Originally developed to isolate and dampen vibration in hydraulic hoses within steel housings, modular mechanical seals are now used to permanently seal and protect pipes passing through concrete walls, floors, ceilings, and other barriers. They can be used to seal ductile iron, concrete, metal, and plastic pipes within the holes they traverse, accommodating piping up to 144 in. in diameter and providing hydrostatic sealing up to 20 psig, or 40 ft of static head.
These devices are installed around the external circumference of the pipe, sealing it more quickly and effectively than lead-oakum joints or hand-fitted flashings, mastics, or casing boots (Figure 1). The seals expand when tightened to fill the annular space between the pipe and the cored or formed penetration, which is defined as half the difference between the inside diameter of the penetration and the outside diameter of the pipe.