RE:RE:RE:This is what Whitmer is up againstThanks RF. BTW they dont build anything out of spec. Good catch on the 2.4 times working pressure which determines wall thickness. And there is a further safety applied usually 60 percent of working pressure. Road and river crossings have extra thick pipe. I forgot to mention on bends and all surface piping they stress relieve by heating the material. The compaction and back filling are specified so there is no displacement or piercing by rocks. Didn't mean to be so technical but all that freezing my but off in the field taught me a couple of things