CA1278972C - Temporary/portable nuclear fallout shelter - Google Patents

Abstract

ABSTRACT OF THE IVENTION
Significant, life-saving protection from airborne, radio-active (fallout) particles due to nuclear explosions, nuclear reactor accidents, and other releases of radioactive particulate is provided by a double-wall tent structure quickly erectable over a central trench hole. The tent structure includes tight-ly woven, rip-resistant fabric panels supported by tensile rods or wands, a tub floor extending into and lining a central trench or hole, and an exterior, light-reflecting, metalized, semi-transparent disposable membrane. The bottom circumferential edge of the outer membrane extends into a shallow trench or-ditch, excavated around the perimeter of the inner tent structure. Dust particles settling onto the smooth exterior surface of the mem-brane slide off and are captured in the shallow ditch, thus minimizing direct or indirect radiation into the central trench or hole and its occupants. The perimeter of the outer membrane contains pockets for the storage of potable water and for anchor-ing of the outer membrane. The tub floor lining extending below the ground surface includes sealable pockets suitable for the storage of refuse and human waste during occupancy. Also de-scribed is a light-weight single membrane, plastic, portable tent, suitable for low-cost mass production.

Description

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1 sAc~G~o~ND OF ~ INVENTIOR

2 Sheltecs for protecting individuals from residual nuclear 3 radiation emanating from radioactive airborne particles (fallout) are typically designed for the purpose of attenuating high-energy gamma radiation. In particular, conventional fallout shelters 6 are usually designed as permanent underground structures to pro-vide shielding and are constructed of high density materials to 8 attenuate radiation emanating from radioactive fallout on the 9 ground and on top of the shelter. Such structures are immovable, expensive to construct, and difficult to maintain.
11 Permanent fallout shelters also have distinct disadvant-12 ages in that they can become traps for their occupants in the 13 event of blast or fire of the ~tructure abave them. Occupants 14 can also be trapped by their shelters in areas of high-intensity fallout simply because they do not have suitable shelters avail-~ 16 able to them elsewhere. ~inally, after a period of time, perma-i~ 17 nent shelters can become contaminated by radioactive contami-18 nants, carried by inadvertent human traffic in and out of the shelter, and thu~ become unusable.
Also, most of the world's population does not live ~n 21 anticipated prime target areas in the event of nuclear war, but 22 does llve in areas conceivably affected by radioactive fallout 23 from nuclear explosions in the target areas.

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8~2 1~ Moreover, large numbers of people live in areas that can 2 be significantly affected by radioactive contamination from acci-3 dents involving nuclear reactors. Construction and maintenance 4 of permanent fallout shelters composed of high-density materials, protecting populations in areas downwind from a nuclear reactor, 6 has not been considered practical. The effectiveness of large-7 scale evac~ations of populations downwind of nuclear accidents is 8 also in doubt due to panic, loss of effective communications, 9 and abandonment of traffic controls.
Further, case studies of World War II disasters show that 11 in general, civilian populations tend to return to the homes 12 once abandoned, expecting to find shelter and life substance. In 13 summary, a need exists for a portable lightweight, low-cost 14 shelter to provide protection from radioactive airborne dust particles.
16 It is generally known that a simple hole in the ground 17 can provide significant protection fom gamma radiations emanating 18 fro~ surface contaminants. In particular, an individual who 19 positions him~elf in the hole i~ effectively shielded by the surrounding earth from radiation~ from surface particles. Fur-21 thermore, the effective protection provided by a hole in the 22 ground i~ significantly enhanced if the contaminants can be 23 prevented from settling into the hole, above the hole, or adia-24 cent to the wall~ of the hole. See ç~b-~iyi~ f~ rQs~m ~l~nnl~a~-vQl~e 1, A~p~n~i8-E~ Page 1-7 (1964), Re~earch Trian-2~ gle Institute.

