What is a Confined Space?
A confined space is a space with limited access, poor ventilation and not intended for permanent occupancy. Examples include tanks, silos, crawl spaces, pipework and pits. Work in these environments carries additional risks such as oxygen deficiency, explosion hazard or entrapment.
Working in a confined space requires specific safety measures, a valid work permit, and often pre-entry gas measurement.
🧠 Characteristics of a confined space
- Limited access
- A small opening or access hatch
- Often hard to reach or only accessible by ladder
- No or insufficient ventilation
- Risk of accumulation of gases or vapours
- Possibility of oxygen deficiency or excess nitrogen
- Temporary occupancy
- Entered only for inspection, cleaning, maintenance or repair
- Presence of hazardous substances or energy sources
- Explosion hazard (ATEX), chemical vapours, moving parts
🏭 Examples of confined spaces in industry
- Storage tanks (for chemicals or liquids)
- Silos or mixing vessels
- Sewerage or drainage systems
- Pipework, pipe tunnels or crawl spaces
- Boilers or heat exchangers
- Pits or manholes in plant rooms
Even relatively small or seemingly harmless spaces may qualify as confined spaces in the absence of ventilation or visibility.
🔍 Safety measures for confined-space work
| Measure | Explanation |
|---|---|
| Work permit | Mandatory, with a specific section for confined spaces |
| Gas measurement | O2, CO2, lower explosive limit (LEL), toxic substances |
| Lock-out Tag-out | Isolating and securing energy sources |
| PPE | Respiratory protection, harness, headlamp, fall arrest |
| Standby attendant | Person outside the space with means of communication |
| Rescue plan | Prepared in advance, including rescue equipment |
| Training | Specific instruction on risks and emergency procedures |
In ATEX zones, additional requirements apply, such as explosion-safe equipment and clothing.
🔐 Safety considerations
-
Risks:
-
Asphyxiation or oxygen deficiency
-
Intoxication from vapours
-
Explosion hazard
-
Falls or entrapment
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No communication or means of escape
-
Required:
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RI&E and task risk analysis (TRA)
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Monitoring of atmospheric gases (continuous measurement during prolonged work)
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Logging of access and continuous supervision
Entering a confined space without preparation is life-threatening and contravenes the Working Conditions Act.
📌 In summary
A confined space is a high-risk work environment that requires strict safety measures, training and preparation. Only approved and trained personnel may enter these spaces, after release via a work permit.