Editing Manhole (section)

== 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>