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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.
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29681 news items

 
Tucson News Now
Thu, 21 May 2015 11:19:34 -0700

TUCSON, AZ (Tucson News Now) - Tucson police continue to work the case of the spikes in manhole covers. Someone is putting sharpened bolts into the small holes in the covers, and blowing out tires on passing vehicles. More than a half dozen of these ...

Patch.com

Patch.com
Thu, 21 May 2015 14:51:58 -0700

The petition maintains that Lader was walking south along the shoulder of Harlem Avenue in the northbound lanes between 143rd and 151st streets when he stumbled into the open manhole. He was eventually found in the 14700 block of Harlem Avenue in ...
 
The Denver Post (blog)
Wed, 20 May 2015 15:52:30 -0700

Eighteen months ago I made Colorado my home and I love it here. In the spirit of believing everything has a rationale behind it, I must ask about manhole covers. Why is it they cannot be level with the road? Joan Carr, Aurora. This letter was published ...

Wigan Today

Wigan Today
Thu, 21 May 2015 02:11:15 -0700

Residents today spoke of their relief the noise, which had continued day and night as the main road and access route to the M6 is extremely busy, was over but said they should not have had to go to such lengths to get the manhole cover fixed. Michelle ...

KTLA

KTLA
Fri, 15 May 2015 15:40:21 -0700

An electrical vault explosion caused a steel manhole cover to “dislodge” and fall onto two cars, leaving three people injured in Northridge on Friday, authorities said. Three cars were involved in a crash related to the explosion, and power was ...
 
Quad-Cities Online
Wed, 20 May 2015 20:38:24 -0700

Trustee Dale Keppy noted that Missman estimated new manhole covers to cost $750 each, while Front Range priced them at $250. Mr. Wilson responded that the covers must meet the specifications Missman puts in place. In other news, trustees approved an ...

The Local.ch

The Local.ch
Tue, 19 May 2015 13:29:48 -0700

Emergency medical staff confirmed the man, a Swiss citizen working for an engineering company, was dead and fire fighters retrieved him from the manhole. Police said it quickly became apparent that the man was not the victim of a work accident but of a ...

WAVY-TV

WAVY-TV
Thu, 14 May 2015 07:56:42 -0700

According to the Associate Vice President of Communications and University Relations Brian Whitson, an officer was doing a routine patrol around 2:20 a.m. when he initially saw a student sitting at an open manhole. The investigation revealed six other ...
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