OBJECTIVES
Upon completion of this lesson, you will be able to:
- Define confined space.
- List the types of confined space.
- Describe the hazards of confined space.
- Define the confined space entry procedure.
Confined Space
A place that is narrow or closed and there is not enough route of access or egress for rescuers, and they have to face different types of hazards is called confined space.
Examples:
- Storage tanks
- Sewers
- Underground tunnels
- Silos
Types of Confined Space
A. Required Permit for Entry
A Permit-required confined space is a confined space that has one or more of the following characteristics:
- Contains or has the potential to contain a hazardous atmosphere
- Contains a material that could engulf an entrant
- Has inwardly converging walls or a floor that slopes downward, tapering to a small cross-section
- Contains any other recognized serious safety or health hazard
B. Without Permit
The confined space which has minor hazards and does not require a formal permit for entry is called a non-permit confined space.
Examples:
- Boilers and Furnaces
- Pipelines
- Pits
- Process Vessels
- Silos and Storage Tanks
- Sewers and Manholes
- Trenches and Excavations
Hazards of Confined Space
- Atmospheric
- Physical Configuration
- Mechanical
- Electrical
- Thermal
- Noise
- Vibration
Atmospheric Hazards
- Oxygen Deficient Atmospheres (O₂ < 19.5%)
- Oxygen Enriched Atmospheres (O₂ > 23.5%)
- Flammable Atmospheres (Presence of gases like methane, hydrogen)
- Toxic Atmospheres (Exposure to chemicals like hydrogen sulfide, carbon monoxide)
- Corrosive Atmospheres (Chemicals that can damage lungs/skin)
- Asphyxiating Atmospheres (Displacement of oxygen by inert gases)
Note: In the atmosphere, the most important factor is oxygen, and its amount should not be less than 19.5%.
Physical Configuration Hazards
The use and shape of a space can create hazardous conditions:
- Use of Ladders
- Wet or slippery surfaces
- Uneven bottoms
- Bends in tunnels
- Narrow areas that can entrap workers
- Poor lighting
- Use retrieval & fall protection equipment
Mechanical Hazards
Some confined spaces have unguarded mechanical equipment such as:
- Rotating blades
- Mixers
- Conveyors
- Pressurized systems
Safety Measure:
All equipment must be Locked Out and Tagged Out (LOTO) before entry.
Electrical Hazards
Electric shock is a possible hazard in confined spaces.
Hazard Sources Include:
- Broken lighting
- Electrical sensing devices
- Limit switches
- Level indicating devices
- Hazards from equipment taken inside
Thermal Hazards
High and low temperatures are hazards:
- Burns (from hot surfaces or steam)
- Frostbite (in cold storage spaces)
- Heat Stress (due to lack of ventilation)
Note: Wearing protective clothing can increase heat stress on a worker.
Noise Hazards
Noise creates a hazard by:
- Causing hearing loss
- Preventing communication
- Lowering worker’s effectiveness
Prevention:
- Eliminate noise sources before entry
- Use proper hearing protection (earplugs or earmuffs)
Vibration Hazards
- Vibration of the body can cause damage to joints and muscles
- Using vibrating tools can cause damage to fingers & hands (e.g., “white finger syndrome”)
Prevention:
- Eliminate equipment vibrations before entry
- Use vibration-dampening tools & gloves
Confined Space Entry Procedure
All entrants, supervisors, and attendants must be fully qualified.
Steps:
- Conduct Pre-Entry Briefing (Discuss hazards, roles, and emergency procedures)
- Assemble and check equipment (Gas detectors, harnesses, PPE)
- Establish Acceptable Entry Conditions (Safe oxygen levels, no toxic gases)
- Conduct Initial Air Sampling (Test for hazardous gases)
- Execute & Complete Entry Permit (Document authorization)
- Station Entry Attendant (Monitor conditions and assist if needed)
- Establish Monitoring of Atmosphere (Continuous gas detection)
- Establish Communication (Two-way radios or signals)
- Execute Hot Work Permit (if applicable) (For welding, cutting, etc.)
- Post Confined Space Entry Permit (Visible at entry point)
- Enter Space (Follow safety protocols)
- Post-Entry Debrief (if problems were encountered) (Review incidents and improve procedures)
Final Words:
Confined spaces pose serious risks, including atmospheric, mechanical, and physical hazards. Proper identification of permit-required and non-permitted spaces is crucial for safety. Workers must follow strict entry procedures—pre-entry checks, air monitoring, permits, and PPE—to prevent accidents.
Understanding hazards like oxygen deficiency, toxic gases, and engulfment risks ensures compliance with safety standards.
Continuous training, hazard awareness, and emergency preparedness save lives. Always prioritize safety protocols to mitigate risks in confined space operations. Stay vigilant, follow regulations, and ensure a safe work environment for all personnel.
Jordan Hayes, a rescue professional with years of hands-on experience, shares expert insights and tips to enhance safety and preparedness on arescuers.com