Aeration, Clearance, and Re-Entry Procedures
Aeration, Clearance, and Re-Entry Procedures
This domain tests how you remove fumigant safely and prove that the structure is fit for re-entry. Aeration is not simply opening doors; it is a monitored process with documented readings, controlled access, and a clearance decision made by the certified applicator.
Aeration sequence
- Keep warning signs and access control in place until clearance is complete.
- Open the structure as the label and plan direct; remove tarps and seals to allow ventilation.
- Use fans and mechanical ventilation where allowed; ventilate low areas, closets, attics, and crawlspaces.
- Monitor with a calibrated gas detector at multiple points, including low areas and closed spaces.
- Compare readings to the label and rule clearance level; do not average readings or clear from a single room.
- Record aeration start and end, readings by location, instrument calibration, and the applicator's clearance decision.
- Only then remove signs and allow occupants to re-enter.
Worked example
After aeration, a detector reads 8 ppm in the living room and 3 ppm in the attic for sulfuryl fluoride. The label clearance level is 5 ppm. Reasoning: the living room fails, so the structure is not clear even though the attic passes. Continue ventilation and re-test the living room and any connected low areas until every reading is at or below 5 ppm. Do not average 8 and 3 and call it 5.5; that would be wrong and unsafe.
Traps
- Relying on elapsed time instead of instrument readings.
- Clearing after one reading in one room.
- Using an uncalibrated or wrong detector.
- Removing warning signs before clearance.
- Allowing occupants to re-enter while aeration is still underway.
Key points
- Aeration is monitored, not time-based alone.
- Test multiple locations, especially low and closed spaces.
- Every reading must meet the label clearance level.
- Record calibration and readings by location.
- Re-entry is allowed only after the certified applicator clears the structure.