Here are some facts that show advantages and disadvantages of each type:
Heat fusion, electrofusion, and mechanical fitting installations have been proven safe in the industry, as long as proper procedures are performed.
For each mechanical fitting connection (coupling), two connections must be made. For butt fusion, only one connection is made.
Compared with mechanical fitting joints, butt fusion has by far the fewest failures, as documented by the U.S. Department of Transportation.
Minor scratches on PE pipe/tubing can be detrimental and are prohibited by the manufacturer when installing compression and stab-type mechanical fittings.
Fusion joints, when performed correctly, become stronger than the pipe itself.
For butt fusion, no materials other than polyethylene are in the connection; thus, there’s no possibility of corrosion.
Qualified fusion personnel must ensure that required fusion pressure is calculated correctly with hydraulic fusion units.
Butt heat fusion is the most widely used method for joining individual lengths of PE pipe and pipe to PE fitting. (This method produces a permanent, economical, and flow-efficient connection.)
Mechanical or electrofusion couplings are frequently used for convenient replacement of damaged PE pipe segments.
Butt fusion joints are used in manufacturing some mechanical fittings.
Tip: It’s important to understand that any approved method of PE pipe joining will be successful if every facet of the procedure/process is followed correctly. I cannot stress enough the vital importance of pipe/fitting preparation (cleanliness) and ensuring that all completed joints are inspected thoroughly!