1. CONFINED SPACE ENTRY
Helen Verstraelen

2. CONFINED SPACE DEFINITION
Is large enough and so configured that an employee can enter bodily and perform work;
Has limited or restricted means of entry or exit;
Is not designed for continuous human occupancy.
2 categories:
With open top with a dept that will restrict the natural movement of air
Enclosed spaces with very limited openings for entry

3. EXAMPLES Cargo tanks Manholes Chain lockers Fuel tanks Ballast tanks
Double bottoms
Void spaces
IG plant
Pipes
Trenches
Pump rooms
Sewage tanks
Cable trunks …

4. POTENTIAL HAZARDS Flammable atmosphere Asphyxiating atmosphere
Toxic atmosphere
Irritant atmosphere
Mechanical hazards
Communication problems
Entry and exit problems
Thermal effects
Noise and vibrations
Physical hazards

5. FLAMMABLE ATMOSPHERE Arise from enriched O2 atmospheres
Vaporization of flammable liquids
Chemical reactions
Concentration of chemical dust
Flammable gasses are often heavier than air and will seek lower levels
Gasses lighter than air will rise and develop a flammable concentration if trapped above the opening
Byproducts of work can generate explosive conditions
Welding
Combustible dust during cargo operations ( grain, fertilizers, chemicals…)

6. ASPHYXIATING ATMOSPHERE
Normal 20.9% O2 in air
Decreased O2 % can cause:
17%: increased breathing volume and higher heartbeat
14-16%: increased breathing volume, accelerated heartbeat, poor muscular coordination, rapid fatigue, intermittent respiration
6-10%: nausea, vomiting, inability to perform, unconsciousness
<6%: spasmatic breathing, convulsive movements, death within minutes

7. ASPHYXIATING ATMOSPHERE
Reduced O2 level can be the result of:
Consumption of air
Combustion of flammable substances: welding, heating, cutting, …
Bacterial action: fermentation
Chemical reactions: rust formation
Rate of consumption influenced by number of people and the amount of their physical activity working in the space
Displacement of air
Gasses as Nitrogen or CO2 are used to displace air or combustible gases and will result in an asphyxiating atmosphere

8. TOXIC ATMOSPHERE Toxic atmosphere can be caused by:
Manufacturing process
The product stored: ex. removing decomposed organic material from a tank can liberate toxic substances, such as H2S
The operation performed in the confined space: ex. Welding
During cargo operation a mechanical or human error may also produce toxic gases
CO is a hazardous gas that may build up in an space after incomplete combustion of organic materials (wood, coal, gas, oil..) or microbial decomposition of organic matter. Dangerous at 200ppm, fatal at 1000ppm. Can not be tested with a combustible gas indicator, must be tested specifically

9. TOXIC ATMOSPHERE Limit values:
TLV (Threshold limit value): concentration for a healthy person 8 hours a day during his whole working life.
TLV – STEL (Short term limit value): 15 minutes time weighted average, max 4 times a day, min 60 minutes between 2 periods
TLV ceiling: may never be passed

10. MECHANICAL DANGERS
Each piece of mechanical or electrical equipment should be manually isolated before entry into a CS to prevent inadvertent activation
The space should be completely isolated to prevent vapor leaks, flashbacks, …
Closing of valves is not sufficient. Physically disconnection or blanking is necessary. Testing of the blanked or disconnected lines in needed when re-entering gases may re-contaminate the space
Other areas of concern are steam valves, pressure lines and chemical transfer pipes

11. COMMUNICATION PROBLEMS
Communication between the in- and outside of the CS is very important
When visual monitoring of the worker is not possible because of the design of the CS or the location of the entry hatch, a voice or alarm-activated explosion proof type of communication system will be necessary
Suitable illumination of an approved type is needed to provide sufficient visibility for the job

12. ENTRY AND EXIT
The physical limitations of the entry and exit of a CS are directly related to the hazard of the CS
Precautions for safe entry and exit should be taken and standby equipment should be ready for rescue
Consider the following
Type of CF and access to the entrance
Number and size of openings
Barriers in the space
Time required for exiting in case of fire or vapor incursion
Time required to rescue injured persons

13. THERMAL EFFECTS
When the body temperature increases above 38,5°C, workers are less efficient, and are prone to heat exhaustion, heat cramps or heat stroke
Special precautions must be taken in cold environments to prevent frostbite, or hypothermia
Protective clothing for both hot or cold environment will add additional bulk to the worker and must be considered in allowing for movement in the CS and exit time

14. NOICE AND VIBRATION
Workers in CS are exposed to higher sound levels as the sound reverberates on the walls, thus increasing the risk of hearing damage (temporarily or permanent)
Even when it is not intense enough to cause hearing problems, it may still interrupt communication with the standby person at the exit
Whole body vibration may affect multiple body parts and organs
Segmental vibration, appears to be more localized in creating injury to the fingers and hands when using tools as pneumatic hammers or rotary grinders or…

15. ENTRY
The act by which a person intentionally passes through an opening into a permit required confined space.
Any part of the body passing through the opening is considered entry.

16. ENTRANT - SUPERVISOR
Entrant: The crewmember(s) who will physically enter the confined space to perform the work.
Supervisor: The officer responsible for coordinating the entry into the confined space. He is also directly responsible.

17. ATTENDANT
The crewmember who remains outside the confined space and monitors the entrant(s); guards the space against unauthorized entry; warns the entrants of any unusual conditions; and summons the rescue personnel if needed.

