Application of stainless steel water pipes in drinking water in developed countries

Application of stainless steel water pipes in drinking water in developed countries

1 Japanese tap water supply pipe enters standardized track

Before 1955, the tap water supply pipe in Tokyo, Japan, was commonly used for galvanized pipes. Between 1955 and 1980, a large number of plastic pipes and steel-plastic composite pipes were used. Although the water quality problems and water leakage problems of galvanized pipes were partially solved, the water leakage in the Tokyo water supply network was still very serious. The leakage rate reached an unacceptable 40% to 45% in the 1970s, and the “hidden water” The problem is gradually reflected, plastic pipes and steel-plastic composite pipes can not meet the basic requirements of environmental protection.

The Tokyo Water Supply Bureau conducted a large number of tests on the water leakage problem for more than 10 years. According to the analysis, 60.2% of the water leakage is caused by the insufficient strength of the water pipe material, and 24.5% of the water leakage is caused by the unreasonable design of the pipe joint. The % water leakage is caused by the unreasonable design of the pipeline circuit due to the excessive expansion rate of the plastics. To this end, the Japan Waterway Association recommends improvements in water pipe materials and connections. Since May 1980, from the water-conveying auxiliary trunk to the water meter, all the water supply pipes with a diameter of 50mm or less have adopted stainless steel pipes, pipe joints, elbows and faucets, which have fundamentally solved the problem of water leakage. In 1982, Japan developed stainless steel bellows, which can be easily bent into any angle, greatly reducing the number of joints and even eliminating the joints, saving installation time and cost.

In 1980, Japan established the industry standard (JIS G 3448 - Stainless Steel Pipe for General Pipes). In 1982, the Japan Waterway Association established "JWWA G 115 - Stainless Steel Pipe for Tap Water" and "JWWA G 116 - Stainless Steel Pipe Joint for Tap Water" Standards, and later developed the standard for stainless steel corrugated water pipes. In 1999, the Tokyo Water Supply Bureau used 316 stainless steel corrugated pipes as standard materials, indicating that stainless steel was used as a water supply pipe and a water supply pipe in the building to enter a standardized track. According to the statistics of the Tokyo Water Department With the rate of stainless steel rising from 11% in 1982 to over 90% in 2000, the amount of water leakage has dropped from more than 50,000 per year in the late 1970s to 2 to 3 in 2000 (caused by stray currents). Leakage at the joint), the use of stainless steel water pipes greatly reduces the water leakage rate.

In the 1980s, especially after the collective poisoning of pathogenic coliforms from 0 to 147 in 1996, people paid more attention to water quality, and stainless steel pipes and water storage equipment that can obtain good water quality were widely welcomed and widely used. In addition, Japan is a region with frequent earthquakes. In the Great Hanshin Earthquake in 1995, stainless steel water tanks and pipes were not damaged by earthquakes due to high strength and excellent impact resistance, and they also assumed the task of supplying drinking water to people in the ruins. As a result, the outstanding seismic capacity of stainless steel water tanks and pipes has attracted attention.

Nowadays, in Tokyo, Japan, the penetration rate of stainless steel water supply pipes has almost reached 100%. All residential areas have been installed with stainless steel pipes, which greatly improved water quality and enhanced seismic capacity. Moreover, a large number of dual-purpose water transmission bridges (both as water pipelines and road bridges) are also widely constructed using 304 or 316 stainless steel. Since 1983, nearly 3,000 stainless steel water transmission bridges have been constructed.

