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NFPA 921 Section 10-1 through 10-2.7

[interFIRE VR Note: Tables and Figures have not been reproduced.]

10-1* General. Fire scenes by their nature are dangerous places. Fire investigators have a duty to themselves and to others who may be endangered at fire scenes to exercise due caution during their investigations.

10-1.1 Investigating the Scene Alone. Fire scene examinations should not be undertaken alone. A minimum of two individuals should be present to ensure that assistance is at hand if an investigator should become trapped or injured.

If it is impossible for the investigator to be accompanied, he or she should, at the least, notify a responsible person of where the investigator will be and of when he or she can reasonably be expected to return.

10-1.2 Safety Clothing and Equipment. Proper safety equipment - including safety shoes or boots, gloves, safety helmet, and protective clothing, such as coveralls or turnout gear - should be worn at all times while investigating the scene.

Certain other equipment might also be necessary to maintain safety. This equipment includes flashlights or portable lighting, safety glasses or goggles, appropriate filter masks or self-contained breathing apparatus (SCBA), lifelines or nets, ladders, and hazardous environment suits. Some of this equipment requires special training in its use. The investigator should not attempt to use personal protective equipment or other safety equipment without the appropriate training.

10-1.3 Fire Scene Hazards. The investigator should remain aware of the general and particular dangers of the scene under investigation. The investigator should keep in mind the potential for serious injury at any time and not become complacent or take unnecessary risks. The need for this awareness is especially important when the structural stability of the scene is unknown or when the investigation requires that the investigator be working above or below ground level.

10-1.4 Personal Health and Safety. The investigator should be cognizant of factors associated with chemical, biological, radiological, or other potential hazards that may threaten personal health and safety while conducting fire scene examinations. Where these conditions exist, special precautions should be taken as necessary. Special equipment such as rubber gloves, specialized filter masks or self-contained breathing apparatus (SCBA), or hazardous material suits may be required.

10-1.5 Investigator Fatigue. It is common for investigators to put in long periods of strenuous personal labor during an incident scene investigation. This may result in fatigue, which can adversely influence an investigator's physical coordination, strength, or judgment to recognize or respond to hazardous conditions or situations.

Periodic rest, fluid replacement, and nourishment should be provided. This is particularly necessary on large or major incident scenes.

10-2. Factors Influencing Scene Safety. Many varying factors can influence the danger potential of a fire or explosion scene. The investigator should be constantly on the alert for these conditions and should ensure that appropriate safety precautions are taken by all persons working at the scene.

10-2.1. Status of Suppression. If the investigator is going to enter parts of the structure before the fire is completely extinguished, he or she should receive permission from the fire ground commander. The investigator should coordinate his or her activities with the fire suppression personnel and keep the fire ground commander advised of the areas into which he or she will be entering and working. The investigator should not move into other areas of the structure without informing the fire ground commander. The investigator should never enter a burning structure unless accompanied by fire suppression personnel.

When conducting an investigation in a structure soon after the fire is believed to be extinguished, the investigator should be mindful of the possibility of a rekindle. The investigator should be alert for continued burning or a rekindle and should remain aware at all times of the fastest or safest means of egress.

10-2.2. Structural Stability. By their nature, most structures that have been involved in fires or explosions are structurally weakened. Roofs, ceilings, partitions, load-bearing walls, and floors may have been compromised by the fire or explosion.

The investigator's task requires that he or she enter these structures and often requires that he or she perform tasks of debris removal that may dislodge or further weaken these already unsound structures. Before entering such structures or beginning debris removal, the investigator should make a careful assessment of the stability and safety of the structure. If necessary, the investigator should seek the help of qualified structural experts to assess the need for the removal of dangerously weakened construction or should make provisions for shoring up load-bearing walls, floors, ceilings, or roofs.

The investigator should also be especially mindful of hidden holes in floors or of other dangers that may be hidden by standing water or loosely stacked debris. The investigator should also keep in mind that the presence of pooled extinguishment water or of weather-related factors such as the weight of rain water, high winds, snow, and ice can affect the ability of structures to remain sound. For example, a badly damaged structure may only continue to stand until the ice melts.

10-2.3. Utilities. The investigator should learn the status of all utilities (i.e., electric, gas, and water) within the structure under investigation. He or she should know before entering if electric lines are energized, if fuel gas lines are charged, or if water mains and lines are operative. This knowledge is necessary to prevent the possibility of electrical shock or inadvertent release of fuel gases or water during the course of the investigation.

