Design Life-Cycle

Caleb Deguire

Professor Cogdell

3/12/2026

DES 40A

Smoke Detector Life Cycle Analysis

A smoke detector is a device that has revolutionized home security against fire borne threats that otherwise would be missable and could be far more deadly to the average person. However these smoke detectors didn’t just show up overnight and were engineered over many years and their body took many steps to fully come into the form we all know it as. Because of how unique the smoke detector’s job is it relies on more advanced techniques and complicated resources than the average home-security device, not only this, millions are made and necessary to keep all the homes around the world safe because of this the supply chain to get all of them made is extensive. In this essay we will be breaking down the integral parts inside of a smoke detector and the intricacies that go into gathering the raw materials, processing them into a more usable form, assembling them into the smoke detector we all know, and lastly what the death of a smoke detector really means and how the parts inside are recycled, wasted, and lost to the processes.

A smoke detector is made primarily up of 4 primary components, these components are as follows, the plastic body, the circuit board, piezoelectric horn, and the ionization chamber. All these components come together to make your average ionization smoke detector, they work by first ionizing the air in the ionization chamber by using the alpha particles emitted from the americium-241, this creates a flow of positively and negatively charged ions that creates a flow of energy. This is what is considered a resting smoke detector, however once smoke breaks through this and disrupts the energy flow the alarm immediately sounds alerting the house and its residents of the danger. Now that you understand the core basics of how a finished smoke detector operates, let's dissect where the materials come from to be able to produce one.

However these primary components don’t just form themselves and they require substantial developments to actually get started on making your first smoke detector, so let's start out with breaking down the fundamental ingredients that go into making each primary component. Starting with the most crucial is of course the body of the smoke detector made out of plastic, everyone knows or has seen plastic before in their life but the steps to actually form plastic are incredibly convoluted. First to begin we need to get crude oil extracted from the ground. Crude oil originates from fossils that have been in the ground for millions of years that with the right pressure and heat broke down into the crude oil that we will be extracting. This oil on its own is a gold mine and has many different chemicals in it but to get what we need we need to slice out a specific layer, Naphtha. To do this we start out with heating the oil in a large furnace, after it has reached a sufficient heat we transfer it directly into the distillery. Inside of the distillery is where the crude oil is separated into different fractions, this is where we will be extracting our Naphtha. With our Naphtha in hand we begin our third process called polymerization, which is where the monomers we received from distilling are transformed into hydrocarbons that are higher in atomic weight than their counterparts. However in this process there are two different routes our monomers can take to become hydrocarbons. We can either use additional polymerisation where by adding a catalyst the reaction slowly turns the monomers by making them connect to each other in a loop where they all connect in the end. Alternatively, we can use Condensation polymerisation where it's more hands on and you treat it like building on top of each monomer. Lastly is the compounding step, which is the step where finally all our monomers become plastic, by mixing together all of our various blends of materials and heating the mixture to a melt, oil distillation and extraction researched by Baheti, Payal. Afterwards, we finally end up with plastic that we can use to shape our parts. Now that we have our plastic, let's focus on how to form this, the main way we are going to start forming it is plastic injection. Plastic injection is the process of putting our melted plastic into a pre-made mold of the shape we need. The reason this is the best for smoke detectors is because of the vast amount of smoke detectors we need to have them properly placed in every house. As well, plastic injection allows mass production far easier than alternatives, as shown by Nichols, Jeff . 

