Confined Space Ventilation

Overview

Confined Space Ventilation should be managed through a planned system of work: identify the task-specific hazards, eliminate exposure where practical, use engineered or collective controls before relying on PPE, verify critical safeguards before starting, and stop the task when controls are missing or conditions change. This guide applies those principles specifically to using mechanical ventilation to control atmospheric hazards during confined-space work.

Main Hazards

• • Dead zones where fresh air does not reach
• • Recirculation of exhaust or introduction of contaminated air
• • Oxygen deficiency or enrichment
• • Toxic or flammable atmosphere
• • Engulfment, entrapment or difficult rescue

Essential Controls

1. 1Position supply and exhaust to move fresh air through the actual breathing and work zones.
2. 2Keep ventilation operating as required and verify effectiveness with atmospheric monitoring.
3. 3Identify permit-space hazards and isolate connected energy, process and material sources.
4. 4Test the atmosphere with suitable calibrated instruments before and during entry as required.
5. 5Provide ventilation, communication, attendant coverage and controlled entry authorization.
6. 6Prepare non-entry or entry rescue arrangements appropriate to the space and hazards.

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