You know Herman, I was looking at some recent structural engineering reports from the Technion, and it really struck me how much our definition of safety has had to evolve over the last few decades. It is not just about having a roof over your head anymore; it is about the specific density and reinforcement of that roof. We have moved from a world where a "sturdy building" meant it would not fall down in a storm, to a world where we are calculating the exact joules of energy a single room can dissipate.
It is a constant arms race between protection and penetration, Corn. Herman Poppleberry here, and you are absolutely right. The physics of shelter design is essentially a study in energy dissipation and material science. When we talk about modern civil defense, we are asking: how much kinetic and thermal energy can a structure absorb before it fails? It is a grim topic, I will grant you that, but the engineering behind it is honestly some of the most sophisticated work being done in civil engineering today. We are talking about high-performance concrete, complex rebar geometries, and blast-wave dynamics that would have been unthinkable for residential construction forty years ago.
It really is. And that leads us directly into what we are exploring today. Today's prompt from Daniel is about a choice many people in Israel are facing right now, especially given the heightened tensions and the technological shifts in the region over the last few years. Daniel is asking about the trade-offs between an apartment safe room, known as a Mamad, and those deep, underground car parks that have been designated as public shelters. He is specifically looking for the engineering perspective on where the safest place to be is during a heavy ballistic missile attack.
It is a heavy question, Daniel. And before we dive into the structural analysis, I want to reiterate that disclaimer we always give when we talk about life-safety issues. We are looking at this through the lens of engineering and data, but always, always follow the live instructions from the Home Front Command. They have the real-time data, the intelligence on incoming threats, and the expertise that we do not. But from a structural standpoint, Daniel is hitting on a debate that has been circulating in engineering circles for a while now. It is a choice between proximity and mass. It is the "Home Shelter" versus the "Fortress" debate.
Right, and before we get into the weeds, we should probably define the terms for anyone not familiar with the Israeli system, because the terminology is very specific. We are talking about three main types of protection. There is the Mamad, which is an acronym for Merchav Mugan Dirati, or apartment protected space. Then there is the Mamak, the Merchav Mugan Komati, which is a shared protected space on each floor of an apartment building. And finally, the Miklat, which is a more traditional bomb shelter, often located in the basement or even completely underground and separate from the building.
The Mamad became the gold standard after the nineteen ninety-one Gulf War. The idea was born out of a very specific trauma. During the SCUD missile attacks back then, people were getting injured not just by direct hits, but by the time it took to get to a communal shelter. People were being caught in stairwells or in the street. The Mamad brought the shelter into the home. It is a reinforced concrete room with a heavy steel door and a gas-tight window. But the key thing to remember, and this is where Daniel's question gets interesting, is that the Mamad was originally designed primarily to protect against shrapnel and blast waves from smaller rockets or chemical threats, not necessarily a direct hit from a heavy ballistic missile.
And that is the crux of the anxiety, isn't it? When you see the size of a modern ballistic missile warhead—something like a Fateh-one hundred ten or a similar class of projectile—you are talking about five hundred kilograms of high explosives. A Mamad has walls that are typically twenty-five to thirty centimeters thick. That is a lot of concrete, but compared to a direct hit from a half-ton of explosives traveling at supersonic speeds? It feels like a mismatch. It feels like bringing a leather shield to a tank fight.
It is a mismatch if you look at it as an isolated box. But this is one of those things we talked about back in episode six hundred one when we looked at the engineering of safe rooms. A Mamad is not just a room; it is part of a vertical column. In modern Israeli apartment buildings, the Mamads are stacked directly on top of each other, from the foundation all the way to the roof. This creates a reinforced concrete core. It is actually the strongest part of the building's skeleton. Think of it like the spine of the building. The rest of the apartment—the living room, the kitchen—is essentially "flesh" hung onto this concrete spine.
