The report is written to head office in a formal style.

Report on injury from boiler blow-back

From: Second Engineer Officer, M.V. [name]

To: Marine Superintendent / Head Office

Subject: Serious injury to a Rating due to "blow-back" from the oil-fired auxiliary boiler, and precautionary measures now taken

Circumstances of the incident

While the auxiliary oil-fired boiler (used for heating/domestic steam and fuel oil heating) was in operation, a fire/flash-like "blow-back" occurred at the boiler, and a Rating who was attending in the boiler room suffered serious injury (burns) from the sudden back-flash/flame/smoke. Blow-back in an oil-fired auxiliary boiler occurs when an accumulation of unburnt oil vapour/gas in the furnace or the flue/combustion chamber ignites suddenly and flashes out through the air openings, the furnace door or the flue, i.e. the flame and products are expelled in the opposite direction to the combustion air flow. Contributory conditions typically are: failure to ensure correct combustion, oil leaking/dripping into the furnace so that unburnt fuel accumulates, a failing/weak ignition, blocked or restricted air supply/furnace door, the presence of residual oil vapour after a failed start, or an obstruction in the flue causing pressure surge. On this occasion the blow-back occurred during normal running/lighting and appeared to relate to a build-up that ignited and vented through the boiler front/furnace door opening.

Immediate action taken at the time: the injured Rating was given first aid and removed to medical quarters and, on medical advice, arrangements were made for shore medical assistance/repatriation as necessary; the boiler was tripped and secured, the casualty zone made safe, and a detailed investigation commenced.

Precautionary measures now taken to reduce the possibility of recurrence

• Emergency shut-down: the boiler fuel supply is immediately tripped by the low-water and flame-scanner safeguards; the furnace is purged for a set period before any re-light, so no unburnt vapour remains.
• Correct lighting-up procedure: enforce the pre-determined, supervised start-up sequence - pre-purge for a timed period with the forced-draught fan running and the damper open, correct air/fuel ratio setting, mandatory warm-up, and a low-fire start with flame confirmation before raising firing rate.
• Instrumentation/safeguards: verify the flame scanner (UV/photo-cell) and low-water cut-out operate correctly and are subject to regular fuel-trip and shutdown testing; fit a correct flame failure lock-out (manual reset) and an automatic high-fire trip.
• Housekeeping/ventilation: keep the boiler front, furnace door and air openings free of obstructions and oil leakage; ensure the burner atomiser is clean so no unburnt oil accumulates; check the flue and soot-blower clear.
• Training and safety: instruct all ratings/engineers in the safe lighting, operating and emergency-stop procedures and the danger of standing near/in front of the furnace and firing; no one to approach the boiler front when lighting or when it is in an unsafe condition; provide personal protective equipment and enforce it; put the procedure in the standing orders and posters.
• Supervision: no auxiliary boiler to be started/altered except by an engineer following the controlled sequence; a competent person to be in attendance during light-up.

The whole matter is being followed up with a full internal report and the necessary notifications to the authorities as required; the boiler is only being restarted after a satisfactory survey and a safe operational check.

Regards,

Second Engineer Officer