Wednesday, September 27, 2023




This risk assessment for Septic tank cleaning written by HSE Documents often hidden underground or within tight enclosures, poses fatal and critical threats and dangers to workers. Various environmental factors such as hazardous gases, limited ventilation, and the potential for engulfment or entrapment make this job one of the most hazardous in the field of sanitation. This article Risk Assessment for Septic Tank Cleaning written by HSE Documents delves into the complexities of confined space entry and emphasizes the importance of meticulous risk assessment protocols.

1.0. Hazard

1.1. Unfit/ untrained operatives

1.2. Limited access and Exit. Fall of Person/ Materials

1.3. Oxygen deficiency/ enrichment, lack of ventilation.

1.4. Flammable / Toxic gases

1.5. Hot Work

1.6. Lack of Lights & Communication Facility

1.7. High Temperature/ Humidity

2.0. Harm and Consequences

2.1. Asphyxiation:

2.1.1. Harm: Lack of oxygen (hypoxia) within a confined space can result in asphyxiation, leading to unconsciousness and death.

2.1.2. Consequences: Individuals can lose consciousness rapidly, making self-rescue or rescue by others extremely challenging. Fatalities can occur if prompt action is not taken.

2.2. Toxic Atmospheres:

2.2.1. Harm: Confined spaces may contain hazardous gases or chemicals that can cause harm when inhaled, ingested, or absorbed through the skin.

2.2.2. Consequences: Exposure to toxic substances can lead to acute or chronic health issues, including respiratory problems, chemical burns, or long-term illnesses. It can also result in fatalities.

2.3. Fire and Explosion:

2.3.1. Harm: Confined spaces may contain flammable gases, vapors, or dust that can ignite and cause fires or explosions.

2.3.2. Consequences: Fires and explosions can result in severe burns, traumatic injuries, and fatalities. Additionally, they may damage equipment and structures.

2.4. Engulfment:

2.4.1. Harm: Workers can be engulfed by solid or liquid materials (e.g., grain, water, sand) within a confined space.

2.4.2. Consequences: Engulfment can lead to suffocation, drowning, or traumatic injuries. The victim may become trapped, making rescue difficult.

2.5. Mechanical Hazards:

2.5.1. Harm: Confined spaces may contain moving equipment, machinery, or rotating parts that can cause physical harm.

2.5.2. Consequences: Workers can suffer crush injuries, entanglement, or amputations if they come into contact with moving parts.

2.6. Falls:

2.6.1. Harm: Working at heights or on unstable surfaces within confined spaces can lead to falls.

2.6.2. Consequences: Falls can result in fractures, head injuries, and fatalities, especially if appropriate and essential fall protection initiatives are not in place.

2.7. Entrapment:

2.7.1. Harm: Individuals working in confined spaces may become trapped due to structural failures or equipment malfunctions.

2.7.2. Consequences: Entrapment can lead to injury or death if rescue is delayed or if the space collapses further.

2.8. Heat Stress:

2.8.1. Harm: Confined spaces can become extremely hot due to inadequate ventilation or exposure to heat sources.

2.8.2. Consequences: Workers can suffer from heat-related illnesses such as heat exhaustion or heat stroke, which can be life-threatening.

2.9. Psychological Stress:

2.9.1. Harm: The psychological stress of working in a confined space, especially when isolated or in low-light conditions, can lead to anxiety, panic attacks, or impaired decision-making.

2.9.2. Consequences: Impaired mental well-being can increase the risk of accidents, poor judgment, and decreased overall safety.

2.10. Inadequate Rescue Plans:

2.10.1. Harm: Failure to have a proper confined space rescue plan in place can result in delays in rescue efforts.

2.10.2. Consequences: Delays in rescuing an entrapped worker can lead to severe injury or death. Inadequate rescue equipment or training can exacerbate the situation.

3.0. Controls

3.1. Operatives must be physically fit to carry out confined space activities

3.2. Person experienced/ Trained in confined space activity to be assigned for the job.

3.3. MS&RA must be addressed to operative before entry.

3.4. A work permit must be taken, a pre-entry checklist to be completed and all precautions must be taken before entering.

3.5. Provide safe access and exit to and from the confined space as much as possible (Manhole size requirement –Min. 450 mm x 407 mm or 457mm Dia.)

3.6. Rescue procedure/system (Tripod with winch, Rescue Harness, etc.) in place, and sufficient trained persons are available for the rescue operation.

3.7. All persons in the confined space must wear safety harnesses for rescue purposes.

3.8. Access and all openings to be protected to prevent fall of materials/persons.

3.9. Carry out the atmospheric test and ensure there is a sufficient level of oxygen present in the area before entering.

3.10. Use forced air ventilation/ exhaust fan to remove toxic gases from confined space.

3.11. Shift working schedule as per condition to be made and strictly followed.

3.12. Oxygen percentage (19.5% to 23.5%)

3.13. Carry out atmospheric tests and ensure there are no flammable/ toxic gases present in the area before entry.

A. Flammable gas or vapors (Permissible Limit -<10% of LFL)

B. Carbon Monoxide (Permissible limit-<50 ppm)

C. Hydrogen sulfide (Permissible limit -<10ppm)

3.14. Do not keep any compressed/ flammable gas cylinders inside the confined space.

3.15. Provide adequate exhaust fans for proper ventilation.

3.16. Always use flameproof electrical equipment inside the confined space.

3.17. Use positive pressure breathing apparatus in a confined space.

3.18. The hot work permit must be taken before doing any hot work operation

3.19. Sufficient exhaust fan must be provided for ventilation.

3.20. Ensure there are no flammable gases/ vapors present in the confined space.

3.21. All operatives must wear the required PPE.

3.22. Sufficient lights (Flameproof) shall be provided in the confined space.

3.23. A proper communication facility (Walky-talky/ Radio) should be provided for confined space activities.

3.24. One full-time standby person with a communication facility shall be appointed outside the entrance.

3.25. Confined space registers are to be kept outside and strictly maintained.

3.26. Provide sufficient cool drinking water and oral rehydration fluids

3.27. Provide adequate ventilation and fans at the workplace.

3.28. Avoid working in a conditionshumid environment for a long time.

3.29. Shift system based on the humid condition to be strictly followed.

3.30. Close supervision and communication at all times

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