Transcript Slide 1

…..stay focus
Confined Space
Not designed for
continuous employee
occupancy Confined
space means a space
that has any of the
following
characteristics:
– limited openings for
entry and exit;
– unfavorable natural
ventilation;
– not designed for
continuous worker
occupancy.
It includes, but is not
limited to, boilers,
pressure vessels, cargo
holds, cargo tanks,
ballast tanks, double
bottoms, double hull
spaces, fuel oil, lube oil,
sewage-tanks, pumprooms, compressor
rooms, cofferdams, void
spaces, duct keels, interbarrier spaces and
engine crankcases.
– Large enough for an
employee to bodily enter
and perform assigned
work
– Has limited or restricted
means for entry or exit
Assess hazards, including Atmospheric hazards the may exist or be created in the confined space.
Determinate appropriate testing procedure, select and calibrate appropriate testing device.
Test for levels of oxygen, flammable, combustible and explosive agents and toxic substances
Can acceptable atmospheric levels by achieved and maintained, with or without purging and ventilating
Are flammable,
Combustible or
Explosive agents
Present?
NO
A
YES
Can confined
Space be rendered
Inert?
YES
Achieve and maintain
acceptable atmospheric
levels. Purge and
ventilate if necessary.
Are flammable, Combustible
Or Explosive agents
Present?
NO
YES
NO
Render inert and
monitor
Enter with appropriate
Precautions, respiratory
Protection and equipment
YES
Enter, test per plan
And maintain records
Is combustible dust
Airborne creating a
Hazard of explosion?
NO
YES
Entry not permitted
A
Go to
Chart 2
FROM CHART 1
Concentration of flammable or explosive
gas or vapors <5% LEL
NO
YES
NO
Concentration of oxygen
<23%
YES
HOT WORK
PERMITTE
HOT WORK NOT
PERMITTE
NO
Concentration of flammable
or explosive gas or vapor
<10% LEL
YES
COLD WORK
PERMITTE
COLD WORK NOT
PERMITTE
NO
ENTRY NOT
PERMITTE
Concentration of flammable or
Explosive gas or vapor
YES
INSPECTION
PERMITTE
CONFINED SPACE AWARENESS
• Data from the Bureau of Labor Statistics
indicate an average of 96 fatalities occurred
annually between 1992 and 2002, due to
oxygen deficient atmospheres. Confined
spaces are primary locations where oxygen
deficient and sometimes toxic atmospheres
develop. Information published by the
National Institute for Occupational Safety
and Health (NIOSH) indicates more than 60%
of confined space fatalities occur among
would-be rescuers. The following is provided
to prevent injuries and fatalities.
Permit-required Confined Space
• Contains or has the potential to contain a
hazardous atmosphere Contains a
material that has the potential to
overpower an entrant Has an internal
configuration that can trap an entrant,
asphyxiated by inwardly converging walls
or by a floor that slopes downward and
narrows to a small cross-section
Contains any other recognized safety or
health hazard
Non-permit Confined Space
• Does not contain atmospheric
hazards, or has the potential to
contain any hazard capable of
causing death or serious harm
(Note: Can become permit
space if hazards are brought
into it)
Confined Space Awareness at Campus
Locations & Field Research Centers
•
•
•
•
Atmospheric confined space hazards
include those due to oxygen deficiency
or the presence of toxic or
flammable/explosive gases
Physical confined space hazards
include those associated with
mechanical or electrical energy,
temperature, engulfment, falling
objects, and possibility of drowning
Examples of permit-required confined
spaces include sewers, septic tanks,
water tanks, unventilated vaults,
hoppers/ silos, and ventilation plenums
with fan motor/ blades
Examples of non-permit confined
spaces include storm drains, ventilated
vaults, concrete standpipes, attic/
basement crawl spaces, storage
containers, and irrigation/ pump sumps
Confined Space Entry & Rescue
• Only authorized and
trained employees
can participate in a
permit-required entry
• On-site rescue
capabilities must be
planned and in place
before permitrequired entry
CONFINED SPACES
INTRODUCTION/DEFINITION
Many different places require welding,
cutting, and heating work. Some of
these places lack room and become
“confined spaces.” Confined spaces
have the following characteristics:
– Limited space, entry, or exit.
