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hose is used to evacuate air, let the liner disappear into the standpipe and stop the water flow and <br />the installation to allow all the air to evacuate. Before continuing with the installation bend the <br />heater hose over onto itself and tape it securely to prevent water from entering into the liner. <br /> <br />Once the liner enters the standpipe, use the hold back rope to restrain the inversion of the liner. <br />Do not pull on the blue discharge hose since it will more easily tear since it does not have the <br />strength of the braided rope. In addition, as the blue circulation hose is being fed into the <br />standpipe, constantly monitor this hose to ensure it also goes into the liner without any twists and <br />that the splices are made in the correct direction. <br /> <br />Restrained Sample Ring and Bulk Heading--When the liner is within 10-20 feet (3-6 m) of the <br />end of the pipe, place your sample restraining ring and bulk-head in the downstream manhole. <br />Refer to the "Sampling" section for guidance on proper sample size. After the sample piece is in <br />place and the end properly bulk headed (as necessary) the liner is fully inverted through the <br />restraining ring and up against the bulkhead. <br /> <br />Final Filling -- After the liner has been fully installed and bulk heading (if necessary) is complete, <br />fill the column according to the recommended curing head. Ideally, the liner should be filled to the <br />recommended level for maximum hot curing. Allow the liner to expand and fit tightly against the <br />host pipe. However, one must also consider the conditions surrounding the pipe being <br />rehabilitated when determining the final proper initial and curing water head pressures. The <br />standpipe head pressure should be a minimum of 3 psi (6-7 feet of water) greater than that of the <br />known ground water around the pipe or full service lateral pressures. <br /> <br />Prior to proceeding with the curing and cool down procedures put the plate molded sample into <br />the standpipe if this method of sampling is being utilized. <br /> <br />CURING AND COOL DOWN <br /> <br />As the liner is initially heated in the first stage of the curing process, the lining tube will have <br />stretched and the water head may be lowered to where it is between the maximum hot and <br />recommended water column heights. <br /> <br />Variable or Staged Cure Strategy -- The temperature and times for curing tubes vary as a <br />function of tube thickness. The purpose is to optimize the water temperature so the resin is cured <br />completely without producing an exotherm so hot to produce damage to the tube. If the resin is <br />allowed to exotherm above 270F (132C) the styrene in the resin will vaporize, producing a liner <br />having a porous, foam-like consistency. This phenomenon is sometimes referred to as "styrene <br />boil." When a liner experiences styrene boil, the properties of the final product may be reduced <br />from that of an optimally cured CIPP. For optimum physical properties and corrosion resistance, it <br />is recommended that the fabric tube be cured under variable conditions based on the thickness of <br />the liner being installed. <br />SAMPLING <br />General -- Considering the various aspects of tube wet out and installation, final CIPP sampling is <br />probably one of the most important procedures of the entire process. Although sampling may <br />seem like a troublesome afterthought to the whole process, it is most important because this is the <br />item by which the installed liner is deemed to be accepted or rejected. Every client specification <br />calls for minimum thickness and physical property requirements for the installed product. The <br />sample taken from the CIPP represents the installed product. If the sample is poorly handled or <br />damaged and the properties measured are substandard, the liner will be rejected on the basis of a <br /> <br />