So, even if the rest of the building takes a hit and the "flesh" is stripped away, that "column of survival" is meant to stay standing. I remember you explaining that. But Daniel's point is about the overhead protection. If a missile is coming from above, a Mamad on the fifth floor only has the roof and maybe a few other Mamads above it. Compare that to a designated underground car park. Some of those are three or four levels below the surface. You are talking about meters of reinforced concrete and earth above you. From a pure "how much stuff is between me and the explosion" perspective, the car park seems like the clear winner.
Mass is the ultimate defense against kinetic energy. There is no getting around that. If you are in the bottom level of a four-story underground parking garage, you have an incredible amount of material between you and the sky. Structurally, that is almost always going to be superior to a Mamad in terms of surviving a direct overhead impact. The concrete slabs in those garages are incredibly thick to support the weight of the building and the soil above. We are talking about a level of protection that approaches military-grade bunkers. In engineering terms, we call this "overburden." The more overburden you have, the more the energy of the blast is attenuated before it reaches the occupied space.
So, on paper, the car park wins. But Daniel mentioned a big caveat: flammable vehicles. And I think that is a massive "UX of survival" issue, like we discussed in episode eight hundred twenty-four. You are trading the risk of a structural collapse for the risk of a secondary disaster. If a missile hits the building above, or if there is a breach, and you have hundreds of cars with gasoline tanks and, increasingly, large lithium-ion batteries? That is a nightmare scenario for a confined space. You might survive the blast only to face a fire that you cannot escape.
It really is. Underground fires are notoriously difficult to fight. The heat buildup is intense, and the smoke has nowhere to go. Most of these car parks have massive ventilation systems, but those systems require power. If the building's infrastructure is compromised by a strike, those fans might not be spinning. You could end up in a situation where the structure holds perfectly—the ceiling doesn't even crack—but the environment inside becomes unsurvivable due to smoke inhalation or heat. Lithium-ion battery fires are particularly nasty because they produce their own oxygen as they burn. You cannot just smother them.
And then there is the time factor. This is something the Home Front Command emphasizes constantly. In Jerusalem, where Daniel is, you might have ninety seconds of warning. In other parts of the country, it is sixty, thirty, or even fifteen seconds. If you live on the eighth floor, you are not making it to the third level of an underground car park in ninety seconds, especially not with a toddler like Ezra. You would be caught in the stairwell or the elevator, which is the most dangerous place to be. The elevator can become a trap if the power goes out, and the stairwell, while reinforced, is often a chimney for smoke and debris.
That is the "proximity versus protection" trade-off. The Mamad is five steps from your bed. You can be inside and have the door bolted in ten seconds. That means you are protected from the ninety-nine percent of threats that are not direct hits. Remember, the vast majority of injuries in these attacks come from flying glass, shrapnel, and blast waves from nearby impacts, not from the building you are in being leveled. The Mamad is nearly perfect at stopping those threats. It is designed to handle the "overpressure" of a nearby explosion.
So, it's a bit like a seatbelt versus a roll cage. The Mamad is the seatbelt you wear every time because it's right there and protects you from the most common dangers—the sudden stops and the minor collisions. The underground car park is like a full roll cage and a fire suppression system, but it doesn't help you if you can't get into the car in time. But let's look at the engineering debate Daniel mentioned. He said structural engineers are still debating if a Mamad can actually withstand a ballistic impact. What is the latest on that as of early twenty-six?
There was a lot of soul-searching after the conflicts in twenty-one and twenty-three, and even more so after the long-range threats we saw in twenty-four. We saw some instances where very large rockets caused significant damage to older structures. The debate isn't so much about whether the concrete will hold—we know a direct hit from a heavy ballistic missile will likely penetrate thirty centimeters of concrete. The laws of physics are pretty clear on that. The debate is about the "systemic" failure versus "localized" failure.
Meaning the whole building coming down versus just one room being destroyed?
