ISO 22324

This document provide guidelines for color codes to indicate severity of hazards in public warnings.

There are many different systems are already in use, such as colour state of meteorological condition or former Homeland Security Advisory System, and the standard is intended to be an approach to eliminate confusion due to such differences.

[3] If more than three levels of hazards are needed, the standard recommends use of colors on the spectrum between the red and green.

The standard recommends to pay special care to provide supporting information, such as: The standard gives additional color codes for supplementary information, defined with meaning and usage limitation, as in following table.

Each color code has saturated and unsaturated cases, both defined in Munsell, CMYK, and RGB systems.