As such reforms to strengthen the national organization were being made in the early part of the century, however, some locals broke ranks to form a rival union.

In August 1906, members of the secessionist union realized the futility of further rivalry and agreed to affiliate with the United Association.

The conflict affected other building trades when walkouts by the rival steamfitting organizations, as a result of their jurisdictional dispute, led to work stoppages by other crafts.

New disputes arose over the construction of chemical plants and other manufacturing and service establishments that required extensive piping systems.

Large volumes of newer types of pipefitting installation in the shift from World War I wartime industries to peacetime construction caused considerable difficulties.

Throughout World War II and after, the United Association made considerable gains in membership and prestige.

United Association member George Meany was elected in 1952 to be president of the newly formed AFL-CIO and was to provide a shaping force in the American labor movement until his death in 1980.