Editing Manhole

{{Short description|Opening to a confined space}}
{{other uses}}
[[File:ManholePMG gobeirne.jpg|thumb|[[Postmaster-General's Department|PMG]] manholes in a city street, [[Perth, Western Australia]]]]
[[File:Working underground.jpg|thumb|[[Sanitary manhole|Manhole]] being used to access sewer]]
[[File:Fiber-Optic Manhole Installation.jpg|thumb|Installation of a fiber-optic manhole in Brooklyn, New York]]
[[File:Uncovered manhole.jpg|thumb|An uncovered manhole in Beirut, Lebanon]]
A '''manhole''' ('''utility hole''', '''maintenance hole''',<ref>{{cite book |last1=Nemerow |first1=Nelson L. |last2=Agardy |first2=Franklin J. |last3=Salvato |first3=Joseph A. |url=https://books.google.com/books?id=VO-Unp1sFAMC |title=Environmental Engineering: Environmental Health and Safety for Municipal Infrastructure, Land Use and Planning, and Industry |edition=6, illustrated |publisher=John Wiley & Sons |date=2009 |isbn=978-0470083055 |access-date=2019-07-19 }}</ref> or '''sewer hole''') is an opening to a [[confined space]] such as a [[shaft (civil engineering)|shaft]], [[utility vault]], or large [[container|vessel]]. Manholes, typically protected by a [[manhole cover]], are often used as an access point for an underground [[public utility]], allowing inspection, maintenance, and system upgrades. The majority of underground services have manholes, including [[Water industry|water]], [[sanitary sewer|sewers]], [[telephone]], [[electricity]], [[storm drain]]s, [[district heating]], and [[natural gas|gas]].

Manholes are generally found in urban areas,<ref name=":0">{{Cite web |last=Singh |first=Kanwarjot |date=2023-06-30 |title=What is a Manhole- Function, Construction, Materials, and Types of Manhole - Civil Engineering Portal |url=https://www.engineeringcivil.com/what-is-a-manhole-function-construction-materials-and-types-of-manhole.html |access-date=2024-04-22 |website=Civil Engineering Portal - Biggest Civil Engineering Information Sharing Website |language=en}}</ref> in streets and occasionally under [[sidewalk]]s. In [[rural]] and undeveloped areas, services such as telephone and electricity are usually carried on [[utility pole]]s or even [[Electricity pylon|pylons]] rather than underground.

In Australia, ''manhole'' also commonly refers to an [[access hatch]] used to get access from a room or hallway into the ceiling cavity of a building.<ref>{{cite web |url=https://training.gov.au/TrainingComponentFiles/CPC/CPCCPB3027_AssessmentRequirements_R1.pdf |title=Assessment Requirements for CPCCPB3027 Install ceiling insulation products |edition=1st |date=17 January 2019 |author=Attribus Innovation |publisher=Commonwealth of Australia |website=Department of Education and Training |access-date=5 July 2019}}</ref><ref>{{cite web |url=https://www.bunnings.com.au/diy-advice/home-improvement/roofing/how-to-install-a-manhole |title=How to install a manhole |website=Bunnings Warehouse |access-date=5 July 2019}}</ref> These manholes are typically around {{cvt|450|x|450|mm|in}} square.

== Construction ==
[[File:Manhole covers in sidewalk (42839905802).jpg|thumb|[[Manhole cover]]s in [[Helsinki]], Finland]]
Manhole closings are protected by a [[grating]] or [[manhole cover]], a flat plug designed to prevent accidental or unauthorized access to the manhole. These covers are traditionally made of metal,<ref name=":0" /> but may be constructed from [[precast concrete]], [[glass reinforced plastic]] or other [[composite material]]s (especially where cover theft is of concern). 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.

