Ductile iron is the leading material for water pipes in Japan, with ductile iron pipes^*1 accounting for approximately 60% of Japan’s total water piping.^*2 Ductile iron was first developed in the US in 1948, and garnered worldwide attention as the greatest invention of the century in materials. Ductile iron was strong and flexible, and combined the corrosion resistance of iron with a toughness on par with steel. At the time, though, use of ductile iron in actual products was thought to be incredibly difficult. In 1954, Kubota became the first company in the world to commercialize ductile iron in its large-diameter ductile iron pipes. A few years later in 1957, Kubota succeeded in the mass production of these pipes. In earthquake-prone Japan, Kubota utilized the outstanding durability and corrosion resistance of its ductile iron pipes for further development, ultimately leading to its earthquake-resistant pipes.^*3

Like Japan, parts of the US are also prone to earthquakes, and these areas had long been looking at ways to earthquake-proof their water pipelines. One such area was California on the West Coast, under which lay the San Andreas Fault, which has been the cause of a number of large earthquakes in the past. Unfortunately, key water supply facilities and pipelines—essential to life and society—lie atop this dangerous fault line. If a large earthquake were to occur, there was every possibility that the infrastructure would collapse in an instant. As such, for the Los Angeles Department of Water and Power (LADWP), building an earthquake-resistant pipe network was a matter of urgency.

It was around this time that the LADWP took notice of Kubota’s earthquake-resistant ductile iron pipes, which were completely damage-free following the massive the Great Hanshin-Awaji Earthquake and the Great East Japan Earthquake. In meetings with individuals from the LADWP, Kubota promoted its pipes’ features—pipe joints that expand and contract and follow the movement of the ground in the event of an earthquake, creating a structure that prevents the pipes from coming apart. Impressed with the pipes’ performance and their ability to withstand huge earthquakes, in 2013, the LADWP became the first organization in the US to adopt Kubota’s GENEX pipes. GENEX were Kubota’s most advanced earthquake-resistant pipes to date, and were designed to last for 100 years. Since then, these earthquake-resistant pipes have been adopted on a trial basis in a range of locations from California to Oregon.

Since developing vertical-blow rotary-type casting equipment in 1904 and becoming the first company in Japan to succeed in the mass production of water pipes, Kubota has continued to evolve its pipes with earthquake-resistant functionality, longer lifespan, and other features. Looking ahead, Kubota’s earthquake-resistant pipes will continue to support global water infrastructure from under the ground.