Confined Space Entry

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Confined Space Entry
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Objectives

• This is intended an overview of the confined
  space hazards and control
• Students should
• 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

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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.

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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,

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Permit Required Confined Space Definition
(contd)

• 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.

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Confined Space Risk

• Confined spaces are deadly.
• OSHA data (annual)
• 63 fatalities
• 5000 serious injuries
• Up to 60 of victims are would-be rescuers
• 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

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Confined Space Risk

• Utah has many recent fatalities
• 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

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Causes of Death (NIOSH)

• Atmospheric hazards - 56 of fatalities

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Causes of Death (NIOSH)

• Engulfment (34 of fatalities)

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Oxygen-deficient atmospheres

• Oxygen is consumed
• Gases displace oxygen

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Combustible atmospheres

• Flammable gas, vapor or dust
• Oxygen enriched
• Combustible concentrations are far above safe
  toxic exposure

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Toxic atmospheres

• Product stored in the space
• Activity in the confined space
• Sources outside the confined space

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Engulfment

• Bridging
• Slumping
• Hang-up
• Rat hole

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Safety and Physical hazards

• Temperature extremes
• Converging walls or floors
• Mechanical hazards
• Electrical hazards
• Noise?
• Falls - slick/wet surfaces
• Falling objects

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Initial Atmospheric testing

• Oxygen
• Oxygen meters
• Electro-chemical detectors
• Instrument displays Oxygen
• Minimum 19.5 O2 (OSHA limit)
• Test oxygen first

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Initial Atmospheric testing

• Combustible gases and vapors
• Combustible gas meters,
• 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
• No more than LFL (OSHA)
• LFL at approx. 5 foot visibility

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Initial Atmospheric testing

• Toxic gases and vapors
• Toxic gas meters
• Electrochemical detectors
• Detector tubes, etc.
• No more than PEL (TLV, etc.)
• Toxic agent may cause injury or impair escape
  (OSHA)

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Additional atmospheric testing

• After ventilating the space
• Upon first entry
• Continual monitoring if conditions could change
• Personal alarms (for entrants)
• Periodic re-testing

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Instruments for confined spaces

• Combination instruments commonly used
• Multi-gas, LEL, Oxygen
• Instruments must be properly calibrated
• Users must be trained

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Ventilation

• Inerting
• Inert gas displaces oxygen (to control flammable
  hazard)
• IDLH hazard!
• Natural ventilation
• Wind
• Convection

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Ventilation

• Mechanical Ventilation
• Compressed air
• 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

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Ventilation

• Ventilation strategies
• Supply mode
• Exhaust Mode
• Simultaneous supply and exhaust
• Displacement ventilation
• Removes hazard before entry
• Minimum 10 air changes (AC)
• Dilution ventilation reduces hazard during entry

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Ventilation
BAdapted from McManus, Safety and Health in
Confined Spaces,1999
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Isolation

• Tag and lock out circuits and lines
• Disconnect drives and linkages
• Secure moving parts

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Isolation

• Blank and bleed lines
• "Blind" flanges
• "Double Block and Bleed "

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Ignition, electrical

• Ignition control
• Non-sparking tools
• Classified electrical equipment ("Explosion
  proof")
• Electrical control
• Grounding
• Ground Fault Circuit Interrupters
• Isolating transformers

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Personal protective equipment

• Atmosphere supplying respirators

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Personal protective equipment

• Air purifying respirators
• Protective clothing

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Retrieval devices

• Retrieval systems
• Safety belt/harness, lanyards, winch
• Required for top entry (OSHA)
• Prepare for rescue before entry

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Standby/Rescue

• Communications
• Never enter confined spaces alone!
• Outside monitor at all times
• Continuous communication with entrants
• Rescue
• Rescue team on standby
• Monitor summons help
• Never attempt an unplanned confined space rescue!

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Confined Space Programs

• Identify confined space hazards
• Find and evaluate spaces
• Labels, signs

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Confined Space Programs

• Confined Space Entry Permit
• 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

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OSHA, General Industry

• 1910.146, Permit required confined space
• Scope and application(1910.146(a)
• Definitions(1910.146(b)
• Confined Space
• Large enough to enter
• Limited entry or exit
• Not designed for continuous occupancy
• Permit required confined space.-a confined space
  with
• Hazardous atmosphere potential
• Potential for engulfment
• Inwardly converging walls
• Any other recognized safety hazard

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OSHA, General Industry

• General requirements(1910.146(c)
• Evaluate workplace
• Post signs
• Keep employees from entering,
• -or-
• 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

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OSHA, General Industry

• OSHA Permit-required confined space program,
  1910.146(d)
• 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

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OSHA, General Industry

• OSHA Permit-required confined space program,
  1910.146(d), continued
• 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

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OSHA, General Industry

• Permit system, 1910.146(e)
• Procedures before entry
• Permit must be signed
• Permit available to entrants
• Duration specified
• Canceling the entry
• Retained for at least l year

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OSHA, General Industry

• Requirements for the entry permit, 1910.146(f)
• Space
• Purpose
• Date and Duration
• Personnel
• Supervisor
• Hazards
• Control measures
• Acceptable entry conditions
• Test results
• Rescue provisions
• Required equipment
• Other information

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OSHA, General Industry

• Training, 1910.146(g)
• 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)

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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