Anyone who likes post-apocalypse movies knows what a house that’s been exposed to a nuclear blast looks like – shattered walls blown down to a few feet high, charred timbers and a fire-gutted interior. The skeletons of its occupants might even be draped artistically over a pile of rubble.
Pictures of Hiroshima and Nagasaki after they were bombed show exactly this kind of total destruction, so it’s natural for a lot of people to be pretty resigned about nuclear war.
If they can cause that sort of devastation, surely there’s no chance of survival anyway? Isn’t it better to just get it over with quickly?
In a word, no.
The blast from a nuclear weapon is incredibly powerful, but it still obeys the laws of physics; the intensity of the destruction drops off rapidly as you move away from the exact center of the explosion – Ground Zero. It doesn’t drop in a straight line either, but roughly follows the inverse square law. That basically means the effects of the weapon fall by the square of the distance from Ground Zero; if you’re twice as far away the effects will be about a quarter as destructive, and if you’re three times as far away they’ll be one-ninth as destructive.
These figures aren’t rock solid, and can vary depending on the height the weapon explodes at and the shape of the ground, but they’re a pretty good rule of thumb. Even with a very large weapon, you don’t have to be that far away from it for the level of destruction to fall from total to survivable – and, even in a full-scale attack, huge parts of the country would escape the immediate effects completely. So if the risk of a nuclear attack increases, unless you live in a major city or right beside a strategic target, it’s definitely worth preparing your home to give it – and you – the best chance of survival.
If you’re going to prepare for a nuclear attack, first you need to know what the dangers are. When the warhead detonates there are basically five ways it can kill you:
- Thermal pulse – A very intense flash of heat and light
- Blast – Overpressure and high winds
- Prompt radiation – A pulse of X-Ray and gamma radiation
- Residual radiation – Alpha and beta radiation released by the ground around Ground Zero
- Fallout – Radioactive particles scattered by the explosion
First, forget about the prompt radiation. This is a single brief pulse, lasting a few seconds, and its intensity falls off by the inverse square law. If you’re more than 3,000 feet from the explosion you won’t pick up a dangerous exposure. In other words, unless it’s a very small weapon, if you’re close enough to have to worry about prompt radiation the thermal pulse or blast will already have killed you anyway.
Residual radiation is more of a problem, but it’s an easily avoided one. When a nuke goes off on the surface, or in the air but low enough for a significant gamma pulse to hit the surface, the ground itself will become radioactive. It emits alpha particles, which can be stopped by a gas mask and heavy clothing, and more dangerous beta particles, which will penetrate the body of a vehicle. Residual radiation can be dangerous weeks after the blast. Luckily, you don’t need to expose yourself to it. Simply don’t go near craters or areas of complete destruction.
So we’re left with three things you need to protect against: Thermal pulse, blast and fallout. With the right preparation you can make your home much more resistant to all of these. Here’s how to do it.
A nuclear weapon releases a huge amount of energy, and about a third of it comes out as electromagnetic radiation. This radiation covers a wide spectrum, from gamma and X-Ray through UV, radio frequency, visible light and infra-red, and it’s extremely intense. All this energy delivers a lot of heat; anything close to the explosion will be heated enough to turn it into plasma, and even eight miles from a one-megaton airburst the energy intensity is high enough to cause third-degree burns. Obviously that’s also enough heat to start fires, and as you get closer to the explosion the risk will go up geometrically. The good news is, if you take the right precautions your home can be safe from fire at a distance where an unprepared one would burn.
First, clear away anything flammable from around your home. Dead vegetation will flare up easily and scatter sparks; even if the flash from the weapon doesn’t burn your house down, burning leaves can do it. Inside, remove anything flammable from windowsills and check your curtains. Light or net curtains need to be taken down, but if you have heavy, lined ones leave them up and closed – they’ll help protect against flying glass if the windows break.
