The international distinctive sign of civil defence is an equilateral blue triangle on an orange ground when used for the protection of civil defence organizations, their personnel, buildings and material and for civilian shelters. (item 4, Article 66 of Protocol Additional to the Geneva Conventions of 12 August 1949).
It is recommended that if the blue triangle is on a flag or armlet or tabard;
The symbol is now commonly used across the world to denote those operating in the civil defence, resilience and continuity fields.