$10 chain solves window dilemma
Simple device can stop aluminium frames falling from high-rises and prevent injuries, say inventors
A former space engineer and a university colleague have invented a cheap and simple safety device to prevent aluminium windows from falling from high-rise buildings and injuring pedestrians.
The device is a 25cm stainless steel chain bolted to the window and frame and concealed when the window is closed.
Co-designed by Michael Hung Yau-yan and Ralph Ip Wai-lam, of City University's Department of Manufacturing Engineering and Engineering Management, the chain can hold up to 300kg, or the equivalent of about 16 aluminium windows.
'The materials of our safety-chain device are remarkably inexpensive and the installation distinctly simple,' said Professor Hung, who used to work for the US space agency Nasa.
The designers said they would not apply for a patent for the invention.
'We encourage the Housing Department, the Buildings Department and any individuals to obtain information from us and use it freely,' said Professor Hung.
The cost of the materials for making a safety chain, including the bolts, was less than $10, and installation took less than 10 minutes, the professor said. But he advised householders to hire specialists to install them.
The Housing Department, which commissioned the study, has yet to decide whether to encourage residents to use the device, but a spokesman said a safety chain had been installed in a Kwai Fong Estate household as a test.
The Buildings Department and the Housing Society showed interest in the device.
'We are happy to see it and appreciate the fact that the designers are not applying for a patent,' said Buildings Department chief engineer Leung Siu-man, 'but we need further studies'.
He said the device had passed a tensile test on a new window, but he asked whether it would also work with windows that were 20 years old - such as those that have been falling to the street in ever-increasing numbers.
Housing Society senior manager Li Kin-wan said the device looked innovative and practical, although the society had yet to decide whether and how to use it.
'We are still looking into the causes of the window-falling incidents before coming up with any solution,' he said.
Professor Hung said the pressing problem of falling windows called for a timely solution.
'The designs of most aluminium windows are problematic,' he said. 'I believe the fallen ones that we have seen are just the beginning. It will only be a matter of time before they all fall off.'
He said the safety chain should stop older windows from falling, even though he had yet to conduct specific tests on them due to a lack of time.
Windows with worn hinges or those overloaded with clothes pose a serious threat to pedestrians.
By July 31, 58 windows had fallen this year, compared with 46 for the whole of last year, according to the Buildings Department.
About noon yesterday, a window was blown off a high-level flat in the Foo Yu Building in Castle Peak Road.
The window hit the platform of the building and did not cause any injury. A police spokesman said the flat owner had been reprimanded over the incident.
