Confined Spaces Hazards. Part-02.
- Confined Spaces Safe Work Practices.
- Anticipate/recognize/respond.
Hazards must be identified on the CSE permit.
Check for:
Chemical hazards.
Acceptable oxygen levels.
Hazards that may entrap/bury.
Other recognized hazards, stored energy, noise, or
temperature hazards.
- Hazards evaluation.
Hazards identified on
the CSE permit.
Test before and
during occupancy for:
Oxygen levels.
Air contaminants.
Flammable gases and vapors.
Mechanical and electrical equipment.
Ability to perform
safe work practices.
Operability of safety
systems
Other hazards.
- Oxygen test.
Oxygen is necessary to sustain life.O2 levels should be between 19.5% and
23.5%.
Test first for O2:
If oxygen deficient <
19.5 % use air- supplied equipment.
If oxygen enriched >
23.5 %, ventilate space until safe.
- Test for flammability and potential for explosion.
Certain gases and vapors may ignite or explode under the
right conditions.
Test the flammable limits.
Use safe/non-sparking instrument to test the LFL. No entry is permitted if a space contains flammable gas, vapor, or mist in excess of 10% of its LFL. Ventilate space to achieve a safe level before entry.
- Air contamination test.
Check air contaminants After identifying oxygen level [e.g.,
CO, H2S]).
Check safety data sheets.
Test the atmosphere with appropriate equipment.
Control exposure to ensure safety.
- Hazard control systems.
Control systems include:
- Isolation.
To control/remove potentially hazardous substances or other
hazards from the confined space.
- LOTO.
Lockout and tagout/control of hazardous energy (LOTO/COHE)
procedures to isolate hazardous energy such as electrical, pneumatic,
hydraulic, or mechanical energy.
- Blanking.
Blanking, or disconnecting, and capping lines that may empty
into the permit space.
- Bleeding.
Bleeding blanked or
isolated equipment to prevent contents from emptying into the permit space.
- Safe atmosphere.
Ventilate the permit space with fresh air to remove air
contaminants and provide a safe atmosphere.
- Flushing.
Flush the space with liquid such as water to remove or
dilute toxic or corrosive liquids and residues.
- Purge Explosive Vapors.
Purge the space with an inert gas such as carbon dioxide or
nitrogen to control potentially flammable/ explosive vapors and gases.
- External hazard control.
External hazards include:
falling materials/equipment and vehicle or generator exhaust entering space.
Control Methods:
Restrict unauthorized
personnel.
Use barricades/flags
to warn of potential hazard.
Post permit.
- CSE equipment.
Permit equipment:
- Air monitoring and testing.
Monitoring equipment must measure the hazards such as:
Oxygen, flammability, air contaminants, radiation, and
extreme temperatures.
Equipment must be intrinsically safe.
You must be familiar with operation, interpretation, and
calibration. Take note of alarms on equipment; and follow manufacturer’s
instructions.
- Communications equipment.
Factors to be considered when choosing a communication
system:
The size and shape of confined space, the number of entrants,
the lighting, and other factors.
Systems may include voice, hand signals, walkie talkies,
radios, and horns and alarms.
If flammable vapors or gases are present use intrinsically
safe equipment.
- PPE.
PPE is equipment that protects head, ace, eyes and ears,
respiratory protection, hands and feet, feet, and whole-body protection.
You should consider engineering and work practice controls
first, conduct PPE hazard assessment, select PPE based upon known and
anticipated hazards, PPE must meet industry standards, and get PPE training.
- Respiratory protection.
Two principal types:
Supplied air respirators, used in:
Oxygen-deficient environments, DLH environments, and
atmospheres with high levels of air contaminants.
Air-purifying respirators
Filter out contaminants at generally lower levels, do not
supply oxygen, and are color-coded to identify chemical protection.
- Rescue equipment.
Varies with entry type, hazard, and space. Rescue equipment
may include:
PPE, SCBA, full-body harness with lifeline, emergency
extraction equipment, tripod, pulley, winch, or hoist, other equipment (First
Aid).
- Training Requirements.
The employer must provide training to each employee whose
work is regulated by this standard, at no cost to the employee, and ensure that
the employee possesses the understanding, knowledge, and skills necessary for
the safe performance of the duties assigned under this standard.
This training must result in an understanding of:
The hazards in the permit space
Methods used to isolate, control or in other ways protect
employees from these hazards.
For those employees not authorized to perform entry rescues,
in the dangers of attempting such rescues.
Training must be provided to each affected employee:
1. In both a language and vocabulary that the employee can
understand.
2. Before the employee is first assigned duties under this
standard.
3. Before there is a change in assigned duties.
4. Whenever there is a change in permit space entry
operations that presents a hazard about which an employee has not previously
been trained.
5. Whenever there is any evidence of a deviation from the
permit space entry procedures required or there are inadequacies in the
employee’s knowledge or use of these procedures.
The training must establish employee proficiency in the
duties required and must introduce new or revised procedures, as necessary, for
compliance with this standard.
The employer must maintain training records to show that the
training required has been accomplished.