As a firefighter, you find yourself at the bottom of a burning high rise. A resident is trapped on a floor which is 140 m from you and the street. Your team has spread the Life Safety Net for the resident to jump onto safetly. The siren is shut off. The nosey spectators are quiet. However, it is a busy street.
How loud, in decibels, should your bullhorn be in order for the resident to hear you?