The Massachusetts Division of Fire Safety (DFS) is investigating the causes of three house fires that were ignited while insulation contractors were installing spray polyurethane foam.
According to Tim Rodrique, the director of the DFS, investigators suspect that the fires were caused by the exothermic reaction that results from the mixing of the two chemicals used to make spray foam.
A $5 million house is destroyed
One of the fires destroyed a $5 million home on the exclusive Penzance Point peninsula in Woods Hole on February 10, 2011.
The house was being renovated at the time. According to the Cape Cod Times, “firefighters were somewhat stymied due to spray-on foam insulation. … Similar insulation has proven deadly in the past. In 2008, Robert Cowhey of Springfield was spraying soy-based foam insulation in the attic of a North Falmouth home. The chemicals were located in a truck outside the home in two 50-gallon tanks, but somehow they ignited and Cowhey died in the ensuing fire.”
Robert Cowhey, the victim who died in the North Falmouth fire, worked for Green Mountain Insulation of White River Junction, Vermont. Cowhey was installing SoyTherm50 spray foam insulation when the fire broke out.
According to the Cape Cod Times, “The first sign of trouble came when a co-worker smelled a burning odor and noticed smoke billowing in the fireplace on the floor beneath the attic. He and another worker tried to reach Cowhey and put out the fire with an extinguisher. The two were stymied by the intense heat and smoke, however.”
According to an OSHA report on the North Falmouth fire, “The company was spraying expanding foam insulation in the attic of a single-family, two-story house that was undergoing renovations. The spray foam properties were such that it could generate sufficient heat immediately following its application to cause spontaneous combustion. Among the chemicals being used were diisocyanate; flouroethane and lead naphthenate. There was no fire extinguisher in the attic space during the spraying process and no rescue plan in the event of a medical emergency. The employer had not developed or implemented a fire protection or prevention plan. Access to the attic was via a 3’ wide by 6’ long hole in the second floor ceiling. The attic was not ventilated. A flash fire occurred in the attic in which an employee died.”
OSHA further notes that “the products used were SoyTherm 50 and SoyTherm 100 and are diphenylmethane diisocyanate (MDI) based. A technical bulletin issued in November of 1993 by the Polyurethane Division of the Society of the Plastics Industry, Incorporated located in New York City warns of the spontaneous combustibility of the material. SoyTherm is known in the industry as an open cell foam insulation.”
A warning is issued to all Massachusetts fire departments
On July 1, 2011, Stephen D. Coan, the Massachusetts State Fire Marshal, issued a memorandum to the heads of every fire department in the state. The memo notes, “Recently, the Department of Fire Services, Division of Fire Safety, has become aware of a number of fires involving commercially available spray-on foam insulation. At least 3 fires, one being a fatal fire, are believed to have been started during the application of spray foam insulation, and currently remain under investigation. …
“Information gathered by the Division of Fire Safety from different manufacturers indicate that there are several possible scenarios that could lead to a heat build-up, and a possible fire scenario. These are: improper application techniques (excessive thickness, or spraying new material into the already applied rising foam) and/or improper mixtures of the chemicals at the application nozzle.
“Based upon this information, the Division of Fire Safety is recommending that you work with your building officials to determine if such applications are taking place within your community and, if so, to also make contractors in your communities aware of this potential fire hazard and encourage that they follow application instructions accurately.”
A similar case in Quebec
In a case similar to the Massachusetts fires, a net-zero-energy house in Hudson, Quebec burned to the ground on May 25, 2010. The Quebec fire erupted a short time after workers finished insulating the home with spray-foam insulation. In all of these cases, investigators assume that installers applied the spray foam too thickly, thereby trapping the heat generated by the chemical reaction that creates the foam.