Confined Space Risk Assessment
A confined space is any space with limited entry or exit and not meant for continuous occupancy — like tanks, sewers, or silos. These spaces might seem harmless, but inside them lurk deadly risks like toxic gases, low oxygen, and the constant threat of getting trapped.
That’s why a confined space risk assessment isn’t optional — it’s life-saving. It’s a step-by-step process that helps identify potential hazards, assess the level of danger, and decide what precautions are needed before anyone sets foot inside.
Legal Standards and Guidelines
OSHA Confined Space Standard (29 CFR 1910.146)
This regulation defines permit-required confined spaces and outlines employer responsibilities for entry procedures, rescue planning, and hazard communication.
UK Confined Spaces Regulations 1997
UK law requires employers to avoid entry into confined spaces where possible. If entry is necessary, it must be done under strict safety conditions.
Indian Factory Rules and IS 3786
India mandates risk assessments, permits, supervision, and atmospheric testing before entering any confined space under Factories Act 1948 and IS standards.
Examples of Confined Spaces
Tanks and Silos
Often contain chemicals or grain — both can be hazardous or cause engulfment.
Sewers and Manholes
Dangerous due to presence of methane, hydrogen sulfide, and biological hazards.
Pipelines and Ducts
Narrow and poorly ventilated — oxygen deficiency and entrapment are major risks.
Underground Tunnels and Chambers
Remote, dark, and disorienting. Evacuation can be difficult during emergencies.
Common Hazards in Confined Spaces
Oxygen Deficiency or Enrichment
Less than 19.5% oxygen is unsafe. Too much oxygen (>23.5%) can cause materials to ignite easily.
Toxic or Flammable Gases
Gases like CO, H2S, or vapors from cleaning agents can kill silently.
Engulfment and Drowning
Loose materials or water can suddenly fill the space, trapping or suffocating the worker.
Heat Stress and Poor Ventilation
Trapped heat increases fatigue and the risk of collapse.
Restricted Entry and Exit
Delays rescue. If something goes wrong, there’s no easy way out.
When is a Confined Space Risk Assessment Required?
Before Entry or Permit Work
Every time someone enters a confined space, a fresh assessment is essential.
After Changes in Task or Environment
New tools, weather changes, or shift in contents can introduce new hazards.
During Emergency Situations
If rescue is required, the environment must be reassessed quickly for rescuers’ safety.
Key Components of a Confined Space Risk Assessment
Step 1 – Identify the Hazards
Consider chemical, physical, atmospheric, and operational hazards. Use gas detection equipment and inspect surrounding systems.
Step 2 – Identify People at Risk
Includes workers inside, attendants outside, and potential rescuers.
Step 3 – Evaluate the Risk and Apply Controls
Assign risk ratings and choose the most effective controls (starting from elimination down to PPE).
Step 4 – Document and Share the Plan
Use a structured format to record risks, controls, roles, and rescue procedures. Discuss it with the team.
Step 5 – Review and Revise Regularly
Any change — in procedure, weather, or structure — requires a fresh look at the risks.
Control Measures for Confined Space Entry
Permit to Work (PTW) System
No one should enter without an approved PTW that includes a checklist of hazards, controls, authorization, and rescue plan.
Atmospheric Testing and Monitoring
Test for oxygen, flammables, and toxic gases using calibrated multi-gas detectors.
Ventilation and Purging
Use fans or blowers to remove harmful gases and bring in fresh air. Purge with inert gas if necessary.
Rescue Plan and Standby Person
Have a trained standby person at the entry point. Rescue gear — like tripods, winches, and SCBA — must be ready.
Communication and Signage
Maintain constant communication between entrant and standby. Place warning signs and restrict access to authorized personnel only.
Hierarchy of Controls in Confined Spaces
Elimination – Avoid Entry if Possible
Can inspection or cleaning be done with CCTV or robots?
Substitution – Use Robots or Extend Tools
Replace human entry with mechanical devices wherever feasible.
Engineering Controls – Fans, Barriers
Control the atmosphere or prevent unauthorized access.
Administrative Controls – Entry Permit, Training
Ensure only competent, trained people carry out the work.
PPE – SCBA, Harnesses, Helmets
Used only when higher-level controls can’t eliminate the risk.
Safety Tips for Confined Space Work
Conduct Toolbox Talk
Brief your team on the risk assessment, emergency plan, and safety gear.
Always Test Before You Enter
Atmospheric conditions can change fast. Test just before and during the work.
Never Work Alone
Always have a buddy and a trained standby person ready to assist or rescue.
Confined Space Risk Assessment Template
Sample Fields and Format
- Location and task
- Hazards identified
- Atmospheric test results
- Control measures
- Names of authorized entrants and attendants
- Rescue plan and equipment
- PTW number and validity
- Supervisor’s signature
How to Apply It On-Site
Conduct assessment before entry. Use it during toolbox talks. Display it near the confined space. Review it after every job or incident.
