234 Posting Radiation Areas
Areas shall be posted to alert individuals to the presence of external radiation in accordance with Table 2-3 [see
835.601, 603]. In addition, hot spots should be labeled as described below to provide warning of discrete radiation
Radiation areas and high radiation areas shall be identified based on the dose rates at a distance of 30 centimeters
either from the source or from any surface penetrated by the radiation [see 835.2(a), radiation area and high
radiation area]. Very high radiation areas shall be identified based on the dose rate at a distance of 100 centimeters
either from the source or from any surface penetrated by the radiation [see 835.2(a), very high radiation area].
Hot spots are localized sources of radiation, normally located within piping or components, with contact radiation
levels greater than 100 millirem per hour (penetrating radiation dose) and more than 5 times greater than the general
area dose rate. Contact readings should be used to determine the need for labeling hot spots. Measures taken to
identify sources of elevated general area radiation levels while conducting routine radiation surveys should be
sufficient to identify hot spot locations. Special surveys for the sole purpose of identifying hot spots are not
A label reading "Caution, Hot Spot" and marking the location of the hot spot should be placed on or as near the spot
as practicable. The provisions of Article 231.7 through 231.11 do not apply to the hot spot labeling. Labeling of
hot spots is not required in areas with general area dose rates greater than 1 rem/hr. However, the locations of such
hot spots should be noted on area surveys and discussed in pre-job briefings.
Dose received in an hour may be used as the criterion for posting (Column 2 of Table 2-3). At very high doses
received at high dose rates (such as doses received in a very high radiation area), dose rates should be measured and
recorded in units of "rads" rather than "rem" in an hour.