Now that we have our casing lets start focusing on the inside components, namely the circuit board that controls all of our separate components. The circuit board is derived from two primary materials: copper and fiberglass. While copper may seem easy enough to get most copper ore mined is only 1%> copper, so to get a mass of the stuff we need to start with open-pit mining like done in Ohio. Depending on which ore you find, Oxide or Sulfide the branch switches vastly so for simplicity we will be primarily focusing on Sulfide due to it being the most prominent source of copper worldwide. Now don’t less this confuse you, there is more oxide copper and it's closer to the surface but it is less concentrated with copper and is considered lower grade. The primary way to process sulfide copper ore is via pyrometallurgy, this is the process of 4 steps. Step 1 is froth flotation, in froth flotation the copper ore is crushed into a fine slurry and is added into a large vat of water. This is done because while yes we have copper we now have a plethora of useless rocks that we don’t want to waste time on, thus we drop in chemical reagents called “collectors”. Collectors are incredibly useful because they make the copper inside of the water hydrophobic allowing air to be passed through the vat and all the copper to rise to the surface while the useless rock is discarded. Now that we have our copper separated from the stone we need to clean it off, the second step is called the Thickening stage. In stage 2 we drop in our chemical froth of copper and “collectors”  in large tanks called “thickeners”. Inside the tanks the bubbles from the first stage break apart and the water is filtered out, thankfully this water can be reused in the first stage to help save on costs. Afterwards we take this copper and combine it with a 3-7 ratio of other metals and it goes into a smelter in stage 3, the Smelting stage. It's heated to 2300F where it will stay till it becomes liquid metal at which point it is dropped into a slag-settling furnace. Inside the slag-settling furnace the compounds end up producing a mixture of copper,sulfur, and iron with a by-product of slag. Now since we only need copper we are going to blast this mixture in a special furnace called a “Converter”. This copper sheet is 98% copper almost perfect, next it is taken to an “Anode smelter” which is used to burn off the oxygen on the copper and finally it is poured out into casts. These casts are 99% pure copper, but we specifically want copper cathodes so we drop them into a tank filled  with an electrolyte solution. After waiting 14 days for the plates in the mixture they are finally ready to be used in our circuit boards. We are almost ready to start processing and producing circuit boards but now we need fiberglass, specifically we need FR4 Epoxy fiberglass boards. It all starts with melting glass and taking the fibers and cooling them, we do this to make clear filaments. Once we have procured a steady supply we begin making fabric out of them; this is a delicate process that factory lines have to perfect. Afterwards we begin the impregnation step where the fibers are passed through epoxy, finally we are ready to cure them in a temperature controlled machine to properly cure them. Once done we repeat these steps to ensure they are ready for use, lastly we flatten them down multiple times to ensure they are perfectly smooth for wiring. Now with our  copper and fiberglass we can begin construction of our circuit boards, copper processing steps learned from ‌ The University of Arizona and FR4 production by Jhd-Material.com.

After our circuit board is completed we can move onto our second to last step and the most crucial the Ionization chamber, the ionization chamber is actually pretty basic being composed of two metal plates with one of them having a hole where the Americium source releases alpha particles to make a flow of both positive and negatively charged ions. This process is what causes smoke detectors to actually be able to detect smoke because the smoke disrupts this flow of energy and causes the horn to sound. To actually make this, we will use copper, thankfully since we already discussed the production of copper we will be continuing using that information. The copper acts as a pad that keeps the connection going but the main source of the connection is the Americium 241 to generate our alpha particles. Americium 241 is a man-made element that originates from Uranium 238, uranium 238 is an ore and similar to copper is often mined through open pit quarries. The uranium after being mined is then milled and crushed, afterwards it is transferred into tanks filled with sulphuric acid. After the uranium has been thoroughly dissolved it can then be  recovered. This uranium can then be used in reactors and over the life of the uranium 238 it breaks down into plutonium 238, repeating this process but instead with our plutonium 238 finally gives us our Americium 241 source that we need to continue on to the next step of the smoke detector, information provided by US EPA. 

The last core ingredient is our piezoelectric horn, which is made out of piezoelectric ceramic elements. These elements are crucial to the horn because of how they can transform the energy waves into sound allowing the alarm to work. However to actually make the piezoelectric ceramic element we need PZT (lead zirconate titanate), “PZT is made by mixing high purity lead oxide, zirconium oxide, and titanium oxide powders. After thoroughly mixing the powder goes into a furnace and calcined at 800C~1000C finally forming the ceramic material”, as shown by Yujie Technology Ltd. This finally gives us our PZT which now is as easy as putting the ceramic element between two pieces of metal and you have your piezoelectric horn. With this complete we are ready to assemble our smoke detectors.

