mod 1.2 Flashcards
Is large enough for an employee to enter fully and perform assigned work;
Confined space
Is not designed for continuous occupancy by the employee; and
Confined space
Has a limited or restricted means of entry or exit.
Confined space
Two Categories of Confined Space
-Open-topped enclosures with depths which restrict the natural circulation of air
-Enclosures with limited opening for entry and exit
PRCS
Permit-Required Confined Space
Is considered to have occurred when any part of a person’s body
crosses the plane of an opening into the space.
Confined space entry
Common Confined Space Hazards
(6)
- Oxygen deficiency
- Oxygen-enriched atmosphere
- Flammable/Explosive Atmospheres
- Toxic Atmospheres
- Temperature extremes
- Physical Hazards (noise, slip, trip, falls, falling objects, equipment, electrical)
Is a leading cause of death among workers entering confined spaces
Lack of oxygen
cannot be detected by sight or smell.
Low oxygen level
Oxygen is used up when metals rust. t/f
True
Oxygen is not used up during combustion. t/f
False
Oxygen can be replaced by other gases. t/f
True
Micro-organisms use up oxygen. t/f
True
Minimum acceptable oxygen level
19.5%
Decreased ability to work strenuously. Impaired coordination. Early symptoms
15-19%
Respiration increases. Poor judgment
12-14%
Respiration increases. Lips blue.
10-12%
Mental failure. Fainting. Nausea. Unconsciousness. Vomiting
8-10%
Coma in 40 seconds. Death
4-6%
8 minutes - fatal
6 minutes - 50% fatal
4-5 minutes - possible recovery
6-8%
Too much oxygen greatly increases the risk of fire or explosion
in the confined space.
t/f
True
Common toxic gases in confined space:
Hydrogen Sulfide, Carbon Monoxide
Whenever unstable solids made of small particles like sand or grain are stored in enclosures,
there is a danger of the materials flowing onto workers and trapping or burying them.
Loose and unstable materials
The space you are about to enter may have a hatchway that is difficult to squeeze through, and
ladders for ascending or descending.
Slips, trip and fall hazards
You are therefore at risk of falling while getting into the
space as well as while you are inside. In addition, the flooring of tanks or other wet environments
or the rungs of a ladder may be very slippery.
Slips, trip and fall hazards
In a confined space there may be the danger of being struck by falling objects such as tools or
equipment, particularly if access ports or workstations are located above workers.
Falling objects
Mechanical equipment such as augers, mixers, or rotating tanks can be dangerous if activated or
not secured.
Moving parts of equipment and machinery
Residual energy, such as gravity or accumulated pressure, may also pose a risk
unless the equipment is locked out and de-energized.
Moving parts of equipment and machinery
All electrical sources that pose a hazard to workers inside the space must be locked out following
the written lockout procedure for the particular confined space.
Electrical shock
Piping adjacent to a confined space could contain liquids or gases or other harmful substances.
Substances must be prevented from entering the confined space through piping. This is done by
“isolating” the piping from the confined space.
Substances entering through piping
Emergency lighting such as flashlights or battery-operated area units must be provided where
necessary, so that workers can locate exits and escape.
Poor visibility
produced in confined spaces can be particularly harmful because of reflection off walls
Noise
Confined spaces should be fully drained or dry when entered. Spaces that are not fully drained
or dry may pose a——————
Risk of drowning
Basic Principles of Confined Space Safety:(3)
- Avoid confined space entry
- Establish Safe systems of work
- Prepare Emergency plans
lighter than air
Methane
same as air
Carbon monoxide
heavier than air
Hydrogen sulfide
Order of Gas Testing:
(4)
- Oxygen
- Flammable gases
- Toxic gases
- Others
Testing Points:
a. Bottom
b. Middle
c. Top
Things to consider in Emergency Planning:(6)
• Communications
• Liaison and rescue
• Shutdown
• First Aid Procedures
• Drills
• Emergency services contact
