May 052013
Whether intentional or accidental, a vehicle can very effectively smash through most unprotected building exteriors.

Whether intentional or accidental, a vehicle can very effectively smash through most unprotected building exteriors.

You probably already know that your retreat needs to be reasonably protected against high velocity ballistic attack, which is a fancy way of saying it should be more or less ‘bullet-proof’.  But have you thought about low velocity attacks?

What do we mean by low velocity attacks?  We mean instead of having small rapidly moving things (ie bullets) impacting on the side of your retreat and possibly penetrating through the walls, having much larger but slower moving things impacting on the side of your retreat and again possibly penetrating the walls.

The first example of such an object would be a traditional battering ram.  We’re going to hope that there’s not much chance of an enemy being able to deploy a battering ram against your retreat doors or windows, because that would presumably expose the people with the battering ram to sustained fire from you and your fellow defenders, to the point that by the time they’d positioned their ram and started to use it, they’d have experienced unacceptable casualties, causing them to break off the attack.

But there’s another type of low velocity ballistic weapon which you need to consider.  What say the bad guys simply drive a car or truck at full speed up to your retreat and crash it in through the walls?

To put things in perspective, a typical pistol bullet has in the order of 300 – 900 ft lbs of kinetic energy.  A .308 rifle round is in the order of 2000 – 2500 ft lbs.

A 5,000 lb car or truck, traveling at 30 mph, has 150,000 ft lbs of kinetic energy.  Get its speed up to 42 mph and it has 300,000 ft lbs of energy.  If you can get it to 60 mph, it will have 600,000 ft lbs of kinetic energy.

A passenger car, even at fairly low speeds, can crash right through the exterior of a typical stick built home, and end up in the living room (we know this from experience).  Add extra weight, reinforce the front with a ram to focus all that energy in one concentrated area, and get the speed up a bit, and any attacker has a formidable weapon.

It isn’t even a very high-tech weapon.  Any old vehicle, as long as it can be driven, will work perfectly well.

One more point.  With safety belts (and possibly air bags), even at quite high speeds, the person driving the vehicle into your house is unlikely to be harmed.  The reason for this is that the impact event is spread out over time and distance, so instead of a deadly sudden impact lasting only a few hundreds of a second, it is a survivable impact that extends over a second or longer.

There’s another issue, too.  At even a fairly slow 30 mph, the vehicle is covering 45 feet every second.  If you have, say, a 250 ft ‘clear zone’ around your retreat, that means it takes the vehicle just over five seconds from when it first appears to when it is crashing through your wall.  That’s not much time to respond to the threat – even if you were on active sentry duty, at least a second to recognize the threat and start a response, another second or more to get your rifle shouldered, sighted, and safety off, and that leaves less than three seconds to try to do something.

With the vehicle being a moving target and its angle to you probably rapidly changing (meaning you need to appreciably lead the target with your sighting – how much practice do you have at that?), your chance of getting any effective fire on it is minimal.  Even if you could get some rounds landing on the vehicle, and while that might injure or kill the people inside, you’re almost certainly not going to stop the vehicle continuing on and into your wall.

Sacrificing a vehicle to break into your retreat might seem like an extreme move that not many attacking groups would willingly do, but if that’s what you think, maybe you should think again.

Our prediction is that in a Level 2/3 situation, vehicles will be a dime a dozen.  What will be in precious short supply is fuel for the vehicles, but how much fuel does it take to start a vehicle, gun the engine, and drive it at full power a couple of hundred yards?  A pint or two of petrol should do the trick.

An adversary could have a team of horses tow the vehicle to close to your retreat and would only need to use precious petrol for the last short powered dash of the vehicle into your outer wall.

Such a method of attack – unless you had prepared for it – would be very hard to resist.  It behooves you to consider this risk and devise appropriate defensive measures.

The obvious solution might be to strengthen your walls still further, but that’s not necessarily the best, and certainly is far from the only possible response.  Generally, we’d recommend the better thing to do is to prevent potentially threatening vehicles from being able to approach your retreat at any speed other than a crawl.  Keep the battle at a safe distance from your retreat whenever possible.

There are two ways to do this.  The first involves ‘taking things away from the ground’ and the second involves ‘adding things to the ground’.  In other words, digging holes and ditches, or adding obstructions and obstacles.

Obstructions and Obstacles

An obstacle doesn’t need to be large to be effective.  It can be either permanently mounted (ie dug deep into the ground to hold it in place) or can be relatively mobile.  There are many different types of obstacles, but for simplicity, we’ll consider four primary types.

In sequence from easy and simple to largest and most complex, the first type is very simple – known as caltrops, these are nothing more than metal spikes/stars that you can sprinkle over the ground.  At least one of the spikes always sticks up and so will puncture a vehicle’s tire(s).

The best caltrops are made out of hollow tubing, so as to increase the certainty and speed of the tire puncturing.

The nice thing about caltrops is they are low tech, simple to make, and quick and easy to deploy and similarly not difficult to remove again.  You might be thinking ‘if I can easily remove them, so too could an attacker’, and that is half-true.  But while the attacker is out there, sweeping aside your caltrops, he is very exposed and vulnerable to your defensive fire, and he has lost the ability to surprise you with a vehicle coming from nowhere and cannoning into your retreat unexpectedly.

You could even have a caltrop deploying device – a slingshot or something – that would enable you to throw more caltrops onto any cleared pathway.  You’d be tossing them out from behind cover, while the bad guys would have to be exposed in the open to clear them.

A second type of low tech very simple obstacle is almost laughable in its simplicity, but people who have seen this in action assure us of its effectiveness.  Simply strew old car/truck tires where you wish to impede on-coming traffic.

We are told that this will massively slow down an oncoming vehicle, as it suddenly finds itself having to go up and down over tires that are probably each 6″ – 12″ high.  Like the caltrops, the tires can be spread out and cleared on an ‘as needed’ basis, and while an opposing force could also clear the tires, that would again involve exposing themselves to your defensive fire.

A really determined enemy could devise a ‘snow plow’ or ‘cow catcher’ front to put on their vehicle that would deflect tires and caltrops away, although it would probably have to do so at lower speed.

The bottom line for both these approaches (and indeed for all of them) is that a truly comprehensive defense involves using multiple layers and strategies, and you have to realistically decide where to draw the line and how much is enough.

The third type is what are sometimes called Czech hedgehogs.  They are structures that might be freestanding, or possibly weakly anchored.  They might be individual units or possibly may be linked together, and might be made out of metal or concrete.  They work best when they are only slightly taller than the clearance underneath the class of vehicles they are designed to stop – that is a reasonably known quantity when defending against tanks, but in your case, you might be confronting anything from a low slung sports car to a ridiculously raised 4×4.

So these are not so good as a general purpose ‘one size fits all’ device.

The fourth type are large heavy concrete blocks – possibly in pyramid shape, possibly just pillars or some other shape.  These objects are more commonly securely mounted in the ground.  They have been called dragon’s teeth (and many other names too).

Unless they are ridiculously solid, they are vulnerable to being knocked over by a sufficiently strong oncoming vehicle.  But in the course of being knocked over, they will absorb a great deal of the vehicle’s energy.  They are particularly good, in this ‘sacrificial mode’ when reasonably close to your retreat exterior, so in the event of them failing, the vehicle won’t have enough distance to build up speed again.

Noting that attacking vehicles might have been raised up on trick suspension, we’d suggest you need to make any sort of obstruction fairly tall, and we don’t really much like that concept too much because you may then be providing cover for enemy forces to shelter behind when attacking you.

Obviously, obstacles can also be large and prominent.  You could have a three-foot high and three-foot thick wall (perhaps a type of Hesco bastion, for example).  But then you run the risk of providing a defensive cover for your attackers to shelter behind, hence our focus on smaller sized obstacles that don’t have this type of downside associated with them.

There’s another type of simple but effective device for slowing down vehicles, but it is not without its limitations in our sort of environment :  A gravel pit, such as you sometimes see going down long steep hills for runaway trucks.  If you’ve ever seen one of those, you may have noticed how short it seems – those gravel pits do a great job of slowing down and stopping a speeding truck on a steep slope and would do the same for any vehicles approach you at speed too.

Arrester beds typically have a depth of between two and three feet of small-sized gravel in them.  Some locations use sand, which provides a much stronger decelerating force, but in cold winters, the sand will freeze into solid blocks and cease to function as a dragging medium, instead it becomes a smooth surface for the vehicle to drive over, unimpeded.  A loose gravel pit will probably still work as intended in freezing weather.

The shape of the gravel is important – ideally it should be fairly well-rounded, enabling each piece to move and slide over each other piece, rather than causing pieces to interlock together and present a firmer more solid platform for the vehicle to drive on the top of.

A truck at 45 mph typically takes 200 – 250 ft to stop in an arrester bed.  That becomes a massive waste of space if being used to defend a retreat on all sides, unfortunately, making arrester beds less practical for retreat defense.

In addition to gravel and sand arrester beds, there is a special type of collapsible concrete material used at some airports as a run-off zone at the end of runways.  This material stops planes safely and quickly and in less distance.  This ‘engineered material’ has also been used to protect the approaches to secure locations, being a discreet way of providing protection against vehicular attacks.  It is more expensive, but takes up less space.

Unlike gravel, which is a relatively low tech product that can be probably fairly easily replaced or just raked back into place, once the collapsing concrete blocks have stopped a vehicle they need to be replaced.  This would be difficult in a Level 2/3 situation, and you’re still looking at a requirement for at least 100 ft of arresting zone.

Ditches and Moats

A defensive ditch can be a great vehicle stopper.  It can also slow the advance of regular infantry forces, although note that any such ditch needs to be designed so it doesn’t inadvertently provide a secure position for enemy troops to regroup in and then press their attack against you.  In other words, the closer the ditch is to you, the more readily you’ll be able to shoot down into the ditch, and the less cover it will provide an attacking force.

If you have abundant supplies of water, adding water to a ditch makes it into a moat, which can slow down the progress of enemy forces and vehicles even more effectively.

A moat can be expensive to create, especially if you line it with concrete, although it would be possible to line a moat with puddled mud as an alternative.  Depending on where your retreat was located and the wind and weather conditions, you could expect appreciable evaporation in summer, and if it froze over the winter it would not be very effective while frozen solid.  A possibly easy solution to that would be to partially or completely drain the moat in fall and refill it in spring, assuming water is plentiful.

Moats and trenches can be bridged over, and if they are not very wide, maybe by nothing more sophisticated than 2″x12″ planking, although such an arrangement would not allow for a vehicle to proceed over at high-speed.

Traditionally, castle moats were at least 12 ft wide, and ranged in-depth from as little as 3 ft to as much as 30 ft.  Ideally they would be too deep to allow an attacker to wade across.  A 30 ft depth is of course not so essential, but one benefit of a deeper moat was (and still could be) that it protected the structure inside the moat from tunnelers.  Unlike medieval sieges, we feel it unlikely that any attacking force against your retreat would go to that degree of effort, whereas the depth of moat might interfere with your own escape tunnels out of your retreat.

Clearly the width is an important parameter – the wider, the better, at least up to a certain point.  But it is also necessary to consider cost.  For example, if we say your retreat exterior measures 40′ x 100′, and if we say there is a three-foot space between the building’s exterior walls and the start of the moat, and let’s make the moat 15 ft wide and 8 ft deep, that’s a lot of excavation (44,000 cu ft of dirt).  You could use some of that to build up the raised berm on which your retreat stands, and you’re sure to find a landscaping or strategic use for the rest, but you’ll still have to pay a considerable sum for the earthworks.

If you decide to line your moat with concrete, and if you have a six-inch thick floor and walls (some sources suggest thicker walls), then using the same moat dimensions as in the previous paragraph, you need 5624 cu ft of concrete, or 210 yards.  At a total cost for the concrete and pouring of perhaps $200/yard, that’s close on $45,000 for the concrete alone.

As for the water required, let’s say you decide to fill the 8′ deep moat with 6′ of water.  That would require 245,000 gallons of water.

One more interesting factor about a moat.  On a warm summer’s day with a gentle breeze, you would lose at least 1,000 gallons of water a day to evaporation.  Note that the evaporative loss rate is unaffected by the depth of water – it is proportional to the surface area of water, not its depth (and also to the temperature, humidity, and wind speed), so simply reducing the depth of moat water would do nothing to reduce the rate of evaporation.

Of course, a moat is effective whether wet or dry.  If dry, it is a ditch and still prevents vehicles transiting over it, and slows people down – they have to climb down 8 ft (in the example we have been using) and then climb up 8 ft at the other side, and then have only a very slim 3ft ‘work area’ pressed up hard against your retreat’s exterior walls.  The more water in the moat, the slower their progress across it will be, and the more difficult it will be to take equipment with them.

If you find yourself choosing between a deeper moat and a wider moat, then assuming you have a minimum width of 12′ or slightly greater, you would be best advised to make your moat deeper rather than wider.  There is little or no added value in increasing the width – the difficulty of a moat is mainly in the ‘transitions’ from level ground to whatever depth/differential the moat is, and then from whatever level the moat is to the ground on the other side.

Ideally, we’d recommend the water depth be 6′ or slightly greater so that people can’t conveniently walk across, and then any extra depth should be used to create a vertical air space/wall between the water level and the ground level.  Getting in and out of a moat is even more difficult if you have to ascend or descend more than a convenient number of feet, and with water rather than solid ground at the lower level.

Allowing for Legitimate Vehicle Passage

You need your own vehicles to be able to travel through your obstructions, and you’ll also have legitimate friendly traffic coming and going too.

If you have a ditch or moat, obviously the solution for that is to provide a drawbridge – either a device like in old-fashioned castles that raises up and lowers down, or alternatively one which extends out from your retreat to the other side, or one which rotates/swivels.  Of course, whichever design you use needs to be very secure so that an opposing force can’t take over its mechanism and lower/extend/rotate it to span the moat against your will.

If you are relying on a series of above ground obstacles, you need a lane through them that vehicles can travel, and by including tight turns, you ensure that the vehicles have to move slowly.

The best type of tight turn is to require a three-point (or sometimes called ‘Y’) turn.  Because it requires the vehicle to actually stop, reverse, then proceed on forwards again, this is a very effective delay.

Of course, having had to very slowly work through the obstacles would cause the enemy to be in the open and exposed to your defensive fire for an extended period, plus means that when they finally do arrive close to your retreat wall, they are moving slowly rather than quickly.

Note that when you are planning for how you will allow legitimate traffic to come and go, you need to consider the dimensions and turning abilities of the largest probable type of vehicle that may legitimately visit.  This could be as large as a semi truck/trailer unit with a 56′ long container behind the tractor unit; alternatively, you might decide to have a staging point somewhere remote from your retreat where larger vehicles can be unloaded to smaller vehicles.

That is a much less efficient arrangement, so if it is possible to allow for at least moderately large semi trucks to get through your ‘maze’ that would be the best option.

A Last Line of Physical Defense

Naturally you want to stop vehicle attacks some safe distance from your retreat.  Even a slow speed vehicle, when approaching your retreat, can provide cover for enemy attackers sheltering behind or alongside the vehicle as it slowly moves forward, so some type of obstacle arrangement is essential.

Unavoidably, the further away from your retreat you place such defenses, the more extensive they will have to be.  If you have a retreat with perhaps 40′ x 100′ exterior walls, the walls themselves have a length of 280 ft.  If your vehicle barriers are a mere 100 ft away from your retreat (a distance that a sprinting attacker could cover in four seconds or less) then they will be a massive 1080 linear feet in size.

So possibly you’ll have a partial line of obstructions at a distance to slow down incoming vehicles, then a more severe obstacle design closer in to stop them.  This is the concept of layered defenses – it also helps you to understand the intentions of people approaching your retreat, requiring them to show aggression earlier on.