Confined Space – Risk Assessment
General Information
- Project/Site Name: GreenFuel Oil & Gas Ltd. – Tank Cleaning Operation
- Assessment Title: Risk Assessment for Confined Space Entry
- Location: Crude Oil Storage Tank No. 3
- Assessed By: Mahendra Lanjewar (Safety Officer)
- Assessment Date: 01 July 2025
- Review Date: 01 October 2025
- Activity Description: Internal cleaning and inspection of crude oil storage tank involving confined space entry by workers.
Confined Space Risk Assessment Table
| Task | Hazards Identified | Persons at Risk | Risk Rating (Before Control) | Control Measures | Risk Rating (After Control) | Responsible Person |
|---|---|---|---|---|---|---|
| 1. Entry into confined tank | Oxygen deficiency / toxic gas exposure | Workers entering tank | High | – Conduct atmospheric testing (O2, H2S, CO) – Ventilate space using blowers – Use calibrated gas detectors – Issue confined space entry permit | Low | Safety Officer / Supervisor |
| 2. Ignition of flammable vapors | Explosion or fire inside tank | Entrants and attendants | High | – Use intrinsically safe lighting – Eliminate all ignition sources – Ensure tank is gas-free – Use ATEX-approved tools and PPE | Low | Safety Officer / Permit Issuer |
| 3. Collapse or engulfment | Worker trapped or suffocated by sludge | Entrants inside tank | Medium | – Remove sludge before entry – Use harness and tripod system – Assign trained standby person | Low | Confined Space Supervisor |
| 4. Communication failure | Delay in rescue or response | Entrants and standby workers | High | – Use two-way radios or lifeline signals – Maintain visual contact – Assign one standby person per entry point | Low | Attendant / Safety Officer |
| 5. Inadequate emergency response | Entrant becomes unconscious or trapped | Entrant | High | – Develop and practice rescue plan – Keep rescue equipment ready (tripod, winch, SCBA) – Train rescue team – Notify emergency services | Medium | Safety Officer / First Aider |
| 6. Heat stress or exhaustion | Dehydration, fatigue inside tank | Entrants | Medium | – Limit work duration (rotation every 30 mins) – Provide cool water and ventilation – Monitor for signs of fatigue or dizziness | Low | Supervisor / Paramedic |
| 7. Inadequate training or competence | Improper use of PPE or violation of entry rules | All confined space workers | High | – Provide confined space training – Use only authorized personnel – Conduct toolbox talk before shift | Low | Project Manager / HSE Trainer |
Risk Rating Matrix
| Severity | Likelihood | Risk Rating |
|---|---|---|
| 1 – Minor injury | 1 – Unlikely | Low |
| 2 – Lost time injury | 2 – Possible | Medium |
| 3 – Major/fatal injury | 3 – Likely | High |
Note: Risk Rating = Severity × Likelihood
Additional Notes
- Permit to Work: Confined Space Entry Permit is mandatory before starting the task.
- PPE Required: Full-body harness, SCBA (where required), flame-resistant clothing, gas detector, helmet with lamp, antistatic gloves, safety boots.
- Monitoring Required: Continuous atmospheric monitoring throughout the task.
- Rescue Equipment: Tripod, lifeline, retrieval winch, SCBA sets, first aid kits.
- Rescue Team: Must be trained and on standby throughout the operation.
Review and Sign-Off
| Name | Designation | Signature | Date |
|---|---|---|---|
| Rupesh Wasnik | Safety Officer | [Signature] | 01-07-2025 |
| Ramesh Nair | Project Manager | [Signature] | 01-07-2025 |
| Sandeep Kulkarni | Confined Space Supervisor | [Signature] | 01-07-2025 |
Conclusion
Confined spaces are deceptive — quiet and tight on the outside, but dangerously unpredictable inside. One small oversight can turn deadly. That’s why a confined space risk assessment isn’t just a paper requirement — it’s your safety backbone. Identify. Evaluate. Control. Communicate. Review. Because safety inside confined spaces starts well before anyone steps in.
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FAQs
1. What qualifies as a confined space?
A space with restricted entry/exit, not meant for continuous occupancy, and poses risk — like tanks, sewers, or pipelines.
2. Who is allowed to enter a confined space?
Only trained and authorized personnel with valid permits and under supervision.
3. What gases are commonly found in confined spaces?
Common dangers include hydrogen sulfide (H2S), carbon monoxide (CO), methane (CH4), and oxygen deficiency.
4. Is a permit always required?
Yes — a permit to work is mandatory for all permit-required confined spaces.
5. What is the role of the standby person?
The standby or attendant monitors the entrant, maintains communication, and initiates emergency rescue if needed.
