How do fire hydrants work?

Question

How is there water "ready to go" at every fire hydrant in the country? What keeps it pressurized? How does this complex system work? Please include links.

Answer 1

Best Answer - Chosen by Voters

Fire hydrants are actually pretty simple in the way they work. Each fire hydrant is connected to a large underground pipe that carries water. To get water out of the hydrant, firefighters use a five-sided wrench to open up one or more of the covers and connect hoses to the openings, which are like the spigots on your faucets at home. Then, they use the same wrench to turn the 'stem nut', which is like your faucet's cold or hot water knobs. Water comes up through the pipe, through the openings, and into the hoses that lead to the fire engines.


The water that comes out of the hydrant is the same water that comes into homes, businesses, and schools. This water has a water pressure of about 50-80 psi (pounds per square inch). This pressure is high enough for everyday use, but is not high enough for use by firefighters. So, the pumps on the fire engines increase the pressure. Then, there are smaller hoses that attach to the engines that firefighters use to fight fires.


Fire hydrants in the cooler states have an added level of complexity because the temperature often goes below freezing in the winter. Since water expands when it freezes and turns to ice, the hydrant could crack if there is water in the hydrant when it freezes and expands. Also, if there was a fire during the freezing weather, the hydrants wouldn't work, because there would be a huge chuck of ice clogging the hydrant.


To avoid the problem of freezing water, many hydrants are 'dry barrel hydrants', which means that no water stays in the upper section of the hydrant when the hydrant valve is turned off. The valve that controls the water flow is below ground and there is a long rod that connects the stem nut to the valve. Next to the valve, there is a drain hole to let water drain out of the barrel of the hydrant after firefighters turn the valve off. The pipe that holds the water is buried deep enough so that it never freezes. (A bit of trivia: Because of this mechanism, it's near impossible for a car to run over a fire hydrant and cause it to gush water as they do in the movies, since there usually is no water in the upper part of the barrel.)


The main challenges of hydrant design --- anti-freezing, hydraulic efficiency, ease of repair --- were all known and dealt with, to varying degrees of success, early on, before 1900. The first steamer or pumper outlet came about around 1860 following the invention of the steam fire engine. Although materials have improved and some of the elements of hydrant design have been refined, the basic form of both the dry barrel and wet barrel hydrants have endured relatively unchanged since the mid 1800s.

note:
The second link gives a facinating account of the history of the fire hydrant.

Source(s):

http://www.ccmr.cornell.edu/education/as…

http://www.firehydrant.org/pictures/hydr…

Answer 2

It's the same as your faucet, they are always pressurized, removing the valve causes the water to flow.

Source(s):

http://www.ccmr.cornell.edu/education/as…

Answer 3

its real complicated but all cities have pumps that hold pressure and deliver water

Answer 4

Them thar big things..... them be water towers.... and all that water up there.... wants to come down here..... and that pull of gravity on all those gallons of water makes a lot of pressure.... so when you open a valve..... guess what?

Answer 5

It's a static water pressure system. If you turn on one or two the system maintains pressue, but if you turned on all the hydrants in a town or city they would have no pressure.

They use the same system as single family homes and businesses, they simply have no pressure reducers on the tap and a larger tap diameter.

Answer 6

Fire hydrants are actually pretty simple in the way they work. Each fire hydrant is connected to a large underground pipe that carries water. To get water out of the hydrant, firefighters use a five-sided wrench to open up one or more of the covers and connect hoses to the openings, which are like the spigots on your faucets at home. Then, they use the same wrench to turn the 'stem nut', which is like your faucet's cold or hot water knobs. Water comes up through the pipe, through the openings, and into the hoses that lead to the fire engines.


The water that comes out of the hydrant is the same water that comes into homes, businesses, and schools. This water has a water pressure of about 50-80 psi (pounds per square inch). This pressure is high enough for everyday use, but is not high enough for use by firefighters. So, the pumps on the fire engines increase the pressure. Then, there are smaller hoses that attach to the engines that firefighters use to fight fires.


Fire hydrants in the cooler states have an added level of complexity because the temperature often goes below freezing in the winter. Since water expands when it freezes and turns to ice, the hydrant could crack if there is water in the hydrant when it freezes and expands. Also, if there was a fire during the freezing weather, the hydrants wouldn't work, because there would be a huge chuck of ice clogging the hydrant.


To avoid the problem of freezing water, many hydrants are 'dry barrel hydrants', which means that no water stays in the upper section of the hydrant when the hydrant valve is turned off. The valve that controls the water flow is below ground and there is a long rod that connects the stem nut to the valve. Next to the valve, there is a drain hole to let water drain out of the barrel of the hydrant after firefighters turn the valve off. The pipe that holds the water is buried deep enough so that it never freezes. (A bit of trivia: Because of this mechanism, it's near impossible for a car to run over a fire hydrant and cause it to gush water as they do in the movies, since there usually is no water in the upper part of the barrel.)






