Radiation Warning Signs -


There are three types of radiation warning signs used for ionizing radiation sources other than radioactive materials. These are; Caution-Radiation Area, (click on radsign below), Caution (or Danger) High Radiation Area, and Grave Danger, Very High Radiation Area. All of these use the magenta or black three bladed propeller symbol with the words in the same color, on a bright yellow background. The lowest level of sign is required when there exists ionizing radiation at such levels that a major portion of the body could receive in any one hour an exposure dose in excess of 5 millirems. Remember, a simple chest x-ray examination could result in an exposure equal to or greater than that amount if you are within the primary beam area. For this reason it is important to monitor your exposure to determine if your work habits are causing you to be exposed to excessive amounts of radiation. Although you may have tried monitoring in the past and concluded that a badge was no longer necessary because no readings were recorded there are several reasons why you may need to reconsider at this time. If the badge was improperly shielded or the control badge was not stored in a radiation free area you could have had readings that were deceptively low. If you have changed the building structure, especially as regards any shielding you may be exposed to higher levels of radiation then in the past. If you have purchased a new x-ray machine, had major changes to the existing machine, have experienced an increased workload or hired a new employee whose work habits are not yet proven these could affect exposures received by all personnel in the area. The exposure level which requires monitoring has been lowered, and the limits to the general public are now one-fiftieth the occupational limit so that a determination of whether or not to monitor based on old standards may no longer be appropriate. Also, if you have a pregnant or potentially pregnant employee it could be especially important to be able to prove that exposures have not been excessive. Unless you regularly use health physics services to measure radiation safety factors in your facility, the personnel monitoring reports may be your only document for defense in the event of litigation claiming you provide an unsafe work environment. In addition to the Radiation Area sign used when exposure levels are greater than 5 millirems per hour, a High Radiation Area is any area, accessible to individuals, in which there exists ionizing radiation levels that could result in an individual receiving a dose equivalent in excess of 0.1 rem (1 millisievert) in one hour at 30 centimeters from the radiation source. A relatively new category of exposure level which requires a still different sign is the Very High Radiation Area. The is an area, accessible to individuals, in which radiation levels could result in an individual receiving an absorbed dose in excess of 500 rads (5 grays) in 1 hour at 1 meter from a radiation source or from any surface that the radiation penetrates. The approprite warning sign for this highest level will display the three bladed propellar (trifoil) symbol, with the words "GRAVE DANGER, VERY HIGH RADIATION AREA."

More options......

Display Radiation Sign - >0.005 R level
Radiological Health in Alaska