Education Matters – OFM report on issues surrounding the tragic fire in Listowel that claimed the lives of two Firefighters.

The investigation into the tragic fire in Listowel that claimed the lives of two firefighters is ongoing. However, the Office of the Fire Marshal (OFM) is releasing some information on the cause, origin and circumstances of this devastating fire.

On March 17th, contractors were repairing the roof of the building which led to the ignition of the interior combustible components of the roof structure.

Responding crews indicated that since there was an absence of significant smoke or flame in the building, they entered to confirm no one was inside and to investigate the source of the reported fire. While inside the building, a sudden collapse of the roof structure resulted in the deaths of two firefighters.

The investigation has determined that the building’s roof was constructed with lightweight engineered wood trusses.  The OFM wants to ensure the fire service is aware of the hazards associated with fighting a fire in a building with this type of construction. Under fire conditions, lightweight engineered wood and metal trusses are known to collapse very quickly and with little warning.

When arriving at a structure fire, incident commanders must conduct an initial size-up of the building and attempt to determine construction type. They should also determine to what extent the building may have been damaged by fire before initiating firefighting efforts. This information will assist the incident commander in making operational fire ground decisions.

It may be difficult for incident commanders or firefighters to identify lightweight engineered truss floor or roof construction upon arrival at a fire scene. If available, incident commanders should consider using a thermal imaging camera as part of the exterior size-up. Other strategies include being constantly aware of the time that has elapsed since the start of the fire, watching for signs of structural deterioration and using extreme caution when venting or opening concealed spaces. Firefighters should provide continuous feedback on changing fire conditions to the incident commander and should be trained in recognizing risk of fire exposure on lightweight engineered truss construction.

When the type of construction cannot be determined, responding crews should assume that lightweight engineered truss construction is present. Therefore, incident commanders should consider employing defensive fire attack strategies, particularly where no threat to human life exists. Firefighters should not be on or under lightweight engineered truss roofs or floors when the trusses have been exposed to fire.

If possible, gather and document information on buildings in the community and plan appropriate fire attack strategies for specific buildings. In addition, information on materials used for construction could be obtained from the local building department or from the building’s owner. Although crews will not likely be able to pre-fire plan every building in their community, it is recommended to target specific buildings and to visit new subdivisions to determine the type of construction. This information should be readily available to responding crews.

In addition, it is important for incident commanders and firefighters to be trained on construction types and associated fire behaviour. Responding crews should have a good knowledge of lightweight engineered truss construction and procedures to be followed when fighting a fire involving this construction.

Although lightweight engineered truss construction has been used for approximately 50 years, it has become more popular in recent years.

The OFM has distributed materials to inform the fire service about the hazards associated with this construction. For more information please see the links below and the attachments. For additional questions or to arrange a presentation in your area, contact Ed Gulbinas, Manager of Applied Research, OFM at 416 325-3240 or email ed.gulbinas@ontario.ca.

The OFM’s investigation is continuing. Through further research and analysis of the sequence of events surrounding this fire, the OFM will in the future provide the fire service with additional information and increased knowledge to safely respond to similar fires.

For more information see the following links and attachments:

“Fire Performance of Solid Wood and Engineered Floor Joists” – OFM Messenger article, December/January 2009 Issue (see attached)

OFM Communiqué 2007-06 (Feb. 2007)  [DEAD LINK]

“Engineered Lightweight Wood Framing Systems” – OFM Messenger article, Summer 1998 Issue (see attached)

“Fire Performance of Houses. Phase 1. Study of Unprotected Floor Assemblies in Basement Fire Scenarios. Summary Report.” – NRC [DEAD LINK]

“Preventing Injuries and Deaths of Fire Fighters due to Truss System Failures” – The National Institute for Occupational Health and Safety Summary Alert