Confined space work is one of the most hazardous activities in many industries. This guide covers the essential safety procedures for safe confined space entry.
What is a Confined Space?
A confined space is an enclosed or partially enclosed area that:
- Is not designed for continuous human occupancy
- Has limited or restricted entry and exit
- May have an atmosphere that could be hazardous
Common examples include tanks, silos, pits, trenches, sewers, vessels, and storage containers.
Hazards in Confined Spaces
Confined spaces present unique and serious hazards:
Atmospheric Hazards
- Oxygen deficiency – Levels below 19.5% can cause impairment or death
- Oxygen enrichment – Levels above 23.5% increase fire and explosion risk
- Toxic gases – Carbon monoxide, hydrogen sulfide, methane, and others
- Flammable atmospheres – Risk of fire or explosion
Physical Hazards
- Engulfment by liquids or loose materials
- Entrapment in converging walls or equipment
- Falls from height or on slippery surfaces
- Mechanical hazards from equipment and moving parts
- Electrical hazards
Environmental Hazards
- Extreme temperatures
- Noise
- Poor lighting
- Difficult communication
Before Entry: Planning and Risk Assessment
Never enter a confined space without proper planning:
1. Is Entry Necessary?
- Can the work be done from outside the space?
- Can the space be modified to eliminate the need for entry?
2. Risk Assessment
- Identify all potential hazards
- Consider previous contents and residues
- Review adjacent processes that may affect the space
- Determine control measures required
3. Permit to Work
- Implement a formal permit-to-work system
- The permit documents hazards, controls, and approvals
- All parties must understand and sign off
4. Emergency Procedures
- Plan rescue procedures before entry
- Ensure rescue equipment is available and workers trained
- Never attempt rescue without proper equipment and training
Control Measures During Entry
Atmospheric Monitoring
- Test the atmosphere before entry
- Continuously monitor during work
- Use calibrated, appropriate gas detectors
- Know the action levels for each hazard
Ventilation
- Provide mechanical ventilation to maintain safe atmosphere
- Never use pure oxygen to ventilate
- Position ventilation to effectively circulate air
Isolation
- Lock out and tag out all energy sources
- Isolate pipework, electrical, and mechanical systems
- Use blanking plates or physical disconnection where required
Access and Egress
- Ensure safe means of entry and exit
- Keep entry points clear at all times
- Use appropriate ladders, platforms, or hoisting equipment
Standby Person
- A trained standby person must be stationed at the entry point
- They must maintain communication with workers inside
- They must be able to summon rescue if needed
- They must not enter the space to attempt rescue
Emergency Response
If an incident occurs:
- Do not rush in – Untrained rescuers become additional casualties
- Alert emergency services and rescue team
- Ventilate the space if safe to do so
- Use supplied air rescue equipment if available
- Provide first aid once the casualty is removed safely
Training Requirements
All workers involved in confined space work must be trained:
- Hazard identification and risk assessment
- Use of atmospheric monitoring equipment
- Emergency procedures and rescue equipment
- First aid and CPR
Key Takeaways
- Confined spaces kill – treat every entry as potentially life-threatening
- Always test the atmosphere before and during entry
- Never enter without a permit and proper controls in place
- Have a rescue plan and trained personnel ready
- Consider whether entry is necessary at all
Need confined space documentation? Browse our WHS forms for permit templates and checklists.