An engineer suffered a freezing burn to his hand when there was a leak of refrigerant gas while he was refilling a vessel’s central air conditioning (AC) system. When the job was completed, the engineer closed the proper valves, disconnected the refrigerant gas bottle, and started the motor to check for any leaks in the system. The AC system was up and running at that time.
But the engineer decided – with the AC compressor running – to give one last torque to the valve to once more ensure it was properly torqued. He crouched and placed himself in front of the point of connection to the hose – “in the line of fire”. Unfortunately, he inadvertently opened the valve instead of tightening it further. It is considered likely that the pin of the ratchet wrench had moved to the opposite position and the engineer did not check the direction of the torque.
There was an immediate refrigerant gas leak towards him. He put his left hand on the leak and tried unsuccessfully to close the valve with the ratchet wrench with his right hand. At that moment, a colleague pushed the engineer out of danger and was able to close the valve in a safe manner.
The engineer’s gloves were initially frozen on; once they were off, his hands were placed in running water. He suffered severe second degree freezing burns to both hands. He was treated on board with the telephone guidance of a doctor, and subsequently transferred ashore for hospital treatment.
It was noted that the client was not made aware of the incident by the contractor until the following morning, and therefore the client (operators) emergency response organization was not notified nor mobilized. The on-board vessel crew did not immediately realize the severity of the injury and therefore did not communicate it immediately to the client.
What were the causes of the incident?
Refrigerant gas Freonâ„¢ 404A reaches temperatures of around -46Â°C when it is released (i.e. decompressed).
- Lack of risk assessment and proper preparation:
- there was no proper risk assessment nor job safety analysis (JSA) conducted for the task
- there was no awareness of the dangers involved
- there was no knowledge of the MSDS for this refrigerant gas;
- Line of fire:
- the point from which the leak occurred pointed towards the operator
- the engineer placed himself “in the line of fire” in front of the point of connection to the hose
- there was improper intervention on ‘live’ equipment without proper safety precautions;
- the engineer did not check the torque direction of ratchet wrench before use, therefore he torqued the valve in the wrong direction;
- Personal protective equipment (PPE)
- the engineer was wearing fabric gloves instead of proper thermal protection gloves as recommended in the MSDS
- thermal protection gloves were not available on board nor had the need for them occurred to the company.
- Eleven days in hospital including intravenous medication and surgery to the burnt hands;
- Following discharge from hospital, a further month of physiotherapy before the injured person was fit for work.
- Proper training in job risk analysis, risk assessment and “line of fire” for crews;
- Permit to work (PTW) to become mandatory for work on high pressure equipment;
- Rotate the position of the discharge point of the compressor so as not to point towards workers, and addition of safety/retention valve (Schrader type valves) on compressor discharge lines;
- Provision of proper and specific thermal protection gloves;
- Reassessment of chemicals used on board and their MSDS;
Ensure that client/operator is informed of any and all injuries on board contractor vessels on hire as soon as possible.
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