Next, get some white emulsion paint and give the exterior of all your windows a coat. People laugh at this advice, but it can make a huge difference. White paint will reflect most of the pulse’s energy and keep it out of your home; without it there’s a very high risk of fires starting inside. Some people argue that the blast will break your windows anyway, but they’re wrong. First, in the right conditions the thermal pulse can start fires a lot further away than the blast can break windows. Secondly, the blast wave is very fast – the shock front can propagate outwards at over three miles per second – but the thermal pulse is traveling at the speed of light. Even if the blast arrives before the flash has faded you’ll still keep a lot of that thermal energy outside.
If you have a bit more time, paint as much of your house white as you can. Start on walls that face towards likely nuclear targets – if there’s an airbase five miles away, do that side first. Your aim here is exactly the same; to reflect as much thermal radiation as possible. Every bit of energy you can reflect back off your walls reduces the risk of a fire.
Sort out as many fire extinguishers and buckets of water or sand as you can. Keep in your fallout room (we’ll discuss that soon). Cover water buckets; that way you can use them for drinking, too. Finally, if you hear an attack warning or you have to leave home for a while, turn off the gas and electricity at the mains. That will cut the risk of damage causing a fire.
Blast is the hardest effect to defend against. The explosion’s shock front will push a fast-moving wave of highly compressed air along with it; close to the explosion this move at three or four times the speed of sound, and it’s very destructive. The good news is human bodies can survive overpressure up to about 30psi, and anything close enough to face that amount of pressure will almost certainly be vaporized by the thermal pulse. The bad news is that even heavy concrete buildings won’t survive much above 20psi, and 5psi is enough to collapse the average home. You are much more blast-resistant than your house, but that won’t help if it collapses on you. Most fatalities from blast will be indirect, and caused by collapsing buildings.
There are a few things you can do though. Heavy curtains will slow or stop flying glass, which can save you from injuries if a weapon explodes before you have a chance to get to your fallout room. If you can, cut down any trees that could fall on your home – because if they can fall on it, a nuclear blast pretty much guarantees that they will. Clear away loose items from outside. Trash cans or bikes, picked up by the blast and slammed into the front wall of your house, can make the difference between it making it through the explosion or collapsing on top of you. Lightweight wooden sheds or barns will go down at a much lower overpressure than your house so move anything vital out of them. If they’re really flimsy, knock them down yourself; that’s better than having them turned into flying missiles.
Once the overpressure of the blast wave moves on it’s followed by a sudden drop in pressure, then another reflected blast wave as air rushes back into the low-pressure area behind the shock front. This means stuff can be picked up and thrown at your home from all directions. The sudden pressure changes can be enough to make some buildings literally explode. Don’t leave doors or windows open to try and prevent this though; if the blast wave is powerful enough to explode your house it will break the windows anyway.
When a nuclear weapon explodes only a small amount of its mass – a few pounds – is converted into energy. The rest, which can be anywhere up to a ton, is superheated by the reaction and turned to incredibly hot, highly radioactive plasma. Tons of dust and debris – if the fireball created by the explosion touches the ground, thousands of tons – will be sucked up through the fireball and mixed with the plasma, which will cool and condense as the fireball dissipates.
All this dust – blasted by radiation, fused together with bomb material and reduced to the consistency of fine sand – is pumped up into the mushroom cloud and dispersed to become fallout. The heavier particles will start falling downwind of Ground Zero within minutes of the blast; the lighter ones, depending on how high they go, can be carried into the stratosphere’s high-altitude winds and come down almost anywhere in the world. In the two weeks following a nuclear attack the whole planet will get a very light dusting of fallout.
Don’t give up hope just yet, though. Fallout doesn’t stay dangerous forever. Its radioactivity falls according to the 7/10 rule – for every sevenfold increase in time since the blast, radiation levels drop to a tenth of what they were:
- An hour after the explosion the fallout might be creating a radiation level of 1,000 roentgens per hour (R/hr); five minutes’ exposure to this is often enough to cause radiation sickness. Half an hour will kill about half the people who’re exposed, and everyone who’s exposed to it for an hour will be dead inside a few days.
- After another seven hours the radiation level will have fallen to 100R/hr;
- 49 hours later it’s down to 10R/hr.
