PROTECTION OF VITAL RECORDS AGAINST NUCLEAR WEAPONS EFFECTS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP73-00402R000100140019-9
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 30
• Document Creation Date: December 19, 2016
• Document Release Date: July 19, 2006
• Sequence Number: 19
• Content Type: REPORT

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PROTECTION OF VITAL RECORDS
AGAINST NUCLEAR WEAPONS EFFECTS
We have been very much impressed by the assemblage of talent exhibited
by our predecessors throughout this program on the subject of records
management. It should be clear at the outset, and it probably will be,
that we cannot be considered to be experts such as you have been hearing.
However, with your indulgence we will do what is a common practice in
the technical community. That is, we will make simplifying assumptions
on those things about which we know little, in this case records manage-
ment, and quickly get to a more familiar topic, namely protection from
weapons effects.
Although civil defense and vital records protection does not necessarily
mean protection against the effects of nuclear weapons only, we have re-
stricted our comments to such effects. As far as the nuclear effects are
concerned, we mean those accompanying a nuclear bomb explosion and
characterized by an environment of air blast, ground shock, and of thermal
and nuclear radiation. Typical records, as we understand it, range from
standard office correspondence to photographic film, and may include
books, papers, maps, photographs, and other documentary materials.
Our approach will be to discuss protection philosophies which would pre-
vent destruction of such records by the primary effects of nuclear weapons.
As has been said many times in the past, in connection with protective
construction, the state of the art seems to always lag behind the need.
People were talking of the design of structures suitable against high
explosives when they were faced with the 20 kt bomb (such as the one ex-
ploded over Hiroshima); by the time they allowed for the 20 kt bomb, they
were facing the megaton bomb carried by a bomber and today, of course,
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we face the ICBM. Furthermore, when discussing this subject we are
inclined to think in terms of the effects of a single bomb when it appears
that in the late 60's and early 70's it would be possible for the enemy to
have and to use thousands of ICBM's, meaning that each target area
could conceivably receive many hits or near hits. Naturally it would be
impractical to completely prevent obsolescence in protective construction
with such rapidly changing requirements. On the other hand, to reduce
the lag in the state of the art of protective design, we must be more clever
in extrapolating the needs of the future while weighing the desired lifetime
of the structure with economic considerations.
Nuclear Explosion Phenomena
Before we discuss protection and construction criteria, let us digress a
few moments on the weapon itself. It is generally not a pleasant subject,
but appreciating and understanding the bomb is essential to developing
suitable protection barriers.
When a nuclear weapon explodes, the fission products of the chain reaction
and the surrounding air attain temperatures of millions of degrees,
approaching the temperature in the center of the sun, thereby vaporizing
the bomb casing and other weapon parts. The approximate distribution of
total energy accompanying such an explosion is shown in Figure 1. About
50% of the total is'blast energy, and the remainder is in the form of
thermal and nuclear radiation. Expansion of the heated high-pressure
gases creates the roughly spherical and highly luminous mass known as
the fireball and depicted in Figure 2 for an air burst. Some indication of
its peak brightness is afforded by the fact that the fireball from a one
megaton bomb, when observed from 60 miles away, would appear to be
30 times as brilliant as the noon sun.
The fireball expands rapidly and starts to rise. Figure 3 shows the fire-
ball and shock front from an air burst at an early stage of development,
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and Figure 4, depicting a later stage, shows the Mach front pressure
wave as it travels along the ground surface. Within 10 seconds the fire-
ball diameter from a one megaton bomb is about 1- 1/2 miles and is rising
at about 200 mph. The fireball cools with time and within a minute is no
longer visible. Condensation of the residues forms the characteristic
radioactive mushroom cloud which generally remains visible for about an
hour before it is dispersed by the winds. The characteristics of the cloud
at an early stage are shown in Figure 5. The expanding cloud, at a later
stage, is shown in Figure 6. The top of this cloud may rise to a height
of 25 miles. A more dramatic illustration of the appearance of a mush-
room cloud is given by Figure 7.
