Cylindrical aquarium housing 1,500 exotic fish bursts in Berlin
theguardian.comFrom an engineering perspective these sorts of acrylic tanks are a nightmare to ensure they are safe. The seams are impossible to inspect rigorously so the only real way of checking that they are safe is to load them with an excess pressure ( https://en.wikipedia.org/wiki/Hydrostatic_test ). This can't be done with a tank of this size so the engineers can only real fall back on giving the tank excessive safety margins. But those safety margins cost hundreds of thousands of dollars for a tank this big so maybe they were reduced.
All it takes is one incorrect application of a seam bond and a small crack will form. The crack may take decades to propagate with no way of detecting it. When the seam opens up a bit the crack will then propagate the entire length of the seam extremely rapidly and the whole tank will fail. Ideally failures would be slow and predictable but this is impossible with acrylic.
These sorts of failures have occurred before https://www.plasticstoday.com/materials/when-acrylic-aquariu... and will keep occurring as long as this type of construction is used.
I just saw a documentary (in German) from 2003 about its construction. There is an interview with a guy from the American (Colorado) company which built the tank who boasted that only two companies in the world could build it and the other one declined because they deemed it impossible. Other interesting facts were:
- 15 segments of acrylic glass
- 12 segments for the outer cylinder, 3 for the inner
- all segments worth 4 million EUR
- 200 wall thickness
- shipped in a steel construction
They did not say it, but from the video it looks like the segments were assembled in at the destination but not in their final location.
EDIT: I misunderstood, looks like the outer cylinder was assembled in-place, the inner one on-site and then lifted inside.
For completeness, here is the video, but it is in German:
Great engineering feat but it was a dumb idea to begin with. Just like sending people to Mars. Luckily nobody died, excluding the fish of course.
This is tangent from the topic at hand but I'm curious to pick your brain. Why is it a dumb idea to send people to Mars?
For the same reason it was a dumb idea to put a dog in orbit without the means to return it back to Earth alive.
The thing was just recently reopened after revision, here is an interview after the overhaul: https://www.domaquaree.de/de/Modernisierung-AquaDom.html
Interesting bit:
> It got a little tricky when taping off the glass envelope with foil to prevent possible cracks. Acrylic glass is a sensitive material that absorbs water over time. If it then dries out too quickly, cracks can appear even in the glass walls, which are up to 20 centimeters thick.
Is there no way to detect cracks or is it just prohibitively expensive to do so?
I know that metal fatigue is a known thing that airlines check for and when they went to carbon fiber they had to develop tools to detect fatigue/cracks.
From my limited knowledge[0], it does not seem like this would be an easy structure to scan for inspection. Acrylic can even used for the wedges that interface between the phased array (or single element) probe [1] because it's very good at not interfering with ultrasounds. Water is also a very good "coupling" material, which makes it even harder to get a useful scan since there would be no "backwall" reflecting back the ultrasounds on the other side of the acrylic.
There are other ways to scan for defects, but I'm mostly familiar with ultrasound phased arrays. Other NDT methods are also hard to use in the field after manufacturing.
[0] I work in NDT (non destructive testing), but I'm not a physics engineer and (work further up the stack from the actual probes/scanners). So this is an approximation, and I might be wrong.
[1] This random link is pretty useful to get an idea I think, but I'll also ask around our inhouse scientists if I get the occasion today!
https://www.olympus-ims.com/en/ndt-tutorials/transducers/pha...
So it sounds like you'd need something on both sides of the "glass" kind of like this aquarium magnet but much larger/complicated: https://www.amazon.com/JRing-Aquarium-Cleaner-Aquariums-Clea... and slowly move it around the whole tank, repeatedly scanning as it goes.
So I'm going to put it in the "theoretically possible but nobody will do it" category for now. ;)
It's a much harder problem than that. Even if you did not find the crack just before taking the structure into use a crack could develop at any point in time after that and you're definitely not going to be emptying this tank on a regular basis for inspection.
So you either detect it before commissioning or it will eventually fail if there is a flaw.
They had divers regularly going inside to clean it anyways. Doesn't seem like such an unlikely thing.
Acrylic and water have virtually the same index of refraction, so if the crack forms on the wet side of the wall and wicks in water you will not detect it visually.
It forms the basis of some magic tricks involving walking on or supporting things in water. (I say some, the rest are totally magic and you should enjoy them.)
I just realized that water can be safely colored
Also, they focus on aesthetics.
They could have steel bands providing reinforcement which would be just slightly obtrusive at some angles, but boy, now it would have bands and well, it's not an uninterrupted glass [acrylic] cylinder.
The article specifically says that this particular aquarium was made of glass?
The article does, but "the AquaDom was a 25-metre-tall (82 ft) cylindrical acrylic glass aquarium"[0] Turns out that's just poor reporting, they could have been more specific. It was the largest (by volume) acrylic cylindrical aquarium in the world.
Thank you barbegal. Given the height and water volume in this instance, do you consider the people involved took too huge a risk? I do believe acrylic is used in aquaparks and zoo aquatic pools. I skimmed instances of acrylic/water fails. Dare I ask, is acrylic construction a significantly cheaper option to solid alternatives?
There are no real alternatives. Glass has mostly the same bonding issues but is more expensive and heavier. Putting acrylic or glass panels in a steel frame dramatically reduces the probability of failure but you lose the wow factor of having a single sheet of transparent material.
I don't think any installation of this size can be truly safe. It has to be constructed in-situ being too large to transport so you would have to come up with some way of pressure testing the tank in-situ.
Would it be possible to construct a seamless acrylic tube, maybe on-site?
Not of this size. Certainly single pieces are used in other applications where safety is even more critical such as submersibles. But manufacturing a tube this big would be impossible.
Impossible to manufacture? Or financially impossible to build a factory for the purpose and larger infrastructure to accommodate transportation?