If a missile hits the top of the building, does the Mamad column hold? Recent simulations and real-world data from the last two years suggest that the column design is incredibly resilient. Even if the outer walls of the apartments are blown away, that central core tends to remain standing. It is a "fail-safe" design. But there is a new concern that engineers are focusing on: the door and the window. The steel door of a Mamad is designed to withstand a certain amount of blast pressure—typically around one point two bars of overpressure. A large ballistic missile exploding nearby can generate pressures far exceeding that.
So the room stays intact, but the door becomes a projectile? That sounds like a terrifying failure mode.
Or the frame buckles. There have been updates to the building codes—I think it was Amendment twenty-eight to the civil defense regulations—that increased the requirements for the thickness of the steel and the way the frames are anchored into the concrete. If you are in a building built in the last five or six years, your Mamad is significantly tougher than one built in the nineties. The reinforcement density—the amount of rebar per cubic meter—has gone up. But Daniel's point stands: it is still not a bunker. It is a "protected space."
Let's talk about the car parks again. Daniel mentioned he was actually in one while recording his prompt. When the Home Front Command designates a car park as a shelter, what are they actually looking for? They aren't just saying "any basement will do," right? Because I have seen some basements that look like they would crumble if you sneezed too hard.
No, not at all. A "designated" car park has undergone a specific certification. Engineers look at the slab thickness—usually looking for at least forty to sixty centimeters of reinforced concrete for the first level, and more for deeper levels. They look at the number of support columns and the "punching shear" resistance. Crucially, they look at the ingress and egress points. Are there at least two separate ways out? They also look at the ventilation. In many of these newer buildings in Jerusalem and Tel Aviv, the car parks are built with dual-purpose infrastructure. They have blast doors that can be rolled shut, and the ventilation systems have CBRN filters—that is Chemical, Biological, Radiological, and Nuclear filters.
So those are essentially massive public bunkers that just happen to have cars in them during peacetime. It is a clever use of urban space, but it brings us back to those cars. If I am Daniel, and I am standing in a designated car park, I am looking at a row of Teslas and thinking about thermal runaway.
Precisely. And in those cases, the fire risk is mitigated—at least in theory—by heavy-duty sprinkler systems and fire-rated walls between sections. But Daniel's concern about the "flammable vehicles" is still valid. Even the best sprinkler system can struggle with a lithium-ion battery fire. If I were making the choice, I would be looking at the specific level of the car park. Level negative one is basically just a basement with a bit more concrete. Level negative four? Now you are talking about serious protection. At that depth, you are shielded by the mass of the entire building above you.
But then you are back to the ninety-second dash. It feels like the Mamad is the "rational" choice for most people because it guarantees you will be in a protected space when the impact happens. The car park is a "high-stakes" choice. If you make it, you are safer. If you don't, you are much, much worse off. You are caught in the open or in a vulnerable stairwell during the most dangerous moment.
It is a classic risk-reward calculation. If you have a high degree of confidence that you can reach the car park in time—maybe you live on the ground floor or the first floor right above it—then the car park offers superior protection against the absolute worst-case scenario, which is a direct hit on your building. But for someone like Daniel, with a young son, the chaos of trying to get down several flights of stairs with a child during a siren? The risk of a fall, a panic-induced mistake, or getting stuck in a crowd might actually be higher than the risk of a direct missile hit on his specific apartment.
That is a great point. We often forget the "human factor" in these engineering problems. A shelter is only as good as your ability to use it. If the path to the shelter is dangerous, the shelter's structural integrity is irrelevant. I think back to episode seven hundred ninety-three when we discussed the psychology of the siren. The panic can be as dangerous as the projectile. We have seen people get seriously injured just from falling on the way to a shelter.
And there is another technical detail we should mention regarding the Mamads. The "column" effect we talked about isn't just about vertical strength. It is also about the "shadow" it casts. If a missile hits a building at an angle, the reinforced concrete of the Mamad column can actually shield the rest of the building to some extent. It absorbs a huge amount of the energy and prevents the "pancake" collapse that you see in unreinforced masonry buildings.
