Flame blue is the color of fireman's uniform. Because flames produce blue when the temperature is extremely high, "flame blue" is used to describe firefighters. Blue symbolizes the high temperature and purity of the flame, and implies the determination and enthusiasm of firefighters to protect the people.
In addition, firefighters are often described as "night watchman". Firefighters always stick to their posts, serve the people wholeheartedly, and go through fire and water during major festivals and sensitive periods to protect people's lives and property.