I'm curious if there is something about acrylics which makes it impossible to make very large single pieces.
I guess you could transport it at immense cost. But you'd also need a machine capable of moulding or extruding it this big. Current maximum for plastic pipes is about 3.5m diameter https://www.agru.at/en/applications/agruline/grand-opening-r... so you'd need something which is capable of more than 3 times the diameter.
Could one pour liquid acrylic into a mold (like with a concrete foundation), rather than extruding it?
You're making me think of this industrial scale 3D printer: https://www.youtube.com/watch?v=vL2KoMNzGTo
That's cool but it's all seams with 3d printing, so it seems like that would make the problem worse.
By the way, here's a big cool 3D printer that prints opaque acrylic: https://m.youtube.com/watch?v=b3CY3P28qyQ
What's the best material for a tank like this, if not acrylic? Normal glass? Not educated on this subject.
Ideally it would be extruded diamond, but that technology will not be available until early in the 26th century. Second would be clear aluminum, but again that will not be available for another 150 years.
Just one question: Why did you give my homie Stephen Hawking the cold shoulder when he hosted a party[0] for time travelers in 2009?
[0] https://www.atlasobscura.com/articles/stephen-hawking-time-t...
The entire problem is that acrylic is not plastic enough, so it fails catastrophically. Well, diamond has all the nice features for structure building, but it's even britter than acrylic. So your sci-fi diamond tank would fail in an even more sensational way.
We have clear aluminium already in the form of sapphire glass (Al₂O₃). Presumably you're referring to a means of manufacturing it at a scale suitable for, say, an aquarium?
It's a Star Trek joke: https://www.youtube.com/watch?v=Wv5FGCeIP8I
Polycarbonate is stronger and more shatter-resistant (it's used for fighter jet canopies, among other things) but also substantially more expensive.
Acrylic is the best material for this application we currently have. If we had a better material, we would use it.
Transparent aluminum
maybe we could focus in shape also, not only material.
They should've made this tank with transparent aluminum.
If you're curious about the design considerations and construction techniques for large aquaria, the standard reference is Stachiw's Handbook of Acrylics for Submersibles, Hyperbaric Chambers, and Aquaria: https://www.bestpub.com/books/product/cid-151.html
Plastics are weird, and examining the wreckage will give a lot of information about the failure mode.
A column of water that tall is nothing to mess around with. Even the smallest imperfection in the base materials can become a problem.
170.65 kPa, or 24.75 psi. I imagine even Flex Tape can't hold that!
Doesn't seem crazy, my tires hold 38 psi.
PSI is a measurement that can be hard to translate between various items like tires and tanks and foundations: https://www.engineeringtoolbox.com/building-foundations-load...
Massive tractor tires can be 50+ psi and when they pop it is devastating.
That can kill you. In fact even a personal car tire that goes can wound or kill you if you happen to be holding it.
Go look up split rims exploding on youtube. It's violent and probably a good thing those fell out of fashion.
Side note: tractor tire inner tubes make great trampolines. My aunt and uncle run a small farm (one farm over from the farmhouse where my mom was born) and gave us a tractor tire inner tube when I was young, and we jumped on it enough to require several patches throughout the years.
In contrast, my bicycle tires at are 130psi, and while loud, the explosion is minor. I think the amount of air/water/matter escaping is part of the equation, but someone more physics-inclined could probably ascertain to a better degree how this affects the outcome.
Even my compact saloon cars tires take 45psi
Road bike tires go up to 150 or so... but that doesn't really matter, what matters is that the surface here is massive and you need to withstand all of the force evenly or it will go. Even one crack would do it, it's not going to just seep out water but explode along the fracture, much like a popped balloon isn't going to gracefully deflate.
Exactly. I shield my anatomy when inflating my tires.
Watch this guy be very lucky:
https://www.youtube.com/watch?v=B3U3ClFRjrQ
Compared to the side of the truck...
And they are steel reinforced to be able to do that.
There are now many reports about material fatigue as the primary cause, but I am not so sure. Another article [0] mentioned that the building is currently analyzed by engineers because the firemen found cracks in floors and walls - they are, however, not sure if these cracks were caused by the water, or if they were already there before.
In the latter case, something could be wrong with the building's foundations. I am no expert, but if such a massive aquarium is only slightly tilted to one side, I would expect the forces acting on the glass to be ill-distributed. Material fatigue would then only be a secondary cause.
[0] https://www.faz.net/aktuell/gesellschaft/ungluecke/aquarium-...
The hotel was told to lower their temperatures. With cold weather outside the differential between the tank and the lobby is the most likely cause.
That's a good guess, but I'd still like to see the final report if and when it is published and whether or not they manage to find the root cause. Likely the differential made the problem worse to the point that something gave but I suspect that there is a deeper underlying cause that made it sensitive to that difference in temperature to begin with. Either a material flaw, an assembly issue or something else.
Seems to me it must have been a salt water tank if it had clownfish, and they are tropical so it's not just exposing the acrylic to constant warm water, but a more realistic marine environment.
In the lab I've chemically tested acrylics that were bullet-resistant at low-cm window thickness. No bullets were used in my phase of the operation, but I was clipping off chips from the exact coupons which had been physically measured beyond the fracture point.
You can tell there's a difference in ductility and brittleness with temperature. Pretty tough stuff regardless.
In the aquarium these are supposed to be very thick-walled acrylic curved panels bonded together.
If the water was maintained warm enough for the reef fish while the ambient air dropped below freezing I don't like that idea. The entire temperature differential being borne by the thickness of the acrylic could mean there are different plastic properties diverging among the inner and outer surfaces of the "glass" panel. This could give rise to stress being concentrated deep within the panel if the transition is not too smooth.
Conditions like this could be recreated if so.
Might have been OK if they had penguins and cold-water fish this time of year.
