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pdfOMB Control Number 3041-0029
INVESTIGATION GUIDEILINE
Revised September 22, 1994
RANGE
(Excludes
Counter-top
AND
OVEN
FIRES
Units and Solid-Fuel
Fired Products)
Complete Attachment A for all fires. If fire resulted from cookingrelated activity, also fill out Attachment B. Attach to CPSC Form
182, Epidemiologic Investigation Report, along with copy of Fire
Incident Report.
I.
INTRODUCTION
A.
Background
Information
Based on data from the National Fire Incident Reporting System (NFIRS) and
the National Fire Protection Association, ranges/ovens were involved in the
following estimated residential fire losses in 1991:
93,100 fires
240 deaths
4,780 injuries
$394.6 million in property loss
Available data indicate that unattended cooking fires are a major cause of
range/oven fires. Other causes include failure of a variety of component
parts or features related to installation. It is believed that existing
technology is capable of reducing the fire hazard related to cooking
activities.
The purpose of these investigations is to provide details of the incidents to
help focus technical changes to these products to reduce the number of
fires, deaths and injuries.
Page
1 of
31
6.
Product
Description
Definitions
and General
Description
-
Products
include any free-standing
range (that is, a combination
range/oven),
or a built-in and/or wall oven, or an installed cooking surface,
Plug-in and portable counter-top
units are not
except wood/coal-fired.
and hot plates.
Fires in
included; e.g., ovens, toaster ovens, microwaves,
exhaust hoods are included only if an integral part of the range.
-
Note
product
information
and illustrations
in Attachment
C.
C. Specific Items of Interest
If the incident involved cooking activities,
we are particularly
interested
in
learning the details, e.g., what was being cooked, over what time period,
(Fill out Data Record Sheet;Attachment
B in addition to
and heat setting.
Attachment
A.)
If the incident involved apparent arcing, gas leak, or other failure of a
component,
provide photographs
and a description
of the failure point.
Contact consumer immediately
to request that any failed components
not be
discarded,
e.g., gas valve, igniter, pilot burner, main burner, flexible
connector,
and heating element control.
Describe any previous problems with range;
malfunctions,
or difficulties
with use.
Include
diagrams
of controls
Please note that this
relevant information
investigation
should
has been anticipated
and settings
e.g.,
repairs,
perceived
if available.
is a guideline,
not a check list. Any
discovered
in the course of the
be included regardless of whether
it
here.
Page
2
of
31
INVESTIGA’l!ION GUIDELINE
D. Headquarters
Contacts
Extension 1275
Linda Smith, Project Manager, EPHA -- (301) 504-0470,
William Rowe, EPHA -- (301) 5040470,
Extension 1271
(301)
504-0608,
Extension 1356, Gas
Lawrence Hershman, EXCE -Ronald Jordan, ES--(301) 504-0508,
Extension 1295, Gas
Extension 1310, Electric
Mai Ngo, ESEE -- (301) 504-0494,
Renae Rauchschwalbe, EXCE -- (301) 504-0608,
Extension 1362, Electric
II. INSTRUCTIONS FOR COLLECTING SPECIFIC INFORMATION
(Data Record Sheets are attachments.)
A.
Synopsis
.
Describe the sequence of events that led to the incident. Describe the
incident including component failure or multiple failures (if known),
subsequent events, including contributing factors as appropriate, and details
of injuries.
For data retrieval from the computer, please make sure the
following key words are used in the synopsis as appropriate:
Cooking fire, surface element (halogen, radiant, solid,
conventional coil), bake elements, broil elements, plug,
thermostat, receptacle, electric, gas, gas lead, pilot light,
igniter, valve, gas control, flexible connector, pressure regulator,
gas regulator, explosion, LP-gas or natural gas.
B. Description of Incident Environment
Pre-Incident:
Include in this portion of the narrative a description of the unit
as installed, subsequent modifications (e.g., converted from LP-gas to natural
gas), and specific circumstances leading to the incident as follows:
l
- Describe product location, indicating cleanliness or neatness of use area,
and specifying items on adjacent counter-tops.
Describe any items that
were stored on or in the appliance.
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lNVESIlGATION
GUID-
Determine
if and where aluminum foil was used to
oven floor, under heating elements (electric)/surface
spills; e.g.,
burners (gas).
Measure clearance between
surface heating units and combustible
above and to the sides.
Indicate if wood cabinets.
Describe
details
of range
connection
to power
in
catch
items
or fuel supply.
Specify if the unit was wired directly into the circuit
armored cable or a cord and plug-in connection.
with
List the size, type, and manufacturer
of the overcurrent
(fuse or circuit breaker) and determine
whether device
off current during the incident.
conduit
or flexible
protection
functioned
device
to shut
Incident:
Describe in the narrative how the fire and any explosion happened.
State relevant facts and’ the source of any technical evaluations.
If the
incident involved apparent arcing, gas leak or other component
or
installation-related
failure, describe and photograph
in detail.
Determine
if there was an explosion or fire involving a gas leak and try to
specify the exact place where gas was escaping.
Photograph
relevant
component
parts, if possible, paying particular attention
to the area
between
the tank or gas line entrance,
the flexible connector
or rigid gas
If LP gas, determine
when tank was last filled, and
pipe, and the appliance.
any intervening
usage or sequence of events related to the incident.
Determine
if the regulator was frozen due to exposure to sleet or freezing
rain, over pressure on line, any problems with gas supply, e.g., turning on
burners.
Also make initial contact with the respondent
as soon as possible
to request that the gas valve, igniter, pilot burner, and main burner not be
Information of particular importance is: a) date of manudiscarded.
facture, b) year of purchase, c) location of gas leak, d) description of part
failure, e) identification of connector and coating materials, f) role of
movement of the connector, and g) presence of an ammonia atmosphere.
Determine
how produEt was being used at the time of the fire (e.g., for
cooking activities,
for heating home, or left on inadvertently).
If product
was being used for cooking, provide details of cooking activity as requested
on Attachment
6 along with any other relevant information.
