Fun Facts About The Markings And Colors Of Fire Hydrants

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The fire hydrant is one of the many proud symbols behind the fire department. Found throughout most cities, the fire hydrant is well known for being an easy access point for fire fighters to quickly gain access to high-pressure water. The fire hydrant is also known for being a notoriously bad parking spot, as if a fire ever breaks out, fire fighters will not hesitate to tow, damage, or move your car to obtain water access.

However, despite these somewhat common facts, there are many other fun facts regarding fire hydrants, such as why they're colored, that most people don't know. So, if you're interesting learning a bit more about fire hydrants, continue reading as this article will cover some fun and interesting facts regarding how fire hydrants acquired their markings and colors.

Color coding

While nearly everyone can easily recognize a fire hydrant, not everyone knows that each one is color coded for a very specific reason. Fire hydrants are painted with different colors and etchings to help with identification. Fire fighters, and other city officials, by using these various colors and markings, can quickly identify the purpose, output, and limitations of the specific fire hydrants.

Certain regions, like in various municipals of Canada, give their hydrants different colored tops (also known as the bonnet) to help their fire fighters identify the hydrants output capacity (usually measured in liters per second). The United States also color codes their hydrant tops, but measure the output rate in terms of gallons (gallons per minute).

The various colors will let the fire fighters know if they are dealing with a low-pressure, or a high-pressure hydrant. Blue, green, orange, and red are the common colors used by most countries and regions. Red usually represents a low-flowing hydrant. Orange represents a medium flow hydrant. Green represents a high flow hydrant, and blue represents the maximum capacity flowing hydrant.

The outlet cap colors, which can be found on the outward facing extension, are also color coded for identification. These colored arms, which are meant to indicate the PSI output of the valve, are usually the same color as the tops of the hydrant, but can sometimes vary depending on additional markings. Green usually represents over 120 PSI, while orange indicates a range between 50 and 120. Red, the lowest flowing indicators, usually suggests the hydrant be pumped in order to maintain proper flows, as the PSI limit is often 50 or below.

Finally, the hydrant bodies can also be color coded. In regions, such as the United States and Canada, there are 4 basic color codes for the hydrant bodies.

  • Violet - This indicates non-potable water (unsafe for drinking). This water usually originates from a pond, lake, or run-off sources.
  • Yellow - This indicates the hydrant is attached to a public system water main and is intended for private use.
  • White - This indicates the hydrant is intended for public use (local city wide municipal use)
  • Red - This indicates the hydrant is only to be used for special operational use. These hydrants are often related to high-pressure water sources, which require additional safety precautions.

Etchings and markings

Fire hydrants are also known to contain various etchings on them to help fire fighters identify their functions and limitations. The colors used for these etchings are often orange, but can vary by region and local municipal standards. However, regardless of the etching's color, there are 3 standard deviations:

  • Arrow - The arrow indicates the hydrants direction of water flow on a dead end main.
  • Arrow with a vertical stopper - This symbol indicates the direction of water flow, as well as the hydrant being the last one on a dead end main.
  • R surrounded by a circle - This final symbol is meant to indicate that the hydrant is located on a strict pressure regulated zone. The water output is restricted as to not impact other services and water mains.

It is important to note that a dead end main indicates that there is water only originating from one direction. A hydrant that uses all water coming from that one direction (upstream) will deny water from anything afterwards (downstream).

So, while fire hydrants may be easy to recognize and fairly abundant across your city, there is a lot more than what meets the eye. The special color codes of the tops, sides, and bodies of the hydrants can indicate many different functions. The various etchings on hydrants can also provide some useful information. So, next time you see a fire hydrant, you'll be able to accurately tell how it may be used. Contact a company like Terminal City Iron Works Ltd. for more information.