All FVIR water tanks share which common component?

Flame-arrestor plates are a critical safety feature in FVIR (Flame Venting Instantaneous Recovery) water heaters. These devices are specifically designed to prevent flames from escaping the combustion chamber of the water heater and igniting flammable vapors that may be present in the surrounding area. The flame-arrestor plate functions by allowing combustion gases to escape while trapping any flames within the unit. This design is essential for mitigating fire hazards, which is particularly important in residential settings where water heaters are commonly located in garages or basements where flammable materials may be present.

While temperature gauges, pressure relief valves, and copper piping are also found in many water heaters, they do not serve the same purpose in preventing fire hazards. The temperature gauge monitors the water temperature, the pressure relief valve ensures safe operation by releasing excess pressure, and copper piping is used for water supply and distribution. However, these components do not directly contribute to the flame-safety aspect that is the hallmark of FVIR water heaters. Hence, the flame-arrestor plate is the defining feature that is universally present in all FVIR water tanks.