Radiation warning sign

Radioactivity warning sign

The radiation warning sign (also radiation sign , impeller or Trefoil ( English for clover, three-leaf )) is the warning sign for radioactivity or ionizing radiation . It is regulated in the ISO standard ISO 361 .

history

In 1946, a small team of researchers from the radiation laboratories at the University of California at Berkeley conducted an internal vote to find a suitable radioactivity warning symbol. The symbol was originally shown in the color magenta on a blue background, whereby it only consisted of three equilateral triangles touching at one point. However, the blue background did not make sense and so after a few attempts at the end of the 1950s, the magenta-colored symbol on a yellow background was standardized by the American National Standards Institute .

Internationally, however, the symbol was standardized in black on a yellow background. In the meantime, this international version (in addition to the US version) is also allowed in the United States .

Original version in magenta and blue
US version
International version

use

The radiation warning sign is attached to shielding containers for radioactive substances, if the radioactive substances are of the appropriate size, partly on them, on doors of rooms in which there are radioactive substances or devices that can generate ionizing radiation (e.g. X-ray machines). The radiation warning sign can also be found on fences or barriers to contaminated sites or building complexes that contain radioactive substances (e.g. warehouses, factories, nuclear power plants ). Vehicles that transport radioactive substances also carry the radiation warning sign.

Supplementary symbol

New warning sign directly on dangerous radioactive emitters

On February 15, 2007, the International Atomic Energy Agency announced that it would add a new, even more deterrent symbol to the radiation warning sign, standardized as ISO 21482 , which is to be attached directly to dangerous emitters of radiation categories 1, 2 and 3 to avoid the danger of these substances and to make it clear to laypeople how to behave correctly , as the abstract Trefoil itself was often not properly understood, especially by children or in developing countries (children sometimes thought it was a propeller ).