Corrosion in India
The map describing corrosion patterns in India shows macroscopic differences between areas, with coastal regions being the most severe. The corrosion map of India was prepared by the Corrosion Advisory Bureau, Metals Research Committee (Council of Scientific & industrial Research) Jamshedpur and the book was edited by K.N.P.Rao and A.K.Lahiri. The map was drawn on the basis of data collected over the 5 year period from 1963 to 1968 and published in 1970. The published booklet can be purchased by contacting the Director, National Metallurgical Laboratory, Jamshedpur-831 007. (The Map of India makes the News)
CHENNAI: Here's more bad news for the already wobbly Chennai real estate market: the city's buildings may be more corrosion-prone and hence structurally less stable than they seem, a recent study done by the Central Electrochemical Research Institute (CECRI), Karaikudi, says. (reference)
As per the updated corrosion map of India drawn by CECRI scientists, Chennai is the second most corrosion-prone city/town in the country, thanks to its ever-increasing vehicle population and its coastal location. The first place goes to Sriharikota on the AP coast.
What this means is that those buildings in the city which have not been made specially corrosion-proof (or for that matter, even those vehicles which have not received an extra coat of anti-corrosion paint) might be in for considerable trouble.
The results of the study, done by a team of scientists headed by Dr N Palaniswamy, Deputy Director, State Corrosion Protection Committee, CECRI, has a surprise finding: non-coastal Mettupalayam in Tamil Nadu was found to be among the five most corrosion-prone places in the country.
The study is part of an ambitious effort by CECRI to update the country's corrosion map - 35 years after it was first drawn up by the National Meteorological Laboratory, Jamshedpur - to enable design engineers and other metal users to go opt for less-corrosion-prone materials.
``Corrosion is a natural impact of atmospheric environments like marine, industrial, urban and rural and affects the structural stability of buildings. The annual loss due to corrosion can be compared with that of other natural calamities like earthquakes and cyclones, only its impact is indirect. Loss due to corrosion has been reported to account for more failures in terms of cost and tonnage than any other environment,'' says Dr Palaniswamy. The overall loss due to corrosion alone amounts to at least 2 to 4 percent of GNP and at least 25 percent of this could be avoided by using appropriate corrosion-control technology.
As a first measure, 33 field stations were set up throughout the country in places like Kolkata, Bhubaneshwar, Vishakapatnam, Sriharikotta, Manali, Chennai, Pondicherry, Nagapattinam, Mandapam, Tuticorin, Kanyakumari, Kochi, Mangalore, Mormogao, Goa, Mumbai, Mettupalayam, Bhopal, New Delhi, Chandigarh and Port Blair. Nineteen of these locations lay on the coast and 14 were inland.
Metal panels of different materials like mild steel, zinc, galvanized iron and aluminium were exposed to the air and annual corrosion rates in millimeters per year (mmy) were determined in correlate with atmospheric pollutants and climatic factors.
Based on the findings, three categories were drawn up: extremely corrosive (above 0.2mmy), corrosive (below 0.2 mmy) and moderately corrosive. While Sriharikotta recorded 1.6mmy, Chennai touched 0.5 mmy, Mormogao 0.45 mmy, Mettupalayam 0.3mmy and Port Blair 0.38 mmy.The mild steel panel at the Chennai naval base, for example, was found to have decreased in size from 2.5mm to 0.5mm in just eight months. Under the corrosive category fell Manali, Mangalore, Kakinada, Mandapam, Tuticorin and Kochi.
``Normally it is only coastal cities that are prone to corrosion. In the case of Mettupalayam, though it is considerably inland, it was found that a combination of rainfall, relative humidity and industrial pollution had been its bane,'' says Dr Palaniswamy, adding that it contains a warning for other industrialised zones too.
So how does one offset losses due to corrosion? More corrosion-resistant alloys need to be developed and vehicles need more anti-corrosion coatings.
New structures should either use more non-ferrous materials or go in for anti-corrosion coatings like cement polymer composite coat or inhibited cement slurry coat. The technology for the former is available with CECRI and its use has already been made mandatory for constructing bridges in Maharashtra. The second has been used in the construction of the Pamban bridge in Tamil Nadu.
Air Pollution in India
Regulatory reforms aimed at improving the air pollution problem in cities such as New Delhi have been quite difficult to implement, however. For example, India's Supreme Court recently lifted a ruling that it imposed two years ago which required all public transport vehicles in New Delhi to switch to compressed natural gas (CNG) engines by April 1, 2001. This ruling, however, led to the disappearance of some 15,000 taxis and 10,000 buses from the city, creating public protests, riots, and widespread "commuter chaos." The court was similarly unsuccessful in 2000, when it attempted to ban all public vehicles that were more than 15 years old and ordered the introduction of unleaded gasoline and CNG. India's high concentration of pollution is not due to a lack of effort in building a sound environmental legal regime, but rather to a lack of enforcement at the local level. Efforts are currently underway to change this as new specifications are being adopted for auto emissions, which currently account for approximately 70% of air pollution. In the absence of coordinated government efforts, including stricter enforcement, this figure is likely to rise in the coming years due to the sheer increase in vehicle ownership.
Source: US Energy Information Agency
June 18 2004 - News Bulletin
Scientists who updated the corrosion map of India after 35 years have been taken by surprise as a town in interior Tamil Nadu tops the list. While high corrosion is normally expected in coastal areas, the first phase of the nation-wide survey has shown that Mettupalayam, a town in interior Tamil Nadu state, is one of the five places in the country where corrosion is "extremely severe."
The four other towns in this "extremely severe" category are Sriharikota, Chennai, Marmugoa and Port Blair - all in the coastal region. Mumbai, Mangalore, Kochi and Tuticorin are places where corrosion is "severe" but not "extreme" while Kanyakumari is among the towns where corrosion is the least.
The survey was done by the Central Electrochemical Research Institute (CECRI) in Karaikudi to revise the corrosion map of India first produced in 1968. Over these years a lot of environmental changes have taken place due to industrialization, population growth and increase in motor vehicles, the study said.
In the last 10 years, CECRI scientists collected data from 33 field stations. In the next five years the number will increase to 150 field stations covering the whole country. Because corrosion leads to shorter life for steel structures, the institute says the corrosion data is immensely useful for design engineers.
The government has allotted Rs.18 million for updating the corrosion map. To augment the funds, the institute has solicited funds from pain manufacturers who are expected to benefit from the study.
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