AT THE HUGHES ASSOCIATES RESEARCH FACILITY in Baltimore, Maryland, engineers are conducting experiments on a plain white electric stove. Tubes and wires are hooked up to the appliance, giving it a kind of hospital-patient look. A frying pan containing cooking oil heats atop the stovetop, and gauges monitor the temperature of the pan as the oil reaches the point of ignition. As fire shoots from the pan, sampling ports in a collection hood atop the stove analyze the oxygen, carbon dioxide, and carbon monoxide levels of the smoke and gases emitting from the flaming pan.
Hughes Associates senior engineer Dan Gottuk provides an overview of the research project into standardizing cooking fire mitigation tests.
Hughes Associates research engineer Josh Dinaburg details how the cooking fire evaluation test is set up and performed.
Hughes, a fire protection and engineering firm, is one of a handful of companies and institutions currently analyzing methods to mitigate cooking fires, which are considered the leading cause of home fire structures in the United States
by NFPA. The goal of the Hughes project, which is being conducted under the auspices of the Fire Protection Research Foundation, is to help develop standardized fire scenarios and performance test methods for cooking-fire mitigation technologies, which the Foundation believes is a crucial step in furthering the use of these technologies.
Efforts to diminish the deaths, injuries, and property damage associated with these fires is not new; the National Institute of Standards and Technology (NIST) and others have been developing strategies since the 1980s to mitigate cooking-related fires. An array of cooking fire mitigation technologies — devices placed on and around stovetops that alert cooks of danger and alter cooking mechanisms before catastrophe occurs — has entered the marketplace and is receiving attention from researchers and home fire safety advocates.
But that attention is not translating into the appearance of these technologies in U.S. homes. That’s the result of a number of factors, including the absence of standardized testing methods to evaluate new products. Without those standardized methods, there is no uniform way to distinguish effective mitigation products from ineffective ones, and consumers have no Underwriters Laboratories-style seal of approval with which to purchase cooking-fire mitigation products in confidence. Testing standards are also seen as an essential step toward the possible requirement of such devices in codes and standards, and as the foundation for the type of regulatory cooking-fire awareness campaign that NFPA is gearing up for.
“We haven’t characterized the fire scenarios, and we don’t know what the performance criteria are for these cooking-fire mitigation technologies,” says Kathleen Almand, the Research Foundation’s executive director. “This new project is an important step in the commercialization of these technologies.”
The Research Foundation’s partnership with Hughes isn’t the only project addressing the issue of testing standards for cooking-fire mitigation technology. Other research endeavors, including current projects at Eastern Kentucky University (EKU) and Underwriters Laboratories, have similar scopes and goals.
“The fire society as a whole is focusing on cooking fires in order to limit them,” says Corey Hanks, a researcher on the EKU project. “Finally, we’re seeing more of a push.”
Of the more than 157,000 estimated home structure fires reported annually during the period 2006–2010, cooking caused 42 percent of the fires, 38 percent of injuries, and 15 percent of deaths.
Unattended cooking was the leading contributing factor to these fires and fire deaths.
Ranges, with or without ovens, accounted for the majority of home cooking fire incidents.
Three of every five non-fatal home cooking fire injuries occurred when the victims tried fighting the fire.
Frying poses the greatest fire risk.
Source: NFPA’s “Home Fires Involving Cooking Equipment” report.
Over the years, manufacturers have developed a variety of approaches designed to mitigate cooking fires. Some devices use motion detectors to check for a cook’s presence at the stove and can shut off the burner if nobody is nearby. Other devices douse stovetop flare-ups with fire suppression agents, use smoke alarms to predict pre-fire conditions, and can prevent oil from reaching its ignition point.
NIST approached the Research Foundation in 2010 with a request that it develop an action plan that would further the implementation of these devices. The outcome was the Foundation’s 2011 report, “Home Cooking Fire Mitigation: Technology Assessment
,” which was prepared by Hughes for the Research Foundation and evaluated more than a half-dozen categories of technologies based on fire prevention effectiveness, cooking performance, cost, and convenience.