So, ironically, by being in your Mamad, you are also contributing to the structural survival of your neighbors' homes. You are part of the building's defense system.
In a way, yes. It is a collective defense mechanism built into the architecture. Now, Daniel asked about the "ongoing debate" among engineers. One of the things being discussed right now is the "spalling" effect. This is a big one. Even if a missile doesn't penetrate the wall of a Mamad, the shockwave of the impact can cause the concrete on the inside of the wall to flake off and fly around the room at high speeds. It is like a secondary shrapnel effect.
Wait, so the wall stays standing, but the inside of the wall turns into bullets?
It's called "scabbing" or "spalling." The compression wave hits the outer face, travels through the concrete, and when it hits the inner face, it reflects as a tension wave. Concrete is great at compression but terrible at tension, so the inner surface just snaps off. That is why newer Mamads are often finished with a specific type of flexible plaster or even a thin layer of carbon fiber or steel mesh behind the finish. It is designed to catch those concrete fragments. If you are in an older Mamad, one of the best things you can do—and this is a very practical takeaway—is to make sure you don't have heavy shelves, mirrors, or glass-framed pictures hanging on the reinforced walls.
Because they become projectiles the moment the wall vibrates from an impact. It's not just about the missile; it's about the physics of the room itself.
The wall might hold, but the stuff on the wall will not. In an underground car park, you generally don't have that issue because the walls are often unfinished concrete and you are not sitting right against them. But you have other issues, like the potential for dust and debris from the ceiling. If a building above takes a hit, the car park might not collapse, but it will certainly shake, and you could have a lot of non-structural material falling.
You know, we have been talking about this as a binary choice, but for many people, the choice is made for them by their building's age. If you live in a building from the nineteen seventies, you don't have a Mamad. Your only choice is the stairwell or a public shelter. In that case, the designated car park is a godsend. It is a massive upgrade over a stairwell.
Oh, a huge upgrade. The stairwell is the "better than nothing" option. It provides some protection because you have the mass of the building's core around you, but you have no protection from blast waves coming up or down the stairs. A designated car park with blast doors is a different league entirely. It is a true shelter. The key is knowing the difference between a "basement" and a "designated shelter." If the Home Front Command has put a sign on it, it means an engineer has signed off on its ability to withstand specific loads.
So, if we were to summarize the engineering perspective for Daniel, it sounds like the car park is the "Hardened Bunker" option, while the Mamad is the "Distributed Survival" option.
That is a good way to put it. The car park is objectively stronger against a direct, high-energy impact. It has the mass. But the Mamad is part of a system designed to maximize the number of survivors across a population by ensuring that almost everyone can reach some level of protection instantly. It is about the statistical probability of survival.
It is the difference between a high probability of surviving a medium-threat and a lower probability of reaching a high-protection zone. For a ballistic missile, which is a high-threat, the car park is the engineering answer, but the Mamad is the practical answer.
And we have to talk about the "flammable vehicles" again because I think that is the biggest psychological barrier. If you are in a car park and you hear a massive impact above you, your first thought is going to be "Is there a fire?" and "Can I get out?" The Mamad has a window. It sounds counterintuitive, but being able to see out, even through a heavy steel shutter, and knowing you have a clear exit into your own home is a massive psychological advantage. It prevents that feeling of being buried alive.
Right, the "entombment" fear in an underground car park is real. If the ramps collapse or the doors jam, you are in a very difficult spot. In a Mamad, you are on an external wall. Even if the building is damaged, search and rescue teams can reach you from the outside. That is actually one of the design requirements for Mamads—the window has to be accessible for rescue. It is a double-edged sword because the window is a weak point, but it is also a survival point.
That is a huge point, Corn. The Israel National Fire and Rescue Authority has specific protocols for Mamad rescues. They can use cranes and external cutting tools. Rescuing five hundred people from the fourth level of a collapsed underground car park? That is a multi-day operation. It requires heavy mining equipment. So, when you look at the "post-impact" phase, the Mamad actually has some significant advantages.
