First of all, starting from the material of the faucet , copper is the best material for the current faucet manufacturing. At present, most of the products on the market are copper faucets, both in Europe and America. The main materials of copper faucets are copper and zinc, commonly known as brass, which require a small amount of lead in the process of producing a faucet to improve the cutting performance of brass. If lead is not added at all in the faucet production, problems such as difficulty in cutting and poor forging performance may occur, and even if it is made into a finished product, cracking may occur due to poor resistance to stress corrosion.
Copper faucets are inseparable from lead. Why are the mainstream faucets in developed countries in Europe and America all made of brass, and copper is not replaced by other materials? The main reason is the bacteriostasis of copper. According to historical records, Egypt began to use copper for wound disinfection, treatment of eye infections and burns, and disinfection of drinking water before 2500 BC. The scientific evidence of many world authorities such as the US EPA (Environmental Protection Agency), antibacterial copper in two Killing more than 99.9% of the bacteria in an hour is the most effective contact surface material in the world, and no other material (such as silver ion coating or stainless steel) can match it.
Vertical coordinate: Bacterial volume abscissa: time
Copper can quickly kill super bacteria such as MRSA, and bacteria can not produce antibodies. The inner wall of copper faucets will not breed bacteria, which is not the advantage of other materials (such as stainless steel, plastic). With the low-lead copper (lead content less than 0.25%) mass production, the improvement of antibacterial properties, there is reason to believe that in the future is still the best material for faucet manufacturing.
Causes and hazards of lead in brass faucets
At present, the main material for domestic production of faucets is brass HPb59, which requires less than 1.9% lead. Due to the lack of standards, some manufacturers use brass lead content of 3% to 6% in order to reduce costs and improve the cutting performance of brass. . The temperature of the faucet casting is generally 1053 ° C, and the melting point of lead is 327.5 ° C, so that lead is segregated on the inner and outer surfaces during molding, and the lead content on the surface is 3 to 5 times higher than the internal. The lead removal process can be used to remove lead from the surface. However, the water flowing in the faucet will destroy the surface of the lead-washing, forming "corrosion", and the internal lead ions are exposed again, so that the lead content precipitated increases. To this end, the United States has introduced low-lead copper to solve the problem of lead precipitation from materials.
The heavy metal in the faucet is the most harmful to lead. According to expert research, the body resistance of children is poor, the absorption rate of lead is more than 5 times that of adults; and the sensitivity to lead is extremely strong, and the lead content in 100 ml of blood reaches 50. -60 micrograms is enough to poison. And this number is only about 80-100 micrograms for adults. The total IQ, operational IQ, and language IQ of children with high blood lead are significantly lower than those of children with low blood lead.
Domestic and international lead limit standards and testing
The lead content of the faucet is expressed in two ways, one is the mass percentage of lead in the raw material, and the other is the amount of micrograms of lead per liter of water after the dip test or expressed by the Q value. Need to remind consumers that this is two different concepts, the lead value of raw materials meets the requirements does not necessarily mean that the lead value of the leaching meets the requirements.
The NSF61 is the most representative in the United States, and the technical requirements and test methods of the domestic faucet JC/T1043-2007 "water nozzle lead precipitation limit" standard are the same as those of NSF61. JC/T1043 specifies at least 3 sets of samples of the same specification during the test period. From Monday to the same day, change the water every 2 hours, take the 2nd, 3rd, 4th, 9th, 10th, 11th, 16th, 17th, 18th and 9th days of immersion for 16 hours of water for testing. The JC/T1043 standard requires lead statistics. The value is less than 11ug (the mandatory new version of GB18145 issuance in 2014, the Q value is 5ug), which means that the Q value of lead leaching is related to the volume of the product and the stability of the product. The value of the device test. At present, the most authoritative testing institutions in China include the National Plumbing Hardware Testing Center and the China Quality Certification Center Guangzhou CQC Laboratory.
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