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Confined Space Entry

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Confined
Space
Hazards
We Will Discuss:
Confined Space vs Permit Required Confined Space
Types of confined spaces
Confined space hazards
Physical reactions to atmospheric hazards
Methods of eliminating or controlling hazards
WHAT IS A CONFINED SPACE
* Space large enough to enter &;
* Limited or Restricted entry or exit &;
* Not designed for continuous worker
occupancy.
YES
NO
Not a confined Space
Confined Space
Let’s take a look at some typical
confined spaces
Typical Confined Spaces
Utility Vault
Culvert
Trenches
Manhole
Pit
Pipes
Furnaces
Boilers
Tunnels
Pumping Station
Septic Tank
Silo
Storage Tank
Barges
Sewer
Ducts
What Is...
Limited Openings for Entry/Exit
Openings as small as 18 inches in diameter.
Difficult to enter with SCBA or other lifesaving equipment.
Difficult to remove downed worker in folded
up or bent over position.
Exit from large openings may be difficult due
to presence of ladders, hoists, etc.
What Is...
Unfavorable Natural Ventilation
Lack of air movement in and out of the
space can create an atmosphere much
different than the outside atmosphere.
Deadly gases can be trapped inside.
Organic materials can decompose.
May not be enough oxygen due to
presence of other gases or chemical
reactions such as rusting.
What Is...
Not Designed for Continuous Worker
Occupancy
Most confined spaces are not designed to enter and
work in on a regular basis.
Designed to store a product.
Enclose materials or processes.
Transport products or substances.
Occasional worker entry for inspection, repair,
cleanup, maintenance, etc.
Let’s take a look at Permit Required Confined Spaces
WHAT IS A PERMIT CONFINED SPACE
A Permit Confined Space meets the confined space definition
* Space large enough to enter &;
* Limited or Restricted entry or exit &;
* Not designed for continuous worker
occupancy.
YES
NO
Not a confined Space
Confined Space In addition, it contains one
or more of the following
PermitRequired
Confined
Space
Hazardous Atmosphere
YES
Or
Engulfment Hazard
Or
Configuration Hazard
Or
Any other recognized
serious hazard
Non
NO
Permit
Required
Space
General Safety Hazards
Mechanical hazards
-
Mixers
Crushers
Communication
problems
Entry and exit
Physical
пЃ¬
пЃ¬
пЃ¬
Thermal effects
Noise
Vibration
General / physical
пЃ¬
пЃ¬
Surface residues
Structural hazards
Fall hazards
Engulfment hazards
Atmospheric Hazards
Oxygen Deficient Atmospheres
пЃ¬
Less than 19.5% by volume
Oxygen Enriched Atmospheres
пЃ¬
Greater than 23.5% by volume
Flammable Atmospheres
Toxic Atmospheres
Asphyxiation
Is the Leading Cause
of Death in Confined
Spaces.
Oxygen Deficiency Can Be
Caused by CONSUMPTION.
“Hot work” (welding)
Breathing
Chemical reactions (ex. Oxidation of
chemicals or metal)
Biological action (ex. Decomposing organic
matter)
Oxygen Deficiency Can Be
Caused by DISPLACEMENT.
Argon
Nitrogen
Helium
Carbon monoxide, carbon dioxide
Cleaning agents, adhesives, or other
chemicals
Oxygen Deficient
Atmospheres
19.5 %
15 - 19%
12-14%
10-12%
8-10%
6-8%
4-6%
Minimum acceptable oxygen level
Decreased ability to work strenuously,
Impaired coordination
Respiration increases, Impaired judgment
Resp. increases, poor judgment, lips blue
Mental failure, fainting, unconsciousness,
nausea and vomiting
8 minutes – 100% fatal / 6 minutes - 50%
fatal / 4-5 minutes - possible recovery
Coma in 45 seconds, death
Oxygen Enriched
Atmospheres
Oxygen level above 23.5%.
Causes flammable and combustible materials
to burn violently when ignited.
пЃ¬
пЃ¬
Hair, clothing, materials, etc.
Oil soaked clothing and materials.
Never use pure oxygen to ventilate.
Never store or place compressed tanks in a
confined space.
Toxic Atmospheres
Product stored in a confined space:
пЃ¬
пЃ¬
пЃ¬
Gases released when cleaning.
Materials absorbed into walls of confined space.
Decomposition of materials in the confined space.
Work performed in a confined space:
пЃ¬
пЃ¬
пЃ¬
Welding, cutting, brazing, soldering.
Painting, scraping, sanding, degreasing.
Sealing, bonding, melting.
Areas adjacent to a confined space.
Carbon Monoxide
Odorless, colorless chemical asphxiant / flammable gas
/ by-product of combustion / quickly collapse at high
concentrations
PPM
35
Effect
Permissible Exposure Level
Time
8 hours
200
Slight headache, discomfort
2-3 hours
400
Headache and nausea
1-2 hours
800
Headache, dizziness, nausea
45 min.
1,600
Headache, dizziness, nausea
20 min.
3,200
Headache and dizziness
5-10 min.
6,400
Headache and dizziness
1-2 min.
Hydrogen Sulfide
Very strong asphyxiant with rotten egg odor / flammable gas
/ by-product of the decomposition of organic matter / 4 times
heavier than air / possibly no warning at high concentrations
PPM
10
Effect
Permissible Exposure Level
Time
8 hours
50 - 100
Mild Irritation - eyes, throat
1 hour
100
Desensitizes olfactory nerve
2-5 min.