Page
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of
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INVESIXGATION
GUIDELINE
If the fire started from cooking related activities, specify if the user left the
appliance unattended and for how long; the condition of the appliance
(e.g.,soiled from food spillage, clean surface, etc.); temperature setting
(e.g., high, medium); who discovered the fire and at what time; what was
being cooked and amount (e.g., four pieces of chicken in eight ounces of
corn oil); how it was being cooked and time period; and the size, type,
material and condition of pan (e.g., old and encrusted from food spillage,
clean pan, etc.); whether or not a family member was present just prior to
the fire and whether a power outage was involved.
If the fire appeared to involve the range or oven connections to the branch
circuit, provide as many details of the wiring and connection involved as
possible. Provide voltage, wire gauge, material of conductor and sheathing
(copy any markings available), and details of connection method including
grounding. Problems related to the use of aluminum conductors or damage
to power supply cords are of particular interest. Photograph connections
as appropriate to show failure point (e.g., terminal block or pigtail plug and
socket).
Describe any attempts to put out the fire (e.g., cover pan, use
extinguisher, etc.)
Post-incident:
-
Describe conditions that may have contributed to fire ignition or spread
(e.g., crowded or cluttered room, children playing, etc.).
Specify if the unit was repaired or replaced after the incident. Talk to the
repairman and gas company to determine cause of any component failure.
Specify estimated property damage, if any, including fire spread and dollar
loss.
Indicate if a detector (smoke, heat, or CO) was in dwelling, its location,
and whether it operated. If powered, but it did not operate even though
fire was big enough that it should have operated, indicate whether it was
battery operated or permanently wired, manufacturer, and model number.
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1
INVESTIGATION
GUIDELINE
C. Description of Injured Person(s) and Product interaction
(Victim/Product Environment Interface)
- Describe accident scenario including all injuries and/or deaths sustained;
indicate if hospitalized, for how long, treatment, and prognosis.
- Indicate user’s age, sex, any competence reducing factors (e.g.,
impaired vision, physical handicaps, medication, narcotics, alcohol),
perception of hazard, user attitude, inability to read instructions, and how
victim was clothed if relevant, etc. Indicate any competence related
factors related to those injured and any other factors relevant to injury
occurrence.
- Specify activity and location of user (responsible for cooking) at the
time of the incident, and general activities of the household that day which
might affect use of the product. If cooking had been left unattended,
describe user’s activities during that period. .
-
Specify user’s experience with or knowledge of product, common
usage. Use diagrams to illustrate the use of the range/oven during the
incident. Indicate zrvho was closest to the unit at the time of the fire
and distance from the unit.
D. Description of Product
- List manufacturer’s name, brand name, and model/serial numbers.
Photograph all information from rating plate.
- Specify age of product, date of purchase, condition at time of purchase
(new, used, etc.).
- Specify size of product:
height, width, and depth.
- Specify who installed the range/oven,
man, homeowner, etc.
e.g., professional,
maintenance
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INVESTIGATION
GUlDmINE
- Indicate product history: previous problems including electric shocks,
gas supply and other repairs, modifications or alterations, etc. If repaired,
specify date, type, and who did the repairs (factory authorized repair
service; maintenance or handy man, homeowner, other). Describe routine
maintenance.
- Indicate whether the unit has an exhaust fan or hood, and if it is an
integral part of unit or separate item, and whether ducted. Advise if fan or
hood was filtered and free of grease or other materials, and whether
turned on at time of fire.
- If oven-related fire, indicate whether the oven has a continuous-clean
self-clean feature. Specify oven type, conventional or convection,
microwave, etc. and any other features.
or
- Show arrangement of surface heating units and all controls (both surface
and oven). Specify labeling on all controls. Photographs or diagrams are
extremelv imoortant.
- Specify type of controls, e.g., push and turn, push button, etc.
- Specify wattage rating and dimensions of surface heating elements
(burners)--usually stamped in area where element plugs in.
.
- Specify surface burner element types (e.i., halogen, radiant, solid,
conventional coil, gas burner module, etc.).
- Describe type of gas used, LP-gas or natural gas, and type of ignition
system.
- Determine if gas burner needed flame adjustment; i.e., a good flame is
clear/ blue and hardly visible in a well-lighted room, but a yellow-orange
flame indicates need for cleaning or adjustment.
- Describe any previous or current problems with gas supply, e.g., turning
on burners, over pressure, etc.
;’
- Describe condition of product before the fire.
Page
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INVESITGATION
GUIDELINEI
E. Product Safety Standards
CPSC does not have mandatory standards on electric or gas free-standing
ranges, or separately installed ovens or counter-top surfaces. Voluntary
standards for these appliances include the following:
_
Electric:
- Gas:
III.
UL 858 Standard for Household Electric Ranges
ANSI/A.G.A
221.1
Standard for Household Cooking Gas Appliances
INSTRUCTIONS FOR PHOTOGRAPHING
RELATED TO THE INVESTIGATION
AND/OR DIAGRAMMING
FACTORS
Photograph whole product and its environment.
Also, photograph and label
location of fire ignition (e.g., control, connector, element) and the rating
plate. Diagram and label surface elements and all control placements and
settings of the surface cooking or oven that are relevant to the incident. If
accessible, photograph date tag on the flexible connector, if relevant.
Try to photograph product with utensils and appliances in their positions at
the time of the incident.
IV.
.
INSTRUCTIONS FOR OBTAINING
THE INVESTIGATION
SAMPLES AND DOCUMENTS
RELATED TO
Stipulate whether the fire department was summoned and obtain a copy of
the incident report. Obtain copies of any insurance, utility, or repair reports,
installation instructions, maintenance records, and a summary of medical
records, if applicable.
If the fire resulted from component failure and component is available,
contact Mai Ngo, ESEE, (Electric), Ronald Jordan, ESEE, (Gas), or Linda
Smith, EPHA, to discuss sample collection for the Directorate for
Epidemiology.
Before collecting component samples for the Office of
Compliance and Enforcement, contact CECA.
L
Page
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INVESTIGATION GUIDELINE
Attachment
DATA
RECORDING
A
SHEET FOR RANGE/OVEN
FIRES
Complete for all fires. To be attached to CPSC Form 182, Epidemiologic
Investigation
Also complete Attachment
B if
Report, along with a copy of the Fire Incident Report.
the fire was cooking-related,
either attended or unattended.