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1~ It is also generally known that the intensity of radioac-¦
2¦ tivity fro~ nuclear weapon fallout decreases relatively quickly.¦
31 The intensity falls by a factor of lO after 7 hours, a factor of¦
41 lO0 after 49 hours, and a factor of lO00 after two weeks. A dose above 50 rem over a short perid of time (6 to 7 days) in 90% of 6 the cases is fatal to the person exposed, with death occurring 7 within a few weeks. Death may result from the effects of radia-8 tion or from opportunistic, commonly known infectious agents. tA¦
9 rem or ~roetgen-equivalent-man~ is a measure of biological damage.) 11 Populations living largely downwind of targets and out-12 side the central zone directly affected by blast and thermal 13 radiation are expected to receive from 900-3000 remv Such popu-14 lations will die or be severely injured unless they can be pro-tected from the effect~ of short-lived radioactive debris and 16 fallout. Since the estimated maximum toleratable dose is 25 rem, 17 (cumulative) large fraction8 of such population8 can be saved by 18 trenches and/or holes which provide a protection factor of lO0 or 19 better~ provided that the accumulation of radioactive fallout 2~ in8ide the trench can be prevented. ~It is of interest to men-21 tlon that a 8imple one-man foxhole,3 feet in diameter and 4 feet 22 deep, can provide a protection factor of about 40 if fallout is 23 pre8ent up to the edge, but not inside. If an area of ~-4 feet 24 wide around the foxhole is kept free of fallout material, a protection factor of lO0 or more is possible.~ ff~ Qf 2~ ~ w~QD~r Samuel Glasstone, Revised ~dition, 1964, page ' . - .

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~¦¦ 473~ section 0.140.
2 ¦¦ Radioactive fallout from a nuclear reactor is generally 3 ¦¦ known to be long-lived. He~e, the immediate protection of the 4l population from intensive radiation, inhalation, and ingestion of 5l radioactive particular matter is of paramount importance until 6¦ rescue missions can be executed. Under peacetime conditions, 7 rescue can be expected to take place shortly after an accident.
8 Even in instances where a nuclear weapon explosion causes a~
9 nuclear reactor accident (the worse case possible), if the affec-ted population has 30 to 60 minutes' warning and can take shelter 11 in some sort of portable/temporary fallout shelter, the magnitude 12l of injury can be significantly reduced.
13 Other references which discuss problems of shelter for 14 populations in the event of significant radioactive particulate 15 fallout include: ;
16 ~iQn~l-E~llQ~ h~ L-pLQgL~m~ Sixteenth Report by the Committtee on Government Operations, May 32, 19~2, 87th 17 Congress, 2nd Session, ~ouse Report No. 1754.
18 ~in~ e-Q~_~iYi~ f ~n~ L~ h~ .S.R., by 19 Yu Yu Nammerer et al., July 1967.
Refer to Publications of the Department of the Navy, ~ureau of Yards and Docks.
21 E~11Q~t_~-O~C~iQ~Q~Qm~ m~ , Revised, May 22 1967. C. D. Publication, Item 857-D-1.
23 ~r~y-fQL-~y~y~l~ Martin and Latham, Page 282, 1963.
Eo~h~l~_~hi~ g__Qf_~m~ B~ iQn, Project 24 2.3-2, JANGL~, Nevada Proving Grounds, October-November 1951, ~rmed ~orce~ Special Weapons Project, Washington D.C., WT-393.

~78~72 ¦ ~he ~ffeçts Qf_~çle~r ~, Office of Technology Asses-l l sment, Congress of the United States, Library of Congress 2~ Catalog Card Number 79-600080, 1979.
3l ~ d~--Tb~ i-al-~imensiQ~--of--N~cleaL--~-L~ E.¦
l Chivian M.D., Susanna Chivian, R. J. Lifton, M.D., J. E.¦

51 Marck, M.D., page 38-39, 1982.
6¦ S~M~ARY OY T~E INVENTION
7 ¦ Tent structures are described which include disposable,l 8 exterior, semi-transparent plastic and/or fabric shield membranes¦
g coverng a tent composed of stretched, tightly woven, rip-resis-tant fabric panels supported by tensile rods/ wands. The tent 11 includes a tub floor extendin~ down into and accommodating a 12 central trench or hole. The bottom exterior edge of ~he shield 13 membrane extends into and is partially buried in a shallow ditch 14 excavated around the perimeter of the tent structure~
Contaminated and/or radioactive particles settling on the 16 exterior surface on the shield shaken or sliding off the membrane 17 are captured in the shallow trench precluding contamination of 18 the central trench or hole, and minimizing radiation scattering 19 into the central trench or hole. All above-surface components of 2~ the tent structure are composed of material~ which are essential-21 ly transparent to high-energy gamma radiation, further minimizing 22 secondary radiation scattering into the central trench or hole.
23 The interior fabric panels and tub floor of the tent structure 24 are coated with a plastic material such as urethane to render the interior es~entially air- and watertight.
2ff¦ A 31mple dust filtration system i5 incorporated into a '7897Z I I

1~ ~ panel of the outer shield membrane for removing dust contami-l 2j nants, allowing air circulation into and through the interior of l 31 the tent. Air circulation is induced by movement of the tent I
41 walls caused by wind and/or the occupants.