I'm basing it off of what this guy is reporting. He seems to have an inside legit view. https://www.zerohedge.com/user/105370
There are some eye witness accounts about corrosion around the base of the tank. One way in which that could have caused this is because corroded metal takes up more space than the original and this could put point stresses on the acrylic. I haven't seen any engineering drawings (I did try to find some but there are only pretty pictures) so I'm not sure how much effect that would have but keeping the base corrosion free would seem to be an absolute requirement regardless of whether or not it would have a disastrous effect like this. So I will have to wait until the investigators have gone all over this, given the amount of money involved there is bound to be a very thorough investigation and after having seen a couple of aircraft accident investigations conclude with entirely different findings than the first 24 hours of speculation I've learned that to be patient usually pays off.
That is fair. Security tapes might tell a lot as well.
Those will definitely be interesting, if they are leaked. Let's hope the cameras have a high frame rate because the first couple of frames will be the most interesting with respect to where the failure started and how it propagated.
In the Panama City there is an overhead swimming pool many meters above the restaurant floor. I've dined there a couple of times and never feel quite comfortable with that much water hanging over me supported by a sheet of acrylic.
After this that feeling is likely not going to be any less :)
Zero Hedge is not a reliable source of information. They also tend to push a lot of Russian fake news/propaganda. And of course Putin would love to have a major news item showing how the West’s gas sanctions have harmed the West.
Yeah, it's a nice balance to the murican propaganda.
Wow, that guy is ... extreme. I'm glad you posted the link, but I'd personally take any conclusions he draws with a grain of salt.
Why would you expect the forces acting on the glass to be ill-distributed if the enclosure were tilted slightly? Water pressure acts hydrostatically. The enclosure appears to have a circular cross section. As long as the tilt is not severe there is no reason to believe anything other than tensile hoop stresses due to equal circumferential loading will develop.
The normal force of the tank wall to the floor will shear across the acrylic if it's not perfectly flat. Pressure outwards is normal to the tank wall relative to the water, but if this force goes diagonally through the floor, that's bad.
If the tank burst due to it shearing off of its base then it is not the glass that has the problem; it’s the connection to the base. This might sound pedantic but the OP said the forces on the GLASS were ill-distributed. The most important part of after the fact disaster analysis from an engineering context is being excruciatingly specific about the performance of structural elements.
If you wanted to be pedantic you would correct the statement because there is no glass.
To be excruciatingly specific.
The article refers to the aquarium as glass throughout it.
The material used is plexiglass, aka acrylic, a type of clear plastic. Actual glass is probably too brittle or expensive.
People use "glass" to mean the clear part of a window, not the actual material, in this context.
Plexiglas®
A trade name.
I'm glad to hear that you'd agree with me then that a correction saying "there is no glass" would be inappropriate because when someone says glass they mean the clear part of the tank.
This may or may not be your intention, but fyi you are coming off as extremely condescending bordering on /r/iamverysmart level tones.
I'm no expert, but I know that a hot tub on slightly uneven ground has a good possibility of bursting and ruining the tub due to how much stress the water will unevenly put against a side. I don't see why the same underlying reasons wouldn't apply here too.
But isn't the overwhelming majority of the glass material connected to the base by the glass itself (namely the glass below it)?
That all depends on whether the underlying surface is still perfectly flat around the perimeter. If it is not then you get local stress variations that can lead to catastrophic failure.
The seams between the panels are likely also not designed to be loaded that way.
Just the asymmetrical load on the structure could do the trick at a relatively small angle because it might cause the structure to get compressed against something bordering it. This is not a trivial engineering project.
I would expect it's not the tilted slightly that would matter but simply settling after installation - a settling foundation can crack concrete and glass so stresses could change if the foundation of the tank was moving.
Considering there was a hotel lobby under the aquarium, it's actually a miracle that only 2 people were hurt. Too bad for the fish though.
Also, there's a sentiment of "how could this happen, it was only upgraded two years ago?!" in all the articles I have read so far - maybe it happened precisely because of that? But let's see what the investigation will reveal...
> it's actually a miracle that only 2 people were hurt
It probably helped that it happened at 6AM ...
as someone who has an aquarium, i'm amazed it didn't happen in the middle of the night. Any time I've had an overflow issue or something, it's always in the middle of the night and my water sensor is blaring
I’m renting a house with three bathrooms. Two of the three toilets, on separate occasions, spontaneously cracked and leaked water. Both happened between 5am and 6am-ish. I was awake for one and heard it, and woke up shortly after the other one happened and found my kitchen flooded. The cracks in the two toilet water tanks were identical. Given the comments about the water temp and lobby temps, I’m guessing that hour and temperature changes could be linked.
I was able to get the owner of the house to see the wisdom of replacing the third toilet water tank.
Yes, it could have been much worse if it had happened at, say, 6PM. Although some hotel lobbies can start to get busy even at that hour (airport hotels, etc).
even earlier, 5:30-5:45 actually reported by guests, 5:43 fire alarm after broken front glass
preliminary cause - material fatigue
I know people got hurt (and fish died) but all I can think is, this is a hotel lobby, there most certainly IS security camera footage of the failure and subsequent deluge and man do I want to know what that looked like.
There might be legal/liability reasons why they’re not releasing the footage immediately.
Reminds me of the Champlain Towers accident - there were surveillance cameras everywhere, as well as a fire alarm control panel (that was critical to the incident as it would’ve been the one triggering an alarm to prompt everyone to evacuate) but no efforts were made to recover either despite the fire alarm panel checking in with the control centre several times (on battery power, over a mobile phone connection) after the collapse, proving that it was still alive and recoverable.
I guess they worked out that it was better to play dumb and let this evidence go away than recover it and potentially get into more trouble. I suspect it’s the same situation with the aquarium.
There likely will not be more than a few stills worth of interest, this happened very quickly judging by how far out the street is contaminated.
