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Confined Spaces in Construction Awareness Training

Confined Spaces in Construction Awareness Training. Confined Space Fatalities. Introduction. 92 fatalities per year. Objectives. Introduction. Recognize confined spaces and permit-required confined spaces. Identify hazards associated with confined spaces.

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Confined Spaces in Construction Awareness Training

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  1. Confined Spaces in Construction Awareness Training

  2. Confined Space Fatalities Introduction • 92 fatalities per year

  3. Objectives Introduction • Recognize confined spaces and permit-required confined spaces. • Identify hazards associated with confined spaces. • List various methods of controlling hazards. • Recognize signs and symptoms of exposure. • Identify duties of entrants, attendants, and entry supervisors. • Identify emergency procedures.

  4. Causes of Confined Space Deaths Atmospheric Engulfment Some other hazard

  5. Confined Space Characteristics • Large enough to enter • Limited entry and exit openings • Not designed for continuous occupancy

  6. Permit-Required Confined Spaces Any confined space with a serious safety or health hazard

  7. Permit-Required Confined Spaces • A Permit-Required Confined Space (PRCS) will have one or more of the following characteristics: • Contain or has the potential to contain a hazardous atmosphere. • Contain materials that could engulf an entrant. • Have an internal configuration that could trap or asphyxiate an entrant. • Contain any other recognized serious safety or health hazard.

  8. Permit Program Components • Identify confined spaces. • Assess the hazards. • Determine how to manage/control the hazards • Identify permit-required confined spaces. • Produce entry procedures. • Develop entry permit.

  9. The Entry Permit • Permit space • Purpose of entry • Date and duration of permit • Authorized entrants • Attendants • Entry Supervisor • Hazards of the space • Hazard control procedures • Acceptable entry conditions • Atmospheric test results • Emergency procedures • Equipment • Other information

  10. The Entry Permit • Permits must be posted at the • entry of the permit space

  11. Entrant’s Responsibilities • Know all the hazards and signs of exposure. • Properly use all confined space equipment. • Communicate with the Attendant and alert if needed. • Exit from the space if ordered, prohibited conditions exist or any signs/symptoms develop.

  12. Entrant’s Responsibilities You become an Entrant when any part of your body breaks the planeof the permit-required confined space opening.

  13. Attendant’s Responsibilities • Know the hazards of entry and signs of exposure. • Be aware of possible behavior effects. • Maintain accurate accounting of Entrants. • Remain at the entrance to the space. • Communicate with the Entrants and monitor their status.

  14. Attendant’s Responsibilities • Monitors activities inside and outside of space. • Order evacuation of space if needed. • Initiate on-scene rescue procedures. • Keep unauthorized persons away. • Perform no duties that might interfere with primary duties.

  15. Entry Supervisor’s Responsibilities • Know hazards and signs of exposure. • Verifies entries have been made on the permit, all tests have been performed and procedures/equipment are in place. • Terminates entry and cancels permit. • Removes unauthorized individuals. • Ensures acceptable entry conditions exist.

  16. Isolation of Hazards • Double block and bleed • Lockout/tagout • Blanking and bleeding • Disconnecting mechanical linkages • Flushing

  17. Isolation of Hazards DOUBLE BLOCK & BLEED

  18. Isolation of Hazards LOCKOUT/TAGOUT

  19. Isolation of Hazards BLANKING/BLINDING

  20. Atmospheric Hazards Other Gases 1% Oxygen 20.9% Nitrogen 78% Composition of Normal Air

  21. Atmospheric Hazards • Oxygen Deficient: less than 19.5% oxygen • Combustible: LEL over 10% or O2 above 23.5% • Toxic: Toxic gases, vapors, mists, or dusts at or above PEL It is possible to have any combination of these three hazards.

  22. Atmospheric Hazards Human senses (sight, smell, taste) cannot protect you from hazardous atmospheres since: __________________________ some gases have no taste or odor.

  23. Floats Drifts Sinks Atmospheric Hazards • Stratification • Pocketing • Floating

  24. Atmospheric Hazards Hydrogen: 0.07 Methane: 0.55 Carbon Monoxide: 0.96 Nitrogen: 0.97 Air: 1.0 Hydrogen Sulfide: 1.19 Argon: 1.38 Carbon Dioxide: 1.52 Gasoline: 3.0-4.0 Lighter than Air Heavier than Air

  25. Atmospheric Hazards Causes of Oxygen Deficiency • Displacement • Bacteria (rot) • Oxidation (rust) • Combustion • Absorption • Breathing

  26. Atmospheric Hazards Symptoms Oxygen Level Minimum permissible level Possibly impaired coordination Respiratory/pulse increase, impaired judgment/coordination Further increase in respiration, pulse Fainting, nausea, vomiting, blue lips 4 – 5 minutes: Recovery with treatment 6 minutes: 50% mortality 8 minutes: 100% mortality Coma in 40 seconds or less 19.5% 15 – 19% 12 – 14% 10 – 12% 8 – 10% 6 – 8% 0 – 6%

  27. Oxygen Fuel Ignition Atmospheric Hazards • Sufficient oxygen • Sufficient fuel • Ignition source (flame, spark, hot surface)

  28. Atmospheric Hazards Flammable Particulates in the Atmosphere • If vision is obscured by flammable dusts or mists at a distance of five feet, a hazard exists.

