<P> Hydrant coloring may be due to either purely practical criteria or more artistic . In the United States , the AWWA and NFPA recommend hydrants be colored chrome yellow for rapid identification apart from the bonnet and nozzle caps which should be coded according to their available flow . Class AA hydrants ( > 1500 gpm ) should have their nozzle caps and bonnet colored light blue , Class A hydrants ( 1000 -- 1499 gpm ) , green , Class B hydrants ( 500 -- 999 gpm ) , orange , Class C hydrants ( 0 -- 499 gpm ) , red and inoperable or end - of - system ( risking water hammer ) black . This aids arriving firefighters in determining how much water is available and whether to call for additional resources , or find another hydrant . Other codings can be and frequently are used , some of greater complexity , incorporating pressure information , others more simplistic . In Ottawa , Ontario , hydrant colors communicate different messages to firefighters ; for example , if the inside of the hydrant is corroded so much that the interior diameter is too narrow for good pressure , it will be painted in a specific scheme to indicate to firefighters to move on to the next one . In many localities , a white or purple top indicates that the hydrant provides non-potable water . Where artistic and / or aesthetic considerations are paramount , hydrants can be extremely varied , or more subdued . In both instances this is usually at the cost of reduced practicality . </P>
<P> Hydrant coloring may be due to either purely practical criteria or more artistic . In the United States , the AWWA and NFPA recommend hydrants be colored chrome yellow for rapid identification apart from the bonnet and nozzle caps which should be coded according to their available flow . Class AA hydrants ( > 1500 gpm ) should have their nozzle caps and bonnet colored light blue , Class A hydrants ( 1000 -- 1499 gpm ) , green , Class B hydrants ( 500 -- 999 gpm ) , orange , Class C hydrants ( 0 -- 499 gpm ) , red and inoperable or end - of - system ( risking water hammer ) black . This aids arriving firefighters in determining how much water is available and whether to call for additional resources , or find another hydrant . Other codings can be and frequently are used , some of greater complexity , incorporating pressure information , others more simplistic . In Ottawa , Ontario , hydrant colors communicate different messages to firefighters ; for example , if the inside of the hydrant is corroded so much that the interior diameter is too narrow for good pressure , it will be painted in a specific scheme to indicate to firefighters to move on to the next one . In many localities , a white or purple top indicates that the hydrant provides non-potable water . Where artistic and / or aesthetic considerations are paramount , hydrants can be extremely varied , or more subdued . In both instances this is usually at the cost of reduced practicality . </P>
how much water flows through a fire hydrant
how much water flows through a fire hydrant
Class AA hydrants ( > 1500 gpm ) Class A hydrants ( 1000 -- 1499 gpm ) Class B hydrants ( 500 -- 999 gpm ) Class C hydrants ( 0 -- 499 gpm )
Class AA hydrants ( > 1500 gpm ) Class A hydrants ( 1000 -- 1499 gpm ) Class B hydrants ( 500 -- 999 gpm ) Class C hydrants ( 0 -- 499 gpm )