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Confined Space Entry Program

Environmental Health and Safety

  1. DEFINITIONS

3.1 CONFINED SPACE

A space defined by the concurrent existence of all of the following conditions:

  • Large enough and so configured that an employee can bodily enter and perform assigned work.
  • Has limited or restricted means for entry or exit.
  • Is not designed for continuous employee occupancy.
  • Examples of confined spaces at UT Tyler include manholes, boilers, tanks, vats, sewer pipelines, and vaults without existing general ventilation.

 Note: Trenches typically are not confined spaces, check applicable state and federal OSHA regulations for trench operations requirements. 

3.1.1. NON-PERMIT CONFINED SPACE

A confined space is any space that does not contain or, with respect to atmospheric hazards, have the potential to contain any hazard capable of causing death or serious physical harm.

3.1.2. PERMIT REQUIRED CONFINED SPACE

            A confined space that has one or more of the following characteristics:

    • Contains or has the potential to contain a hazardous atmosphere.

Note: Permit procedures are not required where existing ventilation is sufficient to remove potential dangerous air contamination.

    • Contains a material that has the potential for engulfing an entrant.
    • Ready removal of a suddenly disabled employee is difficult due to the location and/or size of access openings.
    • Contains any other recognized serious safety or health hazard. 

3.2 ENCLOSED SPACE

Spaces that do not meet the definition of a confined space, but may require precautionary measures upon entering are defined as enclosed space.  Examples of enclosed spaces at UT Tyler are crawl spaces and service tunnels with existing general ventilation. 

3.3 DANGEROUS AIR CONTAMINATION

An atmosphere capable of causing death, injury, acute illness, or disablement due to the presence of flammable, explosive, toxic, or incapacitating substances.

3.4 IMMEDIATELY DANGEROUS TO LIFE OR HEALTH (IDLH)

An atmosphere that poses an immediate threat of loss of life: May result in irreversible or immediate severe health effects; may result in eye damage/irritation; or other condition that could impair escape from a confined space.

3.5 OXYGEN DEFICIENT/OXYGEN ENRICHED ATMOSPHERE

An oxygen deficient/enriched atmosphere is defined as containing less than 19.5% or greater than 23.5% oxygen by volume.

% O2

Observed Symptoms

19.5

Minimum acceptable oxygen level.

15–19

Decreased ability to work strenuously.

Impaired coordination.  Early symptoms.

12-14

Respiration increases.  Poor judgment.

10-12

Respiration increases.  Lips blue.

8-10

Mental failure,  Fainting, Nausea, Unconsciousness. Vomiting.

6-8

8 minute exposure - fatal 

6 minute exposure - 50% fatal      

4-5 minute exposure - possible recovery.

4-6

Coma in 40 seconds.  Death

3.6 PERMISSIBLE EXPOSURE LEVEL (PEL)

The PEL is total exposure to a toxic substance that an employee is allowed to receive in any 8-hour work day as defined by OSHA.

3.7 THRESHOLD LIMIT VALUE-TIME WEIGHTED AVERAGE (TLV-TWA)

Established by the American Conference of Government Industrial Hygienists; the time weighted average concentration for a normal eight hour work day and a forty hour work week, to which all workers may be repeatedly exposed, day after day, without adverse effect.

3.8 TRESHOLD LIMIT VALUE-SHORT TERM EXPOSURE LIMIT (TL V-STEL)

The concentration to which workers can be exposed continuously for 15 minutes without suffering from irritation, chronic or irreversible tissue damage, narcosis of sufficient degree to increase the likelihood of accidental injury, impair self-rescue, or materially reduce work efficiency, provided that the daily TL V- TW A is not exceeded.  Each 15 minute excursion is followed by a one-hour rest period in clean air and only four (4) excursions are allowed per day. 

3.9 THRESHOW LIMIT VALUE-CEILING VALUE (TL V-C)

TLV-C is the concentration that must not be exceeded during any part of the working exposure. 

3.10 LOWER EXPLOSIVE LIMIT (LEL)

The LEL is the lowest concentration of a vapor that produces a flash of fire when an ignition source (heat, arc, or flame) is present.  At concentrations lower that the LEL, the mixture is too "lean" to burn. 

3.11 UPPER EXPLOSIVE LIMIT (UEL)

The UEL is the highest concentration of a vapor in air that will produce a flash of fire when an ignition source (heat, arc, or flame) is present. At concentrations higher than the UEL, the mixture is too "rich" to bum.

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