- Two weeks after the attack it will be 1R/hr, and at that point you can be exposed for several hours a day without serious risk of radiation sickness.
- A year after the attack radiation levels will be close to normal background levels.
The Fallout Room
Obviously, the key to survival is to avoid the fallout until its initial extreme radioactivity has decayed to a less dangerous level. To do this you need to prepare a fallout room in your home. Ideally this should be an inside room with no external walls. Firstly, it’s easier to keep fallout from getting into it. Secondly, any radiation from fallout outside that penetrates the walls will lose intensity with distance – remember that inverse square law – and will also be partly absorbed by walls and furniture. Choose a room as far from the roof as possible, because fallout will collect there – and, if it’s damaged, the lethal dust will get through. If you have a basement, use that; it will be almost completely protected against radiation from outside.
Many homes don’t have a room with no external walls, so you’ll have to improvise.Pick a room at the downwind side if you can, because less fallout will be blown up against the walls. Now seal the room as well as you can. Block up any windows, air vents or other openings as tightly as you can. Try not to just seal them with plastic sheet on the inside, because if any fallout gets through it’s going to be trapped between the plastic and the wall. That means any radiation from it will be in the room with you, and you really need to keep it outside.
Once the room is sealed you have to thicken the walls. The main hazard is going to be beta radiation, and that can make it through a few inches of wood or nearly an inch of aluminum. The more mass you can put between yourself and the fallout, the better. If you have the time and materials reinforce the outside of the external walls to a height of six feet above the floor. A layer of brick or cinder block is good. If you can’t do that, sandbags are good – use stakes and wire to hold them in place so they can resist blast, or stack them on the inside. Stacks of books will also absorb beta particles, and you can use heavy furniture too. Basically any dense, heavy material will absorb the radiation before it can reach into your fallout room.
There’s some stuff you should store in the fallout room, because you’re going to be staying in there for two weeks after the attack. The first thing is food, ideally stuff you can eat cold. Then stock as much water as possible, in sealed or at least covered containers – water in an uncovered bucket can collect any fallout that does get in. Firefighting equipment and camping gear should be in your fallout room, and any comforts you have space for.
You’ll also need either a chemical toilet, or a bucket and a supply of strong garbage bags to line it with. Put two garbage cans, with lids, right outside the door of the fallout room; use one for bags from the toilet bucket, and the other for the rest of your garbage.
There’s one more thing to do. Inside the fallout room, as far away from outside walls as possible, you need to build your inner refuge. This is a small, heavily shielded shelter for maximum protection from radiation. If you have a big, heavy table you can use that as a base. Pile up heavy furniture, sandbags, books and anything else dense around it, cover it so it’s as enclosed as possible and have some boxes full of books or dirt that can be pulled in front of the entrance.
If you don’t have a table dismount one or two doors – take them from upstairs if you can – and prop them at 45° against the wall. Secure them by nailing a strip of wood to the floor so they can’t slide, and cover them with books or sandbags. Again, have something to block the entrance.
After an attack get into your fallout room as soon as possible, and into the inner refuge. For at least 48 hours, only leave the inner refuge when it’s absolutely necessary. Radiation is at its highest during this time and most likely there will be a raised level inside the fallout room; stay as protected as you can.
After two days you can spend more time outside the refuge, but don’t leave the fallout room. When you need to get rid of toilet waste or garbage just open the door as far as necessary, drop the bag in the right trash can and shut the door right away. Close it smoothly though – don’t slam it. The last thing you want to do is stir up any dust, because some of it will be fallout. Stay in the fallout room for at least two weeks, and longer if you can; sleep in the inner refuge, and if you’re not doing anything go in there as well. The more protected you are the better.
Preparing your house seems like a lot of work, but you can do a pretty good job of it in two or three days. It’s worth the effort. If that two or three days makes the difference between your house catching fire or not, you’ll have a safe place to shelter from the fallout. Don’t prepare your home and there’s a good chance you’ll be out there, desperately looking for shelter, as the radioactive dust starts to fall. If that happens your chances of survival aren’t high – and when that’s your alternative, preparing your home to resist the attack doesn’t seem like that big a job.