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
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
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
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,
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
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
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 firstname.lastname@example.org
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
Used by permission.