Sunday, August 12, 2012
Why are fire hydrants different colors?
Fire hydrants are painted different colors to reflect the amount of water they can expel. Blue hydrants can expel the most at 1500+ gallons per minute (gpm). Green hydrants expel 1000-1500 gpm, orange/yellow hydrants 500-1000 gpm, and red hydrants <500 gpm. In certain cities, the knobs on each hydrant are painted different colors to indicate the pressure of each hydrant. Green knobs indicate a pressure of over 120 pounds per square inch (psi), orange knobs 50-120 psi, and red knobs <50 psi. When firefighters arrive at a scene, they need to be able to quickly identify what is needed to suppress the fire. They need to know how much water is readily available so they can tap other resources if necessary. The color-coated hydrants/knobs assist firefighters in their initial assessment of available resources.