Fusion
For above ground repairs, when the pipe can be moved, the damage can be cut out and replacement pipe can be butt fused or electrofused into the system. However constrained installations, such as buried pipes, may not allow such movement. Fusion repairs of constrained pipes may require techniques and fittings that do not require longitudinal movement, such as spool assemblies with electrofusion couplings.
For local damage for a hole of 2-in. or smaller, an electrofusion patch may be employed as a permanent repair. For larger holes, the mechanical full circle band clamps are recommended (see section on Full Circle Band Clamps), or complete replacement with a spool piece (see sections` on Mechanical Repairs).
Note: The deployment of fusion techniques for the field repair of HDPE pipe for damaged buried water lines is possible but requires additional training and expertise due to challenging (wet, dirty) conditions typically encountered in such applications. Reliable fusion (including electrofusion) connections must be performed under clean, dry conditions. When such conditions cannot be provided, mechanical repairs should be employed. However, since fusion remains the ideal method of connection of HDPE pipe, including repair, where feasible, the importance of proper information and training cannot be over-emphasized. (See section on Fusion Training.)