10-2.4. Electrical Hazards. Although the fire investigators may arrive on the scene hours or even days later, they should recognize potential hazards in order to avoid injury or even death. Serious injury or death can result from electric shocks or burns. Investigators as well as fire officers should learn to protect themselves from the dangers of electricity while conducting fire scene examinations. The risk is particularly high during an examination of the scene immediately following the fire. When conditions warrant, the investigator should ensure that the power to the building or to the area affected has been disconnected. The fire investigator should not disconnect the building's electric power but should ensure that the authorized utility does so.

When electrical service has been interrupted and the power supply has been disconnected, a tag or lock should be attached to the meter indicating that power has been shut off. In considering potential electrical hazards, always assume that danger is present. The investigator should personally verify that the power has been disconnected. If any doubt exists as to whether the equipment is energized, call the local electric utility for verification.

The investigator may be working at fire scenes that have been equipped with temporary wiring. The investigator should be aware that temporary wiring for lighting or power arrangements is often not properly installed, grounded, or insulated and, therefore, may be unsafe.

The investigator should consider the following electrical hazards when examining the fire scene:

(a) Consider all wires energized or hot, even when the meter has been removed or disconnected.

(b) When approaching a fire scene, be alert to fallen electrical wires on the street; on the ground; or in contact with a metal fence, guard rail, or other conductive material, including water.

(c) Look out for antennas that have fallen on existing power lines, for metal siding that has become energized, and for underground wiring.

(d) Use caution when using or operating ladders or when elevating equipment in the vicinity of overhead electric lines.

(e) Note that building services are capable of delivering high amperage and that short circuiting can result in an intense electrical flash with the possibility of serious physical injury and burns.

(f) Rubber footwear should not be depended on as an insulator.

(g) A flooded basement should not be entered if the electrical system is energized. Energized electrical equipment should not be turned off manually while standing in water.

(h) Avoid operating any electrical switch or non-explosionproof equipment in the area that might cause an explosion if flammable gas or vapors are suspected of being present. (See 10-2.7.) When electric power must be shut off, it should be done at a point remote from the explosive atmosphere.

(i) Establish lines of communication and close cooperation with the utility company. Power company personnel possess the expertise and equipment necessary to deal with electrical emergencies.

(j) Locate and avoid underground electric supply cables before digging or excavating on the fire scene.

(k) Be aware of multiple electrical services that may not be disconnected, extension cords from neighboring buildings, and similar installations.

(l) Always use a meter to determine whether the electricity is off.

10-2.5. Standing Water. Standing water can pose a variety of dangers to the investigator. Puddles of water in the presence of energized electrical systems can be lethal if the investigator should touch an energized wire while standing in a puddle.

Pools of water that may appear to be only inches deep may in fact be well over the investigator's head. Pools of water may also conceal hidden danger such as holes or dangerous objects that may trip or otherwise injure the investigator.

Investigators should be cognizant of these hidden dangers and take proper precautions to avoid injury.

10-2.6. Safety of Bystanders. Fire and explosion scenes always generate the interest of bystanders. Their safety, as well as the security of the scene and its evidence, should be addressed by the investigator.

The investigation scene should be secured from entry by curious bystanders. This may be accomplished by merely roping off the area and posting Keep Out signs, or it may require the assistance of police officers, fire service personnel, or other persons serving as guards. Any unauthorized individuals found within the fire investigation scene area should be identified, their identity noted, and then they should be required to leave.

10-2.7. Safety of the Fire Scene Atmosphere. Fires and explosions often generate toxic or noxious gases. The presence of hazardous materials in the structure is certain. Homes contain chemicals in the kitchen, bath, and garage that can create great risk to the investigator if he or she is exposed to them. Commercial and business structures are generally more organized in the storage of hazardous materials, but the investigator cannot assume that the risk is less in such structures. Many buildings older than 20 years will contain asbestos. The investigator should be aware of the possibility that he or she could become exposed to dangerous atmospheres during the course of an investigation.

In addition, it is not uncommon for atmospheres with insufficient oxygen to be present within a structure that has been exposed to fire or explosion. Fire scene atmospheres may contain ignitible gas, vapors, and liquids. The atmosphere should be tested using appropriate equipment to determine whether such hazards or conditions exist before working in or introducing ignition sources into the area. Such ignition sources may include electrical arcs from flashlights, radios, cameras and their flashes, and smoking materials.

* A-10-1 For additional information concerning safety requirements or training, see appropriate local, state, or federal occupational safety and health regulations.

For more information, contact:
The NFPA Library at (617) 984-7445 or e-mail

Taken from NFPA 921Guide for Fire and Explosion Investigations 1998 Edition, copyright © National Fire Protection Association, 1998. This material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.

Used by permission.

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