5~ In particular embodiments, the bottom circumferential¦

6 edge of the shield membrane is formed into a tubular enclosure¦

7 for receiving and storing water, for holding the shield membrane~

8 initially in place inside the circumferential trench. Sealable¦

9 and vented pockets for refuse and human waste are also incorpor-ated into the walls of the tub lining the hole or trench.
11 The invented tent structure has the advantage of beingl 12 easily erected over a hole or trench to provide significant 13 protection from airborne radioactive contaminants to occupants t4 who wait until either initial high-intensity radiation danger subsides or rescue occurs.
' 16 Other advantages of the invented shelter include low cost 17 mass production. The shelter can also be easily decomaninated, 18 dismantled, and moved to a different location. The shield mem-19 brane and the tub floor are replaceable. Finally, the inner tent, equipped with a conventional tub floor, can be used as a 21 conventional tent for outdoor recreation.
22 D~SCRIPTIO~ O~ T~B PIGUXRS
s~ 23 Ei~L~-l is a perspective cutaway view of the invented fallout shelter showing the interior tent structure, the shield membrane, and the tub floor extending into a central trencb.
2~ El~ 2 is a cross-sectional view of the invented porta-89~72 ~¦¦ ble fallout shelter showing a cross-section of the tent struc-21 ture, tub floor, central trench, air circulation between the 3 shield membrane and tent panels, and vented waste disposal 4 pockets.
Sl Ei~U~ is a longitudinal cross-sectional view of the 6l invented portable shelter.
7 I Ei~uLe_4 is a detail showing the manner of sec~ring the 8 circumferential edge of the shield membrane in a shallow ditch or 9 trench.
Eig~ is a detail showing the circumferential edge 11 formed into a tubular configuration for receiving and storing 12j water.
13 Ei~e_6 is a detail showing a fastening mechanism for 14 interconnecting elements of the plastic shield membrane~
Ei~ _l iS a detail showing disposable air filter moun-16 ted within a cylindrical cuff.
17 Ei~Le_~ is a detail showing mechanism for interconnect-18 ing elements of the fabric tent together.
19 Elg_~e_2 i8 a perspective cut-away view showing the ele-ments of the invented tent fallout shelter for a tent having a 21 circular configuration.
22 Eiq~L~-lQ is a detail 5howing a shock cor~ within the 23 tensile rods/wands, for resiliently supporting the tent.
24 E~g~_ll is a detil showing the manner of securing the tensile rods and wand~ at tbe ground surface.
2~ Elg~e_12 i8 a perspectiqe view of an alternative embodi-9~2 --1~ ment of a po.table t~ntlike structure supported by air-filled 21 ribs inflatable by occupants from the inside.
3 Ei~e_13 is a detail showing a simple butter~ly valve 4 system for assuring filtered air circulation into the interior of a tent structure.
6l Eig~ 14 illustrates a mechanism for circulating air 7 through the interior of the tent structure.
8 Eiq~e_l~ illustrates pockets incorporated into the walls 9 of the tub lining, with vents for receiving refuse and human waste.
11 Eig~ L_~n_(cL are top views of shield 12 membranes secured together in different configurations, illustra-13 ting temporary modular shelter structures.
14 DBSCRIPTIO~I OP TE~13 PR~PE:RRED E~BODINI~ITS
Referring now to Figures 1, 2, 3. and 9, the essential 16 components of the invented temporary/portable nuclear fallout 17 ~helter include a disposable shield membrane 11, stretched and 18 anchored over a tent 12. The tent is formed by stretched, tight-19 ly woven, rip-resistant fabric panels 13 ~upported by precurved ten~ile rods and/or wands 14. The tub or floor 16 of the tent 12 21 ha~ a central hexahedral or cylindrical-tubular ~ection 17 exten-22 ding do~n~ard, adapted to be received in and to line a ~rench or 23 foxho~e l~ ov~r which the tent 12 i5 erected.
24 ~he ~ottom circumferential edge 19 of the ~hield membrane 2S 11 extends into and i8 partially buried in a ~hallow ditch 20 26 excavated around the perimeter of the tent 12.

