Two thermoelectric generators help test the response time of the fire alarm system.
As designed, aside from automatically detecting fire and putting it out as soon as possible, the system could divide the affected area into smaller zones to ensure accurate management.
Built at the cost of VND95 billion ($4.1 million) in 2021, the automatic firefighting system is the first to be set up in a tunnel in Vietnam.
To test the system, the tunnel had been closed to traffic from 11 p.m. to 4 a.m. on three nights of Oct. 23, 24 and 25. The temporary shutdown only affects cars and trucks as normally, motorbikes are not allowed in the tunnel during this period.
Workers check the system before trialing it. The system comprises a water pump, water pipes, and sprinklers.
An engineer checks the operating sprinklers.
"The ability to automatically detect and put out fire at an early stage will make evacuation easier and protect the tunnel structure," he said.
The Thu Thiem tunnel, built in 2011, is the only river tunnel in Vietnam and the longest of its kind in Southeast Asia.
It is 1.49 km long, 33 meters wide and nine meters high and has six lanes and two emergency exit lanes.
Some 47,000 cars and up to 270,000 motorbikes use the tunnel every day.
