What device minimizes the passage of air-borne sparks or embers into a plenum, duct, or flue?

Study for the NFPA 96/17A Class K Test. Prepare with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

The main idea is preventing ignition sources from traveling into ventilation paths. A spark arrester is installed at exhaust outlets and within ducts to capture or block air-borne sparks and embers before they enter the plenum, duct, or flue. It usually uses a metal screen or mesh that allows hot gases to pass but traps larger particles, reducing the chance that a spark could ignite grease, dust, or other combustibles inside the ductwork. This protection is especially important in grease-laden exhaust systems where a small ember could start a duct fire.

The other options don’t serve this barrier function. A dampener controls how much air moves through the system, not what kind of particles pass through. A smoke detector senses smoke presence to trigger an alarm or suppression actions, but it doesn’t stop sparks from entering the duct. A vent is simply an opening for air flow and does not impede the passage of sparks or embers.