Ventilation systems in many chemical tankers are not built in accordance with IBC code or SOLAS requirements says the Casualty Investigation Unit of Sweden’s Transportstyrelsen, Transport Agency, releasing its report into the overpressure and explosion aboard the chemical tanker Vingatank on 23 February, 2010.
Says STA: “the chemical tanker Vingatank arrived at Brofjorden on the Swedish west coast after a ballast trip from Kristiansand in south Norway. It was very cold with a temperature of 10ºC below zero.
The second officer checked the P/V valves after arrival and the loading of vacuum gasoil started at 20.05 on 22 February.
Just before midnight a high pressure alarm sounded from tank no. 2 port. The OOW shifted the loading over to tanks no. 3 starboard and port. He reset the alarm and ordered the AB to check the P/V valve. The AB saw fumes coming out of the valve which made the OOW think that it was OK to commence loading. The pressure in no. 2 port tank was normal when the loading of the tank started after the first alarm.
After a while there was a second high pressure alarm from tank no. 2 port. Also at this time the AB saw fumes coming out of the P/V valve. The OOW then assumed that the sensor did not work properly.