Using a duplex system of galvanization and paint could have significantly reduced maintenance efforts and costs for the Eiffel Tower.

By Pavan Kaushik

The Eiffel Tower is built of riveted wrought-iron, a material that only lasts if it is painted periodically. From the date Eiffel Tower was built, in 1889, the tower has been painted 18 times, once every 7 years.

Tower Painting

Painting the entire Tower takes 15 months to complete and a mammoth 60,000 kilograms of paint is used for the first coat that cost around $20 million each time – Rs 130 Crore.

Complexity of Work

Amazed at the cost and complexity of the work involved in repainting the tower, where the painters must use hooks, ropes, safety nets and cannot begin painting each day until the morning dew has evaporated; a Dutch corrosion expert recently made a hypothetical calculation of cost savings had the Eiffel Tower been built on galvanized steel.

Benefits of Duplex System

If Eiffel Tower had been hot-dip galvanized and then painted, which is known as a duplex system, any damage to the paint coating will not lead to corrosion as the steel would continue to be protected by the Zinc, which underlies the paint.

Maintenance Requirements

Had the steel used to build the Eiffel Tower been galvanized before painting, only 7 maintenance operations would have been required since 1889, compared to the 18 that have taken place. The first large-scale maintenance of a duplex system normally takes place after about 25 years.

Cost Implications

What does all this mean in terms of cost?

Based on today’s wage and price levels, the duplex system would have further saved at least $10 million in maintenance costs, which is again 50% savings on maintenance.

History of Galvanization

Obvious question would be that did hot-dip galvanization exist when the Eiffel Tower was made. The answer is YES.

About 50 years before the Eiffel Tower was made, in 1836, Sorel in France took out the first of numerous patents for a process of coating steel by dipping it in molten zinc after first cleaning it. He provided the process with its name galvanizing. 1742 is the first recorded history of galvanizing which dates back to when P.J. Malouin, a French chemist, presented to the Royal Academy of Sciences several experiments involving coating iron with molten zinc.