PRINCIPLES OF NAVAL ENGINEERING 



3.193 



Figure 4-9.— Water washdown system in operation. 



Chemical Decontamination 



The major problem in chemical decontami- 

 nation is to decontaminate successfully after an 

 attack by any of the blister or nerve agents. 

 The general methods used in chemical decon- 

 tamination include natural weathering, chemical 

 action, the use of heat, the use of sealing, and 

 physical removal. 



Natural weathering relies on the effects of 

 sun, rain, and wind to dissipate, evaporate, or 

 decompose chemical agents. Weathering is by 

 far the simplest and most widely applicable 

 method of chemical decontamination; in some 

 cases, it offers the only practicable means of 

 neutralizing the effects of chemical agents, 

 particularly where large areas are contami- 

 nated. 



Decontamination by chemical action involves 

 a chemical reaction between the chemical agent 

 and the chemical decontaminant. The reaction 

 usually results in the formation of a harmless 

 new compound or a compound which can be 

 removed more easily than the original agent. 

 Neutralization of chemical agents can result 

 from chemical reactions of oxidation, chlorina- 

 tion, reduction, or hydrolysis. 



Expendable objects or objects of little value 

 may be burned if they become contaminated. 

 This procedure should not be used except as an 



emergency measure or as a means of disposing 

 of material which has been highly contaminated. 

 If this method is used, a very hot fire must be 

 used. Intense heat is necessary for destruction 

 of chemical agents; moderate or low heat may 

 serve only to volatilize the agent and spread it 

 by means of secondary aerosols. When a large 

 amount of highly contaminated material is being 

 burned, downwind areas may contain a dangerous 



fSr-^ 



8.100 

 Figure 4-10.— Decontamination by manual 

 scrubbing. 



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