The state of Texas this year is enduring one of the worst fire seasons on record. Yet to a large extent we haven’t embraced fully the reality that these fires require different tactics, different training and different apparatus. While we can use the typical Type-6 brush truck and the Type-1 structure engine, neither really offer the total package. The ideal wildland-urban-interface engine continues to be elusive.

So what’s a department to do? The only solid answer is that the answer for my department may not be the answer for yours. Here’s why.

For starters, a WUI engine should be compact and maneuverable, should have a higher ground clearance than other apparatus, and should be strong enough to endure the abuse it will receive. And, if it might travel more than a hundred miles very more than occasionally, it also ought to have a few creature comforts.

The truck must be able to carry enough water to sustain an initial attack on a wildland fire and protect typical residential structures. Five-hundred gallons is the norm, and while more is better, there will be a trade-off in size, weight, maneuverability and cost. The amount of water any chassis safely can handle is limited by its gross vehicle weight rating. Far too often many of us ignore the GVWR, and I’ve seen countless “brush trucks” grossly overloaded. We can’t always make a silk purse out of a sow’s ear.

A Class A foam system capable of long periods of effective performance is critical. Ideally it would have compressed-air foam, or at least the ability to produce high-pressure Class A foam (i.e., a 1% foam solution at 250 psi via a 1-inch hose line using a medium expansion nozzle). One demonstration done by Rosenbauer showed that high-pressure Class A foam was as effective as CAFS. My personal experience is that 250 psi is the minimum pressure needed to create thicker, “shaving cream–like” Class A foam. Many suggest an initial quick coat of soapy foam followed by a thicker, longer-lasting second coat.

Even after all the years of positive experience and research supporting the use of foam, many in the fire service still are reluctant to add this substance to water. But the doubters should note that 500 gallons of water combined with Class A foam multiplies the former’s effectiveness; indeed, in some instances, Class A foam can more than double the effectiveness of water alone. It continues to amaze me that everyone who considers such a notion to be blasphemy is more than likely using modern technology in every other aspect of their lives, but for some reason they just can’t get a grip on using Class A foam, much less CAFS on all class A fires. Not only should it be used, it should be used all the time.

Get Hosed

Because WUI fires often go on for hours and commonly days, it’s imperative to have sufficient quantities of 1-inch and 1.5-inch lightweight forestry hose, at least 500 feet of each. A couple hundred feet of lightweight, single-jacket 2.5-inch rack hose also is nice to have if hydrants are present, though in many interface scenarios we try to avoid getting tied to a hydrant. I’ve watched firefighters use 5-inch hose and 1.75-inch structure lines to fight wildland fires. Often they drag these lines for hundreds of feet only to squirt less than 50 gallons to suppress the flames. After hours and hours of this, they’re beat. The idea is to work smarter, not harder.

Discharges off the rear are pretty important, especially when the truck has to “cut and run.” At the first big fire (Cerro Grande) to hit Los Alamos, N.M., in 2000, I saw a large amount of structure hose and 4-inch and 5-inch supply hose that was cut and lying in the streets. The reason was that engine after engine tied to a hydrant and then had to make a hasty escape when the hydrants failed and the flames kept coming. Believe me, it’s much easier and far less expensive to pick up or leave 200 feet of forestry hose and a $25 plastic, dual-gallon forestry nozzle than the 200 feet of rubber-lined double-jacketed structure hose and a nozzle costing hundreds of dollars.

It is essential that the any pump that is specified for a WUI apparatus should be some logical combination of the NFPA 1901 (250 gpm at 150 psi) and the National Wildland Coordinating Group’s Type-3 engine (150 gpm at 250 psi) standards. It should be noted that the NWCG standard assumes the need to pump a long hoselay uphill. While this is pretty common in a wildland scenario, it isn’t often done in the urban interface. It also should be noted that the NFPA specification delivers both the capacity and pressure that reasonably would be required and thus meets our interface needs.

Sufficient nozzles, fittings, wyes, reducers and thread adapters are critical. The nozzles need to be the dual-gallon, lightweight plastic, inexpensive type, and not the expensive structure type. During a fast-moving WUI fire, nozzles often get left behind, never to be recovered. Most federal wildland agencies have a normal unit stocking list that might be helpful. Among the items are sufficient hand tools — at least one of each type McCleod, combi tool, wildland shovel, and Pulaski — and a well-maintained chain saw, which is used mostly for clearing brush around structures, trimming tree branches, and clearing pathways for access and egress.

Aim High

The WUI engine also should have one all-purpose 10- to 12-foot ladder. I can’t tell you how many strange looks I’ve received after making this suggestion — a ladder on a wildland engine? However, a few of those strange looks changed when we needed to access the roof and the homeowner’s ladder was not available. The 10-foot folding attic ladder that my previous department carries has been used to apply structure wrap — a protective aluminum covering — to entire structures, to clean out gutters jammed with small twigs and leaf litter, and to access the roof to put out small ember-started fires. There are a multitude of other possible uses.

Often in WUI fires, the only water is a swimming pool, creek, pond or lake. So, the apparatus needs to have a draft hose of a size and length to meet the need. Recently we responded to a 7,000-acre fast-moving, wind-driven WUI fire that threatened 50 houses. They were nice homes, and many had swimming pools, but there wasn’t a fire hydrant anywhere to be found.

Fortunately, we had a tender available for this fire. But had we not had that capability, our choice would have involved drafting water from the swimming pools. Ideally, lightweight 2H-inch hose in 8- to 10-foot lengths would be used for this purpose. A foot valve also is essential because it makes it easier to draft.

A small float pump or lightweight pump is a bonus. The latter is preferred. Once, the main pump went out on a brush engine and the engine crew used a portable pump to draft from the booster tank — something that is not possible with a float pump.

There are a few more things to consider. Larger, puncture resistant tires are very important as is a spare and the right tools to change it. Although the need for all-wheel drive has been debated, it is my experience that it provides an extra measure of safety should I go where I shouldn’t have gone.

Regarding the chassis, basically there are two choices: a 19,500 GVWR that likely will be maxed out when outfitted with the above gear and the body; or a larger, more expensive—and possibly less maneuverable—chassis having substantially more GVWR, e.g., a short-wheel-base, extended-cab Ford F-650 or F-750 with all-wheel drive or an International 7400 extended cab.

What’s Your Type?

All of this will be a balancing act worthy of the Ringling Brothers and Barnum and Bailey Circus. Cost, size, GVWR, maneuverability and reliability all must be contemplated. It’s also important to consider the roads that a WUI apparatus will encounter: are the roads mostly paved; are they somewhat improved but sill mostly rocky; or are they rough, two-track paths through the woods?

One enormous consideration is whether this apparatus has to fulfill the routine everyday fire district engine function as well, i.e., does it require an ISO-rated pump and related structure gear? If it does, the smaller truck, which is better-suited to the interface, will not be an option. If the apparatus needs to have a higher-rated pump capacity, this also eliminates the smaller truck.

Finally, it is important for all of us to know and apply the national engine-typing criteria when designing and specifying our wildland engines, because WUI fires often are regional events that require resources from outside the area. When an incident commander orders a strike team of Type-3 engines, he needs to know that he’ll get them.

Larry Marcum is chief of the North Hays County (Texas) Fire and Rescue Department.

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