Finally with all of our constructed components we can begin the engineering of our smoke detectors, this process is fairly easy since we already beat through the chaos making our building pieces. The main components missing for the final construction are screws to nestle all of our components together. The screws are made from steel which is a basic alloy of iron and coal which are then pressed into bars and then  finely cut into the screw sizes we need. After they are cut we cut off any residue and then press one side to create a head. After repeated pressing we’ve formed the basis of our screw and now we trim the length end to the threading we need and add a point with the press, this completes the screws and allows us to assemble our smoke detector to its fullest, screw making process from ‌Pinchback, Joseph. With our finalized smoke detectors we can begin shipping them out where we meet our last obstacle to finally providing smoke detectors around the world, packaging. With all our finally crafted mechanisms they need a box to ensure their safe arrival, for this we will use cardboard. Cardboard is made out of wood fibers, these wood fibers are most commonly harvested from pine, fir, and spruce interestingly. With our wood fibers we process them till they become a pulp of wooden fibers, then we dry them until finally flattening them into our beloved paper. Afterwards the paper is combined with other paper in a corrugation machine that utilizes hot steam to make flutes. Once combined and cut the cardboard boxes are ready for use and we can start packaging our smoke detectors to be shipped around the world, the box making process shown by “The Box Manufacturing Process Explained.”. While the shipping process is simple the energy cost that goes into moving all of them around the world is considerably high.

Once our product finally reaches the customer there is one core item every smoke detector needs to function, a battery. While batteries don’t often come with smoke detectors they are vital to the performance of a smoke detector. Thankfully batteries are a very easy commodity to source and can be bought from most stores and used for a large amount of time. Besides this the only other resources needed to keep a smoke detector running is the americium inside to keep the chamber from failing but as stated earlier the half-life is incredibly long. Because of how long the half-life is realistically it's not needed to be accounted for in the process. Because of Americium’s non-radioactive nature the disposal of the smoke detectors is actually quite simple, once the detector is done and it's time to replace it simply throw it away in your waste bin and you’re done they are off to the waste yard where they’ll stay.

Work cited

definitionconsulting. “The Box Manufacturing Process Explained.” Ribble, 22 Jan. 2018, ribble-pack.co.uk/blog/box-manufacturing-process.

‌Pinchback, Joseph. “How Is a Screw Made? Step-By-Step Process with Photos.” Wilson-Garner, 26 Sept. 2023, wilsongarner.com/how-is-a-screw-made/.

‌Eason, Eric. “Americium Smoke Detectors.” Stanford.edu, 16 Feb. 2011, large.stanford.edu/courses/2011/ph241/eason1/.

“PCB Manufacturing Process | Sierra Circuits.” Sierra Circuits, 21 Nov. 2024, www.protoexpress.com/kb/pcb-manufacturing-overview/.

Jhd-Material.com, 2020, www.jhd-material.com/knowledge/how-is-fr4-epoxy-fiberglass-board-made-. Accessed 12 Mar. 2026.

‌The University of Arizona. “Copper Mining and Processing: Processing Copper Ores.” Superfund Research Center, 13 July 2020, superfund.arizona.edu/resources/learning-modules-english/copper-mining-and-processing/processing-copper-ores.

“How Smoke Detector Is Made - Material, History, Used, Parts, Components, Steps, Product, Machine, History.” Www.madehow.com, www.madehow.com/Volume-2/Smoke-Detector.html.

team, Flora. “Everything You Need to Know about Piezo Speakers.” Flora, 19 May 2023, flora.tech/everything-you-need-to-know-about-piezo-speakers/.

