Enclosed space entry procedures involve assessing risks, issuing permits, conducting toolbox meetings, testing atmospheres, using gas monitors, communicating with those on watch, having safety equipment available, maintaining ventilation, and evacuating if conditions deteriorate. Additional precautions are required when atmospheres are unsafe, including only entering if essential, wearing breathing apparatus and rescue harnesses attached to lifelines, and having hoisting equipment ready in case of emergency.

1. marineprohelp.com
One Answer:
Enclosed space entry procedures
What is the procedure for entry into enclosed spaces?
Enclosed Space entry procedures described in Company SMS and differ
from company to company.
Below are common key points:
The space should be thoroughly ventilated throughout.
An ‘Enclosed Space Entry Permit’ must be issued before entry.

2. Risk Assessment must be conducted and all risks and hazards identified and controlled down to the
acceptable maximum.
Toolbox meeting must be conducted to familiarize all participants with the task.
Entry List should be filled in and placed at the tank/space entrance
The space should be tested for sufficient oxygen, that it is free of hydrocarbons and toxic vapors.
Entry team must carry portable gas analyzer to constantly monitor the atmosphere in the space
The officers on watch, on the deck, in the engine room, or the cargo control room should be informed,
as necessary, of any space that is to be entered so that they do not, for example, stop fans, start
equipment or open valves by remote control, close escape doors or pump cargo or ballast into the space
and appropriate warning notices should be placed on the relevant controls or equipment. Where
necessary pumping operations or cargo movements should be suspended when entry is being made into
a dangerous space.
All necessary safety equipment should be readily available. BA, safety lines etc.
At least one man should be standing by at the top of the tank during entry.
Ventilation must be maintained at all times with personnel inside the space.
When opening the entrance to a dangerous space care should be taken
to avoid the effects of a possible release of pressure or vapor from the
space.

3. Space should be isolated and secured against the ingress of dangerous
substances by blanking off pipelines or other openings or by closing valves
or by removing and blanking off a section of pipe. Valves should then be tied
or some other means used to indicate that they are not to be opened.
If necessary, space should be cleaned or washed out to remove as far
as practicable any sludge or other deposit liable to give off dangerous
fumes.
Space should be thoroughly ventilated by either natural or mechanical
means to ensure (by testing) that all harmful gases are removed and no
pockets of oxygen deficient atmosphere remain.
Compressed oxygen should not be used to ventilate any space.
Testing of a space should be carried out only by persons trained in the
use of the equipment.
Testing should be carried out before entry and at regular intervals
thereafter. If possible the testing of the atmosphere before entry should be
made by remote means and the testing carried out at different levels.
Identifying Potential Hazards
Oxygen Deficiency

4. If an empty tank or other confined space has been closed for a time the
oxygen content may have been reduced due to the oxygen combining with
steel in the process of rusting.
Lack of oxygen may occur in boilers or other pressure vessels
particularly where oxygen absorbing chemicals have been used to prevent
rusting.
Depletion of oxygen may occur in cargo spaces when oxygen absorbing
cargoes, are or have been carried.
Oxygen deficiency can also occur in cargo holds e.g. when carrying ore
concentrates even though the hatch covers have been removed and the
discharge of cargo has commenced.
After discharge of volatile cargoes, sufficient vapors may remain in tanks
to cause oxygen deficiency.
Hydrogen may occur in a cathodically-protected cargo tank used for
ballast. Pockets of hydrogen may exist in the upper parts of the
compartment, displacing the oxygen (as well as creating a possible
explosion hazard).

5. If carbon dioxide, steam or other fire extinguishing chemical has been
discharged to extinguish or prevent a fire, the oxygen content of the space
would be reduced.
The use of inert gas in the cargo tanks of tankers and gas carriers or in
the inter-barrier spaces of gas carriers results in only minimal amounts of
oxygen being present.
Toxicity Of Oil Cargoes
Hydrocarbon gases are flammable as well as toxic and may be present
in fuel or cargo tanks which have contained crude oil or its product.
Hydrocarbon gases or vapors may also be present in pump rooms and
cofferdams, duct keels or other spaces adjacent to cargo tanks due to the
leakage of cargo.
The components in the vapor of some oil cargoes, such as benzene and
hydrogen sulfide are very toxic.
Toxicity Of Other Substances
Cargoes carried in chemical tankers or gas carriers may be toxic.
There is the possibility of risk of leakage from drums of chemicals or
other packages of dangerous goods where there has been mishandling or
incorrect stowage or damage due to heavy weather.

