1. The pipe need not be beveled for weld preparation.
2. Temporary tack welding is no needed for alignment, because in principle the fitting ensures proper alignment.
3. The weld metal can not penetrate into the bore of the pipe.
4. They can be used in place of threaded fittings, so the risk of leakage is much smaller.
5. Radiography is not practical on the fillet weld; therefore correct fitting and welding is crucial. The fillet weld may be inspected by surface examination, magnetic particle (MP), or liquid penetrant (PT) examination methods.
6. Construction costs are lower than with butt-welded joints due to the lack of exacting fit-up requirements and elimination of special machining for butt weld end preparation.