Hidayat, Darmawan, et al. “One-Step Synthesis of Lead Zirconate Titanate Particles Using a Solid-State Reaction Method.” Heliyon, vol. 8, no. 3, Mar. 2022, p. e09125, https://doi.org/10.1016/j.heliyon.2022.e09125.

Gonçalves, R., et al. “Electrode Fabrication Process and Its Influence in Lithium-Ion Battery Performance: State of the Art and Future Trends.” Electrochemistry Communications, vol. 135, Feb. 2022, p. 107210, https://doi.org/10.1016/j.elecom.2022.107210.

US EPA. “Americium in Ionization Smoke Detectors.” US EPA, 27 Aug. 2019, www.epa.gov/radtown/americium-ionization-smoke-detectors.

Nichols, Jeff. “Injection Molded Plastics at FireBoard Labs - FireBoard Labs.” FireBoard Labs, 4 Jan. 2024, www.fireboard.com/blog/injection-molded-plastics-at-fireboard-labs/. Accessed 12 Mar. 2026.

Baheti, Payal. “How Is Plastic Made? A Simple Step-By-Step Explanation.” British Plastics Federation, www.bpf.co.uk/plastipedia/how-is-plastic-made.aspx.

“Radionuclide Basics: Plutonium | US EPA.” US EPA, 15 Apr. 2015, www.epa.gov/radiation/radionuclide-basics-plutonium#plutoniumsources.

United States Environmental Protection Agency. “Radionuclide Basics: Americium-241 | US EPA.” US EPA, 14 Apr. 2015, www.epa.gov/radiation/radionuclide-basics-americium-241.

World Nuclear Association. “Uranium Mining Overview.” World-Nuclear.org, 16 May 2024, world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/uranium-mining-overview.

Yujie Technology Ltd. “What Is PZT Material? D33, K, Qm, and Selection Guide | Yujie Technology Ltd.” Yujie Technology, 2026, yujiepiezo.com/blog/what-is-pzt/

Jacob Noveman

Professor Cogdell

DES 40

10 March, 2026

The Embodied Energy of A Fire Alarm

The embodied energy that is used during the lifecycle of a fire alarm comes from the energy it takes to obtain the raw materials that make up the fire alarm, and its various components- like circuit boards, and ionization chambers- the energy it takes to manufacture, and assemble the fire alarm, the energy it takes to transport and distribute the fire alarms across various regions, the energy the fire alarm itself takes during its use, and finally, how much energy it takes to recycle or dispose of it. This paper will  focus on the use, reuse, and maintenance stage of a fire alarms’ lifecycle because this is the stage where fire alarms save more potential energy than they use in their lifecycle, and why they’re energy efficient, and eco-friendly.

The embodied energy of a fire alarm starts with  the raw materials acquisition and manufacturing process. This process takes more energy than any other part of the fire alarms’ lifecycle, as extracting the raw materials from the earth takes advanced, energy depleting tools like trucks, drills, and people. The National Renewable Energy Laboratory states that the manufacturing of electronics controllers and various wiring within the fire alarm contributes a heavy initial energy footprint into the total embodied energy of a fire alarm. There are then two cases in which the manufacturing, and extraction process can take even more energy. Some fire alarms, such as those manufactured by Flir, Motobix, and Seek Thermal, are designed with special thermal cameras, and processors that take more energy to produce than a home system. As stated by James John, these monitors are fitted with CO2 and CO sensors to work better in complex environments (Humidity, Extreme cold, etc); however, these sensors on their own take a copious amount of energy to manufacture, and fit into these fire alarms. Additionally, specialized sensors must be used in kitchen fire alarms to avoid triggering them from the steam, or smoke from the stove. According to Siemens, Fire Protection in Kitchens, these sensors cost more to make, and require more energy to make, and attach. Once a fire alarm is built, with all its various materials extracted, the largest energy hurdle comes to a close, and transportation is the next step in the process.

