Chimney Seals

The Internal/External Adaptor Seal (I/E.A. Seal) is a sanitary manhole seal which prevents infiltration into the sewer system. The I/E.A. Seal stops inflow between the manhole frame and the top adjusting ring, it also seals the manhole chimney from the frame to the corbel.
 
The design of the I/E.A. Seal produces a rubber gasket seal, which seals the manhole frame and allows it to move with the road surface due to frost movement and thermal expansion. It also produces a stress barrier between the frame and the manhole chimney from direct load bearing of the traffic.
 
This will help preserve the integrity of the manhole chimney.

For addition info check out the following link: http://www.adaptorinc.com/install.htm