Environmental, Health and Safety Services

Confined Space Procedures - Forced Air Ventilation

This procedure may only be used if an actual or potential atmospheric hazard is the only hazard within the space.

General Requirements

Ventilation

The forced air will be directed to the immediate vicinity of each employee within the confined space. Ventilation must be provided until all employees exit the space.

The method and ventilation equipment selected will be determined based upon the size of the confined space, the size of the entrance into the space, the gases present within the space, and the source of make-up air.

If mechanical ventilation should fail during entry operations, all employees must immediately evacuate the space until ventilation is restored and retesting indicates acceptable entry conditions.

Ventilation systems and electrical tools and equipment used in flammable atmospheres must be explosion-proof and appropriately rated for the hazard.

There may be no hazardous atmosphere within the space whenever any employee is inside of the space.

If a hazardous atmosphere is detected during entry:

  • Each employee must leave the space immediately;
  • The space must be evaluated to determine how the hazardous atmosphere developed; and,
  • Measures must be implemented to protect employees from the hazardous atmosphere before any subsequent entry takes place.

Entry Procedure

    1. The departmental confined space supervisor must complete the back side of the Assessment Form ( doc | pdf ) prior to personnel entering the confined space.
    2. Establish forced air ventilation to employee work area within the confined space.
    3. Establish personal protective equipment and procedural requirements for entry.
    4. Establish and maintain communication between entrants and personnel outside the confined space. Notify appropriate departmental personnel when entry begins and after all personnel have exited the confined space.
    5. Make the initial evaluation information available to each entering employee prior to entry.
    6. Continuous atmospheric testing must be performed. Results must be documented on the Assessment Form ( doc | pdf ) every hour.
    7. Close out project on Assessment Form ( doc | pdf ) when work is completed. Submit back copy of form to EHSS.