DETERMINE RADIATION DECAY FACTORS
Critical Task: 031-506-3023
In this lesson, you will learn to determine radiation decay factors.
TERMINAL LEARNING OBJECTIVE:
You will determine radiation decay factors.
CONDITION:You will be given information about and illustrations of the procedures for determining
radiation decay factors including calculation of the time of burst (H-hour) and
STANDARD: You will demonstrate competency of the task skills and knowledge by responding to the
multiple-choice test covering the procedures for determining radiation decay
The material contained in this lesson was derived from FM 3-3-1 and STP 3-
You must be able to use radiological monitoring information to determine H-hour and to decide whether
radiation is decaying at a standard or nonstandard rate. Personnel assigned to the NBCC must be familiar
with procedures for calculating residual radiation hazards. The NBCC converts raw data received from
many sources. A sequence of dose rate readings from several selected locations is required.
PART A: DESCRIBE THE PURPOSE OF DECAY FACTORS
contaminated areas, and decay at different rates at different times. Detection of new contamination will
initially be in the form of contact reports from units, patrols, or observers. These reports will alert the
command to the presence of a previously undetected hazard and cause a new series of orders to be
initiated for radiological information.
4-2. Dose Rate Information. During the evaluation process, monitoring or survey reports will provide
dose rate information about the contaminated area. This dose rate information must be converted to the
ground dose rates existing at a reference time, normally H + 1 for all contamination. To accomplish
processing and to calculate doses from the resulting intelligence, a reference time (H-hour) must be