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Kaplan ITA's Monthly Inspection Tips - Free Electronic Newsletter

April, 2004
FVIR Water Heaters
Issue #24

Dear Inspector,

This month we have a guest inspection tip author, Don Norman, Managing Instructor of Kaplan Illinois.

I'd like to talk to you about Flammable Vapor Ignition Resistant Water Heaters or FVIR water heaters. The Water Heater Joint Research and Development Consortium (WHJRDC) have developed new water heater technology that solves the problem of flammable vapor ignition associated with gas water heaters. The new water heaters meet the ANSI Z21.1.1-2001 standard that states the water heater "shall not ignite flammable vapors outside the water heater created by the spilling of…gasoline onto the floor". A study by the Consumer Products Safety Commission (CPSC) was able to identify almost 2000 fires as a result of water heaters resulting in 17 deaths and 316 injuries through 1994. About 75% of these fires were related to improper storage or handling/spillage of gasoline.

With compliance to FVIR standards, new complying water heaters will no longer have to be elevated in garages and similar locations unless required by the manufacturer or local code authorities. Some codes have already been updated to reflect the FVIR technology, the 2002 National Fuel Gas Code and the 2003 International Fuel Gas Code being two.

The new water heaters incorporate new technology that helps accomplish the requirements of the new ANSI Standard. This technology consists of:

  • A device to prevent ignited vapors from passing out of the combustion chamber
  • A one way intake system to control the movement of makeup air into the combustion chamber
  • An inner door and burner assembly to create a sealed junction with the combustion chamber, preventing combustion air and flammable vapors from entering the chamber through the front of the water heater

While all manufacturers differ slightly in design and how to accomplish the desired outcome, they all have the following FVIR features in common:

  • Flame arrestor plate. Located under the burner, this plate is designed to allow combustion air into the combustion chamber but keep flames from escaping downward and igniting flammable vapors below. This plate is a key element of the FIVR technology and might also be called an arrestor plate or a flame arrestor.
  • Thermal cutoff. This is a switch designed to shut the unit down if it senses excessive temperatures caused by inadequate combustion air inside the combustion chamber. Inadequate combustion air can be caused by ignition of flammable vapors, inadequate venting, inadequate makeup air or the accumulation of lint, dust or oil on the LDO screens.
  • Lint, dust or oil (LDO) screens. This screen is to protect the combustion process from lint, dust or oil. This screen was added after it was determined that LDO contamination could adversely affect the system. The openings in the screens are subject to dirt accumulation especially in basements and utility areas. As part of the FVIR certification process, water heaters must shut down before exceeding carbon monoxide (CO) limits.

The FVIR water heater phase-in began in July, 2003 and will continue for the next several years. Existing inventories of conventional water heaters may be used until inventory is exhausted. Implementation of the phase in will be in 3 stages. PHASE 1: July 1, 2003: 30, 40 and 50-gallon atmospheric vent models. Manufactured housing models are excluded. PHASE II: July 1, 2004 30, 40 and 50-gallon power vented models. Manufactured housing models are excluded. PHASE III: July 1, 2005 All other gas-fired models with inputs of 75,000 BTU or less.

For more information check out http://www.gamanet.org/consumer/fvir/
and http://www.reevesjournal.com/CDA/ArticleInformation/RetrospectiveItem/0,3852,90680,00.html
or any manufacturer Web site. Some of the larger water heater manufacturers are State and Rheem.

You also could inform your clients that the cost of the new FVIR water heaters will be increasing 50 - 60 percent from the standard models we now see.

Check out ITA's Newest Home Inspection Educational Supplies and Home Inspection Tools

Be careful out there!

Don Norman
Kaplan Professional Schools
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