Tomoaki Takeuchi, Akira Takahashi, Hidenobu Nakai, Kenichi Ishii, Yoshiyuki Makino, Kozo Imai and Tetsuo Inoue
A flexible pipe for gas transmission with composite structure has been developed, which can be installed without joints for long distances along meandering open-cut routes or in underground conduits. The structure of this pipe is such that multiple stainless steel tapes are gap wrapped in spiral on a polyethylene pipe, whereby the steel tape thickness is optimized to make the pipe applicable to a wide pressure range from medium-to high-pressures, while maintaining flexibility by minimizing the pipe wall thickness. Moreover, earthquake resistance is one of its advantageous features. In this report, the design of the steel tape-armored polyethylene pipe in conformity to the Technical Standard for Gas Facilities of Japan is described, together with the results of various characteristic evaluation tests on the prototype pipes.