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.
Be careful out there!
Don
Norman
Kaplan Professional Schools
Now You're Ready For Business!