![Kolektory Praha, 14](https://upload.wikimedia.org/wikipedia/commons/e/ee/Kolektory_Praha%2C_14.jpg)
A utility tunnel, utility corridor, or utilidor is a passage built underground or above ground to carry utility lines such as electricity,
steam
Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...
, water supply pipes, and sewer pipes. Communications utilities like
fiber optics
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...
,
cable television
Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broa ...
, and
telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...
cables are also sometimes carried. One may also be referred to as a services tunnel, services trench, services vault, or cable vault. Smaller cable containment is often referred to as a cable duct or underground conduit.
Direct-buried cable
Direct-buried cable (DBC) is a kind of communications or transmissions electrical cable which is especially designed to be buried under the ground without any other cover, sheath, or duct to protect it.
Most direct-buried cable is built to spec ...
is a major alternative to ducts or tunnels.
Usage
Utility tunnels are common in very cold climates where direct burial below the
frost line
The frost line—also known as frost depth or freezing depth—is most commonly the depth to which the groundwater in soil is expected to freeze. The frost depth depends on the climatic conditions of an area, the heat transfer properties of the s ...
is not feasible (such as in
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
, where the frost line is often more than below the surface, which is
frozen year round). They are also built in places where the
water table
The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated.
T ...
is too high to bury water and sewer mains, and where
utility pole
A utility pole is a column or post typically made out of wood used to support overhead power lines and various other public utilities, such as electrical cable, optical fiber, fiber optic cable, and related equipment such as Distribution transfor ...
s would be too unsightly or pose a danger (like in
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
prone
Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
). Tunnels are also built to avoid the disruption caused by recurring construction, repair and upgrading of cables and pipes in direct burial trenches.
Utility tunnels are also often common on large industrial, institutional, or commercial sites, where multiple large-scale services infrastructure (gas, water, power, heat, steam, compressed air, telecommunications cable, etc.) are distributed around the site to multiple buildings, without impeding vehicular or pedestrian traffic above ground. Due to the nature of these services, they may require regular inspection, repair, maintenance, or replacement, and therefore accessible utility tunnels are preferred instead of direct burying of the services in the ground.
Utility tunnels range in size from just large enough to accommodate the utility being carried, to very large tunnels that can also accommodate human and even vehicular traffic.
Confined Space
Some utility tunnels can be a
Confined space
A confined space is a space with limited entry and egress and not suitable for human inhabitants. An example is the interior of a storage tank, occasionally entered by maintenance workers but not intended for human occupancy. Hazards in a confined ...
.
According to the OSHA, a permit-required confined space (permit space) has the three characteristics listed above (which define a confined space) and one or more of the following:
# Contains or has the potential to contain a hazardous atmosphere
# Contains a material that has the potential for engulfing the entrant
# Has an internal configuration that might cause an entrant to be trapped or
asphyxia
Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. There are many circumstances that can i ...
ted by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross section
# Contains any other recognized serious safety or health hazards.
Industrial, institutional, and municipal environments
Utility tunnels are often installed in large industrial plants, as well as large institutions, such as universities, hospitals, research labs, and other facilities managed in common. Shared facilities, such as
district heating
District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating a ...
, use
superheated steam
Superheated steam is steam at a temperature higher than its vaporization point at the absolute pressure where the temperature is measured.
Superheated steam can therefore cool (lose internal energy) by some amount, resulting in a lowering of its ...
pipes routed through utility tunnels. On some university campuses, such as the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
, many of the buildings are connected via large underground passages to allow easy movement of people and equipment.
Some municipalities, such as
Prague
Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 million people. The city has a temperate ...
in the
Czech Republic
The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...
, have installed extensive underground utility tunnels, to allow installation and maintenance of utility lines and equipment without disrupting the historic streets above.
Utility tunnels may attract
urban explorers
Urban exploration (often shortened as UE, urbex and sometimes known as roof and tunnel hacking) is the exploration of manmade structures, usually abandoned ruins or hidden components of the manmade environment. Photography and historical inter ...
, who enjoy investigating hidden complex networks of spaces.
At Walt Disney World
Some of the largest and most famous utility tunnels are at
Disney
The Walt Disney Company, commonly known as Disney (), is an American multinational mass media and entertainment conglomerate headquartered at the Walt Disney Studios complex in Burbank, California. Disney was originally founded on October ...
theme park
An amusement park is a park that features various attractions, such as rides and games, as well as other events for entertainment purposes. A theme park is a type of amusement park that bases its structures and attractions around a central ...
s. They were first built for
Walt Disney World
The Walt Disney World Resort, also called Walt Disney World or Disney World, is an entertainment resort complex in Bay Lake and Lake Buena Vista, Florida, United States, near the cities of Orlando and Kissimmee. Opened on October 1, 1971, th ...
