Which device is designed to prevent flame flashback in oxy-fuel systems?

• A. Flame screen
• B. Two-way check valve
• C. Flashback arrestor
• D. Three-way check valve

Answer: (C)

When working with oxy-fuel systems, the device that stops a flame from traveling back into the gas supply is a flashback arrestor. Its job is to prevent a flame that starts at the torch from reaching regulators or cylinders by blocking reverse flow and quenching the flame. It typically contains a heat‑activated element that closes off the passage when exposed to high temperatures, sometimes aided by a one-way valve and a flame‑arresting screen to cool and dampen the flame front. This combination is specifically designed to halt flashbacks, which is why it’s the best choice for this purpose. A flame screen alone protects the burner tip but doesn’t stop backflow into the supply lines. Check valves that are merely two‑way or three‑way manage general flow direction and aren’t equipped to respond to flame temperature and shut off the pathway in a flashback.