Firefighter Risk in Nonresidential Occupancies
DEPARTMENTS
Robert Obermayer’s Training Notebook
Seventy-three percent of all structure fires in 1986 occurred in residential occupancies, the National Fire Protection Association reports. Given those statistics, fire service leaders, much to the detriment of the firefighters in their charge, may overlook the hazards that operations in nonresidential occupancies pose to firefighters. But NFPA statistics indicate the danger there is way out of proportion to the number of incidents: In 1985, the firefighter death rate in residential fires was 3.4 deaths per 100,000 fires; in nonresidential fires, it was 10.5.
Let’s examine the construction and content characteristics of nonresidential occupancies that create such high levels of risk.
To begin, we’ll define risk as the chance of injury or loss, and for our purposes, risk may be thought of as the probability of firefighters sustaining injuries during suppression operations. Further, we may define nonresidential occupancies as those whose primary purpose is to provide space for commercial, mercantile, or industrial operations rather than for human habitation.
The size-up factors in nonresidential occupancies may be viewed as risk enhancers, those factors that accentuate the level of risk; and risk mitigators, factors that modify or reduce risk levels. Risk enhancers include the specific characteristics of the occupancy’s contents and construction, and, perhaps, even the standard operating procedures of the responding fire department. Risk mitigators comprise the various features, such as automatic suppression systems, detection systems, and standpipe systems, that seek to prevent fire ignition, retard fire growth, and limit the fire’s impact on the occupancy’s structural integrity and habitability. Additional risk mitigators may be the quality of the local officership, incident command, SOPs, and firefighter training.
The first risk enhancer we’ll discuss is the contents, which aren’t regulated by most fire prevention codes. The quantity of the contents, their fire-related properties, and their configuration can all add to risk. Stores, warehouses, and manufacturing establishments generally have more flammable contents than residential occupancies, and the enlarged fire load will support a hotter, more extensive fire of longer duration. The fire-related properties of the contents— such as the quantity of heat released, the rate at which it’s released, and the amount of smoke and fire gases produced during combustion—will combine to bring on flashover conditions more quickly, increase the impact of a contents fire on the building’s structural integrity, and make conditions inside more brutal for firefighters. Even the configuration of the contents—for example, whether they’re stored in piles or on racks—will affect fire growth and destruction, while possibly posing the additional hazard of falling contents.
The nonresidential structure itself may be a risk enhancer. A building of that type is likely to be much larger than a residential occupancy, making firefighter navigation, supervision, and communications more difficult. The larger area will increase the risk of interior attack teams becoming disoriented and lost, while at the same time making escape more difficult. Because they’re designed to accommodate commercial processes, nonresidential occupancies may offer limited means of egress which may be locked or barred. In addition to making entry and egress more difficult and time-consuming, this will reduce ventilation opportunities, thereby increasing the operating forces’ exposure to the risk of backdraft or smoke explosion.
The construction factor
The type of construction may constitute the largest single risk enhancer. Typically, cost is the paramount consideration, while aesthetics is less important than in residences. Whether the nonresidential building is of noncombustible, brick and wood joist, or wood frame construction, the major load-bearing elements are likely to be more exposed to the fire. This is particularly evident with the steel or wood roof trusses necessary to achieve the wide floor areas that nonresidential structures require. The implication is clear: an increased potential for structural collapse.
There are other factors that tend to make firefighter operations in nonresidential structures more hazardous. Most such buildings are occupied only during normal business hours, delaying discovery so that fire conditions are more advanced upon fire department arrival.
There’s always the possibility that the fire is the result of arson; if it is, the accelerants used will result in rapid fire development and earlier flashover. The structure may have been designed to accommodate a less hazardous (from a fire protection point of view) occupancy then it now houses, so that its fire-resistive qualities aren’t up to the demands a fire will make. Finally, the responding fire department’s officers or SOPs increase the risk if they don’t factor these hazards into the decision to commit forces to interior operations.
Reducing the risk
Turning to the risk mitigators, we find such features as automatic suppression systems, standpipe systems, and fire detection and alarm systems, which detect the fire, alert the fire department, retard fire growth, or minimize the time required to apply an extinguishing agent. The fire department will find a smaller fire of manageable proportions which doesn’t require dangerous and arduous interior operations, and which is less likely to threaten the stability of the structure.
Fire prevention and building codes, to the extent they’re enforced, cut down firefighter risk by reducing fire incidence and severity. Preincident planning and appropriate SOPs are also risk mitigators.
Last, high-quality fireground leadership and incident command, firefighter training, and protective equipment prepare the department and the individual firefighter for the dangers of nonresidential occupancies.
At residential fires, most SOPs call for an intelligent, immediate, and aggressive commitment of interior teams to support and perform the primary search. However, as we’ve seen, a fire in a nonresidential building is different and requires a different fire attack philosophy. SOPs should deemphasize the quick, sometimes unthinking initial attack and emphasize deliberate consideration of the risks involved in the commitment of interior forces.
If aggressiveness can be the theme in residential fire attack, then caution must be the theme of fire attack in nonresidential occupancies.