Incident
Task Number
A.
PRODUCT
IDENTIFICATION
Copy and photograph
1. Fuel:
0
Product
all information
0✔
Electric
If gas, indicate
2.
Date
in fire:
Range (combination
cooking surface and oven)
Installed
oven (separate)
Installed
cooking surface
Manufacturer:
4.
Model No.:
6.
Rating:
L7
✔ Other
Gas
type of gas being used:
involved
3.
on rating plate or tags:
a) Gas input rating (BTU’slhrJ:
b) Electrical
rating:
6.
Date manufactured
7.
Serial No.:
How
8.
Standards
Amps
(from rating plate):
long has consumer
Voluntary
Watts
Volts
had rangeloven?
Certification:
Page
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31
.
lNVESIlGATION
9.
Surface
a.
Cooking
Features/Controls:
Location:
Push button
Is there an indicator
light for the surface
Yes
If yes, are there individual
lights for each heating
light work for the heating
Yes
10.
Do any surface
specify which:
e.
If gas-fueled,
heating
specify
.
elements
Elements
Surface
Heating
Element Types:
Solid disk
a.
Location
b.
Diameter/size
c.
Power
d.
How
Radiant
heating
of involved
rating (stamped
element
Screw
temperature
sensor?
If yes,
non-electric):
Coiled,
plug-in
Quartz-halogen
unit that was involved
of surface
heating
or burners have an automatic
or Burners:
_
heating
unit involved?
ignition type (electric,
Heating
For surface
unit?
No
-
Surface
_
units?
No
Yes
d.
heating
No
-
Did the indicator
Touch
Push & Turn
Turn only
_
Other (specify)
Side
Back
Front
b. Type:
c.
GU-ID-
Coiled, hard-wired
lamp
Induction
cook-top
in the fire, indicate:
unit involved
in the fire (e.g., right rear):
element:
near connection):
was connected
terminations
to range:
(specify number
on involved
unit)
Plug-in tabs and receptacle
If tabs,
describe
shape (e.g., loop, flat blade):
Quick connect
terminals
Page 1O'of 31
INVESTIGATION
11.
Oven Features
(if oven was involved
Self-cleaning
GUIDEZINEI
in fire):
Continuous-cleaning
control
control
Timer control
Clock control
Broil element
Is there an indicator
Other
Rotisserie
Bake element
light for the oven?
No
Yes
-
(Complete
Attachment
B. INCIDENT
12.
C.
Type:
a
Cooking
Fire, either attended
or unattended
n
Gas leak (explain, for example:
leak in flexible connector or gas control valve, gas
line/pipe rupture, loose gas fitting, malfunctioning
pilot light, gas control valve, etc.)
0
Other Component
0
Connection
0
Used for heating
room
0
Left on following
power
0
Left on inadvertently
a
Other (specify;
Malfunction
B also)
(Specify)
Failure (specify)
13.
If gas-fueled,
14.
If yes, describe
outage
(nothing
e.g., potholder,
on range)
clothing
was burner flame abnormal?
ignition):
Yes
No
color and height of flame:
VICTIMW
15.
Number
deceased:
16.
Number
injured:
Page
of
31
INVESITGATION
17.
Is there a detector
0
Yes
(smoke,
0
CO, heat1 present
U
No
GUIDELINE
in the dwelling7
Unknown
18.
If yes, specify
type:
19.
Detector
off (alarmed)?
20.
If no, do you know any reason why not; e.g., not powered,
21.
Before the fire, indicate
went
E. SOCIOECONOMJC
22.
Education
0
23.
24.
Q
No
Unknown
fire too small, etc?
the odor of gas was detected:
U
Less than high school
Rent
Completed
n
high school
home market
0
$15,000
- $34,999
a
$35,000
.
+
value:
0
Own
Provide general description, including all other relevant
the investigation form, CPSC Form 182.
factors
and information
Page
.
Some College
income:
LT $15,000
General Description:
0
level of head of household:
Approximate
U
whether
Yes
DATA:
Total household
17
LX
12 of
on
31
lNVESlTGATION
&JIDELlNE
Attachment
DATA
RECORDING
B
SHEET FOR COOKING-RELATED
(To be attached to CPSC Form 182, Epidemiologic
Attachment
A and copy of Fire Incident Report)
1.
Size of pan involved
2.
Comparison
in fire (bottom
of pan diameter
diameter
to heating
Investigation
in inches/capacity
unit diameter,
FIRES
Report,
along with
in quarts):
(if appropriate):
pan smaller
pan larger
*
pan same size
3.
Pan type,
4.
Burner/element
5.
Describe
food that was being cooked:
6.
Describe
cooking
7.
Type and amount
8.
Was the pan covered7
9.
What was burning when fire was discovered?
10.
material
(e.g., aluminum
saucepan),
control or oven temperature
process (sauteing,
of cooking
List all items that burned,
and condition:.
setting
at time of ignition:
boiling):
oil at time of fire:
or general extent
of flame damage:
.
11.
Length of time that food cooked prior to fire:
Page
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INVESTIGATION
12.
GUIDELINE
Who was doing the cooking?
Age
13.
User’s experience
(indicate
general history of use of appliance):
0
Several times a week
0
Other (Specify)
14.
Time of day fire started:
15.
Was anyone
in the kitchen
0
when
Once a week or less
ignition
0
Once a month
or less
occurred?
Who?
Indicate
where the nearest
16.
Was there an exhaust
17.
Was a reflector
__
Was the reflector
yes
No
Yes
under the surface
heating
element
at the time of the fire?
No
pan covered
-
were at the time of fire:
fan in operation?
pan (drip pan) located
Yes
18.
occupants
with anything
(to keep it clean)?
No
If yes, what?
19.
20.
In the past, had the consumer
Had the consumer
General Description:
experienced
turned the wrong
previous flare-ups
heating
element
on or off?
(gas)?
Provide general description, including all other relevant
the investigation
form, CPSC Form 182.
factors
and information
on
Page 14 of 31
_.
