Four glass windows have shattered and fallen from city skyscrapers in the last three weeks, prompting concern over the reliability and safety of Shanghai's 5,000 glass skyscrapers.
Skyscraper owners and managers held the prime responsibility for the glass in their glass buildings, Deputy Mayor Shen Jun announced at a press conference on Wednesday.
"The city government must step up its efforts to prevent such accidents to minimize economic losses as well as injuries to residents," he also said.
A two-meter glass panel wall shattered on July 14 at the Hongqiao Transportation Hub, shooting dangerous shards onto the street below.
Four days later, another exploded at the same location.
Then on Wednesday another glass panel broke on the 19th floor of a commercial building on Longhua Road East on the Bund as the mercury level held over 34 C last week.
No one was injured, but a Shanghai safety expert told the Global Times on Thursday that the incidents highlighted the urgent necessity for authorities to take greater responsibility by setting up comprehensive safety checks on glass quality, especially before the summer and typhoon seasons.
"The glass walls are designed to last 15 to 20 years, and 20 percent of the city's skyscrapers are in urgent need of replacing their glass," said Fang Yuqing, a government purchasing evaluation expert and a member of the Chinese People's Political Consultative Conference Shanghai Committee.
"It's a very costly maintenance project and I urge the government to set up a fund to help property owners carry out replacements."
The rate of exploding glass was about two windows in a 1,000, according to Fang, "too high odds to be ignored" for a metropolis like Shanghai.
"The density of such glass-walled skyscrapers in Shanghai is like no other city on the Chinese mainland," he said.
Property owners should authorize a qualified assessor to examine once a year after the first eight years, according to city regulations.
Those technical standards were only introduced in 1996 when many skyscrapers had already been built, Lu Jinlong, a senior engineer at the Shanghai Academy of Building Research, told the Global Times on Thursday.
"The country's technical standard does not meet that of the World Trade Organization," Lu said.
"Although that does not necessarily mean that the glass walls are of poorer quality than those built by other more developed countries, Shanghai's skyscrapers need more efficient and thorough safety checks to examine the glass walls' quality."
The main reasons for glass exploding were rust and deformation, Lu said, while hard-to-detect internal air bubbles could also result in glass disintegrating after prolonged exposure to sun and strong winds.