Previous thread, with link to article in English:
https://news.ycombinator.com/item?id=34012469
Before: https://www.sueddeutsche.de/image/sz.1.5716681/1280x720
After: https://www.sueddeutsche.de/image/sz.1.5716703/860x1290
It seems like the inner glass (for the elevator shaft) is still intact.
What a pity, it looks amazing.
Link to English article:
https://www.theguardian.com/world/2022/dec/16/huge-cylindric...
> A freestanding cylindrical aquarium housing about 1,500 exotic fish has burst in Berlin, causing a wave of devastation in and around the Sea Life tourist attraction, police have said.
> Glass and other debris were swept out of the DomAquarée complex, which houses a Radisson hotel, a museum, shops and restaurants, as 1m litres of water poured out of the 14-metre-high tank shortly before 6am.
> Operators say the aquarium has the biggest cylindrical tank in the world that contained 1,500 tropical fish of 80 different species before the incident.
> The aquarium, which was last upgraded in 2020, is a big tourist attraction in Berlin. A 10-minute elevator ride through the tank was one of the highlights of the attraction.
> 14-metre-high tank
> 10-minute elevator ride through the tank
That's 1.4 meters per minute, or ~2.3 centimeters per second. The aquarium and the fish in it must have been marvelous to watch, because otherwise even imagining being stuck in an elevator moving at this pace feels terrifyingly boring to think about.
You've never sat on a bench for 10 minutes to look at something neat? They move even slower.
It's a tourist attraction as part of the aquarium, not a tool to get from A to B; the hotel had its own regular elevator.
Yeah it was quite nice. They’d feed the fish too and they’d all scramble for it.
The issue was caused by the forced reduction in heating due to energy sanctions. The decreased warmth of the lobby caused the aquarium, which was sensitive due to its size and construction, to contract and contort to the point of structural failure.
Do you have a source on that?
Too early for an official RCA, but the surrounding facts of the known temperature sensitivity of the aquarium, the energy reduction mandates in Berlin, and the unusual cold point to that as the most likely cause.
This poster on Zerohedge provides more details:
I am directly involved in the legal cleanup of this and can provide a little more detail as to what actually happened (Tyler, reach out to me you have my email if you'd like to verify my identity here).
The city of Berlin required the hotel reduce the ambient temperature of the hotel lobby to save on energy due to sanctions. Its been abnormally cold in Berlin the past few nights dipping down to -11°C last night and -12°C the night before that. The water is heated to a constant temperature above 30°C for many of the fish species that lived in the tank.
As the nights got colder and colder, the lower ambient temperature of the air surrounding the tank likely started causing deformations and hairline cracks in the bottom of the tank where the pressure is the greatest. Last night at -11° caused the ambient temperature to drop too low given the reduced heating in the lobby and is what it looks like caused the "sudden unintentional disassembly"/catastrophic failure of the tank.
Everyone is already lawyering up including the city, the HVAC manufacturer, tank manufacturer, HVAC installer, building engineer, hotel - the litigation is going to be fun to watch and work on.
What isn't covered in the news is damage. The tank in 2003 cost €13 million. Today its orders of magnitude more expensive to replace, some of the fish were quite exotic and are expensive losses in and of themselves. Then you have the damage to the hotel lobby and façade, electrical components of the building in the three-story basement are also effected and large amounts of water went into the parking garage where many vehicles are parked not only from the hotel and offices but from an attached apartment complex to the hotel.
Losses are tens of millions. All because the city made the hotel turn down the heat.
2011 - Nord Stream gas pipeline opens, 2022 - the world's largest acrylic aquarium in Berlin disintegrates due to the sanctions. What a beautiful butterfly effect... I'm afraid we'll see more of similar incidents in the coming months...
> All because the city made the hotel turn down the heat.
That's a little bit early to start aiming at the city, isn't it? The call to reduce energy consumption is, if anything, coming on as a case of too little, too late if anything given the ongoing crisis over here; it is altogether a reasonable thing to do. As is always the case in Germany with such things, there will be maddening array of if/then/otherwise escape hatches that is part of those rules, and, frankly, if the management of the hotel and the people responsible for the aquarium had been in the know that keeping a constant temperature in the lobby was essential to the structural integrity of the aquarium and they still lowered it, they're mad. If they weren't told they can't be held responsible. If the manufacturer did know or should have known, they'll be in (sorry) hot water.
All of this is conjecture at his point so phrases like "all because the city told them to turn down the heat" have to be understood in the conjunctive or, better, be explicitly written in that voice.
Whenever I hear people describe a complex chain of events only to conclude that there was a single root cause, I'm reminded of the old proverb:
>For want of a nail the shoe was lost.
>For want of a shoe the horse was lost.
>For want of a horse the rider was lost.
>For want of a rider the message was lost.
>For want of a message the battle was lost.
>For want of a battle the kingdom was lost.
>And all for the want of a horseshoe nail.
The moral of the proverb is: it is important to ensure that critical systems have redundancy built in.
Someone else posted a link to the source for this quote: https://www.zerohedge.com/user/105370.
The writer pretty clearly has an axe to grind with the city, the sanctions, the war, and a lot more (read some of his other comments). His conclusions might turn out to be true, but I don't think he cares if they are or not.
Also, the guy uses the "Reichsflagge" as his user picture, which is a pretty sure indicator of him either being one, or at least sympathizing with, right-wing nutjobs. These people are very quickly jumping to conclusions that fit into their irrationally-distorted picture of the world. And very bad at accepting even obvious facts that counter their worldview.
According to a german news report [1], it could be due to material fatigue.
[1] https://www.rbb24.de/panorama/beitrag/2022/12/berlin-karl-li...
Yes, that is widely reported now as a very preliminary cause. Also that it has been completely modernized in 2020. Here is a promotional video of the renovation activities: https://vimeo.com/530397162
Fatigue from what? It's a stationary object housed indoors, not a car or plane that goes through several climatical, temperature and environmental changes to cause fatigue.
