Study of Technology for Detecting Pre-Ignition Conditions of Cooking-Related Fires Associated With Electric and Gas Ranges and Cooktops. Phase 1 Report.
Study of Technology for Detecting Pre-Ignition
Conditions of Cooking-Related Fires Associated With
Electric and Gas Ranges and Cooktops. Phase 1 Report.
(7589 K)
Johnsson, E. L.
NISTIR 5729; 115 p. October 1995.
Sponsor:
Consumer Product Safety Commission, Washington, DC
Available from:
National Technical Information Service
Order number: PB96-128095
Keywords:
stoves; appliances; fire detection; fire prevention;
ignition prevention; kitchen fires; residential
buildings; sensors; smoke detectors; smoke measurement
Abstract:
A significant portion of residential fires stem from
kitchen cooking fires. Existing fire data indicate that
cooking fires primarily are unattended and most often
involve oil or grease. The purpose of this
investigation was to ascertain the existence of one or
more common features or characteristics of the
pre-ignition environment that could be used as input to
a sensor in a pre-fire detection device. The ultimate
goal of this continuing study is to evaluate the
feasibility of incorporating such a device into the
range that would react to a pre-fire condition and
reduce the occurrence of unwanted kitchen fires. The
focus of the study was unattended foods placed in pans
on burners set to high heat. Experiments were conducted
with three different foods and with gas and electric
ranges to investigate the pre-ignition environment of
actual range-top cooking fires. Numerous temperatures
in the near surroundings as well as local plume velocity
and laser-attenuation measurements were recorded. A
Fourier transform infrared spectrometer was used to
observe significant species production above the food.
Results of these experiments are presented and
evaluated. The second part of this study was a
literature and patent search of technologies with the
capability to act as either the sensor in a pre-fire
detection device or as the automatic control that would
respond to a detector warning signal by shutting off the
gas or electricity supply. A broad range of potential
detection technologies was reviewed because the pre-fire
signatures had not yet been identified. A bibliography
and comments on the applicability of different
technologies are included. The conclusions pertaining
to the experiments are based on measurements and
observations of combinations of specific ranges, pans,
foods, and ventilation so extrapolation to other
conditions should be performed with caution. The major
conclusions of this research are as follows: (1) Strong
indicators of impending ignition were temperatures,
smoke particulates, and hydrocarbon gases. (2)
Promising detection technologies include: tin oxide
(SnO2) sensors for hydrocarbon detection, narrow band
infrared absorption for hydrocarbon detection,
scattering or attenuation types of photoelectric devices
for smoke particle detection, thermocouples for
thermometry of the burner, pan, range surface (top and
below), or range hood. (3) Logical processing of signals
from two or more of the detection technologies could be
an important means by which false alarms of pre-ignition
conditions are elimianted. (4) Control technologies
exist that are applicable to the safe shutdown and
restart of gas and electric ranges upon detection of
approaching ignition.
