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SECTION 8 ♦ Repair Proc ures 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 ( / feet. i FIGURE 1.8.4 a. Cut out the damaged section of pipe. b. Taper one end of a piece of pipe at least as long as may be left on or removed after heat curing, depend- the damaged section. When tapering, carefully ob- ing on their salvage value. serve the position of the nipple on the tapering tool. This taper will be used as a gauge. Cut this 1.8.3 Repairing Extensive Damage nipple to the proper length in the following steps. When the'damaged area in the pipe wall is larger than two c. When pipe is buried, excavate a working area large inches(50 mm)in diameter,follow these instructions: enough to allow for tapering tool rotation. Taper the cut ends of the pipeline and install the two 1. When!damage is local(less than two inches/50 mm sleeve couplings. Cure these joints and then mea- long,Put more than two inches/50 mm around the cir- sure the gap between the sleeve couplings. At this cumfetence of the pipe), check to see if there is enough point, determine the proper length of the pipe nip- slack in the pipe to cut out the damaged section. If ple. This length is the sum of the distance between there is enough slack,cut out the damaged section, re- the two sleeve couplings, the insertion length of taper the cut ends, and bond a sleeve coupling be- the tapered ends, and an additional"wet" make-up tween the tapered ends. Make sure that the joints are length to assure joint lock-up. locked]up and fully cured before pressure testing the repair. To determine the insertion length of the tapered ends, move one of the couplings to the side and If the pipe is buried, excavate a working area large use the end of the repair nipple made in the previ- enough to allow for tapering tool rotation. Taper the ous step to determine the dry fit into each bell. cut ends of the pipeline and install the sleeve coupling (Note: The dry fit must be very tight, i.e.use a 2x4 using the procedures shown in Fig. 1.8.5. 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) i Pipe Size Make-up Dimensions FIGURE 1.8.5 (in.) O (in.) mm}; 2 50 3 2. When�damage is extensive(too large for replacement 3 X3�` 5 by a sleeve coupling), cut out the damaged section, ta- 4 11100 X6 S per the cut ends, and install two sleeve couplings and a pipe nipple as shown in Fig. 1.8.6. This procedure re- quiresufficient slack in the line to make the final This added length is needed due to additional in- joint by lifting the pipe(or moving the pipe to one 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. FIGURE 1.8.6 20 Installation Instructions i