At least _______ fusible link or heat detector shall be installed within each exhaust duct opening in accordance with the manufacturer's listing.

At least _______ fusible link or heat detector shall be installed within each exhaust duct opening in accordance with the manufacturer's listing.

• A. Two
• B. Three
• C. Five
• D. One

Answer: (D)

In NFPA 96, protecting the exhaust duct openings relies on heat-detection devices or fusible links placed at those openings so the system can respond quickly to a fire in the duct. The minimum requirement is one fusible link or heat detector installed within each exhaust duct opening, and it must be installed in accordance with the device’s listing. This ensures there is a reliable point of activation for shutoff or suppression when heat is detected. The other numbers aren’t the standard minimum: while more devices could be used if the listing or the duct design calls for it, the code specifies at least one per opening. So the best answer is one.

In NFPA 96, protecting the exhaust duct openings relies on heat-detection devices or fusible links placed at those openings so the system can respond quickly to a fire in the duct. The minimum requirement is one fusible link or heat detector installed within each exhaust duct opening, and it must be installed in accordance with the device’s listing. This ensures there is a reliable point of activation for shutoff or suppression when heat is detected.

The other numbers aren’t the standard minimum: while more devices could be used if the listing or the duct design calls for it, the code specifies at least one per opening. So the best answer is one.