In addition, if the budget allows for it, maybe it makes sense to have a last line of defense that is actually immediately adjacent to – or even part of – your retreat wall.

One form of this would be an immediately adjoining moat.  Another form would be to build your entire retreat above grade on a berm.  Maybe the first three feet or so of the retreat is nothing other than a solid earth foundation.  In addition to its three-foot (or more) height, f you had this solid earth foundation extend out even only another foot or so (due to it being liable to be compressed if hit by a vehicle) that would be a very strong stand-off layer.

Having your retreat an extra three feet higher is a good thing for all reasons, giving you a better commanding view of your surroundings.  And presumably at least part of that extra three feet of height would be used to get you a head start on excavating basements, too – your below grade basements would in effect have their first three feet above ground level, but still be treated as basement.

In the event that you were blessed with a water table that was very close to the surface, raising up the ground level of your retreat structure is obviously very beneficial.

Whether you raise up your retreat or not, you definitely should make sure there’s not a downhill slope running towards your retreat.  That just makes it so much easier for an incoming vehicle to gather more speed and more energy.  It isn’t only bad feng shui to have your house lower than the surrounding area, it is bad strategy too.


There will be three major categories of physical threat against your retreat.  Bullets, heavy weights and vehicles, and people.  A good series of obstructive defenses will help keep vehicles away from your retreat walls, and will slow down the speed at which people can reach your walls too.

It is easy to underestimate how far away a person can be and still be an immediate danger.  A person 100 yards away can cover that distance, if there are no obstructions, in about 10 seconds, whereas if you’re just going about your ordinary lives in your retreat, there’s no way you can mount an effective defense with that little warning.

Rather than creating impractically huge clear zones around your retreat, you need to slow down the speed at which people as well as vehicles can get to your retreat, to buy you time to prepare an effective defense.

Above ground obstructions have some value in slowing down vehicles, but are less effective against individuals on foot.  Fencing works well against people (but probably not vehicles).  Ditches and moats will stop most vehicles and slow down people.

Apr 282013
We recommend you should build up not out when designing your retreat dwelling.

We recommend you should build up not out when designing your retreat dwelling.

When it comes to choosing a retreat, you will find that there are no suitably constructed dwellings already built and in place.

If you want to have a long-lasting retreat structure (and of course you do!) you’ll have to design it to very different criteria than how a typical spec-builder does.  He of course wishes to create the ‘most’ structure for the lowest cost, and only needs it to remain fully functional until its new-home warranty expires.

We discuss the limitations of normal home design and construction techniques in this linked article specifically, and in the retreat design topic in general.

Let’s consider the implications of one major choice you need to make.  Should your retreat be a sprawling rambler type dwelling or should it have a smaller ground footprint and be two or more stories high?

We recommend you build a multi-level dwelling, and would suggest three levels to be a good compromise to adopt.  Here is a review of the various issues that are associated with choosing how many levels to design into your retreat structure.

Note that the local zoning and building codes may have restrictions on how high your dwelling structure can be.

1.  Less External Wall Perimeter

Your external walls are your most important walls and most expensive to construct.

Any attacks will almost invariably be directed against your external walls.  The only other notable point of attack would be to your roof, and with a multi-level structure, not only will your exterior walls be shorter, but your roof area will be less too.

Keeping your perimeter as short as possible allows you to concentrate your defenses along a shorter perimeter line, and simultaneously slightly funnels your attackers into a narrower line of attack.

Going from one level to two levels will reduce your building perimeter by 30% – 40%.  But (and perhaps counter-intuitively), it will also increase the total area in square feet of exterior wall by anything from 10% – 35%.

Going from one to three levels will reduce your building perimeter by 40% – 45%, but will increase the total square feet of exterior wall by anything from 25% – 60%.

As you can see, as you add extra levels (while keeping total internal square footage the same) the reduction in perimeter becomes successively less, while the increase in total wall square footage becomes successively more.  If this were the only consideration, you’d probably want to keep your retreat one or two levels.  However, there are other issues to consider which we feel argue convincingly in favor of going to three levels.

2. No Need for Heavier Construction Materials

One downside to multi-level construction of typical dwellings is that you need to build your supporting structures to a higher loading capacity to support multiple levels of dwelling.  That becomes an appreciable offsetting extra cost.

But you’re building your retreat dwelling ‘over-spec’ anyway.  You already have stronger than necessary external walls and load bearing supports, so all that this means is that the extra strength you have designed into the structure is now being put to some actual purpose.

Remember when people start to talk to you about the extra costs of constructing multi-level structures that these extra costs are not extra in your case; they only apply in the case of people seeking to build the least robust structure they can get approved by local building codes.

3.  Roof Impacts

Going from one to two levels will reduce your roof area by half.  Going to three levels reduces the roof area to one-third of its original size.

The reduced amount of roof probably goes a long way to compensating for the cost of extra exterior walls.

But there might be two situations where less roof is not a good thing.  The first might be to do with water collection.  If you are in an arid area with little rainfall and few convenient other sources of water, you’ll surely be using every square foot of roof area for rainwater collection, and reducing your rainwater collection area by 50% (or 67% for three-level construction) might be an undesirable outcome.

The other circumstance relates to solar energy sourcing (either through photo-voltaic solar cells for electricity or through solar heating installations).  You certainly should have those parts of your roof with appropriate southerly facing aspects close to completely lined with either solar cells or solar heating devices.  Even if you have abundant other energy sources, prudence dictates that you want to have multiple sources, each sufficient in and of itself, so if something happens to one source, you still have at least one other energy source to fall back on while the other source is (hopefully) being returned to service.

Energy, more than anything else, is life in a post-TEOTWAWKI situation.

If the loss of roof area for solar energy collectors is a problem, there’s no reason why you can’t create another structure that is primarily a support/protective structure on which to mount additional solar energy collectors.  The same structure could of course do double duty as a water collector too, and could be constructed very inexpensively.

4.  Energy Losses

Continuing on the energy theme, not only is energy your most vital resource in a Level 3 situation (and lesserly so in Levels 1 and 2) it will become very expensive and precious.  Anything to reduce your energy needs becomes of paramount importance, and this is a factor that needs to figure into your building design much more than at the present where energy is abundant, affordable, and assured.

A building loses energy (ie heating/cooling) through its exterior – its outside walls, its roof, and also its flooring.  A rambler has more external surface (ie wall area plus roof area) than a two level building, and about the same as a three level building.

Adding in an allowance for floor heat losses too and it is clear that both two and three level structures are more energy-efficient than single level structures, although when you move on to a fourth level, the energy saving becomes neutral, tending negative.

This is another reason why three level structures are an ideal compromise.

5.  Functional Convenience

We’ve lived in ramblers, two-level, and three level dwellings – perhaps you have, too.  We love the convenience of no stairs in a rambler, but in reality, in a well designed multi-level structure, there are not a huge number of occasions during the day when you need to go all the way up or down from the top to the bottom level.

We would suggest a general design strategy that has storage on the lowest level, living areas on the middle level, and bedrooms on the top level.  That means that during the day, you are mainly in the middle level, occasionally going down to the lowest level and to the outside, and rarely going up to the top level, and almost never needing to go all the way from top to bottom and back again (or vice versa).

This strategy would also allow you to have the lowest amount of heating/cooling on the bottom level, cutting down the effective heating/cooling volume of your structure.

Some countries have traditional multi-level buildings in which livestock are kept in the lowest (ground) level.  This is a great idea too, but if you choose to do this, be aware that animals and their excrement can be smelly.  You’d have to think carefully about the implications of this!

6. Defensive Issues

There are several benefits offered by a multi-level building compared to a single level building.

As mentioned in passing above, a multi-level building has a shorter perimeter to defend, and by implication, people inside the structure can more quickly travel from one place to another – if you are being attacked on several fronts,  it can be easier to shift people from one side to another and to generally keep in contact with each other.

A multi-level structure with primarily storage on the bottom level can forego most of the windows on that level that would otherwise commonly be found, making it much more secure against physical intrusion.  If you have windows on the upper half of the second level, then the distance from the ground to the bottom of a window will be in the order of about 14 ft, making it difficult for intruders to quickly scale up and gain access through a window.

So by having living spaces on the second and third levels, you have the security of no windows at ground level while still having the lifestyle benefits of windows in the living areas.

A person on the third level will be close on twenty feet higher up than he would be on the first level, giving him a better view down to the surrounding ground around the retreat structure and making it harder for attackers to find cover.  Even better still would be a rampart or parapet at the roof level, giving still more height advantage.

7.  Communications

If you have a taller retreat, it is easier for you to maintain visual contact with people in your group who might be working on the land surrounding the retreat.  You can see them and they can see you, making for better security, and if necessary, some type of sound alarm (bell, whistle, siren, whatever) could be sounded at the retreat to call people back.

Lower level trees, bushes, shrubs and other things that would block your view if you were at ground level become less obstructive if you are another 20 ft up from the ground.

Being higher up can also greatly improve your radio communications.  If you have a three level structure, then your roof will be almost 20 ft higher than a one level structure.  This will extend your radio line of sight coverage (and also visual horizon) from about 4 miles to 7 miles.

Yes, of course you can mount an antenna on a mast above your rambler to get extra height, but you can do the same thing from a tri-level dwelling too.  No matter what you do, you have an extra almost 20 ft of height advantage.

8.  Land Saving

If we are considering the difference between a 3000 sq ft rambler, or a two-level equivalent structure (with a 1500 sq ft footprint) or a three-level equivalent structure (with a 1000 sq ft footprint) it might seem that the saving of either 1500 sq ft or 2000 sq ft of land is negligible, particularly if your total lot size is maybe 500,000 sq ft (ie about 11.5 acres).  You’re looking at a saving of less than 0.5%.

But the saving is actually more substantial than this simplistic calculation would appear.  Your residence will have a low productivity zone around it – an area which is kept reasonably undeveloped for security and convenience/access/maintenance reasons.  Maybe that zone extends out 25 ft, and if that is the case, the smaller footprint is magnified into a smaller overall surrounding zone, and you’re maybe saving not just 1500 sq ft of land, but 4500 – 6000 sq ft of land.  That’s becoming appreciable (0.1 or more acres).

Another Perspective – Multi-Family Dwellings or Multiple Retreat Buildings

All the preceding analysis has been based on the assumption of a single retreat structure, with the same number of square feet, but split over one, two, three or more levels.  In such a case, there is some benefit in going to two levels, less benefit in going to three, and probably no benefit in going to a fourth or more level.

But let’s consider not just your retreat structure, but also other buildings and structures at your retreat, and/or a second retreat structure for a second family.

If the choice is between two or three separate free-standing buildings, or one two or three level structure with the three separate structures in effect stacked on top of each other, the math changes completely.  Instead of getting reducing benefits, you now get increasing benefits.  There is no offsetting increase into total external wall square footage, but there are instead increasing savings in total roof area, total perimeter, total land footprint and energy efficiency each time you stack another formerly separate building on top of the others you have already combined.

When does the benefit of building up rather than building out cease to apply?  There comes a point when climbing stairs just becomes too much of a hassle.  Conceivably you could grow to four levels, by concentrating your living on levels two and three and using levels one and four for supplies and other infrequently needed/accessed items.

If you went to five levels, with levels two, three and four for main living, you could attempt to have younger and fitter people in level four, but clearly you are now starting to compromise general livability issues.  We know people who live on the fifth floor of apartment buildings, in apartment blocks with no elevators, and it isn’t much fun going up and down the stairs – not just alone, but having to schlep all one’s food (and often, all one’s water, too) up the stairs.

So we continue to feel that three or at the most four levels is the best compromise point.

If your consolidated building represents a number of otherwise freestanding dwellings, that is the best scenario.  But if you’re simply consolidating barns and sheds, that is not quite as cost-effective, because you are switching from a presumably low-cost construction method for a barn or shed to a ballistically resilient construction method as part of your main structure.  So there are less likely to be appreciable cost savings, but there are still other advantages.

Security Benefits of Building Consolidation

Consolidating multiple buildings into one tall building also offers an improvement in security for three reasons.  The first is that the easiest structure to defend is the one you are already in.  You don’t need to be patrolling other buildings.

The second reason is that if your property has, for example, a main retreat dwelling, together with a nearby barn, workshop and vehicle garage, then attackers could use these other buildings as cover and concealment; they could shelter behind them when attacking you in your retreat.

But if you have just one structure, you have no obstructions preventing you from having a clear field of fire (especially from your upper levels) to anywhere around you.

The third advantage is if you have consolidated two or more households into one structure.  You have a larger stronger group of people, all equally invested in protecting the one structure.  We touch on this in our article ‘Designing and Building a Retreat – The Bigger, the Better‘.

There’s another part of having a larger group of people in the one structure.  In our article ‘Community Mutual Defense Pacts‘ we point out that while it is all great in theory to have an agreement with your neighbors, a mile or two away, to support each other in the case of attack, the reality is that your neighbors are probably too far away to come to your aid quickly enough if needed, and the even uglier reality is that if you’re under attack, there’s a better than 50/50 chance that rather than risk their lives by coming to your aid, they’ll instead simply hunker down in their own retreat.

Clearly, if the other family is living in the same structure, neither of these constraints apply.

There a downside to putting all your structures into the one building, and that is the concept of putting all your eggs in one basket.  If something were to happen to your main structure, then you would have lost everything, whereas if you had two or three structures, you could lose any one of them and still have one or more remaining structures – that would not be a good thing, but it wouldn’t be a total disaster, either.


There are compelling reasons to switch from a rambler to a two level design of retreat building.  Going from two to three levels is not quite so clear-cut a decision, but probably makes sense for many preppers.

It also makes sense to build up rather than out when it comes to consolidating additional structures on your property.  It is generally more convenient and secure to integrate them all in the one multi-level building.

Apr 282013
A computer reconstruction of the 19th century Fort Laramie, WY.  Do the 'wild west' forts validate or invalidate the concept of defending your retreat?

A computer reconstruction of the 19th century Fort Laramie, WY. Do the ‘wild west’ forts validate or invalidate the concept of defending your retreat?

An awkward issue that preppers have to confront when planning for a possible problematic future is what to expect from other people.

Will people peacefully unite and work together effectively to create win-win examples of mutual survival?  Or will some group of society (maybe only a small minority) take advantage of a possible collapse of law-enforcement and in an anarchistic manner run amok in an orgy of looting, pillaging and plundering?

Opinions differ greatly as to what might occur.  But the simple fact that there are credible concerns about a general decay into lawlessness is enough to require prudent preppers to plan for this.  Whichever outcome might happen, a prudent prepper must necessarily consider not only the best case scenarios but also the worst case scenarios, and for sure, roving gangs of violent people who simply take anything they want by force is an unpleasant situation and some type of preparation for this must be considered and provided for.

A central part of the planning and preparing process revolves around one very big question :  Is it practical to make your retreat fully secure against determined attackers?  Is it even possible to do so?  When (or if) you find yourself confronted by an armed gang of looters, what should you do?  Shelter in your retreat?  Run away, leaving everything behind?  Fight to protect yourselves and your possessions?

There are many different opinions on how to respond to such an event, and you should form your own decision after having carefully considered all perspectives, all opinions, and – most of all – all facts.

It is certainly true that it is difficult to build a totally safe and secure retreat, especially while trying to keep the cost of construction to an affordable level.  Modern munitions have enormous power and can destroy very heavily fortified structures.  Besides which, if the first explosive device fails to blow a hole in your outside wall, an attacker may simply repeat a second and third time, progressively weakening your external fortifications until they eventually fail.

So, if any structure can potentially be defeated by a well armed and determined attacker, is there any point in spending potentially hundreds of thousands of dollars to strengthen it, in a case where such strength will always sooner or later be insufficient?  This is clearly a very important question and concept, and one which demands consideration.

