Entering a space correctly after a fire might take patient but can save lives. Marine Safety Forum have issued a safety alert involving what was believed to be a fire, extinguished by a fixed fire fighting system, and subsequently entered safely. It is an offshore incident but is equally applicable in other circumstances.
Says the safety flash: Whilst travelling from overside cover a rescue boat engine suffered a bearing failure in the alternator; causing the belt to be shredded and thrown from the flywheel. The engineer stopped and isolated the engine before removing “all” of the remains of the belt from the engine space.
Two hours later, the fire detection system covering the engine spaces alarmed in the wheelhouse, a strong smell of burning permeated the craft, and smoke could be seen over the port and starboard engine space CCTV cameras.
The commander, called for engines to be stopped, the remote fuel stops to be pulled, the fire flaps closed, and the fixed fire-fighting system to be deployed.
The commander waited for a suitable amount of time to elapse – thirty five minutes, though different circumstances may require a greater period – before permitting entry, and ensured that the space was adequately ventilated and confirmed free from fire or any potential sources of re-ignition over the CCTV camera system. Only after this was a controlled entry made.
It was subsequently discovered that there had been no fire, and that the smoke and smell of burning was from a small section of the thrown travel power belt which had become trapped between the rotating flywheel (driven by the motor of the engine) and the two main alternator belts. The resultant friction resulted in copious amounts of smoke.
1) The commander and his crew reacted well to a situation they had every reason to believe was considerably more serious and deployed the PyroGen fixed fire-fighting system. The commander made a conscious decision to wait for thirty five minutes and ensured that the space was adequately ventilated from smoke fumes and PyroGen before making a controlled entry. In addition, he reminded his crew that it was necessary to wait.
2) Only once the Commander was satisfied that there was little chance of re-ignition – at this point the crew were still working under the assumption that they were dealing with a fire – did he open the forward engine room door to allow oxygen into the space and promote ventilation prior to entry.
1) Each boat to be provided with a small, portable, BA set.
2) Each boat to be provided with particle masks suitable for an environment where airborne PyroGen particles are present.
Actions to be Taken Onboard:
1) Remember that just because a fire appears to have been extinguished the risk of re-ignition remains as soon as oxygen is reintroduced to the atmosphere. It is therefore necessary to leave
sufficient time for the space to cool adequately before entry is made. It should be noted that a definitive time cannot be given for every eventuality.
2) Airborne particles of fixed fire fighting systems can cause damage to the respiratory tract, and carbon monoxide from combustion may be present. It is therefore necessary to promote adequate ventilation prior to making a controlled entry.