In a surface burst the intensely hot fireball contacts the ground surface,
vaporizing a large volume of surface material. It has been estimated that
if only 5% of the energy in a one megaton bomb was expended in this way.,
about 20, 000 tons of soil-an amount covering an average city block to a
depth of about 4 feet-would be vaporized and sucked into the fireball.
This material mixes with the fission products, and, on later cooling,
gradually descends to the earth as radioactive particles referred to as
fallout.
With this physical picture of the exploding bomb itself, let us return to the
question of its effects and set the stage for determining what we are attempt-
ing to protect against. As we mentioned earlier, these effects are nuclear
radiation, thermal radiation, air blast, and ground shock.
To appreciate the nuclear radiation effects and the necessary steps for
protection, we must know: (1) the possible effects such radiation may
have on our materials of interest; (2) the expected level of exposure from
a nuclear burst; and (3) the efficiency of various shielding materials.
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The units of nuclear radiation most often used are called roentgens. As an
indication of the amount of radiation associated with a roentgen, doses of
more than 450 roentgens may be expected to kill 50% of those exposed and
a dose upwards of 700 r will cause 100% fatalities. A dose of less than
200 r is not likely to be lethal. As far as records are concerned, such
materials are much less sensitive to radiation exposure than to blast
damage. Tests- verifying this fact were.carried out at the Nevada Test
Site in 1955 by exposing record storage equipment, containing samples of
known physical and chemical composition, at various ranges from ground
zero. Results of these tests support the conclusion that the amount of
protection required for blast provides more than adequate shielding
against nuclear radiation in the absence of human beings or other radiation
sensitive substances.
Unlike the conventional TNT bomb, the nuclear bomb releases an appreci-
able percentage of its energy in the form of thermal radiation, and at a
very rapid rate. Within a millionth of a second a one megaton nuclear
bomb releases 1015 calories of radiant heat (one thousand million million
calories) which is roughly equivalent to the energy in the amount of gaso-
line needed to drive a compact type car 40, 000 times around the world
at the equator. This thermal radiation, similar to that generated by the
sun, except for its shorter duration, is filtered by the air through which
it passes, so that, at ranges of interest, the significant portions which
remain are the types having long wave lengths; in other words, wave
lengths which lie in the visible and infrared regions of the spectrum.
At ranges beyond the fireball the thermal radiation is rapidly depleted,
and its effect is usually confined to the ignition of combustible materials.
The use of incombustible materials in the records storage structure is
usually adequate to cope with the thermal radiation problem. However,
when dense concentrations of combustible materials occur in a given
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locality, and when certain weather conditions prevail, the fires ignited by
the thermal radiation can develop into an all-consuming conflagration
called a fire storm, which generates intense heat and exhausts the local
supply of oxygen. Safeguarding of records under these conditions requires
shielding from the heat; survival of humans would also demand such pro-
tection, and an emergency oxygen supply as well.
The air blast can be loosely described as a traveling wave of compressed
air moving at supersonic speed. Accompanying the main blast wave is the
wind generated by the detonation which can also have supersonic speeds
when the overpressure exceeds about 20 psi. This blast wind generates
what is called dynamic pressure.
The compressed air effect (called overpressure) exerts an inward squeez-
ing or crushing force on the exterior walls of structures, while the dynamic
pressure acts in the familiar manner of high winds in tending to move
exposed objects in the direction of the blast. In passing over the ground
surface, the blast wave exerts a downward pressure on the soil which
causes squeezing forces in the soil acting both vertically and horizontally.
Since the blast force acting on the surface is applied suddenly rather than
gradually, the effect is like that of a giant blow, creating ground vibrations
similar to those of an earthquake but often much more violent. These
forces are often called "ground shock, and require measures similar to
those used in designing against earthquakes. In the case of records
storage, these forces may require anchorage of the record containers to
prevent sliding and overturning.
