For raising manhole covers when pavement is resurfaced.
Adjusting rings or extension rings, as they are sometimes called, eliminate
the necessity of raising or replacing existing manhole frame on resurfacing
projects. The cover recess is the same depth and diameter as the existing
manhole frame. Amount of raise coincides with thickness of resurfacing
material, thereby bringing the manhole lid to new position flush with
refinished roadway surfaces. Manhole adjusting rings can be placed
rapidly and are a permanent installation. Use of adjusting rings may reduce
raising costs to as little as 20% of digging up the old manhole frame and
resetting it to new grade.