A letter was posted on the Survivalblog website recently that raised some of these often discussed issues.  It is short, so to save you clicking to the link, this is what it said

A comment on the dual ring village concept. If it is advanced as a defense tactic, I would urge remembering that the walled-town versus siegecraft dynamic is thousands of years old, and the survival of walled towns and cities is only possible if they are:

  1. Provisioned to last longer than the besieging force, which is of course free to forage and be resupplied
  2. Fireproof
  3. Relieved by a friendly force from outside.

They are also utterly obsolete since the development of artillery bombardment, still more so since the airplane and missile. Sad but true.

IMHO, safety today must rely on:

  1. Invisibility or insignificance to possible enemy
  2. Effective surveillance of a wide perimeter
  3. Mobile defense force to engage potential enemy at a distance

War is not only Hell, but quite expensive!

We don’t disagree with the writer’s first three points, although in truth there is a great deal more than just three factors that apply to considering the dynamics of siege situations and their likely outcomes.  While the walled-town vs siege dynamic is thousands of years old, it is only in the last 500 – 1000 years that the relative safety of the walled-town has diminished compared to the ability of attackers to broach the fortifications.  Furthermore, it is less than 200 years ago when fortified positions were still being used to good effect, here in the US, to protect against Indians and outlaws – a reasonable analog of the situation that might be expected WTSHTF.

Indeed, the decline of forts in the US came not due to their failure to protect the people within them, but due to the peace and stability and stronger law enforcement that made such forts no longer essential.

If we were to look at history for lessons – and this is always a valid thing to do – we’d suggest that history has actually validated rather than invalidated the concept of fortified dwellings.

But let’s put the writer’s introductory comments to one side, because that’s not the main problem we have.  Keep reading on past his first three points and the conclusion he draws from them.

Now comes the trap.  We’re sure this writer didn’t deliberately adopt this well-known technique of demagoguery, but see what is happening here, and be aware when it is used to try to persuade you of other things in other situations.

The process is simple.  First you get the person you are trying to persuade to agree with you on some points which may range from ‘obviously’ true to probably true.  In the process you establish yourself as a credible expert in the person’s mind and get them in the habit of agreeing with you.  Salesmen are taught the same thing – you ask the prospect a series of questions to which the answer is ‘Yes’ then you ask him the big question – ‘Will you buy my used car’ and before the prospect has thought fully about it, he has reflexively answered yes again.

So, after the series of obviously true statements and agreements, second, comes the ‘sucker punch’.  You use the agreements on the initial points as a launching platform to adduce the apparently incontrovertible validity of some other points which superficially seem to be related to the points you’ve agreed upon, but which in truth may be completely unrelated and not directly linked.

Now, as we said, we’re sure the writer of this letter was well-meaning rather than trying to trick us, but – in our opinion – the net result is that he offers up three uncontroversial facts about a complex topic, and then slides from that to three opinions which are far from universally accepted.

Let’s focus in on his three claims.

1.  Safety relies on being invisible or insignificant to a possible enemy

Well, for sure, if you are invisible, your problems are reduced.  But – ummm, which aisle of the local store sells invisibility cloaks?  If you don’t have an invisibility cloak – and also the ‘absorbs all smells’ cloak and the ‘blocks all noise’ cloak, and if they are not large enough to cover your entire retreat, cultivated lands, wells, driveways, fencing, etc, then you’re not going to be invisible.

So saying that safety relies on being invisible is impractical and unrealistic.  You may as well say ‘safety relies on being invulnerable’ – and that’s about as likely as becoming invisible.

We do agree that it is prudent to observe ‘opsec’ and to minimize one’s profile to the world around one.  But we believe it is wildly improbable that you’ll remain undetected, longer term, and when you are detected, you need to have plans in place for how to now resolve problems.

The other half of the writer’s first point is to be insignificant.  But is this what you want, and is it possible, and even if it were, does it guarantee you a successful outcome when being confronted by a group of bad guys?  We think not.

Firstly, insignificant opponents are easy opponents.  Who would a theoretical enemy rather engage – a strong substantial well prepared force, or an insignificant small group of unarmed survivors?

Secondly, who wants to prep to be ‘insignificant’ in a future without rule of law?  Doesn’t the very fact that we have prepared and have supplies of food, shelter, energy, and everything else automatically shift us from the ‘insignificant’ to the ‘tempting’ category?  Is he saying ‘become starving and homeless and you’ll be okay’?

We should also think about the opposite to what he is saying – when he says that insignificant groups of people are safe, is he suggesting that marauders are drawn to making kamikaze type attacks on much stronger groups of well prepared communities?  That sure sounds counter-intuitive!

We’d suggest that in a future adverse situation, roving marauders will be opportunists, and will go after the ‘low hanging fruit’ – they’ll pick fights with people they know they can dominate, while leaving stronger adversaries well alone.

There’s one more thing as well.  This being insignificant thing – were you ever bullied at school (or, perhaps, were you a bully)?  Whichever you were, who were the people bullies would most pick on?  The highly visible popular students, or the less visible loners?  The lettered sports team jocks, or the puny weaklings?

How well did being insignificant work against bullies at school?  So tell me how being insignificant would work against bullies in a future dystopian world where bullies are running amok, free of any negative consequences?

There is never safety in weakness.  Only in strength.  So, this first claim seems to be in part impractical/impossible, and in other part, completely the opposite of what is more likely to occur.

2.  Safety relies on effective surveillance of a wide perimeter

There are a lot of assumptions wrapped up into this statement.  First of all, it seems to contradict his first point – an insignificant group lacks the resources to keep effective watch on a wide perimeter.  We’re not sure how wide a perimeter he is thinking of, but let’s say he is suggesting a one-quarter mile radius from your central retreat dwelling.  That makes for an 8300 foot perimeter – more than a mile and a half of perimeter.

For another measure, let’s say you have a ten-acre roughly square-shaped block of land, and you establish your perimeter on the boundary of your ten-acre block.  That perimeter would be probably about 3000 ft (a mile is 5280 ft), but that’s not a ‘wide’ perimeter.  It means you will see your opponents more or less at the same time they see the first signs of your property and the give-away indicators of fencing, cultivation, crops, animals, or whatever else.

It may not be practical to have a forward perimeter beyond your property – if you have neighbors, do they want you running patrols and maintaining forward observation posts on their land?  But if it is possible, and you have a perimeter another 150 ft out from your boundary, then you now have a 4,000 ft perimeter to patrol.

How many people will be required to patrol somewhere between 3000 and 8300 ft of perimeter?  That depends of course on the terrain and what type of vegetation you have.  Best case scenario might be eight people (say one in each corner of the 3000 ft ‘box’ and one in the middle of each side); worst case scenario could be 28 people (one every 100 yards with an 8300 ft perimeter).  You might be able to get away with fewer people during the day, and you’d probably need more people at night.

Now, even with ‘only’ eight people on duty, and let’s say that each person works eight hours a day, seven days a week, that still means you need a total team of 24 sentries to guard your perimeter, plus some additional staff for supervisors, central headquarter coordinating, and so on.  And that’s your best case scenario.  With the larger perimeter, you could end up needing 100 people for your total sentry/observation team.

So with somewhere between 25 and 100 able-bodied members of your community who are full-time tasked with doing nothing other than effectively surveilling a wide perimeter, one has to ask – how practical is that?

But let’s wave our magic wand over this part of his statement (you know, the one we used for our invisibility cloak too) and now ponder the next thought – what happens when an enemy force is detected approaching our invisible and insignificant community?  The writer answers that question in his third and last point.

3.  A Mobile Defense Force is Required to Engage Potential Enemies at a Distance

This is another very complicated concept that is not adequately conveyed in a short statement.  While it may be good military doctrine in the normal world to engage in such actions, in a Level 3 situation in particular, very different rules apply.  In a normal (or historical) military conflict, both forces are willing to accept casualties as part of furthering their cause, because they are assured of a vast to the point of almost limitless resupply of soldiers and munitions from ‘back home’ and because the commanders who make such decisions are not the fathers, brothers, and close personal friends of the soldiers they are willingly sacrificing.

But in a Level 3 situation, you only have the people with you in your community, and no replacements.  Plus, they are not strangers.  They are your friends and family.  What father will happily send his son out on a risky mission that might simultaneously see him lose his son and also see his community lose one of their precious able-bodied members?  Keep in mind also, with a collapse in health care resources, even small battlefield wounds will become life threatening.

There’s a terrible imbalance in this, too.  Although your community will have a small and irreplaceable resource of manpower – and a similarly small and irreplaceable resource of weaponry and munitions – it will be confronting a seemingly limitless number of roving gangs of aggressors.  Sure, you might successfully fight one gang off this week, but what about next week, the week after, and so on?

As we point out in our article about gangs being your biggest security threat, there were 1.4 million gang members in the US in 2010.  Now, of course, not all 1.4 million of those people are going to singlemindedly attack you, if for no other reason than geographical distances and the sure fact that many of them will lose their lives doing other things, elsewhere.  But how many more gang members will they recruit, and how many new gangs of all types will spring up when the rule of law evaporates?

So our first point is that in a future Level 3 situation, you are going to want to do all you can to protect your people and to avoid risking their lives and wellbeing.  You’ll not want to gratuitously start any firefights that you couldn’t otherwise avoid.

There’s more to critique in the writer’s third suggestion/statement, too.  If you are going to engage potential enemies, as he recommends, you need to surprise and ambush them.  So you’re going to have to have prepared ambush locations and defensive positions all around your retreat and wherever else you might choose to initiate contacts.

This strategy also links in to his earlier comment about a wide perimeter.  If your sentry perimeter is your property line or just beyond, or only one-quarter mile from your retreat, it will be impossible to ‘engage at a distance’ when you might not detect enemies until they are almost upon you.

Remember also you need to allow time from when your sentries have sounded an alarm to when your reaction force can group together and travel to the point of encounter.  This is indeed another reason for wanting to set your perimeter out as far as you can.

But if you extend your perimeter out to, say, 1 mile, you’ll have all sorts of issues with patrolling on other people’s land, and your manpower requirements will increase enormously.  You could quickly end up needing 500 people for sentry duty, and much more sophisticated communications systems to control and coordinate them all.  So that’s not going to work very well either, is it.

There’s also the simultaneous moral and tactical issue about what do you do when encountering – to use the writer’s term – a potential enemy?  If you do as he advocates and engage them at a distance, does that mean you’re opening fire on people who may have been quite peaceful and having no intention of attacking you?  Does that mean you’re killing people who didn’t even know you were there (remember, you’re also supposed to be insignificant and invisible)?

Or, if you’re giving them warnings, haven’t you just revealed your presence, and ceased to be both insignificant and invisible?  And, having given them a warning, you’ve now lost the initiative – they can decide, after making a show of retreating away, whether they’ll stay away, or if they’ll circle around and attack you unawares from another side.  (Oh, right, yes – your effective surveillance of a wide perimeter is keeping you safe.  Maybe.)

We could go on – for example, we could wonder how mobile the mobile force the writer advocates would actually be in a Level 3 situation.

Are we talking horses, or vehicles – if the latter, just how much gas do you have to burn on roving mobile patrols, and how complete an inventory of spares for the vehicles you’re using all day every day?  What type of roading will be required?  And how invisible/insignificant are you being with motorized patrols?

Alternatively, if you’re going to use horses, they aren’t a free source of mobility.  Horses require feeding, stabling, training, medical care, and so on.  You’ve just added yet another layer of complexity and cost and overhead to your retreat community.  Not only do you now have some hundreds of people full-time on sentry duty, but you now need a mobile force of, shall we say, 50 cavalrymen, and they in turn require how many extra people to care for their 50+ horses?

Remember the concept of a ‘horse acre’ – each horse requires almost an acre of farmland to be supported.  So the first 50 acres of your retreat are required for the cavalry horses, and the first 500 adults in your retreat are all either sentries or soldiers, and if we say you need another 1000 people to do productive work to cover their own needs plus those of the 500 strong security group, and if we say that these 1500 adults have on average at least one other family member, your retreat community has now grown to 3000 people.

Is that still small and insignificant?

Actually, we are probably being conservative about the proportion of ‘support people’ and civilians that are required to underpin your security force.  It is rare to find a country with more than 5% of their population in the armed services.  Even in the gravest parts of Britain’s struggle in both World Wars One and Two, with the entire country locked in a life and death struggle and every part of the economy devoted to supporting it troops, and with the civilian population suffering rationing of everything – food, clothing, energy, you name it – the largest force that Britain could field was only about 10% of their entire population, and that was for only a brief part of the war.

With possibly less automation in your post-WTSHTF community, and with the need to have a sustainable allocation of resources to defense compared to simple food production and survival, it is unlikely you could have much more than 5% of your total retreat population tasked with defense duties, and/or no more than 10% of your adult militarily fit (generally considered to be 17 – 49) population.

So there’s a rule of thumb – multiply your defense team numbers by 10 to get the total number of 17 – 49 year olds in your group, and by 20 to get a minimum total group size of all ages.  Or, working backwards, divide the count of adult able people in your group by ten and that’s about how many you can afford to spare for defense duties.

Some Alternative Thoughts

Okay, so the three ideas proposed by the letter writer don’t really make much sense, do they.  But we do probably all agree that being besieged by an opposing force is not a good situation, either.

So what is the solution?

This brings us to another trick of demagoguery.  Are the initial three statements, the statements we agreed with, actually applicable to our situation?  As we hinted at before, we suggest not.  We’re not talking about medieval wars between states, when brightly colored knights on horses jousted in a chivalrous manner with each other, and armies mounted sieges against lovely crenelated castles surrounded by moats, located obligingly on open fields.

We are talking about a roving group of marauders, probably numbering from a low of perhaps 10 up to a high of probably less than 50.  For sure, if they encounter us, they would be keen to take whatever they wished from us, but if they can’t do that, will they devote the next many months or years of their lives to mounting a siege?  Or will they give up and move on, because for sure, some miles further on will be some other small community who perhaps truly is insignificant and easier to plunder?

If fortified settlements worked well in the wild west against similar types of bandit groups, wouldn’t they work well again in a future Level 3 situation?

Our point is this – a strong well fortified central retreat is more likely to discourage rather than to encourage attackers to press on with an attack.  Sure, they might start off by attempting to overwhelm your group, but if they fail at the easy stuff, are they then going to risk losing more of their people and sweating the hard stuff?  We suggest not.

While it is true that modern artillery and air delivered munitions are beyond what we could realistically build defenses against, how likely is it that a roving group of marauders will be towing field artillery pieces, or have an airforce at their command?  Even if they did have some military grade munitions, do you think they would have many of such things, or maybe just one or two that they were reluctant to squander?

So what level of protection do you need to build into your retreat?

Realistic Construction Standards for Your Retreat

We suggest you design a retreat that can withstand being shot at by heavier caliber rifles, and which is fireproof.

It is certainly conceivable that attackers would have rifles, and it is certainly conceivable that their rifles would be in full size calibers such as 7.62×51 (ie .308) rather than in lighter calibers such as 5.56 (ie .223) or 762.×39 (ie Soviet type AK-47 calibre).

So your retreat should be built to be able to withstand multiple hits in a single location from .308 and similar calibers, and be constructed of a material that you can readily repair at the end of any such attack.

It also has to be strong enough to resist physical assault – in other words, if attackers get to your retreat’s exterior walls, you don’t want them to be able to break windows and climb in, or to knock down doors with a battering ram.  You want to physically block them by your exterior wall while you pour defensive fire down on them from protected positions on the top of the wall.

Talking about fire, it is certainly conceivable that attackers could somehow get incendiary devices to the walls and roof of your retreat.  The strongest walls are useless to you if you have a shake roof which the bad guys set on fire.

