What is fire hydrant?
Many of us have the experience of hearing loud horns honking and shrieking of sirens when fire trucks rushed to tackle a blaze. The fire trucks pass by and respond to a nearby office building caught on fire with giant plumes of smoke.
You might start wondering how firefighters do their job and put out the fire with adequate water supply coming from nowhere. Obviously, the fire truck does not have that big a water tank to deliver all the water needed.
How could firefighters get the water as if by magic? As a matter of fact, the firefighters do not pull a rabbit out of a hat because the water source is right in your own neighborhood.
These water supply points around you are rarely noticed by you, or you just take them for grated without giving them a second thought when seeing them. And those magic water supply points all around us are FIRE HYDRANTS we are going to talk about.
The inventor of modern fire hydrant is known to be the then Chief Engineer on the Philadelphia Water Works named Mr. Frederick Graff, Sr. Around 1801, Mr. Graff came up the first post or pillar type of fire hydrants. What he invented was considered a “wet-barrel” design chiefly because the part of the hydrant above the ground had a valve on top of it, thus containing plenty of water.
Fire hydrants are deliberately painted in bright red or yellow to help firefighters locate them easily and swiftly in case of an emergency. Certain colors are added on fire hydrants by local law to specify the amount of water at given pressure that they can supply, so that firefighters will be able to choose the right fire hydrant for specific fire situations.
How do fire hydrant work?
Fire hydrants, also known as fire plugs, look like short, stubby iron cylinders of different sizes and appearances with a variety of valves and connection points. These devices can be seen quite often along the streets and sidewalks.
Known as an active fire protection device, fire hydrants enable firefighters to locate the nearest water supply at the fire scene in a timely manner. The water tank of a fire truck holds enough water only to contain the blaze in the first place before hoses are connected to the properly chosen fire hydrants to put the fire out.
The great advantage of fire hydrants is that they can supply a large volume of water, which is pumped through hoses to the fire truck to get pressurized and then divided into several fire hoses as spontaneous multiple water supplies.
Nowadays, fire hydrants with “dry-barrel” designs, however, are commonly used in cold regions where temperature is below freezing. These types of hydrants have their valves underground below the freeze line. Since no water is in the part above the surface of the ground, the hydrants do not get clogged by frozen water inside that causes ice blockage.