Confined Space Entry
Confined Space
(1) Large enough for an employee to
bodily enter and perform work AND
(2) Has limited or restricted entry or exit
AND
(3) Is not designed for continuous
employee occupancy
Permit Required Confined Space
A confined space that:
(1) contains or has a potential to contain a
hazardous atmosphere OR
(2) has the potential for engulfment OR
(3) Has an internal configuration that could trap
or asphyxiate OR
(4) Contains any other recognized serious safety
or health hazard
Confined Space Question…
• Why are we entering this space?
Limited Or Restricted Entry
• Any space where an occupant
o
o
o
o
o
Must crawl, climb, twist
Be constrained in a narrow opening
Follow a lengthy path
Exert unusual effort to enter or leave
May become trapped
 Entrance may become sealed or secured
against opening from inside
Confined Spaces
Hazardous Atmosphere
• Potential exposure to
o Risk of death
o Incapacitation
o Impairment of ability to self-rescue
o Injury
o Acute illness
• If none of the above
o Does not apply to this standard
Reclassify
• Reclassify to a non-permit space if
All potential for a hazardous atmosphere is
eliminated AND
o All other hazards and potential hazards are
eliminated/controlled
o
Air & Oxygen
• Air and oxygen are NOT synonymous.
• Air contains
o
o
o
o
20.9% oxygen
78.1% nitrogen
1% argon
Trace amounts of other gases
Hazardous Atmosphere
• Flammable gas, vapor, or mist in excess of 10
percent of its lower flammable limit (LFL)
• Airborne combustible dust at a concentration
that meets or exceeds its LFL
o
Or visibility 5’ or less
Hazardous Atmosphere
• Atmospheric oxygen concentration below 19.5
percent or above 23.5 percent
• Atmospheric concentration of any toxic
substance for which a dose or a permissible
exposure limit is published
• Any other atmospheric condition that is
IMMEDIATELY DANGEROUS TO LIFE OR
HEALTH. (IDLH)
Delayed Threat
• Cadmium vapor and hydrogen fluoride
o May seem ok; immediate symptoms
go away
o Fatal 12 to 72 hours later
Conditions That Can Cause Oxygen
Deficiency
• Adsorption by porous surfaces
o Activated charcoal
• Consumed by chemical reactions
o Rusting
o Fermentation
• Displaced
o Inert gasses
 Argon
 CO2
 Nitrogen
Conditions That Can Cause
Oxygen Enrichment
• Poorly designed or malfunctioning O2
storage or dispensing equipment
• Leaks from oxy-acetylene welding or
cutting equipment
o
Couplings, fittings hoses
• Ventilating with pure oxygen
Flammable Atmospheres
• Vapor burns, not liquid
• Flammability based on
o
o
Amount of vapor
Temperature
Tank Residue
• Explosions often caused by residue in
“empty” tanks or spaces
Residue In Tanks 99% Empty
TANK SIZE (GALLONS)
50,000
40,000
30,000
20,000
10,000
5,000
2,500
1,000
RESIDUE (GALLONS)
500
400
300
200
100
50
25
10
Upper & Lower Flammable Limits
AIR
100%
EXPLOSIVE
RANGE
LEAN
0%
0%
RICH
100%
GAS
LEL
UEL
Flammable Atmosphere: Propane
Flammable Atmospheres
Ignition Sources
• Open flame
• Electrical arcing
• Hot surfaces
o
Light bulbs
• Static electricity
• Frictional sparks
• Chemical reactions
230o C
Control Of Ignition Sources
•
•
•
•
•
•
Non-sparking tools
Approved electrical equipment
Purged & pressurized equipment
Intrinsically safe equipment
Explosion proof equipment
Vessel inerting
Control Of Ignition Sources: Hot Work
Precautions
• Hot work permits
• Welding & cutting precautions
o
o
Control of torches & control valves
Hoses & regulators
 In good condition
 Inspected
 Minimal tape
o
Fire prevention & protection
Toxic Atmospheres
TOXIC:
• Harmful, destructive
• Deadly
• Poisonous
(THE AMERICAN HERITAGE DICTIONARY)
Sources of Toxic Atmospheres
• Products stored in space
• Work being performed in space
o
o
Painting, cleaning & degreasing
Welding, cutting & brazing
• Adjacent areas
o Toxins enter & accumulate
o Leaching
o Chemicals dumped into sewers,
streams
Toxic Gasses
• Irritant Gas
o
o
Serious effects may be delayed
Examples
 Ammonia, chlorine, sulfur dioxide, ozone,
nitrogen dioxide
• Asphyxiate Gas
o
o
Smothers due to lack of oxygen
Two classes
 Simple asphyxiates
 Chemical asphyxiates
Simple Asphyxiates
Displaces oxygen:
• Acetylene
• Argon
• Ethane
• Ethylene
• Helium
•
•
•
•
•
Hydrogen
LP gas
Methane
Neon
Nitrogen
Chemical Asphyxiates
Cause asphyxiation through biochemical
reaction
• Hydrogen sulfide
• Carbon monoxide
• Hydrogen cyanide
Engulfment
"The surrounding and effective capture of
a person" by
• A liquid
OR
• Finely divided (flowable) solid
Engulfment
• Quicksand effect
• Material drawn from bottom
• Bridges created by air pockets
Air Pocket
Mechanical Hazards
• Manually isolate each piece of
equipment
o
Prevent vapor leaks, flashbacks, etc.
