Download presentation
Presentation is loading. Please wait.
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.
7
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
8
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
9
Causes of Death (NIOSH)
Atmospheric hazards - 56% of fatalities
10
Causes of Death (NIOSH)
Engulfment (34% of fatalities)
11
Oxygen-deficient atmospheres
Oxygen is consumed Gases displace oxygen
12
Combustible atmospheres
Flammable gas, vapor or dust Oxygen enriched Combustible concentrations are far above safe toxic exposure
13
Toxic atmospheres Product stored in the space
Activity in the confined space Sources outside the confined space
14
Engulfment Bridging Slumping Hang-up Rat hole
15
Safety and Physical hazards
Temperature extremes Converging walls or floors Mechanical hazards Electrical hazards Noise? Falls - slick/wet surfaces Falling objects
16
Initial Atmospheric testing
Oxygen Oxygen meters Electro-chemical detectors Instrument displays % Oxygen Minimum 19.5% O2 (OSHA limit) Test oxygen first
17
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
18
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)
19
Additional atmospheric testing
After ventilating the space Upon first entry Continual monitoring if conditions could change Personal alarms (for entrants) Periodic re-testing
20
Instruments for confined spaces
Combination instruments commonly used Multi-gas, LEL, Oxygen Instruments must be properly calibrated Users must be trained
21
Ventilation Inerting Natural ventilation
Inert gas displaces oxygen (to control flammable hazard) IDLH hazard! Natural ventilation Wind Convection
22
Ventilation Mechanical Ventilation Compressed air
May be suitable for small spaces Venturi blowers make more efficient use of compressed air
23
Ventilation Air mover at opening Portable ventilation system
24
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
25
Ventilation Recommended air changes Contaminant reduction Conditions
10 x good mixing and negligible contaminant release 20-30 poor mixing or significant contaminant release poor mixing and significant contaminant release (ventilation alone may not be adequate) Negligible air movement and high contaminant release BAdapted from McManus, Safety and Health in Confined Spaces,1999
26
Isolation Tag and lock out circuits and lines
Disconnect drives and linkages Secure moving parts
27
Isolation Blank and bleed lines "Blind" flanges
"Double Block and Bleed "
28
Ignition, electrical Ignition control Electrical control
Non-sparking tools Classified electrical equipment ("Explosion proof") Electrical control Grounding Ground Fault Circuit Interrupters Isolating transformers
29
Personal protective equipment
Atmosphere supplying respirators
30
Personal protective equipment
Air purifying respirators Protective clothing
31
Retrieval devices Retrieval systems Prepare for rescue before entry
Safety belt/harness, lanyards, winch Required for top entry (OSHA) Prepare for rescue before entry
32
Standby/Rescue Communications Rescue
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!
33
Confined Space Programs
Identify confined space hazards Find and evaluate spaces Labels, signs
34
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
36
OSHA, General Industry 1910.146, Permit required confined space
Scope and application( (a) Definitions( (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
37
OSHA, General Industry General requirements(1910.146(c) -or-
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
38
OSHA, General Industry OSHA Permit-required confined space program, (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
39
OSHA, General Industry OSHA Permit-required confined space program, (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
40
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
41
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
42
OSHA, General Industry Training, 1910.146(g)
Provide all training needed When to provide training Establish employee proficiency Certify training accomplished Duties of entrants, (h) Duties of attendants, (i) Duties of supervisors, (j) Rescue, (k)
43
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.