Hong Kong’s lift and escalator safety record failing fatigue test
I refer to the report on the Hong Kong government’s Electrical and Mechanical Services Department saying braking systems on lifts built before 2007 might not be up to scratch (“Doubts cast on safety of city’s older lifts”, May 15).
There is no such thing as a piece of machinery that is too old, as long as we observe the fatigue life of each and every moving part that is subjected to repeated cycles of loading and unloading, to have it replaced before the end of its fatigue life.
More frequent inspection is not of much help because by the time the signs of fatigue failure are noticeable to the naked eye, the failure is so imminent as to fall between inspections.
Their failures could have been pre-empted if they were replaced before the end of their fatigue lives.
A computer can be trusted to do the alerting without difficulty. Otherwise, no matter how frequent the inspections were, even if weekly, the failure would have occurred between inspections, because fatigue failure is usually so imminent as to be within a few days of fatigue life expiry.
The repeated accidents alert us to the unpleasant truth that this 21st century city still uses a primitive hand-to-mouth, run-it-to-the-ground approach to electrical and mechanical appliances.
You could make moving parts that have unlimited fatigue lives, but they would be too bulky to install and too uneconomic to operate.
Peter Lok, Heng Fa Chuen