Positive pressure tactics have the ability to move fire and fire gases (this is the ventilation part). This also can cause a rapid increase in fire development. Attempt to place the ventilation opening between your firefighters and the fire or between the fire and trapped victims.
What is a PPV fan?
The positive pressure (PPV) fan is the most commonly found fire service fan. It works by forcing air into a structure, creating a “higher pressure” inside the structure which forces the interior air to the “lower pressure” outside the structure through an exit portal.
What is positive pressure attack?
Positive Pressure Attack – The use of a high powered fan to control the flow of products of combustion, prior to fire control, with the intent of providing increased visibility and tenability for firefighters and potential occupants while fire suppression efforts are underway.
What is a disadvantage of hydraulic ventilation?
Hydraulic ventilation. When performing hydraulic ventilation, set the fog nozzle on a pattern. Wide enough to cover the exhaust opening. Which is a disadvantage of hydraulic ventilation? Firefighters operating nozzle must remain in heated, hazardous atmosphere throughout operations.
How does ventilation affect fire Behaviour?
We use fire ventilation to: … Facilitate the fire and rescue operation by reducing the thermal load, and to improve visibility in the building for the fire fighting crew. Prevent or contain the spread of fire or fire gases through a reduction of the impact of pressure and heat in the building.
What is negative pressure ventilation in firefighting?
Negative pressure ventilation is another method of ventilation sometimes used in firefighting efforts. The method of negative pressure ventilation is a process of using smoke ejectors to remove the smoke from a building. … The air that a fog stream draws in also draws out the smoke and ejects it outside.
What is tactical ventilation?
Tactical ventilation involves opening ventilation paths with the intent to make the fire behave or travel in a certain direction. This direction is meant to help maintain the life safety of both firefighters and civilians.
What is the difference between positive pressure attack and positive pressure ventilation?
Positive Pressure Attack (PPA) is a coordinated fire attack where fans are used to assist in controlling the fire. Positive Pressure Ventilation (PPV) is the use of fans to remove the products of combustion after fire control.
What is the drawback of negative pressure ventilator?
Disadvantages. NPVs do not work well if patient’s lung compliance is decreased, or their lung resistance is increased. They result in a greater vulnerability of the airway to aspiration such as inhalation of vomit or swallowed liquids, than with intermittent positive pressure ventilation.
Which is an example of vertical ventilation?
Vertical ventilation is the removal of super-heated toxic gases and smoke by allowing it to take its natural traveling path – UP! Fire companies make this possible by accessing the roof with a ladder, saws and other tools, and making an opening on the roof’s exterior, then punching the ceiling out with another tool.
Which is a disadvantage of positive pressure fans?
What is one disadvantage of positive-pressure fans? They can spread the fire if used improperly. … For heat and products of combustion to exhaust during positive-pressure ventilation, there must be an opening: near the seat of the fire.
What is the greatest risk to fire fighters performing vertical ventilation?
There are, of course, drawbacks to using vertical ventilation. As the officer, you are placing at least two firefighters in a dangerous spot to accomplish a needed task. There is the risk of structure or roof collapse, disorientation from heavy smoke conditions, and or stepping off the roof by accident.
What are three incident priorities when performing tactical ventilation?
Decisions on the emergency incident are reached as incident managers consider three main incident priorities: Life Safety (both the occupants and the responders), Incident Stabilization and Property Conservation.
How does a compartment fire affect pressure in and around gases in the compartment?
As the volume and temperature of the hot gas layer increases, so to does pressure. Higher pressure in this layer causes it to push down within the compartment and out through openings. The pressure of the cool gas layer is lower, resulting in inward movement of air from outside the compartment.
Why ventilation is very important during fire incident?
The basic premise of ventilation at a fire is to remove the products of combustion from the structure. This tactic has one main benefit, which is to protect the firefighters and officers inside the building trying to extinguish the fire because we let the fire, heat and smoke out of the building.
What disrupts the ventilation strategy and causes the fire to grow?
What disrupts the ventilation strategy and causes the fire to grow? … counter effects of natural ventilation.