's
Magic Kingdom
Magic Kingdom Park, previously known as Walt Disney World Magic Kingdom (1971–1994) and The Magic Kingdom (1994–2017), is a theme park at the Walt Disney World Resort in Bay Lake, Florida, near Orlando, Florida. Owned and operated by The W ...
in
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
. Smaller utilidor systems are built under the central section of
Epcot
Epcot, stylized in all uppercase as EPCOT, is a theme park at the Walt Disney World Resort in Bay Lake, Florida. It is owned and operated by The Walt Disney Company through its Parks, Experiences and Products division. Inspired by an unreal ...
's Future World, primarily beneath
Spaceship Earth and
Innoventions, and formerly at
Pleasure Island.
Disneyland
Disneyland is a amusement park, theme park in Anaheim, California. Opened in 1955, it was the first theme park opened by The Walt Disney Company and the only one designed and constructed under the direct supervision of Walt Disney. Disney in ...
also has a small utilidor through
Tomorrowland
Tomorrowland is one of the many themed lands featured at all of the Magic Kingdom styled Disney theme parks around the world owned or licensed by The Walt Disney Company. Each version of the land is different and features numerous attractions t ...
. The utilidors are a part of Disney's "backstage" (behind-the-scenes) area. They allow Disney employees ("cast members") to perform park support operations, such as trash removal, out of the sight of guests.
Arctic towns
![FlinFlon Stack](https://upload.wikimedia.org/wikipedia/commons/e/e6/FlinFlon_Stack.jpg)
Utilidors are above-ground enclosed utility conduits that are used in larger communities in the northern polar region where
permafrost
Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...
does not allow the normal practice of burying water and sewer pipes underground. They can in particular be found in
Inuvik
Inuvik (''place of man'') is the only town in the Inuvik Region, and the third largest community in Canada's Northwest Territories. Located in what is sometimes called the Beaufort Delta Region, it serves as its administrative and service cen ...
, Northwest Territories and
Iqaluit
Iqaluit ( ; , ; ) is the capital of the Canadian territory of Nunavut, its largest community, and its only city. It was known as Frobisher Bay from 1942 to 1987, after the large bay on the coast on which the city is situated. In 1987, its t ...
, Nunavut. Not all older homes are connected, and these must rely on trucks to deliver water and remove sewage. Most homes in rural Alaska (off the road system) are not equipped with plumbing and require fresh water and waste to be transported by personal vehicle such as
snowmobile
A snowmobile, also known as a Ski-Doo, snowmachine, sled, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow. It is designed to be operated on snow and ice and does not ...
or
four-wheeler ATV. Villages with utilidors are considered more advanced.
Utilidors may also be used to carry fuel lines, such as natural gas. They are not normally used to carry wiring for electric, telephone, and television service, which are usually suspended from poles.
Comparison with direct burial of utilities
The advantages of utility tunnels are the reduction of maintenance
manhole
A manhole (utility hole, maintenance hole, or sewer hole) is an opening to a confined space such as a shaft, utility vault, or large vessel. Manholes are often used as an access point for an underground public utility, allowing inspection, m ...
s, one-time relocation, and less
excavation and repair, compared to separate cable ducts for each service. When they are well mapped, they also allow rapid access to all utilities without having to dig access trenches or resort to confused and often inaccurate utility maps.
One of the greatest advantages is
public safety
Public security or public safety is the prevention of and protection from events that could endanger the safety and security of the public from significant danger, injury, or property damage. It is often conducted by a state government to ensure ...
. Underground
power line
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-p ...
s, whether in common or separate channels, prevent downed utility cables from blocking
road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
s, thus speeding
emergency
An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening ...
access after
natural disaster
A natural disaster is "the negative impact following an actual occurrence of natural hazard in the event that it significantly harms a community". A natural disaster can cause loss of life or damage property, and typically leaves some econ ...
s such as
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
s,
hurricane
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
s, and
tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...
s.
The following table compares the features of utility networks in single purpose buried trenches vs. the features of common ducts or tunnels:
Examples
Many examples of utility tunnels are found in
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
, where government officials have sought ways to reduce the catastrophic effects of earthquakes in their
tectonically active country. Their use, however, is not limited to that country, and there are many examples of such utility tunnels. These include:
* Incorporated with
Xinyi and Sonshan
MRT
MRT may refer to:
Transport Rapid Transit Systems
* Mass Rapid Transit (disambiguation)
* MRT (Singapore) or Mass Rapid Transit, Singapore
* MRT (Bangkok) or Metropolitan Rapid Transit, Thailand
* Manila Metro Rail Transit System, Philippine ...
rapid transit
Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be c ...
lines in
Taipei, Taiwan
Taipei (), officially Taipei City, is the capital and a special municipality of the Republic of China (Taiwan). Located in Northern Taiwan, Taipei City is an enclave of the municipality of New Taipei City that sits about southwest of the ...
