Transcript Confined Space Entry Objectives This is intended an overview of the confined space hazards and control Students should:      Understand the extent of the problem Know.

Confined Space Entry
Objectives
This is intended an overview of the confined
space hazards and control
Students should:
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Understand the extent of the problem
Know applicable definitions
Recognize the hazards of confined spaces
Be familiar with methods to control these hazards
Know basic OSHA requirements for confined
space entry
Confined Space: Definition
A Confined Space means a space that:
Is large enough and so configured that an
employee can bodily enter and perform
assigned work ; and
Has a limited or restricted means for entry or
exit (For example: tanks, vessels, silos, pits,
vaults,hoppers);and,
Is not designed for continuous employee
occupancy.
Permit Required
Confined Space: Definition
A Permit Required Confined Space means a
confined space that has one or more of the
following characteristics:
Contains or has a potential to contain a
hazardous atmosphere,
Contains a material that has the potential for
engulfing an entrant,
Permit Required Confined
Space: Definition (cont’d)
A Permit Required Confined Space means a
confined space that has one or more of the
following characteristics:
Has an internal configuration such that an
entrant could be trapped or asphyxiated by
inwardly converging walls or by a floor which
slopes downward and tapers to a smaller
cross-section.
Contains any other serious safety or health
hazard.
Confined Space Risk
Confined spaces are deadly.
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OSHA data (annual)
 63 fatalities
 5000 serious injuries
 Up to 60% of victims are would-be rescuers
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NIOSH documents:
Preventing Occupational Fatalities in Confined Spaces
Preventing Entrapment and Suffocation Caused by the
Unstable Surfaces of Stored Grain and Other Materials
(1987)
Preventing Deaths of Farm Workers in Manure Pits
Preventing Occupational Fatalities in Confined Spaces
Confined Space Risk
Utah has many recent fatalities:
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Two welders died inside a pipe from argon
asphyxiation, 1997
An employee died after being buried with salt
while cleaning a bin, 1995
Two maintenance workers (one was a "rescuer")
died from nitrogen asphyxiation while working in
an oil-refinery tank, 1995
Two relatives (uncle and nephew) died inside an
asphalt truck tank, 2000
A central Utah dairy worker was asphyxiated when
he fell into a manure pit, 1998
A truck driver died when he went into a storage
tank
Causes of Death (NIOSH)
Atmospheric hazards - 56% of
fatalities
Causes of Death (NIOSH)
Engulfment (34% of fatalities)
Oxygen-deficient atmospheres
Oxygen is consumed
Gases displace
oxygen
Combustible atmospheres
Flammable gas,
vapor or dust
Oxygen enriched
Combustible
concentrations
are far above
safe toxic
exposure
Toxic atmospheres
Product stored
in the space
Activity in the
confined
space
Sources
outside the
confined
space
Engulfment
Bridging
Slumping
Hang-up
Rat hole
Safety and Physical hazards
Temperature extremes
Converging walls or floors
Mechanical hazards
Electrical hazards
Noise?
Falls - slick/wet surfaces
Falling objects
Initial Atmospheric testing
Oxygen
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Oxygen meters
 Electro-chemical detectors
 Instrument displays %
Oxygen
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Minimum 19.5% O2
(OSHA limit)
Test oxygen first
Initial Atmospheric testing
Combustible gases and vapors
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Combustible gas meters,
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“Heat of combustion" meters
Combustible gas meters need oxygen to work
Instrument displays Percent Lower Explosive Limit (LEL)
(OSHA uses the term Lower Flammable, LFL)
No more than 10% LFL (OSHA)
Combustible dusts
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No more than LFL (OSHA)
LFL at approx. 5 foot visibility
Initial Atmospheric testing
Toxic gases and vapors
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Toxic gas meters
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Electrochemical detectors
Detector tubes, etc.
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No more than PEL (TLV, etc.)
Toxic agent may cause injury or impair
escape (OSHA)
Additional atmospheric testing
After ventilating the space
Upon first entry
Continual monitoring if conditions could
change
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Personal alarms (for entrants)
Periodic re-testing
Instruments for confined
spaces
Combination
instruments commonly
used
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Multi-gas, LEL, Oxygen
Instruments must be
properly calibrated
Users must be trained
Ventilation
Inerting
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Inert gas displaces oxygen (to control flammable
hazard)
IDLH hazard!