Unless they were subjecting the tank to draining and filling cycles often, it seems more like a design/build fault that was a ticking time bomb from the start.
The fact an object is stationary doesn't mean forces aren't continuously being applied... Same goes for bridges and every load bearing object.
Bridges are outdoor subject to weather the forces of wind and the weight and harmonics of vehicles and people crossing them constantly.
A fish tank a relatively constant by comparison.
The fish were having a race.
Gravity.
Edited due to incorrect assumption.
I'm no engineer but this would be static fatigue[1], no?
"[S]tatic fatigue occurs during prolonged and constant application of stress" (my emphasis) - much like the glass/acrylic at the bottom of a 14m high, 1M litre water column, say.
Interesting I didn't know that. Thanks for sharing.
Settlement of the building it's housed in, temperature variations (things contract and expand as temperature changes), random impacts and vibrations (e.g., road traffic, heavy construction nearby), and so on. All of these contribute to fatigue.
A tropical aquarium is keep at the same temperature. Unless somebody would disconnect it to save energy or the termostat[s] would fall, shouldn't have experienced a lot of changes in their volume by this.
It’s unlikely a structure this size has a temperature uniform enough consistently over time to avoid thermal fatigue.
Not so much. A big mass of water act as a temperature buffer and air pumps and filters are mixing the water column all the time. It takes several hours to cool.
The event does not seemed truly random to me. If it was, the probability of breaking in the 90% of the time when there was people around would be much higher than breaking in the 10% small time interval without people. Extreme luck is rare. Looking for an external trigger seems appropriate
But the only surface really accessible to people was the escalator, and now we know that it didn't broke. The outer surface is mounted over the escalator door, can't be scratched purposely without taking a lot of troubles. Can't be shoot without leaving evident marks of a crime
If we assume that the thermostat didn't broke and that material fatigue is not an optimum explanation (it was checked and maintained in 2020), then temperature differences seem a good candidate. It broke in winter, in the hour where day/night differences should be maximum. The outer temperatures that night were -10C if I'm not wrong.
The hotel was required to reduce its lobby heating due to energy sanctions.
Maybe the insurance companies could sue the government if this was indeed the case. I would really like to see the bad policy makers go to jail or get hit with huge fines.
Hum, A graph of the aquarium water temperatures by time would be interesting to examine...
The aquarium was likely very constant (otherwise the fish would die, they tend to be extremely sensitive to variations, especially rate of change), but the surrounding air likely was not.
Those fishes can stand an interval of temperature if changed slowly. A main question to check would be if the thermostat was deliberately lowered by the owner in the previous weeks to save energy
Thermal cycling is one option.
Building temperatures were mandated reduced due to energy sanctions. This put stress on an already sensitive structure and caused it to fail.
This is speculation, not established fact.
Of course it is. At this moment everything is speculation.
Buildings move.
This here.
The earth you live on is not solid, more like a squishy orange. When you build a heavy building on it, the building can sink further.
Buildings themselves are subject to the dynamic loads of temperature, wind, their occupants square dancing, and more.
Sometimes unexpected loads are added. A new highway or building built into a rock layer near it can subject the previous building to vibration and other forces and cause damages.
This, and it's in particular true for this very part of Berlin, a city that is well known for literally having been "built on sand", see https://de.wikipedia.org/wiki/Palast_der_Republik#Abriss_zwi... which is about the demolition of the comparatively big building of the Palast der Republik which was just across the street on the other side of the river. That building had to be carefully and slowly dismantled to avoid sudden changes in the hydrogeological (?) equilibrium of the load-bearing layers.
Given that amateur seismic stations located 8 and 14 km away from the location were able to pick up a signal from the event[1] of a 1000 tons of water falling to the ground from a height of ~ 2 to 15m, one should image the building itself should have had some sort of influence to its immediate surroundings.
[1] https://twitter.com/ErdbebenDE/status/1603654695293263873?re...
Sand is - strangely enough - quite stable. Clay, peat and lots of other substrates are a lot less stable than sand and when building on them you need to take all kinds of precautions to ensure your foundation doesn't one day go for a walk.
If it's due to material fatigue it's due to engineering failure. That in turn may or may not be due to the yes-men promotion mechanism.
The tank was around 20 Years old. How is material fatigue an engineering failure at that age?
If the engineers didn't know it would fail in 20 years from material fatigue, that's something that should be learned.
They may be blameless by any reasonable standard, but knowing how/when something will reach end of life is an important part of design. We learned a similar lesson with airplanes.
20 years is a very long time for a structure under such extreme stress. You can bet that this accident will influence all such designs and cause a structural review of every other large tank made of acrylic in the world, as well as various under water tunnels in large aquaria.
> yes-men promotion mechanism
huh?
People who say yes without questioning their superiors or clients tend to get promoted.
This is what I assume they mean.
I stayed at the Radisson in 2019 for ICFP and was astounded at the poor quality of the building, which was undergoing renovations at the time. I distinctly remember noticing visible corrosion around the foundation of the tank structure.
It's just weird learning about interesting engineering accomplishments by news that they're gone forever...
Agreed - it would be a interesting blog to report on these kind of things before they burst.
I know of the aquariums with tubes under/through the water, but this seems to be something different.
I had no idea this existed - all those visits to Berlin, wasted.
Looks like it was a remarkable elevator ride.
I can confirm it was a great place to visit. I went there 2018 even as a Berlin native. The highlight of the tour was taking the elevator into that water dome. Impressive stuff.
Too sad it’s destroyed - hope insurance will cover all the damage. I wouldn’t want to switch places with the owner currently…
Thanks for the video link. You can see a seam in the tank as the lift rises.
Weird. Earlier today I awoke from a nap after strange dreams and attempted to produce images in midjourney of a giant aquarium breaking. I must psychic or something.