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1~ The circumferential edge 19 of the shield membrane may be 2 formed into a tube 21 for receiving and storing water 22. The 3 water-filled tube also serves to anchor the circumferential edges ~ of the shield membrane 11 during the initial period of occupancy.
As the water is gradually used, placement of the earth, rock, and 6 the like from the inside structure can be placed against the tube 7 1 22 for anchoring the edge of the membrane 11.
8 Alternatively, as shown in Figure 4, the shield membrane 9 11 can be anchored by 1) attaching to or wrapping its circumfer-ential edge 19 to or around a board 23 or similar weight; 2)11 placing it into a shallow ditCh 20 excavated around the perimeter 12 of the tent 12; and 3) partially burying it.
13 The shield membrane 11 is a thin sheet o plastic mater-~ ial or plastic-impregnated fabric that is waterproof and resist-ant to tearing (ripping). To prevent or minlmize overheating 16 within the structure becau8e of ab80rption of 801ar radlatlons, 17 the shield membrane 11 should be refléctive. It should also be 18 fiemi-transparent to allow the 8helter occupants to view their 19 ~urroundings. The exterior surface of the shield membrane 11 20 should al~o be sufficlently 8mooth to prevent small du~t partlc-Z1 le~ from becoming lodged in or on it, so that du8t particle that 22 settle onto the membrane 8hield can be ghaken off or di810dged by 23 ~lmply 8haking the membrane 11.
24 A suggested shield membrane material meeting the above .
25 criteria ln aluminized Mylar 8heetg. Al80, other metalized plas-2~ tic sheet material~ would be ~uitable.
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1~ The fabric panels 13 forming the inner tent structure 12, 2 the tub floor 16 and tubular extension 17 are treated or impreg-3 nated with a plastic material to prevent penetration of small 4 dust particles. In fact, it is desirable to coat the interior surfaces of the fabric panels 13 and seams between adjacent 6 panels with a plastic or other similar substance to render 7 the volume enclosed within the tent structure substantially air-8 tight. Air is then circulated into and out of the volume en-9 closed by the tent structure 12 through air filtration ports, described in greater detail, infra.
~¦ Referring to Figures 2, 3, and 14, A platform 26 formed 12¦ from a door, board, or other similar material can be placed over 13 the trench or foxhole 18 within the tent 12. In such instances, 14 dirt can then be thrown and piled on top of the platform 26 to attenuate ~skyshine~ radiations emanating from airborne radioac-16 tive particles in the atmosphere and stratosphere above the shel-17 ter. The top surface of this dirt on the platform ~hould be 18 below the horizontal ground level to prevent it from becoming a 19 secondary scattering source of radiations from radioactive dust accumulations (fallout) on the ground surface.
21 Referring now to Pigures 12 and 14, another embodlment of 22 the invented temporary/portable fallout shelter is shown which 23 comprises a single layer of material 25 composed of, for example~
24 aluminized mylar or other non-porous, lightweight, but thin strong ~heet material ~upported in a tentlike configuration by ~6 air-filled rib~ 270 The structure is anchored by a water-filled I
1l tube 22 forming its circumferential edge 19 which is received and¦
21 partially buried in a shallow ditch. The structure is erected¦
3¦ over a central ditch or foxhole 18. Alternatively, the tub floor 4 16 can be appropriately dimensioned to have sufficient slack to 5l~ extend into and line a central trench or foxhole 18 when the 6~ structure is erected.
l Ingress and egress from the described shelters are via 8 entrance port(s) 28 covered by a door or flaps 31 which include 9 means 29 for establishing a hermetic (airtlght and watertight) seal with the shoulder 32 of the entrance ports 28. In particu-11 lar, referring to Figures 6 and 8, the edge of a door flap 31 for 12 entrance port 28 through a 1) shield membrane 11, 2) fabric panel 13 13, or 3) tent wall 25 may be formed into or secured to a beaded 14 shoulder 33 which is adapted to be snugly or compressively re-ceived in a correspondingly shaped channel 34 forming the should-16 er 32 of the entrance ports 2B.
17 Pigure 8 illustrates another embodiment of a fastening 18 mechanis~ wherein the edge of the door flap 31 and the shoulder 19 32 of the entrance port 28 are formed into and/or secured to hook channels 36. The hook channels are rotated 180 degrees with 21 respect to each other such that the tip section o~ each channel 22 36 is snugly and compressively received between the tip and shank 23 othe other hook channel. Similar fastening mechanisms, as illus-24 trated in Pigures 6 and 8, may be utilzied to cover and seal other access ports through 1) the shield membrane 119 2) a fabric 2~1 panel 13, 3) the ten~ wall 25, and/or 4) tub floor 16. The , ~ 372 1~ essential criteria in choosing the fastening mechanisms is that 21 the mechanism when fastened must minimize or preclude dust infil-3 tration into the interior 37 of the tent shelter.