Natural ventilation
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Wind
Convection
Ventilation
Mechanical Ventilation
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Compressed air
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May be suitable for small spaces
Venturi blowers make more efficient use of compressed air
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Ventilation
Air mover at
opening
Portable
ventilation
system
Ventilation
Ventilation strategies
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Supply mode
Exhaust Mode
Simultaneous supply and exhaust
Displacement ventilation
 Removes hazard before entry
 Minimum 10 air changes (AC)
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Dilution ventilation reduces hazard during entry
Ventilation
Recommended
air changes
Contaminant Conditions
reduction
10
10 - 100x
20-30
10 - 100x
30 - 60
10 - 100x
60 - 100
(ventilation
alone may not
be adequate)
good mixing and negligible
contaminant release
poor mixing or significant
contaminant release
poor mixing and significant
contaminant release
Negligible air movement and
high contaminant release
BAdapted from McManus, Safety and Health in Confined Spaces,1999
Isolation
Tag and lock out
circuits and lines
Disconnect drives
and linkages
Secure moving
parts
Isolation
Blank and bleed
lines
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"Blind" flanges
"Double Block and
Bleed "
Ignition, electrical
Ignition control
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Non-sparking tools
Classified electrical equipment ("Explosion proof")
Electrical control
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Grounding
Ground Fault Circuit Interrupters
Isolating transformers
Personal protective equipment
Atmosphere
supplying
respirators
Personal protective equipment
Air purifying
respirators
Protective
clothing
Retrieval devices
Retrieval systems
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Safety belt/harness, lanyards,
winch
Required for top entry (OSHA)
Prepare for rescue before
entry
Standby/Rescue
Communications
Never enter confined spaces alone!
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Outside monitor at all times
Continuous communication with entrants
Rescue
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Rescue team on standby
Monitor summons help
Never attempt an unplanned confined space
rescue!
Confined Space Programs
Identify
confined
space hazards
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Find and
evaluate spaces
Labels, signs
Confined Space Programs
Confined Space Entry Permit
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Test space before entry
Specify precautions and conditions and duration of
permit
Sign permit and post on site
Permit cancelled at end of job or if conditions
change
OSHA, General Industry
1910.146, Permit required confined space
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Scope and application(1910.146(a)
Definitions(1910.146(b)
 Confined Space:
 Large enough to enter
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Limited entry or exit
Not designed for continuous occupancy
 Permit required confined space.-a confined space with:
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Hazardous atmosphere potential
Potential for engulfment
Inwardly converging walls
Any other recognized safety hazard
OSHA, General Industry
General requirements(1910.146(c)
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Evaluate workplace
Post signs
Keep employees from entering,
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Establish entry program
Alternate procedures for spaces where ventilation alone is
adequate to control hazard
Re-evaluate as necessary
Re-classify spaces as necessary
Employer coordinates with contractors
Contractors coordinate with employer
OSHA, General Industry
OSHA Permit-required confined space
program, 1910.146(d)
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Prevent unauthorized entry
Identify and evaluate before entry
Develop means and procedures for safe entry
Provide equipment, training
Evaluate permit space conditions
 Employee observation
 Inform employees of result
OSHA, General Industry
OSHA Permit-required confined space
program, 1910.146(d), continued
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Provide outside attendant
Provisions for multiple spaces (single attendant)
Designate persons and roles
Rescue and emergency procedures
System for entry permits
Procedures for contractors
Procedures to conclude the entry
Review to correct deficiencies
Review and revise the program
OSHA, General Industry
Permit system, 1910.146(e)
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Procedures before entry
Permit must be signed
Permit available to entrants
Duration specified
Canceling the entry
Retained for at least l year
OSHA, General Industry
Requirements for the entry permit,
1910.146(f)
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Space
Purpose
Date and Duration
Personnel
Supervisor
Hazards
Control measures
Acceptable entry conditions
Test results
Rescue provisions
Required equipment
Other information
OSHA, General Industry
Training, 1910.146(g)
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Provide all training needed
When to provide training
Establish employee proficiency
Certify training accomplished
Duties of entrants, 1910.146(h)
Duties of attendants, 1910.146(i)
Duties of supervisors, 1910.146(j)
Rescue, 1910.146(k)
OSHA, General Industry
Appendix A - Flow Chart
Appendix B - Procedures for
Atmospheric testing
Appendix C - Examples of Confined
Space Programs
Appendix D - Sample Permits
Appendix E - Sewer System Entry