THIS LINK GIVES YOU THE HISTORY OF THE FIRE HYDRATE , FROM THE FIRST ONE MADE TO THE LAST ONE THAT EXIST NOW!
http://www.firehydrant.org/pictures/hydr…

Source(s):

Hold on for the link!!! I guess the above person already got it before I got through!
http://www.ccmr.cornell.edu/education/as…

Answer 7

Inventive Ingenuity: Father of the Fire Hydrant
Posted February 22nd, 2007 by Mike Daisy

Do you know anything about Birdsill Holly? He's an important inventor that invented something used to save millions of lives a year.

Michael Daisy, our Guest Blogger, is a freelance writer and publicist. He is also a history fan (or buff), and music fan currently working on an aural documentary of popular music in the U.S. from 1940-2000. He wanted to share his knowledge of the inventors and inventions that have touched our lives with the readers of AmericanInventorSpot.com.

Here's his article:

* * * * *

Who invented the fire hydrant?

If you said, "Birdsill Holly," go to the head of the class. On the other hand, you're not alone if you didn't know, and muttered something like, "Huh?" when you saw the name.

You might expect someone with a name like Birdsill (Birdsill Jr., to be precise) would be remembered for the name alone, if not for his prodigious contributions to the field of hydraulic engineering in the 19th Century. Then again, you might expect the recipient of 150 patents - topped only by Thomas Edison's 1,093 - would live on as a mythic piece of Americana next to George Washington's dentures, and Ben Franklin's lightning rod.

So much for clichés about inventing better mousetraps, fame and fortune and all of that. Still, Holly and Edison were friends. Edison even tried to entice Holly to come work for him at Menlo Park.

While Holly was only one of many involved in the development of the fire hydrant, innovations he introduced are largely responsible for the fire hydrant we take for granted today.

Beginnings
Birdsill Holly Jr. was born on November 8, 1820 to Birdsill and Comfort Holly in Auburn, New York. Young Holly's penchant for mechanics came from his father, a millwright and mechanic.

Birdsill, Sr. moved his young family to the area to take part in construction of the new Auburn correctional prison facility. When that job ended he found work on the construction of the Auburn Theological Seminary. When that job ended, however, jobs became scarce, and he tried his hand at farming for a spell.

When young Holly was four the family moved to Seneca Falls, New York, a major center of water-powered industry at the time. It's believed his father worked as a mechanic in one of the town's many mills. When he died in 1828 at the age of 37, young Birdsill, with only a third-grade education, dropped out of school to support his family.

Holly became an apprentice in a cabinet-making shop, and after that a machine shop. Details of his life between 1836 and 1845 are unclear, but it's believed he owned a machine shop in or around Uniontown, PA.

In 1845, Holly became a partner in the Silsby Company, a manufacturer of hydraulic machines and steam-powered fire engines. While there in 1849 he received his first patent, for a rotary water pump. In 1855, he invented the Silsby steam fire engine.

By 1859 Holly's pump designs and ingenuity were attracting attention from influential and moneyed individuals. He relocated to Lockport, New York when Washington Hunt, a future governor, and Thomas Flagler offered to set him up in business. Holly Manufacturing was born. At its peak, the company employed over 500 workers.

At Holly Manufacturing, he designed machinery for the Lockport water works that allowed water to be pumped under pressure into city mains without a reservoir. Shortly thereafter, Holly came up with his first design for a fire hydrant, a device invented before he was born.

Holly's Fire Protection and Water System - an integrated system designed to deliver water under a steady pressure for public safety - brought him worldwide fame in 1863. The system was widely adapted throughout the United States and Canada, and established the standard upon which all current, water distribution systems as based.

In 1869, Holly was issued a patent, number 94749, for an "improved fire hydrant".
Ironically, Chicago declined to purchase the system. That was, however, before Mrs. O'Leary's cow. Shortly after being devastated by the Great Fire of 1871, the City of the Big Shoulders bought into the system that many believed would have kept the fire from raging out of control.

During this productive period of his professional life, Holly divorced his wife, Elizabeth, and married his ward, Sophia, a woman 28 years his junior. The faux pas may have been the seed from which sprouted Holly's historical obscurity. Respectable people in polite Victorian society simply did not get divorced in those days. And they didn't do so in favor of hooking up with trophy wives. Who knows what people would have said about Woody Allen.

Reaching for the Sky
In 1876, Holly's name should have become synonymous with the word, skyscraper. Should have.

Holly drew up plans for a 700-foot-tall structure to be used as an observation tower on Goat Island, located in the middle of the Niagara River between Niagara Falls' Bridal Veil and Horseshoe Falls. The notion of the Falls as a tourist Mecca was considered far fetched at the time. Peter Porter, the island's owner rejected the structure as he did all development proposals that would alter the island's natural state. In fact, he had already turned down advances from P.T. Barnum.

Undeterred, Holly took his skyscraper idea to New York City, which was quickly running out of available space to expand horizontally. Why not built up, instead?

It's a notion that makes perfect sense today, but Holly was ridiculed as a lunatic "farmer from the west," and laughed out of town. Less than a decade later William Jenney built the world's first skyscraper, the Home Insurance Building in Chicago. Its 10 stories were about half the height of Holly's proposed structure.

Citizens in the big city were not about to be upstaged, and Holly could only sit and watch as Chicago and New York engaged in a fevered tug-o-war competition for possession of the world's tallest building based on a succession of designs by just about everyone but Holly.

