Under no circumstances should you combine VES with which type of ventilation operation?

Ventilation-Enter-Search (VES) is a tactical approach used in firefighting that combines ventilation techniques with search and rescue operations. When considering the application of VES, combining it with positive pressure ventilation can be particularly counterproductive.

Positive pressure ventilation involves using blowers to create a pressure differential that forces smoke and heat out of a structure. When VES is performed simultaneously with this method, the introduction of forced air can disrupt the conditions inside the building, potentially pushing smoke and fire towards areas where firefighters are operating. This can create hazardous conditions for both the victims being searched for and the firefighters conducting the operation. Effective evacuation methods and search tactics rely on understanding and reacting to the current conditions within a structure, and the use of positive pressure can adversely affect those conditions.

In contrast, other forms of ventilation like negative pressure, natural, and mechanical ventilation do not inherently create the same disruptive pressure dynamics when paired with VES. Therefore, understanding the interaction between ventilation methods and VES is crucial for safe and effective fireground operations.