Transportation, while not as energy dense as materials acquisition, and manufacturing, is still a huge energy hurdle with all the gas, oil, and electricity that is used to transport them, via ship, plane, or truck, around the world. As Menzies writes, the transportation of a fire alarm doesn’t even just include the transportation of the fire alarm itself, but the transportation of all the materials needed to build, and install the fire alarm. More-so, buildings often have to be altered in some way for a fire alarm to work, or have the capability to be installed. As Jayasingh, ResearchGate, states, some fire alarms need connectivity to repeaters, routers, or specialized sensors. All of this must be transported, and implemented when considering the embodied energy of a fire alarm. Then there is a final, but small extra energy cost that must be considered, that being the actual installation process of the fire alarm itself, as stated by Andrzejewski. Not to mention the energy cost of the people, and the food they might eat during breaks. Only now, after countless joules of energy have been used to just simply get the fire alarm set up, can it begin its shelf-life.

A fire alarm is designed to run for many years without fail, and only occasional battery changes. The use stage is its most consistent, and calm stage of its lifecycle- unless a fire happens, but that’s what they’re there for. While individually they take a negligible amount of energy to run, in practice, they can be more than surprising with how much energy they consume. As written by the Lawrence Berkeley National Laboratory, 2021, fire alarms are considered ‘Safety, Security, and Health Devices,’ meaning that they must run constantly, day and night, to safely, and correctly serve their function. So, while they don’t cost much energy to run, they must run always which builds up a hefty amount of energy used over time. It should also be noted that a fire alarm can spike in energy usage when there is a fire, and depending on how often, it can lead to a large drainage in power. When a fire alarm triggers, it must be loud enough so that everyone is aware that there is a danger, and must evacuate the building. This means that the amount of energy it takes to blare at that volume for a prolonged period of time can cause a serious spike in energy. It was mentioned earlier that some fire alarms require extra set up to be useful; well this can be seen with lot-based smart systems, which must also be hooked up to the network to increase their effectiveness. As stated by Jayasingh, these systems require continuous power from the internet to keep running, which further contributes to the energy they use while operational. Before discussing the potential energy saved from using a fire alarm, the waste and disposal stage, and how much energy it takes, must be acknowledged.

The recycle, disposal, and waste part of a fire alarm has its own chunk of energy used to contribute to the total embodied energy of the lifecycle of a fire alarm. Disposing of a fire alarm can harshly affect the environment; as said by the National Renewable Energy Laboratory, the data on electrical technologies contributes to a rapid increase in greenhouse gas emissions, as the incineration of various radioactive components can lead to further unwanted air pollution. This means that more effort, and more energy, will have to go towards developing safer methods of disposal for these components, and more energy spent on keeping the environment clean, and safe for everybody. When it comes to actually disposing of fire alarm parts, energy is spent in another way. According to MDPI, Sustainable Process to Recover Metals from Waste PCBs Using Physical Pre-Treatment and Hydrometallurgical Techniques, using furnaces to incinerate these parts must be kept at extremely high temperatures, constantly. In turn, this uses a lot of energy. Recycling does, however, lower the energy cost of the waste stage. When recycling, a product often can skip the first two stages of the lifecycle, and skip straight to the use stage after a little bit of polishing. The LCA suggests that if a system is reused, or its parts are salvaged for maintenance, the total embodied energy per year of service decreases. Not only does the recycling stage save energy, but it leads into the use stage, which although costly in itself, saves more potential energy than energy used during the lifecycle of a fire alarm.

The potential energy saved during the use stage of a fire alarms’ lifecycle is worth the energy it takes to run its course through the lifecycle. Without fire alarms, the damage done to people, property, and the environment from fires would skyrocket, and cost much more energy to fix than to just have the fire alarm. According to, Security in Building Automation Systems, Friedrich Praus, the ‘Fire-LCA’ model demonstrates that the energy consumed by a fire alarm is balanced out by the energy saved when a small fire is prevented from destroying an entire building, and the things inside. This is not to mention the lives that it will save, which will help contribute more energy to future developments, and improvements to the world. Furthermore, it was mentioned earlier that fire alarms waste more energy when set off due to false alarms, but that rarely happens, saving further energy. The maintenance and transmission of faulty signals of fire alarms to emergency centers, prevents them from responding to fake alarms, and helps them reliably find the real emergencies as quickly, and energy-efficiently as possible. According to the Computer Security Resource Center, control units have a brain system that efficiently switches power between sensors and sirens to ensure the system only uses maximum energy when a real threat is detected. 

