Primary Causes of Office Fires
In any investigation of the causes of office fires, the “usual suspect” is the electrical system. In fact, various defects in electrical wiring or the improper and careless use of electrical equipment were the probable cause of 30 percent of the office fires that occurred from 1985 to 1989, according to a study by FME&R. Fire threatens whenever the protective insulation of wires or cables is damaged and where faulty installation or operating conditions result in loose connections and splices.
In addition, the growing use of electric coffee makers, hot plates, and portable electric heaters has greatly increased the risk of office fires.
Another prevalent, but certainly more difficult to detect cause of fire is incendiarism. Accounting for about 20 percent of office fires, incendiarism claimed about 40 percent of total losses—more than $24.2 million in losses from ’85 to ’89.
While much attention has been given to the health risks posed by smoking, its role as a major cause of fire has rarely made it into the headlines. The countless cigarettes and matches used by smokers pose a substantial threat that can be easily minimized through education and simple office procedures.
Still another cause of fires contributing to significant property loss comes under the heading, “exposure.” Office fires can start because of heat radiated from a fire in a nearby structure, in yard storage, or in adjacent vegetation.
Fuel To The Fire
In today’s office, a significant amount of combustible materials is more likely to be the rule than the exception. Office furnishings, such as wooden desks, chairs and bookcases, upholstered furniture, plastic cushions and office machinery, all provide fuel for fires.
Interior finish and construction also can contribute to the combustible loading. Some areas might have plywood, hardboard or solid lumber wall paneling, vinyl wall covering, wooden doors, carpeting on floors and walls, built-in wooden cabinets, wooden area dividers or movable partitions between work areas.
Reduce Number of Combustibles
A key way to safeguard against office fires is to reduce the number of combustible materials. Consider using metal office furniture (particularly wastebaskets) and limiting the availability of upholstered furniture. Instruct employees to keep as many combustibles inside desks and cabinets as possible. And be sure that the wall furnishings, drapes, ceilings and carpeting purchased by your company are low in combustibility.
In addition, you should be sure that fire protection systems are in operating condition by scheduling frequent inspections and testing. Check activating devices, such as fusible elements on sprinklers and smoke detectors, to ensure that they are not loaded with residue or otherwise impaired.
Also, strategically locate portable fire extinguishers and select the proper extinguisher to protect a particular situation or fire hazard. Make sure to train key employees on proper operation of these devices, and have hydrostatic testing done at periodic intervals to assure that they are in proper working condition, in accordance with standards set by Factory Mutual Research Corporation, the non-profit research arm of FME&R.
Office Occupancy Renovation
Additional fire hazards are introduced into office environments during office occupancy renovation. Often, the renovation brings about the shut-off of fire protection systems or water-control valves. Paints, cleaning solvents and other highly combustible materials often are present during renovations without adequate storage or ventilation. In addition, dangerous, portable open-flame equipment, such as torches, salamanders and space heaters, are often used.
During office renovations, automatic sprinklers should be installed if not already present. Managers also must take steps to assure that the environment will be at least equally safe after the renovation. For instance, when having suspended ceilings installed, be sure to provide sprinkler protection above as well as below the ceiling when the roof or floor deck above is combustible (as is sometimes the case in low-rise office buildings) or the space contains combustibles capable of sustaining a spreading fire.
Insurance alone will not protect assets. Companies must adopt aggressive risk-identification and loss prevention programs in order to avoid the losses and tragedies that can result from office fires.
The High Risk Of HighRises
While the potential for property loss exists in any office environment, it is made greater in a high-rise office building. The most obvious reason is that the combustible loading found in any normal office environment is multiplied by 10 or 50 or 100 floors. And, since upper floors are beyond the reach of available fire department aerial equipment, fire-fighting efforts and evacuation are generally handled from inside the building, greatly increasing risk.
Consider, too, that modern high rises often house more than offices. Many are mixed-use facilities with offices, retail stores, restaurants and even small manufacturing and commercial operations. Such establishments contribute such things as merchandise, decor, furnishings, gas- and electric-fired cooking appliances, and packaging materials to the combustible content of the building’s offices. Residential occupancies such as apartments, hotels, and dormitories also have combustible furnishings and kitchens with cooking appliances.
What’s more, the construction characteristics of modern high-rise office buildings create their own unique fire hazards. Extensive use of glass in building walls permits fire to pass vertically from floor to floor. For instance, when windows are large and close together vertically, fire engulfing a large area of one floor will fan upward toward the windows or will radiate through intact windows and set combustibles on fire inside.
Another major pathway for exterior fire spread is the curtain wall. Open space might exist between each floor slab and the interior face of the curtain wall. Added space might be within a cavity wall or sandwich-panel double-panel wall. Flames from the interior can spread via foamed plastic insulation within such spaces.
Internal fire spread can occur through open stairwells or elevator shafts and in ductwork or “poke-throughs” (utility openings in floor slabs). Poke-throughs are always found in high-rise buildings, particularly in older buildings that have undergone several tenant alterations.
Other avenues of internal fire spread are long narrow chases, chutes, raceways and dumbwaiters for piping, conduit, grouped wiring, trash removal and laundry transfer.
Atria provide a massive chimney effect, and heating, ventilation and air-conditioning (HVAC) ducts can circulate smoke, heat and toxic gases to large areas remote from the fire.
As if that’s not enough cause for concern, consider that even the most basic construction elements of a high-rise can contribute to overall fire damage. Structural steel rapidly loses strength as its temperature exceeds 1,000 F and localized collapse is likely, making adequate fire protection of such structural elements essential.
Insurance alone will not protect assets. Companies must adopt aggressive risk-identification and loss prevention programs in order to avoid the losses and tragedies that can result from office fires. Certainly such a program need not be expensive. For instance, FME&R has found that the cost of installing sprinklers in a new building is comparable to the cost of wall-to-wall carpeting. And many loss prevention programs can be implemented for minimal cost. The catastrophic fires that have occurred in recent memory make a compelling argument for introducing such programs at your company.
This article was submitted by Factory Mutual Engineering & Research.
This article adapted from Vol. 5 #2.