– Poor ventilation—lack of safe breathing air
and possible buildup of hazardous gases,
fumes, and particles.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
EXAMPLES OF CONFINED
SPACES
Small rooms.
Storage tanks.
Process vessels.
Pipelines.
Pits
Sewers.
Tunnels.
Silos.
Vats.
Degreasers
Reactor vessels.
Boilers
Underground utility vaults.
Compartments of ships.
Unventilated corners of a room.
Ventilation and exhaust ducts.
Furnaces
REASONS FOR DEATHS AND SERIOUS INJURIES
FROM WELDING IN CONFINED SPACES
•
•
•
•
•
Fire.
Explosion.
Electric shock.
Asphyxiation.
Exposure to
hazardous air
contaminants.
ACTIONS REQUIRED BEFORE APPROVING START OF
WORK IN A CONFINED SPACE
CONFINED SPACES
• Fact Sheet No. 11—9/95 Page 1 of 3
• Test confined space atmosphere for (1) suitable oxygen content,
(2) no combustibles or reactive, (3) no toxics.
• Note: The testing requires special equipment and training. solate
lines by capping or double valving and venting, if feasible—keep
vents open and valves leak-free.
• Lock out all systems not required during welding, cutting, or
heating.
• Provide means for readily turning off power, gas, and other
supplies from outside the confined space.
• Protect or remove any hazardous materials or materials which
may become a physical or health risk when heated or exposed to
an arc
REQUIRED ACTIONS DURING
WORK IN A CONFINED SPACE
•
•
•
•
•
•
•
•
Continuously ventilate and monitor confined space to ensure that fumes
and
gases do not exceed safe exposure limits as found in OSHA (Occupational
Safety and
Health Administration) regulations Title 29, CFR Part 1910, 1000.
Use NIOSH/MSHA (National Institute for Occupational Safety and
Health/Mine Safety and Health Administration) approved breathing device
when required by code, instruction, or good practice.
Keep unnecessary persons and equipment out of and away from the
confined space.
Do not allow equipment to block exit or possible rescue efforts.
Place as much equipment as possible outside the confined space.
Do not go into a confined space unless a watchperson, properly equipped
and trained for rescue, is outside and maintaining continuous
communications with worker inside.
Provide means for turning off power, gases, and fuel from inside the
confined space, if feasible, especially if outside turn-off means are not
provided, feasible, or certain.
Classification of a Confined Space
How Can You Identify a Confined Space?
• NIOSH defines a confined space as one that, by design, has limited
openings for entry and exit, unfavorable natural ventilation that could
contain or produce dangerous air contaminants, and is not intended for
continuous employee occupancy.
• Confined spaces include but are not limited to storage tanks,
compartments of ships, process vessels, pits, silos, vats, wells, sewers,
digesters, degreasers, reaction vessels, boilers, ventilation and exhaust
ducts, tunnels, underground utility vaults, and pipelines.
• Confined spaces can be found in many industrial settings, from steel
mills to paper mills, from shipyards to farms, and from public utilities to
the construction industry. The hazards associated with confined spaces
can cause serious injury and death to workers. Two major factors lead to
fatal injuries in confined spaces:
– (1) failure to recognize and control the hazards associated with
confined spaces and
– (2) inadequate or incorrect emergency response. The emergency
response is usually a spontaneous reaction to an emergency
situation and can lead to multiple fatalities.
Examples of Confined Spaces
PIPELINE
SILO
STORAGE TANK
MANHOLE
DIGESTER
Confined spaces may be classified into
two categories:
– (1) open-topped enclosures with depths that restrict the natural movement of air
(e.g., degreasers, pits, selected types of tanks and excavations), and
– (2) enclosures with limited openings for entry and exit (e.g., sewers, tanks and
silo).
