Manhole Entry Safety: Atmosphere, Flow & Rescue

• Oxygen deficiency or hazardous atmosphere
• Toxic or flammable gases
• Falls through open manholes or during entry
• Traffic exposure around the work area
• Water, flow, or sudden flooding
• Poor rescue planning for confined space emergencies

Manhole entry safety starts with recognizing hazards that may not be visible from the surface. Sewer, stormwater, utility, and communication structures can contain hazardous atmospheres, water or flow hazards, restricted access, falls, traffic exposure, and conditions that make emergency rescue difficult.

Before anyone enters, workers should determine what confined space procedures apply to the manhole and the work being performed. Atmospheric testing, permits, attendants, ventilation, communication, entry equipment, and rescue planning may be required depending on the space and its hazards.

The atmosphere should never be assumed safe because there is no unusual odor or visible problem. Oxygen deficiency, toxic gases, flammable gases or vapors, and changing atmospheric conditions can create serious entry hazards.

Ventilation may be needed before or during entry when atmospheric hazards are present or could develop. Opening the manhole cover alone should not be treated as proof that the atmosphere is safe.

Water and flow conditions should be evaluated before entry and monitored during the work. Rainfall, upstream discharge, pumps, valves, blocked lines, or changing system conditions can introduce water or create sudden flow hazards.

Entry and exit equipment should be appropriate for the space and inspected before use. Ladders, steps, harnesses, retrieval systems, tripods, and other access equipment should not create additional fall or entanglement hazards.

Traffic and pedestrians must also be controlled around the opening. Barriers, cones, positioning, or other traffic-control measures may be needed to protect entrants and workers at the surface from vehicles and falls.

Safe manhole entry means evaluating the space before entry, testing and controlling atmospheric hazards, managing water and flow, maintaining safe access and communication, and having appropriate rescue arrangements ready before work begins.

• Evaluate confined space requirements before entry.
• Test the atmosphere before and during entry when required.
• Ventilate the space when needed.
• Use proper traffic control around open manholes.
• Protect openings from pedestrians and vehicles.
• Inspect access and retrieval equipment.
• Do not enter until required rescue arrangements are in place.

• Does this manhole require confined space entry procedures?
• Has the atmosphere been tested?
• Is ventilation needed before or during entry?
• Is traffic control adequate around the open manhole?
• What is the rescue plan if something goes wrong?