Relative Effects on Exposed and Buried Structures
Figure 8 compares the relative importance of certain considerations as
they apply to structures located on the ground surface and to those which
are buried. It is apparent that, compared to the buried structure, the
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surface structure receives much higher blast pressures, is afflicted with
problems of sliding and overturning from blast wind, is exposed to damage
from flying debris, and is at a disadvantage from the standpoint of radiation
shielding. As shown in Figure 9, advantages of the surface structure are
those related to normal operating conditions rather than blast conditions,
such as ease of access and fewer problems with ground water and venti-
lation. These considerations largely account for the fact that failures of
buried structures under nuclear blast are much less common than failures
of structures located above ground and are usually confined to surface
features such as entrances, and intake and exhaust ducts. The presence
of earth cover is a bonus in providing the least expensive form of shield-
ing from both nuclear and thermal radiation. It should be noted that,
under certain conditions, a structure located on the ground surface can
receive the advantages of complete burial through the use of a properly
designed earth mound encasing the structure.
Examples of Blast Damage
The following series of illustrations is presented to give some indication
of the damage potential of a nuclear blast. Figure 10 shows a three-
quarter view of a multistory camera bunker located at the Eniwetok
Proving Ground. This structure is similar to another bunker (Ref. 4)
shown in detail in Figure 11. The bunker of Figure 11 received severe
damage from a nuclear detonation in the multi-megaton range which
created blast pressures far greater than the anticipated value. The
damage consisted of failure at the sill of the heavy steel blast door
located at the front of the bunker, as postulated in the series of events
shown in Figure 12, the door finally being wedged in the vertical shaft at
the rear of the structure. One beneficial result of this incident is the
subsequent series of laboratory tests initiated by Holmes &Narver at
Massachusetts Institute of Technology, aimed at reducing the uncertainties
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inherent in estimating the strength of concrete under stress conditions
similar to those which existed in the door sill. (Refs. 5, 6, and 7).
Figure 13 is a post shot view of the damage. The zone surrounding the
door opening is severely pitted with impact craters, suggesting that this
area could have been sprayed with a jet of flying debris. Further evidence
of airborne particles is shown by the rounded appearance of edges and
corners as if by sandblasting.
The abandoned structure was in the path of an additional shot which caused
further extensive damage as shown in Figure 14. An interesting feature
here is the peeling away of a large portion of the reinforcing steel in the
sidewall of the bunker. The bars have the appearance of strings of
spaghetti and the imprint of the bar grid pattern is still visible in the con-
crete surface. A further view of the damage is shown in Figure 15.
A structure of special interest from the standpoint of record protection,
because it simulates a conventional bank vault, is shown in Figure 16.
This vault was involved in a test sponsored by the Federal Civil Defense
Administration in Operation Plumbbob at the Nevada Test Site (Ref. 8).
The vault door, facing the blast, was subjected to a dynamic pressure
of several hundred psi. The principal result, shown in Figure 17, was
severe damage to the reinforced concrete sidewalls of the structure,
involving the peeling away of the reinforcing bars already discussed
in connection with the camera bunker. It is evident that while grids of
reinforcing bars are essential to the integrity of reinforced concrete
construction, they do constitute planes of weakness, and under certain
conditions of exposure special measures are needed at critical points
in such construction to prevent damage. However, in this case the
steel plate lining encased in the concrete remained intact. The door
itself was structurally undamaged and was opened with no difficulty.
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Figure 18 shows the grand opening.
These case histories do not necessarily imply that the design of blast-
resistant, completely exposed surface-mounted structures is a futile
effort. The experience of our firm in having designed and built a major
portion of the blast resistant construction actually subjected to nuclear
detonations in both the kiloton and megaton ranges (Ref. 4) indicates that
certain types of surface structures can be built to survive hundreds of
psi. However, there is a lesser degree of confidence in such structures
than in similar earth-covered structures because they are much more
vulnerable to unpredictable variations in the nature of the blast wave.
