SINGAPORE - The collapse of the ventilation duct in a Nex mall cinema was due to "a significant amount of water" accumulating in the insulation material surrounding the duct.
The investigation findings were released by the Building and Construction Authority in a statement on Monday (Dec 7), following the incident at a Shaw Theatres cinema hall on Aug 30 that left two moviegoers injured.
The water accumulation was a result of "unforeseen excessive condensation over a sustained period", and its weight had overloaded the air-conditioning and mechanical ventilation (ACMV) dropper duct.
This overloaded the brackets supporting the ACMV duct, causing it to give way.
The acoustic material surrounding the duct typically serves to regulate the surface temperature around the duct to prevent water from forming due to condensation, and to insulate the noise caused by air travelling through the duct.
Checks on other cinemas' ACMV systems and ducts had found no such excessive condensation, said BCA.
A spokesman for Nex, which is owned and managed by Gold Ridge, said in a statement on Monday that it will “continue to support and work closely with (its) tenant, Shaw Theatres, throughout the course of rectifications for the planned reopening of their premises next year”.
It did not say if checks on other ACMV ducts in the building will be conducted.
Shaw Theatres said on Monday that it will work with its landlord Gold Ridge to carry out the necessary rectification works to ensure that such an incident will not happen again. The works will be supervised by a professional engineer the building owner has appointed, as instructed by BCA.
It is targeting to reopen its Nex cinema outlet in April next year.
Building owners are responsible by law for the maintenance of their buildings, including interior fixtures.
Shaw Theatres had also conducted inspections at its six cineplexes following the incident, and all were found to be safe.
Similarly, Golden Village cinemas said it had conducted an additional round of inspection and maintenance checks with BCA officers, after recommendations from the authority.
It also has an ongoing monthly maintenance schedule for all its cinemas to be inspected by professional ACMV contractors.
BCA said it will be issuing an advisory to the building owners and the industry on the importance of regular maintenance and to share good practices for the design and installation of ACMV systems.