PART A - COMPUTE THE TIME OF STAY IN A FALLOUT AREA
USING THE TOTAL DOSE (FALLOUT) NOMOGRAM
The time of stay can be computed for units crossing a fallout area if the speed and distance is known.
Use the formula
distance
time =
speed. As an example, if a unit is traveling at 10 kmph along a route 15km long,
To determine the maximum time personnel can stay in a fallout area without exceeding a commander's
operational exposure guidance, (OEG), using the total dose nomogram (Figure 4-1), you must know:
■
The total dose.
■
The H + 1 hour dose rate.
■
The time of entry.
■
How to extract the time of stay from the nomogram.
1.
Determine the Total Dose.
The total dose to be received by personnel while crossing or occupying a fallout area is normally based
on the OEG established by the commander. If personnel are protected by some type of shielding, the
transmission factor must be applied to the OEG dose to determine the total outside dose to be used on
the nomogram.
2.
Determine the H + 1 Hour Dose Rate.
The H + 1 hour dose rate can be estimated from the radiation contamination plot from the situation map.
If the personnel are crossing the fallout area, the dose rate will be averaged by using one half of the
maximum dose rate encountered.
3.
Determine the Time of Entry.
The time of entry normally will be determined by the individual directing the personnel into the fallout
area. This decision will usually be dictated by the urgency of the crossing or occupation of the fallout
area.
4.
Extract the Time of Stay from the Nomogram.
When the total dose, dose rate, and time of entry are known, the time of stay in the fallout area can be
determined from the Total Dose (Fallout) Nomogram (Figure 4-1) using the following procedures.
CM2308
4-2
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