239 lines
16 KiB
Plaintext
239 lines
16 KiB
Plaintext
This file may be downloaded as INJURIES.ZIP
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This report concerns the types of injuries that will be produced by a
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nuclear explosion. The first topic to be covered will be scales of
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destruction, or how different sizes of bombs will produce different mixes of
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injuries and at what ranges. This part has a little math and geometry in it
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but is only five minutes long. Don't go to sleep yet! The second topic will be
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types and ranges of injuries caused by the blast portion of the bomb. This will
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cover injuries caused strictly by the over-pressure, throwing the body from the
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static pressure, injuries from hurled objects, and injuries from collapsing
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buildings. The third topic will cover immediate burns caused by the heat from
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the bomb itself and secondary burns from items ignited by the bomb. The
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fourth topic is ionizing radiation, prompt (immediate) and secondary (fallout).
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Many films that you see about the effects of nuclear weapons are based on
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the experiance gained from Hiroshima and Nagasaki. Some people say that there
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is nothing to be learned from there since today the weapons are hundreds and
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thousands of times more powerful. Those films can be informative IF you
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understand that a bomb is a sherical phenomenon. People are used to thinking
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linearly 1+1=2, 2+2=4, etc. But spheres aren't like that. Let's look at some
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math for a bit here.
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One dimension. All this is, is addition, 1+1=2, 2+2=4, 4+4=8, 8+8=16, etc.
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If we want to increase the distance that we can reach with a stick all we
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have to do is increase the length of the stick by the same factor - in other
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words to double the distance/reach you just double length, triple the distance/
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reach, triple the length, ten times the distance/reach, ten times the length.
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That's simple, everybody understands that! However...
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Two demensions, now we are talking of area, this is multiplication now!
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1x1=1, 2x2=4, 4x4=16, 8x8=64, 64x64=4,096, etc. The term "SQUARED" is used,
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which is just a number multiplied by itself. 2 squared = 4, 4 squared = 16,
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8 squared = 64, 64 squared is 4,096, etc. Think of this as pouring a bucket of
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paint over a flat floor and figuring out how many cans of paint we need to
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cover a larger circle than just a single can would cover.
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If we want to increase the size of a circle that we are going to paint we
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have to use the formula of a circle's area which is Area = Pi times radius
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times radius or A = Pi x R x R or A = 3.1416 x R-squared. Here if we have a
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circle of one unit of radius (foot, meter, yard, whatever) we need "X" amount
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of paint to cover that area 3.1416 x 1 x 1 = "X". If our circle's radius
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increases by a factor of 2 we need 4 times "X" amount of paint, 3.1416 x 2 x 2
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= 4"X", for three times the radius we need 9 times "X" amount of paint,
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3.1416 x 3 x 3 = 9"X". For ten times the radius, 100 "X" amount of paint,
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3.14.16 x 10 x 10 = 100"X". That's a little more difficult.
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Three dimensions! Here's where we lose people. If you are sleep prone,
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I'll try to wake you after I talk about the math a bit. We are still using
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multiplication, just more of it! To figure out the Volume of a box we
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multiply Height times Width times Depth, or V = H x W x D. For
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calculating the volume of a shpere we take four divided three times Pi times
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radius times radius times radius, or Volume = 4/3 x Pi x R x R x R, or
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V = 1.3333 x 3.1416 x R x R x R, or V = 4.1888888 times R cubed. Cubed is
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just a number multiplied by itself twice. 1 cubed = 1x1x1 = 1, 2 cubed = 2x2x2
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=8, 3 cubed = 3x3x3 = 9, 4 cubed = 4x4x4 = 64, 10 cubed = 10x10x10 = 1,000
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Now that we know all of that!!! the rest is easy....
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A standard rule of thumb for recalculating blast effects for various sizes of
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bombs is to take the megatonage of the new bomb divide by the megatonage of
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the old bomb, take the cube root of the results and multiply that times the
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radius of blast effect. Example to compare a 1 KT (0.001 MT) to a 1,000 KT
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(1MT) 1,000 divided by 1 = 1,000. The cube root of 1,000 is 10
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(10x10x10=1,000). Therefore you can take the blast effect at X feet (or miles)
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for a 1 KT and multiply that distance by 10 to get approx. the same effect for
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a 1,000 KT bomb. Other common multipliers would be
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Mulitplier/divider cube/cube root 1 KT multiplier 1 MT divider
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2 2x2x2=8 8 KT 125 KT (0.125MT)
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3 3x3x3=27 27 KT 37 KT
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4 4x4x4=64 64 KT 16 KT
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5 5x5x5=125 125 KT 8 KT
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6 6x6x6=216 216 KT 4 KT
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7 7x7x7=343 343 KT 3 KT
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8 8x8x8=512 512 KT 2 KT
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9 9x9x9=729 729 KT 1 1/3 KT
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10 10x10x10=1,000 1,000 KT (1 MT) 1 KT
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So this shows that if you want to double the damage distance for a given size
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of bomb you need to increase the power by a factor of 8. If you want to double
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that distance again you need a bomb that is 8x8 or 64 times as powerful. This
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is why you can get the same amount of damage done with 10-40 KT bombs spread
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out as you can with a 1,000 KT (1 MT) bomb. So if we look at Hiroshima with
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20KT and say okay what will a 1MT (1,000KT) bomb do? Well 1,000/20 = 50. Now
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then, what times what times what = 50, well 3.7 cubed is 50.653 so an effect
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one mile from GZ at Hiroshima will be the same effect at 3.7 miles for a 1MT.
