Extrication Zone: Large Vehicle Fire Operations


It’s a warm July weekday afternoon in northwest Louisiana when the portable squawks: “Webster Parish Fire District 7, respond to Interstate 20, MM42 for a tractor trailer on fire. Multiple calls indicate both the cab and the load may be involved at this time.”

For many departments, especially smaller career, combination, and volunteer agencies, a response to potential large vehicle fire operations (LVFO) can pose a myriad of challenges. These challenges can range from resources and apparatus, especially tankers, to insufficient personnel levels and the associated training required to effectively extinguish and manage the event.

I am a member of two adjoining fire districts, roughly 20 miles east of Shreveport, Louisiana. This is a challenge that either one of them—one a combination department and one a volunteer department—could face at any time. Combined, they cover more than 26 miles of Interstate 20, the major east-west truck route through the mid-south. In addition to I-20, the volunteer department, Webster Parish Fire District 7, which operates with 17 members from five stations covering 72 square miles, also covers a major truck north-south route through rural Webster Parish as well as two busy truck stops. The combination department, Bossier Parish Fire District 1, which operates with two administrative employees, six shift employees, and up to 80 volunteers covering almost 200 square miles from seven stations, is also responsible for providing fire protection to Camp Minden, a Louisiana National Guard maintenance and administration facility. The former army ammunition plant also houses the Regional Training Institute, a training facility for National Guard heavy truck drivers, and uses several types of military over-the-road transport vehicles.

Although the combination department has periods of reduced volunteer staffing, we generally will have an initial response level of at least 12 to 15 members during the day and 20 or more during the evening hours for working incidents. Because of an excellent volunteer response, we generally have very few issues with deploying and operating multiple 1¾-inch handlines and performing other needed functions at most large incidents, including large vehicle fires. In addition, there is rapid access to mutual aid from the bordering city of almost 90,000 and smaller single-station departments to the east.

(1) Members of the Haughton (LA) Fire Department operate two 1¾-inch lines on a training fire using a school bus loaded with Class A fuels.
(1) Members of the Haughton (LA) Fire Department operate two 1¾-inch lines on a training fire using a school bus loaded with Class A fuels. The fire was knocked down prior to interior operations with a 2½-inch line equipped with a 7⁄8-inch smooth-bore tip. (Photos by author.)

The problems associated with LVFO are significantly more pronounced at my volunteer agency, since we operate with significantly fewer personnel. After attending the Fire Department Instructors Conference (FDIC) in 2011, we decided that the response to our limited personnel problem at structure fires would be to implement a transitional attack approach. We developed and implemented procedures and trained members on the use of a 2½-inch line or an apparatus-mounted master stream as the initial line, depending on the structure type, fire conditions, and staffing for working incidents beyond a single room. We saw this shift in tactics as a method of applying a significant amount of water quickly to the seat of the fire with one member before automatic mutual aid from the neighboring small city arrived.

After training on this approach to structure fires, we discovered that it could also have significant value at large vehicle fires where, again, we were looking for a way to apply water rapidly with our minimum staffing.

I’ll begin by saying that not all large vehicle fires represent significant challenges that require operational changes from the “traditional” single-attack-line approach. Everyday engine fires, brake fires, tire fires, and even nonsleeper cab fires can still be handled effectively and safely using traditional single-handline evolutions.

The focus of this article is on fires that involve a significant portion of today’s large vehicles, which are defined as 18-wheelers with large sleeper extensions, tractor trailers, enclosed multivehicle car transporters, buses, recreational vehicles, and large travel trailers. Certainly, other vehicles such as large tandem axle box trucks, construction equipment, and larger military vehicles can be placed in this category as well. These larger vehicles require a new approach that involves the delivery of large amounts of water during the initial stage of fire attack. This approach increases operational effectiveness and also has a significant impact on member safety.

Major Challenges

As senior members, training officers, company officers, and members of the command staff, it is critical that we understand some of the hazards associated with LVFO, as they can influence operational and training-related decisions. Some of the issues posed by these vehicles, such as vehicle construction, are beyond our control, but many of the problems we face in handling large vehicle fires can be solved with new techniques and training.

Modern LVFO generally involve the following significant challenges.

Large Vehicle Construction and Materials

Like structure fires and passenger vehicle fires, large vehicle fires have undergone a transformation that has spurred dramatic and dangerous changes in fire behavior. The changes have occurred in great part because of the significant increase in hydrocarbon-based solid fuels now being used to construct these vehicles. Increased British thermal unit (Btu) production, increased heat release rates, and explosive fire growth have created hotter, more intense fires that easily overwhelm the traditional handline-based initial fire attack. This change in fire behavior is no surprise to those who have been responding to these incidents over the past few years and have witnessed a doubling of the heat being produced in a fraction of the time.

To reduce weight and increase fuel mileage on large vehicles, there has been a transition from steel and metal exterior skins to lightweight plastics. These materials contribute to the increased fire intensity we are experiencing in today’s large vehicle fires.

In addition, the interiors of most large vehicles have had an increase in the amount of highly combustible furnishings. Take a quick look at the interior finish of any tour bus, recreational vehicle, or over-the-road sleeper cab. It’s easy to see why large vehicle fire behavior has undergone significant change over the past several years. The increase in the quantity of the hydrocarbon-based interior furnishings, in tandem with the exterior skin changes, poses significant challenges to any small department’s ability to deliver sufficient water to match the Btus being produced.