• All pipes must be physically
disconnected or isolation blanks bolted
in place
o
o
Closing valves not sufficient
Inspect & test for leakage
• Also consider steam valves, pressure
lines, chemical transfer pipes
Lockout - Tagout
• Render ALL hazardous equipment
related to space inoperable
o
Including accidental startup by others
Refer to Lockout/Tagout Standard: 1910.147
Control, Isolation Methods
•
•
•
•
•
•
Lockout/tagout
Purging
Block & bleed
Inerting
Ventilating
Flushing
Noise
• Noise usually intensified in spaces
o
Exposure may be higher than in open
environment
• May disrupt verbal communication
o
Especially with attendant
Air Testing Instruments
• Many different kinds of instruments
• Results not instantaneous
o
Delay for portable instruments 30-60
seconds
• Assure properly calibrated
• Proper care & maintenance
o
Per manufacturer
Air Testing Instruments
• Understand use & limitations
Accuracy may be +/- 2%, 5%…
May be affected by extremes of
temperature
o May be affected by rich CO2 atmosphere
o May only operate properly within certain
temperatures and relative humidity
o
o
Air Testing
• Test in order
o
o
o
•
•
•
•
Oxygen
Flammables
Toxins
Test at various levels
Test various places
Continuously monitor
Test around cover before opening
Air
Testing
Alarm Devices
• ”Alarm only" devices which do not
provide readings are not acceptable
o
o
For initial (pre-entry) or
Periodic (assurance) testing
• Not enough information to establish
acceptable entry conditions
• Combination units may be acceptable
o
Benefit of automatic alarming at
predetermined value.
Ventilation Equipment
• Wide variety of types of ventilation
equipment
o
o
o
Size & portability
Air volume capabilities
Power sources
Ventilation Only Entry
Required
• Demonstrate: only hazard is actual or
potential hazardous atmosphere
• Demonstrate: continuous forced air
ventilation alone is sufficient to maintain
safe entry
• Develop monitoring and inspection data
to support these demonstrations
Hazard Control Hierarchy
• Eliminate hazard
o
o
Engineering controls
Process modification
• Substitute less hazardous
o
o
o
Materials
Methods
Techniques
• Personal protective equipment
Personal Protective Equipment
•
•
•
•
•
Proper fit
Cleaning & maintenance
Replacement
Proper use
Will not interfere with movement within
space
• Employee training
Respiratory Protection
• Vast selection
o
o
o
Types, styles
Limitations
Specific uses
• Have selection made by qualified
person
Permit-required Spaces
General Requirements
• Evaluate:
• Identify all confined spaces
• Evaluate to determine if any spaces are
permit required confined spaces.
Permit-required Spaces
General Requirements
• Notify employees of
o
o
o
Existence
Location and
Danger
• Post signs
There, and
there, and over
there...
Permit-required Spaces
General Requirements
• If employees will enter permit spaces:
o
Develop & implement a written permit
space program
Written Program
• Ensure that EVERY confined space is
o
o
Evaluated as a possible permit space
Reevaluated when its uses or surroundings
change.
Entry
“IS CONSIDERED TO HAVE
OCCURRED AS SOON AS ANY PART
OF THE ENTRANT'S BODY BREAKS
THE PLANE OF AN OPENING INTO THE
SPACE”
Permit Required Confined Space
Entry Team
•
•
•
•
Entrant
Attendant
Entry supervisor
Rescuers
Rescuers
• 60% OF CONFINED SPACE VICTIMS
ARE WOULD BE RESCUERS (NIOSH
STUDY)
Dial 911 - ?
•
•
•
•
Must be informed of hazards
Must have access to all permit spaces
Must be trained
Should be available
o
Make arrangements BEFORE need arises
Non-entry Rescue
• Use non-entry rescue whenever
possible
• Use retrieval systems or methods
whenever an entrant enters a permit
space
o
Unless the retrieval equipment would
increase the overall risk of entry or would
not contribute to the rescue of the entrant
Non-entry Rescue
• A mechanical device
must be available for
rescue for vertical
type permit spaces
more than 5 feet
deep.
Entry Permit
• Actual document
• Contains specific required information
about entry
• Provides history of entry
Enter
• Retain for at least 1 year
space
#12
QUESTIONS
????
SANDRA A. MIHALIK
Safety & Health Specialist
Montana Safety & Health
Bureau
406.444.6418
e-mail: smihalik@mt.gov