.--
Attachment
BACKGROUND
TECHNICAL
..
C
INFORMATION
I. Electric Section:
Electric Ranaes - General Information’
Counter
level ranges (left consist of a cook-top
level and an enclosed
the clearance
oven located beneath
between
with multiple
the cook-top.
the top of the cook-top’s
surface elements
The clearance
located at counter
“A” is the distance
cooking surface and the bottom
between
of an upper building
cabinet.
Some ranges (right) have a second oven located above the cook-top
commonly
referred to as eye-level
at eye-level
and are
ranges.
7
‘Provided
by Underwriters
Laboratories,
Inc.
Page
15 of
31
-.
INWSI’IGATION
1.
Cook-too
Section
There are several types of electric
four coiled sheathed
inexpensive,
GUIDELINE
elements
arranged
range cook-tops.
in a rectangular
The most
pattern.
popular configuration
These elements
employs
are relatively
have relatively
higher power
and shorter heat up times than other types and have been on
the market for many years.
Most models
have removable,
by the user.
Power
ratings generally
are designed to be connected
range from less than 1200
to either 240
the back and can be lifted for cleaning.
immediately
beneath
the heating
plug-in heating elements
or 208
Volts.
Coiled heating
element
Watts to 2600
Most coiled element
element
generally
to help catch spilled food.
that can be replaced
Watts.
Most elements
cook-tops
are hinged at
include a drip bowl located
These drip bowls are removable
for
cleaning.
Another
elements
common
have become
cook-top
widely
element
available
popular in Europe for quite a long time.
the heating element
temperatures,
elements.
elements
imbedded
In order to have efficient
Solid disk elements
heat transfer
are constructed
and can automatically
are sealed to prevent
These elements
have electrical
Glass or ceramic,
gained additional
popularity.
opaque glass cooking
from the element
to the cooking
smooth
for ease of cleaning
Induction
ceramic cooking
using infrared
level.
utensil,
these
without
imbedded
coiled
dents or
in the iron disk
with a pot that has boiled dry,
Nearly all solid disk element
beneath the cook-top.
use radiant heating
radiation
cook-tops
elements
include one or more quartz-halogen
located
beneath
lamps.
elements
include a limiter thermostat
internal
begins to overheat.
a clear or
utensil.
Some
These quartz halogen
reduce the time needed to heat the cooking surface.
As with solid
to cut power to an
Glass cook-tops
are sealed
parts and wiring from spillage.
are similar to glass-ceramic
However,
for many years and have recently
to heat the glass and the cooking
if the glass cooking surface
and to protect
surface.
or reduce the power
These cook-tops
elements
element
the element
top units have been available
nearly all glass cook-top
heating
flat bottoms,
a “limiter” thermostat
spillage from accumulating
lamps heat very rapidly and sharply
disk elements,
contain
of
ratings similar to coiled elements.
surface,
of these radiant heating
portion
higher initial cost than the more traditional
caused by operating
turn off the element
with the active
This results in more stable cooking
must be used with pots and pans that have nearly perfectly
Most solid disk elements
These
only within the last 10 years, but have been
in a heavy cast iron plate or disk.
that can sense high disk temperatures
individual
in North America
longer heat up times and somewhat
other deformations.
cook-tops
type is the solid disk or cast iron element.
induction
cook-tops
cook-tops
in that they use a sealed glass or
heat the pot or pan using a magnetic
field rather
Page 16 of
31
INWSI’IGATiON
than a heating
electronics
element.
As a result, the cooking surface
to control the cooking temperature
Induction
cook-tops
generally
remains relatively
and are rather expensive.
user with the most control of cooking temperatures
available.
GUID-
from glass-ceramic
have lower power
user instructions
type controls
cook-tops
with glass-ceramic
A few
Induction
Induction
controls
vs. the predominant
cook-top
cook-tops
on
provide the
design
and
can usually be
in product
marking
use of conventional
units.
range cook-tops
cook-tops
ratings than other types of cook-tops
by the use of the word “Induction”
or by the use of electronic
They rely heavily
and are the most energy-efficient
must be used with iron or steel pots and pans to cook effectively.
distinguished
cool.
and
“knob”-
._
include
a grill or griddle.
These units are designed
to heat food
directly rather than using a pot or pan.
Some range cook-tops
type of heating
disk elements
receptacle
element.
2.
For example,
and a second module
arrangement
coiled element
.
that allows
module
Cook-too
units that can be removed and replaced
a range may be provided
consisting
of a grill.
module-all
range cook-top
elements
without
are provided
disturbing
are controlled
from Low to High, and are commonly
device does not sense or detect the temperature
power
is controlled
and back again - repeating
the “off” position.
The modules
consisting
of two solid
with a plug and
the appliance
wiring.
Controls
heat settings,
heating element
with one module
with a different
the user to remove the grill module and replace it with a griddle,
or glass cook-top
Most electric
continuous
are modular
of the heating
by switching
the heating
by cycling-type
called infinite
element
element
switches
switches.
or cooking
with
This type of
utensil.
from full power,
Instead,
the
to zero power,
the cycle over and over every few seconds until the user turns the control to
The control setting
determines
the amount
of On time and Off time during each
cycle.
A few coiled and solid disk cook-top
copper or brass capillary
tube, containing
located in the center of the heating
increases,
elements
a small amount
element.
determines
Range cook-top
the temperature
controls
the oven door), on a backguard
located
located
of the pot and the thermostat
element
elements,
A
disk
The
cycles on and off.
either in the front of the cook-top
behind the cook-top
switch.
to a small sensing disk
to send a hydraulic signal to the control.
at which the heating
are generally
by a thermostat-type
of fluid, is attached
As the temperature
the fluid inside the capillary tube expands
control setting
are controlled
or arranged
(just above
in a line to the left or
right side of the cook-top.
Page 17 of
31
All range cook-top
Conventional
cook-top
“knob”-type
controls
3.
controls
controls
necessitate
need two distinct
operations
to energize
require that the knob be pushed-in
the actuation
of two separate
buttons
a cook-top
prior to turning;
or touch
element.
electronic
pads.
