Show I IRRIGATION TION PIPING PIPING SUBJECT TO TEST rEST The need for standardizing the thc metho methods meth moth o s o of manufacture and the development develop elop ment of standard tests and testing equipment to determine the strengths of ot concrete pipes has haH resulted has resulted in the establishment of or a n. field laboratory b by th the bureau J of or public roa roads lI United j I States department of ot agriculture where equipment Is being experimented with and arid t tests have havo been ma mado e to determine deter deter- I mine tho the tensile strength resistance to internal pressure tho the and per of oC forty orl kinds o of concrete pipe no now used In Irrigation Irrl These investigations In lions have been prompted In part by 11 tho the hl high h cost of or Iron and find steel which has bias greatly enlarged ed tho the demand for or concrete con con- concrete crete crele pipe to meet rigid conditions In Irrl irrigation atlon systems notably pressure pres pres- sure pipe is needed to calr carry Mater Under Under un Un- der high heads California alone has now moro more than lliO concrete pipe manufacturers manufacturers manu manu- and concrete pipe is bein being laid at the tho rate of or many hundred mlles miles a year I |