  29. Atmospheric Hazards Flammability Limits LEL – Lower Explosive Limit • Lowest mixture of gas/vapor and air that will ignite; a mixture below LEL is too lean to burn. UEL – Upper Explosive Limit • Highest mixture of gas/vapor and air that will ignite; a mixture above UEL is too rich to burn.

  30. Below LEL Above UEL Combustible 0% 25% 50% 75% 100% Atmospheric Hazards Propane Hexane Hydrogen Acetylene Percent of Gas by Volume

  31. Atmospheric Hazards Sources of Toxic Atmospheres • Bacteria • Toxins stored (or once stored) in the space • Substances brought into the space • Work being conducted in or near the space • Engine exhaust

  32. Atmospheric Hazards Methane (CH4) • One of the most common flammable gases • Colorless and lighter than air • Can cause asphyxiation • LEL = 5% by volume

  33. Atmospheric Hazards Carbon Dioxide (CO2) • Odorless • Colorless • Component of normal air • Heavier than air • Byproduct of fermentation and organic decay

  34. Atmospheric Hazards Carbon Dioxide Symptoms • Headaches and dizziness • Prickling or burning skin sensations • Breathing difficulty or painful breathing • Sweating and a sense of malaise

  35. Atmospheric Hazards Carbon Monoxide (CO) • Product of incomplete combustion • Odorless and colorless • Interferes with the blood’s ability to transport oxygen

  36. Atmospheric Hazards Symptoms Exposure Time CO Level Permissible Exposure Level Slight headache, other discomfort Headache, discomfort, irritation Confusion, headache, nausea, tendency to stagger, slight heart palpitations Unconsciousness 35 200 400 – 600 1000 – 2000 2000 - 5000 8 hours 3 hours 1 – 2 hours ½ - 2 hours Minutes

  37. Atmospheric Hazards Hydrogen Sulfide (H2S) • Irritant of the mucous membranes • Toxic (PEL = 10 PPM) • Flammable (LEL = 4% by volume) • Heavier than air • Rotten egg odor • Diminishes a person’s ability to smell (olfactory fatigue)

  38. Atmospheric Hazards Hydrogen Sulfide Exposure Symptoms H2S Level Exposure Time 10 50 – 100 200 – 300 500 – 700 1000 Permissible Exposure Level Mild eye and respiratory irritation Marked eye and respiratory irritation Unconsciousness, death Unconsciousness, death 8 hours 1 hour 1 hour ½ - 1 hour Minutes

  39. Atmospheric Monitors The atmosphere in the space must be tested to ensure that no hazards exist. An inaccurate monitor will not protect you. You should always calibrate and zero the monitor. You should also ensure that the alarms are working, and that you will be able to see and hear them.

  40. Atmospheric Monitors Monitors measure the percent of LEL, not the percent of gas vapors. In a confined space, an atmosphere with 10% LEL can be at 100% just a few feet away. Continuous monitoring is REQUIRED for Permit-Required Confined Spaces.

  41. Assessing Air Quality • Test for oxygen first • Test for combustibles • Test for toxins • Be sure to test ALL levels

  42. Communications • Attendant and Entrant must remain in constant communication. • Can use voice, radios, hard-wired systems, hand or rope signals. • Attendant must be able to contact the rescue team.

  43. Access, Fall Protection, and/or Retrieval Body Support Hoisting Component Anchorage Component

  44. 29 CFR 1926.1211(c)(2) A mechanical device shall be available to retrieve personnel from vertical type permit-spaces more than 5 feet deep.

  45. Space Ventilation • Maintain acceptable atmosphere • Hang hose at least 2 feet above the floor • Ensure blower supplies clean air

  46. Space Ventilation WIND WIND NEGATIVE PRESSURE POSITIVE PRESSURE One opening Dilution method One opening Source capture

  47. Space Ventilation WIND WIND RECIRCULATING SHORT CIRCUTING Hose too short. Air turns to path of least resistance. Fan intake downwind. Hazardous air is drawn into fan.

  48. Space Ventilation 15’ 10’ 20’

  49. Space Ventilation Estimating Approximate Purge Times 1,000-10,000 Cubic Space Capacity

  50. In an Emergency • Evacuate the space. • Contact the rescue team. • Attempt non-entry rescue. • Gather information.

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