Negative pressure ventilation (NPV)
NPV is used in a variety of situations, primarily where conditions and location do not favor natural ventilation or positive-pressure ventilation.
This involves lowering the pressure inside the volume. The fan is placed inside the smoke-filled area and blows the smoke to the exterior. Simultaneously the crew create a fresh air inlet opening on the opposite side. A continuous stream of air then evacuates all smoke.
NPV is used in a variety of situations, primarily where conditions and location do not favor natural ventilation or positive-pressure ventilation. This method is particularly effective on fires in covered parking lots, underground tunnels/stations, basements, and cellars.
The ParkFan 80 was designed as an efficient, easy-to-implement solution for smoke removal from covered parking lots.
In their combination of performance and maneuverability, these fans remain unequalled.
A single crewmember can easily deploy 1 or 2 ParkFans inside the smoke-filled volume and direct the airstream and smoke out of the premises.
Accessories such as extraction ducts or suction/blow kits convert fans designed for PPV into extractors of smoke from confined spaces (cellars, basements etc.) or large volumes such as parking lots by using the Easy 4000 LFV fan and its extraction ducts.