PERSISTENCY TIMES OF CHEM AGENTS ON CARC VEHICLES

File: 970612_sep96_decls11_0002.txt
Page: 0002
Total Pages: 4
Subject = PERSISTENCY TIMES OF CHEM AGENTS ON CARC VEHICLES               

Parent Organization = ARCENT      

Unit = XVIII CORPS 

Folder Title = NBC LOGS AND MESSAGES-1                                                                         

Document Number =         19

Box ID = BX000095






                                       UNCLAS



    COORDINATING DRAFT. YHE PERSISTENCY TIMES ON SAND (TABLE 2) ARE
    BASED ON MODELING RESULTS USING-NUSSE4 METHODOLOGY, THE ARMY'S
    STANDARD MODEL FOR ATMOSPHERIC DISPERSION AND SURFACE EVAPORATION
    OF CHEMICAL AGENTS. SINCE-NUSSE4 METHODOLOGY APPLIES ONLY TO
    GRASSLAND, A CORRECTION FACTOR OF 2.5 HAS BEEN APPLIED TO DERIVE
    THE RESULTS IN TABLE 2, AS RECOMMENDED IN FM 3--4. THE PERSISTENCY
    TIMES LISTED BELOW (FOR BOTH SURFACES) ARE THE TIMES TO ACHIEVE
    90 PERCENT EVAPORATION OF THE ORIGINAL CONTAMINATION.





    PAGE 03 RULNEAA0047 UNCLAS
         TABLE 1: PERSISTENCY TIMES OF CHEMICAL AGENT ON
                    CARC  PAINTED VEHICLES
                          TEMP (DES F)
         AGENT            50                 77                 IIID
         GF               9 HR               4 HR               I HR
         GA (OR HD)       12 HR              5 HR               I HR
         BB               15 MIN             7 MIN              2 MIN
         TABLE 2: PERSISTENCY     TIMES OF  CHEMICAL AGENT ON   SAND
                          TEMP (DEG F)
         AGENT            50                 77                 II()
         GF               93 HRS             22 HRS             5 tiRS
         GA (OR HD)       100 HRS            27 HRS             '7 1-iRS
         BB               2 HRS              1 HR               < I HR
    2. WE   BELIEVE  THESE ESTIMATES OF    PERSISTENCY TO BE   SAFE-SIDED
    BASED ON THE PARTICLE SIZE ASSUMED IN FM 3-4. TO BE CONSERVATIVE,
                                                                  WE BELIEVE
                                                              ATION DESERT
    SHIELD THREAT WEAPON SYSTEMS) WILL RANGE FROM .7@00 Tn IOOO MICRONA,
    (@).3 TO I MM). SINCE PARTICLE SIZE IS APPROXTt'[ATPLY PR-.OPnF.-TTnNAI
    TO PERSIEiT-ENdY TIME7 PERSISTENCY-TIMES W5-UL-D BE dllQR@TF-R@FOR




    PAGE 04 RULNEAA0047 UNCLAS
    SMALLER AGENT DROPLETS. TO ESTIMATE PERSISTENCY TIMES FOR THESE
    SMALLER DROPLETS, SIMPLY APPLY'A CORRECTION FACTOR. FOR EXAMPLE,
    A 1000 MICRON DROPLET WILL-HAVE A PERSIqTFNC,'y TIME APPROXIMATELY
    40 PERCEffT O@F TFI@AT LISTE@D IN@THE TABLES (1000/2500 = 0.41
    3. TRE-PERSISTENCY Tlmrm-s-A-R-E-,,!@L-sO AFFECTED BY METE@OROLOGICAL
    CONDITIONS. ALL PERSISTENCY TIMES LISTED ABOVE ASSUME A WIND
    SPEED OF 3 M/S (6 KNOTS). HIGHER_AIND.SPEEDS THAN THIS WILL
    GENERALLY PRODUCE SHORTER PERSISTENCY TIMES; AND LOWER WIND SPEEDS
    WILL PRODUEE L@ONSER@PERSISTENCY TIMES. ALSO NOTE THAT AT MODERATE
    TO HIGH AIR TEMPERATURES AND SIGNIFICANT LEVELS OF SLLNLIGHT, THE
    VEHICLE AND SAND SURFACES WILL LIKELY BE MUCH WARMER THAN AI@



                                       UNCLAS