Abstract: A flexible gasket connecting a plastic or fiberglass pipe in fluid communication with a plastic or fiberglass septic tank. The gasket is an integrally molded elastomer having an annular base with a flange and keeper portions extending radially outward from the base forming a continuous groove sealing around the periphery of an opening in the tank. The keeper portion is tapered axially to enable the gasket to be pushed into the tank opening and snap-fitted into position. A web portion extends inwardly from the middle of the base portion and terminates in a toroidal portion to provide a primary sealing function of the gasket, and the toroidal portion provides a secondary sealing. The added pressure produced by the toroidal portion significantly strengthens the total seal while retaining residual resilience to allow relative movement of the tank and pipe.

Abstract: Prefabricated concrete pipe encasements are disclosed for stabilizing underground conduit systems from movement caused by flotation, back filling or settling. In one embodiment, a sewer chimney includes a plastic riser connected between a tee-fitting in a sewer main and a cap block at a branch service line. At least one pipe encasement and a prefabricated concrete base encircles the riser for maintaining alignment with the tee-fitting. In other embodiments the pipe encasement encircles a generally horizontal pipe line.