Which gas is commonly used as the expellant gas in portable fire extinguishers?

Which gas is commonly used as the expellant gas in portable fire extinguishers?

• A. Asphyxiant
• B. Expellant Gas
• C. LDH
• D. Centrifugal Pump

Answer: (B)

The key idea is understanding the role of the gas that pushes the extinguishing agent out of the cylinder. In portable extinguishers, the expellant gas is a pressurized, inert gas that doesn’t react with the extinguishing agent or contaminate it, and its job is to drive the agent out smoothly and at a controlled rate. The term Expellant Gas directly describes this function, so it’s the best choice. In practice, nitrogen is a common choice for this pressurizing gas, though the exact gas can vary by extinguisher type. The other options don’t fit: an asphyxiant is a dangerous gas that reduces oxygen, the LDH refers to the extinguishing agent itself (loaded dry chemical), and a centrifugal pump is a mechanical device, not a gas.

The key idea is understanding the role of the gas that pushes the extinguishing agent out of the cylinder. In portable extinguishers, the expellant gas is a pressurized, inert gas that doesn’t react with the extinguishing agent or contaminate it, and its job is to drive the agent out smoothly and at a controlled rate. The term Expellant Gas directly describes this function, so it’s the best choice. In practice, nitrogen is a common choice for this pressurizing gas, though the exact gas can vary by extinguisher type. The other options don’t fit: an asphyxiant is a dangerous gas that reduces oxygen, the LDH refers to the extinguishing agent itself (loaded dry chemical), and a centrifugal pump is a mechanical device, not a gas.