The entire U.S. water heater industry is gearing up for the most extensive product-design change since Edwin Ruud invented the storage tank-type water heater more than a century ago. This design change will incorporate a revolutionary new technology — flammable vapor ignition resistance (FVIR) — that will effectively counter the problems caused by improper storage or use of gasoline and other flammable liquids near gas-fired water heaters in the home.
Effective July 1, 2003, residential gas-fired water heaters with storage capacities of 30, 40, or 50 gallons must meet a new American National Standards Institute (ANSI) standard, ANSI Z21.10.1-2001. In a nutshell, any conventional, atmospheric-type water heater with a storage capacity of 50 gallons or less that is produced on or after the effective date must be designed so it cannot ignite flammable vapors caused by spilled gasoline outside the unit. The new ANSI FVIR standard will not affect the current installed base of residential gas-fired water heaters, nor any unsold water heaters manufactured prior to July 1, 2003, regardless of size or Btuh input. The standard applies to both natural gas and liquid propane units.