If you have wood on your walls or roof, then you’re vulnerable to this type of attack.  But if you have stone, adobe, metal, or concrete, you are safe from the threat of fire, too.

There’s a lot more to this topic – a lot more on both sides of the discussion – and we’ll come back to it again in future articles.  But for now, can we suggest that it is possible to envisage a viable future that doesn’t involve 500 sentries and soldiers, invisibility cloaks, and contradictory and morally unsound strategies.


The question of how to optimize one’s ability to survive against attacking marauders is a key and critical issue that you need to consider.  We’re not saying that every day will see you battling afresh against new groups of attackers – such events may be very rare indeed.  But, rare as they may be, they are not unforeseeable and may occur.

The problem becomes of how much resource to invest into anticipatory defenses.  A text-book perfect solution would require an impossible amount of manpower and resource.  You will need to compromise, accordingly.  But we don’t think there is safety in weakness; surely there is only safety in strength.

We’re reminded of the story about how to survive a bear attack if you’re unarmed.  You don’t need to be able to outrun the bear.  You just need to be able to outrun the people you’re with.

In our case, to survive an attack by marauders doesn’t necessarily mean you have to be either invisible or invulnerable.  It just means you’ve got to be less tempting a target than other people in the surrounding area.

Don’t get us wrong.  The best case scenario of all would be for your neighbors to be similarly hard targets, so that word gets out that your entire region is best avoided.  But first make your own retreat community strong; and only after that, work to help your neighbors on a basis of mutual support, too.

We’ve spent much of this article critiquing the letter we quoted.  But hopefully through the critiques, you can see implied positive strategies and approaches, and we’ll write more on how best to protect your retreat in further articles.

Mar 202013
A classic US military TA-312A/PT Field Phone.

A classic US military TA-312A/PT Field Phone.

As we’ve discussed in our article ‘Will there be telephone service after TSHTF?‘, it is probable that any event such as to activate your prepping survival plans will see a loss of both wired and wireless phone service.  We also predict the same failure for internet service, for similar reasons.

This will make your retreat electronically cut off from the outside world.  Oh – with the likely shortage or total disappearance of diesel and petrol supplies, you’ll become more physically removed from the nearest township too.

There will remain methods of communication, which we’ll discuss in subsequent articles in this series (particularly ham radio, and we’ve already advocated you should get a ham radio operator license) and of course other methods of transportation (or of fueling your current vehicles) too.  But this article approaches one of the alternatives you have for communications in, on and around your retreat property.  Using Wired Phones.

The Pluses and Minuses of Using Wired Phones

Apart from smoke signals, semaphore, and other ‘low bit rate’ forms of signaling, most of your communications around your retreat property would be either by wireless telephony of some sort (CB or other walkie-talkie, ham radios, Wi-Fi devices or cell phones) or by wired phones.

As we never tire of saying, you need to plan for a low-tech ultra-reliable type of communications that you can be certain will survive any initiating events that plunge you into a Level 2/3 situation, and which will continue to operate during the period of that situation.  As lovely as wireless devices are, they are less resilient.

There is another downside to wireless communications.  They are more readily detected and monitored by unfriendly people.  What is the point of being obsessive about ‘Op-Sec’ in a dozen different ways if you are chattering away on walkie-talkies regularly every day, providing a huge big electronic ‘homing beacon’ for unfriendly people to zero in on.  With scanning radios nowadays being inexpensive, readily available, and easy to use (for example, the $100 Bearcat handheld scanner listed on the many pages of scanners at Amazon, here) you have to assume that any radio transmissions you are emitting will eventually be picked up by people who may not have your best interests at heart.

Wireless devices also need batteries.  Sooner or later, you are going to run out of batteries, and/or your rechargeable batteries will wear out.

In comparison, wired phones are much more secure and harder for unwanted third parties to eavesdrop and listen in on.  They are generally lower tech and probably are more likely to be repairable if they develop a problem.  They might also require power, but they are probably much more forgiving about the type of power and the exact voltage they’ll operate with than is the case with a wireless device.

But a wired phone is not something you can have with you, all the time, everywhere you are located.  You need to have wiring run to each place a phone is placed.  And the wires are somewhat vulnerable to accidental or deliberate damage, although it is true your radio signals could also be deliberately jammed (all an enemy would have to do is to transmit on the same frequency as you any time you started a transmission, which might cause your transmission to be displaced by his).

Overall, if you are asking yourself the question ‘Should I prepare for wired or wireless communications at my retreat?’ you are probably not asking the correct question.  Ideally, you should have both.  Where possible, you’d use wired communications, but also have the ‘safety blanket’ of a wireless device with you for emergency communications.

Note that emergency communications might occur from you to other members of your retreat community, or equally likely, in the other direction from them to you.  Emergency communications don’t only involve ‘Help, we are being attacked’ type scenarios.  There are plenty of other emergencies and high priority reasons for calling someone else, and many of those scenarios won’t see either you or the person needing to contact you being at a wired phone.

So in the balance of this article, we look at issues to do with a simple type of wired phone – the field phone.  We’ll also be publishing articles on other communication options subsequently.

What is a Field Phone?

There is no formal definition for what a field phone is or is not, other than a vague expectation that it is a rugged device and probably of military origin.

When we talk about field phones, we are referring to very simple basic analog phones, although note that the latest military field phones are sophisticated digital devices.  There is nothing wrong with these at all, but they require more support and high-tech infrastructure than very low tech analog devices and from a prepping perspective, we are best advised to keep it as simple as possible.

The simplest phones of all require no power of any sort – no mains power, and no battery power either, because they are sound powered.  Slightly more sophisticated field phones are battery-powered, either from batteries inside each phone set or by batteries at a central switching location.

Field phones are connected to each other and to switching points via ordinary wire (rather than coax cable).  Some phones use two wires, others use four wires.  Two wire phones are typically a ‘simplex’ type of operation where only one person can be speaking at a time (like using walkie-talkies); four wire phones permit ‘duplex’ operation with both people speaking simultaneously.

Field phones are generally not equipped with dial pads and generally are not connected to any type of automatic switching exchange.  They certainly could be equipped with such capabilities, and be connected through an automatic exchange too, but as the sophistication of the phones and the required ‘central office’ support equipment increases, we feel we are no longer talking about ‘field phones’ which, by definition, should be thought of as very simple devices with limited capabilities.

There is no reason why you couldn’t create your own automated private exchange if you wish to do this – there are plenty of ‘off the shelf’ systems that you can buy for varying amounts of money, and with varying features, and you might validly wish to add a small private exchange to your retreat as well.

But the more sophisticated you make your communications, the greater the vulnerability they present.  They become more maintenance intensive, they become more energy intensive (requiring good quality electricity) and they become more EMP-vulnerable (phone lines will act as antennas to funnel and magnify EMP energy into the phones and other devices they are connected to, making phones and phone switching equipment very vulnerable to EMP effects).

There is also no reason why some field phones could not be connected – either directly or through your own branch exchange/switch, to the public phone network as well.  But you’re running into the danger of ‘over-engineering’ your situation and your solution.  Field phones are designed to be simple in form and simple in function.

At the other extreme to the latest multi-feature digital phone, you end up with a sound-powered phone.  Sure, it does nothing other than transmit voice to another person, but there’s almost nothing that can go wrong with it, and the few things that might go wrong can generally be repaired without any specialty high-tech tools, equipment, or parts.

Some things are common for all field phones – especially issues to do with how you wire them.  We consider these issues in this article; in another article we talk about the different types of field phones you can choose between.

Wire for Field Phones

Unlike wire for data or radio frequency circuits, field phone wire doesn’t need to be shielded, and doesn’t require any other special properties.  It just needs to be insulated and suitably strong for however you’ll be laying it.

Field phones can operate on pretty much any type of electrical wire at all.  The larger the gauge of the wire, the less the resistance and the longer the distance you can have between phone sets, especially with sound-powered rather than battery-powered phones.

The ‘entry level’ least expensive and arguably most common type of wire for military field phones is the WD-1/TT or WD-1A/TT single pair multi-strand wire.  It is lightweight and inexpensive, and you can sometimes find it for sale on quarter mile or longer reels.  There are also plenty of other types of mil-spec wire (with better conductivity, but greater weight and higher cost) and there’s no real need for the wire to be mil-spec anyway.

Four Wire vs Two Wire

If money allows, whenever you run one wire, run two or three, because you’ve no idea what you might not want to have in the future, and it is very much easier to run multiple wires at the same time than it is to redo the whole exercise and run more wires later.

In the case of  phone wiring, this means that even if you’re only planning on using a single wire pair type phone system, you should still make a point of running two pairs or four pairs of wire everywhere.  Who only knows what you might not end up using the additional pairs of wires for – you might upgrade your system to a four wire phone system, you might use the wires to run some power, or for remote metering, or who only knows what else.  Or maybe one of the wires breaks and you can then switch over to another spare wire.

Of course, it is one thing to be running multiple pairs of wire over short 100 ft distances within your retreat.  The extra cost is minimal.  But if you’re running a one mile line from one end of your property to the other, or a five mile connection to your neighbor’s retreat, then the cost of doubling up on your materials becomes more appreciable and you might have to compromise between what would be ideal and what is feasible.

Comparative Efficiencies of Different Wire Types

The length of wire you can run is limited primarily by the resistance of the wire.  Resistance is determined by the type of material, the thickness of the wire, and the length of the wire.

In general, copper is the best conductor of electricity (ie it has the lowest resistance), with aluminum as second best, then iron, then steel.  If copper has one unit of resistance, then aluminum has about 1.6, iron has about 6, and steel has about 8.5 units.

To put that another way, for every 8.5 ft of copper wire, you can only have one ft of equivalent thickness steel wire; or for every 1.6 ft of copper wire, you can have one ft of aluminum, and so on.

Another way of looking at it is that to have the same resistance, you must have a steel wire nine times thicker than a copper wire, because the larger the thickness or diameter of the wire, the better the conductivity.  On the other hand, the thicker the wire, the heavier it is, which poses problems if stringing it up between poles, and adds to its cost, no matter how you are running the wire.

Several different sources list comparable effective distances for TA-312 phones depending on the type of wire they are being connected together with.  The same concepts apply to other phones too, of course, such that if a phone’s range with one type of wire is twice as long (or twice as short) then it would be similarly twice as long/short for the other wire options presented as well.

Here’s the table for TA-312 phones (source – alas, the company that lists the phones no longer makes/sells them – I checked in March 2013).  As you can see, the practical working distance lengthens dramatically as the wire thickness increases.

WD-1/TT –  35 Km (22 miles)

Lead Covered Cable (19 Gauge) –  48 Km (30 miles)

Open Wire Line (W-2 #14 AWG copper, 0.064″ diameter) –   370 Km (230 miles)

Open Wire Line (W-74 #12 AWG copper. 0.081″ diameter) –  837 Km (520 miles)

How to Run Your Field Phone Wire Outside

Wiring for inside your retreat is a relatively trivial issue.  You’ll probably have it in the walls and ceiling and terminating in wall jacks, just like for regular phone and data wiring.  But how you run your wire outside is a more complex consideration.

The first consideration is security.  If you don’t want your wire to be obviously exposed, then you’ll almost certainly have to bury the wire to obscure and protect it.  An exposed wire poses several security threats.  First, it could be damaged/broken.  Second, it could be followed, perhaps helping an unfriendly visitor to locate any remote observation posts you might have.  Third, it could be tapped into, allowing unknown parties to listen in on your conversations.  And fourthly, a person might connect a high voltage device in series or parallel with the line, probably destroying whatever devices were connected at either end.

So, for security purposes. a buried line is better than an above-ground line.

Buried lines can be both more vulnerable and less vulnerable to accidental damage.  There is a risk of someone digging through the line, or perhaps as part of plowing a field also damaging the line.  Gophers and moles can be a problem, too.  Over time, tree roots may damage lines.  If a buried line is damaged, it can be more difficult to locate and repair the damage that with an above-ground line, unless you have a sophisticated test device that will tell you the approximate distance to where the line damage is located.

If you are running below-ground wire, you don’t need it in conduit, although that would enhance its protection appreciably, and so if budget allows, we would recommend you to do so, and particularly if you anticipate potential mole/gopher type challenges.  We suggest that one way to protect below ground wire – and to conveniently locate it again if you need to – is to run it alongside fence lines.  Usually any plowing or other working of the ground doesn’t go hard up to the fence line, so your wire is more likely to be undisturbed.

On the other hand, above ground lines are far from bullet-proof, either.  Indeed, there’s a vulnerability in that expression – there’s a danger of idiots capriciously or maliciously shooting at your lines just for the fun of it.  Depending on how you are keeping the lines above ground, if they are strung from tree to tree, you have obvious problems in the wind.

The only good thing about above ground wires is that it is easy to trouble shoot them and to repair them if (when) they break.  Generally we recommend below ground wiring.

If you have below ground wiring, we’d suggest that, where appropriate and possible, you either have inspection and access traps to allow you to easily access the wire or simply run the wire up above the ground on a post then back down below ground again.

If you run the wire in direct lines between traps or posts, that will help you follow its path if you need to dig it up to repair it in the future.

The traps or posts also provide access points where you can connect phones.

Fencing Wire for Field Phones

If you have a wire fence, why not use the fencing wire to carry a phone signal, too?  That is certainly an option.

Typical fencing wire is made out of zinc coated steel, and is 12 – 12½ gauge in diameter.  A 500 ft length of 12 gauge copper wire has a resistance of 0.77 Ω, a similar length of steel wire has a resistance of about 6.6 Ω (source).

Or, to express it another way, the resistance you’d encounter with 100 ft of WD-1/TT wire would be about the same as you’d encounter with 140 ft of fencing wire.

Using fencing wire for your field phones also has the advantage that you can tap into the circuit any time you are close to the fence line.  It is semi-secure, being ‘hidden in plain sight’.

If you were going to do this, then assuming you have a more than two wire fence, we’d recommend connecting the top wire and the third wire together for one part of the phone two wire pair, and the second and fourth wires together for the second phone wire.  Every so often, you should run wires connecting the electrically twinned/joined together fence wires.  This makes the double wiring more fault tolerant.

Doubling the wires this way not only halves the resistance (so then 280 ft of doubled fence wire would be the same as 100 ft of WD-1 wire), but also gives you some redundancy – one of the two wires can break and the other one still remains in place.  And by using only the top wires, the bottom wire (in a typical five wire fence) is left untouched, with this being the one most likely to be contacted by grass and other vegetation that might otherwise cause some of the current to ‘leak’ out.

If you only had three usable strands of wire, we’d recommend that about half the time, the third wire be linked to one of the two wires and the other half the time, it be linked to the other of the two ‘main’ wires.  That way it gives you a reasonably balanced/averaged resistance on both sides of the two wire line.

We would recommend using the middle wire as the one which alternates between sharing the signal with the wire above it and the wire below it.  That way, if you wanted to connect a field phone up to the fence wires, you always know to use the top and bottom wires and to ignore the middle wire.  It doesn’t matter if it is sharing the top or bottom wire, wherever you are.

Clearly, if you came to a gate, you’d then need to have ‘normal’ wire running down from the fence posts, under the entrance/gateway, then up the other side again.  And anywhere you had joins in the wire, you’d want to make sure the two lengths of wire had plenty of contact between them to create a good electrical connection.  In general, it would be preferable to run your fencing with as few joins as possible.

Wiring Topography and Strategy

There are several considerations and different ways to run your wiring.  In its simplest form, you have a simple single pair line running all around the place, and you can connect phones on and off this single pair line anywhere you want to, any time you want to.  Simple sound powered phones will get quieter and quieter for each extra phone currently connected (in parallel) across the wires, so that is a limitation, and there is a similar (but not so severe) type of limitation for battery-powered phones too, but for a quick and easy initial wiring layout, this works just fine.