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Now this is for blast effects not heat effects, we'll cover those later.
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Okay any questions?
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All right, that's the end of the math, you can wake up again!
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Okay let's talk about blast injuries. To avoid confusion we need to talk
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about overpressure (static-pressure) and dynamic pressure. When you think
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about overpressure, think about a barometer, normal air pressure is about
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15 P.S.I. Overpressure is simply the air pressure in excess of the normal
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atmospheric pressure. Overpressure is what would cause an empty sealed can to
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be crushed on all sides. Dynamic pressure is a wind. Dynamic pressure is the
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figure that we use to calculate the horsepower of a sail on a sailboat. Damage
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is caused by wind resistance. The dynamic pressure is proportional to the
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square of the wind speed and to the density of the air behind the shock front.
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In a nuclear blast the air density can be quite high and this is why just
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looking at the wind speed alone doesn't give the entire story. Also, the
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duration of the dynamic pressure comes into effect. Dynamic pressure is what
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would cause an empty sealed can to be blown into the next county. Think about
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a sheet of plywood placed perpendicular or parallel to a blast front. Ignoring
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the time it takes for the overpressure to get from the front to the back of
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the plywood, the overpressure shouldn't do much damage. Contrast that to the
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same sheet hit broadsides or sideways by dynamic pressure!
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A further note on duration. Many things can take great stresses over very
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short periods of time. Example, a fast blow fuse can pass ten times its
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amperage rating for a fraction of a second. In overpressure this is why lung
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injuries occur at pressures that would not cause harm if the pressure were for
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only a second or two.
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Ok, injuries in humans caused by the blast. Now when I talk about injuries
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from a specific effect I am talking about just that single effect. In real
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life, a victim might have some lung damage, some broken bones, 2nd degree
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burns, and some blood loss from flying glass shards. Each one seperately might
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not be lethal, but in combination they might be.
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Let's start with overpressure. Overpressure is associated with ear and lung
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damage from fast-rising, long duration pressure pulses. If it were a slow
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rising pulse the body can equalize, as in scuba-diving. If it were short
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duration the parts could stand greater stress. You won't die from eardrum
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rupture, but it does reduce your abiltiies! 5 Pounds per Square Inch is where
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eardrum rupture starts. There is a great deal of variation in suscetabilty to
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damage. The very old are most susceptable. 50% of population rupture occurs
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at around 15-20 PSI for over 20 years old and around 30-35 PSI for under 20
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years old. Again, there is a wide individual variance here. Also, some
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eardrum will spontaneously heal with only slight or partial hearing loss.
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Lung damage begins at 12 (8-15) PSI. Severe lung damage occurs at 25 (20-30)
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PSI. Lethality begins at 40 (30-50) PSI, 50% lethal at 62 (50-75) PSI and
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100% lethal 92 (75-115) PSI. P.549 "Persons who spontaneously survive for 24
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to 48 hours in the absence of treatment, complications, or other injury usually
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recover and show little remaining lung hemmorrhage after 7 to 10 days. In very
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severe injuries under treatment, recurring lung hemorrhage has been reported as
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long as 5 to 10 days after injury.
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Overpressure 20KT 200KT 2MT 20MT
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1 PSI 3.5 miles 7.5 miles 16.5 miles 36 miles
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2 PSI 2.1 4.6 10 21
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5 PSI 1.1 2.5 5.4 12
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40 PSI .28 .6 1.3 2.8
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62 PSI .23 .5 1 2.3
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92 PSI .19 .4 .9 1.9
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Any questions on overpressure?
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Dynamic pressure injuries are typically measured in the speed (feet/second)
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at which a human body is thrown against something hard. Injuries here are
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cuncussion, skull, heel, foot, legs, and arm fractures. There is a great deal
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of variability in these injuries. A threshold of injuries standing up might
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occur at 10-12 ft/sec with fractures at 13-16 and while sitting the threshold
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may be 15-26 ft/sec. Skull fractures - "safe" 10 ft/sec, threshold 13, 50% at
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18 ft/sec and 100% at 23. From total body impact - mostly "safe" 10 ft/sec.,
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1% fatal 21 ft/sec, 50% 54 ft/sec., and near 100% 138 ft/sec. These are
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assuming that the body is hurled perpendicular against a hard object.
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Dynamic pressure 20KT 200KT 2MT 20MT
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10 ft/sec 1.2 miles 3.0 miles 7.4 miles 17 miles
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21 ft/sec .9 2.4 6 14
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54 ft/sec .6 1.7 4 9.5
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138 ft/sec .3 .9 2.4 5.5
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Well what about being blasted in an open field? You can be tumbled to death.
