If the empty or other confined space has been closed for some time, the oxygen content may be reduced by the rusting process. Oxygen deficiency can occur in boilers and pressure vessels where oxygen-absorbing chemicals have been used to prevent rust.
Oxygen depletion can occur in cargo spaces from loads that absorb oxygen, such as oil cake, steel products, scarf, and so on.
Oxygen deficiency can also occur in the load collection, for example during the transportation of ore concentrates, even though the hatch covers have been removed and the load has been dropped.
If CO2 vapor or other fire-fighting chemical is emitted into the room, the oxygen content in that space will be depleted.
TOXIC HAZARDS
There is always the possibility of dangerous fumes from poorly stacked chemical drums.
Damage to rust, scale or sludge from loads of animal, vegetable or mineral origin or water that could cover such substances can lead to the release of toxic or flammable gases.
PREPARATION OF SPACE FOR ENTRY
Care should be taken when opening the entrance to a hazardous area to avoid the consequences of possible release of pressure or steam from the space.
The Seajobs manual of space must be insulated and protected from hazardous substances by clogging of pipes or other openings or shut-off valves. The valves must then be connected or by other means used to prevent accidental operation.
If necessary, the space should be cleaned or washed to remove as much as possible any sludge or other deposits that may remove hazardous vapors. Special precautions may be required when carrying out such work for the reasons already stated.
The space should be thoroughly ventilated by natural or mechanical means to ensure the removal of all harmful gases. Compressed oxygen should never be used to ventilate the space.
Pavement, cargo control and engine room on duty should be informed and warning signs should be placed to warn against accidental use of equipment, valves or ventilation stops, etc. If necessary, pumping work must be stopped when entering a dangerous area.
NO GAS FREE AND SCIENTIFIC KITS
It is emphasized that entry into tanks which are known to be free of gas or oxygen may be permitted only in exceptional circumstances and when there is no alternative. In this extremely dangerous situation, the personnel involved must be well trained in the use of breathing apparatus and be aware of the dangers of removing the breathing apparatus in a hostile atmosphere.
When it is necessary to enter a tank or compartment where it is suspected that the atmosphere contains toxic gas or lack of oxygen or that these conditions may occur during the occupation, the foreman or supervisor should be responsible for the constant supervision of the operation and should ensure:
The master is satisfied that there is no practical alternative to the proposed method of entry and that such an entrance is important for the safe operation of the vessel. The wizard has filled in the security list “Entrance to the closed space”.
Ventilation is provided where possible.
Staff use breathing apparatus and lifebuoy.
The number of persons entering the tank is reduced to a minimum corresponding to the work performed.
Communications and a signal system understandable to the personnel involved shall be provided.
Agreed and
Spare sets of breathing apparatus (and resuscitators, if any) are ready outside the ward, and in case of emergencies, waiting participants are present.
