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SECTION 8 ♦ Repair Procedures FIGURE 1.8.4 may be left on or removed after heat curing, depend- ing on their salvage value. 1.8.3 Repairing Extensive Damage When the damaged area in the pipe wall is larger than two inches (50 mm) in diameter, follow these instructions: When damage is local (less than two inches/50 mm long, but more than two inches/50 min around the cir- cumference of the pipe), check to see if there is enough slack in the pipe to cut out the damaged section. If there is enough slack, cut out the damaged section, re - taper the cut ends, and bond a sleeve coupling be- tween the tapered ends. Make sure that the joints are locked up and fully cured before pressure testing the repair. If the pipe is buried, excavate a working area large enough to allow for tapering tool rotation. Taper the cut ends of the pipeline and install the sleeve coupling using the procedures shown in Fig. 1.8.5. FIGURE 1.8.5 2. When damage is extensive (too large for replacement by a sleeve coupling), cut out the damaged section, ta- per the cut ends, and install two sleeve couplings and a pipe nipple as shown in Fig. 1.8.6. This procedure re- quires sufficient slack in the line to make the final joint by lifting the pipe (or moving the pipe to one 20 FIGURE 1.8.6 side) to engage the bell and spigot joint. Therefore, it may be necessary to remove additional backfill from a buried line to allow for pipeline movement of several is feet. a. Cut out the damaged section of pipe. b. Taper one end of a piece of pipe at least as long as the damaged section. When tapering, carefully ob- serve the position of the nipple on the tapering tool. This taper will be used as a gauge. Cut this nipple to the proper length in the following steps. When pipe is buried, excavate a working area large enough to allow for tapering tool rotation. Taper the cut ends of the pipeline and install the two sleeve couplings. Cure these joints and then mea- sure the gap between the sleeve couplings. At this point, determine the proper Iength of the pipe nip- ple. This length is the sum of the distance between the two sleeve couplings, the insertion length of the tapered ends, and an additional "wet" make-up length to assure joint lock-up. To determine the insertion length of the tapered ends, move one of the couplings to the side and use the end of the repair nipple made in the previ- ous step to determine the dry fit into each bell. (Note: The dry fit must be very tight, i.e. use a 2x4 to drive the joint together tightly enough that it is difficult to separate.) The total length of the repair nipple is determined by adding these two measure- ments to the distance between the sleeve couplings and then adding the two make-up dimensions from Table 1.8.1. TABLE 1.8.1 Make-up Dimensions (Wet) Pipe Size Make-up Dimensions (in.) (mm) (in.) (mm) 2 50 X 3 3 75 / 5 4 100 5 This added length is needed due to additional in- sertion that occurs because the adhesive acts as a lubricant. (Caution: This additional insertion will be greater if a tight, dry fit is not achieved when measuring. It will also be different for each size of pipe.) After the final nipple length is determined, cut the other end of the nipple and taper it, making sure that the nipple is on the tapering tool in exactly the same position as the first taper, which was used to measure the insertion length, is Installation Instructions