There is nothing that will not change, given enough time. Sometimes changes come at a snail’s pace, like a tree growing, and sometimes with lightning speed like, uh, well, like lightning. The common denominator is, of course, change. No matter how tenaciously we cling to our old standby “that's the way it's always been done,” the facts of the matter dictate differently.
Evolution in the trade
In 1905, the industrial revolution was shifting into high gear By 1929 the use of cast iron pipe for drainage, waste, vent, roof and other drainage needs rose in importance By the time of World War II threaded brass pipe for potable water had become the standard in commercial, residential and industrial applications We can all (well maybe not all, but some of us) remember installing 1.6-gpf water closets that were designed for a 3.0-gpf