Shit happens with my wife All. The. Time.
We're rational enough to mostly chalk it up to coincidence or selection bias, but not calculating enough to take advantage of gullible people
(Edited to mention selection bias)
You can chalk it up to selection bias, you never remember the predictions that were just garbage.
It's Midjourney. It has me wandering the uncanny valley for hours every day, there is so much undiscovered country. My sleep is disrupted. I'm in an altered state and I'm more tuned to recognizing coincidences and generally making associations between images that may or may not be floating around in the latent space.
For pure curiosity, could you give us some examples of what happen with your wife? Thx
Case in point - yesterday morning she told me about a vivid dream of a major apartment fire she had. Look what just happened in Lyon [0].
You could dream about a fire for any reason, and fires are unfortunately common enough to at least make local news so unconsciously scanning a headline during the day may plant a "dream worm".
But this happens quite often, even for personal things, like details of the birth of our first kid a couple of weeks before the due date, down to the amount and color of hair, the precise time for a natural birth, and the mino complications right after.
It always gives me split second pause because I want to believe ("quantum entanglement" is weird or witchery is real - she's East European after all). But there's almost always a good explanation for the percieved prescience.
Interesting. I'm not sure chalking up an observation is the rational approach. I'd be looking into the Pauli-Jung conjecture before doing so.
Please dream of me winning the lottery and or becoming 10x dev.
You do realise that becoming a 10x dev will mean you're getting underpaid? It's better to become a 0.1x developer so you're sure you're getting the better end of the deal ;).
Speaking as a 10x dev, this is truth. I have felt underpaid most of my career. After 30 years, I don’t give as much at work anymore. I bought a farm and most of my energy goes there instead. I suggest wishing for a healthy balanced life. No happiness comes from being undervalued and underutilized.
Win the lottery and become a 10x dev and maybe he'll dream about it.
And even before it happened. But stated afterwards.
Why would you ever want to become a 10x dev instead of winning the lottery?
In my reading I have read of several such occurrences, and experienced one myself. On 2 Feb 1990 I fell asleep in front of the TV and dreamed I was a journalist in Cape Town, South Africa. There was buzz about a possible speech by F.W. de Klerk in front of Parliament. I was concerned that I needed a snack on the way, and hoped that the gov't would provide donuts. Then I woke up and CNN was nagging me that de Klerk was about to address Parliament. The subject was South Africa transitioning out of apartheid.
Again sleeping with the TV news channel turned on?
Daily horoscope
- Pisces: A difficult day despite the expansion of your living space
- Scorpio: ...
I stayed at the hotel this September. My first thought was "oh, my, there is a breakfast area right there on a ground floor, and it is starts buzzing right from 6am!”. Fortunately, the bang happened 20 mins before.
Interestingly, looking at the tank from my room, I never thought about the scenario when it breaks. I thought "engineers must put a lot of extra margin when constructing this". Turned out I was wrong.
So Long, and Thanks for All the Fish
Wow, what a shock! I stayed here in 2017 and often looked up at the aquarium whilst having a coffee or beer in the foyer.
I've stayed there as well for two nights a few years ago, it was a great attraction. Really, really large too - a million liters of water, five stories tall or higher, I don't even remember.
That's a real shame only a few fish survived. It's fortunate only two people hurt. That looks nasty from the picture. Maybe next time less brittle acrylic. Off the top of my head a 14 m high tower of water - there would have been approx 20 psi at the bottom of the tank.
> there would have been approx 20 psi at the bottom of the tank.
[1] agrees with you at 19.9psi
[1] https://www.engineeringtoolbox.com/hydrostatic-pressure-wate...
Just fyi - acrylic is actually less brittle than glass.
The proper matetial to use is transparent aluminium [0] though.
To be clear ... less brittle acrylic isn't glass.
Those fish must have taken a battering
Any fish that got flushed out will be lost, they need things to be 'just so'. I once helped clean up at a friends place who had 30 aquariums with thousands of fish after the power went out longer than his UPS could provide it. The mess was sickening. He never had another tank after that and it was his life's passion.
It feels in this case that a lot of fish were killed for no reason at all. I am surprised at how much this annoys me.
Interesting to think about. On the one hand, it's no different than any of the random stuff that happens to fish in the wild, or wildlife in general. Being killed for no reason at all is the default in nature; humans build societies and civilizations and develop technologies in large part to avoid it.
On the other hand, this feels especially sad for some reason.
We have an industrial unit which has a mice problem. Every time I go to B&Q (home hardware store for non-UK folk) with the intention of buying mice traps, I just can’t push the button. These mice are destroying our stock, but I just cannot do it. I would be a terrible fisherman.
Have you considered outsourcing? To a cat (or cats) or a pest control company. The pest control company will probably check and close off opportunities for mice to enter the unit, which cats won't do, so you might want to consider retaining both options.
Warehouse cats can be nice warehouse companions too (depending on what happens in the unit).
I've had to do some mouse removal work in my forest adjacent home, and it's not pleasant, but neither is having mice around.
We took our cat in, but she absolutely hated it. Then we thought she escaped for a few hours until we found her expertly hiding underneath some machinery.
In Costco they sell this cat food called ‘Maintenance cat’. Maybe we need one of those cats.
Yeah... around here shelters separate out 'barn cats' from 'pet cats', barn cats are tolerant of people but not really socialized to appreciate people. Rather than taking an existing pet cat and putting him or her to work, I'd try adopting a barn cat and putting them to work. Often, barn cats do retire and become pet cats towards the end of their life, if circumstances allow.
Of course, cats can cause a different sort of trouble than mice. :D
Barn cats are pocket sized tigers. I've seen one filet a grown up guy that tried to evict it. He looked like he'd been run over by a harvester.
