Broken parapet wall contributed to Boon Lay gondola incident
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A gondola giving way after part of an HDB roof parapet in Boon Lay collapses.
ST PHOTO: SHINTARO TAY
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SINGAPORE - A broken parapet wall contributed to the May 11 incident that saw two workers scrambling out of a gondola left dangling at the 15th storey
In an earlier statement, the Building and Construction Authority (BCA) revealed that there was localised damage on the concrete roof parapet, which partially supported the gondola.
The Ministry of Manpower (MOM) said preliminary investigations revealed that the gondola tilted as the parapet wall, on which its overhead support was installed, had broken.
Investigations are ongoing.
After the support came loose, one of the workers was forced to climb out of the lopsided gondola onto a ledge on the 15th storey of Block 199 Boon Lay Drive, before he was rescued by Singapore Civil Defence Force officers.
The other worker managed to climb into a unit on the 14th storey.
MOM said gondolas, or suspended scaffolds, are commonly used as temporary platforms for workers to carry out work at heights on the exterior of buildings, adding that there are currently about 5,000 gondolas in use.
“There were two workplace accidents involving the use of gondolas in 2022 and one in 2023 to date,” it added.
BCA engineers found only localised damage at the block and determined that the building remains structurally safe.
HDB said works carried out on HDB buildings involving the use of gondolas must be done in accordance with the Workplace Safety and Health (Scaffolds) Regulations.
“For example, the gondola anchorage system must be designed by a professional engineer (PE) who is required to conduct loading checks to ensure that the supporting structure can bear the weight of a gondola.
“The PE is then required to inspect and ensure that the gondola system is erected and installed in accordance with this design, and that it has been properly anchored to the building before use,” added HDB.
A spokesman for the West Coast Town Council had earlier said that the support system for the gondola was set up by the contractor, Ban Contract Services, for workers to stand on to paint the facade of the building.
The Straits Times understands that works there have not resumed.
Workers who operate gondolas must attend a specific course for suspended scaffolds, in addition to a construction workplace safety and health course, said a spokesman for the Singapore Contractors Association Limited Academy.
They must also don basic personal protection equipment including safety harness, helmet and safety shoes, and the gondolas must be inspected by a PE at least once every six months.
Before a gondola is distributed to construction companies for use, multiple engineers are tasked to assess its structure and safety.
Two workers were taken to hospital on May 11 morning after a gondola tipped sideways from the top of a 15-storey HDB block in Boon Lay Drive.
PHOTO: SHIN MIN DAILY NEWS READER
Engineer Chong Kee Sen, emeritus president of the Institution of Engineers, Singapore, said that a mechanical engineer has to conduct a load test to verify that the gondola system is capable of withstanding the intended loads.
He also has to ensure that the gondola mechanism is in good working condition.
Aside from testing the gondola mechanism, engineers also need to test the structures where the anchor, which holds the platform, is placed. This job is handled by a structural engineer.
Engineer David Ng, the institution’s honorary secretary, said that rooftop structures for anchoring gondola support must be designed and checked for loading of the anchor by a structural engineer.
He said that loads have to be added onto the anchor points prior to construction to test its strength.
“Before the commencement of a construction project, a structural engineer also reviews design and construction plans to ensure that the gondola system is capable of withstanding the intended loads,” said Mr Ng.
An example of a properly secured gondola on the rooftop of JEM mall.
PHOTO: INSTITUTION OF ENGINEERS, SINGAPORE
The incident in Boon Lay occurred towards the end of the heightened safety period, which MOM imposed from Sept 1, 2022. was extended to May 31, 2023.
The safety period was introduced following a rise in workplace deaths in 2022.
Although the period saw a decline in workplace fatality rates, the major injury rate per 100,000 workers increased to 19.2, a 2.4 increase from before the safety period was introduced.
Correction note: In an earlier version of the story, we said that preliminary investigations by BCA revealed that the overhead support of the gondola came loose when the parapet wall on top of the HDB block was damaged. It was MOM that drew the conclusion. The Institution of Engineers was also wrongly referred to as Institute of Engineers. It has been corrected. We are sorry for the errors.
