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Safe Entry into Fuel Oil Storage Tanks – Isolation, Ventilation & Atmosphere Testing

ETO
2nd Mate
MEO Class 2
MEO Class 4
UK Management
Chief Mate

times asked: 50; times asked
questions: 10; questions
last asked: 2026; last asked

The slides, written out

AI-drawn illustration. Simplified to explain the idea, not to scale.

Slide 1 · SafE ENTRY INTO

SafE ENTRY INTO FUEL OIL STORAGE TANKS Verified enclosed-space preparation and inspection workflow for shipboard fuel oil tanks ISOLATE ALL CONNECTIONS DRAIN & REMOVE RESIDUES VENTILATE CONTINUOUSLY TEST ATMOSPHERE OBTAIN ENTRY PERMIT

Slide 2 · STEP 1

STEP 1: ISOLATE, DRAIN & VENTILATE Prepare the fuel oil storage tank before entry 1. ISOLATE ALL CONNECTIONS Suction valve – lock closed & tag Filling line – blank flange or lock shut Overflow line – secure against backfeed Heating coil valves – lock shut & tag out Pneumercator / gauge lines – isolate or cap FILLING LINE OVERFLOW LINE HEATING COIL SUCTION LINE GAUGE LINE DRAIN VALVE 2. REMOVE RESIDUES Pump out remaining oil to shore or storage Strip tank to remove heel Drain water and sludge from bottom drain Collect in containers and dispose as per MARPOL requirements 3. VENTILATE THOROUGHLY Open top manhole (if fitted) and side manhole Use mechanical ventilation (air blower) Ensure duct reaches the bottom of the tank Continue ventilation until atmosphere tests confirm safe entry conditions PREPARATION FLOW OIL REMOVAL ISOLATION VENTILATION Pump out & strip tank Lock, blank & tag all connections Ventilate until safe atmosphere confirmed

Slide 3 · STEP 2

STEP 2: VERIFY SAFE ENTRY CONDITIONS Test the atmosphere and issue the enclosed space entry permit ATMOSPHERE TESTING OXYGEN Approximately 20.9% by volume OK FLAMMABLE GAS Less than 1% of LFL / LEL OK TOXIC GASES Check for: • H2S (Hydrogen Sulphide) • CO (Carbon Monoxide) • Other cargo-specific hazards OK ATMOSPHERIC CONDITIONS Conditions must be stable for safe entry OK IMPORTANT Re-test atmosphere: • Before entry • After any interruption • If conditions change USE A CALIBRATED MULTI-GAS DETECTOR Ensure instrument is calibrated and functioning properly. ENTRY PERMIT MUST INCLUDE Tank identification Date and time Atmospheric test results with time Isolation status Ventilation status Names of persons entering Name of standby person Permit validity period (shall not exceed 8 hours unless specified by approved procedures) Emergency and rescue arrangements Authorizing officer signature ENCLOSED SPACE ENTRY PERMIT APPROVED Tank ID : Date / Time : Last Test : Valid Until : Authorized By : Authorizing Officer

Slide 4 · STEP 3

STEP 3: ENTER, INSPECT & RESTORE Follow safe entry practices, complete the inspection and restore the tank to service BEFORE ENTRY Standby person stationed outside the tank Rescue equipment and breathing apparatus ready Lifelines and harness prepared Communication (radio / voice signals) established Portable lighting and tools checked DANGER PERMIT REQUIRED CONFINED SPACE DO NOT ENTER DURING ENTRY Wear appropriate PPE Carry and monitor personal multi-gas detector Maintain continuous ventilation Work under constant observation and communication Evacuate immediately if alarm activates or conditions deteriorate AFTER INSPECTION Close the entry permit Remove isolation locks, tags and blanks Close and secure all manholes with gasket Restore all lines and valves to normal configuration Refill tank to service level and check for leaks Record the operation in engine log and oil record book NO ENTRY WITHOUT ISOLATION, VENTILATION, TESTING, PERMIT AND RESCUE READINESS. RESCUE EQUIPMENT AT ENTRANCE Breathing Apparatus Lifeline & Harness First Aid & Oxygen Resuscitator Rescue Winch / Tripod Explosion-proof Lighting Communication Device

In exams

Asked 50 times across 10 different questions, most recently in 2026. Asked most in ETO (30), 2nd Mate (8), MEO Class 2 (4), MEO Class 4 (4).

Drafted by SailR from our daily lessons. AI-drawn illustration. Simplified to explain the idea, not to scale. Last updated 19 Oct 2026.

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