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.<ref>{{cite web |url=https://www.ijcaonline.org/research/volume128/number9/bajaj-2015-ijca-906627.pdf |title=Management of Underground Infrastructure |access-date=6 November 2024}}</ref>

Manholes are usually round, primarily because roundness is the best shape to resist the compression of the earth; covers are round because they are easier to move by rolling, and they can't fall into the opening.<ref>{{Cite book |last=Scheckel |first=Larry |url=https://www.google.com/books/edition/Ask_a_Science_Teacher/cpJ-6Jk1rv8C?hl=en&gbpv=1&bsq=manhole |title=Ask a Science Teacher: 250 Answers to Questions You've Always Had About How Everyday Stuff Really Works |date=2013-12-17 |publisher=The Experiment |isbn=978-1-61519-179-6 |language=en}}</ref> But in the United Kingdom they are nearly always square, or rectangular, in shape, at least at street level. Manholes can also be found in a triangular shape (e.g. in [[Cambridge]], and surrounding villages).<ref>{{cite web |title=The ultimate manhole covers site {{!}} Info cover {{!}} Cover's details: Cambridge - Surface water - Cover in a shape close to the triangle (2) |url=https://manhole.co.il/coverDetails.asp?c=7982 |website=manhole.co.il |access-date=13 July 2024}}</ref>

== Composite manholes ==
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. In these manholes, the entire underground enclosure is constructed of some composite material, in addition to the cover.

Structures that can be integrated into composite manholes include:
* Flow inverts<ref name=" Manhole inverts ">{{cite web|url=http://www.containmentsolutions.com/wp-content/uploads/LIT-MAN-Manhole-Brochure.pdf|title=Manhole inverts|publisher=Containment Solutions|access-date=2013-03-07|archive-url=https://web.archive.org/web/20150403115417/http://www.containmentsolutions.com/wp-content/uploads/LIT-MAN-Manhole-Brochure.pdf|archive-date=2015-04-03|url-status=dead}}</ref>
* [[Flume]]s<ref name=" Flow measuring flumes ">{{cite web|url=http://www.openchannelflow.com/products/manholes/flow-monitoring/flumes|title=Packaged Fiberglass (FRP) Flume Manholes|publisher=Openchannelflow|url-status=dead|archive-url=https://web.archive.org/web/20130325002625/http://www.openchannelflow.com/products/manholes/flow-monitoring/flumes/|archive-date=2013-03-25}}</ref>
* Drop structures from higher elevation flows to lower elevation discharge pipes
* [[Weir]]s<ref name="Manhole weirs ">{{cite web|url=http://www.openchannelflow.com/products/manholes/flow-monitoring/weirs/|title=Packaged Fiberglass (FRP) Weir Manholes for Flow Monitoring|publisher=Openchannelflow|url-status=dead|archive-url=https://web.archive.org/web/20130919084241/http://www.openchannelflow.com/products/manholes/flow-monitoring/weirs/|archive-date=2013-09-19}}</ref>
* Storm water screening structures<ref name=" Storm water structures ">{{cite web|url=http://www.openchannelflow.com/products/manholes/storm-water/|title=Fiberglass (FRP) Storm Water Manholes for Initial Oil, Grease, Sediment, and Debris Collection|publisher=Openchannelflow|url-status=dead|archive-url=https://web.archive.org/web/20130307132910/http://openchannelflow.com/products/manholes/storm-water/|archive-date=2013-03-07}}</ref>
* [[Sewage]] grinders<ref name=" Sewage grinders ">{{cite web|url=http://www.openchannelflow.com/products/manholes/grinder/|title=Fiberglass (FRP) Grinder Manholes integrating grinders from JWC, Franklin Miller, MonoFlo, and more|publisher=Openchannelflow|url-status=dead|archive-url=https://web.archive.org/web/20130828234339/http://www.openchannelflow.com/products/manholes/grinder/|archive-date=2013-08-28}}</ref>
* Energy absorbing structures to dissipate undesirable flow stream turbulence or velocity<ref name=" Energy absorbing structures ">{{cite web|url=http://www.openchannelflow.com/products/manholes/energy-absorber/|title=Fiberglass Energy Absorbing Manholes for Controlling Excess Line Velocities|publisher=Openchannelflow|url-status=dead|archive-url=https://web.archive.org/web/20130307131247/http://openchannelflow.com/products/manholes/energy-absorber/|archive-date=2013-03-07}}</ref>

== Hazards caused by manholes ==
In urban areas, damaged or uncovered manholes and [[stray voltage]] issues have become a significant concern. 

