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ENVIRONMENTAL HEALTH <br />DEPA' RTIM.=sQT <br />Using a Sleeve Coupling <br />• When damage is local (less than two inches (50 mm) <br />long but more than two inches (50 mm) around the cir- <br />cumference of the pipe), check to see 4 there is enough <br />slack in the pipe to cut out the damaged section. If so, <br />cut out the damaged section, re -taper the cut ends, and <br />bond a sleeve coupling between the tapered ends. The <br />joints must be locked up and fully cured before pressure <br />testing the repair. <br />• If the pipe is buried, excavate a working area large <br />enough to allow for tapering tool rotation. Taper the cut <br />ends of the pipeline and install the sleeve coupling. <br />Repairing Extensive Damage <br />When the damaged area in the pipe wall is larger than two <br />inches (50 mm) in diameter, follow these instructions: <br />When damage is extensive (too large for replacement by a <br />sleeve coupling), cut out the damaged section, taper the cut <br />ends, and install two sleeve couplings and a pipe nipple (and <br />other components, if required). This procedure requires suf- <br />ficient slack in the line to make the final joint by lifting the pipe <br />(or moving the pipe to one side) to engage the bell and spigot <br />joint. Therefore, it may be necessary to remove additional <br />backfill from a buried line to allow the pipeline movement of <br />several feet. <br />Taper one end of a piece of pipe at least as long as the dam- <br />aged section. This taper will be used as a gauge. Cut this <br />nipple to the proper length in the following steps. <br />To determine the insertion length of the tapered ends, move <br />one of the couplings to the side and use the end of the repair <br />nipple made in the previous step to determine the dry fit into <br />each bell. (Note: The dry fit must be very tight, i.e. use ad- <br />ditional force to drive the joint together tightly enough that it <br />is difficult to separate.) The total length of the repair nipple <br />is determined by adding these two measurements to the dis- <br />tance between the sleeve couplings and then adding the two <br />make-up dimensions from table below. <br />This added length is needed due to additional insertion that <br />occurs because the adhesive acts as a lubricant. Caution: <br />This additional insertion will be greater it a tight, dry fit is not <br />achieved when measuring. <br />35 <br />