I'm dying at the idea of a maintenance cat. In my mind he's wearing little overalls and carrying a wrench.
> I would be a terrible fisherman.
To be fair, you have to catch and release most fish in the UK which, whilst annoying for the fish, doesn't seem to do them much harm since there's e.g. a whole bunch of 30y+ old carp that keep getting caught.
You're allowed to keep a certain set of game and sea fish if they're big enough and from the appropriate place.
You can get catch-and-release mice traps, and then dump them in a field or on a competitor.
I like this idea. Maybe I will let them breed and multiply first actually!
With 30 tanks he was probably breeding the fish
No, just a somewhat extreme hobby.
For avoidance of doubt, I was talking about the hotel, not your friend.
For how much longer than his UPS could provide it?
A couple of hours only.
I'm sorry for your friend's loss and for the lost livestock, but it seem like it was simply a ticking time-bomb.
If your friend had 30 tanks and thousands of fish, they should have had a more involved backup plan that involved a dedicated generator in addition to a UPS. A small generator would have been a tiny fraction of the materials and livestock costs of running a setup like that.
It was the work of a lifetime. Power here has been so reliable that people forget that it can fail, and even though he was somewhat prepared it turned out not to be enough.
Agreed though that it was a ticking time bomb. As for better backup plans: even autostart generators for data centers can fail when you need them most. Backup plans end up with more and more layers until you think you've got it all and then some little oversight will get you. In his case he probably could have done more but that's only because we're looking at it after the failure, for decades it worked.
Most people in cities in the US have never experienced a power failure that lasts longer than an hour or so (and many places have NEVER had one). It's understandable that people don't think much about it.
Though the moment the UPSs hit 50% you might try to run to Home Depot and grab a generator, but by that time they'd all be sold out.
That's the UK you're thinking of, not Germany.
That is lot of water. A thousand tonnes. It could do lot worse.
Imagining a 10m cube gives a good idea of the amount.
This is crazy. I've been there a few times as the hotel is a popular spot for conferences (likely in part because of the attraction of the aquarium - I wonder if it will continue to be so popular a venue now). The aquarium was absolutely huge, I can't imagine what it must have been like seeing it burst.
Sadly I never availed of the elevator ride through the aquarium.
Just to add context we could be talking easily about more than $100,000 lost only in the fishes. The materials and pumps of the aquarium should be much worse.
After the strange coup try in Germany the last week, I wouldn't discard still that is not another destabilization attempt by some hypothetical agent. Weren't cameras set around the Hotel hall?
> After the strange coup try in Germany the last week, I wouldn't discard still that is not another destabilization attempt by some hypothetical agent.
How would that work? Is this site important enough to destabilize the country?
Only two people injured after a million liter water wave was a miracle. Could have been much worse.
But I'm probably just hypothesizing too much [again] while trying to analyze the case. It just feels strange coupled with the last long chain of strange events happening right now. To be fair, twenty years are a lot of time for an acrylic tank.
Andreas Tanschus interview: https://www.youtube.com/watch?v=BZXfuLEAEEs
Wow, how do you make pieces of glass that size?
It was manufactured in 2004 by a US company, "International Concept Management": https://icm-corp.com/
(side note: what a weird name for an aquarium manufacturing and design company)
According to https://www.newlift.de/details-referenzen/aquadom.html , several companies were involved. Reynolds Polymer Technology, Inc. provided the acrylic windows: https://www.reynoldspolymer.com/projects/aquadom/ .
ICM has already removed AquaDom from their portfolio page https://icm-corp.com/portfolio/ , but a cached version (for now at least) exists at https://webcache.googleusercontent.com/search?q=cache:XGSNC7... .
Where do you have the year from? The aquarium was opened 2003 after several years of building. And seeing it now, two weeks ago it even had its 19th "birthday". Speak about bad timing.
uuuups... they better lawyer up...
That's Germany, not the US.
yes they better lawyer up in Germany, correct
Not sure about Germany but in the UK the designers would be unlikely to still be liable anymore under the original contract to design this, liability under the contract would be up to 12 years from when the work under the contract was completed. They might be liable in tort for professional negligence but it's much harder to prove that this has occurred especially after 20 years. More likely the company that was under contract to inspect/maintain this will get hammered.
Or the one that modified it, assuming that's not the one that originally built it.
It looks to me as if they're actually a lot of smaller pieces put together, but maybe I see it incorrectly. Maybe one day, architects will stop designing things that are structural liabilities, or engineers actually get to say no to it before construction starts.
I don't understand your comment. Architects did not design this fishtank, engineers did, ones that specialize in such constructions. Whether or not the design was at fault or there were construction or maintenance issues or the tank was modified out-of-spec, whether there was damage due to the recent renovations are all open questions.
Structural engineers take their work very seriously, much more seriously than your typical software person and you can bet that any and all lessons learned from this incident will be incorporated into future designs. They don't just slap stuff together for the laughs and call it a day.
Incredibly unlikely for any part of the structure to have been designed by an architect, most likely a highly specialist subcontractor design item. Our insurance would not cover it and it is illegal for architects to practice without insurance in many EU countries. The closest any architect would get to this is to go to a big fish tank company and say I want a big fish tank with diameter x and height y, can you do it and how much will it be...
They could make it from concrete.
They should use transparent aluminium https://en.m.wikipedia.org/wiki/List_of_Star_Trek_materials#...
Modern sapphire glass (Al₂O₃) is basically transparent aluminium, and it is very strong. Probably way too expensive to make an aquarium out of it, though!
This is an amusing line of inquiry. Sapphire is growing in popularity for microchips. I found a source for single-crystal sapphire ingots... they only go up to 8 inches (~20cm) in diameter, about 60mm long. This tank was about 11 meters in diameter, 25m long. Scaling that up would be quite the project.
I mean, you could probably do chemical vapor deposition, but it wouldn't be a single crystal so what's the point?