6. The trace components in the inert gas such as carbon monoxide, sulfur
dioxide, nitric oxide and nitrogen dioxide are very toxic.
The interaction of vegetables or animal oils or sewage with sea water
may lead to the release of hydrogen sulfide which is very toxic.
Hydrogen sulfide or other toxic gases may be generated where the
residue of grain or similar cargoes permeates into or chokes bilge pumping
systems.
The chemical cleaning, painting or the repair of tank coatings may
involve the release of solvent vapors.
Procedures And Arrangements Before Entry
Access to and within the space should be adequate and well illuminated.
No matches, welding or flame cutting equipment, electrical equipment or
other sources of ignition should be taken or put into the space unless the
master or responsible officer is satisfied that it is safe to do so.
In all cases, rescue and available resuscitation equipment should be
positioned ready for use at the entrance to the space. Rescue equipment
means breathing apparatus together with fully charged spare cylinders of air,

7. lifelines and rescue harnesses and torches or lamps, approved for use in the
flammable atmosphere, if appropriate. A means of hoisting an incapacitated
person from the confined space should also be readily available when
appropriate.
The number of persons entering the space should be limited to those
who actually need to work in the space and who could be rescued should an
emergency occur.
At least one attendant should be detailed to remain at the entrance to
the space whilst it is occupied.
A system of communication should be agreed and tested by all involved
to ensure that any person entering the space can keep in touch with the
person stationed at the entrance. The communication between the link
person at the space entrance and the party inside the space must be tested
on a regular basis.
A system of communication should be established between the
attendant at the entrance to the space and the officer on watch.
The extent to which the use of breathing apparatus or life or rescue
harnesses would cause any difficulty of movement within any part of the

8. space, or would cause problems for any incapacitated person who had to be
removed from the space, should also be examined.
Lifelines of rescue harnesses should be long enough for the purpose
and be easily detachable by the wearer should they become entangled, but
should not otherwise come away from the rescue harnesses.
A "Block and tackle" should be mounted adjacent to the space entrance,
to be used in the removal of a casualty, in the event of an accident.
Procedures And Arrangements During Entry
Ventilation should continue during the period that the space is occupied
and during temporary breaks. In the event of a failure of the ventilation
system any persons in the space should leave immediately.
The atmosphere should be tested periodically whilst the space is
occupied and persons should be instructed to leave the space should there
be any deterioration in the conditions.
If unforeseen difficulties or hazards develop, the work in the space
should be stopped and the space evacuated so that the situation can be
reassessed.

9. If a person in a space feels in any way adversely affected he should give
the pre-arranged signal to the attendant standing by the entrance and
immediately leave the space.
When available a rescue harness should be worn to facilitate recovery in
the event of an accident.
Should an emergency occur the general (or crew) alarm should be
sounded so that the back-up is immediately available to the rescue team.
Additional Requirements For Entry Into A Space Where The
Atmosphere Is Suspect Or Known To Be Unsafe
If the atmosphere is considered to be suspect or unsafe to enter without
breathing apparatus, then the space should only be entered if it is essential
for testing purposes, the working of the ship, for the safety of life or for the
safety of the ship. The number of persons entering the space should be the
minimum compatible with the work to be performed.
Breathing apparatus should always be worn. Respirators cannot be
used.

10. Where remote testing of the space is not reasonably practicable, or
where a brief inspection only is required, a single air supply may be
acceptable provided a prolonged presence in the space is not required and
the wearer of the breathing apparatus is so situated that he can be hauled
out immediately in case of emergency.
Rescue harnesses should be worn. Wherever practicable lifelines should
be used. Lifelines should be attended by a person stationed at the entrance
who has been trained how to pull an unconscious person from a dangerous
space. Where the dangerous space to be entered requires the possible use
of hoisting equipment to effect rescue, arrangements should be made to
ensure that persons would be available to operate it as soon as necessary.
When appropriate, portable lights and other electrical equipment should
be of a type approved for use in a flammable atmosphere.
Should there be any hazard due to chemicals, whether in liquid, gaseous
or vapour form, coming into contact with the skin and/or eyes then protective
clothing should be worn.