If you have multiple phones on the one circuit, then anyone can pick up their phone and hear what other people are saying, and there has to be some sort of signaling protocol so a person calling another person can make the call request in a manner that doesn’t cause everyone to simultaneously rush to pick up their phone, only to find that the call wasn’t for them.

There is a variation on the single length of circuit concept, which is to make it into a loop.  This makes the circuit fault tolerant – you can have a break in the loop occur somewhere and the circuit will still work because the current simply flows the ‘other’ way between the devices.

This also makes a nice way of managing your circuit – you can have a test point on each of the two wires that is a break in each wire.  Normally you have the breaks joined together, but you can open up the test point and check for continuity/resistance in the circuit.  You’d get a very different value if a break in the line had occurred than if the line was still okay in both directions – although note that this value will vary depending on how many phones are also connected in parallel across the line and where they are located.  Best to do the test with as few phones across the line as possible.

A more sophisticated system has a star type of shape.  A central point – somewhere in your retreat building, probably, has multiple lines feeding out to different locations, with phones being connected on these multiple lines.  When someone calls on the remote phone, it rings at a switchboard in your retreat, and when someone answers, they can then either talk to the caller or connect them to one of the other phones if the caller wished to be switched to another person on another circuit.

The benefit of this type of system is that you can have multiple conversations simultaneously, and happening separate to each other, rather than having everyone simultaneously using the one circuit and struggling to get a word in edgewise.

In reality, you’re probably not going to have – or need – an extensive phone network.  You might have one phone in the barn, a ‘traveling’ phone that people can take with them when they are working in the fields, maybe another phone as a ‘gate phone’ that visitors can use to call to you at the retreat from your property boundary/gate and ask for permission to enter, and maybe another phone in an observation post.


Good and convenient communications simultaneously become more essential and more difficult in a future ‘grid down’ situation.  They are more essential because you need to live your life more efficiently, and good communications is an essential part of coordinating your life and your activities with those of the other people in your community.  Good communications are also an essential part of your retreat’s security program.

But the ‘grid down’ nature of a future Level 2 or 3 situation means you have to provide your own solution to your communication needs.  We recommend you adopt both wired and wireless communication services, and in this article we have given you some of the information you need to install a wired field phone type system.

Mar 102013
This laser rangefinder can instantly display distances out to almost one mile, and also provides ballistic data for the long distance precision shooter.

This laser rangefinder can instantly display distances out to almost one mile, and also provides ballistic data for the long distance precision shooter.

We’ll be writing about the ‘old fashioned’ way of locating your secretly buried cache shortly, but wanted to also write, separately, about using high-tech tools when first establishing where a buried cache is, and then subsequently locating it again later.

There are three high-tech tools that some people might consider useful for locating their cache.  The first of these is a GPS unit, the second a laser range finder, and the third a metal detector.

All three devices have pluses and minuses, and in particular, we do not recommend GPS units.

The problem with such tools is simultaneously also their strength – they are high-tech gadgets.  They rely on batteries, and if they fail, you’ll almost certainly not be able to repair them.  If an EMP event occurs, they may be destroyed by the EMP effects.

We’re not saying you should totally ignore these three devices, and if they are in a suitable situation where they can work well, they’ll massively simplify your task.  But we are saying you should supplement them with lower tech calculations as well.

GPS Units

GPS units can be accurate, but usually not quite as accurate as you might think.  The accuracy which some GPS units show is not the complete calculation, it is the theoretical best case accuracy and fails to allow for some of the other fudge factors that affect GPS accuracy.  As a rule of thumb, double the imprecision it shows.

So if the device is telling you it is showing your location to within 12 feet, it is probably accurate to within 24 ft.

The most accurate units have a WAAS capability too – these are ground stations at fixed locations that provide additional reference location information in addition to the satellites in the sky above.  If your GPS is WAAS enabled, it will give very much more accurate information – sometimes locating you to within a yard or so of your actual location.

An earlier type of GPS improvement, known as DGPS, has largely been superseded by WAAS.

There is a further type of GPS improvement, probably used by your cell phone, which combines GPS information with location information from cell phone towers and possibly even known Wi-Fi locations too.  This information is primarily used to more quickly get a ‘first fix’ for where you are, but may also assist in improving accuracy too.  This is known as Assisted GPS, or A-GPS or aGPS.  Due to the reliance on many additional layers of data sources, and the expectation that you’ll be in a less dense area with fewer of these additional data sources, we expect that aGPS would be the first service to fail WTSHTF.

There are also special GPS receivers such as some surveyors use, which use additional signal processing techniques to create a more accurate position, potentially enhancing accuracy to as close as 3″ or so.  These are very expensive, of course.

The accuracy of a GPS is a ‘double whammy’ because presumably you are first making a note of your cache’s location by using the GPS receiver, and then subsequently looking for it with a GPS receiver, too.  So perhaps your initial location was 24 ft in error, with the real location being 24 ft north of you.  Then when you are attempting to return to the spot, the location error is now 24 feet in the opposite direction, so when you think you’re exactly at the location, you’re actually 48 ft away.  Even more misleading, the GPS might be showing a 12 ft accuracy in both cases, but you’ve ended up with the cache some 50 ft away.

Digging up a circle with a 50 ft radius involves 7850 sq ft of digging.  That’s a lot.

You can help improve the GPS’s accuracy by taking multiple readings, each reading an hour or two apart from the preceding one, over several days, and averaging the results.  This would give you readings from different alignments of different satellites, with different propagation delays, and would give you a more accurate average location.

This is helpful when recording the cache location in the first place, but you probably don’t have several days of spare time to leisurely plot an average position when the time comes to dig it up again.

There’s another reason to avoid relying on GPS units.  It is far from impossible that in a post-WTSHTF scenario, the constellation of GPS satellites may have been degraded or even completely destroyed.  In other words, GPS might no longer be available at all.

Even if sufficient of the GPS satellites and their signals remain, we’ll guess that the ground station corrections that are continually being fed into the satellites to update exactly their orbits and locations will cease, meaning that the accuracy of the GPS service will steadily degrade.  This degraded accuracy will not be apparent on your unit, but it will be happening; maybe only a few inches every day, but in a month, that could be another 10 ft of inaccuracy on top of all the other ever-present inaccuracies.  In three months, it might be 30 ft, and so you’re starting to reach the point where the GPS is becoming unhelpful rather than helpful.

GPS receivers also require a reasonably unobstructed view of as much of the sky as possible.  Dense foliage and tall trees will reduce their ability to accurately receive signals from as many satellites, which will degrade the accuracy of their position calculations.  A nearby hill would also block some of the satellites.

By all means take an averaged GPS fix as one of your multiple ways of recording your cache location, but consider it merely a tool to get close to where the cache is and then use other methods to exactly find it.

Laser Rangefinders

Laser rangefinders are one of three different types of range finders available – the other two being optical and ultra-sonic.  It is perhaps helpful to quickly consider these other two forms of range finder before concentrating on laser rangefinders.

Optical rangefinders can be useful, and are gloriously low-tech.  But to give any type of useful accuracy, they need their two viewing windows to be far apart, making them bulky, heavy and also very hard to find – they are not being made any more (as far as we are aware).

The way they work is such that the greater the distance they are measuring, the greater the error in their measurement.  The percentage error increases as distance increases, making the actual number of yards plus or minus become impractically large for the purposes of pinpointing a cache.  Furthermore, the units need to be regularly calibrated and all in all, a reasonable amount of skill is required to get best use from an optical rangefinder.

To given an actual example of optical rangefinder accuracy, here is the accuracy data that applies to a Wild TM-2 range-finder with a 31.5″ base (80 cm).  It’s best case accuracies are :

Accurate to within   0.05 m at 100 m (a wonderful accuracy indeed)
Accurate to within   0.5 m at 300 m (still workable)
Accurate to within   1.3 m at 500 m (starting to get a bit much)
Accurate to within   5.4m at 1000m (no longer very useful)
Accurate to within  21.5m at 2000m
Accurate to within  48.4m at 3000m
Accurate to within  86.0m at 4000m
Accurate to within 134.2m at 5000m
Accurate to within 193.6m at 6000m

This last figure has now become equivalent to a 3.2% error and of course useless for cache finding purposes.

Sometimes you might find an old ex-military range finder for sale; if you do and its price is low enough, it might be a fun thing to add to the pile of stuff you buy in the hope that one day it might come in useful for something, even if you’re not exactly sure what that use might end up as being!

Ultrasonic rangefinders are okay for indoor short distances, and typically max out at about 60 ft.  They are not so useful outdoors.

Laser rangefinders are the best solution for outdoors, and unlike optical rangefinders, their accuracy can/should stay the same, in terms of the plus or minus number of feet or yards, which means their percentage accuracy is actually improving, as the distance increases.

They are decidedly more accurate than any other type of rangefinder and also superior to most ‘normal’ GPS units, and unlike the GPS receivers, don’t rely on the reliable ongoing availability of a radio signal from somewhere/someone else.  They’ll calculate a distance, sometimes out as far as 1000 yds, between where you have the unit and a far away object that will reflect and return the laser signal from the unit.  The better the reflecting surface, the longer the range the unit is capable of, including sometimes greatly in excess of the unit’s maximum claimed range.

Military type units have even longer ranges, sometimes extending out beyond 10 miles (the distance to the horizon is only about 3 miles, so this is about as long a range as you’d ever be likely to need for most purposes not involving field artillery and other stand-off weapons delivery systems. Smile

Civilian units, usually sold for hunting or golf purposes, typically have an accuracy of within one yard; some of the new units are now getting reliably accurate to half a yard (18 “).  Sometimes the accuracy gets less exact as the range increases, although in theory that shouldn’t really be the case for most normal distances.

A laser rangefinder is certainly a very fast and easy way of taking multiple measurements for distances from objects, as long as the objects are suitably reflective.  If you’re in the middle of a field and can take measurements off fence posts on four sides, for example (perhaps with metal strips on them) you’ll quickly establish a very small zone beneath which your cache lies.

This obliquely indicates a requirement for a rangefinder to be useful.  There will need to be relevant landmark objects that you can measure distances to/from in several different directions, so as to establish the location of your cache.  If you are in an open field with nothing visible for a long way in any direction – or, for that matter, in a forest surrounded by identical trees – then any type of rangefinder would not be as useful.

On the other hand, do keep in mind that their accuracy is probably only within one yard, whereas measuring tapes, over reasonably short distances (ie one full tape length, perhaps 400 ft) are going to give you an accuracy of a few inches.  If you have some sort of probe (or metal detector – see immediately below) that you can use to quickly test if your cache is underneath you, then a yard or so is perfectly fine; but if the type of covering above your cache doesn’t allow for a thin metal probe, then you probably would appreciate greater accuracy from a tape.

The problem with laser rangefinders is they require batteries and are vulnerable to EMP effects.  They can also be weather dependent – if it is raining or foggy or snowing, their range will drop and maybe they’ll cease to function at all.

By all means, use one, but make sure you have backup tapes as well.  Expect to pay appreciably over $100 and up to $1000 for a very good ‘industrial’ grade laser range finder (with longer range, greater accuracy, more features, and stronger laser pulses that will bounce back off a wider range of objects).

Some laser rangefinders come with a sophisticated set of ballistics calculations to help you with long-range rifle shooting.  This can be invaluable if you anticipate the need for long distance precision shooting and have suitable rifles that give you that capability.

Needless to say, Amazon offer a good selection of laser rangefinders.

Metal Detectors

A metal detector can help you quickly locate your cache once you know its general location.  Depending on how much metal is buried and the type of soil it is in, a good metal detector will uncover objects as much as 15 ft – 20 ft beneath the surface.

This is both good news and bad news.  The good news is that it is tremendously helpful if you can use a metal detector to find your cache without having to dig up hundreds of square feet of ground.  The bad news is that your cache is vulnerable to discovery if other people decide to go looking for it with a metal detector too.

This page has an excellent explanation of metal detector capabilities.

If you were wishing to be really secure, and if you were anticipating organized searching for your cache, you’d probably deliberately place metal objects randomly all around likely areas that searchers might go looking for your cache, and you’d probably choose objects that looked ‘innocent’ like they could have been placed there by accident.  Of course, this would also destroy your ability to use a metal detector yourself to find your cache, so you’d have to decide which was the more important to you.

Although a good metal detector can cost over $500, it is probably a helpful tool to have – and, who knows, you might find yourself using it to, in turn, detect other people’s caches, too!


Although you shouldn’t rely on them as your only ways of locating your hidden buried cache, a laser rangefinder and a metal detector can make zeroing in on your cache a quick and easy process (assuming you have specific identifiable objects within half a mile or so on several directions that you can bounce laser beams off to triangulate your position).  Both items will cost some hundreds of dollars each, so they may not be the highest priority items on your wish list, and of course, until such time as you are about to start burying caches, you have no need for them (at least in this context).

A GPS can also help, but it is less reliable and probably less accurate than using a laser rangefinder.

Mar 042013
Carbon dioxide (pictured) and monoxide meters are an important safety precaution if you plan on having any type of fires indoors.

Carbon dioxide (pictured) and monoxide meters are an important safety precaution if you plan on having any type of fires indoors.

So there you are, all hunkered down in your retreat.  The temperature is below freezing outside, but you’re happy and warm inside, both because your dwelling is ultra-insulated and also because you’ve a nice low-tech fire burning in the fireplace, providing a warm cheery ambiance and keeping you all nice and toasty.

That’s a nice mental image, isn’t it.  And if you have an open fire in an open fireplace, you’re probably okay, but many people – especially less well prepared people – when they find themselves encountering a situation where their normal source of heat fails, may resort to emergency methods of keeping warm that invariably end up with burning something in a way that isn’t a typical part of their normal living.

The problem is that if you have a fire in an enclosed area, what happens to the products of the fire’s combustion?  The smoke and toxic gases, carbon monoxide (CO) and carbon dioxide (CO2)?  If they have nowhere to go, or aren’t being vented at the same rate they are being produced, you will start to get accumulations of these products.  And that can be a bad thing.

About Carbon Monoxide and Carbon Dioxide

Carbon dioxide is naturally present in the atmosphere at a concentration of about 390 parts per million (by volume; by weight the measure is about 590 parts per million, but most measurements use the volumetric method).

People naturally produce CO2 as an output gas from breathing (assuming we breathe in air with almost no CO2  present then about 4% – 5% of the gas we breathe out is CO2), so any type of enclosed space with people in it starts to have elevated levels of CO2, no matter if there are any fires in the room or not.  The smaller the space, the greater the number of people, and the less the amount of fresh air that flows into the space and the less the amount of stale air that flows out, the higher the CO2 level may become.  Normal buildings typically have anywhere from maybe 1500 – 5000 parts per million of CO2 in them.

When carbon dioxide levels reach 10,000 parts per million (ppm) – or a 1% concentration, more sensitive people might start to feel somewhat drowsy.  At 5% people start to experience shortness of breath, dizziness, faster heart rate, headaches and confusion.  Concentration levels over 8% start to become fatal.

So we are fairly tolerant of elevated CO2 levels and the body quickly recovers from an exposure to higher than optimum levels of CO2.

Carbon monoxide is a much deadlier gas.  Normal concentrations of CO in the atmosphere are about 0.1 ppm (measured by volume not weight – CO is slightly lighter than air, whereas CO2 is slightly heavier than air).  In a typical house, concentrations are perhaps in the order of 0.5 – 5.0 ppm.

