USCG urges for attention during testing CO2 systems

The United States Coast Guard recently issued a Safety Alert, detailing two inspections where USCG Marine Inspectors witnessed that the testing and maintenance of carbon dioxide (CO2) systems resulted in serious safety threats that almost led to loss of lives.

In view of this, the USCG is reminding owners and operators that CO2 system inspection, testing, and maintenance requires thoughtful planning and risk mitigation efforts to prevent such events from happening.

In particular, in the first instance, the vessel’s chief mate and a Coast Guard inspector were testing the fire detection system. The mate and inspector went to the vessel’s hydraulic equipment room and the mate stood on a spare parts box in order to apply a heat gun to the heat actuator. The CO2 subsequently discharged directly above their heads and filled the room. The mate was overcome by the CO2 release and had to be revived by CPR after being pulled out of the space unconscious.

The problem was that the mate directed the heat to a “heat actuator” and not a “heat temperature transmitter.” The  difference between these components is substantial. The detector is connected by wires to the monitoring system on the bridge while the release actuator directly connects to its local CO2 system through tubing. The heat actuator when heated creates a slight pressure in the tubing immediately activating the pneumatic control head of the CO2 bottle, releasing CO2 into the space without delay or warning.

Crewmembers were unfamiliar with the vessel’s system and had not referred to the associated manuals. Thus, their testing of the system was conducted without an understanding of the impacts of their actions, placing them and the Coast Guard inspectors at risk.

In a second unrelated event, an inspection for certification involving four inspectors was taking place while technicians were working on the CO2 system. A Coast Guard inspector in the machinery space was told that CO2 technicians were going to release the CO2, which was not part of the planned inspection. He was informed that the system became accidently primed for release when the pilot system was activated by a technician in training. As the technician was reconnecting the cable actuated release levers attached to the tops of the bottles, the activation cables remained connected to the levers. When the bottles were moved later in the servicing process, the cable tension increased to the point where the levers were lifted resulting in the release of charged bottles against a closed valve which prevented immediate release into the space.

The technicians ultimately decided they needed to release the entire engine room CO2 system to remedy the situation. They communicated their intentions to the vessel’s engineers, who performed an accountability of all personnel in the space. However, their count was incorrect as they missed a Coast Guard inspector who was still in the engine room. Only after the inspector’s partner realized his associate was missing was another more thorough sweep of the engine room made and the missing inspector found. Even after clearing the engine room the situation remained hazardous as various personnel stood by in the engine control room while the gas was released. After realizing the magnitude of the CO2 being released, the personnel in the control room evacuated to the vessel’s main deck and no further entry was made into the engine room until the fire department ruled it safe for human occupancy.

As a result of inadequate accountability measures and hazard communications, the safety of crew members and a Coast Guard inspector was placed at risk.