.
* Azabu-Hibiya Common Utility Duct in
Tokyo, Japan
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and List of cities in Japan, largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, ...
* Minatomirai District lines in
Yokohama, Japan
is the second-largest city in Japan by population and the most populous municipality of Japan. It is the capital city and the most populous city in Kanagawa Prefecture, with a 2020 population of 3.8 million. It lies on Tokyo Bay, south of To ...
* Portions of the
Chicago Tunnel Company
The Chicago Tunnel Company was the builder and operator of a narrow-gauge railway freight tunnel network under downtown Chicago, Illinois. This was regulated by the Interstate Commerce Commission as an interurban even though it operated entir ...
's abandoned network of tunnels are leased to utility companies for use as
common utility duct
A utility tunnel, utility corridor, or utilidor is a passage built underground or above ground to carry utility lines such as electricity, steam, water supply pipes, and sewer pipes. Communications utilities like fiber optics, cable television ...
s for electrical, communication and HVAC lines. The tunnels lie approximately forty feet below the street surface and run under all streets in the
central business district
A central business district (CBD) is the commercial and business centre of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the "city ...
, except where they were displaced by rapid transit tunnels.
*
Poundbury
Poundbury is an experimental planned community or urban extension on the western outskirts of Dorchester in the county of Dorset, England. The development is led by the Duchy of Cornwall, and had the keen endorsement of King Charles III when h ...
in
Dorset
Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...
, England, a
planned community
A planned community, planned city, planned town, or planned settlement is any community that was carefully planned from its inception and is typically constructed on previously undeveloped land. This contrasts with settlements that evolve ...
built on land belonging to
King Charles as
Duke of Cornwall
Duke of Cornwall is a title in the Peerage of England, traditionally held by the eldest son of the reigning British monarch, previously the English monarch. The duchy of Cornwall was the first duchy created in England and was established by a ro ...
, incorporates common utility ducts
*
Bremen, Germany
Bremen (Low German also: ''Breem'' or ''Bräm''), officially the City Municipality of Bremen (german: Stadtgemeinde Bremen, ), is the capital of the German state Free Hanseatic City of Bremen (''Freie Hansestadt Bremen''), a two-city-state consis ...
has near-perfect surfaces on its footways, cycleways, and streets, with virtually no visible repairs or disturbances. This is achieved by an absence of vehicles on footways or cycleways, and utility ducts that make it is unnecessary to disturb the surfaces in order to access the networks. Utility networks are housed in a cluster of pipes which are located under footways and cycleways.
* The
Dartford Cable Tunnel
The Dartford Cable Tunnel is a 2.4 km utility tunnel beneath the Thames, upstream of the Dartford Crossing. With a diameter of ~, it carries a 400 kV National Grid electrical transmission cable. It is accessible by foot as a crossing of ...
allows high voltage electricity line to cross the
River Thames
The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, se ...
.
* The Utility Tunnels in
Qatar
Qatar (, ; ar, قطر, Qaṭar ; local vernacular pronunciation: ), officially the State of Qatar,) is a country in Western Asia. It occupies the Qatar Peninsula on the northeastern coast of the Arabian Peninsula in the Middle East; it sh ...
built on the
Lusail
Lusail ( ar, لوسيل, , ) is the second-largest city in Qatar, located on the coast, in the southern part of the municipality of Al Daayen. Lusail is located about north of the city centre of Doha, just north of the West Bay Lagoon, on over ...
, 15 km north of Doha, is approximately 14–15 km in length.
* The old
Beacon Hill Tunnel in New Kowloon, Hong Kong, a disused railway tunnel which now carries a towngas pipeline
* Tunnels of
Hongkong Electric
The Hongkong Electric Company (HEC; ) is one of Hong Kong's two main electricity generation companies, the other being CLP Group, China Light & Power. The company is owned by several companies including Power Assets Holdings, State Grid Corporat ...
* Utility Tunnel in
GIFT City
Gujarat International Finance Tec-City (GIFT City) is central business district under-construction in Gandhinagar and Ahmedabad in Gandhinagar district in Gujarat, India. It is India's first operational greenfield smart city and international ...
