You know the feeling, you’ve come home from work or school and you just wanna sit down. You slip off your shoes at the front door, drop your bag off on the couch, and stroll over to your desk. There’s a new Youtube video that dropped today from your favourite creator, and you’re excited to watch it. You roll your chair over to the desk, and plop down on the seat. In an instant, you’re thrown across the room. When you finally come to, all you can remember is a loud bang rocketing through your bedroom. You drag your hands across your body to see if you’re okay, when you feel a hot stickiness. You close your eyes, hoping it won’t be what you think it is, but when you bring your hands up in front of you to look, their crimson sheen betrays your injury. Next thing you know, you’re in the emergency room, and surgeons are busy pulling chips, shards, and metal scrap from your abdomen. How could sitting in an office chair go so very very wrong? What makes an office chair go boom? 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Oh, and if you like stories, Crossout even has an adventure mode that you can play on your own to explore the open world, or with friends cooperatively. I particularly like Crossout’s realistic vehicle damage system, so even when someone shoots my tires out, I’m finally one of the cool kids doing donuts. Building your own vehicle is super cool too, with the possibilities to get your ride decked out. Play Crossout for free by clicking our link in the description, and you’ll get a bonus with special parts and paint today! In 2013, university student Mr Liu returned to his apartment he shared with his older sister. After a long day at school, he laid back on his bed to rest while his sister, Ms Liu, who had just gotten out of the shower, sat down at her desk to twiddle around on the internet while blow-drying her hair. Then, with no warning, a sharp bang ripped through the room, and a powerful surge of air followed, throwing the room into disarray. In the aftermath, Mr Liu, still reeling from the sudden pressure change, looked around their ransacked room to see his sister laying still on the floor, her body thrown like a dead thing against the side of their bed. She was still conscious, but just barely, and passed out moments later. With his sister’s blood pooling on the floor around him, Mr Liu called the paramedics, and shortly after, she was hoisted into an ambulance, speeding off to the emergency room. Medical teams got to work on her double-time, and told her family that she’d been injured by an explosion. Her anus had been split open, punctured by fragments of metal, and her genitals had likewise been perforated by shrapnel and debris. Ms Liu was wheeled into surgery not long after getting to the hospital, where surgeons and nurses worked to remove the detritus that had been rocketed into her nether regions. After a gruelling 5 hours, doctors finally stitched up her wounds, but her journey wasn’t done yet. It would take yet another 6 months for her injuries to fully heal. Looking back at the scene in the siblings’ tiny apartment, it was clear where the explosion had originated. The small blue rotating, gas spring operated stool was to blame. The force of the explosion split the foam seat into 4 discrete pieces, and the wooden mount showed a nasty hole where a metal rod had rocketed up through it into Ms Liu. Inside the room, the sibling’s computer had been bombed out by the shockwave, and parts of the plastic casing had melted. Lucky for his sister, the steel rod in the centre of the stool didn’t pierce into her body. If it had, her injuries would have been much, much worse. After interviewing neighbours, journalists found that the sound of the blast could be heard from as far away as 200 metres. Some thought that it was so loud it had to be a gas pipe explosion and called the fire department. But how could a simple stool explode like that? And should I be worried about my rotund tushy in my office chair? The first step to figuring out the truth behind this phenomenon is to learn how office chairs work generally. Basically, chairs are medium sized objects that support our weight that we can use to— So my producers tell me that I don’t need to explain to you how chairs work, but office chairs do have one little mechanism that, quite literally, raises the bar. It’s called a gas spring, and it’s technology that lets these chairs adjust their height. It’s similar to a bike pump, in that it has a metal cylinder with an airtight piston mounted on a rod inside. In a pump, the piston is attached to a handle that you pump up and down. The piston moves inside the cylinder, sucking in air before compressing it through a valve and into whatever you’re inflating. Your tires, your sports balls, and whatnot. In a gas spring, the piston is attached to the bottom of your seat, and the entire cylinder is pressurised with nitrogen gas and oil. The nitrogen is pressurised so it exerts upward force on the piston, which holds your seat at the topmost position. The nitrogen provides the force, and the oil lubricates ensuring the chair works smoothly. Also, since gas springs are holding pressurized gas, they have to be made of metal that can handle the force. Gas springs occasionally have holes in the piston that allows gas to move from one side of the piston to the other. This might make you think that the piston isn’t actually compressing the gas, but remember, the cylinder that contains the piston is gas tight, so when the piston is depressed, the rod itself takes up space that compresses the air. There are multiple reasons for the holes in the piston. One is so oil or other