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There are no good figures on this since there is no actual data and only
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animal experiments have been used. The best guess is that 1% non-fatal injury
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would occur at 30 ft/sec. and 50% injured at 75 ft/sec. We really don't know.
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Any questions on dynamic pressure?
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Many casualties and deaths will occur from building collaspe. A typical
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house is calculated to have these characteristics. 50 PSI = 100% certian dead,
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20 PSI = 50% killed - 35% trapped - 5% untrapped but seriously injured, 10 PSI
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= 10% killed - 35% trapped - 6% untrapped but seriously injured. 5 PSI = 1%
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killed - 10% trapped - 6% untrapped but seriously injured. Now those are from
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the British home office and for overpressure ONLY. I feel they are whistling
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in the dark, but perhaps they figure that a British house has stronger and
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heavier sidewalls if it uses structural brick or stone rather than using
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brick as a decorative siding as in America.
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Injuries from heat can be burns from the flash or secondary fires. Flash
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burns and fires are HIGHLY variable due to landscape interference, dust and
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moisture in the air, and topography. While there is some damage from
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reflected light and heat, most of the damage is from line of sight to the
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point of explosion. Another complicating factor in heat related injuries is
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the speed at which the bomb releases its heat and how well the object or person
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relfects, absorbs or disipates the heat. Smaller bombs dump their heat
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quicker since there is less heat to dump. See chart.
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Percentage of
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heat released 20 KT 200 KT 2 MT 20 MT
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20% .16 seconds .4 seconds 1.15 seconds 3 seconds
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50% .35 .95 2.2 7
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70% .8 2.2 6 15
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Whites reflect heat while blacks, blues, and purples absorb heat. Also, even
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though the object is stationary and doesn't move (by say failing to the ground
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and rolling) it can still release heat while more is coming in. That is why
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just looking at the calories per square centimeter at a certian distance does
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not tell the whole story. Examples, see P. 564 and P. 565. A third degree burn
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from a 10 MT ranges from 10.5 to 12.5 Calories per Square Centimeter depending
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on skin color and a 3rd degree from a 20 KT ranges from 6 to 8 Cal/SqCm. For
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those two bomb sizes 2nd degree burns range from 6.5 to 8.25 and 4 to 5 CSC.
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For 1st degree burns 3.5 to 4.5 and 2 to 2.5 CSC for 10MT and 20 KT. With the
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range of needed CSC linear for bombs in between those two sizes.
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Degree of burn 20KT 200 KT 2 MT 20 MT
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First 2.2 miles 6.2 miles 16 miles 35 miles
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Second 1.7 4.8 12.5 30
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Third 1.3 3.8 10.5 26.5
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SIZE 35 KT 1.4 MT 20 MT
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Paper bag burns 10 Cal/SqCm 13 Cal/SqCm 20 CSC
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New blue jeans burn 12 27 44
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white cotton shirt burns 32 48 85
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Here is what range you would get from various bombs
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Cal/SqCm 20 KT 200 KT 2 MT 20 MT
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1 3.4 miles 9 miles 22 miles
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5 1.7 5 13 35
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10 1.2 3.6 10.5 29
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20 .85 2.6 8 23
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50 .55 1.7 5.4 17
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100 .4 1.2 4 13
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Please remember these are assuming a clear sky, no rain, no dust, no haze,
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no smog, etc.
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Injuries to eyes fall into two catagories. Permanent (retnal burns) and
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temporary flashblindness. You of course can suffer from both. Flashblindness
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is just like staring into a flashbulb, useful vision is lost for several
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seconds to several minutes. A retnal burn causes blindness on the point of
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the retina where the flash is seen. There is an emense variation here
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depending again on clarity of sky and also whether the pupil is wide open at
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night or fairly closed from mid-day sun. See page 571-574 for details.
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There is one other eye "problem" that should be mentioned, Keratitis which is
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inflamation of the cornea. The symptoms are pain caused by light, a sensation
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that a foreign body is in the eye, lachrymation (unnatural tears), and redness.
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These symptoms lasted from a few hours to several days. At Hiroshima only 4%
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of those standing in the open within 1.25 miles of GZ suffered keratitis within
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24 hours. An additional 1.5% had symptoms up to one month.
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Wake up! I'm almost done.
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The last and FINAL topic is radiation. Immediate radiation from the the
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blast is significant only from smaller bombs since the deadly other effects
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outdistance the radiation effects in larger bombs.
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REMS 20 KT 200 KT 2 MT 20 MT
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1 1.7 miles 2.1 miles 2.8 miles 4 miles
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10 1.4 1.8 2.4 3.6
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100 1.05 1.45 2.1 3.2
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400 .9 1.3 1.8 3
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1,000 .8 1.15 1.7 2.8
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10,000 .54 .85 1.3 2.3
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100,000 .32 .56 1.8 1.68
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1,000,000 .16 .33 .59 .97
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The reason that 10,000 REMS and higher is included in this chart is that it
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is possible to build shelters to withstand 200 PSI overpressure. These
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are usually buried enough to have Protection Factors of over 1 million. See
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FIGHTING CHANCE: 10 feet to Survival and FIGHTING CHANCE newsletter.
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Strike Any Key To Continue
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