Progressing to still smaller structures, a series of record containers of
varying sizes and strengths was tested by the research staff of the
National Records Management Council and cooperating agencies in
Operation Teapot at the Nevada Test Site (Ref. 9). These consisted of
safes and file safes, (Classes A, B, and C), and insulated and uninsulated
file cabinets. These containers, completely exposed to the blast, and
containing microfilm, correspondence, telegraphic tape and similar items,
were located at pressure levels of about 8 to 50 psi. Figure 19 shows a
pre shot view of a portion of this equipment at the 50 psi range. File
cabinets, transfer files, steel shelving, and similar equipment with
similar contents were located within structures at pressure ranges of
roughly 2 to 8 psi.
Nuclear radiation damage to the contents was nil, except for some slight
effect on purified sulfite paper. In general, blast damage to the com-
pletely exposed containers was total at ranges in excess of about 18 psi,
as shown in Figure 20. Figure 21 is a pre shot view of a Class C safe
at the 19 psi range, and Figure 22 is a postshot view of the remains,
560 feet from the original position. The containers housed within
structures were essentially undamaged.
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Approaches to Protective Design
Let us now consider, philosophically at least, some approaches to actual
protective design. In the attempt to beat the bomb, two general courses
of action can be considered: dispersal, which relies on remoteness from
potential ground zero locations; and hardening, which relies on built-in
protection against the various bomb effects (air blast, ground shock,
radiation, etc. ).
An example of the dispersal approach is the vital records center recently
constructed at a location about 50 airline miles from the Vandenberg
Air Force Base, and shown in Figure 23. This is not a large structure;
the floor area is approximately 24 feet by 41 feet. The facility is com-
pletely "soft" in its resistance to blast effects except for the above
average radiation resistance provided by the windowless reinforced con-
crete walls and reinforced concrete roof, which also afford a dustproof
and fireproof internal environment.
Under normal day-to-day operating conditions the ventilating air is
filtered, and a slight positive interior pressure is maintained to prevent
dust accumulation. Should fallout conditions lead to a radiation intensity
exceeding a predetermined level, the ventilation system is shut down
through the action of sensing devices mounted on the roof.
The hardening philosophy can be exemplified by the group shelter shown
in exterior view in Figure 24. It should be emphasized that, although this
is not a vital records center, it is readily adaptable to such a function.
The structure consists of a Multiplate corrugated semi-circular steel
arch of the type commonly used by the Navy for ammunition storage, and
similar in many respects to the type of structure often used for highway
culverts (Ref. 10). The arch covers a reinforced concrete floor slab
25 feet by 48 feet. A mechanical utility room is located at one end in a
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corrugated steel pipe, and a similar pipe sloping upward provides an
access to the entrance at the surface. A cutaway view of the interior is
shown in Figure 25. Principal features include: (1) minimal accommo-
dations for 100 people for a period of two to four weeks; (2) a blast
resistance of at least 35 psi; (3) a reduction in radiation from fallout by a
factor of about 1/10, 000 of the intensity on the surface; and (4) complete
sealup without outside air for 3 hours, and maximum button-up (using
outside air) for one week.
Required Levels of Protection
How much protection should be provided? One important consideration in
this regard is the location with respect to military or population-industry
targets. In the heart of target cities, resistance is needed against: (1) air
blast; (2) ground shock; (3) flooding due to ruptured water mains (or blast
generated water waves if the weapon is detonated near the surface of an
adjacent body of water); (4) thermal effects including heat from burning
structures; and (5) flying debris. In the case of records centers in the
basements of buildings, debris protection includes safeguarding against
the consequences of collapse of the entire building above as well as protection
from.the debris of adjacent structures. Only a nominal degree of radiation
shielding is necessary unless items such as transistors and photographic
and X-ray supplies are being stored.
In rural areas say in locations exceeding about 25 miles from major
target areas required protection is minimal. However, incombustible
construction is desirable in the storage structure because of the long
range thermal effects of large yield weapons.
Another important factor in establishing the amount of protection to be
provided is the extent to which safety of personnel is to be considered.
