When dealing with liquefied petroleum gas (LPG) tankers, safety is non-negotiable. The volatile nature of LPG, combined with its propensity to vaporize under certain conditions, makes stringent safety measures a necessity. During a recent inspection conducted by our project team, ship crew, and a third-party surveyor onboard an LPG tanker, we encountered a situation that underscored the importance of vigilance, expertise, and immediate action.

Identifying the Issue: Fluctuating LEL Readings

The inspection revealed fluctuating Lower Explosive Limit (LEL) readings in multiple areas onboard, signaling the presence of potentially hazardous gas concentrations. These readings were a clear red flag, requiring immediate action to prevent any escalation. Here’s how we tackled the situation step by step:


Key Measures Implemented

1. Pressure Relief Valve Opening

The chief officer was instructed to open the pressure relief valves on all three tanks (six in total). This step was crucial to release any gas buildup inside the tanks, reducing the risk of explosive concentrations and allowing the residual gas to dissipate safely into the atmosphere.

2. Enhanced Ventilation

To ensure proper airflow and reduce vapor accumulation, an additional compressor with three pneumatic exhausts was deployed. This setup maintained continuous ventilation around the pressure relief valves, clearing residual gases and ensuring a safer working environment.

3. Controlled Work Permits

 

Although limited hot work permits were granted, operations on the main deck and LPG-affected areas were strictly restricted. By limiting potential ignition sources, we minimized the risk of incidents during ongoing inspections and repairs.

Observations: Cloudy Vapors from LPG Tanks

During our operations, we noticed cloudy smoke or vapor escaping from an LPG tank nearing depletion. This phenomenon is common and occurs due to:

  • Vaporization: LPG, a mixture of propane and butane, transitions from liquid to gas as pressure drops. This process often produces visible vapors.
  • Condensation: As the gas vaporizes, it cools, condensing water droplets in humid air to form a mist or fog.

While these vapors are a natural occurrence, they carry flammable properties and must be handled with utmost caution.

Best Practices for Handling Cloudy Vapors

To manage such situations safely, we adhered to the following protocols:

  1. Evacuate the Area: We ensured all personnel stayed clear of hot or cold work zones, confined spaces, and painting operations near the affected tanks.
  2. Avoid Ignition Sources: Electrical equipment and any spark-producing operations were restricted to prevent ignition.
  3. Ventilation with Venturi Blowers: Only venturi blowers were used for ventilation, as electric air blowers are restricted onboard.
  4. Professional Assistance: The EHS third-party surveyor and Trakhees PCFC officers were consulted for guidance and oversight.

Critical Observations and Lessons

 

  • Double Banking Challenges: The vessel’s double banking setup posed limitations for emergency rescues due to unsafe gangway conditions. This highlighted the need for advanced planning to mitigate such risks.
  • VOC Gas Detector Compliance: A VOC gas detector with a range of 0–100 ppm was mandated as per the surveyor’s recommendation, reinforcing the importance of proactive compliance.

Conclusion

Through effective teamwork, clear communication, and adherence to safety protocols, the situation was managed without incident. By ensuring continuous ventilation, restricting ignition sources, and following established guidelines, we successfully mitigated the risks posed by fluctuating LEL readings and cloudy LPG vapors.

This experience serves as a reminder of the critical role that expertise and preparedness play in ensuring safety onboard LPG tankers. At the heart of it all lies a commitment to protecting lives, assets, and the environment, no matter how complex the challenge.