Whereas a 1% level of CO2 causes many people no ill effects at all, the same level of CO would cause unconsciousness within a couple of breaths and death within 3 minutes.  And whereas a level of 2500 – 4000 ppm of CO2 is considered normal inside a building, that level of CO would cause headaches, dizziness and nausea in 5 – 10 minutes and death within 30 minutes.

OSHA says that CO levels should be kept below 50 ppm.

Detecting Carbon Monoxide and Carbon Dioxide

The good news is that the smoke/toxic gases such as you get from a normal open fire (we’ll oversimplify and consider the two as being the same) are readily detected.  When your eyes start to water, and you find yourself coughing, you know you’ve a ventilation problem, and you’ll be forced to do something to solve the problem.

But what say you are using a clean burning heat source such as a kerosene heater or even just running all the burners on your gas stove full on?  Then there are few or no smoke/toxic gas byproducts that you can readily detect, but the fire is still creating CO and CO2.  It has to – all fires create CO2 and most fires also create CO to a varying extent.  The better fed with oxygen the fire, the less CO; the more oxygen starved, the more CO.

Both of these gases are impossible for us to detect.  They are clear, tasteless and odorless, and cause no irritation on our skin or in our lungs.  They are silent but deadly killers.

The good news is that there are inexpensive and effective detectors for carbon monoxide.

The bad news is that carbon dioxide detectors are more expensive.  However, as a rule of thumb, if the smell of the burning fire becomes objectionable, then you need to do something about that for all reasons, including concern about possible CO2 buildup.  Many people choose not to worry about CO2 levels at all, and certainly our advice to you is to have a carbon monoxide detection/alarm system operational as the higher priority (and regular smoke detectors simply to detect fires as a safety measure too).

You can conveniently buy a wide range of carbon monoxide detectors on Amazon.  Your local hardware store probably has them on the shelf, too, although probably not in quite such a wide range of makes and models.

It is much more difficult to find carbon dioxide detectors, and a Google search typically brings up only carbon monoxide detectors.  This difficulty is made even worse by the propensity for some people to confuse the two gases, and so even when people talk about CO2 detectors maybe they actually mean CO detectors.

Here is one website that clearly does sell CO2 detectors.

Oh – one more important thing.  When buying CO and CO2 detectors, be sure to get ones which are battery-powered.  They won’t be much use to you otherwise, because in an emergency where you need to resort to alternative heating strategies, this almost surely means that you’ve also lost mains power.

Smoke Detectors Won’t Help

Note that smoke detectors do not detect either carbon monoxide or carbon dioxide.  Although there are two different types of smoke detectors (ionization and photo-electric) both work by detecting particulate matter rather than gas.  They are simply – as their name implies – devices that detect smoke, rather than specific gases or even heat concentrations.

There are some combo units that combine a smoke detector and a CO detector too, but you should not assume your smoke detector also detects CO – and being as how that makes it more expensive, if it doesn’t say it does, then it probably doesn’t.


If there is any expectation that you’ll be burning fuel indoors, it is prudent to have carbon monoxide detectors to monitor the CO levels that will build up from the fire.  Modern super-insulated buildings ‘leak’ less air, and so can trap CO much more readily than older drafty structures.  It is prudent to insulate your retreat and regular dwelling as much as possible to save on energy, both normally and in a crisis, and when you do this, it becomes prudent to add a carbon monoxide detector too.

Carbon dioxide is much less deadly than carbon monoxide, so adding a CO2 detector is less essential, but still good practice.

Jan 032013
This graph, typical of many wind turbines, shows power output (vertical axis) against wind speed for a typical wind turbine.  There is only a very narrow band of wind speeds suitable for measurable power generation.

This graph, typical of many wind turbines, shows power output (vertical axis) against wind speed (m/sec) for a typical wind turbine. There is only a narrow band of wind speeds suitable for measurable power generation.

One of the essential requirements of any retreat has to be some type of renewable energy source.

As we’ve stated elsewhere on the site, the ultimate and paramount issue in any post-WTSHTF scenario is availability of energy.  Almost everything else in your life is or will be energy dependent – certainly shelter, definitely food, and maybe even water too.  Whether the energy comes from yourself (worst case scenario), from hoarded supplies of energy sources such as propane and diesel (which are only good until they run out) or from other sources, sourcing energy is your most important issue.

There are two or three obvious renewable (or ‘free’) energy sources – hydro, solar, and wind.

Wind has some appeal to it, particular in its abstract form, and particularly from reading the glossy brochures, and in terms of cost, the capital cost per kW of generating capacity is very competitive with other renewable energy sources.  But there is a lot more to wind power than meets the eye, and most of the added issues are negative rather than positive.

To help you better understand wind power, we look in this article at some of the less talked about downsides of wind turbines.

Hydro is easily understood, and solar is not much more complicated.  If you’ve got an accessible flow of water dropping from a higher level to a lower level, you’ve a chance at hydro, and the more the sun shines, and the bigger your solar array, the more solar power you can hope for.

Wind Power Only Works in Some Winds, Some of the Time

But wind is a different matter entirely.  With wind power, you need wind speeds that are greater than the minimum which your turbine requires, but less than the maximum.  At greater than maximum speed, the turbine blades will ‘feather’ – they will turn into the wind and the turbine will cease to spin, and no longer generate electricity.  This is different to solar and hydro – there’s no such thing as ‘too much’ sun or ‘too much’ water.

There’s also less of an issue with ‘too little’ water/sun either – sure, no water means no hydro power generated, and so too does nighttime mean no solar power generated.  But the minimum amount of water or sun needed to start the electrons flowing is truly very low, whereas most wind turbines sit lifeless until wind speeds exceed somewhere in the 5 – 15 mph range.

So that’s the first disadvantage of wind.  Wind works best in a location with steady (rather than gusty) winds that flow regularly in the 25 – 40 mph range.  Not many of us have such locations.  Most of us have insufficient ‘suitable’ wind to make a wind turbine a sensible concept under any conditions.

Even if you do have a reasonably good location, you need to have a back up plan for when you have a ‘wind drought’.  We all know that just because a place averages so much rain in a month, that doesn’t mean it is guaranteed to rain an even equal amount every day, and the same is true of wind, too.  What happens if you have no wind, or too strong wind, for an entire week and are unable to generate any wind-sourced power during that time?  At least with solar, even the cloudiest day will still give you some power, but with wind, you could conceivably end up with a ‘wind drought’ that lasts a week or longer.

That’s a very big problem to confront.  Most solar systems are backed up by standby batteries, with the idea being that during the day, the solar cells generate enough power for your needs plus a surplus to be stored in the batteries, then when the sun goes down, you switch to the batteries for the night, until sunrise the next day.  Plus, with a bit of planning, you can shift your electricity consumption so that most of it happens during daytime and less of it happens at night, reducing the amount of power you need to store.  That only requires a 12 – 15 hour or so supply of stored power.

But what if you’re planning to be able to withstand a seven-day period with no wind at all?  You need at least ten to fifteen times more batteries (which – trust us – is a lot of batteries), plus the excess wind generating capacity to quickly recharge them.

Now, for the further bad news.  Even if you do have reasonably suitable winds in your area, there are two other problems with wind power.  Reliability/maintenance, and longevity.

Reliability Issues

Next time you drive past a ‘wind farm’ have a look at how many of the turbines aren’t spinning.  If the ones around them are turning, then the ones that aren’t turning have failed for some reason or another (that’s not to say that all the ones which are spinning are actually working properly either, of course – some electrical failures don’t result in the turbine blades stalling).  Depending on the location, the design of turbine, and the speed with which failed turbines are repaired, you’ll probably observe anything from one in 20 to one in 10 are not turning when they should be.

Think about that – if we say it takes on average 4 days for a failed turbine to be repaired, and if you see one in 15 turbines are not turning, that suggests that on average that every turbine is failing once every 60 days, and with four days down out of 60, that is a 93% uptime rate.

Okay, wind enthusiasts, let’s take an optimistic view if you prefer.  Let’s say only one in twenty turbines is failed, and let’s allow an entire week for the turbine to be repaired – that suggests the failure rate is once every 140 days, which is still nearly three failures per turbine per year.  That is a 95% uptime rate.

And, just to be fair, wind naysayers, let’s say one in ten are failed, and they can be repaired in two days.  That means an average time between failures of twenty days – not quite three weeks.  Ouch!

You should also remember that these turbines aren’t working 24/7.  Their duty cycle might be more like 8 – 12 hours a day – in other words, they are only working a third to a half of the time, and even at that low rate of application, they are still failing repeatedly.

In a ‘grid down’ situation and with the progressive loss of high-tech componentry and high quality machining, do you really want to rely on such maintenance intensive things as wind turbines for one of the most essential parts of your ongoing survival?  What will you do when you run out of spare parts?

Longevity Issues

The other dismaying thing is the total service life that you might get out of a wind turbine.  It has generally been considered that you can expect 20 – 30 years out of a turbine before it needs complete replacement.  But what if that’s not so?  What if you can only get ten years of life from it.  What happens when the turbine totally fails?

Here’s an article which reports that the actual life span of wind turbines in Britain is proving to be significantly less than was optimistically projected.  There’s such a huge lobbying effort behind wind power generation (in both the UK and US) that this type of data is unlikely to be widely reported or commented on, but go read the article and form your own conclusions.

It is probably okay to plan for a 25 year life for your Level 2/3 retreat’s power source.  But only ten years?  That’s not as long as you might think – the human mind tends to find it hard to appreciate the time to a future date, so as a way of appreciating it, think back ten years instead.  That’s probably not such an impossibly distant point in time.  And so neither is ten years into the future, either.

As a comparison, solar cells are also often rated vaguely for a 25 year or longer life, but unlike a wind turbine, that doesn’t mean that at the end of their rated life, they stop generating power entirely.  Assuming they don’t suffer ‘catastrophic failure’ (ie someone dropping a brick on them!) the output they provide slowly diminishes over time – generally about 0.5% every year.  So after 25 years, a solar cell array has lost only about 12.5% of its maximum power generating capacity.  This article points out that some solar cell installations are still providing 80% of their initially rated power after 40 years, and show no signs of failing.

Solar cells can easily outlast their owners.  Not so, wind turbines.

Integrating Wind Power into Your Total Energy Sourcing Strategy

You’re probably getting the feeling that we don’t like wind power.  That’s moderately correct – we love the abstract promise of wind power, but we’re not very happy with the present day reality.

We could be persuaded, however, to add a wind turbine or three to provide another semi-redundant source of power to our retreat, but as a supplemental ‘bonus’ power source rather than as a critical must-be-working source.  This not only give more total power, but also adds another fail-safe level of redundancy.

Maybe a ‘once in a thousand years’ hailstorm destroys a large part of your solar cell inventory.  Maybe your hydro dam breaks.  Maybe any one of many other catastrophic events occur, in which case you’d be very appreciative to have spread your risk and to have deployed some wind power too.

If you do choose to adopt wind power, we’d recommend deploying multiple wind turbines.  That way, when one fails, you don’t suddenly lose all your wind power.  You ‘only’ lose half (if you have two), or a quarter (if you have four) and so on.

Needless to say, you’ll need to have a truly impressive inventory of spare parts, and beyond that, a high-end machine shop to allow you to repair and rebuild damaged components as well as simply replace them.

You’ll also want to also add to your battery storage capacity, or deploy some other form of energy storage so that you can take the spare wind power, when it is available to you, and put it to some good use.


Wind power is a very specialized type of power that has many constraints and concerns associated with it.  The wind speeds with which the turbine will actually generate power are concentrated in a very narrow band.  The turbines themselves are very maintenance intensive and prone to failure on a regular basis.  And their total service life may be much shorter than originally anticipated and promised.

Wind power may be acceptable as a ‘top up’ source of power, particularly in our present world where the electricity grid has multiple redundant power sources and can manage even if all wind power was to fail simultaneously.  But we do not recommend wind power as a prime source of power in a retreat/off-grid situation.

If you choose to include wind power as an energy source, you’d need to reduce the impact of turbine failures by investing in multiple turbines – at least three, so that having one turbine go offline would only reduce your power by 33% or less, hopefully giving you still sufficient for your essential needs.  You’d also need an extensive inventory of spare parts, and a much greater reserve bank of batteries to tide you over sometimes lengthy periods when your turbine can’t generate due to the wind being either too weak or too strong.

Dec 262012
This four panel solar array measures 13.5' x 4.6', generates up to 920W of power, and costs $3500 (in Dec 2012).

This four panel solar array measures 13.5′ x 4.6′, generates up to 920W of power, and costs $3500 (in Dec 2012).

The ‘comfort’ level – some might say, the degree of advancement – of a civilization or life style can be closely approximated to its energy usage.

There’s a reason that we in the US are among the world’s largest consumers of energy, and it’s not that we’re wasteful.  It is because we enjoy a lifestyle that is generally better than most other nations around the world.  Just about anything and everything you do involves consuming energy.  Some of this energy consumption is obscured (for example, do you ever think of the energy consumed by shipping the 40 tons of goods we each require a year).  Some of it is assumed (for example, the energy that is required to make aluminum).  And much of the rest is taken for granted, even if energy used directly by you.

All of this ‘works’ for us because we are blessed with abundant and affordable energy supplies.

That will massively change in a Level 2 or 3 situation (see definitions here).

Life is both good and simple at present, and you seldom if ever consider the cost of the energy you enjoy.  And if you did want to, you could work out how much it costs to switch on a light, to run the television. to turn up the heating.

Well, perhaps better to say that in theory you can work out all these things.  Your utility supply company has a tariff, probably shown at least in part on every invoice you receive, showing the cost of each unit of power or gas you consume.  A bit of figuring and converting, and you can soon work out that, eg, if you’re paying 10c per kilowatt-hour (kWhr) for electricity, your computer is costing you 3.5c/hour to run, and the reading light in your bedroom is costing you less than a penny an hour, and so on.

These costs are generally so low that we don’t even think about them individually, although we might wince a bit when seeing our monthly or bi-monthly utility bill.

What will it cost us to do the same things if the grid goes down and if we have to live with only the energy we can make (or have stockpiled) ourselves?

The answer might surprise you.  Some things will be (sort of) free.  Other things will be so expensive that no amount of money will make them affordable (for example, an electric clothes drier).  Most of all, expressing costs in dollars and cents terms is no longer as relevant (because money, as an abstraction, will no longer be relevant).

Some Energy Might Be Almost Free

Let’s say you have some solar cells on your roof.  How much does that electricity cost you?  Sort of nothing.

Sure, it cost you a lot of money to buy and mount the array on your roof, and to buy a controller and run wiring and whatever else, but those costs are all now fully incurred.  So, in a sense, solar power is free, which leads to an obvious question and a necessary answer.

If Solar Power is Free, Why Don’t We All Have it Now?

The ‘variable cost’ of using the solar array you have installed for generating some power today might indeed be zero.  But while that cost today is zero, there was a substantial cost involved to install it in the first place, right?  You needed to buy the cells, install them, add electronic controllers, run wiring, patch them into your home power supply, and possibly set up a bank of batteries and regulators, too.

An accountant would also point out that sooner or later, the cells, wiring, controllers, and other related parts of the system will wear out, break, or in some other way fail and need to be repaired or replaced, so there are some future costs to be considered.

An accountant would depreciate or amortize the cost of the system over the total likely power generated during its life, and give you an average cost per unit of power as a result.

Furthermore, at present most of us enjoy amazingly inexpensive power from our utility companies.  The number of years it would take to pay for the up-front installation costs of a solar array can be substantial, and too long to make sense for many of us, in a situation where we are prepared to assume that we will continue to be guaranteed 24/7 access to unlimited affordable power, whenever we need it.

