Beware of the Mansard Roof

(1) A mansard roof. [Photo courtesy of the Prospect Heights (IL) Fire Protection District.]

(2) The exposed wall and roof show the mansard roof framing, where vertical members intersect with the horizontal members, creating large, open voids that permit fire spread. (Photo by Tim Olk.)

Estimating Fire Spread

The role of construction cannot be underestimated. Simply knowing the type of construction such as wood frame, ordinary, or even fire resistive will not paint a complete picture. Formal preplanning and periodic structure familiarization at complexes are essential. When walking through complexes, have a guided discussion about how the building is built; what types of structural members are used; the fire resistance or combustibility of a structural member; and whether it’s wood, engineered lumber, or noncombustible components such as steel or concrete. The arrangement of these components will dictate the ability of ventilation to feed fires in concealed spaces. Traditional framing uses 2 × 4 or 2 × 6 studs spaced on 16- or 24-inch centers. The framing for a mansard roof or parapet/façade often combines many framing elements that create deep and wide spaces that allow large amounts of airflow. It is precisely this airflow that promotes and distributes fire spread. On a building familiarization activity, being able to see into the spaces and the framing arrangement will give a brilliant picture of the fire spread potential.

Wind goes hand in hand with construction. The “dynamic duo” for fire spread is plenty of space with plenty of air. When this space exists and wind forces in the air, the recipe for fire spread is almost ideal. A space doesn’t have to have a large independent fuel load. Between the structural members made of combustible materials and large volumes of combustible fire gases, wind will force air into the space, creating the ideal flammable range. Once ignition occurs, the wind will cause replacement air to enter the space at a faster pace, and fire conditions will grow exponentially over a matter of minutes. The only thing that will limit fire spread will then be the ability of the newly created fire gases to exhaust and leave the space so that a new, equal amount of “makeup” air enters the space expanding the combustion.

Wind needs only approach 10 miles per hour (mph) to become a real problem. With buildings more than two stories tall, it is not unusual to have greater wind speeds above grade level, which could be as much as 20 mph greater. Wind will greatly influence the fire behavior; do not underestimate it. Get in the habit of noticing the wind direction and speed. Everyone on the fireground should do this, not just the incident commander (IC). There are easy, practical rules of thumb to visually interpret wind speed such as flag behavior. 

Reacting

With our knowledge of the fire’s behavior and predicted future behavior, proper apparatus positioning is what allows us to rapidly deploy our hoselines to the seat of the fire as well as enables us to put ladders where they are needed. Apparatus positioning for engines and ladder companies cannot be an afterthought; it must be preplanned immediately on arrival. We may not get a chance to take the best position if we don’t take our best position on arrival. There are no time-outs or do-overs in firefighting.

Coupled with our efforts to position apparatus effectively comes our ability to simply access the complex or property in the first place. Our chosen travel routes allow us to see some, all, or none of any given structure. Travel routes that maximize our visual observations directly impact our ability to position the apparatus most effectively. Choose travel routes that do not delay your response but improve your visual observation. Be purposeful in your route selection.

Upgrading the Alarm

Once we’ve estimated the fire’s behavior for the immediate future, we have a good idea of what resources we will need. This is a point where wishful thinking does not help; you must be deliberate and purposeful in ordering extra alarms. Asking for individual resources one after the other is a futile effort. Extra alarms must be organized in a purposeful manner. A predetermined number of resources such as engine, ladder, and other companies that support the fireground must be preplanned and by the fire department and also include the communication center that must dispatch these resources. The dispatch center must be in on the preplanning effort if the fire department is to expect an efficient and swift dispatch of additional alarms.

The number of companies needed on a routine residential fire will be insufficient for these large complexes. You will likely be dealing with larger 2½-inch handlines, which will need more than one company per line to maneuver on the interior. You will likely need more than one company to open up any segment of the roof. Water supply may also be an issue, as hydrants outside the complex may need to be accessed by later-arriving companies. As you order additional alarms, your companies will travel from farther and farther away. Are you accounting for this travel time in your reflex time?

Checking for Extension

If interior companies can make a swift knockdown on the fire and quickly move in to check for extension, where should they check? Likely, they will open up walls and ceiling in the immediate vicinity of the fire, as they should. However, if they begin to find extension into the attic space, their movement should be to the far end of the building and then work their way back to the fire room.

Checking the fire room only to find fire, and then checking the adjacent room only to find fire, then checking the next adjacent room to find more fire means you’re behind the curve; the fire is ahead of you and your company. You need to get ahead of it, and the way to do this is to go to the far end of the building (within reason) and work your way back. If you get to that far end of the building as you find fire, you know you have a huge problem. If you get to the far end of the building and there is yet to be fire, you have a more advantageous position. 

Roof Ops

When the IC assigns companies to open the mansard roof, he needs to be clear about the objective. Saying “Open the roof” doesn’t communicate the strategy. Is the objective ventilation or separation? What is your goal? Ventilation isn’t achievable unless water application is winning. In defensive mode, consider separating the burning area from the area than can be saved. Separation is resource-intensive and time consuming. Planning and resourcing are critical to a successful undertaking; it’s not a one-company solution.

