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The welder on board a container ship was engaged in the cropping and fairing of bent gangway railings and stanchions while vessel was at anchor. The gas storage room on this ship was located in way of the port accommodation ladder area, near the bridge front. Resuming his work after lunch break, he uncoiled the rubber gas hoses from within the storage room, opened the gas valves on the torch and attempted to ignite the flame just outside the door to the gas storage room. With a loud 'whoosh' sound, a large fire started inside the gas storage room. With his path to the accommodation entrance blocked by the flames, he ran forward, hoping to meet the deck crew who were working on the forecastle deck.
Meanwhile, the smell of smoke caused the engine crew, who were preparing to enter the engine room from the upper deck entrance, to come out on deck to investigate. They realised that there was large fire burning on the port side gangway area and immediately informed the bridge by telephone. Fire alarm was sounded and the crew mustered, now joined by the deck crew and the fitter who came down the starboard side deck.
By the time the emergency teams assembled at the site, the fire had melted the rubber hoses and the freely escaping oxygen and acetylene gases fed the fire. With rapid rise in temperature and the excessive internal pressure within the full cylinders, the main valves began leaking, further adding to the flames. Two hose parties attempted to fight the fire from forward and aft, but this required careful aiming, as a direct approach to the gas storage room was impossible, and initially the two water jets caused the two teams to unsight each other. The fire being well established due to the freely escaping gases, the water jets had little effect other than providing boundary cooling and a protective shield for the fire-fighting teams. At intervals, a loud explosion was heard, immediately followed by a fireball, presumably caused by the rupture of the cylinders. For almost the entire duration of the fire, the hose parties were prevented from coming within 6 metres from the fire by heat, smoke and intermittent fireballs.
After about 20 minutes, as the contents of the cylinders were exhausted, the fire began to die out and the hose parties were finally able to enter the burnt out gas storage room and put out the remaining fires, now confined to the control valves of a few cylinders.
Fortunately, apart from burnt paintwork on the port side of the house, and damage to stiffeners and fittings inside the gas storage room, there was no significant damage.
Root cause/contributory factors
- Lack of proper risk assessment and equipment inspection;
- Leaking acetylene hose (the crew member later reported that he had 'bandaged' a few small pinhole leaks and cracks with a bicycle tyre tube and insulation tape);
- Failure to shut main cylinder valves during lunch break;
- Hot work very close to the gas storage room.
Other lessons learnt
- Acetylene leaks from the rubber hose and valves and couplings of oxyacetylene gear must be regarded as an ever-present danger. The sense of smell cannot always be relied upon to provide effective warning. Soap solution may be used to detect leaks.
- Acetylene, being lighter than air, can be expected to spread and form a flammable mixture with air at considerable distances from source.
- Every care must be taken to avoid damage to gas hoses. Hoses must be renewed at the first sign of wear or damage; patchwork repair must never be attempted. Discarded hoses must be put beyond use.
- An appropriately sized 'no flame' zone must be enforced around a gas storage room.
- Operators of oxyacetylene equipment must be briefed on the risks and dangers and a safety training session must be conducted before every use, as part of the permit to work system.
- Contingency plans must be carefully explained and rehearsed before commencing work.
- All control valves must be tightly shut whenever work is paused or completed.
- Hot work must always involve an assisting crew member playing the role of fire watch.
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