Tokyo Gas Chemicals (President: Toshiyasu Ishii) having head office in Minato-ku Tokyo marked its construction record of 455 cases in 2015 with the pressure welding method “Eco Speed” using polymeric natural gas. A total of 2,133 cases have been attained since 2011 when the construction method was approved. The method employs natural gas instead of acetylene for the pressure welding of reinforcing steel for construction. Comparing with acetylene which requires skilled engineers, even a beginner can deal with the method easily.

Reinforcing steel easily gets oxidized under the environment of high temperature. Oxidization exerts great influences to the quality of fittings. Therefore an anti-oxidizing process turns out to be important. In the pressure welding in use of acetylene has required difficult techniques like flame adjustments or the stationary fixing of burner. The company tried to apply PS rings on reinforcing steel to prevent oxidization, so that pressure welding can be done with just heating around the joint area.

The simple constructing technique reducing environmental burdens and technical skills drew so much attention that the number of construction cases increased. When the “ECOWEL Association” was formed in 2005, only 20 companies adopted the method, but it increased up to 62 cases as of June 2016.

Masaaki Fujihira manager of cylinder gas said, “Acetylene and natural gas have both merits and demerits. Regarding the demerits of natural gas in awareness or constructing system, we see a gradual improvement with increased inquiries and a steady growth in the number of qualified constructers.” With regard to the “Hydrogen/Ethylene-mixed Pressure Welding” method approved at the end of September 2015, he commented “We expect a revised boom of pressure welding with the new construction method although there has been an increase of pressure welding year after year due to the diffusion of methods other than gas welding.” The company places a target for the future at 5,000 cases of construction and a market share of 20%.