Confined Space Sewer EntryReference Guide (OSHA)

What are confined spaces?Confined spaces are spaces that:

Are large enough and so configured that an employee can bodily enter and perform assigned tasks in the space.

Have limited or restricted means for entry and exit. Are not designed for continuous occupancy by

employees.

When preparing to enter an active sewer, what safe work practices must be followed?

Before entering any sewer, determine if the sewer is a permit-required sewer based on the presence of: A hazardous atmosphere. An engulfing hazard. A hazardous internal configuration. Other recognized serious safety or health hazards.

Calibrate testing equipment. Without entering the confined space, test the

atmosphere to ensure it is within the following acceptable limits: Oxygen Content 19.5% - 23% Lower Explosive Limit <10% Carbon Monoxide <25ppm Hydrogen Sulfide <10ppm Heat (if applicable)

If a hazardous atmosphere is detected – Implement an effective ventilation plan, using forced

ventilation. Open additional covers, man-ways and manholes to

increase air circulation when possible. Retest atmosphere to verify ventilation

effectiveness, without entering the confined space. Successful elimination of hazardous atmosphere

results when all acceptable limits are met. Document all test results on the “Permit-Required

Confined Space Sewer Entry” form.

Before entering the sewer, complete the following:

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Document all hazard evaluation/monitoring and/or hazard elimination on the form – “Permit-Required Confined Space Sewer Entry.”

Reclassify the sewer to non-permit-required status (insert the word “Non” on the form) in the documented absence or documented elimination of all hazards.

Post completed permits at the confined space entrance. Terminate all permits upon completion of the work and entry operations.

Identify and perform required lockout/tagout on all energy sources (pumps).

Isolate piping by use of blanks, use of double block and bleed procedures, disconnection and misalignment of lines and/or closure of valves and use of lockouts.

Clean manholes by washing, neutralizing and purging to eliminate harmful/toxic/flammable materials, gases, or vapors. (Monitor atmosphere and use ventilation if required.)

Prepare for access and entry by providing railings, temporary covers or temporary barriers around the entrance; securing all ladders; eliminating all tripping hazards; and locating all pumps, generators, ventilation systems and compressors with internal combustion engines a safe distance from the confined space.

Enter the sewer only upon authorization by completed and signed “Permit-Required Confined Space Sewer Entry” form or “Non-Permit-Required Confined Space Sewer Entry” form.

When entering the active sewer, what safe work practices must be followed?

Wear all required personal protective equipment, including respirators.

Wear safety harnesses and lines as required. A second person with the capability to communicate with the entrant shall tend the lifeline from the time of entry until the time of exit.

Maintain rescue plans in effect during permit-required confined space entry.

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Ensure emergency rescue equipment is available on-site and attended when in use.

Maintain proper ventilation and a contaminant-free air supply by – Using mechanical ventilation systems to provide

100% outside air. Opening additional covers, man-ways and manholes

to increase air circulation. Using portable blowers to exhaust fumes, vapors

and mists from welding, painting, sealing, chipping, etc.

Retest the atmosphere upon entry. Continuously monitor the atmosphere while performing work in the confined space. Evacuate the space immediately if the monitor alarm sounds, unless appropriate respiratory protection and PPE are being used.

Use electrical equipment, portable cords and tools that are explosion proof and protected by GFCIs.

Use non-sparking tools in areas that have the potential to contain flammable vapors and gases.

Obtain a “Hot Works” permit and use failsafe methods to eliminate the possibility of explosion when welding or cutting on vessels that have contained flammable or combustible materials.

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