Investigation reveals cause of fire incident on world’s 1st LH2 carrier Suiso Frontier

The Australian Transport Safety Bureau (ABTS) has completed its investigation into a fire incident aboard the world’s first LH2 carrier Suiso Frontier that occurred on January 25, 2022 on its maiden voyage.

The ABTS investigation found that the failure of an improperly installed electrical solenoid valve resulted in a brief propagation of flame from the vent stack of a liquid hydrogen carrier gas combustor

As a reminder, the Suiso Frontier, built as a prototype ship to evaluate the technical aspects of transporting liquid hydrogen (LH2) by sea, departed Kobe, Japan, on December 25, 2021 carrying 55t LH2 and arrived at the Port of Hastings, Victoria January 20, 2022 to load additional cargo before returning to Kobe.

After the LH2 was loaded in Hastings on 24 January 2022, the ship was still at anchor on the evening of 25 January when the gas control system malfunction occurred.

A worker on board the ship observed a momentary yellow gas flame spreading from the vent shaft of the gas combustion unit onto the ship’s deck. There was no subsequent fire or explosion, and no injuries or damage were reported.

Nevertheless, on February 25, 2022, the Suiso Frontier returned to Kobe, Japan from Hastings and delivered the world’s first cargo of liquefied hydrogen to the country.

Following the incident, ABTS launched an investigation which has now found that the gas incinerator’s air blower damper actuators – which regulate the airflow into the unit – were fitted with direct current (DC) electric solenoid valves that were incompatible with the 230V AC power supply from the GCU controller.

“During the approximately 400 hours of operation prior to the event, the solenoid valves were exposed to conditions for which they were not designed,” ATSB chief commissioner Angus mitchell said.

“When one of these solenoid valves failed, the operating fan exhaust shutter closed. As a result, the temperature of the gas combustion unit increased, eventually leading to flames escaping from the unit’s vent stack.”

In addition to installing the wrong solenoid valve, the ATSB determined that the gas incinerator was not equipped to detect failure of the valve and subsequent closure of the damper.

In response to the incident, the manufacturer of the gas firing system, Saacke, installed limit switches on each air outlet flap to monitor the flap position.

In addition, the system’s control logic has been programmed to stop the unit if an error is detected.

“The ATSB investigation underscores the importance of ensuring that automated ship operating systems are equipped with safety controls to prevent dangerous consequences in the event of a malfunction,” Mitchell closed.

“The incident also demonstrates the importance of strict manufacturer quality controls to ensure the correct system components are specified and incorporated into the equipment.”