What Does Curing Time Mean?
Curing time, in the context of trenchless rehabilitation, is the time required by the resin-impregnated cured-in-place pipe (CIPP) liner to set inside the host pipe.
Curing time varies depending on the method used to cure the liner – hot water curing takes longer than steam curing. The curing process begins as soon as the components of the resin are mixed. Curing time and temperature are two parameters that are important for proper curing that will result in a liner that has a good finish without wrinkles or folds.
Trenchlesspedia Explains Curing Time
The most favored method of pipe rehabilitation is CIPP, which involves the use of a resin-soaked liner that is inverted and inserted into the affected pipeline after the pipeline is cleaned and inspected. Once placed within the pipe, the liner is expanded using compressed air or steam, filling the pipe. Heat is applied to the liner to accelerate the curing process.
Another method is the fold and form liner, in which the liner is pulled in, and any stress transferred to the liner is relieved. Steam is delivered to the liner from a heat source for a uniform rise in temperature throughout the liner. Once the liner is formed, compressed air or a mix of water and compressed air is used to cool the liner.
When the temperature of the exhaust air or water and air mixture is a constant 110°F for at least 20 minutes, the curing is considered complete.