Photos by author
Previously we looked at the firefighting tactic of the blitz attack, using our deck-mounted monitor or ground monitor to dump all our onboard water at once onto the fire to quickly knock down the fire and then initiating an interior attack to finish it off. This tactic looked at the possibility of limited personnel or resources arriving on scene with a significant fire showing or being produced.
This month I want us to consider another tactic called the transitional fire attack. This is a relatively new tactic by name, but some of the practices have been around for many years. This tactic has gained some ground in the last number of years because of the studies conducted by the National Institute of Standards and Technology (NIST) and Underwriters Laboratories (UL) at Governor’s Island and in Chicago. The studies were conducted to show the science behind our modern-day fires, and firefighters need to adapt a newer way to tackle them.
The one main point that everybody needs to remember and take away with them concerning this study and this tactic is this–life safety or rescue is still our number one priority! This tactic does not remove this fireground priority and allows for a rescue or rescues to be made with intensive fire or heat showing in or near the location of the occupants. Remember, rescue is our number one concern and priority!
This tactic does not replace the interior attack, nor does it reassign a fire department so that it becomes a defensive operational unit only. Many may have misconstrued this while reading the data and the report from NIST/UL studies. The exact opposite is true.
So why the transitional attack? Is it because of our fires are hotter than they were 20 years ago? Are they hotter now than they were 20 years ago? The short answer to this question is NO—fires are not hotter today than they were 20 years ago. So, what has changed?
The heat release rate has changed. We are witnessing and experiencing fires that produce a much higher release of energy and reach extreme temperatures much quicker than before. This is due to the growing demand of petrochemicals in our everyday products and furnishings. They are contributing to a higher and quicker heat release rate (HRR).
So how do we overcome this? The transitional fire attack is one of those ways to help overcome the quick and high buildup of the HRR. We need to look at fires as gpms or lpms versus HRR and not British Thermal Units (BTUs). The latter look at temperature and not the release of heat. We are fighting fires that require enough water to overcome the HRR that is present within the compartment.
RELATED FIREFIGHTER TRAINING
The transitional fire attack works best when we observe a self-venting fire from a window and we have the report of occupants still inside or we need to go in to conduct a primary search as well as suppress the fire. The key factor for this tactic to work is the size up or 360° walkaround. It is imperative that the first-arriving officer with the first-arriving unit does a complete walk around to size up the fire and the building.
The immediate question that has to be answered by the 360 is this–is the fire vent limited (contained to the interior) or self-venting? As you can see in photo 1, the fire is self-venting–it is not contained to the interior. This situation would allow for a transitional fire attack.
Once this decision has been made, the attack line is pulled off, flaked out, charged, and then readied for water application from the outside. This is where the firefighter will direct the nozzle on a straight stream pattern or with a smooth bore nozzle, a stream of water directly up to the ceiling on the room to create a sprinkler head discharge within that room, as seen in photo 2.
This stream of water needs to be directed up to the ceiling directly above the fire and static in motion for about 10 to 20 seconds. We do not want the stream of water to be moving in a circle fashion or up and down as we regularly do – it must stay static like a sprinkler head. By doing this we are not blocking the vent opening of the window, allowing the steam and hot gases to flow out–there is still going to be a bi-directional flow path established at that window working for us and not against us.
Once firefighters have applied water for about 10 -20 seconds, we then make our way in to aggressively suppress the fire from the interior. This is where we can make the rescue as well as suppress the fire. The NIST/UL studies have shown that the temperature reduction gained by doing this is significant, so much so that occupants near the fire room, in the hallway, in other rooms, on another floor are going to experience a temperature drop of about 50 percent or more. This reduction in temperature will help with their survival and with members on the attack line making their way in to suppress the remaining fire.
There are two ways to approach this tactic: use the same hoseline for the exterior water application and interior attack or use two separate hoselines. One hoseline is used for the exterior water application and the other hoseline is used for the interior attack. Depending on the size of the building and the location of the fire, his may cut down the time it takes to move the line from the outside to the inside.
Mark van der Feyst has been in the fire service since 1999 and is a full-time firefighter. He is an international instructor teaching in Canada, the United States, and India, and at FDIC International. He is also the lead author of Residential Fire Rescue (Fire Engineering Books & Video).
MORE MARK VAN DER FEYST