Survival bunkers are coveted by many as the ultimate survival preparation possible, providing it is full of food and water. The common elements for any shelter are food, drinking water, air circulation and waste removal. Honourable mention goes to electrical power and heating and cooling. The extent and the capacity of these essentials depends on the purpose of the shelter or bunker and how long it will be occupied. The characteristic that almost can go without saying, storage, lots of storage.
Many of the features described in this article are possible to build into almost any structure, some will only be possible or necessary in a fortified bunker. One note on fortified structures, many municipalities have made fortified homes illegal. This was done where I live to combat organised crime, and make it possible to evict criminal organisations, easier to raid these structures and to discourage to setting up of a headquarters in the first place. Be aware of what is legal before you start to fortify any structure.
The first decision to make is if your shelter will be underground or above ground. Both options have advantages and disadvantages. Underground bunkers are easily hidden and offer excellent concealment. The ground around the walls also offers protection from most explosions and most forms of natural disasters. Underground is a great place to hide. Underground is not a great place to defend. Civil unrest can easily exploit a weakness in all underground structures, if all the exits are found by an aggressive party then all inhabitants of the bunker are trapped. All anyone has to do is wait with weapons pointed at the doors, because the doors will eventually open when supplies run out. They won’t even have to wait that long. Blocking air vents, adding toxic gasses and flooding the bunker with water will flush people out faster. The primary security of underground bunkers is secrecy. Keep the location and if possible the existence of any bunker secret. This may even be more important than the strength of the walls.
Whether you choose to build above ground or underground there are features that are vital for both.
Multiple exits, are needed. There is little use in getting trapped in your survival shelter just to die later. Always have another way out. Speaking of exits, installing a barrier that forms a ninety degree bend outside the door will inhibit people from knocking the door down. A cinder block or concrete construction with just enough room to open the door will prevent anyone from swinging a battering ram against the door.
Bunkers that expect to be occupied for extended periods of time should have a UV growth lighting system. Something to at least start some seedlings. Volcanic eruption can create shorter growing seasons. Giving your food plants a head start could make all the difference between harvest and starvation. It would be awesome to have an underground farm that can grow enough food for your entire family, but I would bet money that it is too impractical to be a viable option.
Air circulation is also critical. Simple air circulation can occur with two holes and a fan. Easy to install but the can and will leave you open to any airborne contaminants or contagions. Screens and U-bends will keep out rodents and water. HEPA filters remove many small particles and some airborne bacteria and viruses. You can also use UV light to disinfect the air before it is circulated. And it is best done right after the HEPA filter.
Everything else requires a positive pressure system to keep any contaminants outside. Positive pressure is achieved when air is blown into a room faster than it can be released. This means air will constantly push out of any leaking point and physically push away from the bunker. Even when doors are opened the air will push our preventing contaminants from entering.
This is the opposite of an isolation room, like the ones in a hospital. Isolation rooms remove air from a room faster than air can enter the room. This means air is pulled inside constantly and out to an air disinfection system. This keeps the airborne contagion contained in the one room even when doors are opened.
Both positive and negative pressure systems have higher electricity costs and that could limit their applications.
Water needs mentioning. A source of drinking water is essential as well. Length of stay is the master here. If you only have a storm shelter then you can probably get away with storage of water. If you plan on outlasting extended civil unrest, then a well with access inside the bunker is preferred. A method of disinfection of drinking water is also preferential.
Next is waste, all the garbage and sewage needs to be dealt with. A septic tank can receive the sewage easily enough if the terrain allows for it. Garbage can be incinerated from within the bunker. For more on solid waste and liquid waste management see my other articles.
Fortification is a useful way to help survive many situations. Whether you expect a tornado or World War Three, having a place to retreat to that can take a beating could save your life. Anything that could save your life one day is always worth a closer look.