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 are second with 1000-1500 gpm; orange/yellow hydrants are next with 500-1000 gpm; red hydrants have the slowest water output at <500 gpm. In certain cities the knobs on each hydrant are painted different colors to indicate the pressure each hydrant is under. Green knobs indicate a pressure over 120 pounds per square inch (psi); orange knobs indicate a pressure of 50-120 psi; red knobs indicate the lowest pressure at <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 into other resources if need be. The color-coated hydrants/knobs assist firefighters in their initial assessment of available resources.