What Does Plug For Manhole Mean?
Plugs for manholes are made of rugged rubber and normally used to perform spot leaks or test the air quality in an adjoining sewer. They are typically inflated and filled with an inert gas or water after being put in place. However, they may also be mechanical or consist of epoxy resin for more permanent installations. Operations in which plugs for manholes are used include air tightness tests, smoke tests, water tightness tests, and to deviate or divert effluents.