Should Power Positive Ventilation fans be used in balloon-frame construction during the fire attack?

Using Power Positive Ventilation (PPV) fans in balloon-frame construction during a fire attack can be risky due to the inherent design of balloon-frame structures. In balloon-frame construction, the wall studs run continuously from the foundation to the roof, creating open channels that can allow fire to spread rapidly through walls and into attic spaces. When PPV fans are used, they can introduce a significant amount of air into a space that is already compromised by fire, potentially accelerating the fire spread.

In such structures, the use of PPV can create a phenomenon known as "flame propagation," where the introduced airflow can unintentionally push fire and smoke into hidden spaces, increasing the likelihood of fire migrating into the attic or adjacent rooms. This can complicate firefighting efforts and puts both firefighters and occupants at greater risk.

Hence, the decision to refrain from using Power Positive Ventilation fans in balloon-frame construction is based on the safety considerations associated with the unique fire dynamics present in these types of buildings. This precaution helps ensure that fire suppression activities remain controlled and effective.