When should a hood exhaust fan cease operation following the activation of an extinguishing operation system?

The correct understanding of when a hood exhaust fan should cease operation after the activation of an extinguishing system is based on the guidelines set forth by the NFPA 96 standard. According to the standard, the exhaust fan should stop only if required by a listed component. This means that the specific design and safety features of the installed system would dictate whether the fan should cease operation immediately, after some time, or continue to run.

Certain fire suppression systems may require the exhaust fan to remain operational to help remove smoke and other byproducts of combustion while the fire is being controlled. Conversely, others may specify that the fan must stop to avoid fanning the flames or distributing smoke. Therefore, it is crucial to adhere to the requirements of the listed components that are part of the installed system, as they provide the necessary directives based on safety testing and manufacturer recommendations.