Oven Section
The oven of an electric
holding food, two
baking heating
range consists primarily
or more sheathed
element
located
heating
beneath
elements
of an insulated
and a thermostat.
steel box, a door, racks for
A standard
the oven racks and a broiling heating
oven racks.
oven includes
element
located
a
above the
_
In the bake mode, heat in the form of infrared
broil) element
causes the temperature
radiation
from the bake (and sometimes
of the oven walls to increase.
The oven walls,
the
in turn, heat the air
and food inside the oven by conduction.
In the broil mode, food is cooked
by infrared
radiation
from the broil element
rather than by
hot air.
Oven bake elements
elements
are rated in the 3,000
are generally
to 3,600
Some ovens are provided
within the oven cavity
oven temperatures
compared
oven is raised to approximately
to water
a pyrolytic
1,000
surfaces
or self-cleaning
usually 400
‘micro”
in product
markings
located
broil
hot air is circulated
lower
for 2 - 3 hours, reducing
of ash.
inside the
any food residue left
During the self-cleaning
An inert catalytic
degrees Fahrenheit
cooking
to break down
coating
on the
as the oven is operated
or higher.
capability,
either in a separate
They can usually be identified
by the words
oven located
“Microwave”
or
on or near the oven controls.
Many oven doors are provided
inside the oven without
in which
cycle in which the temperature
cleaning feature.
Some oven designs include microwave
oven cavity.
Most
a fire or burn hazard.
ovens include a continuous
or in a common
Watts.
baking.
of the oven cavity causes food particles on the surfaces
at eye-level
and 2,600
food to be cooked faster and at slightly
vapor, carbon dioxide and a small amount
at higher baking temperatures,
Watts
cooking feature
degrees Fahrenheit
cycle the oven door is locked to prevent
A few
This allows
to conventional
2,000
range.
with a convection
by a fan or blower.
Many ovens feature
inside thsoven
Watt
rated between
with a window
and oven lamp to allow the user to view food
having to open the oven door.
c
Page 18 of 31
INVESIIGATION
GUIDEJJNE
II. Gas Section
A.
Gas Ranaes-General
Modem
Information’
gas ranges incorporate
pressure regulators
and automatic
controls for programmed
cooking,
automatic
requirement
National
is accomplished
such as thermostats,
gas valves.
In addition,
self-cleaning
oven controls
All of these ranges must be equipped
with current American
controls,
Standards
with automatic
Institute
by manufacturers
today’s
(ANSI)
pilots, gas
gas range may incorporate
specialized
or meat probes.
ignition of all burners in order to comply
standards
in different
automatic
ways,
for domestic
and further
gas ranges.
differs
This
in various sections
of the range.
For example,
tube ignition.
automatic
In this system,
ignition
of the top burner of a gas range is usually accomplished
a small metal tube called a flash tube conducts
air and gas from the burner cap to a standing
standing
pilot ignites this mixture
air-gas mixture
(Note:
pilot.
the standing
which then burns (“flashes
issuing from the flash tube injector port.
or slots to ignite the air-gas mixture
pilot.
throughout
system
The high voltage
the range by high tension
Another
means of automatic
the burner directly,
in an electronic
ignition
coil (glow coil) which
glow coils remain hot for a few seconds
employed
circuit which
in gas ranges is the electric
gives off sufficient
the
is usually
is distributed
The system
type of ignition system
glow coil.
employs
This
a small
heat to ignite the pilot gas when energized.
circuit is activated.
Some electric
after the pilot gas is ignited and then are shut off usually
Others may remain energized
Another
ports
leads.
The gas to the pilot is usually turned on at the same time the electrical
flame switch.
by carryover
thus eliminating
energy for providing the spark(s)
usually is used to light gas pilots for oven or broiler burners.
electric resistance
The
at the main burner ports.
The energy for the spark is developed
located at the rear of the range.
lit).
of
the flash tube to ignite the
This flame is carried upward
Spark ignition may be used to light the gas issuing’from
need for a standing
a fast burning mixture
pilot is manually
back”) through
by flash
by a
while the circuit is activated.
often found in the oven section of the range is the two stage gas
pilot.
Automatic
pilots incorporated
The bulb sensor is rigidly mounted,
American
in gas range ovens are usually of the mercury
since its position
vaporization
type.
with relation to the pilot flame must be maintained.
L
*Material on the operation of gas ranges has been used by permission of the copyright
Gas Association (A.G.A.) Catalog No. XH1275,
Printed in U.S.A., 5M3.84-2.5-2.0-577.
Page
holder,
19 of
31
.
I
INVESTIGA’IION GUIDELINE
Also, the complete
pilot assembly
the burner it is designed
(pilot burner and sensor) must be maintained
to light.
in a fixed relationship
to
For this reason most range oven and broiler burner pilots are mounted
directly on the burner.
Top burner range controls
In addition
infinite range of flame settings.
temperature
controls.
controls
are available.
They are the tower
bulb positioned
operated
gas valves which
to these basic top burner controls,
There are two basic types of top burner automatic
and the bypass type.
As the pan bottom
liquid exerts pressure
Both of these sense temperature
gas control valve,
top burner
temperature
by a liquid filled
with the bottom
of the
gets hot so does the sensor, and the liquid in it’expands.
This
top burner temperature
The expanding
acting to gradually
control,
as the cooking
In turn, the minimum
The minimum
cooking temperature
is limited by how small a bypass rate can be used with stable flames.
can be used, the lower will be the minimum
there is always
a flame
load (pan) heats up
fluid in the sensor bulb exerts an increasing
reduce gas flow to the burner.
used is referred to as the bypass rate.
the bypass system
an
in the gas valve to control gas flow to the burner.
In a bypass type of automatic
the sensor bulb also heats.
have virtually
automatic
in the center of the burner so that the bulb makes direct contact
vessel being heated.
expanding
are simply manually
temperature
indicated
pressure in the
gas rate which
which
is
can be attained
The smaller the bypass rate that
on the thermostat
control
present at the main burner ports in normal
dial.
With
cooking
operations.
