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1. a shaft with a removable cover that leads down to a sewer or drain
2. a hole, usually with a detachable cover, through which a man can enter a boiler, tank, etc.



a structure in a sewer network used for inspecting, cleaning, and flushing the sewers.

The manhole usually consists of a work area and, above it, an entrance area, a hatchway, and a lid. There are inspection manholes, drop shafts, and flushing shafts. Among the inspection manholes there are line shafts, built at straight sections of the sewer network; corner shafts, where the line changes direction; juncture shafts, where several lines come together; and control shafts, where the networks draining individual buildings or city blocks join the street network. Drop shafts are built where there is a substantial difference between the levels of the delivery pipes and drain pipes. Flushing shafts are used in flushing out the sediments that form in pipes carrying effluents with a slow rate of flow.

In cross section, manholes are either round or rectangular. They are built predominantly from prefabricated reinforced-concrete rings and panels. Sometimes they are brick.



An opening to provide access to a tank or boiler, to underground passages, or in a deck or bulkhead of a ship; usually covered with a cast iron or steel plate. Also known as access hole; manhead.


A covered opening in a street which provides access for cleaning and repairing of a sewer beneath, or for repairing a conduit for electric underground piping or electric cables.
References in periodicals archive ?
Existing maintenance holes will be removed and replaced to restore the integrity of the structure and new maintenance holes will be added to allow future operation and maintenance of this sewer.

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