Dangers of entering an enclosed space:
1. Toxic atmosphere
A toxic atmosphere may cause various acute effects including impairment of judgment, unconsciousness and death.
2. Oxygen deficiency Can be lacking for:
Displace of air by another gas
Various biological process or chemical reaction
Absorption of air
3. Flammable or explosive atmosphere
Flammable atmosphere present a risk of fire or explosion. Such atmosphere can arise from the presence of flammable liquid or gas or suspended combustible dust in air inside the enclosed space.
4. The flowing dangers may present too like:
Oxygen enrichment
Flowing liquid or free flowing solids
Excessive heat.
Implementation of “Permit-to-enter” system for entry into enclosed spaces:
- Risk assessment to be carried out by a competent officer as enclosed or confined space entry is deficient in oxygen, making it a potential life hazard
- Risk assessment is one of the core preparation tools for enclosed space entry. It is designed to minimize the possibility of accidents by dealing with every aspect of the entry, identifying the hazards, deciding the control measures and finding alternatives or solutions or means to mitigate the risks. RA should be performed every time before man entry
- A list of work to be done should be made for the ease of assessment for e.g. if welding to be carried out or some pipe replacement etc. This helps in carrying out the work quickly and easily
- Potential hazards are to be identified such as the presence of toxic gases
- Opening and securing has to be done and precaution should be taken to check if the opening of enclosed space is pressurized or not
- All fire hazard possibilities should be minimized if hot work is to be carried out. This can be done by emptying the fuel tank or chemical tank near the hot workplace
- The confined space has to be well ventilated before entering. Enough time should be allowed to establish a ventilation system to ensure that air containing enough oxygen to sustain life is introduced. Ventilation can either be natural or mechanical using blowers.
- vels of the enclosed space, the top, middle and the bottom and through as many openings as possible to obtain a representative sample of the atmosphere in the space. Exposure to even 2 to 5 ppm hydrogen sulphide atmosphere can cause headache, nausea and teary eyes.
- The oxygen content should read 20% by volume. Percentage less than that is not acceptable and more time for ventilation should be given in such circumstances.
- Enough lighting and illumination should be present in the enclosed space before entering
- A proper permit to work has to be filled out and checklist to be checked so as to prevent any accident which can endanger life. A confined space should only be entered with an authorised and issued permit and by a trained and competent person. The permission to work in an enclosed space specifies:
– The location of the work
– The nature and limitations of the work
– Details of the working team and tools to be used
– Potential hazards
– Precautions are taken
– Protective equipment to be used
– Time of issue and its validity
– Agreed communication methods and intervals
– Signature of the person on issuing the permit and on completion of the work
– Signature of the person who is supposed to enter thus confirming he has been advised on the hazards and the precautions to be observed - Permit to work is to be valid only for a certain time period. If the time period expires then again new permit is to be issued and the checklist is to be filled out.
- Proper signs and Men at work signboards should be provided at required places so that person should not start any equipment, machinery or any operation in the confined space endangering the life of the people working
- Duty officer has to be informed before entering the enclosed space
- The checklist has to be signed by the person involved in entry and also by a competent officer
- One person always has to be kept standby to communicate with the person inside the space. Effective communication between the people inside the space and the person standing by is vitally important. The communication system must be agreed and tested. The standby person must, in turn, be able to communicate with the officer of the watch
- The person may also carry a lifeline with him inside
- The person should carry oxygen analyzer with him inside the enclosed space and it should be on all the time to monitor the oxygen content. As soon as level drops, the analyzer should sound alarmed and space should be evacuated quickly without any delay
- No source of ignition has to be taken inside unless the Master or competent officer is satisfied
- The number of persons entering should be constrained to the adequate number of persons who are actually needed inside for work
- The rescue and resuscitation equipment are to be present outside the confined space. Rescue equipment includes breathing air apparatus, spare charge bottles, stretchers, means of hoisting an incapacitated person from the space like a tripod, rescue harness, portable lighting, etc.
- Means of hoisting an incapacitated person should be available
- After finishing the work and when the person is out of the enclosed space, the after-work checklist has to be filled
- The permit to work has to be closed after this
The above-mentioned procedure is extremely important to enter an enclosed space. These points are imperative to risk any crew member’s life while entering a confined space.
It is of paramount importance that enclosed space entry drills are carried out on board. Drills should be realistic and effective and must involve the active participation of all crew members.
Battery Room Safety:
1) The battery room must be properly ventilated and in dry condition.
2) Ventilation fan material should be non- spark material.
3) Inlet duct should be below battery level, and outlet at top of the compartment.
4) Alkaline and lead acid batteries must not be installed in the same room.
5) Use externally fitted light or flameproof light.
6) Prevent usage of naked lamps and avoiding smoking in the battery room.
7) “NO SMOKING” and “NO NAKED LIGHT” notice must be posted.
8) Emergency switchboard must not be fitted in the battery room because of possibility of spark generation due to arcing of the circuit breakers.
9) Cable must be well insulated and well connected.
10) The cell must be fitted to prevent any movement arising from the ship motion.
11) Use insulated material to prevent spark production.
12) Always use insulated rubber gloves, safety goggles while working.
13) The paint used in the battery room and materials for ducting should be corrosion resistant. No metal jugs should be used for filling distilled water inside the batteries.