At close-in distances, the requirements for safeguarding of personnel
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become very stringent compared to those for records protection, pri-
marily because of the need for such additional requirements as ventilation,
water, food, sanitation, light, radiation shielding, monitoring, and
decontamination facilities, etc. In the heart of target cities adequate
personnel protection may demand shielding against all effects associated
with a pressure level of 100 psi or more.
Hardened Vital Record Storage Concepts
Generally, in the heart of target cities, the only suitable place for records
storage is to be found in locations below ground level, such as in base-
ments. A schematic cross-sectional view of a hypothetical vault
appropriate to this environment is indicated in Figure 26. The box shape
is dictated by the available space. Such construction can become ex-
tremely massive and correspondingly expensive and is especially costly
when installed in existing buildings. The vault shown features a com-
pressible layer of material on the roof to absorb the impact occasioned
by possible collapse of the floors above.
In some instances when the volume of record storage is small, and where
some inconvenience in access is acceptable, small containment structures
can be used, located flush with the floor surface or mounted flush with the
surface of an exterior wall. For maximum hardness, the structure should
be circular in section rather than rectangular, and can consist of concrete
pipe or corrugated steel pipe. Such structures can be made resistant to
hundreds of psi (Ref. 11 and 12). This approach is illustrated in concept
in Figure 27 which shows a longitudinal section thr ough a floor-mounted
structure of this type, utilizing corrugated metal pipe. Figure 28 shows
a horizontal version of the same thing, using reinforced concrete pipe.
This horizontal configuration gives more convenient access and may be
desirable where lack of property-line restrictions and other interferences
permits its use.
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If sufficient yard space is available, larger structures below ground
become feasible, the restrictions imposed by the cramped basement
quarters are avoided, and there is more freedom to choose efficient
structural forms. In many cases the presence of the underground struc-
ture imposes no significant restriction on the normal use of the yard
space above. Figure 29 shows in concept a cutaway perspective view of
a buried arch-type structure of this nature. The material can be either
reinforced concrete or steel. Maximum strength per unit of structural
material is obtained using a dome shape, shown conceptually in Figure 30.
In this case, the construction material is reinforced concrete.
Protective construction is seldom cheap, and costs mount as hardening
requirements increase. It is impossible to give anything but a gross indi-
cation of such costs. More accurate estimates require a preliminary
design for specific conditions, and several such designs would be needed
to arrive at minimum costs for any given facility. Very approximately,
the cost of a conventional "soft" structure, located on the ground surface,
with reinforced concrete walls and roof, may lie in the range of $8 to $12
per square foot of floor area, based on the structure alone, excluding
mechanical, electrical, and sanitary facilities. Hardening such a struc-
ture to 100 psi may more than triple these costs because of the need for
thicker walls, earth cover, and a special entrance structure. A hardened
arch-type structure can be economical, under certain conditions, and a
hardened dome type enclosure may be optimum when built in sizes large
enough to permit the use of more than one floor level.
Heating, ventilating, and air conditioning can add $5 to $8 per square foot,
and electrical features $4 to $6 per square foot. Water supply and sanitary
features can be as much as $300 per person. These features would be
necessary if personnel protection is to be considered.
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No generalization as to costs is possible when protective construction
involves locating storage facilities in existing buildings, except to state
that these more restrictive conditions would probably cause an increase
in construction expense.
Concluding Remarks
In the short time available, it has not been possible to cover in adequate
detail the various aspects of protective construction relating to records
storage facilities. However, if recent events impel an active interest in
protective construction, it is our hope that what we have presented can
serve as a useful guideline in the planning and execution of such progr'b.ms.
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1. Samuel Glasstone, Editor, The Effects of Nuclear Weapons, prepared
by the U. S. Department of Defense for the U. S. Atomic Energy
Commission, June 1957.
2. H. L. Brode, (Rand Corporation), Weapons Effects for Protective
Design, March 1960.
3. F. E. Anderson, Jr., R. J. Hansen, H. L. Murphy, N. M. Newmark,
M. P. White, Design of Structures to Resist Nuclear Weapons Effects-
Manual of Engineering Practice - No. 42, American Society of Civil
Engineers, 33 West 39th Street, New York, N. Y. , 1961.