•
•
•
The hazards found in any confined space are determined by the material being
stored or used, by the process taking place inside the space, and by the effects of
the external environment. Worker entry into confined spaces may occur during
construction activities or during frequent necessary functions such as inspection,
repair or maintenance. For purpose of discussion, hazards in confined spaces are
separated into atmospheric hazards and physical hazards.
A confined space: has limited or restricted means of entry or exit is large enough for
an employee to enter and perform assigned work is not designed for continuous
occupancy
The hazards found in any confined space are determined by the material being
stored or used, by the process taking place inside the space, and by the effects of
the external environment. Worker entry into confined spaces may occur during
construction activities or during frequent necessary functions such as inspection,
repair or maintenance. For purpose of discussion, hazards in confined spaces are
separated into atmospheric hazards and physical hazards.
A confined space:
– has limited or restricted means of entry or exit
– is large enough for an employee to enter and perform assigned work
– is not designed for continuous occupancy
Limited Openings for
Entry and Exit
Confined space openings are limited primarily
by size or location. Openings are usually
small in size, perhaps as small as 18 inches
in diameter. An access door or portal that is
too small to allow an employee to walk
upright and unimpeded through it is
considered to be limited access or exit.
These small openings may make it very
difficult to get needed equipment in or out of
the spaces.
Not Designed for Continuous
Worker Occupancy
• Most confined spaces are not
designed for workers to enter
and work in them on a routine
basis. They are designed to
store a product, to enclose
materials and processes, or to
transport products or
substances. The distance an
employee must travel in a
space such as a tunnel to
reach a point of safety can be a
determinant for classifying as
space as a confined space.
Therefore, occasional worker
entry for inspection,
maintenance, repair, cleanup or
similar tasks is often difficult
and dangerous due to
chemical, distance or physical
hazards within the space.
• A confined space found in the workplace
may have a combination of the above
characteristics, which can complicate
working in and around these spaces, as
well as hamper rescue operations during
emergencies. If a survey of your working
area identifies one or more work spaces
with the characteristics listed above, then
please read the following information—
someday it may save your life or the life of a
co-worker.
How Can You Identify a PermitRequired Confined Space?
• A permit-required
confined space is one
that meets the
definition of a confined
space and has one or
more of these
characteristics:
contains or has a potential to contain a hazardous atmosphere contains a
material that has the potential for engulfing an entrant 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 recognized serious safety or
health hazard immediately dangerous to life and health that prevents selfrescue
What Are the Hazards
Involved in Entering
and Working in
Confined Spaces?
• Many workplaces contain spaces configured is
such a way to be considered “confined.”
Confinement itself may pose entrapment
hazards. Working in a confined space may
keep employees closer to hazards. For
example, confinement, limited access or
restricted airflow can result in hazardous
conditions that would not arise in an open
workplace.
Hazardous Atmospheres
•
•
Many substances have short-term exposure
limits, in addition to 8-hour time weighted
average exposure limits. The permit required
confined space rule is intended to protect
against short-term acute hazards. Exposures
at or below the permissible exposure limits
do not fall under the permit-required confined
space rule. Other standards (see 29 CFR
1910, Subparts G and Z) address a broader
range of health and safety concerns. Any
substance that is not capable of causing
death, incapacitation, impairment of ability to
self-rescue, injury or acute illness due to
health effects is not covered by the rule.
The atmosphere in a confined space may be
extremely hazardous because of the lack of
natural air movement. This characteristic of
confined spaces can result in:
– (1) oxygen-deficient
– (2) flammable
– (3) toxic atmospheres.
Oxygen-Deficient Atmospheres
•
•
•
•
An oxygen-deficient atmosphere has less than
19.5 percent available oxygen (O2). When
oxygen levels drop below 17 percent, there is
increased breathing volume, accelerated
heartbeat and a deterioration of night vision,
which is usually not noticeable. Oxygen
atmospheres with 14 to 16 percent oxygen
contribute to poor muscular coordination, rapid
fatigue and intermittent respiration. At 6 percent
oxygen, there is a rapid loss of consciousness
and death in minutes.
Any atmosphere with less than 19.5 percent
oxygen should NOT be entered without a
NIOSH-approved self-contained breathing
apparatus or a NIOSH-approved supplied air
breathing apparatus.
