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Confined Space Entry

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 applicable definitions Recognize the hazards of confined spaces Be familiar with methods to control these hazards

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Confined Space Entry

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  1. Confined Space Entry

  2. 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

  3. 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.

  4. 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,

  5. 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.

  6. 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

  7. 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

  8. Causes of Death (NIOSH) • Atmospheric hazards - 56% of fatalities

  9. Causes of Death (NIOSH) • Engulfment (34% of fatalities)

  10. Oxygen-deficient atmospheres • Oxygen is consumed • Gases displace oxygen

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

  12. Toxic atmospheres • Product stored in the space • Activity in the confined space • Sources outside the confined space

  13. Engulfment • Bridging • Slumping • Hang-up • Rat hole

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

  15. Initial Atmospheric testing • Oxygen • Oxygen meters • Electro-chemical detectors • Instrument displays % Oxygen • Minimum 19.5% O2 (OSHA limit) • Test oxygen first

  16. 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

  17. 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)

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

  19. Instruments for confined spaces • Combination instruments commonly used • Multi-gas, LEL, Oxygen • Instruments must be properly calibrated • Users must be trained

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

  21. Ventilation • Mechanical Ventilation • Compressed air • May be suitable for small spaces • Venturi blowers make more efficient use of compressed air

  22. Ventilation • Air mover at opening • Portable ventilation system

  23. 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

  24. Recommended air changes Contaminant reduction Conditions 10 10 - 100x good mixing and negligible contaminant release 20-30 10 - 100x poor mixing or significant contaminant release 30 - 60 10 - 100x poor mixing and significant contaminant release 60 - 100  (ventilation alone may not be adequate) Negligible air movement and high contaminant release Ventilation BAdapted from McManus, Safety and Health in Confined Spaces,1999

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

  26. Isolation • Blank and bleed lines • "Blind" flanges • "Double Block and Bleed "

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

  28. Personal protective equipment • Atmosphere supplying respirators

  29. Personal protective equipment • Air purifying respirators • Protective clothing

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

  31. 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!

  32. Confined Space Programs • Identify confined space hazards • Find and evaluate spaces • Labels, signs

  33. 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

  34. 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

  35. 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

  36. 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

  37. 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

  38. 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

  39. 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

  40. 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)

  41. 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

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