Manhole covers are made of cast iron. These covers need to be heavy so that when vehicles drive over them, they do not become dislodged. Manhole covers normally weigh 100+ pounds each. Some have open pick holes which allow water to enter the manhole. Others have concealed pick holes which do not go all the way through the cover or lift handles such as drop handles or ring handles. Manhole covers can be bolted to the frame for security reasons. Manhole covers can also have a gasket on the bottom of the cover and bolted to the frame which is normally considered watertight.
Sincerely Plantautomation Technology
Regards,
Client Success Team (CRM),
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