The oxygen level in a confined space can
decrease because of the type of work being
done, such as welding, cutting or brazing, or it
can be decreased by certain chemical reactions
(rusting) or through bacterial action
(fermentation).
The oxygen level is also decreased if oxygen is
displaced by another gas, such as carbon
dioxide, argon, helium or nitrogen. Total
displacement of oxygen by another gas, such
as carbon dioxide, will result in
unconsciousness, followed by death.
OXYGEN SCALE
23.50%
19.50%
O2 Enriched
Minimum for
safe entry
16%
Impaired judgment
and Breathing
14%
Faulty judgment
rapid fatigue
6%
Difficult breathing
death in minutes
Flammable Atmospheres
•
Flammable atmospheres generally result from
evaporation of flammable liquids, by-products of
chemical reactions, enriched atmospheres or
concentrations of combustible dusts. Two things make
an atmosphere flammable:
–
–
•
•
THE IGNITION TRIANGLE
AIR
(1) the amount of oxygen in air and
(2) a flammable gas, vapor or dust in the proper mixture.
Different gases and combustible dusts have different
flammable and explosive ranges. (See National Fire
Protection Association publication 497-1997,
Classification of Flammable Liquids, Gases, or Vapors
and of Hazardous (Classified) Locations for Electrical
Installations in Chemical
Process Area, and National Fire Protection
Association publication 499-1997, Recommended
Practices for Classification of Combustible Dusts and
of Hazardous (Classified) Locations for Electrical
Installation in Chemical Process). When a source of
ignition (for example, a sparking or electrical tool) is
introduced into a space containing a flammable
atmosphere, a fire or an explosion can result.
FLAMMABLE
ATMOSPHERE
GAS, VAPOR
OR DUST
SOURCE OF
IGNITION
• An oxygen-enriched atmosphere (above 23.5 percent) will cause flammable
materials, such as clothing and hair, to burn violently when ignited and may cause
some nonflammable materials to ignite. Therefore, NEVER use pure oxygen to
ventilate a confined space. Ventilate with normal air.
Toxic Atmospheres
Because air cannot freely move in and out of confined spaces due to the design
and configuration, the atmosphere inside a confined space can be very different
from the atmosphere outside. Deadly gases may be trapped inside, particularly if
the space is used to store or process chemicals or organic substances that may
decompose. There may not be enough oxygen inside the confined space to
support life, or the air could be so oxygen-rich that it is likely to increase the
chance of fire or explosion if a source of ignition is present.
Toxic atmospheres can be caused by the following:
The product stored in the space. The product may contain a toxic component, which could b absorbed into the walls and have the
potential for release depending on the use of the space.
The type of work being performed in a confined space. Examples of such include welding, cutting, brazing, painting, scraping,
sanding and degreasing. Toxic atmospheres are generated in various processes. For example, cleaning solvents are used in
many industries for cleaning/degreasing. The vapors from these solvents can build up to toxic levels in a confined space.
Areas adjacent to the confined space. Toxicant produced by work near confined spaces can enter and accumulate in confined
spaces. (Figure 4 illustrates work that may go on in confined spaces.)
General/Physical Hazards
In addition to the areas discussed above, evaluation of a confined space
should consider the following potential hazards:
Temperature Extremes
– Extremely hot or cold temperatures can present problems for workers. For
example, when possible, a steam tunnel should be allowed to cool before
entering.
Engulfment Hazards
– Loose granular material stored in bins and hoppers, such as grain, sand,
coal or similar material, can engulf and suffocate a worker. The loose
material can crust over, or bridge over, in a bin and break loose under the
weight of a worker.
The Hazard of Engulfment in
Unstable Material
Noise
•
Noise within a confined space can be amplified because of the design and acoustic properties of the
space. Excessive noise can not only damage hearing and reduce reaction time to hazards but can also
affect communication. This can cause a shouted warning to go unheard.
