11 Apr Confined Space Safety

Confined Space Safety

Working in a confined space can expose employees to serious and potentially fatal hazards. A confined space is generally large enough for an employee to enter and perform work, has limited or restricted means of entry or exit, and is not designed for continuous employee occupancy.

Some confined spaces may also be permit-required confined spaces because they contain, or have the potential to contain, hazardous atmospheres, engulfment hazards, configurations that could trap or asphyxiate an entrant, or other recognized serious hazards.

Never enter a confined space unless it has been evaluated, required entry procedures are in place, and you are authorized and trained to enter.

Guide for Discussion

Primary Hazards

Confined-space hazards may include:

• Oxygen-deficient or oxygen-enriched atmospheres.
• Toxic gases, vapors, fumes, or other airborne contaminants.
• Flammable or explosive atmospheres.
• Engulfment by liquids or flowing materials.
• Mechanical, electrical, hydraulic, pneumatic, or other hazardous energy.
• Configuration hazards that could trap or suffocate an employee.
• Heat, noise, falls, and other physical hazards associated with the work being performed.

Never rely on sight or smell to determine whether an atmosphere is safe.

Atmospheric Testing and Monitoring

Before entry, the atmosphere must be tested using properly calibrated equipment appropriate for the hazards that may be present.

Atmospheric testing should generally be performed in this order:

1. Oxygen concentration.
2. Flammable gases and vapors.
3. Potential toxic contaminants.

Continue atmospheric monitoring as required throughout the entry. Conditions inside a confined space can change rapidly because of the work being performed or changes occurring outside the space.

If monitoring indicates an unsafe condition, entrants must leave the space immediately and the hazard must be evaluated before re-entry.

Ventilation

Forced-air ventilation may be necessary to establish and maintain a safe atmosphere.

• Use clean air from an uncontaminated source.
• Position ventilation equipment so contaminants are effectively removed or diluted.
• Continue ventilation as necessary while employees occupy the space.
• Never use oxygen to ventilate a confined space.
• Ensure ventilation equipment is appropriate for any potentially flammable or explosive atmosphere.

Ventilation does not eliminate the need for required atmospheric testing and monitoring.

Entry Procedures

Before entering a permit-required confined space:

• Identify and evaluate the hazards.
• Isolate the space from hazardous energy and materials.
• Complete the required entry permit.
• Test the atmosphere.
• Establish required ventilation and other controls.
• Provide appropriate PPE and respiratory protection when required.
• Establish reliable communication between entrants and the attendant.
• Prevent unauthorized persons from entering.
• Have required rescue procedures and equipment ready before entry begins.

The attendant must remain outside the permit space and continuously perform assigned attendant duties while entry operations are underway.

Confined Space Rescue

Never enter a confined space to rescue another employee unless you are part of an authorized and properly equipped rescue operation.

Many confined-space fatalities involve would-be rescuers who enter without understanding the hazard and are overcome by the same conditions as the original victim.

Rescue procedures must be established before entry begins. Non-entry rescue should be used whenever feasible, with appropriate retrieval systems provided when required. Employees assigned rescue duties must have the necessary training, equipment, and ability to perform the rescue safely.

If an entrant becomes distressed or conditions become unsafe, immediately initiate the established emergency and rescue procedures.

Remember

A confined space may look harmless while containing an atmosphere or other hazard capable of causing unconsciousness or death within minutes. Never enter based on assumptions. Follow the confined-space entry procedure, test and monitor the atmosphere, maintain required controls and communication, and never attempt an unauthorized rescue.