Strange symbol of New York: why steam is pouring out of the ground in the city

In almost every movie about new york two attributes remain unchanged: yellow taxis and a thick gaseous eruption from white-orange pipes. It stretches from Battery Park to 96th Street, says New york gid.

This eruption is not only an important cultural code of the city, but also the result of a unique steam system.

The Big Apple's steam service system stretches for nearly 170 kilometers, consists of 3000 wells and supplies steam to about 1800 buildings - from the Empire State Building and Rockefeller Center to the Metropolitan Museum of Art and UN headquarters.

Urban steam service is the first of such a large scale system. They are extremely rare in cities.

Century history

A century ago, engineers decided that steam could heat buildings. If this idea succeeded, it would no longer be necessary to deliver coal, remove ash. There would be no need to hire teams of workers. No plethora of stoves, and the air outside would be cleaner.

And on May 3, 1882, the idea was carried out. The first building where steam was supplied was located 800 meters from the boiler room. The building was located at 88 Broadway and was supplied by the New York Steam Company.

By the end of that year, the New York Steam Company was servicing 62 buildings. Very soon the system began to expand. Pipes were laid from lower Manhattan all the way to Harlem. Steam began to be used to operate laundries, dry cleaners, to sterilize hospital equipment and to operate various steam units.

Con edison

Today, steam generation and piping, as well as steam system maintenance, are provided by one of America's largest energy companies, Con Edison.

More than half of this steam is used to heat, cool and supply 2000 buildings in the city. Part of the steam is created on purpose, part of it is a "waste" by-product of electricity generation.

How the New York City Steam System Works

Everyone knows the law of physics: when water is heated to a boil, it turns into steam. The same is true for Cohn Edison boilers.

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When generating electricity at its power plants, the company uses gas to heat water in boilers to a temperature of 537 degrees Celsius under a pressure of 16,5 megapascals. When released outside, the steam turns hundreds of turbine blades that rotate generators at a tremendous speed, and creates electricity. Part of the steam is cooled, condensed and turned into hot water, after which it is reused.

The rest of the steam exits the generator, its pressure and temperature drop, and it is fed directly into pipes and lines under the streets of Manhattan.

Today the temperature of this steam is about 196 degrees Celsius, and the pressure is just over 1 megapascal. Steam moves through pipes for a distance of up to 120 kilometers. It heats buildings, runs air conditioners and equipment in hotels, factories, apartments and the tallest skyscrapers.

In parts of Manhattan, hot tap water is heated with steam.
What's more, roughly 250 buildings in the Big Apple use this steam for summer cooling. Steam is used in the heating cycle of water chillers.

How the steam ends up in the street

Managing such a huge underground steam network requires a well-established safety valve system. Periodically, a leak is found in any of the manholes. Considering the length of the system and its impressive age, minor breakouts happen quite often.

Rare errors and incidents in the operation of this system are fraught with larger gusts, which can lead to real explosions with serious consequences. The last big unforeseen event happened in 2018 on Fifth Avenue, next to the Iron House. As a result of the explosion, debris of the road surface flew to the roofs of 20-storey buildings. Residents of 40 nearby houses were evacuated for safety reasons. The repair of this section lasted more than a year.

During pipeline repairs, excess steam is released from the safety valves, and it falls into the street. At such moments, you can observe the ubiquitous white-orange pipes, just like in movies... They are installed at the crash site to keep excess steam away from vehicles and pedestrians.

Firstly, this steam is absolutely safe, and secondly, it adds a unique charm to the city. The safety valves are accessed through manholes. They are usually located right on the road.

Repair work

For safe operation on a specific pipeline, the steam supply to this area is shut off.

The pipes are buried underground at a depth of about 0,6 meters, and in some places up to 9 meters. Therefore, the only way to access them is by digging. Often, during repair work, rainwater enters the bare heating main and instantly turns into steam, which in turn begins to ooze out of the ground.

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A broken line can be quickly isolated. To do this, crews go underground to carry out repairs, followed by the installation of new steel pipes and fittings. When the hatches are excavated, old pipe insulation and debris are removed and, to seal the leak again, shutoff valves are closed and defective fittings replaced.

As a rule, the main culprits of the incident are old components, which are made of cast iron a little more than a centimeter thick. They crack easily when exposed to water from external sources. To avoid leaks, they are replaced with steel ones.