Protected versus unprotected manholes and wetwells

[tigerbob]

Does anyone know of any reseach on the effects of coal-tar epoxy from acid attach on sewer manholes and wetwells? We've had an engineer ask us for reccommendations on standard unprotected manholes vs. Coal-tar vs. mechanical liners. I know that the mechanical liners are the best protection and highest cost, but my main concern is unprotected vs. the coal tar.

tigerbob

 

[dicksewerrat]

Coal tar or Koppers( trademark) is a good coating for RCP if it is applied at the factory. I haven't found a good coating that is applied to existing structures. although some people swear by them. Go to the Trenchless online site for a list of the coating companies.

 

[upwey]

We are designers and makers of sewer valves, covers and frames. We have found that most 2 part epoxy resins are cost effective for valve bodies but rely on bitumen product for the underside of covers. Ductile iron with a triple coat has had the test of time with acceptable results - however, grey iron is more porous and will have faster breakdown following paint coat loss.