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For other uses, see Manhole (disambiguation).
PMG manholes in a city street, Perth, Western Australia.
Manhole in Belo Horizonte, Brazil.
This is a sewer manhole, exposed during construction. Typically, only the top ring and manhole cover (not pictured) would be visible.
Manhole cover of precast concrete in Germany

A manhole (alternatively utility hole, cable chamber, maintenance hole, inspection chamber, access chamber, sewer hole or confined space) is the top opening to an underground utility vault used to house an access point for making connections, inspection, valve adjustments or performing maintenance on underground and buried public utility and other services including sewers, telephone, electricity, storm drains, district heating and gas.

Usage[edit]

Manhole closings are protected by a manhole cover, a flat plug designed to prevent accidental or unauthorized access to the manhole. Those plugs are traditionally made of metal, but may be constructed from precast concrete, glass reinforced plastic or other composite material (especially in Europe, or where cover theft is of concern).

Manholes are usually outfitted with metal, polypropylene, or fiberglass steps installed in the inner side of the wall to allow easy descent into the utility space. Because of legislation restricting acceptable manual handling weights, Europe has seen a move toward lighter weight composite manhole cover materials, which also have the benefits of greater slip resistance and electrical insulating properties.

The access openings are usually circular in shape to prevent accidental fall of the cover into the hole.

Manholes are generally found in urban areas, in streets and occasionally under sidewalks. In rural and undeveloped areas, services such as telephone and electricity are usually carried on utility poles or even pylons rather than underground.

Composite manholes[edit]

Composite (fiberglass) manholes are commonly used in applications where infiltration, exfiltration, or corrosion by hydrogen sulfide (from sewer gas) are a concern, or where structures need to be factory integrated into a manhole before placement.

Structures commonly integrated into composite manholes include:

  • Flow inverts[1]
  • Flumes[2]
  • Drop structures from higher elevation flows to lower elevation discharge pipes

Occasionally, composite manholes will integrate:

  • Weirs[3]
  • Storm water screening structures[4]
  • Sewage grinders[5]
  • Energy absorbing structures to dissipate undesirable flow stream turbulence or velocity[6]

Hazards caused by stray voltage in manholes[edit]

In urban areas, stray voltage issues have become a significant concern for utilities. In 2004, Jodie S. Lane was electrocuted after stepping on a metal manhole cover, while walking her dog in New York City.[7]

See also[edit]

Notes[edit]

References[edit]

  • Isles, Paul (2010). "Dover Engineering Works". Dover Life Magazine

Further reading[edit]

  • Ascher, Kate ; researched by Wendy Marech (2007). The works : anatomy of a city (Reprint. ed.). New York: Penguin Press. ISBN 978-0143112709. 

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Manhole — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.

30265 news items

NBCNews.com

NBCNews.com
Wed, 19 Aug 2015 02:00:00 -0700

It wasn't a bird, a plane or Superman that blasted nearly 200 feet into the sky in Buffalo, New York, in April. It was a manhole cover. Triggered by an underground electrical fire that ignited some volatile gasses, the manhole cover shot into the sky ...

Arizona Daily Star (blog)

Tucson News Now
Thu, 20 Aug 2015 08:25:58 -0700

For the fourth time in eight months, metal spikes have been found in manhole covers on the east side of Tucson. So far at least 32 vehicles have been damaged by the spikes, which have been placed by unknown individuals. Luckily, the damage has been ...

The New Indian Express

The New Indian Express
Tue, 25 Aug 2015 16:15:00 -0700

QUEEN'S ROAD: The death of two workers in a manhole last week exposes the callous disregard of scavenging rules. Yathiraj and Prasanna were called to unclog a drain in one of the homes at the Income Tax quarters in Jayamahal. They realised the drain ...
 
The Hindu
Wed, 26 Aug 2015 17:04:02 -0700

With no compensation having reached the families of the two workers, who lost their lives while cleaning a clogged manhole last week, the National Safai Karmachari Commission has set a deadline of August 28. Prasanna and Sethu suffocated while ...

Indianapolis Star

Indianapolis Star
Fri, 21 Aug 2015 02:00:00 -0700

The state agency that represents utility customers has cited the manhole blasts in its argument to state utility regulators that IPL doesn't deserve its requested rate hike of 5.6 percent, or $68 million a year. The jump in rates would affect 470,000 ...
 
The Guardian
Fri, 31 Jul 2015 01:54:25 -0700

Drain covers mark the entrances to underground tunnels and shafts that shift utilities around the urban environment. While most are plain and functional, many cities add a touch of local flair to brighten up the streets beneath our feet ...

Daily Mail

Daily Mail
Sat, 15 Aug 2015 15:47:07 -0700

New Yorkers ran for cover as manhole covers rained down on a busy city street on Friday at lunch time when three manholes exploded into a fiery flame just feet from each other. The explosions all rocked the corner of 45th and 9th Avenue on Manhattan's ...

NBC New York

NBC New York
Thu, 06 Aug 2015 13:16:55 -0700

A manhole exploded underneath an occupied New York City MTA bus, sending the nearly 300-pound iron plate cover up through the floor of the bus and hitting a passenger sitting on the bus Tuesday. Brynn Gingras reports (Published Thursday, Aug. 6, 2015).
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