With this in mind, although a fire alarm can use a copious amount of energy across its lifecycle, it is an energy saver in disguise. Despite the tedious materials acquisition, and headache or assembly, and transportation, to the final use, reuse, and disposal stages, the fire alarm saves far more energy potentially to be used by helping to prevent fire outbreaks, saving lives,and property, and contributing to a safer, more energy efficient world for all.

Work Cited

Andrzejewski, E. (2022). Obsolescence of Labor in Automated Housing Assembly. ResearchGate. https://www.researchgate.net/publication/394348264_Obsolescence_of_Labor_in_Automated_Housing_Assembly

ATL, P. (2024, February 15). Smoke and carbon monoxide detectors: When to replace and Recycle. Eco Actions. https://ecoactions.homedepot.com/blog/smoke-detector-recycle-replace/#:~:text=Smoke%20Detectors:&text=Hazardous%20Waste%20Collection%20%E2%80%93%20Smoke%20detectors,smoke%20detectors%20for%20safe%20disposal.

Granzer , W., Praus, F., & Kastner, W. (2010). (PDF) security in Building Automation Systems. Security in Building Automation Systems. https://www.researchgate.net/publication/224080025_Security_in_Building_Automation_Systems

John, J. (2020). (PDF) thermal imaging in fire detection: Advancements, applications, and future directions. ResearchGate. https://www.researchgate.net/publication/388198187_Thermal_Imaging_in_Fire_Detection_Advancements_Applications_and_Future_Directions

Kumari, S., Panda, R., Prasad, R., Alorro, R. D., & Jha, M. K. (2024, January 3). Sustainable process to recover metals from waste PCBS using physical pre-treatment and hydrometallurgical techniques. MDPI. https://www.mdpi.com/2071-1050/16/1/418

Menzies, G., Banfill, P., & Turan, S. (2007). (PDF) life-cycle assessment and embodied energy: A Review. Life-cycle assessment and embodied energy: A review. https://www.researchgate.net/publication/250073217_Life-cycle_assessment_and_embodied_energy_A_review

Rainer, L., Meier, A., & Hosbach, R. (2021). Energy use of residential safety, security, and Health Devices. Energy Use of Residential Safety, Security, and Health Devices. https://eta-publications.lbl.gov/sites/default/files/energy_use_of_residential_safety.pdf

Shanmugam, L., Rajendiran, H., Dhasarathan, J., & Vimal, V. R. (2024). (PDF) AI-powered energy consumption optimization for smart homes using IOT. IoT-Driven Energy Consumption Optimization in Smart Homes. https://www.researchgate.net/publication/382191360_AI-Powered_Energy_Consumption_Optimization_for_Smart_Homes_Using_IoT

Stouffer, K., Pease, M., Tang, C., Zimmerman, T., Pillitteri, V., Lightman, S., Hahn, A., Saravia, S., Sherule, A., & Thompson, M. (2023, September 28). Guide to Operational Technology (OT) security. CSRC. https://csrc.nist.gov/pubs/sp/800/82/r3/final

Unrestricted fire protection in kitchens. (n.d.). https://sid.siemens.com/api/khub/documents/~xpD61jFI5cvnj4SG77c3w/content

USLCI Quarterly release: Fall 2025 update. USLCI Quarterly Release: Fall 2025 Update | Life Cycle Assessment Commons. (n.d.). https://www.lcacommons.gov/uslci-quarterly-release-fall-2025-update