Firelines: November 2014
By Dave Balding
By Dave Balding
Change is something progressive fire-service leaders must embrace to help keep firefighters safe and do the best job they can to protect their communities. It’s time; time to change the strategies and tactics used to fight fires in today’s buildings, loaded with highly combustible content.
We know that fires are hotter and burn faster than ever before. So why do we use techniques taught 25 years ago to fight fires in buildings made of – and full of – different and more combustible materials?
Furnishings made of composite materials, coupled with elements of modern, lightweight building construction are game changers. Response times were once predicated on the estimated burn time a compartment could withstand before the effects of fire made it untenable for occupants and the building’s structural integrity. Today’s quicker, hotter fires have an enormous impact on responders.
Using yesterday’s response tactics on today’s buildings – according to significant research and field trials from organizations such as the National Institute for Science and Technology and Underwriters’ Laboratories – is not only ineffective, it is also dangerous.
The standard approach of entering through the front door using an offensive (interior) attack is a perfect example: buildings and contents now reach flashover potential much faster than they did a generation ago – up to eight times faster. When firefighters arrive at what was once considered a routine fire, they now see a lot of black smoke – flammable products of combustion. This fire may well be vent driven by the time firefighters are on scene. Firefighters must now be aware of the combustion air that’s allowed into the structure, which may come from uncontrolled venting due to broken windows, or failure to manage entry points after the suppression crew gained entry.
Perhaps the biggest change in the way firefighters think of and manage structure fires is awareness and management of flow path. Simply put, the flow path is the movement of heat, smoke and fire gasses to areas of lower pressure. Knowing and controlling the flow path accomplishes two goals; it improves occupant survivability and it helps direct the fire away from unaffected parts of the structure.
We now know the old belief that an exterior attack pushes fire further into a building isn’t true. In fact, a transitional attack has been proven to be a great way to buy a little time for interior-suppression crews in this hostile environment. Essentially, a transitional attack is early application of water through an existing opening using a straight stream into the fire compartment. This cools flammable products of combustion in the room, buying a little time for the attack crew, and avoiding flashover as responders introduce air to the fire upon entry.
The pneumonic SLICE-RS has been coined to provide some guidance with these concepts.
Size-up: this starts pre-incident and during an alarm includes, as always, the establishment of incident command, a 360-degree scene assessment, and much more.
Locate the fire: determine exactly where in the building the fire is located. This information will drive decisions made in the next step.
Isolate and control the flow path: restricting openings such as doors to unaffected areas is the simplest way to manage the flow path.
Cool the fire: direct a straight or solid stream into the fire compartment for a few seconds from the exterior of the building before crews enter. This cools the superheated fire gasses.
Extinguish the fire: a well-co-ordinated attack with ventilation is critical as the time between ventilation and flashover in today’s fires is much shorter than in older buildings with familiar fuels.
Rescue: information gathered during size-up will determine where rescue fits into the process; confirmed or possible occupants makes rescue a higher priority.
Salvage: this step, like rescue, occurs at anytime during the response. It can be achieved with salvage covers or simply by closing doors during operations.
As fuel loads, structures and the fires within them have changed, so must we in the fire service. The adage “we’ve always done it that way” has no place in fire fighting. I am not suggesting that everything the fire service knew and practised has gone by the wayside; in fact, many aspects of SLICE-RS should be very familiar to firefighters. This is simply a guide for first-in engine companies that reflects today’s techniques for today’s fires. Firefighters must keep doing what works, discard what doesn’t work, and be prepared to embrace new practices that are backed up by fire science and research.
Dave Balding, a 29-year veteran of the fire service, is the fire chief and emergency co-ordinator for the Village of Fraser Lake in British Columbia’s Central Interior. Contact Dave at firstname.lastname@example.org and follow him on Twitter at @FraserLakeFire