The roof crew should place inspection holes to gauge fire spread so they don’t cut themselves off from their means of egress or wind up making openings that will be pointless. Roof openings intended for separation need to be far enough away from the fire to not only be completed but serve their intended purpose. How effective will you be at opening up a mansard roof from a portable ladder? How long will you be able to safely hold a power saw, particularly if you need to hold it above your head (should you even be doing that in the first place)? Is it more efficient and safer to open the vertical surfaces of these roofs from an aerial platform or the balcony of a particular unit? Choose an operating position that will increase success and member safety.

(3) There is a large void space in the attic of this mansard roof. Severe charring from fire spread is noted. (Photo by Tim Olk.)

(4) Using a saw while at a steep angle on a ground ladder. Faster and safer access to the void space may be achieved from a balcony or aerial platform. (Photo by Steve Redick.)

Those fire companies closest to the fire must understand and assess where the fire has been, where it is, and where it might go. How do you do that? With a lack of fireground experience on these fires, generate “other” knowledge. Academic study of fire behavior and construction coupled with a review of video from other fires are a terrific aid. When viewing video, pay attention to the fire and smoke, what it does, and how long it takes to spread. Qualify your observation by using your academic knowledge to compare observations from other videos or actual fires and by keeping in mind any timeline interrupted by the starting and stopping of the video. For any given fire video, a compilation of segments results in unaccounted for periods of time. How long these interruptions last and what happens from one segment to the next are important conclusions and cannot be made without some degree of uncertainty. Last, evaluate the quality and expertise of anyone narrating the video. Why should you believe or not believe that person? It may be helpful to mute the video and pay attention only to the visual.

It is a long-established guideline that firefighters have two ways off every roof. What exactly does that mean? Placing aerials, apparatus, or ground ladders will be sufficient, but what is the placement? I prefer to ladder remote from the work area on the side that is likely to be exposed to fire last. This permits the entire company to not only get on the roof and move to the work area but, when conditions deteriorate rapidly, the entire company could make it to a safer area and then get on the ladder vs. accumulating near the ladder in a higher-risk area. If there is more than one company assigned to the roof, will one ladder—aerial or ground—be sufficient to get everyone off the roof in a timely manner? Consider one ladder per company for egress. Those ladders may be placed side-by-side or positioned on opposite sides of the building but not opposite sides of the fire. 

Choosing the roof as the work area is a combination of knowledge and experience plus the company officer’s estimate of what needs to be accomplished and how fast. Generally, if the goal is to create separation between the burning area and the unburned area, then the work area needs to be far enough away from the fire to allow the work to be accomplished. If company staffing results in two or three members going to the roof, how much work will they be able to accomplish and how fast? If your goal for separation is a hole four times the size of your regular residential roof hole, is one or two companies sufficient to get the work done quickly? How many saws will you use? Every company assigned to the roof should bring at least one saw along with a full complement of the appropriate hand tools. 

LCES and the Roof Safety Officer

To borrow from the wildland firefighting community, the roof sector/division/group officer has one main job: LCES—Lookout(s), Communication(s), Escape routes, and Safety zone(s). Plan the escape route and egress path to ensure adequate ladders have been placed and the companies have been alerted to their locations. Make sure that companies stay within the safe zone and do not place the fire or their work (the hole) between themselves and their egress; this position is best staffed by a chief officer. A company officer’s first duty is to his company members. A chief officer can look out for all the companies and not be needed to participate in the tasks at hand.

Beware of the mansard roof! Its construction, combined with even the slightest wind, will permit fire to spread rapidly. Knowing your buildings and their construction is necessary to estimate fire spread. Develop your estimating skills by learning from others, particularly through video.

With the knowledge of what you determine will happen, ensure you have enough resources to win. This means upgrading the alarm level quickly and in a predetermined and well-structured manner. A large number of companies will be necessary to swiftly check for extension or conduct roof operations that separate the fire from the unburned portions of the structure. If you need to do both (and that’s very likely), your resource pool will need to be even deeper. To win these battles, do not underestimate the fire problem, and present a firefighting force that is large enough and trained well enough to overwhelm the fire.

DREW SMITH, BS, EFO/CFO, LP, is a 40-plus-year fire service veteran and the chief of the Prospect Heights (IL) Fire Protection District. He has worked the past 31 years as a chief officer and has been a member of volunteer, combination, and career departments. Smith is an experienced training officer, regional academy director, regional TRT director, statewide TRT committee chair, and college faculty with multiple firefighting, special operations, officer, and instructor/training manager certifications. He has led the formation of a new fire department, implemented fire department-based paramedic ambulances, transitioned from volunteer to career staff, and implemented the first aerial apparatus into fire departments. Smith is a member of several state and national fire service organizations and has presented at FDIC International as well as state and regional conferences over the past 28 years.