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

2 US government promotes the development of stainless steel water pipes

The use of American stainless steel tubing began in the 1960s and prevailed in the 1990s. The US Environmental Protection Agency (EPA) makes rigid regulations on the selection of water pipes. The choice of pipes must meet the requirements of high water quality, low maintenance and long life. According to the National Standard/National Health Fund International Standard ANSI/NSF61-1997a, which was established by the US Government in accordance with the 1996 Water Purification Law, “the metal pipes used for drinking water are only allowed to use stainless steel and ductile iron pipes.” Urban tap water supply pipe network Stainless steel pipes and ductile irons are used for the transformation of the main pipes; stainless steel pipes are preferred for the water supply pipes entering the high buildings. The latest 2003 edition of the American International Standards Board's water and residential standards once again includes this aspect, indicating that the use of stainless steel water pipes has officially been officially approved by the United States. Other countries such as Health Canada, the Dutch Health Appraisal Committee and the World Health Organization have also confirmed this standard. Nowadays, more and more countries require that the pipes and system components of drinking water systems must meet the above criteria as the basis for health assurance. The first batch of materials that meet the requirements of this standard are

304/304L, 316/316L stainless steel.

In the United States, stainless steel has been successfully applied in more than 100 drinking water treatment plants and delivery systems. New York's water supply system has been made of stainless steel since the 1960s. New York City's original drinking water distribution system is old and unable to meet demand. Based on the 15-year evaluation of alternative materials, the authorities adopted large-scale column pipes and other pipes in urban water pipelines in 1993. 304L stainless steel, the goal is to make the system last for up to 100 years. The water supply renovation in the Washington area also uses stainless steel water pipes. The main water pipeline for the water supply system in the Ford Stadium in Detroit, the cost-added 300 million new stadium, includes direct drinking water pipes at all points of sale, all of which are made of 304 stainless steel. In addition, stainless steel pipes have become the standard material for more than 1,600 urban sewage treatment plants built in the United States in the past 30 years.

The reason why the United States chooses stainless steel is based on economic and health considerations. Stainless steel materials comply with the Environmental Protection Agency (EPA) guidelines and are often used in applications where water quality is high and difficult to replace, low maintenance is required, and service life is long. Although the cost of the first material is about 20% to 50% higher than that of the galvanized pipe, due to the excellent corrosion resistance of the stainless steel, 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 is greatly reduced. It can be as long as 100 years, so the total cost over the life of the life is the lowest.

More than 30 drinking water treatment plants in the United States have used stainless steel instead of ductile iron pipes, mainly because of cost savings. The Massachusetts water plant has a cost savings of about $50,000 compared to the use of ductile iron due to the use of stainless steel tubing, and the use of stainless steel tubing for 30 years is still as bright as new.

3 European stainless steel water pipes are gradually popularized

The main water supply pipes in some ancient European cities are asbestos cement pipes and cast iron pipes, which cause water loss of up to 40% due to leakage. Since 1980, Germany has used a large amount of stainless steel materials in the water system to save water resources. Germany Mapress is the largest pipe fitting manufacturer in Europe, with an annual production capacity of 40 million pipe fittings. Sales figures for 2001 show that stainless steel pipe fittings account for 51% of its pipe sales, carbon steel pipe parts for sales of 44%, and copper pipe fittings for only 5% of sales. As one of the most watched sports events in the world, the 2006 FIFA World Cup in Munich, the Allianz football stadium in Munich, Germany, the majority 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 German construction standards for drinking water must have a minimum life expectancy of 50 years.

Since 1995, cities in Italy have generally adopted a technique that does not require trenching to replace the main pipeline of water delivery with stainless steel pipelines. Experience has shown that stainless steel pipelines are corrosion-resistant, high-strength, resistant to ground subsidence and earthquakes, and have a life expectancy of at least 70 years. Substituting pipes such as plastic pipes are more economical.

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

British hospitals (Scotland) used copper pipes in the past, but the soft water quality in Scotland caused corrosion and failure of copper pipes, causing serious water leaks. The government spent huge sums of money to study the cause and solution of the failure. Later, the hot and cold water pipes were all replaced with stainless steel pipes and joints. After more than ten years of use, the hot and cold water pipes were dismantled to investigate the use of stainless steel pipes and joints. The results showed that the stainless steel pipes and joints were in excellent condition with no signs of corrosion.