“We looked at information from a range of sources, including talking with folks in the industry, reviewing patents, and a general literature search,” says Dan Gottuk, senior engineer and director of forensic and litigation services with Hughes and project supervisor for the new Research Foundation project. “There was concern that some of the technologies may adversely affect the cooking process, either in a way that affects food quality or a person’s cooking behavior, but there are other studies that refute that.”
The most prevalent device in the United States, according to researchers interviewed for this story, is the Safe-T Element, which is designed for electric-coil ranges and includes a solid plate cover retrofitted atop the burners. The system, which requires professional installation, includes a unit inside the stove that prevents the plate from exceeding 662 degrees Fahrenheit (350 degrees Celsius), far below the ignition temperature of 728 degrees Fahrenheit (387 degrees Celsius) for most oils and fabrics. To date, there has never been a stovetop fire on a range equipped with this technology, says Kevin Callahan, president and CEO of Pioneering Technology Corp., which produces the product. More than 90,000 stoves within multi-unit housing developments, universities, and military housing across North America have installed the device since its release in 2007. [briefly, why only these types of multi or group occupancies?]
While some companies, including Pioneering Technology, have developed their own safety evaluations for their products, the absence of any standardized test methods is a problem for many manufacturers. “If there was a device someone wanted to bring to the market, how would they test it?” asks Dan Madrzykowski, leader of NIST’s Firefighting Technology Group. Madrzykowski has contributed to the Vision 20/20 Project, an effort by the U.S. branch of the Institution of Fire Engineers that unites individuals and organizations, including NFPA, in developing a national strategy for fire prevention. “That’s what the Foundation’s research is doing — developing an appropriate test to make sure a device is doing what it claims to do.”
Madrzykowski equates the slow adoption of mitigation technology to the implementation of seatbelts and airbags in cars. “One of the challenges of changing what you’re doing now to something different, regardless of the business, is admitting that what you’re doing now is hazardous,” he says. “To be fair, the other thing you don’t want is to be an early adopter of technology. Before you start making a million units and placing them in American homes, you want to make sure it really works.”
Almand of the Research Foundation says stove manufacturers have latched on to the latest research efforts; the Association of Home Appliance Manufacturers (AHAM), for instance, is a member of the steering committee for the Foundation’s new project. “AHAM has been very supportive of the most recent research project being conducted by Hughes Associates,” said Wayne Morris, vice president of Technical Operations and Standards for AHAM, in a prepared statement. “We appreciate that the Research Foundation has involved a large number of stakeholders, government agencies, standards developers, and the manufacturers to discuss a solution.”
Up to the tests
Besides evaluating fire mitigation devices, the Research Foundation’s 2011 report also outlined future endeavors, including the development of what it termed “standard fire scenarios” and the creation of “test methods and performance criteria.” These objectives were addressed by the Hughes researchers, who began testing in April on an array of cooking oils, including varieties with higher free fatty acid compositions that can ignite at lower temperatures and therefore may lead to fire sooner. Factors also under investigation that might impact the oil were the size and shape of the frying pan as well as the burner’s power output. Electric coil ranges — the most prevalent type of ranges involved with cooking fires — were used exclusively during the experiments, but Almand says the test methods, once established, could apply to gas and other types of ranges.
“The goal is to identify what would be an appropriate cooking event that could lead to a potential fire that can be done in a reproducible way and represents the most challenging conditions to a range of technologies out there,” says Gottuk, the project’s supervisor, adding that mitigation technologies themselves weren’t tested during this research. Hughes completed its analysis in June and anticipates issuing a report later this year.
Similar research is underway at Eastern Kentucky University (EKU). Funded by Vision 20/20, the project analyzes auto-ignition temperatures of nine fuels heated atop four types of stovetops, including one equipped with the Safe-T Element. Researchers characterized the heat output of six- and eight-inch pans placed on burners at low, medium, and high settings. Fuels were added to the pans, and thermocouples, or temperature gauges, were placed inside the pans and directly above the fuel to determine “the heat characterization being transmitted…and how it affected the top surface of the material being heated,” says the EKU researcher Corey Hanks. A report on the findings is anticipated later this year.
