That splash of color on top of a fire hydrant is not decoration. It is a code that tells firefighters, in seconds, how much water they can count on before they even hook up a hose. The National Fire Protection Association (NFPA) has a recommended practice for marking hydrants: NFPA 291. Under this standard, caps should be painted one of four colors depending on how many gallons per minute a hydrant can provide. If the hydrant has a light blue cap, its flow is 1,500 gallons per minute or more. A red cap means that the flow is less than 500 gallons per minute, the lowest tier.
Why the color matters more than people think
