It’s a warm summer day in 1985. You’re part of an engine company in New York City. Just before dinner, you get dispatched to a single family dwelling fire. On arrival, flames are pouring out of every window – a fully involved working fire.
It’s a cool fall afternoon in 2012, and you’re part of the same engine company in New York City. At 1712hrs, Manhattan assigns you to a single family dwelling fire. As your company pulls up to the fully involved home, four minutes have transpired since the ring down. The home is fully involved.
While these structure fires may appear to be the same, in fact they are not. Firefighting has changed. While building materials have evolved to reduce fire dangers, furniture has gone in the other direction. The interior of a home is now a cocktail of fuel and material that change the dynamic of firefighting.
In 1985, based on significant data from across the country, the average time frame for an interior flashover (near simultaneous ignition of items in an enclosed space) would have been 18 – 22 minutes.
In 2012, that time has been reduced to four to five minutes.
Heat can increase from several hundred degrees to more than 1,500 degrees in less than 15 seconds. In the 1980s, it might take a full minute to see similar heat readings.
In the 1980s, furniture in the typical home was made of wood, metal, and glass. Today, plastic dominates, as do wood composites. Ever bought anything from Ikea?
How do these changes affect firefighters and firefighting tactics?
There’s a lot to consider. One immediately apparent change is how fresh air affects a fire. Traditionally, as a fire grows in a building interior, the buildup of heat and gas creates visibility and access challenges for firefighters. To aid in interior firefighting, truck companies would open the building exterior – typically a roof to allow heat and gas to escape. As visibility increased and heat was reduced, firefighters could gain the upper hand via a variety of interior fire attack tactics.
Today, the impact of fresh air is different. Initial studies are showing that today’s furniture gains headway far more rapidly, but also as a result, tend to stall, due to the lack of oxygen. Now, when a truck company opens the roof, the fire gains a fresh lease on life and surges, complicating established fire attack tactics. This also increases the risk to firefighters.
FDNY is working with the National Institute of Standards and Technology (NIST), Underwriters Laboratories (UL) Preservation and Governor’s Island Preservation and Education Corporation (GIPEC) to gain new perspectives into the science of fire. The research team will conduct two weeks of tests, evaluating all of the aspects of interior fire growth and sustainability.
Considered to be one of the most extensive research suites contemplated for fire science, a wide array of technical measures will be incorporated, including heat-flux gauges, pressure sensors, bi-directional probes and thermal imaging cameras. Some of the sensors, like the heat gauges, were set up at different heights in each room, to test temperatures as various heights – does “get low and go” still make sense for civilians attempting to exit a building? What are the issues that could impact firefighters during interior fire attack?
Once the results have been collected an analyzed, we’ll share that information with you.