One of the most popular tourist attractions in Shanghai is the Oriental Pearl Radio and TV Tower, which offers a magnificent view of the city, particularly after nightfall.

Frank Heinricht, 55, is probably a little unusual in that rather than being attracted mostly by the spectacular views on such a visit, it is the clear glass underfoot 260 meters up in the tower that keeps him preoccupied. His big question: Is it safe?

Heinricht is the chief executive of the German specialty glass maker Schott, and as such his professional interest in glass follows him almost everywhere he goes.