Fire Studies: Lumberyard Fires: Part 2

Fire extension at a lumberyard can occur in a combination of ways. The large volume of radiated heat can ignite structures and piles of lumber a distance away. Convected hot gases can take fiery brands on upward currents of air away from the fire and, as the currents cool, allow the brands to settle on exposed structures or wildland areas, igniting independent fires remote from the original burning site.

Brand patrols must be organized with the responsibility of checking areas downwind for fire extension. Checking nearby roofs can consume a great deal of resources. Urban lumberyards can be surrounded by dwellings or commercial properties that restrict access and firefighting capabilities, setting the stage for a possible conflagration.

A fast-moving fire may require the relocation of apparatus. Shutting down pumpers for relocation purposes will require additional hoselines stretched to piece out the existing stretches or connecting the already stretched hoselines to available outlets on other apparatus or outlets on large-diameter hose.

 

Establishing a water supply

Large quantities of water will be required if the fire is past the incipient stage. Water will be needed to reduce radiant heat, knock down the spreading fire and reduce flying brands. Exposed buildings and piles of lumber must be wetted down. Knowledge of the water supply, including hydrant locations, water main sizes and drafting sites, will be needed.

Many fire departments do not let pumpers attach to hydrants directly in front of the fire building to prevent the possibility of what occurred to the apparatus in the opening scenario (see part one). The destruction of two fire department engines can have an immediate impact at the incident. The hoselines that were being supplied by those pumpers could no longer place water on the fire, allowing it to spread. The pumpers that were relocated now had to find hydrants that would be farther away than normal due to the extra-alarm companies taking the closer available hydrants.

Water runoff can be massive. Hoselines can be completely covered with runoff water, negating the ability of firefighters operating in heavy smoke and reduced visibility to retrace their steps by following the hoseline out of the area.

When the fire is under control, handheld hoselines can be employed for overhauling. This will be a time-consuming venture, but it can be facilitated by the use of forklifts. They can raise the lumber while firefighters drive water into and beneath the piles. Water should be used abundantly until no doubt is left that the fire is out. During overhaul, burned piles of lumber can become unstable; shifting piles must be monitored.

 

Fully enclosed lumberyards

There has been a change from traditional outside lumberyards to a one-stop shopping concept. Businesses such as Home Depot and Lowe’s are contained in large buildings with ceilings up to 60 feet high. The problems normally associated with exterior lumberyards spread over many acres are now contained within one building. This concept places many hazards under one roof, including pesticides, plastics and combustible liquids.

The ability of a fire department to fight a fire successfully in these structures depends on a properly installed and operating sprinkler system. This should include in-rack sprinklers. These large enclosed structures can be handled with the assistance of the sprinkler system. Should the sprinklers fail to operate properly, the potential for a disastrous fire exists.

These occupancies could require an upgraded response due to the large number of occupants during hours of operation. Firefighters should anticipate problems with ventilation and evacuation.

Summary

The fire incident described in part one of this column severely challenged the responding firefighters, destroyed a thriving business and devastated the surrounding neighborhood. It shows that a fast-moving fire must be anticipated and the criticality of apparatus placement. Fireground commanders must read the cues an incident presents and react accordingly.

Heavy smoke conditions with limited visibility at street level, as happened at this fire, indicated a fire starving for oxygen and conditions that were ripe for a fast-moving and dangerous fire. There must be recognition of the tremendous amount of combustible materials that are contained within a lumberyard and the fuel it will supply to a fire. The nearby exposures presented not only the ability for the fire to spread to these structures, but threatened the life safety of the occupants. n

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