A Fitting End to an Impressive Career
Many consider Holly's last major innovation, district heating, to be his greatest. Also less commonly known as teleheating, the origins of district heating can be tracked back to the heated baths of ancient Rome. Of the 150 patents issued to Holly, 50 of them were related to steam heating.

The concept involved the distribution of heat, produced at a central location, to distant locations (some of them many miles distant) by means of underground pipes. The system relied on considerable infrastructure (boiler plant, pumps, and mains) for support, but eliminated the need for large equipment expenditures in buildings connected to the system.

To prove the practicality of his system and attract investors, Holly arranged for a demonstration at his home. He constructed a boiler in his basement. Seven-hundred-feet of pipe were looped around his backyard to prove heat could be transmitted over long distances. The pipe terminated in the living quarters of Holly's home.

When the valves were opened, the system worked perfectly, heating the home in a matter of minutes.

A flood of investors soon followed, and the Holly Steam Combination Company was established in 1877. System usage was tracked by metering the amount of steam used by individual customers.

The system was established in a number of cities throughout the United States, a few of which are still in use. In 1985, the American Society of Mechanical Engineers designated the Detroit Edison District Heating System in Downtown Detroit a National Historic Mechanical Engineering Landmark.

At about 7 p.m. on April 27, 1894 following a long illness, Birdsill Holly died at his home. About six-and-one-half hours later, a major portion of the nearby town of Gasport burned to the ground. Gasport didn't buy Holly's fire protection system.

Micheal Daisy
Guest Blogger
AmericanInventorSpot.com

Sources:

American Society of Mechanical Engineers (ASME)
Angelfire.com
City of Lockport, NY
Public Broadcasting System
Steam Traction magazine ["Birdsill Holly: A Biography", November 1988]
U.S. Patent Office
University of Rochester, NY
Wikipedia

Photo Credits: LockportCave.com

Source(s):

Micheal Daisy
Guest Blogger
AmericanInventorSpot.com

Sources:

American Society of Mechanical Engineers (ASME)
Angelfire.com
City of Lockport, NY
Public Broadcasting System
Steam Traction magazine ["Birdsill Holly: A Biography", November 1988]
U.S. Patent Office
University of Rochester, NY
Wikipedia

Photo Credits: LockportCave.com

Answer 8

A hose is attached to the fire hydrant, then the valve is opened to provide a powerful source of water, on the order of 350 kPa (50 lbf/in²) (this pressure varies according to region and depends on various factors including the size and location of the attached water main). This hose can be further attached to a fire engine, which can then use a powerful pump to boost the water pressure and possibly split it into multiple streams. The hose may be connected with a threaded connection or a Storz connector. Care should be taken not to open or close a fire hydrant too quickly, as this can create a water hammer which can damage nearby pipes and equipment. The water inside a charged hoseline causes it to be very heavy and high water pressure causes it to be stiff and unable to make a tight turn while pressurized. When a fire hydrant is unobstructed, this is not a problem, as there is enough room to adequately position the hose.


Clapper valveMost fire hydrant valves are not designed to throttle the water flow; they are designed to be operated full-on or full-off. The valving arrangement of most dry-barrel hydrants is for the drain valve to be open at anything other than full operation. Usage at partial-opening can consequently result in considerable flow directly into the soil surrounding the hydrant, which, over time, can cause severe scouring . A hose with a closed nozzle valve, or fire truck connection, or closed gate valve is always attached to the hydrant prior to opening the hydrant's main valve.

When a Firefighter is operating a hydrant, appropriate Personal protective equipment, such as gloves and a helmet with face shield, are typically worn. High pressure water coursing through a potentially aging and corroding hydrant could cause a failure, injuring the firefighter operating the hydrant or bystanders.


Chicago police car parked illegally in front of a fire hydrant. Note the yellow line on the curb by the hydrant.In most jurisdictions it is illegal to park a car within a certain distance of a fire hydrant. In North America the distances are commonly 3 to 5 m or 10 to 15 ft, often indicated by yellow or red paint on the curb. In the UK, yellow lines are used to keep cars from parking over underground hydrants. Parking restrictions are sometimes ignored (especially in cities where available street parking is scarce), however these laws are usually enforced. The rationale is that hydrants need to be visible and accessible in an emergency.

Source(s):

http://en.wikipedia.org/wiki/Fire_Hydran…

Answer 9

I have seen one nearby that looked kinda like a brewery with the big ol tanks, but it pressurizred and said it was highly dangerous

Answer 10

fire hydrants are placed on pressurised water main pipes undeground and are placed in convenient spots for fire brigades to gain access in built up areas at suitable distances from each other. the water main pressure is kept up via pumps. the covers on hydrants are clearly marked to save confusion with other services. when a hydrant needs to be used it can be opened by way of a large metal key and a special reinforced hose can be connected and the pressure will drive water through this hose to the area that requires the water,usually a fire. when the operation is over the same key will turn off the hydrant and the hose can be disconnected.

Source(s):

i fit hydrants to water mains that i install along with meters and valves which have their own important uses.