On January 16, 2004, Jodie S. Lane was [[electrocution|electrocuted]] after stepping on a metal manhole cover, while walking her two dogs in New York City.<ref>{{cite news|
title=East Village Woman Was Electrocuted on Street With Metal Plate, Medical Examiner Says|url=https://www.nytimes.com/2004/01/19/nyregion/east-village-woman-was-electrocuted-street-with-metal-plate-medical-examiner.html|work=New York Times|first=Anthony |last=Ramirez|date=January 19, 2004|access-date=2009-12-03}}</ref>

On December 3, 2020, Justin Carey, a 49-year-old special education teacher, was injured after stepping on a broken manhole cover on Route 111 in [[Smithtown, New York|Smithtown]]. As he exited his parked car near the Route 347 intersection, the split cover gave way, causing his left leg to fall into the hole. He suffered a strained Achilles tendon and a bruised knee.<ref>{{Cite web |date=2021-05-27 |title=Long Island Man Injured Falling Into Manhole |url=https://888gothurt.com/blog/long-island-man-injured-falling-into-manhole/ |access-date=2025-05-27 |website= |language=en}}</ref>

== Sewer manhole location ==
The location of a sewer manhole must be carefully considered to ensure that the drainage system is effective and easy to [[Maintenance|maintain]].<ref>{{Cite web |date=2023-06-13 |title=Tái diễn tình trạng hố ga mất nắp giữa lòng đô thị thông minh Thái Nguyên |url=https://laodong.vn/photo/tai-dien-tinh-trang-ho-ga-mat-nap-giua-long-do-thi-thong-minh-thai-nguyen-1204218.ldo |access-date=2023-12-20 |website=laodong.vn |language=vi}}</ref><ref>{{Cite web |date=2023-05-30 |title=Cận cảnh vị trí các "lô cốt" sắp lắp đặt trên đường Nguyễn Trãi |url=https://suckhoedoisong.vn/can-canh-cac-vi-tri-lap-dat-rao-chan-thi-cong-tren-duong-nguyen-trai-169230526071706304.htm |access-date=2023-12-20 |website=suckhoedoisong.vn |language=vi}}</ref> According to design standards, the distance between two manholes is typically between 7 and 20 meters, depending on the specific characteristics of the project.<ref>{{Cite web |last=danviet.vn |title=Ám ảnh với hố ga mất nắp, "nuốt trọn" xe máy của người đi đường |url=https://danviet.vn/am-anh-voi-ho-ga-mat-nap-nuot-tron-xe-may-cua-nguoi-di-duong-20231023085139414.htm |access-date=2023-12-20 |website=danviet.vn |date=23 October 2023 |language=vi}}</ref><ref>{{Cite web |title=Đường mới mở và "điệp khúc" mất nắp hố ga |url=https://vovgiaothong.vn/newsaudio/duong-moi-mo-va-diep-khuc-mat-nap-ho-ga-d35444.html |access-date=2023-12-20 |website=vovgiaothong.vn |language=vi}}</ref> In cities, the distance is 20 meters per manhole,<ref>{{Cite book |url=https://books.google.com/books?id=-fjaAAAAMAAJ&q=%22h%E1%BB%91+ga%22+%22gia+%C4%91%C3%ACnh%22 |title=Báo cáo chuyên đề: Mức độ bao phủ của các chương trình y tế công cộng |date=2003 |publisher=Nhà xuất bản Y học |language=vi}}</ref> while in industrial or commercial settings it is 10-15 meters per manhole.<ref>{{Cite book |last=Lê |first=Thành Châu |url=https://books.google.com/books?id=RyqcAAAAMAAJ&q=%22h%E1%BB%91+ga%22+cho+x%C3%AD+nghi%E1%BB%87p |title=Tìm hiểu quy định về quy hoạch, xây dựng, & cấp giá̂y chứng nhận quyền sở hữu nhà ở: áp dụng tại thành phố Hồ Chí Minh và các tỉnh, thành phố trực thuộc Trung ương |date=2002 |publisher=Thống kê |language=vi}}</ref><ref>{{Cite book |url=https://books.google.com/books?id=7-rZAAAAMAAJ&q=%22h%E1%BB%91+ga%22+cho+x%C3%AD+nghi%E1%BB%87p |title=Tuyển tập các tác phẩm báo chí Việt Nam thời kỳ đổi mới, 1985-2004 |date=2005 |publisher=Hội nhà báo Việt Nam |language=vi}}</ref> The distance between manholes in homes or restaurants is typically 7-10 meters.<ref>{{Cite web |date=2013-10-31 |title=Cách sử dụng hố ga ngăn mùi hiệu quả |url=https://baobinhdinh.vn/viewer.aspx?macm=27&macmp=27&mabb=12506 |access-date=2023-12-20}}</ref><ref>{{Cite web |last=Minh |first=Huy |title=Nắp hố ga |url=https://thanhanco.vn/nap-ho-ga.html |access-date=2023-12-20 |website=thanhanco.vn}}</ref><ref>{{Cite book |last1=Phan |first1=Thanh Khôi |url=https://books.google.com/books?id=rdDsAAAAMAAJ&q=%22h%E1%BB%91+ga%22+%22gia+%C4%91%C3%ACnh%22 |title=Một só̂ vá̂n đè̂ kinh té̂ - xã hội trong tié̂n trình công nghiệp hóa, hiện đại hóa vùng đò̂ng bà̆ng sông Hò̂ng |last2=Lương |first2=Xuân Hié̂n |date=2006 |publisher=Nhà xuá̂t bản Lý luận chính trị |language=vi}}</ref>

