1st the water supply pipe into a standardized track
Before 1955, the tap water supply pipeline in Tokyo, Japan, was commonly used for galvanized tubing. In the past 1955-1980 years, plastic pipes and steel-plastic composite pipes were used extensively. Although the water quality problems and leakage problems of galvanized pipe are partly solved, however, the leakage of water supply network in Tokyo is still very serious, leakage rate in the 70 's has reached an unacceptable 40%~45%, and "hidden water" problem is gradually reflected, plastic pipes and steel-plastic composite pipe can not meet the basic requirements of environmental protection.
Tokyo Water Supply Bureau on the leakage problem for more than 10 years a large number of experimental research, according to the analysis, 60.2% of the leakage is due to insufficient strength of the water pipe is caused by the role of external forces, 24.5% of the leakage is due to the unreasonable design of pipe joints, 8% Leakage is due to excessive plastic expansion rate caused by unreasonable pipeline design. To this end, the Japan Watercourse Association has recommended improvements in plumbing materials and connection modes. From May 1980 onwards, from the water supply to the main line to the meter, where the diameter of 50mm below the pipe all the use of stainless steel pipes, fittings, elbows and taps, the results fundamentally solve the problem of leakage. 1982 Japan has developed stainless steel bellows, pipe users can easily bend to any angle, greatly reducing the number of joints can even completely eliminate the connector, saving the installation time and cost.
1980 Japan developed Industrial standards (JIS G 3448--general pipe with stainless steel), 1982 Japan Watercourse Association to develop "JWWA g 115--tap water" and "Jwwa g 116--tap water with stainless steel pipe joints" standards, and then developed a Standard for corrugated steel pipe for rust. In 1999, the Tokyo Water Supply bureau used the 316 stainless steel bellows as the standard material, indicating that stainless steel was used as a tap water pipeline and the water supply pipeline in the building had entered a standardized orbit. According to the Tokyo Water Department statistics, with the rate of stainless steel from 1982 to 11% rose to 2000 more than 90%, the number of leaks accordingly from the 70 to the end of the year from 50,000 to the 2000 2~3 (by stray current caused by leakage of joints), stainless steel pipe used to greatly reduce the water leakage rate.
In the 80 's, especially in 1996, after 0-157 cases of mass poisoning of pathogenic coliform, people pay more attention to water quality, and the stainless steel pipes and water storage equipment which can obtain good water quality are universally welcomed and widely used. In addition, Japan is an earthquake-prone area, in the 1995 Hanshin earthquake, stainless steel tanks and pipelines due to high strength and excellent impact resistance not only not damaged by the earthquake, but also to the ruins of the people to supply drinking water, the task, thus, stainless steel tanks and piping outstanding seismic capacity of the people concerned.
Now in Tokyo, Japan, stainless steel water supply pipe penetration rate of almost 100%, all residential areas have installed a stainless steel pipe, greatly improve the water quality, enhance the seismic capacity. Moreover, a large number of dual-use water bridges (both for water pipelines and used as bridge) are also widely used in 304 or 316 stainless steel construction, since 1983 has been the construction of nearly 3000 stainless steel water transmission bridge.
Japan's use of stainless steel tubing has been 40 years of history. Now the stainless steel pipe has been recognized as the "Best Drinking water container material" by the Japanese.