Document 4YzY8J808BKqpNQ4MVzGd28x

imw l w w .h i mt s s w '-pin 1 iuranssnawwn w s w ub m.t ,N^NWH'e.mi' n 'ymwu^iM-iw.--n LIA24643 > h^* hlSltiaf I TiTtfTn ii`ijssiTiii ihf m -fl2vfc wMlX. LEAD INDUSTRIES ASSOCIATION SSt MADISON tVINUI NEW TONE IT. N.T. j ` ] lomAtr 6, 1^61 SUBJECT! COMPREBBOIVE topHT OS LEAP Dl FAUOUT SKELTERS To Herbert of ths Lsad Industries Associations V have oov prepares a *uch core cccprehenslve report, as attaches, cc the use of lead In the construction of fallout shelters. Ve plan 00 using this to snsver future Inquiries la place of the report sent to you on October 16, 196l. Additional copies up to tvcity-flre any he had free of charge 00 request, larger quantities at hf per copy. If you need additional copies, please let us know. Sincerely yours. 1 David N. Borclaa DC:HM< L.MW>JBBII I u-||giantilunW|,<qa sv LIA2A6AA liTHaafa.ii a.--...n a a n HI I I.III JKIM nnitim lH aaaaim I in . . . a n a iu m a M lm n a m .n jr n H a . LEAD INDUSTRIES ASSOCIATION X HADIION AVKNUI wrw v o mk 17. n . r. Deviaioa 10/M/61 o LEAD III FALLOUT SHELTERS Amonj the amy commonly iniliblt materials for mein the construction of fallout shelters, 'tad. in terms of weight and apace, proridea the moat effi cient ahield againat gamaaa raya-- the priaie dangerous radiation to be expected in fallout. The rraaon for thia ia that the degree of protection or `attenuation* afforded by any arterial ia cloarly related to it* am. Therefore, lead being the taoat oaaaire common ahielding arterial ia correapoadingly oore efficient and therefore thinner and lighter than other equivalent ahielda. there weight and apace are not critical, howerer, and coat ia a major factor, other ma te r i a 1 a may be aelected either alone or in combination with lead. The following table taken from the Atonic F.nergy Commiaaion manual en titled " CFX 58.8" indicator `'barrier** or "ahield" thicknesses required for aaeioua degreea of protection or "attenuation" againat fallout. Approximate Attenuation Factors for Gama Raya Iron Fission Products as a Function of Shield Thickness for indicated Materials Shield thiemess fo* Indicated materials, in inches Attefliuttofl factor 7 to 50 IOC l.ecc 1C,000 100.000 (710 It CO ft) o.;t 9.44 l.C 1.7 2.1 7.5 4.) Iron A $tet (190 Co ft) f., y 1.1 2.1 4.7 4. a 1.9 U CcncrtU (IW It Co ft) 7.5 4.4 4.2 14 14 77 7f >7 C4ftt (10* It CO ft) 7.4 1.4 17 20 27 77 >4 44 Water (*7.4 It c ft) 4.4 17 it 74 77 5 54 70 Wood (fir) in it c ft) 4.7 75 74 5$ 47 1 110 14 0 There ia some question about the amount and energy of gameia radiation to be protected againat and, aa a function of thia, the shielding required. Data in the above table and in recommendations of the Office of Civil Defense Mobi I i tatior , OCDM, ere baa'.u on a minimum protection factor of 100 and an assumed energy of .? Mev. The figure 100 amply means a barrier with thia factor will reduce intensity inside the shelter to 1/100 of its intensity out ride at any gi veo moment. Mcv. mesne million eleelronvolta, a measure of energy, Using thia baaic data, and assuming a shelter built in the basement (below grade) of an average two atory frame house. OON rerosraends 8* of concrete of a density equal to 144 lbs. per cu. ft. or its equivalent. Since quick refer ence to the above table reveals an attenuation factor of only about S for thia mmm 'TAPI I N 1737.01 -t--- --^ii i>-riii f ' in-irairmir r- rn Vii`li^r-'i --^ LI A2A6/>5 : o tbicknesa of concrete, it Ucosei vi<ihl lhat the roof, floor*, and earth bout thi tilli of .h* cellar at contributing the remainder of the protection factor of 100. Should thia na skelter be built outside, afrove ground, tka required thickness of concrete would be 16*. Another source of confusion cooes from differing views