EXPOSURE PROTECTION FOR WELL-INVOLVED STRUCTURES

BY JOHN “SKIP” COLEMAN

On September 6, 2005, Toledo (OH) Department of Fire and Rescue crews responded to a fire on Broadway Street in South Toledo. High winds from the Maumee River, directly behind these residential properties, fanned the fire. After more than 45 minutes, the fire was controlled. Still, one four-family apartment building and five residences (single-family and two-family structures) were destroyed.


1. Photos by author.

When the first crews arrived, two buildings (the apartment of origin and exposure B) were fully involved (photo 1). Soon after, a third house (exposure B1) was going as well (photo 2). Command requested a second alarm and special-called additional equipment. Eventually, close to the equivalent of a third-alarm response was requested.

Command assigned me side B on arrival. I assigned crews to pull lines between exposures B1 and B2 and to set up an aerial stream to cover the rooflines. As soon as more crews were on the scene, my next move was to get handlines inside exposure B2.


2

Unfortunately, low water pressure prevented me from completing the two handline assignments above. I had only enough water (probably around 200 gpm) to feed either the aerial or the handlines, not both. This incident occurred in an older part of town with six-inch or smaller mains. Access to mains on the other side of the street from the river was hampered by railroad tracks and several hundred feet of undeveloped brush-laden land.

Because of the excessive radiant heat, I opted to pull the handlines back and to operate the aerial stream to cover the roof until I could find more water. By the time more water was available, I had lost exposure B2 and was beginning to lose B3. There was a vacant lot next to exposure B3, where we set up and eventually stopped the fire.

The problem at this incident was a rapidly moving fire fanned by winds and a lack of water. I have asked myself dozens of times, Did I make the right decision in pulling out the handlines and trying to do the best I could with an elevated stream?

My rationale was that the firefighters on the line were in jeopardy because of the excessive radiant heat. Lights on apparatus parked six to eight feet away from the curb in the street were melting! Because of this intense heat, we needed straight streams for reach. Straight streams provide the least protection to firefighters on a handline from radiant heat.

Water curtains probably would provide the most protection, but I haven’t seen a water curtain on a rig for probably 15 years, and water curtains stop only approximately 15 percent of radiant heat; 85 percent would still be hitting the personnel on the line. By removing the handlines, I was protecting my firefighters. Had I removed the elevated stream, I would have provided more distance to the handlines and hence a safer attack, but that would have left the roof vulnerable to fire spread. Either way, I was going to lose the exposure, but removing the handlines was the safer option.

During fires where exposure protection is needed, many officers and incident commanders cover only part of the exposure problem. Exposure protection is an art, similar to conducting effective searches and fire attacks. Successful exposure protection includes three evolutions that all must be completed to save the exposed building.

#1: COVERING THE EXPOSED WALL SURFACE

The first priority is to cover the exposed wall assembly on the exposed building. The first consideration is the size of line to pull to cover the exposure. You should almost always deploy a 212-inch line for an exterior exposure line; it most surely will provide the water needed to cool the exposed surface. This line isn’t intended to move much. Once in place, it normally remains in place, and one firefighter can usually handle it.

The purpose of this line is to throw water on the exposed face of the exposure, letting the water wash down over the surface of the exposed wall to keep it below its ignition temperature. Direct the stream as high up on the exposed wall surface as possible, covering the wall, the eaves or soffits, and as much of the roof area as possible. Move it back and forth continuously until the threat of ignition is gone and the incident commander says it’s OK to shut down. Leave the line there in case it is needed later.

The next step in wall assembly protection is where to position the line. This is geometry! Find an angle that will allow the best and widest coverage of the exposed wall surface. If the exposure and the source building are relatively close (five feet or less apart, as in older neighborhoods), generally that position will be more in front of the source building. If you position in front of the exposure, you can surely hit the source fire (which is not the intent of an exposure line), but it’s awfully hard to curve water around a building. Hence, the line generally is placed more in front of the source building and on the side of-not in front of-the exposure. Once this line is in place, it should stay put.

A question often asked is, “Can I hit the source fire as well as the exposed side of the exposure?” Yes, you can periodically and sporadically throw water at the source fire, but your main task and objective is to throw water on the face of the exposed surface and keep it cool.

#2: COVERING THE ROOFING MATERIAL

The next exposure protection consideration is to cover the roof assembly if needed. Some exposure fires spread fire low on the exposure because of fire venting from windows and side doors or other openings (either man- or fire-made).

Often, depending on the location of the fire in the source building, the fire is also spreading from fire’s venting from roof openings (again, man- or fire-made-e.g., dormer windows in the attic or fire venting from the eaves, soffits, or vent holes). In this case, elevated streams, if available, work well to protect the roofing material on the exposure.

Again, the principle is the same: Direct the stream high on the roof assembly, and let the water wash down over the exposed roofing material to keep it below its ignition temperature. If elevated streams are not available, an exterior handline from the ground, positioned in close proximity to the exterior wall surface, will normally suffice. Again, this should be a 212-inch handline and should not be shut down until the incident commander orders it. One firefighter should be able to manipulate this line.

#3: COVERING THE INTERIOR

The last evolution of exposure protection is to get an interior line inside the house to check vulnerable areas of interior fire spread. Generally, this will be exposed window or other man-made openings and the attic eaves area. Lines used for interior exposure protection should be at least 134 inches. Larger houses or commercial exposures may dictate the use of larger lines.

Once inside, the interior exposure crew should first check the areas in most jeopardy. If the source fire is high (say, venting out of the second-floor windows and roof assembly), then the interior exposure crew should go to the second floor of the exposure (or the attic if the exposure is only one story) and check and protect the window openings. Remove all combustibles in front of the window, including curtains, bedding, dressers, and lamps. Monitor interior wall surfaces and interior window framing for heat.

If it is believed that fire has entered the wall assembly, then open and check the interior wall. If the source fire is extensive, use more than one crew to protect different openings (windows in different rooms) on the same level or floor, and perhaps use another crew for the attic area. If the source fire is small or the distance between the buildings is significant, then one crew can move back and forth throughout the different levels of the exposure, still removing combustibles from exposed openings.

One last word on interior exposure protection. Don’t just walk inside an exposed building, look around, determine there is no fire threat inside, and then leave the building without informing Command. If it’s my fire and I assign your crew to an exposure, in my mind, you are inside and staying inside until I tell you to come out or (if you are on air) your low-air alarms are about to sound. In that case, inform Command, and he will decide if he wants to replace you, let you change bottles and go back in, or suspend the operation.

Generally, one four-person crew can protect an exposure with one exterior handline and two or three firefighters can check the interior if it is unknown whether fire has moved inside the exposure. If Command knows or believes that fire has extended inside, then more than one crew will be necessary. On a close, well-involved fire, it would not be unusual to need three or four crews for interior handlines (one or two per floor and attic) plus a crew for search, ventilation, and salvage operations. I have been to many fires where a single-alarm assignment was used on each exposure and the source building.

JOHN “SKIP” COLEMAN, deputy chief of fire prevention, Toledo (OH) Department of Fire and Rescue, is author of Incident Management for the Street-Smart Fire Officer (Fire Engineering, 1997) and Managing Major Fires (Fire Engineering, 2000), a technical editor of Fire Engineering, and a member of the FDIC Educational Advisory Board.

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