extra processes and treatments. PET plastic of the helmet can be recycled; however, you must make sure it is PET and not some other type of plastic, as it is uncertain that it can be recycled. PET plastic does go through a process of cleaning using extra materials such as a “special detergents” (Hurd). Once cleaned and processed, the PET can be used as raw material once again (Hurd). EPS foam can be reused and recycled too. It also must be cleaned and processed, in order to sell as raw material back to manufacturers. I was unable to find what cleaning materials in specific they use, but the process is simple. After cleaning, they heat the EPS in order to shape them back into pellets so that manufacturers can process them into products once again (Kelly). The rest of the materials, including the straps and buckle, are normally dumped. I was unable to unearth the information on how they treat dumped materials of these kinds.
Through researching the life cycle of a bicycle helmet, there are tons of raw materials used and created in making, treating, transporting, and disposing it. Many of these raw materials are derived from fossil fuels, if not all. Luckily, there is no one way to create a bicycle helmet, though the methods and materials I have mentioned are just how it is done in general. Several other potential materials included: Expanded PolyPropylene (EPP) foam, Expanded PolyUrethane (EPU) foam, Expanded Polylactic Acid (E-PLA),and Cellufoam. All these foams were other potential foams used in bicycle helmet liner. Tape, specifically 3M 471 tape, was also another potential helmet material, although it is not always used. If I had to mention all the ways in which these materials were processed and created, this paper would be much too long. There would be many processes that I would need to include and research too. However, these many different ways show that there are many different designs and ideas that go into the lifecycles of these helmets. Although helmets are troublesome when it comes to the environment, it shows there are ways in which we could someday make helmets environmentally friendly (“Can I Recycle My Bicycle Helmet?”).
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"Bicycle Helmet Repairs." Helmets.org. Helmets.org, 19 Mar. 2015. Web. 13 Mar. 2016. <http://www.bhsi.org/repairs.htm>.
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Hitachi, Ltd. "Production Process for Purified Terephthalic Acid (PTA)." Hitachi: Inspire the next. Hitachi, Ltd, 2016. Web. 12 Mar. 2016. <http://www.hitachi.com/businesses/infrastructure/product_site/ip/process/pta.html>.
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Hurd, David J. "Best Practices and Industry Standards in PET Plastic Recycling." Best Practices and Industry Standards in PET Plastic Recycling (n.d.): n. pag. David J. Hurd,. Web. 13 Mar. 2016. <http://www.napcor.com/pdf/Master.pdf>.
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14 March 2016
Energy in the Life Cycle of Bicycle Helmets
The expanding cultural involvement with outdoor sports and activities including bicycling, skiing, snowboarding, skateboarding, and roller-skating, has associatively accumulated increasing reports for head injuries. Bicyclists have the highest statistics of individuals who have experienced some form of head injures (“Helmet Related Statistics”). In response, the necessity for protective gears, such as shock-absorbing helmets, have become a part of the economical and manufactural trend, requiring the extraction of raw materials and varying forms of energy to produce an equipment that would sufficiently protect the user. The production rate of bicycle helmets from the United States, alone has exceeded four million in one year (“Helmet Related Statistics”). Interestingly, despite its distribution rate, only eighteen percent of bicyclists and bicycle helmet consumers were observed to have appropriately used the equipment (Moore, “Protective Helmet”). The life cycle of bicycle helmets entails a wide range of energy input throughout its manufacturing process, especially in gathering and creating the bicycle materials. It is, therefore, important to be informed and aware of these various energy-related systems and generate a perspective of the sustainability level bicycle helmets have within our progressing society.
