In water heater tanks with FVIR systems, what component prevents flames from traveling backward?

In water heater tanks equipped with Flame Venting ignition Resistant (FVIR) systems, the component specifically designed to prevent flames from traveling backward into the tank is the flame arrestor plate. This device acts as a barrier to extinguish any flames or hot gases that might attempt to move back into the tank through the venting system. The flames are typically cooled as they pass through the arrestor's mesh or perforated design, thereby ensuring that any ignition does not ignite gases inside the tank.

Understanding the role of the flame arrestor plate is essential for ensuring safety in gas-fired water heaters. It is a critical feature that protects the integrity of the tank and reduces the risk of catastrophic events, such as explosions or fire hazards that could arise from backdraft flames. In contrast, other components like heat shields and insulation barriers serve different protective functions, such as improving energy efficiency or directing heat, but they do not specifically prevent flame migration in the same way the flame arrestor plate does. The safety valve, while important for pressure relief, also does not play a role in flame arresting.

Therefore, the flame arrestor plate is the key component for ensuring safe operation of FVIR systems in water heaters, making it the correct answer to identify in this