Which mechanical device is needed to provide negative-pressure ventilation?

Which mechanical device is needed to provide negative-pressure ventilation?

• A. Flashlight
• B. Oxygen tank
• C. Smoke ejector
• D. Fan

Answer: (D)

Negative-pressure ventilation works by pulling air contaminated with smoke and heat out of a space, which lowers the pressure inside and causes air from outside to be drawn in through openings. The device that creates that exhaust and establishes the negative pressure is a fan. By placing a portable fan at an exterior opening and directing its flow outward, you remove smoky air from the room and pull in fresh air through other openings, improving visibility and temperature conditions for firefighters and anyone inside. A flashlight only provides light, an oxygen tank supplies breathing air to a person rather than ventilating the space, and a smoke ejector is a specialized tool that performs the same basic function of moving air to exhaust smoke, but the fundamental mechanism to achieve negative pressure is the fan.