(2) Large vehicles, such as this moving van loaded with hydrocarbon-based solid fuels, can and will pose significant extinguishment challenges.
(2) Large vehicles, such as this moving van loaded with hydrocarbon-based solid fuels, can and will pose significant extinguishment challenges.

Not only has the exterior package transitioned, but overall the size of most large vehicles has significantly increased in the past 20 years. Although the size of today’s 18-wheelers, especially those equipped with the much larger sleeper cabs compared to legacy vehicles, dwarfs many of the older vehicles, the increase in vehicle size has been most dramatic with recreational vehicles (RVs) and travel trailers. It’s fair to say that even one of today’s smaller RVs would be fairly sizable when compared with the RVs of 20 years ago. Today’s tandem-axle monsters built on bus and large commercial truck chassis pose fire suppression challenges equal to or, in some cases, greater than those of a well-furnished single-wide mobile home, especially when the flammability of the vehicle’s exterior skin, the liquid fuel load, and the propane tank’s capacity are considered. The fire load increases even more when the vehicle is towing a vehicle, boat, or storage trailer that may also be involved.

Some departments have recognized and adjusted to this new reality, but many others have not and still attempt to use tactics that are more applicable to much smaller models.

Cargos and Loads

Many view the emergence of the big-box store as the primary drivers of the transition to hydrocarbon-based fuels and today’s supercharged structural fire behavior. Obviously, those goods have to be transported to the retail outlets, and, in a similar fashion, this trend has also impacted fires in large vehicles. Not only have we seen this transition in the trucks delivering to big-box stores such as Target and Walmart, but we have seen similar changes in the loads being delivered to mid-size neighborhood discount “Dollar” stores and big-box drug stores.

The transition to hydrocarbon-based residential furniture has also impacted the intensity and speed of the fires found in 18-wheeler moving vans hauling home furnishings. These trailers can easily contain the solid fuel load needed to comfortably furnish a double-wide mobile home or, in some cases, a large site-built structure in a much more compact area.

Auto-carriers, especially those with dual levels, post a most challenging fire load. These trailers can range from the open-rack and soft-sided “Waggoners” style trailers transporting anywhere from eight to 14 vehicles all the way to multivehicle, enclosed carriers transporting high-end sports cars and NASCAR racing trailers.

The multiple “fuel packages” carried by these trailers can easily overwhelm initial resources, especially if exposures are threatened. Additionally, the steel supporting the upper level of any dual-level auto-trailer can weaken and fail when exposed to the high levels of heat created by today’s vehicles, posing significant collapse issues. These dual-level trailers also can create fire access issues to vehicles on the upper level; advanced laddering, hose-handling skills, and increased personnel will be needed to maintain firefighter safety during fire attack operations.

Enclosed single-level racing trailers heading to local or regional race tracks not only may carry a spare or a second car, but they also may carry all the resources needed for the race day including multiple sets of tires, spare body parts, and even high-octane racing fuel.

Trailers carrying natural loads such as sawdust, wood chips, mulch, square or round hay bales, and other related materials can also create significant operational challenges. Fires in these vehicles can generate the need for significant amounts of water, Class A foam, heavy equipment, rehabilitation resources, and relief personnel for extended overhaul operations.

Trailers carrying large amounts of rubber, such as tires, may necessitate the need for additional amounts of Class B foam, specialized hazardous materials resources, and water runoff control operations. These operations may involve significant law enforcement resources for limited evacuations and traffic diversions. They can also have significant environmental impacts and may require air- and water-monitoring capabilities as well as the involvement of state and possibly federal environmental regulatory agencies.

The same issues can also arise with fires in large garbage trucks, which potentially can pose similar overhaul, hazardous materials, runoff, and decontamination issues.

For departments encountering specialized loads and cargos, training should be held to familiarize members with any unique characteristics of the materials and transport vehicles. As some of those materials may require specialized tactics, training, and resources, those needs should be identified before an incident occurs.

One final consideration when discussing loads is the increased size of the diesel tanks found on most over-the-road vehicles. It’s not uncommon to find twin saddle tanks of 100 gallons each, which create the potential for a significant running fuel fire should one or both of the tanks or fuel lines rupture. Responding departments must have the capability to deal with this issue or, at a minimum, know where to get the resources should this occur.

In addition to large diesel tanks, most recreational vehicles and travel trailers contain large propane tanks. You may also find pressurized tanks on large vehicles of all types that are powered by compressed natural gas (CNG) or liquefied petroleum gas (LPG); they are becoming much more common, especially in urban areas. These tanks may be exposed but more likely would be contained within a compartment on the vehicle. Anytime an RV, a trailer, or any other vehicle containing a pressurized gas is well-involved, the incident commander should locate the relief valve and access and cool the tank with a dedicated handline early in the incident.

(3) Tire fires, such as the one pictured here, can still be effectively attacked and managed with a single 1¾- or two-inch hoseline, especially when Class A foam is added.
(3) Tire fires, such as the one pictured here, can still be effectively attacked and managed with a single 1¾- or two-inch hoseline, especially when Class A foam is added.

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