4 Sealing and fastening mechanisms may also be utilized for securing together several shield membranes ll and/or fabric pan-6 els 13 to form modular structures. As shown in Figures 16(a), 7 (b) and (c), dust-tight fastening mechanisms interconnect modular 8 tent structures 38 and their associated shield membranes ll. In 9 Figure 16(a), a structure 39 is formed by two modular tent units 38, each with a tapered (conelike) end 40. Figure 16(b) shows a 11 structure 41 formed of two modular tent units 38, two end units 12 with tapered ends 40, and a central unit 42 without a tapered end ~31 40. Pigure 16(c) shows still another structure 43 again formed 14 of two end units tapered ends 40, a central unit 42, a modular tent unit 38, and a right-angle unit 44.
16 As illustrated in ~igure l, each of the modular units 17 forming the structures 39, 41, and 43 would in~lude a central 18 tubular hexahedral section 18 in the tub floor 16 which extends 19 downward into a trench 18 over which the modular ~tructure is erected. The hexahedral sections 17 in the tub floor of the 21 modular tent unit include appropriately located access ports 22 through side walls, including cover flaps for establishing a 23 du~t-tight seal over the port, air filters, ~aste receptacles, 24 and transparent and/or seml-transparent windows.
Referring now to Pigure3 9 and 10, the ten3ile rods or 26 wands 14 supporting the tent structure may be formed from hollow ~7~7;~;
1~; tubes of fiberglass, aluminum, or other lightweight~ resilient, 2¦ rigid material. The rods/wands 14 may also be precurved. The 3l rods or wands 14 can be formed by a plurality of interconnecting 4 short, hollow sections 46, each having a rodlike tip 43 being received in a hollow cylindrical base 48 of the next section. An 6 elastic shock cord 49 is strung through the center of the hollow 7 I sections 42 making up the rod or wand 14 for holding the 8 sections 46 in a proper sequential arrangement, yet allowing the 9 wand to be taken apart and folded up and stored in a small space.
Referring to Figures 1, 9 and 11, the rods or wands 14 11 are received in tubular webs 45 integrally a part of, sewn, or 12 otherwise secured to the fabric panels 13, forming the tent 12.
13 The ends of the rods or wands 14 include a small diameter anchor 14 tip 51 adapted to be received in a metal grommet ring 52 through a strap 53 formed into a loop with both ends of the strap 53 16 being sewn or secured to the perimeter of the tub or floor 17 of 17 the tent 12. The anchor tips 51 at each end of the rod 14 are 18 received in grommet rings 52 on diametrically opposite sides of 19 the tent. ~he resulting elastic tension of the curved rod holds the tent erect and stretche~ the tub or floor 16 of the tent.
21 The combination of the curved tensile rods 14, held by 22 the webbing tubes 45, stretc`hed fabric panels 13 and ~tretched 23 tub 16 provides a stable, sturdy, free-standing enclo~ure. Addl-24 tional ~tability, particularly against heavy winds, can be pro-vlded to the tent 12 by tying the tent down to a plurality of 26 ground ~take~ 54 secured to the loops formed by the straps 53 by an appropriate cord 56. Such stakes 52 should be located between 2 the peri~eter of the tub 16 and the ditch 21 receiving the cir-3 cumferential edge 19 of the shield membrane 11.
4 Referring now to Figures 2, 13, and 15, air circulates into the interior spaces of the tent 12 through filters 57. The 6 air filters may be incorporated into the shield membrane 11 and 7 the fabric panel 13, forming the tent. New filters can be inser-8 ted from the inside in a manner that pushes out the contaminated filter to the outside, where it fal~s into the circumferential ditch.
11 For example, referring to Figure 7, a disposable air filter element 57 is fastened within a cuff 58 which in turn is sewn or secured to a mesh opening through one of the fabric 14 panels 13, forming the wall of the tent 12. The perimeter of the filter element 57 and the corresponding free end of the cuff 58 16 are hermatically joined together to form a du~t-tight seal. In 17 the embodiment illustrated, the perimeter edge of the disposable 18 filter element 58 includes a necked channel 34 of the type shown 19 in Figure 6, and the di~tal end of the cuff 58 includes a beaded shoulder 33 adapted to be received in the neck channel 34 of the 21 filter element.
22 ~eferring now to Figure 7, the disposable air filter 57 23 i~ recelved within the interior of a rectangular sleeve or cuff 24 58 formed of flexible but airtight material~ The shoulder 59 of the cuff 58 i8 sewn or otherwise secured to the fabric panel 13, 26 forming a ~all of the tent 12. ~esh fabric 60 maintains the '',, '~: ' , .':.