That is why everyone hasn’t rushed to buy solar arrays, yet.  But keep an eye on pricing – the payback time for solar arrays has been getting shorter and shorter, due to the massive reductions in the cost of the cells (thank you, China!) and the steady increase in regular utility-sourced electricity.  On the other hand, the US government has deemed that China has been ‘dumping’ solar cells into the US, and while you or I might be delighted at a chance to get bargain basement priced solar cells, and while you might think the greenies in the government would be delighted at China in effect subsidizing the US renewable energy movement by selling us product at below cost, that is, alas, not the case, and the government is looking at various trade sanctions to force China to sell them to us more expensively.

Anyway, back to the cost of solar.  These various accounting and costing issues are all correct, of course, but once you’ve installed and paid for a solar installation, then in terms of the actual incremental variable cost of using your solar cell array right now, the electricity flows with no extra money being spent by you, and with no need to ‘feed’ the solar cells with diesel or any other consumable.

About the only thing you’ll want to do is occasionally clean the cells, and even that is something you do at the same intervals, whether you’re using all the electricity generated by the cells or not.

So – from one perspective – this electricity is free.  Enjoy it while it lasts (which happily will probably be for 25+ years).

Some Energy Might Be Impossibly Expensive

Maybe you have an electric furnace, or an electric stove top.  Let’s say that one of these devices can take up to 10 kW of electricity when in use.  And let’s say that you can only produce 5 kW of electricity maximum from your generator set.

There’s nothing you can do.  No amount of money will get more electricity out of the generator.  You’re stuck.

Furthermore, how much does the energy created by your diesel generator cost?  There are two schools of thought on that, so please read on.

Some Energy Has a Very Different Historical and Replacement Cost

Talking about that generator – and let’s assume it is a diesel-powered generator – you know how much energy you get from the generator per gallon of diesel burned (we’ll say 10 kWhr per gallon which is a reasonably good rule of thumb to use).  You know that when you bought the diesel you are burning, it was costing you $4/gallon, so you know that each kWhr has an underlying cost of 40c.

But that is only correct if you can conveniently replace the diesel you are using, and at the same cost.  You are best advised to consider the cost of anything like this in terms of the replacement cost of the source fuel you are consuming, rather than in terms of the historical cost.

If there’s no more diesel to be had, then the cost of the diesel you do have has just gone up massively, hasn’t it.  What is the replacement cost of a gallon of irreplaceable diesel fuel?

You’ll need to start thinking of sourcing/creating bio-diesel for the future, or other completely different means of being able to generate electricity as and when needed, and you’ll need to consider what the costs will be and how sizeable the supply may be.

Note the phrase ‘as and when needed’.  That is the very significant difference between solar and wind power on the one hand, and a diesel generator on the other.  Solar and wind power only flows when the sun shines or the wind blows.  Much of our power needs would normally be later in the day and at night when it is cold and dark, and when we want to cook our evening meal, and this is a time when the winds typically calm down and of course, the solar cells stop entirely.

So a diesel generator and its diesel fuel can not be replaced by solar or wind power, unless there is some way of storing up the power so it can be used when it is needed rather than when it is generated.  The most common means of power storage – lead acid batteries – is clumsy and the batteries have finite lives, both in terms of years and also in terms of the number of charge/discharge cycles they can withstand.

The True Cost of Energy in the Future

Replacement cost is the true cost of energy in the future.  And when we talk about ‘cost’, we don’t mean dollars and cents.  We mean ‘How long will you have to work, what will you have to do, in order to create the energy you are about to consume?’.

We see a future where energy becomes the key measure of one’s ‘wealth’ and the means of measuring one’s energy value is the amount of time it takes to create the energy you have and use.  This will give you a meaningful way to appraise the appropriateness of any particular energy use.

For example, if running your electric dishwasher saves you 30 minutes of time, but if the work required to provide the power for the dishwasher requires two hours of your time, then who will want to use their dishwasher any more?  It just doesn’t make sense to work for two hours in order to save 30 minutes of time.

But if one hour of work provides you with light and video or audio entertainment for four hours, that is probably an acceptable ‘cost’ – assuming, of course, that you have a spare hour of time to allocate to creating that energy.

Which touches on the other part of this equation.  How much is your time worth and how much extra time do you have?  If you are locked in a desperate struggle for survival, all day every day, simply working your land to create food to subsist on, then you probably don’t have either the time to create the energy to power your home entertainment system or the spare time to then enjoy it in the evening.

Some things are harder to equivalate.  It is easy to say, in the dishwasher example, that it makes no sense to work for two hours to save 30 minutes, but what say you are instead considering ‘I have to work for two hours to increase the temperature inside by residence by 5 degrees for a day’?  Which is better?  More clothes and blankets and less work, or more work and more comfortable home temperatures?  Of course, that depends – if the ambient temperature is 40 degrees, you’d probably work to bring the temperature up, but if the temperature is already 65 or 70 degrees, maybe it becomes less important and other things take higher priority.

Nonetheless, a key measure of energy will become the number of man-hours it takes to create a given amount of energy.

Energy Opportunity Costs

So we’ve just said the key measure of energy ‘costs’ in the future is the number of man-hours it takes to create a given amount of energy.  Yes, that is true, but there is more to it than that.

Another issue is the ‘opportunity cost’ of any particular energy use.  By ‘opportunity cost’ we mean that you will typically find yourself in an ‘either/or’ situation – either you use some energy for one thing or for another thing; whereas at present we seldom have to choose, and can happily choose ‘both’ as our preferred option, that will not be the case in the future.

So you might find yourself with ‘low cost’ energy (eg solar) but with insufficient of it to power everything you want.  You then have to decide on an either/or basis – either I can use it for this or for that – and the value/benefit of the thing that you don’t use it for represents the ‘opportunity cost’ of the energy.

Only when you can have every electrical appliance switched on at the same time does the opportunity cost dwindle down to zero.

At any given time, your energy cost needs to be considered as a measure of the most expensive energy source you are using for the final ultimate kWhrs of energy you are consuming.  Sure, some of the total energy being consumed might be ‘free’ solar, but the fact clearly is that if you reduce (or increase) your energy consumption, the thing that changes first is your use of your least desirable/most expensive energy.

Energy Covers More than Just Electricity

You need to consider your energy needs – and the solutions/sources for them – not just narrowly in terms of electricity.

While electricity – if in abundance and appropriately priced – has the benefit of being able to provide energy for almost any and all requirements, in a Level 2 or 3 situation, the chances are that you will almost certainly not has as much electricity as you would like, and the cost of at least some of the electricity you use, at some times of day, will be very high indeed.

Furthermore, by diversifying your energy sources, you reduce your dependency on a single source.

Some examples of non-electrical energy sources and applications would include solar heating for your hot water, a wood stove for interior heating (and possibly also to heat water too), or a piped hot water system for heating powered by a wood burning boiler.  A gas-powered cooking range is another example, as is a wind powered water pump, maybe even a water powered mill if you’re fortunate to be close to a river.  A horse-drawn cart is an alternative to a gas or diesel-powered wagon.  Hanging washing out to dry on a clothesline rather than using an electric tumble drier.

Your best energy sources will depend on where you live and what is available to you, and may vary depending on the season.

Some Energy Will Cost More at Some Times than Others

The law of supply and demand will of course apply much more strongly than it does at present, and particularly because it is very difficult to conveniently store energy at times when it is being generated in quantities greater than needed at the same time.  Lead-acid batteries of some type or another are the best choice for many people when it comes to storing surplus energy, but they have a very finite life and when that has expired, you will find it difficult to replace the batteries with new batteries.

A more promising technology is a flywheel with magnetic bearings.  This can store energy with little loss for 4 – 8 hours or even more – enough to tide you over an evening until the next day and the resumption of solar power generation.

However, as an interesting aside and an insight into the considerations you’ll have to think through when you become, in effect, your own electricity utility, although most of us pay the same amount for every kWhr of energy we consume, the underlying cost to the utility company can vary enormously depending on the time of day we are consuming it.

For example, a utility might have some of its power sourced from hydro-electric power, some from gas/oil/coal fired power stations, and some from nuclear power.  In addition, it has an agreement with other utilities to sell its excess capacity to them, and a matching agreement to buy excess capacity from the other utilities if/when needed.

Maybe the utility’s cheapest electricity is from its hydro stations, then its next cheapest from its gas-powered stations, then from nuclear, then from oil/coal, and its most expensive electricity is when it has to buy it in from other utilities.

At some times of day, the utility might be able to provide all the power needed by its consumers via its hydro generating capabilities.  But at higher demand periods, it has to ramp up its other power generating capabilities, and at peak demand, it might have to buy in more power, possibly at a cost of as much as ten times greater than its hydro-power.

A similar situation will apply to you in your retreat.

During the day, with the sun shining strongly on your photo-voltaic cells, you might be able to meet all your energy needs from the solar array(s) you have.  This is sort of ‘free’ energy, other than perhaps having an opportunity cost because maybe there is insufficient surplus to concurrently recharge up your lead-acid battery bank – power that you’ll need overnight when the sun has set.

If you have wind power, that too will rise and fall in terms of the amount available to you, and at times may be abundant, while at other times may be inadequate.

In an evening, you might have multiple sources of energy.  You might have a wood burning stove to provide warmth in your dwelling and perhaps to also heat up your hot water supply.  You might have a propane powered stove to cook on.  Electrical appliances might be powered by a bank of lead-acid batteries, and/or possibly by a diesel generator.

Your hot water might be solar heated, but if you use too much of it, you’ll either end up with cold water or need to use an additional energy source to heat the water until the solar heat returns the next day.

You might think that the wood for the stove is free, but just because you’ve not handed over cash to someone in exchange for the wood does not mean it is free.  You’ve had to first grow the tree, then you’ve had to fell it, cut up the logs into fireplace sized chunks, and transport it from where the tree grew to where your residence is.  All of that consumes a lot of your time and effort.

Adapting Your Lifestyle to Your Energy Sources

Many years ago, rural dwellers kept much simpler lives and schedules.  For example, they would tend to get up when the sun rose, and go to bed after the sun set.  This concept has been partially applied to the notion of daylight saving time which possibly saves a small amount of energy each daylight saving season, as well as probably enhancing our lives by matching our waking hours more closely to the daylight hours.

You need to adopt similar strategies in a Level 3 situation, and probably also in an extended Level 2 situation.  There are other things you can do as well.  For example, use electricity for tasks when it is most abundant – if you are fortunate to be able to power an electric washing machine, only run it when the sun is brightly shining (or the wind blowing) and you have an abundant inflow of electricity.

If you have solar heated hot water, plan your main hot water draws at times when the water is most likely to be sufficiently hot to use, and ideally when there is still a chance for the replacement water to be heated some, too.  In other words, take showers and baths in the afternoon rather than in the morning or at night (oh, and one of the first things to go will be our current ‘indulgence’ of showering/bathing every day and sometimes even more than once a day!).

Time your energy needs for cooking to an appropriate time of day that aligns with your energy source availability and chance your meal schedule to match.  If this means you have your main meal at lunchtime rather than dinner, so be it.  Many people do so already, and indeed, it is generally considered healthier to do so.  Some medical experts say that we should eat our food in a direct inversion of the way people often eat at present.  Instead of a small breakfast, medium lunch and large dinner, we should have a large breakfast, medium lunch and small dinner.

And, of course, set your sleep patterns so that you’re not ‘wasting’ daylight hours asleep at one time of day and then needing to use energy to create light at a different time of day.  Although lights are one of the smaller energy consumers, they are generally needed at a time of day when energy is most expensive (ie no solar) and so it is important to minimize your light requirements.

The Ideal Energy Source

If we were in a perfect world, we’d choose hydro-electric power as our energy source.  Why?  Because it is a 24 hour a day source of reliable power, limited only by the daily water flow and any seasonal reductions in water volumes.

But hydro-power requires lots of water and a sizeable drop in water levels to work.  As a rule of thumb, to calculate the power generation capabilities of a hydro station, ,multiply the water head in feet by the water flow in gallons/minute, and divide the answer by 10 to get the number of watts being generated.  In other words, with a 10′ head, you get one kWhr of electricity from every 60,000 gallons of water.  A greater water drop (ie head) would reduce the water volume required, and as a practical matter, if you have much less than 10 ft you start to have too little water pressure to effectively harness (about 8′ is currently considered the minimum).

Even if you have a possible water source on your property, EPA and other restrictions (both federal, state and possibly even county level too) may restrict your ability to take over any streams/rivers on your property, and therefore will constrain your ability to construct a dam and micro/mini hydro generating facility.  You’d need to carefully check this out, but if you have water rights to the stream, that is a good first step that may lead to approval.

Hydro electric power is characterized by high capital costs to create possibly a dam and the generating facility, but once it is in place, it then has of course no ongoing costs and is relatively undemanding in maintenance requirements.  A close to ideal source for after TEOTWAWKI – and, of course, noting the essential need to diversify risk in everything you do, you’d want to back it up with solar and other energy sources as well, ‘just in case’.

There are types of ‘in river’ turbine generators that you can simply drop in a river and use to extract some of the energy from the water that flows past, but these are very low powered units.  On the other hand, they might provide a useful source of power for night-times when your main solar sources become inactive.

Planning Ahead

When you design and build a retreat, you need to plan its design based not on the current energy abundant situation we enjoy today, but on an adverse situation in which we need to move to our retreat and become self-sufficient.

This means that a major focus on your retreat construction has to be energy efficiency.  Construction techniques that make no sense when energy costs only 10c/kWhr become much more appropriate when energy costs spiral to a future equivalent of, say, $1 or $2/kWhr, or the even uglier reality whereby you’ll be ‘energy poor’ and have insufficient energy for your basic needs, no matter what the cost.

Before you even start to design and construct your retreat, you need to apply these considerations to where your retreat will be located.  In a hot climate, you might prefer a sheltered area that doesn’t get so much sun, but in a cold climate, you might need an area with great southerly exposure.

Clearly the dwelling will need to be super-insulated, and built around its incorporated heat (and possibly cooling too) sources, rather than having them added on almost as an after-thought and as a low priority.  You might have to compromise some eye-appeal for functional survivability and energy efficiency.

For example, don’t run heating/cooling ducts through the basement areas or crawl spaces – run them through the living areas of the house.  You probably don’t need to heat or cool the basement and crawl spaces, but by keeping all the ducting inside your house’s living areas, there is no ‘wasted’ heating/cooling.

One happy coincidence – walls with enhanced insulating properties tend to be stronger walls in general, better resistant to hostile attack and adverse weather.

Here’s one resource to get you started on considering such things.  Here’s another, but it aims to merely enhance your home’s energy efficiency by 15% over a 2004 published standard – that’s massively underachieving in terms of what your objectives should be.


The biggest change in our lives, come a Level 2 or 3 situation, will be our transitioning from our current ‘energy rich’ lives to a future ‘energy poor’ existence.

At present, we happily never really need to consider about reducing our energy consumption, other than being motivated by a (probably misplaced and altruistic) desire to ‘save the planet’ by cutting down on our energy use, and energy is so cheap that most advanced energy-saving strategies fail to be cost-justified.

This will massively change when we have to create our own energy rather than have it appear, as if by magic, out of the sockets in the wall.

We need to plan and prepare for an energy-scarce future, and to take steps to reduce our dependence on energy so that we can still live comfortable lives, with massively reduced ‘energy footprints’.  We need to build our retreats based not on present energy costs, but on the future costs (and availability) of energy after TEOTWAWKI.

Solar is becoming affordable and effective, but only when the sun shines, and probably not for all of the energy-consuming devices in a typical house (unless you have a large budget and are in a very sunny location).  Additional energy availability for evening and winter times will be the biggest challenge for most people.

Oct 082012

Radiation is nasty, for sure. But it can be survived, if you know what it is, what to expect, and what to do.

One of the classic doomsday scenarios, often inappropriately given way more prominence than it deserves, is some type of nuclear event that results in a massive release of radiation.

