816 Confined Space Safety in Construction

Permit Space Evaluation Procedures

The employer must use the following procedures to evaluate permit space conditions whenever entry operations are conducted.

Test conditions in the permit space to determine if acceptable entry conditions exist before changes to the space's natural ventilation are made, and before entry is authorized to begin.

If the employer proves that isolation of the space is infeasible because the space is large or is part of a continuous system (such as a sewer), the employer must:

• Perform pre-entry testing to the extent feasible before entry is authorized; and,
• If entry is authorized, continuously monitor entry conditions in the areas where authorized entrants are working.
• If the employer can prove that equipment for continuously monitoring that hazard is not commercially available, periodic monitoring of the permit space atmosphere may be used in accordance with 1926.1204(e)(2);
• Provide an early-warning system that continuously monitors for non-isolated engulfment hazards. The system must alert authorized entrants and attendants in sufficient time for the authorized entrants to safely exit the space.
• Continuously monitor atmospheric hazards unless it can be proved that the equipment for continuously monitoring a hazard is not commercially available or that periodic monitoring is of sufficient frequency to ensure that the atmospheric hazard is being controlled at safe levels. If used, periodic monitoring frequency enough to ensure acceptable entry conditions are being maintained during the course of entry operations.

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