Overview of the use of stainless steel water pipes in different regions

New York's water system has used stainless steel since the 1960s. The U.S. Environmental Protection Agency (EPA) has made strict regulations on the selection of water pipe materials. The choice of pipe materials must meet the requirements of high water quality, low maintenance and long life. The National Standard/National Sanitation Fund International Standard ANSI/NSF61-1997A formulated by the U.S. government in accordance with the Water Purification Act of 1996 clearly stipulates: "For metal pipes used for drinking water, only stainless steel and ductile iron pipes are allowed." Urban tap water supply network , Where the main pipe is reconstructed, stainless steel pipes and ductile iron are used; for the water supply pipes entering high-rise buildings, stainless steel water pipes are the first choice.

The latest 2003 edition of the American International Standards Committee's Plumbing and Residential Standards again includes this aspect and clarifies that the materials required by the standard are 304/304L, 316/316L stainless steel.

This standard was subsequently confirmed by other agencies such as Health Canada, the Netherlands Sanitary Accreditation Board and the World Health Organization. More and more countries now require the pipes and system components of drinking water systems to meet the above standards as the basis for health assurance.

The reason why the United States chooses stainless steel is entirely based on the consideration of economic and health. The corrosion resistance is greatly reduced, the installation and processing costs are greatly reduced, the daily operation and maintenance costs of the pipeline are also greatly reduced, and the service life of the water system can be as long as 100 years, so the total cost over the entire life cycle is the lowest.

At present, in the United States, stainless steel has been successfully applied in more than 100 drinking water treatment plants and transportation systems, and has become the standard material for more than 1,600 urban sewage treatment plants. More than 30 drinking water treatment plants use stainless steel instead of ductile iron pipes. 30-year-old stainless steel pipes at Massachusetts Water Works are still shining like new; New York City adopted 304L stainless steel on a large scale in 1993 for large-diameter risers and other pipes in city water pipelines, with the goal of extending the life of the system 100 years; Detroit, the United States spent 300 million to build a large sports field - Ford Stadium, the water supply system in the water supply system, including the direct drinking water pipes of each point of sale, all use 304 stainless steel.

Japan has been using stainless steel pipes for 40 years. Now stainless steel pipe has been recognized by the Japanese as "the best drinking water container material".

The materials used in the Tokyo water supply pipe network were replaced several times between 1955 and 1980, from galvanized pipes to plastic pipes and steel-plastic composite pipes. Although the water leakage problem was partially solved, the leakage rate reached an unacceptable level in the 1970s. 40% to 45%, and the problem of "hidden water" is gradually reflected, and the problem of non-environmental protection of plastic pipes and steel-plastic composite pipes has become prominent. The Tokyo Water Supply Bureau has carried out a large number of experimental studies on the problem of water leakage for more than 10 years, and finally determined that all water supply pipes with a diameter of less than 50mm use stainless steel pipes, pipe joints, elbows and faucets, and the result has fundamentally solved the problem of water leakage. In 1982, Japan developed a stainless steel corrugated pipe. The pipe user can easily bend it to any angle, greatly reducing the number of joints or even eliminating joints completely, saving installation time and cost.

In 1980, Japan formulated an industrial standard (JIS G 3448—Stainless steel pipes for general piping”, and in 1982, the Japan Water Works Association formulated “JWWA G 115— Stainless steel pipes for tap water” and “JWWA G 116— Stainless steel for tap water.” Steel pipe joints" standard, and later developed a stainless steel corrugated water pipe standard.

In the 1990s, after the 0-157 pathogenic coliform poisoning incident in 1996, people paid more attention to water quality, and stainless steel pipes and water storage equipment that could obtain good water quality were generally welcomed and widely used. In addition, Japan is an earthquake-prone area. In the Great Hanshin Earthquake in 1995, stainless steel water tanks and pipes were not only not damaged by the earthquake due to their high strength and excellent impact resistance, but also assumed the task of supplying drinking water to people in the ruins. As a result, the outstanding seismic resistance of stainless steel water tanks and pipes has attracted attention.

Now in Tokyo, Japan, the penetration rate of stainless steel water supply pipes has reached almost 100%, and all residential areas have installed stainless steel pipes, which greatly improves water quality and enhances earthquake resistance. Also, a large number of dual-purpose aqueduct bridges (both as water conduits and bridges) are also widely constructed of 304 or 316 stainless steel, with nearly 3,000 stainless steel aqueducts constructed since 1983.

The Singapore Water Authority is preparing to replace the water supply pipes under its jurisdiction with stainless steel pipes, with the aim of providing sustainable water resources for the people of Singapore in the 21st century, significantly improving water quality, improving system reliability and significantly reducing operating costs. At the same time, thousands of tons of stainless steel will be used for large-scale replacement and transformation of the existing sewage treatment system. The project will cost S$7 billion over 20 years, and will bring about billions of S$ in economic and social benefits.

The main water supply pipes in some ancient European cities are asbestos cement pipes and cast iron pipes, and the water loss due to leakage is as high as 40%. Since 1980, Germany has used a large number of stainless steel materials in the tap water system to save water resources. The German company Mapress is the largest pipe fitting manufacturer in Europe, with an annual production of 40 million pipe fittings. Sales figures in 2001 show that stainless steel pipe fittings accounted for 51% of its sales volume, carbon steel pipe fittings accounted for 44% of sales, and copper pipe fittings accounted for only 5% of sales.

As one of the most high-profile sports events in the world, the 2006 World Cup football stadium - Munich Allianz Football Stadium in Germany, most of its water supply system uses stainless steel water pipes, because stainless steel has the most stable and reliable performance, clean and hygienic, Water pipes that can fully meet the requirements of German construction standards for transporting drinking water must have at least 5O years of life.

Since 1995, Italian cities have generally adopted a technology that does not require trenching to replace the main water pipelines with stainless steel pipes. Experience has shown that stainless steel pipes are corrosion-resistant, high-strength, able to withstand ground subsidence and earthquakes, and have a lifespan of at least 70 years. Alternative pipes such as plastic pipes are more economical.

After 10 years of testing in Karls Koga, Sweden, the main pipes of ductile iron and PVC buried water supply have all been replaced with 316 stainless steel pipes.

British hospitals (Scotland) used copper water pipes in the past, but the soft water quality in Scotland led to corrosion and failure of copper water pipes, resulting in serious water leakage. The government spent a lot of money to study the cause and solution of the failure, and later all the hot and cold water pipes were replaced with stainless steel water pipes and joints. After more than ten years of use, the cold and hot water pipes were disassembled to investigate the use of the stainless steel pipes and joints. The results showed that the stainless steel pipes and joints were in excellent condition and there was no sign of corrosion.