We think this is one of the reasons why underground bunkers are so popular.  But as we’ve analyzed in earlier articles, underground bunkers are seldom a good idea for preppers.  By the time you get to the underground bunker, it might be too late.  And, assuming you got to the bunker in time, and survived whatever the event was, you’d find the underground bunker a very inconvenient living space into the future.  By all means stick a basement underneath your retreat, but don’t make a basement or bunker the entire retreat!

Let’s understand the nature of radiation and fallout risks – from that understanding can follow a better appreciation of what one needs to protect against and how to do so.  The two terms are sometimes used interchangeably, but they are importantly different.

What is Radiation

The term ‘radiation’ covers a lot of different things.  Light is a form of radiation.  So are radio waves.  But for our purposes, radiation can be split into two types.  The first type is relatively safe, and is termed ‘non-ionizing’ radiation, and this includes radio and light waves, plus heat, sound, and various other things.  Non-ionizing radiation is a type of radiation that isn’t thought to make changes to the atomic structure of things it comes into contact with, but it may cause other sorts of changes or side-effects (as you’ll know any time you stick something in a microwave oven, which uses non-ionizing radiation to cook the food you placed in it), so it is not necessarily completely safe.

Our discussion in this article however is about ionizing radiation.  This is radiation that can change the make up of the individual atoms in things it comes into contact with.  That is almost always a bad thing, and in particular, it can break up DNA in living tissues, which can lead to the formation of cancers.

There are five major and relevant types of ionizing radiation, termed alpha, beta, gamma, neutron and X-ray.  Cosmic rays (primarily protons) are also ionizing, but they are a constant thing that does not change with a nuclear explosion, and so we can ignore them for this article’s purposes.

Let’s consider the main properties of these five types of radiation (and for the nuclear physicists reading, yes, we have simplified things somewhat, but hopefully have not compromised the overall accuracy of the article).

Alpha radiation

Alpha particles are the same as Helium-4 nuclei.  They comprise two protons and two neutrons.  They travel at about 5% of the speed of light (ie at a speed of about 10,000 miles in a second) but they are very short range – they typically only travel a couple of inches in air, and can be stopped by a single sheet of paper.

Because of their short-range and low penetration, alpha particles are not much of a problem.

Beta radiation

Beta particles are typically electrons (if you wanted to be fastidious you could say there may be some anti-matter positrons briefly present too, but let’s not dwell on that).  They are typically very fast-moving, and can travel greater distances than alpha particles, and will penetrate further as well (which is sort of implied by their greater range, of course).  They will be blocked by about 1/10th of an inch of aluminum or other metal, or by an inch or more of plastic.

Gamma radiation

Gamma rays are ‘highly energetic photons’.  In case that doesn’t explain much to you, they are fast-moving things (they travel at almost the speed of light) with no mass and no electric charge.  This makes them hard to block, and they can penetrate a considerable distance through most materials.  As a simplification, the more mass of material between you and the gamma rays, the better the material will act to attenuate (ie reduce) the amount of gamma radiation passing through it.

Gamma rays have an effective danger range of only a few miles, by which stage so few will remain as to no longer be harmful.  Depending on the magnitude of the original explosion and the amount of gamma rays released, this danger range is anywhere from under one mile to perhaps three miles.

Neutron radiation

Neutron radiation is – as its name implies – a stream of the sub-atomic particles we call neutrons.  It is also fast-moving, at a similar speed to that of alpha particles.

This type of radiation is nasty.  When a neutron hits an atom, it can change the atom into a different substance, and it can change a stable substance into an unstable (and therefore radioactive) substance.  Neutron radiation of a given level is generally said to be ten times more damaging than gamma or beta radiation.  Oh – and did we mention that they also penetrate very well, requiring a substantial thickness of material to block them.

Water and concrete are good blocking materials.

Neutron radiation has slightly less range than gamma radiation.


X-rays are similar to gamma rays and are sometimes released as secondary radiation as part of a radiation event, but are not a primary product released by radioactive material, and so can be ignored for the purpose of this article.

The Shared and Relevant Characteristics of Radiation

The previous section looked at five different types of ionizing radiation, all of which is harmful to living creatures.  They share a couple of important properties – they are all very fast-moving (even the slowest moves at a rate of about 10,000 miles per second) and they are all very small – some are so small as to have no mass or size at all (yes, we know that doesn’t sound sensible, but it is what it is).

They also have moderately short ranges – generally less than 5 miles, and sometimes less than 5 inches.

A nuclear explosion will almost instantly release lots of radiation, and in only a second or so, not only will this radiation have been released, but it will have also traveled as far as it is going to go.  In other words, if you see a nuclear explosion, by the time your eyes have blinked from the bright flash, you’ve already received all the radiation you’re going to get from the immediate explosion itself.

Depending on where you are, that is either a good thing or a bad thing.

What is Fallout

So, what is fallout?  Fallout is all the ‘stuff’ that was in and around the bomb.  Some of this was radioactive to start with – by which we mean, it was emitting ionizing radiation.  Some of the rest of it has become radioactive, as a result of neutron radiation changing the properties of the elements and making them into new radioactive elements.  To be pedantic, you could term this ‘radioactive fallout’ but it seems to often be referred to merely as ‘fallout’, even though not all fallout is necessarily radioactive (but, to a greater or lesser extent, most of it is).

In the case of a bomb that is exploded in the air, most of this fallout material is simply the remains of the bomb itself.  But if a bomb is exploded close to, on, or in the ground, then the neutrons from the initial explosion will react with the soil and any other materials close at hand (buildings, cars, people, whatever) and will make some of that material radioactive, and the force of the explosion will blow all this material up into the air as well, massively increasing the amount of radioactive stuff up in the air.

So far so good.  Now for the ‘fall’ part of the word fallout.  All that stuff in the air is going to gradually settle back down to earth.  An air explosion will typically blow its remaining ‘stuff’ way up into the upper atmosphere, and it will spread perhaps all around the world and gradually settle, more or less evenly, over a huge portion of the earth’s surface.  This is actually a good thing – there is unlikely to be any massive concentration of radioactive fallout in any one place as a result.

But the ground and near ground bursts are very different.  Some of the material will be hurled up into the upper atmosphere, and will slowly fall down over the weeks and months that follow, all around the world, the same as air burst type fallout.  But some of it will only go up a relatively small distance and will fall back to earth more quickly (usually within 24 hours), and more intensely.  Depending on things like wind and rain, this material is likely to come back down to earth in the area downwind of the explosion, and perhaps spread out over 50 – 300 miles.

A ground burst not only creates a massively greater amount of radioactive fallout, but it deposits it more quickly and in a more concentrated pattern.  This is all bad.

Fallout particles range in size from less than 0.1 microns in diameter up to many microns in diameter.  They are dangerous because wherever they land, they are emitting whatever type of radiation it is they will emit.  They can potentially be breathed in to your lungs, and – for example – if you then have an alpha radiation emitter in your lungs, it doesn’t matter that the alpha particles only travel an inch or two and are stopped even by a sheet of paper, because wherever it is they stop, and whatever damage they then do, it will be inside you and to part of you.

Not only can you breathe fallout particles in, you can ingest them from the water you drink, and the food you eat.  Plus, the vegetables and animals you in turn eat or take milk from are doing the same things, and so your food may not only have surface contamination, but may have internal contamination too.  You can reasonably wash fallout off the outside of some food, but you can’t get rid of it once it has become a part of the thing, itself.

How Long is Fallout Dangerous For?

There’s no exact answer to this, any more than there’s an answer to the question ‘How high is up?’.  The danger life of fallout depends on several things – the level of radiation being emitted, and the half-life of the radioactive materials in the fallout.  Fall-out has a veritable soup of different radioactive substances in it, all with different properties.

The ‘half-life’ of something is the time it takes to reduce in activity by 50%.  Half-lives can range in duration from the tiniest fraction of a second at one extreme, to thousands of years at the other extreme.

To give an example of how half-lives work, let’s say there is a product with a 10 day half-life.  If it is emitting 1024 units of radiation a second at the start of the measuring period, then in 10 days it will be emitting half that rate, 512 units/second.  Now for the trick.  In another ten days time, it doesn’t use up the other half, and drop to zero.  Instead, it uses up half of what remains, so it loses half of the 512 units, and at the end of the 20 days, it will be emitting 256 units of radiation/second.

In another 10 days (30 days total), it will be down to 128 units of activity per second.  At the 40 day point it is down to 64 units, at 50 days it is 32 units, and at 60 days – two months – it is now down to 16 units.

So the rate of reduction of radioactivity slows down.  The first 10 days saw a drop from 1024 units of radiation a second down to 512 units/second.  But the ten days from 60 days to 70 days sees a reduction from 16 down to 8 units – not really much of a change at all.  Furthermore, it sort of never ever gets all the way to zero.  When it is down to 1 unit, the next half-life period takes it to 0.5 units, then to 0.25, and so on down and down but never quite reaching zero.

If the acceptable level of radiation is, say, 10 units/second, then at the 70 day point, when it is down to 8 units a second, it has become relatively ‘safe’, and at the 80 day point and only 4 units a second, it is even safer still, and at 100 days (1 unit/second) you sort of forget about it entirely.

The good news is that many of the most radioactive substances have relatively short half-lives – their half-lives are short because they are so radioactive.  So while you read about radioactive contaminated materials with half-lives of thousands of years, it is usually the case that these very long-lived substances only emit low levels of radiation.

Defending Against Radiation and Fallout From a Nuclear Explosion

Your best defense against the initial release of radiation is to choose your location carefully, so you’re not within range of any likely targets.  If you’re a ‘glass half full’ kinda guy, the ‘good news’ is that if you are within range of the initial radiation release from a nuclear explosion, that is probably the least of your worries.  You’ll probably be toasted to death from the heat, or crushed by the blast, long before the radiation kills you.

The bigger risk is the fallout from the blast.  Again, you should choose your location as wisely as you can.  As long as you can keep at least 20 miles from all air-burst targets, you’re probably going to be okay from air burst effects.  Unfortunately, the ground bursts are much more troublesome, because who is to really know which direction for sure will be downwind on the day?  You don’t want to be within several hundred miles of targets that are likely to receive ground bursts.

What types of targets will qualify for ground bursts?  Only specialized targets, because for general effect and damage, air bursts are much more effective.  But things like missile silos will definitely get ground bursts, and depending on their nature, other ‘hardened targets’ may also get ground bursts.

There’s another factor at play, too.  Fratricide and general errors, failures and mistake.  Not all missiles that are sent in our direction are guaranteed to explode exactly on their designated targets, and at the heights programmed into their warheads.  Some may explode high, others low, and some might go way off target.  Not only are ICBMs a little-tested technology, but routes over the North Pole are difficult to navigate, and with the very high re-entry speeds, even  a slight second of delay can mean a missile is way off course or too high or too low.  Add to that possible distortions caused by anti-missile events, and also what is termed ‘fratricide’ – the result of one missile’s detonation impacting on other missiles close to it, and a high intensity exchange of warheads could well end up with explosions going off hundreds of miles from where they were planned.

So the further away you are from anywhere that might receive any type of attack, the better you’ll be.

Now, for the fallout protection.  If you end up getting a bucket load of high intensity fall-out dumped on you, and survive the initial experience, then you’re just plain completely out of luck for the next some decades, possibly even hundreds of years.  Your only strategy will be to shelter until the fallout has all settled, and then to evacuate to a safer area, probably tens or even hundreds of miles away.

If you however get only a mild level of fallout, you’d be well advised to stay inside and to filter your air supply until the fall-out has done its thing and settled.

Your initial forays outside (ie to sample the area for radioactivity levels) should involve you wearing protective clothing (ideally exposing no skin at all), a breathing mask and goggles, and a decontamination process outside your dwelling prior to re-entering it, so you don’t bring in any radioactive material upon your return.

Opinions differ as to how long to expect radiation levels in fallout to subside – perhaps because different types of nuclear weapons, and different scenarios for their use, result in different mixes of radioactive materials, with different levels of radiation being emitted and different half-lives..  It seems that using three to five weeks as a prudent period to allow for levels to appreciably drop might be appropriate, and so you should factor the ability to survive, entirely inside, for at least twice that period of time, so as to be reasonably well prepared for such situations.

You should also be measuring radioactivity levels yourself, and keeping a record of them so you can try to see what the trend lines suggest (although this is difficult because there are a mix of different materials with differing half-lives, so there is no simple curve that you can plot and extrapolate).

Note also that radiation will probably not be evenly distributed everywhere on your property.  You’ll want to survey the property, and to map out ‘hot spots’ and safe zones, and to then keep away from the hot spots (and/or take steps to mitigate the dangers they pose) while concentrating your ongoing activities in the safer areas.

Beyond that point, practical considerations also intrude.  If it is winter, and there’s no need to be outside, then of course you can play it safer and stay inside more.  But if it is summer and there is work to be done outside, you need to decide what to do, and maybe rotate outside assignments between different people in your community, spreading the exposure more widely.

A Different Scenario – A Nuclear Power Plant Problem

The good thing about a bomb is that it does its work all in a fraction of a second, and after that fraction of a second, it is done and finished.  Sure, you might have to live with the consequences for a long time, but at least the initial event that created the problem has ceased.

But a nuclear power plant problem can be an ongoing issue, that releases nuclear material not just for a split second, but for hours or even days or weeks.  You may have ongoing releases of new material for an extended time.

Perhaps the best (worst?) example of such a scenario occurred in Japan in March 2011 at the Fukushima Daichii power plant in Japan.  An earthquake caused the working reactors at the multi-reactor site to shut down, and emergency diesel power generators started up to keep the cooling pumps circulating water through the power plant cores.  The subsequent tsunami flooded the generator rooms, causing the generators to fail, and without power, the cooling pumps stopped, allowing temperatures in the reactor cores to go dangerously high, with three reactors melting down.

The problems started on 11 March, and significant releases of nuclear materials continued for two weeks or longer (depending on where you draw the line on ‘significant’ releases), and material was still being released a month after the event started.  Here’s a great timeline.

It is probable that less radioactive material, in total, was released at Fukishima than at Chernobyl, but it occurred more recently, over a longer time line, and in full real-time view of the world’s news programs, making it a higher-profile event.

Furthermore, the Chernobyl disaster was relatively short-lived (pretty much all over and done with in less than a day), and we in the west only got wind of it (almost literally so) some time after the problem had been controlled, so there was less opportunity for angst and anguish.

There are a lot of variables at play with a nuclear power plant release of radioactive material.  It could involve any or all types of radiation, and it might be released into the upper atmosphere or instead have a short ride up and a fast ride down again, pooling in concentrated area.  Have a look at this map of contamination levels that were still in place in 1996, ten years after the event, to get a visual feeling for how strange the pattern of radiation concentration can be.

Try and locate up wind of nuclear power plants, and the further away you can be from them, the less risk you’ll run (although note the distribution pattern from Chernobyl where there was a relatively safe zone in the middle distance, with more dangerous areas both closer to the power plant, as you’d expect, but also further away, too).


Releases of radioactivity, whether from power plants and other accidental/peaceful means, or from nuclear weapon explosions, are definitely not a good thing, but they can be planned and prepared for, and generally, most times, can be survived as well.

As regards nuclear explosions, if you survive the blast and heat itself, you’ve also probably survived the initial release of radiation.  But the impacts of fallout are less predictable and will take place over a longer time.

You need a way to seal your retreat and filter the air you allow in, you need procedures to monitor and measure the radiation levels around you, and you need decontamination procedures when people leave your retreat, go into potentially contaminated areas, and then wish to return back into the retreat.

Interestingly, almost none of the challenges posed by radioactivity releases require, or are solved by, an underground bunker.