Pipe fusing is a method of seamlessly joining together two high-density polyethylene (HDPE) pipes that are commonly used as the conduit in HDD. The HDPE pipe is heated and the molecules are transformed into a crystalline state enabling a seamless fuse. The end result is a joint that is as strong, or stronger, than the pipe itself.
Strong fusions are essential as HDPE pipe is subject to soil loads without side support from the surrounding hole.
This load requirement and the failure and liability concerns that it can produce is a major difference between HDD pipe and pipe installed in a traditional trench.