With the progression of a quickly developing culture and society, ideas are constantly implemented yielding further innovations being cultivated and more resources sought upon to accommodate these contemporary needs and demands. Whether a design is sustainable or not, is dependent on the type of materials, forms of energy consumption, the recyclability of the design, and to some extent, the demands of the product. In Kuhlman’s article he defines sustainability as “never harvesting more than what the forest yields in new growth” (Kuhlman). In addition, it is essential to consider a design’s usability to quantitative distribution ratio. Because designs primarily require the exploitation of fossil fuels, which are inherently unsustainable, an unused product that is abandoned to pile up in storage does not necessarily contribute to its overall sustainability to the evolving environment. Bicycle helmets require a massive amount of energy input towards its mass production, however, only a small portion of the consumers properly use their helmets to its maximum capacity (“Helmet Related Statistics”). The ratio between the deficiency in bicycle helmet use to the high product distribution has, therefore, prompted the inquiry of its economical and environmental sustainability.
Energy is an essential element used to perform work. Throughout the life cycle of bicycle helmets, energy is existent and expended in the process of gathering raw materials and during the formulating, assembling, distributing, and recycling procedures. Some fundamental forms of energy are derived from raw fuels such as petroleum, coal, wood, and manpower. In conversion, these raw sources of fossil fuels are combined and exploited to generate secondary forms of energy, which are then utilized within the industrial regions of manufacturing companies. Typically, these secondary forms of energy systems include electrical, thermal, chemical, and mechanical energy (“Energy Facts”). Industrial machineries and technological apparatuses are responsible for harnessing and utilizing these energy systems to cultivate work. In most energy-related systems today, the universal mode of energy commonly known is electricity. Although electricity seemingly functions as an independent extraction of energy, it realistically requires a large use of fossil fuels, such as coal, to generate the proper amount of kinetic energy to manifest it (Woodford). The significance in being educated about the methods and ingredients used to generate energy for the development of a design may clarify the product’s level of sustainability.
Bicycle helmets are generally made up of three major parts. The exterior shell is molded from polyethylene terephthalate (PET), the interior lining is constructed with expanded polystrene (EPS) foam, and the strap is made of nylon (“How Bicycle Helmets Are Made”). Each of these major raw materials requires the largest sum of energy input and mechanical procedures to process and shape them into the common bicycle helmet.
The exterior shell of bicycle helmets is primarily made by chemically and physically engineering a synthetic plastic material called polyethylene terephthalate (PET). PET plastic is a secondary raw material made up of synthetic polymers, commonly used for the ordinary plastic water bottle. Manufacturers chemically synthesize ethylene glycol and terephthalic acid, two primary raw materials, by exposing them to very high temperatures and very low pressures. Once the chemical process is done, polymer chains of PET are created and spliced into smaller particles. Another thermal process is subsequently required to expand and stretch the PET particles into a thin sheet of plastic for manufactural use (“About PET”). Bicycle companies, such as MET, often import PET plastic sheets for the use of the outer bicycle helmet shells. Routinely, these plastic sheets are placed into machines that uses heat and a bicycle helmet mold to shape it into its proper form. Successively, a calibrated robotic machinery trims and removes the unnecessary leftovers of the plastic (Cole). The overall manufacturing process of bicycle helmet shells demands for a consistent integration of chemical and thermal energy systems to construct the PET plastic material. In addition, manufacturing companies are anticipated to necessitate a considerably large amount of electricity to operate, which consequently requires greater input of coal-powered energy systems, generated from electric power plants. Nonetheless, PET plastic is a recyclable material that can be reused in making other plastic materials by reapplying heat to alter its shape and physical state (“Sustainability”).
Foam liners are a durable and cheaply made, but initially undergoes a series of physical and chemical energy systems prior to being casted into the shape of a helmet. The interior foam liners are a vital and crucial part of a properly functioning bicycle helmet. It provides the protection of a potential impact and head injury (“Bicycle Helmet Liners”). Commonly, the foam liners are made of expanded polystyrene, which is a thick foam lining on the interior enabling the helmet to be more shock absorbent. EPS is a secondary raw material specifically derived from the chemical extraction of styrene, a primary organic compound that is commonly found in plants. The initial process of obtaining styrene requires the chemical procedure of exploiting petroleum and thermal energy (“It All Begins With Styrene”). Styrene undergoes several chemical and thermal energy processes that requires it to be isolated and is sequentially dehydrated until it forms into grain-like particles. From this physical state, styrene is deposited into a machine and exposed to high temperatures above 200 degrees Fahrenheit. Thermal energy is used to expand the grain-like styrene into larger beads, called polystyrene. Filters are used to partition the varying sizes and maintain a consistent sized bead (“How Is EPS Manufactured?”). Once the polystyrene beads are materialized, these larger beads are placed into a helmet-shaped mold. While capsulated and insulated within the mold of the machine, additional heat is applied and the beads pressurize and solidify into a sturdy blocky shape (“Bicycle Helmet Liners”). Evidently, cultivating the necessary ingredients to manufacture the foam lining involves an extensive systematic approach, such as the sequential phases in gathering and processing the primary raw materials into EPS foam.
