Gravity open vents are made of plastic that soften from heat of a fire and fall down. This statement is:

Gravity open vents are made of plastic that soften from heat of a fire and fall down. This statement is:

• A. False
• B. True
• C. The vents are metal and do not soften
• D. The vents are glass and shatter

Answer: (B)

Gravity-open vents are passive devices that rely on gravity to operate, and many designs use plastic components for lightweight, low-cost construction. Plastics soften at elevated temperatures well before metal would, so in a fire the vent parts can lose stiffness, deform, and sag or drop downward. That collapse or falling action can seal or obstruct the opening, which is a known failure mode for plastic gravity-open vents. Because of this heat-sensitive behavior, the statement is true. Metals or glass would not exhibit the same softening/falling behavior under fire conditions, which is why those materials would not match the described scenario.

Gravity-open vents are passive devices that rely on gravity to operate, and many designs use plastic components for lightweight, low-cost construction. Plastics soften at elevated temperatures well before metal would, so in a fire the vent parts can lose stiffness, deform, and sag or drop downward. That collapse or falling action can seal or obstruct the opening, which is a known failure mode for plastic gravity-open vents. Because of this heat-sensitive behavior, the statement is true. Metals or glass would not exhibit the same softening/falling behavior under fire conditions, which is why those materials would not match the described scenario.