== Gallery ==
<gallery class="center">
Open Manhole and Cover Mid-City New Orleans.jpg|A round manhole in New Orleans, and its cover
Bueirocemig.JPG|Manhole cover in [[Belo Horizonte]], [[Brazil]]
Cambridgeshire Manhole.jpg|Manhole cover in [[Sawston]], [[Cambridgeshire]]
Manhole.jpg|Installation of a [[sanitary sewer|sewer]] manhole. Upon completion, typically only the top ring and [[manhole cover|cover]] (not pictured) would be visible.
- Manhole cover in Germany -.jpg|Manhole cover of precast concrete in [[Germany]]
Manhole without manhole cover in Villebon-sur-Yvette 4.jpg|[[Storm drain]] manhole without cover in [[France]]
ManHoleDoorFoundersHallGirard1840.jpg|"Man Hole Door" at [[Girard College]], [[Philadelphia]], constructed in the 1840s
Openchannelflow-domed-metering-manhole.JPG|An open [[packaged metering manhole]] made of fiberglass before installation
Sasa manhole cover.jpg|Manhole cover in [[Kibbutz]] [[Sasa, Israel]]
File:HAIFA DOWN TAWN.jpg|Manhole cover in downtown of [[Haifa]], [[Israel]]
Golden manhole cover Tel Aviv.jpg|Painted gold Manhole cover in [[Tel Aviv]], [[Israel]]
</gallery>

== See also ==
{{Commons category|Manholes}}
* [[Packaged metering manhole]]
* [[Sanitary manhole]]

== References ==
{{Reflist|30em}}
* Isles, Paul (2010). "Dover Engineering Works". ''Dover Life Magazine''

== Further reading ==
* {{cite book |last1=Ascher |first1=Kate |last2=Marech |first2=Wendy |title=The works: anatomy of a city |year=2007 |publisher=Penguin Press |location=New York |isbn=978-0-14-311270-9}}

{{Man-made and man-related Subterranea}}
{{Authority control}}

[[Category:Manholes| ]]
[[Category:Public utilities]]
[[Category:Subterranea (geography)]]
[[Category:Street furniture]]
[[Category:Sewerage]]