Hot works carried out during maintenance in the cable chamber was the most probable cause of the fire at SingTel's Bukit Panjang exchange on 9 October 2013.
This was the conclusion of an independent Board Committee of Inquiry (BCOI) in Singapore, which was assisted by technical consultant Bell Labs and communications consultant Bell Pottinger.
The investigation revealed that the employee who conducted the maintenance works had borrowed an unauthorised blowtorch from a contractor to seal a cable duct at the cable chamber as he did not have a SingTel issued one. Since the flame of the unauthorised blowtorch was almost twice as hot as that of a SingTel issued blowtorch, it caused localised overheating that resulted in a slowburning fire in the cable chamber.
All of this was not detected as the employee neglected to reactivate the fire detection system, which he switched off before starting maintenance works, when he went for lunch, said Committee chairman Bobby Chin to Today.
Shortcomings in fire safety practices unveiled
Chin added that while the fire was "mainly due to human error, the inquiry uncovered shortcomings in fire safety practices in [SingTel's facility] that require immediate rectification."
For instance, the use of lead-based sealants and open flames posed fire risks. In response to this, SingTel will convert all duct seal installations to MCT Systems by end of 2014. Cables will be sealed with flame-retardant PVC instead of polyethylene (PE). In the meantime, SingTel has switched to an alternative method for hot works - it uses a hot air blower without open flames, and enforced a longer fire watch.
The BCOI has also identified a number of areas of improvement in network design and stakeholder engagement. It recommended SingTel to work closely with industry players in the existing three-tier industry structure for fibre services, as well as to collaborate with them on disaster recovery.
The employee is currently suspended with pay while waiting for SingTel management to decide on appropriate disciplinary action, according to The Straits Times.
Simon Israel, chairman of SingTel, said that the company's management has accepted the BCOI's findings and is committed to implementing the recommendations.
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