Impregnation is the process of filling or saturating a porous or absorbent material with a liquid or viscous product. Cured-in-place pipe (CIPP) is a trenchless rehabilitation technique that utilizes a liner which has been impregnated with a viscous resin-like substance to line sewer pipes for the purpose of rehabilitating it. Trenchless methods can be carried out from manholes and do not require excavation of roads or sidewalks to access the pipes.
Trenchlesspedia Explains Impregnation
Impregnation of resin in CIPP liners should be carried out as per American Society for Testing and Materials (ASTM) F-1216, Section 7.2, which requires a vacuum pump and calibration roller. The liner is impregnated with resin under controlled conditions to ensure even and complete wet out. The amount of resin used should be sufficient so that all voids are soaked with even thickness. 5 to 10 percent of resin should be added in excess so that change in volume of resin due to polymerization and filling of cracks and voids in the host pipe are also accounted for without losing resin from the liner itself. This ensures the bonding between host pipe and liner is strong.