So, when Daniel is sitting there in that car park, he is surrounded by a lot of concrete, which is good. But he is also in a complex environment with fuel, batteries, and limited exit points. If he is at home with Hannah and Ezra, and the siren goes off, the Mamad is likely the superior choice simply because of the speed and the post-impact accessibility. It is the "graceful failure" model.
I agree. Unless the car park is literally twenty seconds away and has clear, multiple exit paths that are unlikely to be blocked by debris, the Mamad wins on the "human factor" scale. But from a pure "will this slab stop a one-ton missile" perspective? The car park is the winner. It is the brute force solution.
It is fascinating how these two different philosophies of protection exist side-by-side. One is about brute force mass, and the other is about integrated, systemic resilience. It reminds me of the earthquake discussions we had in episode six hundred two. You can't always stop the force, but you can design a system that fails in a way that keeps people alive.
A building with a Mamad column is designed to fail gracefully. The outer skin might fall away, but the core stands. An underground car park is designed not to fail. But if it does—if the impact exceeds its design limit—it fails catastrophically. There is very little middle ground in a deep underground structure.
That is a stark way to put it. "Failing gracefully" versus "not failing until it's a catastrophe." I think that really helps frame the choice for Daniel. For most people, in most scenarios, you want the system that fails gracefully and keeps you accessible to rescuers.
And it's worth noting that the Home Front Command's advice—the "Mamad, Mamak, or Miklat" hierarchy—is based on decades of data. They have analyzed every major conflict since ninety-one. They know the statistics of where people get hurt. They aren't just guessing. They are looking at the probability of a direct hit versus the probability of being injured while running for a shelter. The "stay put" or "go to the nearest protected space" advice is mathematically the soundest way to save the most lives across a whole city.
It is a numbers game. And when you are talking about the safety of your family, like Daniel is with Hannah and Ezra, you want the best odds. The best odds usually involve being in the strongest possible room that you can reach without panic.
Well said. And hey, for Daniel and everyone else listening, there is some interesting research coming out about "hardening" your existing Mamad. Beyond just clearing the walls, there are new types of blast-resistant curtains and internal coatings that can further reduce the risk of spalling. There are even companies now that offer secondary reinforcement for the door frames. It is worth looking into if you live in an older building or if you are in a high-risk area.
That is a great practical tip. It is about layers of protection. No single thing is a magic shield, but when you add up the reinforced concrete, the stacked column design, the blast door, and a clear interior, you are significantly better off than almost anywhere else in the world during a missile attack.
And don't forget the "Safe Room UX" we talked about. Keep it stocked. Keep it comfortable. If it's a place where Ezra feels safe and has his toys, the transition during a siren is going to be much smoother. If the child isn't resisting, the door gets closed faster, the stress levels stay lower, and everyone is safer. The engineering of the room includes the people inside it.
The psychological prep is just as important as the structural prep. If you are not panicking, you are making better decisions. And speaking of decisions, I think we have given Daniel a lot to chew on here. It is not an easy choice, but understanding the engineering behind it—the mass of the car park versus the systemic resilience of the Mamad—is the first step to making an informed one.
It is about understanding the "why" behind the walls. Whether you are under three meters of concrete in a car park or inside your apartment's reinforced core, the goal is the same: to buy time for the danger to pass. The engineering is there to give you those extra seconds or those extra inches of protection that make the difference.
Well, this has been a deep dive into some very literal "heavy" topics. Daniel, thank you for the prompt. It is something that is clearly on the minds of so many people right now, and it is a perfect example of how "weird" prompts can lead to very serious and necessary discussions.
If you found this discussion helpful, or if you have your own questions about the engineering of everyday life—or the engineering of survival—we would love to hear from you. You can reach us at show at my weird prompts dot com.
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It really is. Alright, I think that wraps it up for today. Stay safe out there, stay curious, and we will talk to you in the next one.
This has been My Weird Prompts. See you next time.
Bye everyone.
