While the new water heater design is in response to the ignition of flammable vapors by gas-fired water heaters, the issue is not whether gas-fired water heaters in homes and businesses throughout the U.S. are safe and reliable. They are not defective, nor do they present an unreasonable risk of injury. In many cases, the water heater is the most consistently performing appliance in the home.

The problem lies in consumers storing flammable liquids, such as gasoline, next to or near water heaters. The result, says the Consumer Product Safety Commission (CPSC), is flammable vapors - the byproduct of the evaporation of flammable liquids, such as gasoline, due to accidental spills or misuse - coming in contact with an ignition source and causing a fire or explosion.
CPSC says that traditionally designed gas water heaters, which draw combustion air through vents at the bottom of the appliance, have occasionally ignited these vapors. CPSC has associated nearly 2,000 fires a year, 17 deaths, and 316 injuries to flammable vapor fires and water heaters. However, it's important to note that only 5 percent of fires involving ignition of flammable vapors in homes were related to the gas water heaters. About 75 percent of the fires were due to spills of improperly stored gasoline or the improper use of gasoline.

To address the issue, a group of water heater manufacturers came together to form the Joint Research and Development Consortium. The goal was to develop a permanent, technical solution to the flammable vapor ignition resistance (FVIR) problem.

This ongoing, voluntary industry approach to developing FVIR technologies, says David R. Martin, vice president of Marketing for Rheem Water Heaters in Montgomery, AL, U.S., calls for manufacturers to invest their own resources in new product designs and the methods to test them. He says, "The new ANSI standard is a milestone because it represents an industry-leading approach that will ensure the long-term reliability of the new FVIR technologies."

Thus, as of June 30, all 30-, 40-, and 50-gal atmospherically vented water heaters will have to pass a flammable vapor test designed to keep water heater pilot lights and burners from igniting spilled gasoline. Phase 2 of the Standard begins July 1, 2004, with 30-, 40-, and 50-gal power-vented heaters, and Phase 3 covers the remaining models starting July 1, 2005. (Canada's Phase 1 will begin Jan. 1, 2004 - 6 months after the U.S. rollout).

The new design calls for a sealed combustion chamber with an air inlet, where air flows through the arrestor plate, which is a perforated piece of steel. If any flammable vapors enter the combustion chamber, the arrestor plate, or flame arrestor, controls the burning of the vapors and prevents the flames from escaping the unit into the room, thus avoiding a fire or explosion. A bench standard that calls for protection of the water heater from lint, dust, and oil, or LDO, was attached to the flammable vapor standard after it was determined in test studies that LDO contamination could be a problem.

According to Mr. Martin, the new FVIR standard will not affect the current installed base of residential gas-fired water heaters, or any unsold water heater made before the effective date.

However, says Mr. Martin, at this juncture, it is difficult to pinpoint how the industry-wide compliance with the ANSI standard will impact the residential water heater market this year. One observation he does make is that the new FVIR designs will cost more to produce and must necessarily be sold at significantly higher price points.
Design differences may be the largest difference, says Mr. Martin. Early in the development process, flammable vapor resistance was achieved with the use of arrestor technologies. As a result, all the new water heaters will incorporate some form of flame arrestor plate to shield the water heater burner and prevent its flame from spreading beyond the arrestor. "But while some type of arrestor will be common to every new FVIR unit, there still will be many design differences in the products that come to market after June 30, 2003," Mr. Martin says. "Over time, these critical variations may influence brand loyalties among plumbing and HVAC contractors."

One design difference within the flame arrestor plate is that the plate can pass the test necessary to meet the ANSI standard, but the standard does not cover a sustained flammable vapor incident. Meanwhile, says Mr. Martin, shutting off the gas supply, as all designs will do, does not stop combustion in the chamber. Thus, Rheem's new Guardian System calls for a complete shutoff of the combustion chamber when a flammable vapor incident is detected. The system is intentionally designed without a user interface or "reset" feature. As a result, says Mr. Martin, the homeowner is spared any concern with "nuisance" shutdowns or maintenance during the usual life of the product.

Despite warning labels that make it clear that consumers should never store gasoline near their water heater, and past aggressive programs to educate and warn consumers about the dangers of storing gasoline near their water heaters, such as the Gas Appliance Manufacturers Association's consumer awareness program in 1993, it's safe to assume that consumer responsibility will wane and accidents will happen.

What was once considered an unsolvable safety hazard has now been solved. And unlike past CPSC rulings and regulations, in this case, the water heater industry was given the opportunity to voluntarily develop the technology necessary to achieve a permanent solution. That's a refreshing change from the CPSC simply handing down regulation, as it has done in the past. The voluntary approach results in manufacturers taking control of their destiny and the products they manufacture.