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 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 ; andHas 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. 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 Unst

able Surfaces of Stored Grain and Other Materials (1987)  Preventing Deaths of Farm Workers in Manure Pits  Preventing Occupational Fatalities in Confined Spaces

Confined Space RiskUtah 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

Causes of Death (NIOSH)

Atmospheric hazards - 56% of fatalities

Engulfment (34% of fatalities)

Causes of Death (NIOSH)

Oxygen-deficient atmospheres

Oxygen is consumedGases displace oxygen

Combustible atmospheres

Flammable gas, vapor or dustOxygen enriched Combustible concentrations are far above safe toxic exposure

Toxic atmospheres

Product stored in the spaceActivity in the confined spaceSources outside the confined space

Engulfment

BridgingSlumpingHang-upRat hole

Safety and Physical hazards

Temperature extremesConverging walls or floorsMechanical hazardsElectrical hazardsNoise?Falls - slick/wet surfacesFalling objects

Initial Atmospheric testing

Oxygen Oxygen meters

Electro-chemical detectors Instrument displays %

Oxygen Minimum 19.5% O2

(OSHA limit)Test oxygen first

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

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)

Additional atmospheric testing

After ventilating the spaceUpon first entryContinual monitoring if conditions could change Personal alarms (for entrants) Periodic re-testing

Instruments for confined spaces

Combination instruments commonly used Multi-gas, LEL, Oxygen

Instruments must be properly calibratedUsers must be trained

Ventilation

Inerting Inert gas displaces oxygen (to control flammable

hazard) IDLH hazard!

Natural ventilation Wind Convection

Ventilation

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

Ventilation

Air mover at openingPortable ventilation system

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

VentilationRecommended 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

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

Isolation

Tag and lock out circuits and linesDisconnect drives and linkagesSecure moving parts

Isolation

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

Bleed "

Ignition, electrical

Ignition control Non-sparking tools Classified electrical equipment ("Explosion proof")

Electrical control 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 Safety belt/harness, lanyards,

winch Required for top entry (OSHA)

Prepare for rescue before entry

Standby/Rescue

CommunicationsNever 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!

Confined Space Programs

Identify confined space hazards Find and

evaluate spaces Labels, signs

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

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

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

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

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

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

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

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)

OSHA, General Industry

Appendix A - Flow ChartAppendix B - Procedures for Atmospheric testingAppendix C - Examples of Confined Space ProgramsAppendix D - Sample PermitsAppendix E - Sewer System Entry