Hi Jim.
Just felt the need to re-emphasize the point you made with regard to
Mr. Yankee's ideas about an improvised fallout shelter.
First, I applaud his view that one should not count on being able to
pull together an adequate expedient shelter when the need arises. As
simple in theory as it seems, in practice, few would end up with a
shelter they would want to rely on to save the lives of their loved
ones.
Second, as far as the point you made, Jim, it is indeed very important
to over-engineer any sort of structure that will be bearing the loads
necessary for a fallout shelter.
I need to point out that I want to do everything in my power to encourage
folks to buy or build their own shelters, whether it is from us or
not. Why? I feel it's very possible that the number of adequate shelters
in the USA will go a long way toward defining our future viability.
So I always hesitate to discourage folks in any way when they talk
about what they feel are good, easy shelter ideas ... but really are
simply short cuts that as you pointed out could end up killing them.
To anyone thinking about this, if you're going to build your own fallout
shelter, then be darn sure it is built to last for decades under the
most stressful conditions you can imagine. (Better yet, under conditions
a structural engineer can imagine.) If it turns out you need to spend
any time at all in your shelter, you sure don't want to be thinking
about how you cut some corners to save a few bucks, or that you did
just enough to probably hold up when you have to start topping off
the loads.
A "for instance": There are a lot of arm-chair, Internet
shelter designers who like to propose grand designs for underground
shelters made of storage containers. Bad idea! They
may look great as you are backfilling and burying them, but they are
not built to
withstand subterranean forces. They will catastrophically fail at some
point--probably sooner than later. Believe me, if they would work,
there would be plenty of us selling them as bargain-basement solutions.
As I said, I want to encourage folks to do the best they can to provide
a decent shelter for their loved ones. It's important, and when you
get it done well, it's peace of mind that you can't otherwise buy or
manufacture. If you're going to do it at all, do it very, very well.
Besides the need for Mr. Yankee to think seriously about shoring up
his floor overhead and perhaps his walls, I'd ask him to try not to
get too clever with what it is that will serve as his shielding mass.
Salt will work, as will any material (including air), but the key
is how much will get the job done? I suspect that one would need a
whole lot of salt to provide the needed mass.
A quick rule of thumb many can benefit from when looking at how well
to shield their survival space: Shielding that reduces gamma ray intensity
by 50% includes .4 inch of lead, 2.4 inches of concrete, 3.6 inches
of packed dirt or 500 ft of air. One should aim for 10 times the halving
protection using these guidelines when constructing your fallout shelter
... such as 36 inches of earth or 24 inches of concrete or 4 inches
of lead (not practical) or say, 12 inches of concrete and 18 inches
of earth. This is a minimal level of protection, I feel. Of course,
overkill in shielding is great as long as the supporting structure
is built to withstand it. - Vic at Safecastle
Hi Jim,
I applaud Mr. Yankee for starting to think about constructing a Fallout
Shelter. Over the past few months, I have been giving some consideration
to the very same thing. But, after researching various “expedient” shelters
such as the one described by Mr. Yankee (available in FEMA publications),
I came to the conclusion that these are inferior, last minute, “make
do” constructs. Given the time available to plan, it just makes
sense to do the job properly.
Time and Space
I am constantly amused at how little time people think that they will
be spending in a fallout shelter. Somehow, they seem to equate a nuclear
incident with that of a passing thunder storm/tornado. The problem
is that while a storm does its thing and moves on (or dies out), a
nuclear event has two components: The Blast and the Fallout. What most
folks do not realize is that it’s the Fallout that is “the
gift which keeps on giving” (gamma radiation). And, in most cases,
people will need to create Fallout Shelters to protect and shield themselves
from the gamma radiation contained in the Fallout. Those who live in
target rich areas should consider building a Blast Shelter.
Figuring on a minimum of two weeks (but more likely a month) in the
shelter to allow the radiation to taper off, leads one to consider
not only
providing for clean Air, Food, Water, Clothing, Beds; but also Sanitation,
Exercise, Entertainment. Now, add an average family of four people
into the equation and things become more interesting.
I am reminded of the old gag question: "How many college students can
you fit into a telephone booth?"
A 12’x 8’ (and what height?) basement room is not going
to be enough physical space to handle the family and all the other
things they will need for the duration in the shelter. - Douglas in
CT
Dear Jim,
I believe Mr Yankee is unclear on his terminology. Concrete or other
mass won't stop fallout. Air filters stop fallout, which is radionuclide
particles. These generally precipitate out in a few hours/few days.
A good soaking of the surrounding ground with soap solution will
wash them into the soil and lessen the danger of inhalation/contact
(from stirring up the dust). The reason nuclear residue from weapons
is dangerous is because of its high energy. At the same time, that
high level of radiation means it has a short half life. There are
long term risks of cancer and such, but the immediate risk is quite
controllable. An expedient method is to tape windows shut and use
dryer lint between screens as air filters, drawing up from under
a cover. A sprinkler over the intake to create a water curtain will
improve effectiveness. Obviously, HEPA filters are preferred, if
available.
Direct radiation (Which is what I believe he means by "fallout")
is stopped by concrete, compacted Earth or other dense materials such
as lead. Most modern military warheads are efficient enough that exposure
to lethal levels of radiation means one is already within the radius
of overpressure or thermal blast. Obviously, improvised devices are
not so clean, and there is danger near the edges of an explosion where
one can be exposed to dangerous levels. He is correct that food cans
won't stop such radiation. On the other hand, metals will. Lead is
the classic choice, but gold, silver, copper (you might see where that
is going) and even steel are of some effect, as is the mass of the
house and any outside walls--radiation travels in straight lines, and
if the blast is directly overhead, you won't feel a thing. Copper plates
overhead, with a layer of brick or such, plus the outside walls of
the house, a berm, trees, nearby terrain features or intervening buildings
will all absorb some of the radiation front.
I would recommend against storing materials one plans to use so they
can double as shielding. The shielding can absorb neutrons and re-emit
them as ionizing radiation. This is very unhealthy. The copper, lead
or steel used as such needs to be avoided after the fact, especially
on the blast side. It would be a decent gesture not to trade such materials
off to the unsuspecting to get sick and die from.
I agree on over-engineering and then covering with concrete or compacted
Earth. Something mentioned here before that is quite affordable is
a used CONEX box, which is designed to take high weight on the edges
and corners. A fairly simple bracing atop it (Any mechanical engineer
or even a good construction contractor should be able to calculate
what's needed) will support more than enough mass to act as shielding.
This can be planted outside the basement with a drainage bed of gravel
underneath, accessible from inside, and reducing the risk of the house
collapsing atop the shelter. - Michael
Z. Williamson