*4. R. A. Williamson, (Holmes & Narver, Inc.), Performance and Design
of Special Purpose Blast Resistant Structures, Journal of the American
Concrete Institute, May 19 0.
5. R. J. Hansen, E. G. Nawy, J. M. Shah, Response of Concrete Shear
Keys to Dynamic Loading, Journal of the American Concrete Institute,
May 196-1--.
6. E. G. Nawy, J. M. Shah, The Response of Concrete Shear Keys to
Dynamic Loading, Report for U. S. Atomic Energy Commission, under
Contract No. AT (29-2)-616, Massachusetts Institute of Technology,
Department of Civil and Sanitary Engineering, Structural Division,
January 1959.
7. A. A. Liepins, Behavior of Bond Under Dynamic Loading, Report for
U. S. Atomic Energy Commission under Contract No. AT (29-2)616,
Massachusetts Institute of Technology, Department of Civil and
Sanitary Engineering, Structural Division, September 1959.
8. E. Cohen and E. Laing, (Ammann and Whitney), Response of Protective
Vaults to Blast Loading, Report ITR- 1451, Nov. 22, 1957, Civil
Effects Test Group, Operation Plumbbob, Nevada Test Site. Avail-
able from Office of Technical Services, Department of Commerce,
Washington 25, D. C.
9. Research Staff, National Records Management Council, Inc. , Effects
of a Nuclear Explosion on Records and Records Storage Equipment,
Report WT-1191, June 18, 1958, Civil Effects Test Group, Operation
Teapot, Nevada Test Site. Available from Office of Technical Services,
Department of Commerce, Washington 25, D. C. (Price $1. 25).
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10. AEC Facilities Division, Holmes & Narver, Inc., AEC Group
Shelter, Report CEX-58. 7, June 22, 1960. Civil Effects Test
Operations, U. S. Atomic Energy Commission. Available from
Office of Technical Services, Department of Commerce, Washington
25, D. C. - (Price $0. 50).
11. R. A. Williamson and P. H. Huff,(Holmes & Narver, Inc.), Test of
Buried Multiplate Pipe Subjected to Blast Loading, Report WT- 1474,
July 28, 1961, Civil Effects Test Group, Operation Plumbbob,
Nevada Test Site. Available from Office of Technical Services,
Department of Commerce, Washington 25, D. C. - (Price $1. 25).
R. A. Williamson, Blast Damage to Structures Tested In Operation
Plumbbob, paper presented before the American Society of Civil
Engineers, Los Angeles Section, Structural Group, Nov. 12, 1958.
D. L. Narver, Jr. , (Holmes & Narver, Inc. ), Nuclear Blast Design.
14. D. T. Robbins and R. A. Williamson, (Holmes & Narver, Inc. ),
Analysis Report for Basic Types of Underground Structures, for
the Waterways Experiment Station, Corps of Engineers, U. S. Army,
Vicksburg, Mississippi, October 1956, (Secret Restricted Data).
15. D. T. Robbins and R. A. Williamson, Post-Shot Analysis for
Project 3. 1 - Operation Plumbbob for the Waterways Experiment
Station, Corps of Engineers, U. S. Army, Vicksburg, Mississippi,
April 1958 (Confidential).
16. R. A. Cameron, R. A. Williamson, R. H. F. Boothe, (Holmes &
Narver, Inc. ), Evaluation of Nuclear Blast Effects on AEC Test
Site Facilities, Report WT-1455, Civil Effects Test Group,
Operation Plumbbob, Nevada Test Site, (Publication Pending).
17. Herman Kahn, (Princeton University), Why Go Deep Underground?
Proceedings of the Second Protective Construction Symposium
(Deep Underground Construction), held at the Rand Corporation,
Santa Monica, California, March 23, 24, 25, 1959, R- 341,
Volume I, Compiled by J. J. O'Sullivan.
*Reprints available on request from Holmes & Narver, Inc. , 828 South
Figueroa Street, Los Angeles 17, California.
15
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