The tower
..
operations
there is always
position.
maintain
burner system
The temperature
a flame on the tower
burner near the main burner.
During normal cooking
burner as long as the main burner gas valve is in the on
sensor in this case acts to cycle the main burner flames
the set temperature
maintained
uses a small tower
with this system
in the cooking
depends
load.
The minimum
load temperature
on the gas input rate of the tower
burner.
on and off to
which
can be
The tower
burner also
serves to reignite the gas at the main burner ports each time the main burner is cycled on.
The primary advantage
tower
system
1.
is that it permits
of the bypass system
lies in its simplicity.
The primary advantage
of the
control at a lower temperature.
Gas Oven Controls
Control
through the years.
temperature
of oven temperature
by automatic
means has been accomplished
in various ways
But in all cases an automatic
in the oven, and (2) an automatic
fuel to the oven burner.
These two
oven has (1) a temperature sensor that responds to
;
valve that responds to the sensor and controls the flow
devices can be combined
of
into one unit called an oven thermostat
Page 20 of 31
.
-
INVESTIGATION
valve.
The sensors used in most gas ovens today are the liquid or gas filled bulbs with capillary tubes.
Control of the flow
a.
of fuel can be accomplished
Modulating
temperature,
burner.
between
resorted to modulating
the limits set by maximum
This system
temperatures
ordinarily
as low as 250
would
provide,
to the control setting.
temperatures
250
Cycling
previously
Oven Control
electrical
stable flame on the oven
controls
stable flames
is called the bypass rate.
is that they provide a uniform
Their chief disadvantage
is their inability
temperature
to maintain
in the
oven
Systems
have been developed
oven temperature.
discussed.
gas rate used and minimum
F.
Several systems
off to maintain
the flow of fuel to obtain the desired
gas rate providing
of modulating
oven corresponding
b.
or cycling of the oven burner.
when used with proper burner and oven construction,
F. The minimum
The chief advantage
below
either by modulation
Oven Control Systems
Early gas control systems
One system
This all-gas two-stage
that use the method
incorporates
pilot system
of cycling the main burner on and
the two stage pilot valve which
has the advantage
has been
of not being affected
by
supply problems.
In another
switch
GUlDmINE
which
switches
cycling system,
controls
a liquid filled thermostat
an electrically
is a pilot flame switch.
operated
This switch
solenoid
low oven temperature
of the modulating
below
250
F.
2.
Controls
for Self-Cleanina
There are two
pyrolytic
system
continuous
different
simply
and cycling systems
oven temperatures
can be incorporated
valve modulates
to maintain
very
down to a low bypass
as low as 140 F.
Gas Ovens
systems
and the continuous
clean system
valve
extinguished.
In this case, the thermostat
rate and is then cycled on and off to maintain
Also, in series with the thermostat
gas valve.
opens the electric circuit to the oven burner solenoid
if the source of ignition for the oven burner becomes
A combination
bulb opens and closes an electrical
used in today‘s
clean system,
employs
modern
(sometimes
special catalytic
gas self-cleaning
ranges:
referred to as a catalytic
The
cleaner).
oven liners which are continually
The
self-cleaning
during the normal oven operation.
The pyrolytic
burn off any cooking
and satisfactorily
system
involves heating the oven cavity to wproximately
soil or spillovers.
For example,
a special door lock mechanism
of the oven door when the temperature
eliminated
Special controls are necessary
from the oven flue products
800
to complete
this function
must be incorporated
inside the oven cavity is greater than 675
F to 1,000
F.
to prevent
F to
safely
opening
Smoke must be
and they must be cooled before they are vented
to the kitchen.
Page
21 of
31
INVESTIGATION GUIDELDIE
The oven must be capable
temperature
sequence
of operation
First, the oven selector
switch
door is closed and locked into position
desired length of cleaning
The waist-high
supplied
for a pyrolytic
by an electric solenoid
time (usually between
When the oven cavity
any current
l-1/2
position.
lock.
is quite different
gas oven would
reaches a temperature
lock.
process is started.
the oven burner is automatically
of 675
F, a bimetal
switch
opens,
As a result, the oven door lock handle cannot
At the end of the cleaning
cycle, the clock timer acts to shut off gas
broiler burner and oven burner and the oven cools down.
lock prevents
of the oven door until temperature
opening
proceed as
The clock timer is then set for the
flow to the waist-high
3.
than the
At the same time the oven
and 2 hours), and the cleaning
After a few minutes,
flow to the electric solenoid
be moved to the unlocked
self-cleaning
is turned to the “clean” position.
broiler burner comes on first.
with gas.
preventing
F range which
range used in normal oven operations.
A typical
follows:
of being cycled in the 800 - 1,000
The electric solenoid
in the oven has dropped to below
675
F.
Broiler Burner Controls
There are two
“waist-high
broiler.”
Several rack positions
basic types of broilers found in domestic
The low broiler is located
are provided
fats to drain into the bottom
The gas controls
in the bottom
for the broiler pan.
gas ranges; the “low broiler” and the
of the range below the oven/broiler
The pan has small openings
to permit cooking
of the pan.
used with the low broiler are the same as the oven controls
burner is used for both broiling and baking operations.
There is one exception:
one additional
the oven/broiler
position
burner.
marked
“broil.”
In this position,
since the same
the oven thermostat
has
burner will remain lit or it may
cycle on and off or modulate.
The waist-high
additional
broiler is located
space is freed in the bottom
any broiler spattering
A separate
diverter-type
of the range for storage.
of the oven walls can be automatically
broiler burner and pilot are necessary
pilot valve.
simultaneously.
at the top of the oven cavity.
This valve is necessary
to prevent
With this arrangement
If the range is a self-cleaning
type then
self-cleaned.
in the waist-high
operation
broiler, along with a special
of both the oven and broiler valve
At a cold start this valve is open to the oven burner and closed to the waist-high
broiler
burner.
The sequence
for broiler operation
turned to the broil position.
glow coil.