of none euthoritiea -a to radiation energies to be expected. Energies of fron 1.4 to 2 or 3 Mev. have been suggested. Naturally, fsi heavier shields would be required in these cases. Additionally, some authorities recommend higher protection factors and, in fact, aaauaing the worst weather conditions, addition of cobalt or other iaotopea to weapons or the possibility of repeated bombings, factors up to 2,800 have been used. In any event, if discrepancies eaist between one set of recommendations and another, check these two items: radiation energies ex* pected and protection factors used. Based on the aisisvn adequate factor of 100 ( for . 7 Mev. radiation) however, the ectual construction of a basement shelter poses several problems. It is important to note, again referring to the table, that the concrete used in building fallout shelters should have a density of 144 lb. per cw. ft. This means an 8* concrete watt will weigh approximately 96 lb. per aq. ft. and a wall 8* high will weigh roughly 770 lb. a running ft. The construction of the concrete walla may not pose a serious problem but the ceiling is another master. The concrete for the ceiling of a shelter 10 x 10 ft. will weigh roughly 10,000 lb Lead on the other hand will weigh roughly 6,000 lb. and require only 1* of heed room rather than the 8* required if concrete is used. Lead also offers advantages for use in doore. hatches, window coverings, atop shallow underground shelters and other critical areas. Composite materials such as lead and concrete, lead and earth, or lead and steel are other structural possibilities. The necessary thickness of the various materials making up the composite is not a straight interpolation of the figurea given in the table. Several acceptable composites are shown on the following page*. For others it is suggested that AEC or OCDM be contacted for advice. Lead for gamwa shielding is available in a number of forma, such as sheet, brick, shot or wool. Lead shot can be cold poured into difficult to protect areas or contained in a steel shell for nse in doors, batches, etc. Lead wool is an ideal calking material for joints in whatever material or materials are selected for the shelter..Leaded gla^a, which can contain more than 50S lead by weight is available and can be used for viewing porta where desirable. i ---- --.j i uy p 'Wf^M'ii wap !( *** LIA24646 -T-.l**- --i!l"T i -|-c- f, -.^Ka^RR^.----* --- '* "- lfcV ~ - - >-'---*^L^v--*^ -- -3- ,,\*/.V<\TV LEAD- COKCiUTE. /4/. > 4; * 4-*^*-^* *> * *" 44 **.r.4*v#'. 4*. y*-4 A*\< i'f.h 4n COMPOSITES WITH FALLOUT PROTECTION iQOAL TO A%4>V**V^ OR EXCEEDING A INCHES Of 144 Ib/can. * *.`4 . * -4, ,* .4 *.4>`f.'4.y, >* * ****< * v -virA CONCRETE AT .7 Mc.v. (w e ig h t s o f l e a d - 20 lb. LIAO <>.'. >.>-*:* .135" THICK. PtmOUAAt FOOT- ARE STANDARD AMO x COMMERCIALLY AYAIU41.1) '*. 4-4 4 4 ^24 lb- .4oo* coscirr11 - V<> *> -C,'*..V. *>* '4 r5 H k J w* 4. m*4.-*4 i* 4t.4v ,t ,.! *'A.jli * LXCfctOS REQUIREMENT o i 0 ! WW,. ;!!"W:y*1WB'JW LIA24647 -di ufa'i, II iafcCiWiTrti .*.!>. In ,.,*V*/#*V'*****!.i .:::K :v:*;*..* ># ; A. % %,* ?Olb.lW -4- UAD-UPJH COMPOSITE? WtTH FALLOUT PAOTECTIOH EQUAL TO Oft. tACftfcOlHG &" of 144 lbVcu.FI.CONC*m AT .7 May. WEIGHT* OF LEAO PLR.SQ4HP.E FT. AM STAN DA mo A WO c o mme r c ia l l y AVAILABLE VWGHT Of tAKTH FlCuAfcO AJ IOO lb,/<M.FT. EAATH THICKNESS A OIVIW To WtAMST IMCHAbOV* LACCtDS KLQUlKLMEMT. UIA24648 "5- -iafcfiniv%r- 9 LEAP-STEEL COM PQS1 T E S WITH FALLOUT PROTECTION EQUAL TO OR. EACLEOING >" OF 144 Ib/CU. FT. COHCmrfc AT .7 MCV. WtlGMM OF LEAD - PER SQUARC FOOT* ARE 5TAH0AM) AMO COiAMEAClAUf AVAiLAMC* 2Olb.lU0 24- lb, .400" ^XXxVN'- ' - JOIb. .500" ^ =J 40 tb. .64-7 PsTEEtSt I >Co t; GOlb. l.ooo" + t*CE.tO* RtQUIB.thAtt.NT. o