18. CONFINED SPACE PERMIT
A Permit-Required Confined Space is confined space that has one or more of the following characteristics:
Contains or has the potential to contain a hazardous atmosphere;
Contains a material that has the potential for engulfing an entrant;
Has an internal configuration such that an entrant could become trapped or asphyxiated; or
Contains any other serious safety or health hazard.

19. EXAMPLE PERMIT

20. EXAMPLE PERMIT

21. CONFINED SPACE ENTRY PROCEDURE
Isolate the space
Ventilate/Inert the space
Conduct tailboard
Complete permit
Test the atmosphere
Enter the space

22. ISOLATE THE SPACE FROM ALL HAZARDS
Close Valves
Double block & bleed,
or blank flange
Empty the Space
Depressurize, vent & drain
Lockout/Tagout Equipment
Electrical sources
Rotating/reciprocating parts
Hazardous materials
Clean residue from the space

23. VENTILATE / INERT THE SPACE
Use mechanical ventilation
Fans or air horns
Ventilate at the rate of at least four (4) volumes per hour
Larger spaces require more ventilation
Make sure air supply is not contaminated
Ventilation air supply must be from fresh air uncontaminated with flammables, toxins, etc.
Inertion is needed when explosive gasses are present

24. TAILBORD BREEFING Entire crew must attend
Attendants, entrants, entry supervisor
Review hazards of entry and work
Review PPE
Review procedure for contacting rescue
verify rescue available
Complete permit

25. COMPLETE ENTRY FORM
Permit must be correctly and completely filled out prior to entry.
Permit must be activated by Entry Supervisor’s signature to be valid.
No entry is allowed without a valid permit.
Permits are valid for up to 12 hours.
When work is completed, permit and tailboard form should be returned to safety.
Cancelled permits must be kept on file

26. TEST THE ATMOSPHERE IN THIS ORDER: Check for Oxygen Content:
At least 19.5% and less than 23.5%
Check for Combustibles:
Less than 10% of the LEL
Check for Toxic Gasses:
Most commonly carbon monoxide (PEL <35 ppm)
or any other hazardous materials as determined by the use of the space.

27. OXYGEN / FLAMMBABILITY TEST
Electrochemical principle. See Toxicity test with CO
Flammability:
Wheatstone bridge or IR: see “gas fires” for principles

28. TOXICITY TEST (CO example)

29. TOXICITY TEST (CO example)
Electrochemical sensors detect gases by measuring the electric that is generated by chemical reactions (oxidation/reduction). The chemical reaction in the case of CO gas generation is :
CO + H2O -> CO2 + 2H+ + 2e-
(Detection principle), carbon monoxide is oxidized on the detection electrode, and hydrogen ions are generated. On the counter electrode, hydrogen ions (equal to the hydrogen ions on the detection electrode) react with oxygen from the air and generate water. The electricity generated by this reaction chain is proportional to gas concentration, thus the gas concentration can be determined by monitoring the generated electricity.

30. TOXICITY TEST Tubes with absorbent material:
Airborne chemicals are trapped onto the surface of the absorbent.
Decolourisation takes place
Gas specific
1 time use. Momentum measurement!!!

31. IMPORTANT NOTICE
Any time a limit is exceeded, no matter what the reason, all personnel shall immediately exit the space, and no others shall enter until atmospheric conditions are returned to safe levels.
THERE ARE NO EXCEPTIONS TO THIS!

32. WHEN PERFORM ATMOSPHERE TESTING
Prior to every entry when the space is vacant;
After a 10 minute ventilation period (if ventilation is necessary);
At least hourly for permit-required confined spaces.
More frequently, if conditions or suspicions warrant.

33. Always test the
air at various levels
to be sure that the
entire space is safe.
Good Air
Poor Air
Good air near the opening does NOT mean there is good air at the bottom!
Deadly Air

34. ENTER THE SPACE
An attendant shall be posted near the entrance for the duration of the work. He shall be in constant communication with the entrants while the job is in progress.
All entrants shall sign the sign in log when entering the space and sign out when exiting.
The attendant shall maintain the permit and sign in log for the duration of the work.

35. JOB FINISHED
Remove all personnel, tools, and debris from the space. Sign off the log.
Close the space.
Cancel the permit.
Review the job with the host employer (hazards, problems, other employers, etc.)

36. ATTENDANT RESPONSIBILITIES
To monitor entrants during the job and during entry & exit to help insure their safety.
The attendant may not abandon his post for any reason while personnel are in the space unless relieved by another qualified attendant.
To monitor atmospheric conditions in the space prior to and during entry.
To control access to the confined space.
To summon emergency assistance as needed.
To assess hazards in and around the space, and take action on the same.
To keep records of confined space work, such as air test results, personnel entry/exit, etc.

37. ENTRANT RESPONSIBILITIES
To assure that the space has been adequately ventilated, isolated, emptied, or otherwise made safe for entry.
To immediately exit a space, without question, upon word of the attendant, no matter what the reason.
To follow all safety rules and procedures that apply to the job.
To be familiar with the work to be performed and the procedures that apply to the job.
To use the appropriate PPE whenever necessary.

38. SUPERVISOR RESPONSIBILITIES
To assure adequate protection is provided to the entrants by verifying adequate lockout/tagout and that all hazards are securely isolated.
To support the attendant’s authority in controlling access to a confined space.
To verify that all personnel have exited prior to closing the space.
To assure that all personnel involved are aware of the hazards associated with the space.
To assure that rescue services are available prior to entry.