March-April 2008

The Finer Points of Exposure Protection

By Michael West

Many classes on strategy and tactics use the acronym RECEO to describe the order of importance of tactical factors.  According to RECEO, after we have handled the rescue efforts then we move on to exposure control.  While the concept is straight forward and common sense, sometimes incident commanders may miss the finer points of exposure protection. Here are a few points that should be considered when faced with a rapidly expanding incident that threatens to burn down more than one building.

1. Recognize the impact of building construction and design in the spread of fire.  Space plays an important role in exposure issues but so too does the construction of the building. Note the locations and numbers of openings such as windows. The more openings, the easier it is for fire to spread from one structure to the next.  The material a building is made of can also play an important role. Buildings of masonry construction along side of one another can allow fire to spread, but not nearly as rapidly as wood framed buildings or worse yet, buildings with asphalt siding (Photo 1).

   Photo 1 – The asphalt siding, narrow space, and multiple windows of the fire building and exposure make this a difficult situation.  Add the fact that the fire building appears to be vacant and the chance of rapid fire spread to the exposure is compounded.  Photo courtesy of Damian Emerick, NFD

2. Examine the potential for the fire building to collapse into the exposure and plan accordingly. If you are operating in the defensive mode in the fire building it is important to take a careful look at the possibility of collapse.  If it does collapse toward the exposure, is there a chance of collapsing the exposure or trapping members working in the exposure (Photo 2)?

   Photo 2 – The four-story tenement has been written off. With its distance and construction type, collapse is a possibility and a careful risk/benefit analysis should take place regarding operations in the “D” exposure. Photo courtesy of Chief Kevin Keddy, APFD

3. What hidden hazards may be present in the building that can cause a violent change in the fire condition or cause an explosion or catastrophic collapse? In older jurisdictions, multiple layers and levels of ceilings can cause large voids for fire to build up in. The possibility of a backdraft, once the ceiling layers collapse can cause a collapse of the fire building that may lead to extension or endanger firefighters working in or on the exposure.  Consider the presence of HAZMAT, flammable gasses, or pressurized vessels that may also let go violently and cause a similar issue.  Call for the local gas company to send a representative to assure that the natural gas lines into the buildings has been secured  (Photo 3).

4. After considering #2 and #3, place lines inside the exposure(s) as needed. Because you are defensive on the fire building does not always dictate being defensive on the exposure.  It’s important to look at each building on the fireground both as a set and as individual structures.  Whenever possible, exposure protection should include lines and personnel on the inside of the exposure, checking for extension and taking steps to limit the chance of extension before it happens. When working in the exposure, take down combustible coverings at the windows and attempt to leave windows intact to reduce fire spread. Close them if they happen to be open.  Place lines that have enough length to cover all of the exposed floors and if that’s not possible, place multiple lines as needed (Photo 4).

5. Back on the outside, place large lines on the exposed exterior surfaces and take care to keep exposure windows intact. Recognize the limitations of ground based lines and master streams. Beyond the 3rd floor or so, their ability to penetrate into the fire building is greatly reduced. The use of tower ladders is very effective on covering exposures and units with two master streams can simultaneously cover the fire building and exposure. Be thoroughly familiar with your apparatus and their capabilities.  Remember to save a spot for second or third arriving apparatus (Photo 5).

6. Use a thermal imager to help direct streams through the smoke to the most needed areas and also to determine where exposures are most threatened. By placing the camera in a tower ladder on a high vantage point like a roof, the trained camera operator can help assure the streams are hitting their intended target (Photo 6).

7. Assign a water supply officer or planning chief to look at where and what lines are in service and determine how to maximize your potential flow as needed.  At large scale operations, the IC may not be able to see which streams are having the desired effects and which streams should be shut down to free up water elsewhere. Assign a competent command officer to take a walk about and see what is working and what is not. Remember that the scene is dynamic and just because the current arrangement of resources is working now, it is worth reevaluating after a period of time to see what has changed.

8. Last but not least is the important concept of having a realistic approach to the incident. While we are all optimistic that we can handle the fire in front of us without burning down the block, it is important for the IC and Division supervisors to plan for the worst and work on contingency plans should the fire extend to multiple exposures. Pessimistic apparatus placement (placing with collapse and defensive operations in mind) should be considered at any incident where large volumes of fire are noted on arrival and the incident commander is starting from a defensive posture. Consider the possibility of total involvement and plan accordingly (Photo 7).

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