,
Gandhinagar
Gandhinagar (, ) is the capital of the state of Gujarat in India. Gandhinagar is located approximately 23 km north of Ahmedabad, on the west central point of the Industrial corridor between Delhi, the political capital of India, and Mu ...
,
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
"Gujarat International Finance Tec-city: A Smart GIFT"
/ref>
Gallery
File:Schiffbau tunnel.jpg, Stark utility tunnel in Zurich, Switzerland
File:Fernwärmetunnel Köln (2).jpg, District heating
District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating a ...
tunnel beneath the Rhein River
), Surselva, Graubünden, Switzerland
, source1_coordinates=
, source1_elevation =
, source2 = Rein Posteriur/Hinterrhein
, source2_location = Paradies Glacier, Graubünden, Switzerland
, source2_coordinates=
, source ...
in Cologne, Germany
Cologne ( ; german: Köln ; ksh, Kölle ) is the largest city of the German western state of North Rhine-Westphalia (NRW) and the fourth-most populous city of Germany with 1.1 million inhabitants in the city proper and 3.6 million ...
File:Heatpipe tunnel copenhagen 2009.jpg, District heating tunnel in Copenhagen, Denmark
Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...
File:Utility tunnel.jpg, Red arrow marks a prefabricated element of a utility tunnel already placed in the trench
File:Haifa Utility tunnel.JPG, A newly built utility tunnel in Haifa, Israel
Haifa ( he, חֵיפָה ' ; ar, حَيْفَا ') is the third-largest city in Israel—after Jerusalem and Tel Aviv—with a population of in . The city of Haifa forms part of the Haifa metropolitan area, the third-most populous metropol ...
File:Kolektory Praha, 48.jpg, Tunnel in Prague
Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 million people. The city has a temperate ...
is shared by pipes and cables
File:Interior view of utilidor passageway link between building nos. 101 and 102 showing waveguides on left and cable tray system on right sides. Note fire suppression water supply piping HAER AK-30-A-102.tif, Utility passageway between two buildings of a Ballistic Missile Early Warning System
The RCA 474L Ballistic Missile Early Warning System (BMEWS, "474L System", Project 474L) was a United States Air Force Cold War early warning radar, computer, and communications system, for ballistic missile detection. The network of twelve ra ...
site in Alaska.
File:Connecting-houses.jpg, Utilidors connecting houses in Inuvik
Inuvik (''place of man'') is the only town in the Inuvik Region, and the third largest community in Canada's Northwest Territories. Located in what is sometimes called the Beaufort Delta Region, it serves as its administrative and service cen ...
, Northwest Territories, Canada
The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
File:Utility Tunnel GIFT City.jpg, Utility Tunnel in GIFT City
Gujarat International Finance Tec-City (GIFT City) is central business district under-construction in Gandhinagar and Ahmedabad in Gandhinagar district in Gujarat, India. It is India's first operational greenfield smart city and international ...
Gandhinagar
Gandhinagar (, ) is the capital of the state of Gujarat in India. Gandhinagar is located approximately 23 km north of Ahmedabad, on the west central point of the Industrial corridor between Delhi, the political capital of India, and Mu ...
, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
File:Barrow High School 2007-12-08.jpg, A utilidor system is used in Utqiaġvik, Alaska
Utqiagvik ( ik, Utqiaġvik; , , formerly known as Barrow ()) is the borough seat and largest city of the North Slope Borough, Alaska, North Slope Borough in the U.S. state of Alaska. Located north of the Arctic Circle, it is one of the List of ...
due to extensive permafrost
Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...
underlying the city. At right foreground is a portion of the utilidor crossing Okpik Street overhead, adjacent to Barrow High School
Barrow High School is a public high school in Utqiaġvik (formerly Barrow), Alaska, United States, operated by the North Slope Borough School District. As of the 2016–2017 school year, the school had 232 students.
Athletics
Football
A high ...
.
See also
*Dartford Cable Tunnel
The Dartford Cable Tunnel is a 2.4 km utility tunnel beneath the Thames, upstream of the Dartford Crossing. With a diameter of ~, it carries a 400 kV National Grid electrical transmission cable. It is accessible by foot as a crossing of ...
*Tunnel
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube cons ...
*Underground city
An underground city is a series of linked subterranean spaces that may provide a defensive refuge; a place for living, working or shopping; a transit system; mausolea; wine or storage cellars; cisterns or drainage channels; or several of thes ...
*Utility vault
A utility vault is an underground room providing access to subterranean public utility equipment, such as valves for water or natural gas pipes, or switchgear for electrical or telecommunications equipment. A vault is often accessible directly fro ...
References
{{Authority control
Tunnels
Subterranea (geography)