BASEMENT FIRES

Introduction From a firefighting standpoint, basement/cellar fires are one of the

most dangerous and challenging fires encountered inside a building.

They have limited ingress/egress, limited ventilation, and drainage problems for the attack water.

Interior suppression crews face significant heat during ingress to the seat of the fire while operating in an environment where minimal ventilation causes retention of that heat. This heat in basement fires tends to radiate back on the attack crews.

In addition to being hot, challenging, abusive-type fires, basement fires should be considered as possible hazmat incidents. Basements are notorious for being the long-term storage place for not only normal combustible storage items, but for paints, solvents, varnishes, insecticides and cleaning solvents.

Intro (cont.) It is also the main area of the structure

where water heaters, dryers and HVAC units are stored and generally fueled by natural gas, propane or fuel oil. Because of this, it might be wise to consider some type of gross decontamination for interior attack crews after a basement fire.

Significant Impacts All of these problems cause significant

impacts on the ability to deliver fire attack tactics during the evolution of a basement fire. These additional impacts include fire suppression tactics, search and rescue, ventilation, and rapid intervention.

Significant Impacts (cont.) Tactics for fighting basement fires begins

with responding. If there are numerous reports from interior occupants, let this drive your initial fire ground operations. Get that water supply established as rapidly as possible. Remember that basement fires are generally self-contained until they generate enough heat and pressure to cause window failures in those structures that have basement windows.

Significant Impacts (cont.) Light smoke coming from the interior of

the structure should lead you to believe that a much larger volume of smoke awaits you in the basement. A rapid size-up is critical to identifying the fire location in the basement as well as locating alternate entrance and exit points.

Significant Impacts (cont.) Remember that a large majority of basements are

unfinished, which exposes the structural floor joists and their support structures to flame contact. Newer structures with engineered floor supports or “silent floor systems” will burn and fail quickly. Consider the possibility of extension of the fire into the support structure of the floor you are operating on.

The first attack crew will be challenged by having to position themselves at the hottest area at the top of the stairs into the basement area. A second line should be established at the top of the stairwell to protect the structural integrity of the stairs.

Steam Burns Nozzle selection should consist of a solid

stream nozzle of the straight stream setting on the fog nozzle. With minimal ventilation, more water surface area will cause steam generation and steam burns to the attack crews. Rapid establishment of ventilation will be the best tactic to reduce the heat and smoke from the fire, which will greatly enhance access and supervision for the engine crew.

Steam Burns (cont.) Initial attack crews must perform a rapid

risk/benefit analysis regarding the initial attack strategy. If an interior attack is selected, the attack crew must move to the basement entry point quickly and down the stairs as rapidly as possible to reduce the punishment from the heat and smoke while moving through the “chimney” and into the basement.

Steam Burns (cont.) The initial commander

should have a strong accountability process and establish a formal RIT as soon as possible. An RIT should be in place before an initial fire attack.

Steam Burns (cont.) Keep in mind that an open basement

door will also allow for rapid fire/heat/smoke spread throughout the first floor while the attack occurs in the basement. Keep a strong grasp on the total timeline of interior firefighting.

Steam Burns (cont.) If dealing with a truss or engineered

floor system, keep your interior attack times to a minimum – 15 minutes at the most! If interior attack teams are not making progress on the fire within five minutes of arrival, consider making a switch to a defensive attack.

Construction

Underwriters Laboratory Study UL did a study with 2 separate

basement floor assemblies: #1 – a 2 x 10 wood joist floor with

hardwoods on top (common to older homes).

#2 – a lightweight floor assembly (new homes) with carpet on a subfloor.

UL study (cont.) Both of the floors had no ceiling assembly so it

would resemble the unfinished basement, which simulated the working fire directly under the floor.

For the entire duration of the test a T.I.C. was aimed at the 1st floor, which would be similar to us walking through the front door.

They placed 2 firefighters in full PPE, one standing and one crawling directly above the basement, on top of the two different floor assemblies.

UL study (cont.) Here are the results: for the 2 x 10 floor-1:45 minutes in : 845 degrees in basement / 74 degrees on 1st floor-5 minutes in : 1383 degrees in the basement / 75 degrees on 1st floor-8.5 minutes in : 1296 degrees in the basement / 86 degrees on 1st floor• It should be notes that the nail heads used to nail the floor onto the

subfloor are the only items showing a heat signature.• The floor collapsed sending the 2 FF’s into the basement at

approximately 19 minutes from ignition.

UL study (cont.) Here are the results: Lightweight floor-1:45 minutes in: 1196 in basement / 71 degrees on 1st floor-3:30 minutes in: 1330 in basement / 73 degrees on 1st floor-5:30 minutes in: significant 1st floor deflection and smoke emitting-5:55 minutes in: 1286 degrees in basement / 85 degrees 1st floor* The floor catastrophically collapsed sending 2 FF’s to the basement at 5:55 minutes from ignition.

What Does the UL Study Teach Us?

TIC’s – Are only a tool to aid us. We must not allow them to take us away from employing those vital basic firefighting skills.

The TIC only picks up surface temperatures in the room and not a 1300 degree fire in the basement below. If you sweep the floor with the line before you went in, the temperature that the TIC is reading is the surface temp of that wet carpet or hardwood floor.

What Does the UL Study Teach US?

Time: While we know that time is never really on out side, we now have actual data to support the belief that when we go to fires in older homes that we do have longer to fight fire. Conversely, when we go to fires in newer homes that have lightweight components, we now know that window of time is much smaller.

Size-Up

Tactics Your tactics are going to be dependent

upon what your operational guidelines are and based on what you find during your size-up. Don’t get caught up in a “cookie cutter” mentality. If you feel that something different needs to be done to be successful, then do it. Think and act. Use your experience and best practices.

Tactics Don’t rely totally on a TIC to determine if

you have fire below you. Studies show that the camera will only read the ambient temperature of the room and materials. With fire below you, the subfloor, padding and carpet can show much lower temperatures than what actually exists.

Tactics We have a responsibility to search for

victims whenever there is any question about the occupancy. In some instances, it may be more appropriate to make access to the basement from an exterior access to directly attack the seat of the fire while a search crew makes entry on the floor above.

Tactics This must be determined from the size-up,

and communication is key. This simultaneously puts water on the fire, improving conditions while victims are being searched for.

Sounding floors is paramount, but with todays building materials, you have little to no notice prior to a collapse. Have a backup crew ready at the door for the protection of the first crew.

Tactics Heading down the stairs will be challenging.

It will be hot at the top of the stairs, but you must be cautiously quick getting down them. Feet first, one foot at a time sounding the stairs and feeling for stability. Have the hand line ready to knock back any fire that may want to vent up the stairwell. At the bottom, use the same skills as you would for any other fire. However, speed is your friend here. Fire the fire and get it knocked down!

Final Remarks These thoughts and considerations are

merely snapshots of what to look for on a basement fire. This is in no way the ultimate or final list of how to handle all basement fires.