If fire is close to exposure, which ventilation technique might be contraindicated?

When fire is close to an exposure, horizontal ventilation is often contraindicated due to the potential for spreading the fire. This method involves directing smoke and heat laterally from a building, which can inadvertently push flames and hot gases towards the exposure, increasing the risk of fire extension and compromising safety. This is particularly concerning in suburban environments where buildings may be in close proximity to one another and where the risk of ignition for adjacent structures is heightened.

In contrast, vertical ventilation aims to release heat and smoke directly upward, effectively reducing the concentration of heat in the lower levels where firefighters operate, and can help protect exposures by reducing the likelihood of embers or flames traveling horizontally. Natural ventilation utilizes existing openings in the structure to allow heat and smoke to escape, which can also be beneficial, while mechanical ventilation uses fans to remove smoke but does not inherently direct flames towards an exposure like horizontal ventilation can. Understanding these dynamics helps develop an effective response strategy to minimize risk and manage fire spread effectively.