Positive Pressure Ventilation or PPV is an innovative ventilation technique developed by firefighters to control heat and smoke during fires. Much more effective than traditional air circulators, PV has proven effective in controlling airborne contaminants, replacing interior air, removing heat, and supplementing fixed ventilation systems. By pressurizing properly and controlling the resultant flow path, these changes will occur very rapidly. This is accomplished by using specialized blowers with the power and velocity to pressurize the interior of a structure or building. Although each site has its own peculiar requirements, the underlying flow control principles are universal.