250 - 350
Unconsciousness, death
4-8 hrs.
500 -600
Unconsciousness, death
30-60 min.
>1000
Unconsciousness, death
minutes
Flammable Atmospheres
Critical Factors:
пЃ¬
пЃ¬
пЃ¬
Oxygen content in the air.
Flammable gases or vapors
Flammable dust (visibility of 5’ or less)
Proper air/gas mixture can lead to explosion
Typical Ignition Sources:
пЃ¬
пЃ¬
пЃ¬
Sparking or electric tool.
Welding / cutting operations.
Smoking
Lower Explosive Limit vs.
Upper Explosive Limit
AIR
COMBUSTIBLE
TOO LEAN TO BURN
LEL
Gasoline
0%
EXPLOSIVE
RANGE
TOO RICH TO BURN
UEL
1.4% пѓџFlammable rangeпѓ 7.6% by volume
100%
Temperature Extremes
Extremely hot or cold temperatures.
Steam cleaning of confined spaces.
Humidity factors.
Extremely cold liquids.
Work processes inside the confined
space can increase temperature
extremes.
Personal protective equipment.
Engulfment Hazards
Loose, granular materials stored in bins
and hoppers - grain, sand, coal, etc.
Crusting and bridging below a worker.
Flooding of confined space.
Water or sewage flow.
Other Hazards
Noise
Amplified due to acoustics within the space.
пЃ¬ Damaged hearing, affect communication.
пЃ¬
Slick / Wet Surfaces
Slips and falls.
пЃ¬ Increased chance of electric shock.
пЃ¬
Falling Objects
пЃ¬
Topside openings expose workers inside
confined space to falling objects.
Testing The Atmosphere
Verify presence of safe work atmosphere.
Test all areas of a confined space.
пЃ¬ Top, Middle, Bottom
Methane is lighter than air.
Carbon Monoxide is the same as air.
Hydrogen Sulfide is heavier than air.
Oxygen Deficiency.
Testing, Evaluation and
Monitoring
Test the atmosphere before entry!
Test in the following order
пЂ­ Oxygen
пЂ­ Combustibles
пЂ­ Toxics
Test for stratified atmospheres as illustrated on next
slide
Evaluate:
пЃ¬ methods for isolating the space
пЃ¬ safe entry procedures
пЃ¬ special tools needed
пЃ¬ communication equipment needed
Monitor the atmosphere continuously to determine
any changes
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
IDLH
Immediately Dangerous to Life or Health
Any condition which poses an immediate
threat to the health of life on an entrant, or;
Would cause irreversible adverse health
effects, or;
Would interfere with an individual’s ability
to escape unaided from a permit space.
All Confined Spaces should be considered
IDLH until proven otherwise!
Acceptable Atmospheric
Conditions
Oxygen concentration
19.5% to 23.5%
Flammable gas, vapor,
or mist
below 10% of the
products LEL
Toxic gas, vapor, or
mist
below the PEL of the
product
Common Factors in
Confined Space Fatalities
Failure to recognize a confined space
Failure to recognize the hazards involved in
confined space entry
Tendency to trust physical senses
Tendency to under-estimate the danger.
Complacent attitude
Attempt to save a co-worker
Approximately 60% of
All Confined Space
Fatalities Occur
Among
Would Be Rescuers!!
Ventilation
First option to correct problems.
Must be aware of hazards you are trying
to correct in the confined space.
Air intake in a safe location to draw
fresh air only.
Continuous ventilation whenever
possible.
Retest the confined space before entry.
Isolation
Locking and tagging out electrical sources.
Blanking and bleeding pneumatic and
hydraulic lines.
Disconnecting mechanical drives and shafts.
Securing mechanical parts.
Blanking sewer and water flow.
Locking and tagging out shutoff valves.
Non-Permit Confined
Space Entry
Isolate the space
Ventilate the space
Evaluate the space
Test atmosphere
пЃ¬ Assure justification conditions are met
пЃ¬ Document, Document, Document
пЃ¬
Enter the space
Isolate the Space from all Hazards
Close Valves
пЃ¬
пЃ¬
Double block & bleed, or
Blank flange
Empty the Space
пЃ¬
Depressurize, vent & drain
Lockout/Tagout Equipment
пЃ¬
пЃ¬
пЃ¬
Electrical sources
Rotating/reciprocating parts
Hazardous materials
Clean residue from the space
Ventilate the Space
Use mechanical ventilation
пЃ¬ Fans
пЃ¬ Air horns
Ventilate at the rate of at least four (4)
volumes per hour
пЃ¬ Larger spaces require more ventilation
Make sure air supply is not contaminated
пЃ¬ Ventilation air supply must be from fresh
air uncontaminated with flammables,
toxins, etc.
Evaluate the Space
Determine that the space meets all the conditions set forth in
the non-permit justifications
Conduct atmospheric testing
Evaluation must be certified by Entry Supervisor’s signature
Determine that the confined space does not:
пЃ¬ contain or have the potential to contain a hazardous
atmosphere
пЃ¬ Continuous mechanical ventilation not acceptable as
good atmosphere
пЃ¬ contain a material with the potential for engulfment
пЃ¬ Has an internal configuration which could trap or
asphyxiate, or
пЃ¬ contain any recognized serious safety or health hazard
Enter the Space and Proceed
with work:
If non-permit conditions change during the
job, the space shall be immediately
evacuated, and re-classified as a permitrequired confined space; or conditions shall
be returned to non-permit conditions and
again certified as such by the entry
supervisor.
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.
QUESTIONS? See your supervisor
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