we had a plumber , replumbing a bus terminal one time, using the swedge lock fittings, he didn`t get all the ferrules in the same, and the lines blew apart sometime in the middle of the night, they were hyd. service lines. U would not believe the mess he had to clean up! barrels and barrels of the stuff. I would have used double flairs "or inverted flairs) , and I did. the factory used them !
