f some chemicals (acids) in laboratory make the metal corrode very fast. In water supply pipelines corrosion is not observed very soon. In fact, corrosion does not occur till there is water filled in pipes, because metal is not in contact with atmosphere (oxygen). So whenever the water supply is stopped, due to reasons like maintenance etc, metal start corroding.Note: It can be observed that as supply is again started, first few amount of water is red colored.Thus metal in pipeline corrode only when pipeline is empty. So pipelines in IIT does not corrode very soon. But the pipelines in Kanpur City corrode very fast. The reason is quite obvious. They remain empty for longer periods. Corrosion in RCC structures can occur, because of voids remained in the structure. Moisture will collect in these voids, air is also there, and the combination of two will lead to corrosion. In some cases like the pipes used in the shower pool in front of the PK Kelkar library, the metal is exposed to air in presence of water. Severe corrosion is observed in this case, even in the presence of regularly maintained protective layer of paint. In this case, there are also bio-organisms present on the surface of metal, which lead to crevice corrosion of the metal. In some cases, the underground pipelines corrode very fast and sever. A two or three weeks ago there was a maintenance work going on in VH. There one of the pipelines under the garden was severely corroded. It was no more than a paper sheet remained. The reason was not proper care for corrosion was taken at the time of installation and this region was very much prone to corrosion, due to very high moisture content. So the metal corroded severely in 5-7 years only. Galvanic corrosion:Galvanic corrosion may be the problem in the pillars used for electric power supply, where two different metals come in contact. Here stray currents may also be the reason. Stre...