lubricant can move from one side of the piston to the other. If there were no paths from each side of the airtight seal, then the piston would dry out eventually. With a gas spring, pressure can equalize on each side of the piston because of the holes, and the upward force is generated by the higher surface area on the inside. For all my math nerds out there, the equation for this is: Force equals pressure multiplied by area. Since the inside of the piston has a higher surface area than the outside, which has some space taken up by the rod that attaches to your seat, a higher force is exerted on the inside pushing your seat up. Another reason is that these holes improve the smoothness of the spring’s action. Without the equalising pressure, the piston would shoot upward erratically, as opposed to the smooth rise we’re used to. This is similar to why we don’t use regular metal springs in office chairs. Metal springs can hold a lot of energy, but they release that energy all at once, which could, oh I don’t know, explode maybe. So conceptually, the gas springs in our office chairs are meant to contain pressurised gases which, if released in an uncontrolled manner, would violently explode, but our chairs are built specifically to contain that pressure and control it. So what’s going wrong when office chairs explode? To find out why this happens, it helps to look at other examples to see if there are any similarities. For that we can turn to these cases. January 14th 2009, a 14 year old teenager called only Xiao Gang to protect his identity, was injured by an exploding office chair while home alone. The boy went to his computer to go on the internet like so many young folks, when the chair below him erupted, driving a steel rod into his abdomen. As his blood pooled on the floor around him, he dragged himself to a phone and called his father who contacted medical authorities. When they finally arrived, Xiao Gang was looking very pale from blood loss, but was still conscious enough to speak. Xiao Gang was taken to the Jiaozhou City Centre Hospital where doctors worked to save the boy’s life. He was bleeding internally, haemorrhaging blood, after the rod that had been embedded inside him had damaged blood vessels around his wounds. Tragically, doctors weren’t able to get a handle on the boy’s blood loss, and within an hour of arriving at the hospital, he had passed away. His father said after that he “never thought that a child just sitting on a chair could have any type of accident”, and that “This type of pressurised cartridge going out of control is definitely a quality issue” Another case from November 2007 out of Yantai City describes how a 68 year old man was taken to the hospital after his rotating chair exploded. He was taken to the hospital in shock and similarly suffering from blood loss like Xiao Gang. He had serious rectal injuries including a rupture in his small intestine. Some of the damaged tissue had tears as wide as 5 centimetres. By the time his surgery was over, medical teams pulled more than 20 fragments of metal from his body, as well as chunks of wood and foam. Not only that, but the steel rod from the gas spring had been driven into him as well, and had to be removed. Horrifyingly, a doctor present said that the rod had been shot into the man from the blunt side, and the explosion had to be powerful enough to sever it from its mechanism entirely. Basically, the explosion had to be giant. The phenomenon of office chair explosions seems to be certainly real, but why do all these stories seem to come from China? Also, noticeably, within China, the distribution of incidents seem to correlate by distribution of population. Which is only interesting insofar as it’s totally normal. This is likely a pure luck situation, not something localised, like lower standards in a particular factory, or some regional standards having lower oversight. With this in mind, we can turn to news reports from Ms Liu’s case that note price discrepancies between office chair costs depending on modes of production. Basically, how raw materials—metals, etc are crafted into modules—springs, rods, etc, which are then constructed into components—gas springs, which are then assembled into office chairs. In the report on Ms Liu and her brother, we learn that when office chair components are assembled in Guangdong then imported to Xiamen for packaging and assembly, the chairs are trademarked with company contract details which guarantee standard safety requirements, and priced accordingly around 40-50 US dollars. However when modules like springs and metal rods are imported to Xiamen, instead of purchased from a supplier, and then constructed, the same safety standards can be avoided, and the price lowered, to something in the ballpark of only 20 dollars US. Basically, a chair company can buy already constructed gas springs from a factory for a higher price, or they can buy the parts to make the gas springs, build it themselves, and save a buck. The problem is, they’re not held to the same standards as the factory that sells the springs wholesale. So it could be good, could be bad, it’s an odds game. It’s a little bit like getting news from Tiktok. The question remains though, what is behind this string of office chair explosions? “Seeking Truth” a Mythbusters style television show from China tested this exact scenario for us. The showrunners took three different chairs and dropped heavy sandbags on them to see how they could withstand the impact. The first chair was from a reliable and well known retailer, with info about the manufacturer and certification guaranteeing safety standards. The second