Question

With reference to entry into enclosed spaces onboard:

(a) Define "Enclosed space" and give example of enclosed spaces onboard. (7)

(b) Describe the procedure for testing the atmosphere inside such enclosed spaces. (7)

(c) Explain safety precautions taken prior to entry into enclosed spaces onboard vessel. (6)

Answer 1

Part (a)

An Enclosed Space is defined as any space that is enclosed. An enclosed space has a risk of death or serious injury from hazardous substances or dangerous conditions such as lack of oxygen, toxic gas or other vapour, Limited openings for entry and exit, Unfavourable natural ventilation and is not designed for continuous worker occupancy

Examples of enclosed spaces on-board ship are

Ballast tanks, Fuel oil tanks, Pump rooms, Cargo holds, double bottoms, lube oil tanks, Void spaces, Engine crankcases, BOW Thruster spaces, Battery lockers, Boilers, Cargo tanks, Double hull spaces, Sewage Tanks, Cofferdams, Inter barrier spaces, CO2 rooms, Paint lockers, Fresh water tanks, Spaces affected by chemical spill, Pressure vessels, Gas bottle storage lockers, spaces affected by fire, compressor rooms, duct keels, chain lockers, hollow spaces.

Part (b)

An enclosed space contains lack of oxygen or contains flammable or toxic gases. it is important to take samples at the top, middle, & bottom to locate varying concentrations of gases & vapours. Highly concentrated gases can collected at the top or bottom of a confined space depending on whether they are less or more dense than air. Dilute gases & vapours in the ppm range distribute evenly throughout a confined space. It is important to sample at a distance from the opening because air supply near the entrance can give a false sense of adequate oxygen presence.

Using a gas detector, oxygen level should be checked. It should be 20.9% no Combustible gases or flammable gases should be present.

Part (c)

Prior carrying out the job, tool box meeting should be carried out with all the crew members involved. Discussions to carried out about the hazards of the space and how it can be controlled and how the job can be carried out in a safe manner. The following should also be carried out.

Risk Assessment

Document the hazards and necessary safety measures.
Empty the space if necessary and take steps to prevent the space filling up.
Lock out valves and pumps.
Place notices forbidding their operation.
Secure the space adjacent to other tanks, holds, or pipelines which if not secure could present a danger.

Ventilate

The space to be thoroughly ventilated naturally or mechanically.
Guard any openings against accidental and unauthorised entry.
Test the atmosphere in the space for oxygen content and the presence of flammable and toxic gases or vapour.
Do not enter until the atmosphere has been determined to be safe.

Permit to Work

Complete an enclosed space entry permits to work, confirming that the hazards of the job and of the space have been dealt with.
The atmosphere in the space is safe and ventilated,
The space is adequately illuminated,
An attendant at the entrance has been appointed,
Communications have been established between bridge and entry point, and, entry point and entry party.
Emergency rescue equipment is available at the entrance and there are sufficient personnel on board to form a rescue party.
All personnel involved are aware of the task and the hazards and are competent in their role.

✓ Verified Model Answer (Text Solution)

Prior carrying out the job, tool box meeting should be carried out with all the crew members involved. Discussions to carried out about the hazards of the space and how it can be controlled and how the job can be carried out in a safe manner. The following should also be carried out.