Another study by Underwriters Laboratories and the University of Maryland aims to pinpoint predictors that could prevent flaming stovetop fires. Oxygen and gas concentrations at the stove’s burner, the stove’s hood, and kitchen ceiling levels were analyzed during 11 scenarios, including frying bacon and cooking ground beef. The research, says Almand, might prompt specific types of smoke detection devices near the stove that alarm when pre-ignition conditions are present.
Other countries have already incorporated certain types of mitigation technology. Some stoves in Japan, for example, require temperature-regulating devices that cut power to the cooking surface if it approaches specified ignition temperatures, says NIST’s Madrzykowski.
Similar code-driven requirements, supported by standardized testing, may appear in the United States in the future, Madrzykowski says. “Once a standardized test for a cooking implement is available, you may see something from the codes and standards arena, where all rental housing needs to have a fire-resistant stove, or some states and localities saying, ‘All homes need to meet this standard,’” he says. “That’s down the road — it’s certainly not happening in the next three to five years — but there’s certainly potential for that.”
Meanwhile, NFPA plans to expand its cooking-fire advocacy efforts that are designed to mirror its successful push for residential smoke alarm use and fire-safe cigarette legislation adoption, says Lorraine Carli, NFPA’s vice president of Communications.
“The other piece we’ve identified — other than the research need and continuing public education push — is better collaboration with other organizations addressing the cooking-fire problem,” says Carli. “A lot of the issues related to cooking fires and cooking-fire mitigation that are bubbling up here at NFPA are bubbling up elsewhere.”
Fred Durso, Jr. is staff writer for NFPA Journal.
- Of the more than 157,000 estimated home structure fires reported annually during the period 2006–2010, cooking caused 42 percent of the fires, 38 percent of injuries, and 15 percent of deaths.
- Unattended cooking was the leading contributing factor to these fires and fire deaths.
- Ranges, with or without ovens, accounted for the majority of home cooking fire incidents.
- Three of every five non-fatal home cooking fire injuries occurred when the victims tried fighting the fire.
- Frying poses the greatest fire risk.
Source: NFPA’s “Home Fires Involving Cooking Equipment” report.
A primer on some of the technologies designed to reduce cooking fires
Come On Baby, Mitigate My Fire
A lack of standardization for evaluating cooking fire technologies hasn’t stopped manufacturers from developing products for commercial and consumer use. Here’s a selection of devices currently on the market, taken from the Fire Protection Research Foundation report, “Home Cooking Fire Mitigation: Technology Assessment.”
A motion-sensing device determines if a cook is present when an electric stove burner is on. If there’s no movement, the sensor begins a countdown and sends visible and audible warnings after a determined amount of time. The power is cut off to the stove if the cook doesn’t respond to the alarms. Another motion-sensing device automatically shuts off a stovetop when the cook isn’t present.
Contact burner temperature and sensor control
This device includes a cast-iron plate that is placed over electric coil burners. Another component placed inside the stove regulates the plate’s temperature so it doesn’t surpass a specified value, thus preventing the ignition of food and other products from unattended or careless cooking.
Over-range temperature sensor with burner control
A sensor is mounted to an exhaust hood and monitors high temperatures that could mean overheating or that burners have been left on. Once an alarm sounds, another device cuts electricity to the stove’s burner.
Smoke detection with burner control
Equipped with either a photoelectric smoke alarm or a combination photoelectric/ionization alarm, this product includes an electrical control device that cuts off a stove’s electricity when the alarms are activated. The electrical control mechanism can be configured to use other alarm devices, including gas, heat, and other smoke detection devices.
Unlike gas burners and electric coils, induction cooktops use a magnetic field that produces an electric current to heat cast iron or stainless steel cookware. Only the cookware — not the cooking surface — gets hot, reducing the potential of the ignition of nearby materials. Moreover, burners cannot be accidently turned on, since the stovetop operates only when a piece of ferrous cookware is placed atop the burner.
Kitchen suppression system
Due to their size and expense, these systems are typically intended for commercial kitchens and may include exhaust hoods, temperature detectors, chemical or water suppression systems, and the ability to cut off a burner’s gas flow or electric current. Home versions do exist, however, and use a heat-activated device attached to a vent hood that discharges a sodium bicarbonate extinguishing agent.
— Fred Durso, Jr.