was purchased second hand, and had some visible damage on the column that has the gas spring. The third was bought from what the hosts call the “third market” in China. Basically the black market, out of the eye of the government. In the test, the well-made chair fared well. The seat, which isn’t attached but sitting on top of the base, fell off, and all of the components showed very little damage, if any. The secondhand chair did less well than the first. When the sandbags landed on the seat, it exploded into a flurry of metal and plastic. You can see that there is a hole burst through the middle of the seat, and the metal piece that mounts the height controls has been violently bent. The black market chair handled the weight the worst. When the sandbag hit the seat, not only did the chair explode, but it erupted into flames. Setting the whole chair alight. It’s nice to see that when these chairs are built properly, they can withstand a certain amount of force, but we still don’t know why. Seeking Truth spoke to Guo Liang, a researcher with the Chinese Academy of Science, Mechanics Research Institute, who told the hosts that there are two main reasons why these chairs can explode. The first reason we witnessed in the experiment with the secondhand chair. He tells us that if the gas spring has a crack or some other damage, it can no longer contain the pressures required to operate, and when weight is dropped on the seat, that pressure escapes violently. AKA an explosion. It’s like sitting on a blown up balloon. There’s a pressure inside, as as you add weight to it, those pressures increase until the latex of the balloon can no longer hold it back. If you jump on top of a balloon, it’ll pop even harder. The second reason explains the fiery explosion of the third chair. Liang tells Seeking Truth that many under-the-table products use cheaper gases like regular air instead of non-flammable gases like nitrogen. Now, you might think “Wait, air isn’t flammable!” which you’d be mostly right. However, on a chemical level, oxygen is one of the core ingredients of fire. Combustion is defined as the combination of oxygen with another substance that generates heat and light. On a similar note, the higher the pressure the faster and hotter a fire will burn. However, if the manufacturer puts an even more flammable gas into their spring than regular air, you can see much, much, larger reactions. On top of that, when pressures rise, so too does temperature. Seeking Truth even tested this by raising and lowering a chair’s seat for 20 minutes, and then taking the temperature of the gas spring. They measured a rise to 45 degrees celsius, but thankfully there were no sign of any explosions or fires of any kind. Probably because the chair they used was the most expensive they could find and likely used the proper nitrogen in the spring. In short, all office chairs use gas springs which contain pressurized gas, which if the casing is damaged, can violently depressurize triggering an explosion. Not just that, but if the manufacturer uses oxygen in the spring itself, then that compressed gas can also combust, adding fire to an otherwise already terrible situation. Office chairs aren’t the only appliances around our homes that use pressure for our needs. At this very moment, you may be relying on hot water under pressure in a water heater for showering and washing your dishes and clothes. You may have used a pressure cooker, or an instant pot, that uses steam to build pressure inside of an airtight “pot”. You might have also seen automatic door closers in schools and public buildings that use pressure to shut themselves. But much like office chairs, when the mechanics are damaged, they can fail to catastrophic effect. What we can take away from this is that power, in almost all forms, is dangerous if uncontained, but when harnessed properly, it can make our lives orders of magnitude easier. Office chairs use the power of pressure to make it easier for us to get comfortable, but when the mechanism that we use to contain that power is damaged, or made incorrectly, then disaster can follow. So yes, there have been incidents of office chair explosions, but most of us aren’t even going to be able to buy a chair of such low quality that this is an issue. Like Seeking Truth told us, the chair that failed most horrifically had no safety standards whatsoever, and no manufacturer label to hold them accountable. As long as we buy office chairs from reliable suppliers and other major retailers, then we’ll be perfectly fine. If you want to check any chairs that you have around you, you can find a label, usually under the seat, that identifies that it is up to the regulatory standards in your country. If the label isn’t there, and you weren’t the one to remove it, it could be a sign your chair isn’t up to code. If you’ve been using a chair for more than 3 years, double check the mechanism to make sure there isn’t wear and tear, and consider getting a new one if you have the money. It should also be said that office chairs have weight limits, and exceeding that limit can lead to disastrous ends. But even if you don’t exceed the weight limit, as a chair ages, the weight that your chair can handle will be reduced. In the end, if you just check your office chair for damage and replace them when you can, then you can make sure you’ll always chair well. Get it? Like “fare well”, it’s— oh there’s the end card there it is. It’s over. Remember, click our link in the description and play Crossout for free on PC, XBOX Series X and S, and PS5 and get your exclusive bonuses— special parts and paint now! See you out in battle!