"list of Star Trek materials"?
Says a guy named "Cthulhu"? Obviously, he is being humorous.
I've been there so many times, every time I went to Berlin, sad news.
It looked pretty cool and was a good place to bring people who didn't know Berlin after a visit to the beautiful Pergamonmuseum, which is 5 minutes walk away.
But I went on the elevator only the first time, it was clear that that wasn't a good idea at all.
Water pressure is very high over 60cm tall for a standard glass panel. This is the reason to not have really big home aquariums for hobbyists in the market, unless you build it directly. They grow in surface instead to be taller
Now radisson will have to discount the room prices, once main attraction is gone...
I bet it stinks for months too
I can only imagine the smell. I remember once having a small aquarium as a kid and it had that 'fishy' smell to it. The whole place must smell like that now.
From the article: “None of the animals inside the saltwater aquarium, which contained clownfish, teira batfish and palette surgeonfish, survived.”
:(
This sounds like the plot of a John Irving novel.
Sadly I don't read German, was anyone injured?
2 people, 1500 fish
2 people got injured and mostly all fish are dead...
Humans are horrible creatures.
It was an accident though, surely, and they didn't mean to hurt the fish.
You mean, they put the fish behind glass in a artificial habitat, which apparently was not built well enough to not break. And you still think humans were just well-meaning? How would you feel if someone took you and your family, and put ya all behind glass, for others to watch? Oh, and there will be an elevator going through your new habitat? Still just fine? I told ya, humans are horrible creatures, they dont even see the errors of their own way.
IMHO there should be a DE/German tag in the title.
edit: title has been edited since this comment
The root cause of this was that the hotel was forced to lower their heat due to energy sanctions. Reduced heat caused the aquarium to contract which contorted the structure, eventually causing the failure.
Citation?
You're also ignoring the thermal mass and physical pressure of a million liters of water.
They're pulling that "info" from the conspiracy theorist website zero hedge.. that it conveniently aligns with that site's support of Putinist Russia should be noted. The German law limits public space heating to 67º which doesn't seem like it should be nearly enough to cause this kind of failure..
I would also think that 1,500 tropical fish need the water to be maintained at a certain temperature to keep them alive.
If anything, the water tank was heating the room instead of vice versa.
How do they make such a huge cylinder?
Take a large sheet of acrylic, warm it, bend it by warming it and applying pressure. If the circumference is large take multiple ones. Glue ends together, glue in base plug.
They found Nemo... everywhere...
For some reason "A Fish Called Wanda" comes to mind!
Or maybe that should be "Fish go Wandering"?!
Collateral damage from the launch of Cameron's Avatar 2.
“So long, and thanks for all the fish.”
— This Aquarium, probably
Came here for this reply
Horrible
How come there's no footage?
I think it could take a little while to come out, but I'm sure they had cameras in the lobby. It did just happen this morning after all. The building's structural integrity is being checked.
Exactly - the security cam footage takes a few days to be released if the company wants it, or a few weeks to leak quietly if they don't.
At 6 AM you're not going to have many people standing around with cell phone cams for it (and anyone around when the giant tank starts making horrible noises would be hopefully smart enough to run for higher ground).
From the guidelines:
> Off-Topic: Most stories about politics, or crime, or sports, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic.
HN really needs a European mod to maintain the quality of this board.
I think large-scale engineering failures in other disciplines are always of interest here.
It's interesting only if there's a detailed report on the reasons. Otherwise this piece is news is just a "oh", instead of a "a-ha".
I think we're richer for having this type of content, not least because someone has posted elsethread that the early signs point to material fatigue. The system works as far as I can see, and I think we're some way off the front page of HN being flooded by TikToks.
> not least because someone has posted elsethread that the early signs point to material fatigue
I don't mind it being posted here, but to be fair that is just repeating what one politician is saying: "'Of course, the investigation into the cause has not yet been completed, but the first signs point to material fatigue,' said Berlin Interior Senator Iris Spranger (SPD) of the German Press Agency."
Now if someone were to point at some image and explain why that makes them think it was fatigue that would be great.
I don’t know about TikTok, I just know this post was submitted by someone with 50 karma originally pointing to a German radio station news site, in German. It was only changed to the Guardian later, perhaps by a mod.
They'll start on the report after they finish mopping 1000 m^3 of water i guess.
This is more interesting than the "look what I cloned in Rust" posts at the least.
What exactly have we learned that’s valuable from this news?
> What exactly have we learned that’s valuable from this news?
A lot. It depends on your personal preferences.
If you, as me, are interested in building aquariums and, as me, has watched with disbelief a couple of thick glass panes becoming arches by just 50cm of water, the system built and the planning put on it should be awesome enough. This tank worked for 20 years than is more than most hardware.
If you (as many people here) are interested in space and Mars colonization, you need seriously consider learning the art of keeping fishes in huge tanks. Aquaculture skills will be vital to keep a colony out of the earth.
To start, is one of the better methods known to produce quality food fast to keep your people feed. Some fishes are particularly well suited for space travel, and can even travel safely dehydrated in a paper envelope.
Even more important, tanks with aquatic organisms will be basic to recycle the residues in your small city. Water will be precious stuff and higher tanks allow a much better evaporation control.
You don't want one million litters flood happening in your spatial base so there is a big lesson here for us to learn
At least one person learnt of the existence of "static fatigue". Which I'd count as a win, personally.
And that you got away ;) Great comment upthread by the way.
I mean as long as we're quoting (and breaking) the guidelines:
> Please don't complain that a submission is inappropriate. If a story is spam or off-topic, flag it. Don't feed egregious comments by replying; flag them instead. If you flag, please don't also comment that you did.
(someone flag me, I can't flag myself)
There's an engineering angle here that I think a lot of us probably find interesting?
I guarantee you car crashes has more engineering angles than this. There's not even a post-mortem here.