This permits
is as folloks:
The combination
gas to flow to the broiler pilot where
When the broiler pilot sensor is heated
it causes the diverter
oven/broiler
thermostat
is
it can be ignited by a
valve to switch
from the
Page
22 of
31
INWSI’IGATION GUIDELINE
normally
open oven position to a closed oven position and to an open broiler position.
the broiler burner where
is turned to an oven position the broiler pilot gas is shut off and the
oven pilot gas is permitted
to flow.
valve assumes
open oven position
its normally
If an electric solenoid
As a result, the broiler pilot sensor is not heated,
valve system
on the oven or broiler burners.
flame switch
incorporates
to
it is ignited by the broiler pilot.
When the thermostat
to switch
Thus gas flows
sensor is used to detect
a flame switch,
while the two-stage
oven pilot is heating
is used, a simple electric thermostat
pilot flame and ignite the oven burner.
of infrequent
up its sensor.
switch
Usually in this type of system a standing
but because
so that the diverter
can be used
type oven pilot with a
The broiler pilot also
use has its pilot ignited by glow coil each time
the broiler is put into operation.
4.
Gas Pressure Resulators
The gas range, like other gas appliances
limits and will perform
safely and most efficiently
gas pressure regulator
is installed
is designed
within
to operate
this range.
in the gas range manifold
within
Therefore,
certain gas pressure
for purpose operation
to supply a constant
a
gas pressure to all of
the burner orifices.
On ranges, the regulator
near the top burner valves.
direction
properly.
In this position
of the gas flow through
regulators
is usually located just under the top section
it is easily reached for any adjustment
the regulator
must have the direction
and toward
of gas flow
is essential
for its proper operation.
clearly marked
needed.
the front
Correct
All design certified
on them so that they can be installed
.
The mounting
position
(upright,
on its side, up-side down,
Btu per hour
etc.) of some regulators
Btu per hour
Two top burners at
9,000
each
18,000
Two top burners at
12,000
each
24,000
Griddle burner
10,000
10,000
Low oven buyer
25,000
25,000
Elevated
13,000
13,000
Total
oven burner
is critical.
90,000
Page
23
of
31
INVESTIGATION GUID-
Capacity
For example,
is another
factor that must be considered
a range may consist
of the following
capacity
of at least 90,000
The operating
designed to operate
Domestic
Btuihr.
Btulhr.
gas ranges ordinarily
of about 4 to 6 inches water
are equipped
column.
Therefore,
for a range.
at the same time:
a regulator
with a maximum
must be selected.
pressure range of the regulator
in the pounds-to-pounds
a regulator
burners that could all be operated
The total input rating for this range is 90,000
regulation
when selecting
also must be considered.
range, while others regulate
with the inches-to-inches
Range regulators
Some regulators
in the inches-to-inches
type supplying
should be marked
P which
an outlet
indicates
are
range.
pressure
they are
designed to handle pilot gas flow.
5.
Manual
Valves
a. Shut-Off
Valves
A manual
positive shutoff
necessary
shut-off
valve should be used with a gas range to provide a me&s
of the range gas supply for servicing
if a burner valve had become
appliances
on the same supply line.
defective
and replacement
purposes.
and has to be replaced
On a range, the shut-off
Shutoff
without
valve is located
of complete
would
disturbing
be
other gas
ahead of all controls.
b. Top Burner Valves
Most range top burner valves are manual
controlled
top valves.
6.
Timers
The manual
The exception
would
be thermostatically
valves are usually of the plug and barrel type.
and Clock Controls
One useful accessory
may be digital or have sweeping
programmed
cooking
self-cleaning
sequence;
having settings
valves.
found on most gas ranges is the timer and clock control.
hands and can be used to:
such as start and stop cooking
(4) provide a timed
from one to sixty minutes.
(1) indicate time:
and cook and keep warm;
convenience
The clock
(2) control the oven during
(3) start and stop the
outlet; and (5) provide a minute
minder usually
At the end of the timed period, an audible sound is supplied
by a buzzer.
Page 24 of 31
lNVESITGATION
GUIDELINE
ELECTRK
_ ._
Page 26 of 31
_. . . .
.__
_
.
INVESITGATION
GUIDELINE
B. Flexible Connector
Flexible connectors,
generally
Some incidents
may result in fires and/or explosions.
end-fittings
and stress corrosion
leaks developed.
resulting
but to a lesser extent
Also, connectors
in stress corrosion
and window
cleaners,
ranges, have exhibited
bodies with either butted
with the lapped surfaces,
can be over-stressed
in the presence
and oven cleaners.
gas leakage which
have been traced to failure of soldered
of the brass tubes of the connectors.
were brazed or soldered to connector
butted surfaces,
used with free-standing
of ammonia
Prior to 1973,
or lapped surfaces.
corrosion occurred
during installation
or brazed
some end fittings
Particularly
with the
in the joint, and
or movement,
vapors from such products
as floor waxes,
floor
..
Page 25 of
31
INVESIIGATION
GUIDELINE
ELECTRIC
99
Fenture Index
I
Storage
Device
3 Anti-Tio
Label
Bake Unit
wiping
QQQQ
wx rll match h*e a11feaum.
Drawer
2 And-Tip
4
QQ
May
oven f&r.
(on some models)
I4 Surface
Unit On Light
IS Cooktoflift-Up
Cooktop
(on some models)
be
lifted gendy for
_
5 Broil Unit
I
1
I
16 Oven Vent
Located under right rear surfxe
unit.
17 Model and Serial Number Locztion
Located behind the range door or
behind the storaec dower.
6 Oven Door La&
use for Self-cleul only.
7 Surface
Units, Drip Pans
8 Surface
Unit Controls
,;
/
$j~~~;;ndo-,
19 Oven Shelf Supporu
Shelf positions for cooking are
suggested in tie Baking. Roasting
and Broiline sections.
-0
1 I Clock and Timer
(on some models)
12 Oven On Light
Latch Door Light
Preheated Light
Automdc Oven Light
(on some mod&)
Oven Shelf with Stop-lockc
(number may vary)
11 Rcmovnblc Oven Door with
Broil Stop Position
!&iIv removed for cleannine.