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1 integrity of the fabric panel 13 while letting air flow into the 2 cuff 58. A slightly elastic, flexible beaded edge 33 is sewn or 3 attached around the distal end of the cuff. The disposable 4 filter element 57 includes a frame 55 formed of a relatively l;~
rigid material having an exterior annular groove 34 with the 6 configuration adapted to snugly receive th~ beaded edge 33 of the 7 cuff 58. Suitable air filtering materials are mounted and sec-8 ured within the frame 55~ ¦
9 The air filter57 should be protected from rain and other precipitation ~uch that the contaminants filtered from the air 1, 11 are not subsequently leached from the air filter material by 12 water ~nder incle~ent weather conditions. For example, in the 13 embodiments of the shelter shown in Figures 1, 2, 3 and 9, the 14 air filter is protected through the inner tent from precipitation by the exterior shield membrane 11. In embodiments not having an 16 exterior shield membrane 11, and for air filters through the 17 membrane, a drip curtain or shield protects the filter and 18 opening from precipitation.
19 Referrlng to Figures 12 and 13, an e~terior cuff is formed of flexible material and secured to the exterior wall of 21 the tent 12 such that the cuff opening 62 face~ downward. A
22 disposable air filter element 57 is positioned within the over-23 hang 61 at a sufficient distance from the opening 62 to prevent 24 the filter element from getting wet. The filter element 57 is again ~ee~red within the sleeve by suitable dust-tight fastening 26 mechanisms of the type shown in Figures 6 and 8. There are holes ~'7~9~2 1 63 through the fabric or plastic panel 13 forming the wall of 2 the tent 12 to allow air to circulate into the cuff opening 62 3 through the filter element 57 and into the interior of the tent 4 12. A flap of flexible material 64 is included on the interior side of the disposable filter element 57 within the overhang 61 6 to provide a simple butterfly valve to prevent air from flowing 7 out of the tent thEough the filter. A second butterfly valve 66 8 is incorporated into the fabric or plastic panel forming the 9 shield or wall of the opposite end of the tent which only allows air to flow from the interior of the tent to the 11 exterior.
12 Care must be taken in locating the air filter 13 openings/cuffs. Specifically, the filter elements, as 14 contaminants are collected, will become a radiating source which can "shine" into the trench or hole if located on the 16 upper or top surfaces of the tent shelter. Yet, if the filter 17 were located ~lose to the yround surface, it would be subject 18 to clogging and contamination due to surface dust. Ideally, 19 the air filter and associated openings are at positions on the tent structure which minimize shine into the trench or hole, 21 sufficiently above the ground surface to prevent clogging and 22 excessive contamination due to surface dust. (See Figure 3.) 23 In some cases it may even be desirable for the occupants to 24 be able to change the filter. Accordingly, the filter opening through the shield membrane should be located adjacent to or 26 accessible from access ports through the interior tent walls.
27 Referring now to Figure 15, the waste/refuse pockets ~ ~ 2 1~ incorporated into the walls of the tub lining include vent tubes 2 which extend upwardly to a point proximate the ground surface.
The pockets each have a hermetic closure mechanism to prevent the vapors emanating from the refuse/waste from smelling up the interior~