Slick/Wet Surfaces
•
Slips and falls can occur on a wet surface, causing injury or death to workers. Spaces that have an
internal configuration, inwardly converging walls, or a floor that slopes downward and tapers to a
smaller cross-section, increase the hazards of slipping and falling. Different material contained in the
space may react differently in a wet environment. A wet surface will also increase the likelihood for and
effect of electric shock in areas where electrical circuits, equipment and tools are used.
Falling Objects
•
Workers in confined spaces should be mindful of the possibility of falling objects, particularly in spaces
that have topside openings for entry and where work is being done above the worker
General Hazards
Work in confined and enclosed space has a greater likelihood of causing
fatalities, severe injuries and illness than any other type of shipyard
work or onboard ships.
• The key hazards associated with confined spaces are:
— serious risk of fire or explosion;
— loss of consciousness from asphyxiation arising from gas,
fumes, vapor or lack of oxygen;
— drowning arising from increased water level;
— loss of consciousness arising from an increase in body
temperature;
— asphyxiation/suffocation arising from free flowing solid
(engulfment) or the inability to reach a breathable atmosphere due to
entrapment.
• Surveyors will routinely enter confined spaces that are difficult to access
due to small and/or narrow openings. There may be physical
constraints within the space which need to be considered, and the
space itself may be cramped permitting only restricted mobility.
• Given the usual enclosed and darkened nature of a confined space this
activity ideally should not be carried out by personnel suffering from
phobias (e.g. claustrophobia) or who are susceptible to panic or anxiety
attacks.
General Hazards
Recognition of the inherent capacity of these spaces to harbor
hazardous agents is a significant element in any workplace
hazard assessment. When confined spaces are recognized to
be hazardous, provisions for minimizing the need for entry and
for use of appropriate work practices and equipment can be
made.
Access to open-topped spaces may require the use of ladders,
hoists or other devices. Escape from such areas may be very
difficult in emergency situations. Ladders and temporary,
movable, spiral or articulated stairs are usually considered
limited or restricted means of egress. Fixed industrial stairs
that meet OSHA standards must be considered limited or
restricted means of egress when the conditions or physical
characteristics of the space, in light of the hazards present in it,
would interfere with the entrant’s ability to exit or be rescued in
a hazardous condition.
A space has limited or restricted means of entry or exit if an
entrant’s ability to escape in an emergency would be hindered.
Two workers die from lack of oxygen
in confined space
• Two workers were repairing a process vessel
at a pulp mill. The valves to the vessel were
locked out, but a nitrogen supply to the power
boiler was not locked out because it had not
been identified in the lockout procedures.
Nitrogen gas inadvertently leaked from the
boiler system into lines that fed into the
process vessel, displacing the oxygen and
creating an IDLH (immediately dangerous to
life or health) atmosphere.
• The vessel was a confined space. Appropriate
confined space entry procedures to the vessel
had been followed on previous entries.
However, on this re-entry, the atmosphere was
not tested and the space was not ventilated.
One worker entered the vessel and collapsed
from oxygen deficiency. The second worker,
who had been watching outside the entrance
hole, was found collapsed with his head inside
the vessel.
Safe work practices
• Consider each entry to a confined
space to be potentially deadly. Proper
testing and safe entry procedures must
be followed for each entry.
• Identify and label confined spaces in
the workplace.
• Provide written safe work procedures
for entering a confined space and
ensure that workers are trained in these
procedures.
• Isolate the confined space from
adjacent piping by blanking, blinding, or
disconnecting the piping.
• Assess the hazards before entering a
confined space, including testing for
oxygen levels if necessary.
Note: This hazard alert is based on an
accident that occurred in 1997.
THE SILENT DANGERS OF
CONFINED SPACE
• Workers tend to put their faith in most indoor or confined
atmospheres, thinking someone else has checked for
safety. Air, whether life sustaining or killing, is usually
colorless, odorless, and tasteless. The atmosphere in a
confined space, for example, may seem like any other.
But that is one work place that must never be taken for
granted. Confined spaces have fooled scores of workers
killed or injured every year because they thought
someone had checked for safety or because they
“followed their noses” and guessed the air smelled OK.
The air may look safe and smell safe, yet be filled with
enough toxic contaminants to kill.