SingTel has begun improvements to its cable maintenance system and methods, fire safety protocols and training requirements, following a board committee of inquiry into a fire at an Internet exchange in October.
It has stopped using blowtorches on lead seals, which are in 14 of its 22 exchanges, and plans to switch them all to an alternative that requires no hot works by the end of next year. Till then, it will use hot-air blowers with no open flames to soften the seals.
The seals are used to prevent water and gas leaking into underground cable chambers channelling network cables out to users.
The seals must be heated to be loosened and on Oct 9, a worker in the Bukit Panjang exchange used a non-standard issue blowtorch that was too hot, resulting in the sealant and plastic cable sheaths smouldering undetected for up to an hour.
SingTel has since also instituted a 24-hour fire watch after hot works, up from half an hour before, and now uses handheld thermal imaging cameras to check for hidden fires.
The committee, comprising non-executive independent board members Bobby Chin, Fang Ai Lian and Low Check Kian, also recommended changing the polyethylene plastic cable sheaths to flame-retardant PVC (polyvinyl chloride), and tightening access to the cable chambers.
They recommended installing automatic fire suppression systems which were previously placed only in spots with electrical or heat-generating equipment. Cable chambers had only handheld fire extinguishers.