6 The excavation of the trench or hole in the ground can be 7 done by hand with a shovel. Alternatively, the tent structure 8 may be received in a preplanned, below-surface concrete trench or 9 foxhole. In the latter instance, it would be feasibie to quickly excavate a buried concrete trench and the like using shaped 11 explosives.

12 The invented temporary/portable fallout shelter has been 13 described in context of schematic and representative embodiments.

14 Many variations and modifications can be made to the invented shelter which, while not described herein, fall within the spirit 16 and the scope of the invention as described in the appended 17 claims.

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Claims (16)

1) A portable shelter for placement over a hole in the ground comprising in combination, a tent enclosure having a floor with a tubular section extendable downwardly therefrom, means for supporting the tent enclosure to form an en-closed volume above the hole, the tubular section of the tub floor extending downwardly into and lining the hole, a shield membrane approximately dimensioned and having sufficient surface area to completely cover the tent enclosure when erected, with its circumferential edge extending into and partially buried in a shallow trench excavated around the tent enclosure and hole.

2) The portable shelter of Claim 1, wherein the shield membrane has a circumferential edge formed by a tubular enclosure integral with the membrane.

3) The portable shelter of Claim 2, wherein the tubular enclosure forming the circumferential edge of the shield membrane is hermetic to provide fluid storage.

4) The portable shelter of Claim 3, further including means communicating with the tubular enclosure forming the cir-cumferential edge of the whield membrane for introducing and drain-ing fluids into and from the tubular enclosure.

5) The portable shelter of Claim 1, wherein the tent enclosure including the tubular section extendable from the floor are formed by tightly woven, rip-resistant panels joined together.

6) The portable shelter of Claim 5, wherein the shield membrane is a coated, rip-resistant plastic sheet material re-flective of solar radiations.

7) The portable shelter of Claim 5, wherein the inter-ior surfaces of the fabric panels and junctions between each panel are coated with a sealing material for rendering the tent enclosure essentially airtight.

8) A portable fallout shelter for use in combination with a hole in the ground comprising:
a tent enclosure formed of a hermetic flexible material, including:
a plurality of inflatable tubular rib sections, a circumferential edge formed into a tubular section for containing water extending from the exterior perimeter of the tent enclosure, a floor having sufficient slack to extend downwardly into the hole for lining the hole, the tent enclosure being erected by inflating the inflatable tubular sections with a gas, the enclosure being anchored by filling the tubular section forming the circumferential edge with water and partially burying the water-filled circumferential edge in a shallow trench excavated around the perimeter of the enclo-sure.

9) The portable fallout shelter of Claim 8, further including an access port through a side wall of the enclosure and means for closing and hermetically sealing the access port from the interior of the enclosure.

10) The portable fallout shelter of Claim 9 or 5, fur-ther including means for circulating and filtering air into and out of the enclosure.

11) The portable fallout shelter of Claim 5, further including pockets incorporated into the lining of the tubular section extending downwardly, the pockets opening into the tent enclosure, and means for hermetically sealing and isolating the pockets from the interior of the tent enclosure.

12) The portable fallout shelter of Claim 11, wherein the pockets include vent tubes for allowing vapors emanating from wastes placed in the pockets to escape, and means located distant from the pocket for preventing gas flow through the tub into the pocket.

13) The portable fallout shelter of Claim 1, further including walls and and a floor composed of concrete type materi-als forming a trench below the ground surface over which the tent enclosure is erected, the tubular section of the enclosure hav-ing a hexahedral configuration for lining the trench.

14) The portable fallout shelter of Claim 13, wherein the trench has been filled with dirt, and including means for explosively excavating the dirt from the trench.

15) The portable fallout shelter of Claim 7, wherein the tent enclosure is formed of at least two modular unit enclosures connected together, each unit enclosure including a separate hexahedral tubular section extending downward from its floor, further including:
means for allowing occupants to move between the hexahe-dral tubular sections of the respective unit enclosures, and means for hermetically isolating the respective hexahe-dral tubular sections from each other.

16) The shelter of Claim 1, wherein the shield membrane is formed of at least two (2) modular membrane sheets, each sheet having means forming its circumferential edge for hermetic en-gagement with similar means, forming the circumferential edge of the remaining sheets.