The benefit of using a flammable vapor resistant ignition water heater is that it reduces the likelihood of flames igniting by the water heater from gasoline vapors or other sources. These water heaters must meet requirements created by the American National Standards Institute in July 2003.
FVIR water heaters automatically shut down when a certain temperature is reached, through a thermal release device. Other names for the feature include a thermal sensor, thermal cutoff switch or a high-temperature limit switch. The machines also have a screen or plate on the bottom that prevents flames from coming out in the event of a fire. Certain machines have removable screens that allow the user to wash them, and screens may be made from stainless steel or ceramic. If too much lint accumulates on the screen, it can prevent combustion air from entering and keep the burner from igniting.
Since being introduced in 2003, FVIR water heaters were launched in three phases which ended in July 2005. As of February 2015, the FVIR guidelines apply to water heaters with 30-, 40- or 50-gallon tanks and up to 75,000 British thermal units per hour. The feature is standard in all water heaters manufactured since then.