Nylon straps are a secondary synthetic raw material created from the process of chemical and physical energy systems. The primary raw materials of nylon are organic chemicals found in fossil fuels, such as coal and petroleum. At moderate temperature and pressure, two large organic chemical compounds, adipic acid and hexamethylenediamene, are combined to react in a large insulated apparatus, known as an autoclave. As a result of the chemical reaction, a layer of fibrous nylon is yielded and subsequently melted with heat to be spun into fibrous yarn, which is common in clothing fabric and gears (Woodford). The consecutive approach to making the nylon straps is completed in a physical process called webbing. Webbing is the process of weaving together the fibrous nylon threads into a wider and strap-like sheet (“How Webbing Is Made”). Because nylon is primarily made of coal derivatives and requires a large amount of energy input to manufacture, it is apparent that it is not entirely sustainable.
Following the development of the exterior shell, foam liners, and nylon straps, humans become the prime movers who manually assemble the pieces. The assembling process is often accomplished through manual labor due to economical intentions. Each piece is fixed to one another, generally using adhesives. In addition, stickers, tags, and labels are added onto the helmet for aesthetics and merchandising (“How Bicycle Helmets Are Made”). Once assembled, bicycle helmets are selected to be tested for their overall durability and effectiveness. For example, MET tests their bicycle helmets by applying several damaging crashes and impacts onto each helmet (Cole). The overall energy input in assembling and testing is predominantly human powered and labor intensive.
In the research process, there was deficient information discussing the approach of distributing bicycle helmets. Although there are no definite sources that explain the specific transportation and distribution processes, bicycle helmets were presumed to be boxed and shipped to a wide range of retailers and warehouses either by plane or by large trucks (“How Bicycle Helmets Are Made”). Conclusively, these transportation systems require a large quantity of energy derived from fossil fuels, including gasoline and diesel for operating the locomotive engines.
Furthermore, recycling bicycle helmets is a complicated process because it is comprised of multiple parts that require different disposal treatments. It is not environmentally friendly to toss the entire helmet into the landfill since each part is recyclable. An encouraged solution is to carefully separate the plastic shell, foam lining, and nylon straps and recycle each independently (“Can I Recycle My Bicycle Helmet?”). Regardless of the procedure, dismantling a bicycle helmet will require further input of human-powered energy and electricity-powered machineries.
In studying the energy inputs and systems integrated throughout the life cycle of bicycle helmets, the idea of its sustainability level is debatable. The popular visible forms of energy systems in this life cycle include chemical, thermal, and electrical. Machines are a major prime mover in the developmental processes for the extracting and synthesizing every material. Generally, machines harness electrical energy to operate, therefore, manufacturing companies indirectly exploit fossil fuels, such as coal and petroleum (Woodford). Additionally, with the previous statistical knowledge of the distribution rate of bicycle helmets, approximately four million annually in the US, to the serious use of the product, being only eighteen percent, the consequences of depleting fossil fuels and adding to the landfill is relatively evident. Despite the possibilities in recycling the individual parts, the constant demand for fossil fuels for powering manufacturing companies to synthesize and distribute materials remain problematic in this scenario. The idea that bicycle helmets are unsustainable in the current society is distinct and apparent through the discoveries of the total energy consumption required during its life cycle and its overall extent of usage.
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