21
OvenDoor Gasket
I
13 Oven Temperature Knob
I
Page
27
I
of
31
INvEsLlGATION
GUIDELINE
GAS
Features of Your Range
Page 28 of 31
_
INVJBTIGATION
GUID-
GAS
Feature Index (Not all mcdeh have aI1 fe-.
Appevvlce
of features varies.)
I Backguard (on some models)
2 Surface Burners. Drip Pans (on some mode!s) and Gtaus
3 Oven Luno On/Off Switch (on some models)
4
Clock
5
OvenVent (locared
I
and Tuner (on some models)
6 BAKE/BROIL
on cwktop
I
on some models)
Switch (on some models)
7 OvenConrml
I
8 Surface Burner Controls
I
9 cooktop
10 Bmiler Pan and Rack
11 Oven Shelves (number of shelves vuia)
I?- Oven Shelf supports
13 +.ir ‘fen! in Oven Door (located at
14 Broiler Drawer or Stonqe
I5
top
of Oven Door)
I
D~~wvcr(dependioq on model)
Air InLake
1
16 Model and Serial Numbers @x.xcd oo front frame of range.
behind either Broiler Dnwer or Stonge Drawer)
17 Removable Oven Door
18 Anti-Tip Device (Lxxed
right rear ax bxbxn. See Insulladon Inrmrcriom.)
19 Oven Bottom
20
I
Oven InurIor Light (on some models)
-
.
.
Page
29
of
31
INVESTIGATION GUIDELINE
GAS
6a. ELECTRIC IGNlTlON SURFACE
BURNERS
OPERATIONOFSURFACE
BURNERS
ThlS range 1s equipped wth one of lhe lhree burner
F/pas shown below.
Operation of llectnc igniters should be checked after
range and supply line connecfors have been carefully
fi%cked for leaks and range has been connected :o
eltctnc power. To check for proper lighling. pusn !n
and turn a.surface burner knob to Ihe LITE positron.
You wtll hear the ignller sparkmg. The surface burner
should light when gas IS wadable to Ihe top burner.
Each burner should light -wthm four (4) seconds rn
normal operalion after air has been purgca from
supply lines. Visualfy check that burner has III. Once
the burner lights, knoo Would be rotated out of the
LllZ pos~tlon. There art separate lgmtron dewces for
each burner. Try each knob separately unbl all burner
valves have been checked.
UNEAR
FLOW
VALVE
III
11
THREE
POSlllON
VALVE
KNOB STYLES MAY VARY FRCM
PICTURED ABOVE.
VENTURI
SME
11
TWO
POSITION
VALVE
TnOSE
6b. STANDING PILOT SURFACE BURNERS
Afterrange and suppiy line tonnectlons have been
Carefully checked for leaks. purrje air from the
sys:em. The standing pilots must be lit immcdlateiy.
proceed as follow3:
1. Lilt mu” top. and locate top burner pllol
adjustment.
2. noId match over top ptlot until lit. After one pilot is
IA. ngnt the otflcr pIlot.
3. When both p~lors are lit. adjusl Ihe loo pllor
adiwtmenr unul the otlou are approxtimatq 1% fall
mth a very align; yellow tip.
I
SNAWN
STVLC
DUAL
smE
CHECK SURFACE BURNWS
To check for proper tightmg. push in and turn a
SU~~SZO
twnef knob to the UTE po%tmn. Each
burner should light wthm few (4) seconds in normal
oparatmn. Once the burner lights. knob should be
rotatedout of Ihe UTE poshon. Try each knob
scparatety unr~l all burner v&es have been checked
Page 30 of 31
.
INVESTIGATION
GUIDELINE
GAS
OPERATIONOF OVEN BURNERS
AND OVEN ADJUSTMENTS
9a. ELECTRIC IGNITION BURNERS
Operationof alcctrictgnitcnshould be checked aher
range and supply line connectors have been carefully
checked for leaks and range has been connected 10
alectric power.
The OVM~burner is CqUrppedwilh an elactric conuol
system as well as an llectnc oyen burner ignrter. If
your model is equpped mth a m&high
broil burner.
it will alao have an elecmc burner ~gnner. These
conuol systems requira no ad)usunent. When the
oven b set lo operate. a~rrent wll flow lo the igrwer.
It will ‘glowC similar lo a liih! bulb. When the ~gnrter
has reached a lemperature sti.z~cn! IO qmte gas, me
electncally coruolled oven vatve will open and flame
will appear al Ihe oven burner. There usa ttme lapse
from 30 to 60 seconds after the thermostat is turned
ON before the flame appears at the oven burner.
When the oven reaches the dial setting. the glomng
ignner WIII go off. The burner flame wll go ‘out’ in 20
IO 30 seconds aher the ignner goes ‘OFF’. To
maintain any given oven temperature this cycle wtll
continue as long as Ihe dial (or display) is se1 lo
operate.
.
After removing all packing materials and literature
from the oven:
1. Se1 oven 10 BAKE a: 330.. see QWNERS
GUlDe
for owratlna u1sm~d10~.
2. Wtihin 60 seconds (he oven burner should ignite.
Check for proper llama. and allow Ihe burner lo cycle
once. Rose1 con1rols to off.
3. If your model is caulpped wth a wars&high broiler,
sel oven lo BROIL. sea OWNER’S GUIDF for
operabng instructvans.
4. Wrthrn 60 Seconds Iha broil burner should Igmte.
Check for proper flame. Resel controls to off.
9b. STANDING PILOT OVEN BURNER
To
light the oven ~8101proceed as folkws:
Turn Ihe oven thermostat knob lo -Off. Remove
oven bottom. see step 10 for instructions on removing
Ihe oven bonom. Light Ihe oven prlol mth a match.
The oven prloc should bum mlh a stabb flam. after a
faw seconds operawn and should have a small flame
visrble only al lha openmg in lhe lop of the plot
-bly.
.
Page 31 of 31
| File Type | application/pdf |
| File Title | Appendix 6 - Range and Oven Fires |
| Subject | Complete Attachment A for all fires. If fire resulted from cooking-related activity, also fill out Attachment B. Attach to CPSC |
| Author | EXHR |
| File Modified | 2010-03-10 |
| File Created | 1997-05-02 |