Definition & Operational Usage of Positive Pressure Exhaust Ventilation
What Is Positive Pressure Exhaust Ventilation?
Functioning by placing exhaust fans inside the hazardous environment facing outward, this technique mechanically draws smoke and toxic gases out of a compartment.
⚠️ Operational Safety Warning:Fans placed in the flow path must be intrinsically safe to prevent igniting combustible gases.
Why Positive Pressure Exhaust Ventilation Matters on the Fireground
Effectively clears lingering contaminants during overhaul when traditional positive pressure from the outside is not feasible.
Relevant NFPA Standards
- NFPA 1010: Standard on Professional Qualifications for Firefighters
- NFPA 1550: Standard for Emergency Responder Health and Safety
Field Procedures & Tactical Steps
- Identify the most direct exhaust portal.
- Deploy an intrinsically safe ejector fan inside, facing out.
- Seal the space around the fan using salvage covers to prevent churning.
- Open a clean-air inlet on the opposite side.
- Monitor interior CO levels as smoke clears.
Common Context & Application
Basement fires or deep commercial structures with limited airflow paths.
Frequently Asked Questions about Positive Pressure Exhaust Ventilation
How is this different from PPV?
It pulls air out (negative pressure inside) rather than pushing it in.
What is churning?
Air recirculating around the fan instead of exhausting.
Other Names for Positive Pressure Exhaust Ventilation
PPEVPositive Pressure Exhaust
Positive Pressure Exhaust Ventilation may also appear in training materials, NFPA standards, or department SOPs as: PPEV, Positive Pressure Exhaust.
Relevant Tools
Operational calculators related to Positive Pressure Exhaust Ventilation:
Category:Fireground Operations
— Core tactics, command, suppression, ventilation, search, and water supply terminology used on the fireground.