The chief officer must enter the pumproom to change a valve packing during cargo operations. What safety precautions apply?

A. PUMPROOM SAFETY — CM PROCEDURE: The pumproom is an ENCLOSED SPACE with additional hazards specific to tankers: hydrocarbon vapour accumulation; H2S from crude oil residues; noise; mechanical hazards from running pumps. MARPOL and ISGOTT pumproom entry requirements: (1) ENCLOSED SPACE ENTRY PERMIT: complete a full Enclosed Space Entry Permit — atmosphere testing, standby person, rescue equipment, communication; (2) ATMOSPHERE TEST: test BEFORE entry and at intervals during: O2 (19.5-23.5% safe); HC (below 1% LEL); H2S (below 5 ppm); CO (below 25 ppm TWA). The pumproom is particularly susceptible to H2S accumulation from crude residues and scale; (3) CONSIDER STOPPING PUMPS: if practicable — discuss with terminal whether cargo transfer can be suspended during the pumproom entry. This removes the risk of pump seal failure or hot surface ignition while a person is inside; (4) PERMIT TO WORK (HOT WORK PROHIBITED): changing valve packing is cold work. No hot work (flame, grinder) in the pumproom during cargo operations; (5) SAFETY HARNESS AND LIFELINE: pumprooms often require descent on a vertical ladder. A safety harness with lifeline allows recovery if the entrant collapses; (6) STANDBY PERSON: at the pumproom access — does not enter. Maintains communication. Has SCBA ready; (7) VENTILATION: mechanical ventilation of the pumproom prior to entry; (8) LIGHTING: pumprooms have poor natural lighting. Use ATEX-rated torches (intrinsically safe); (9) COMMUNICATION: radio or voice contact throughout entry; (10) TIME LIMIT: agree a maximum entry time — permit expires after agreed duration.

B. Pumproom entry during cargo operations is prohibited. All pumproom maintenance must wait until cargo operations are complete and the pumproom is gas-free.

C. The chief engineer is responsible for pumproom safety during cargo operations. The Chief Mate has no role in authorising pumproom entry.

D. The pumproom ventilation fans clear hydrocarbon vapour continuously. Entry is safe without additional testing if the ventilation fans have been running.

A. INERT GAS SYSTEM (IGS) — CM KNOWLEDGE: PURPOSE: The IGS prevents flammable hydrocarbon vapours from reaching an explosive concentration in cargo tanks. A hydrocarbon-air mixture is flammable between approximately 1-10% hydrocarbon concentration (LEL to UEL). The IGS keeps O2 concentration below 8% (SOLAS requirement: below 8% O2 by volume) — at this level, the vapour cannot ignite regardless of hydrocarbon concentration. SYSTEM COMPONENTS: (1) SOURCE: combustion gas from the ship's boiler or dedicated inert gas generator (IG generator using gas turbine or diesel exhaust). Typical O2 content of flue gas: 2-5%; (2) SCRUBBER: removes corrosive components (SO2, H2S, soot) from the flue gas before it enters tanks. Water is the scrubbing medium; (3) BLOWER (FANS): propel the scrubbed gas into the distribution main; (4) DECK WATER SEAL: the critical safety device between the blower and cargo tanks. Prevents backflow of hydrocarbon gas to the machinery space if fans fail. Always maintained wet; (5) P/V BREAKER: secondary protection against overpressure/underpressure in tanks; (6) O2 ANALYSER: continuous monitoring of O2 content in the IG supply and individual tanks. PRE-DISCHARGE PROCEDURE: (1) Check O2 content of all cargo tanks — must be below 8% by volume; (2) Ensure IG pressure positive in tanks before beginning discharge (tank pressure > atmospheric); (3) Start IG supply to replace vapour volume as cargo is discharged; (4) Monitor O2 levels throughout discharge; (5) Never open tank in oxygen-enriched atmosphere without gas-free certificate.

B. The inert gas system is only required during cargo tank washing operations. During normal cargo discharge, the IGS can be shut down to save fuel.

C. The inert gas system replaces the cargo in the tank with CO2. The CO2 acts as both a fire suppressant and inert medium during discharge.

D. Once a tank has been inerted prior to loading, the IGS is no longer needed for the voyage. Inert gas remains stable in the tank without continuous monitoring.

A. PRE-ARRIVAL CRUDE TANKER — CM PREPARATIONS: (1) SHIP-SHORE COMMUNICATIONS: make contact with the terminal. Confirm: berth availability; cargo order; hose/arm connection details; cargo plan and loading/discharge sequence; free flow/simultaneous operations restrictions; emergency shutdown procedures; (2) CARGO PLAN: prepare/review the loading or discharge plan — cargo sequence, tank allocation, ullages, API gravity, temperatures, transfer rates; (3) STABILITY: calculate stability at all stages of the cargo operation. Ensure GM remains positive throughout. Identify the critical condition (minimum GM stage); (4) TANK CONDITION: check all cargo tank O2 levels — below 8% required. Note temperature and pressure of cargo and tank atmosphere; (5) MANIFOLD PREPARATION: inspect manifolds — blank flanges removed, drip trays clear, manifold valves operational; manifold pressure rating confirmed compatible with terminal pumps; (6) MOORING PLAN: confirm berth orientation; prepare appropriate mooring lines; (7) PUMPROOM INSPECTION: access pumproom — check bilge level; inspect pump seals; ensure cargo pumps ready for operation; (8) CARGO HEATING: if heated cargo — ensure steam coils operational and steam supply available; (9) DECK EQUIPMENT: cargo deck valves operated (any seized valves to chief engineer); hose handling equipment ready; (10) ISGOTT SHIP-SHORE SAFETY CHECKLIST: complete the ISGOTT pre-arrival section of the Ship-Shore Safety Checklist (Part A — ship's responsibilities) before the terminal vessel inspector arrives; (11) HOT WORK SUSPENDED: ensure all hot work is completed and stopped before entering port limits; (12) EMERGENCY SHUTDOWN: brief the duty officer on the ESD procedure and agree a shore contact name.

B. Pre-arrival preparations are the terminal's responsibility. The vessel's crew only needs to prepare mooring equipment. Terminal inspectors manage all cargo safety checks.

C. The ISGOTT Ship-Shore Safety Checklist is completed after mooring is complete and cargo operations begin. Completing it before arrival is too early.

D. Pumproom checks are only required by the chief engineer. The Chief Mate has no responsibility for pumproom condition or equipment before cargo operations.