Reflections on the Cause and Origin
Dr. Bernard Béland
Beland, Bernard. Reflections on the Cause
Fire and Arson Investigator. Vol 48, No. 1 (September 1997). p 8-9.
In the fire investigation process, it is generally agreed that one first
determines the point of origin and then, the cause. While the rule generally
applies, it suffers numerous exceptions as will be seen by examples to be
discussed. The most important result is that of finding the cause. Finding
the area of origin is just one of the steps that helps establishing the
cause. Sometimes, the point of origin could be found with some accuracy
but still the cause is unknown because there are too many possibilities
to consider with no means to eliminate all of them but one. In other instances,
the cause of a fire could be known with a high degree of certainty, even
though the point of origin is not known. Examples will be given of such
The semantic problem of using "cause and origin" or "origin
and cause" should not bother us in this article. The point of originor
at least the area of originis often found with a reasonable degree
of accuracy, assuming the damages are not too extensive. Alternatively,
there are numerous instances for which the point of origin is not clear,
even in the case of a limited fire that extends only to one room.
If one can determine both the point of origin and the cause from independent
facts and reasoning, then one has a very high probability of being right.
For example, if the probability of being right is 90 percent in each determination,
then the cause is known with a 99 percent certainty. However, this is very
seldom the case, since the two processes are often interrelated. In fact,
in numerous cases, one finds the area of origin. In that area, a beaded
wire is found. Then an electrical arc is pointed as the cause of the fire.
This process is wrong since an arc is a normal consequence of almost all
fires. The two events are dependent. For example, a fire could be set with
a match and paper in the vicinity of an electrical cord and a bead is most
likely to be produced. In such a case, the evidence of the arc is almost
useless by itself. It is just like the presence of charred wood. It is evidence
of the fire and not of the cause. However, if through an independent process,
it could be shown that the cord was severely overloaded to the point of
constituting a danger of fire in the presence of proper combustibles, then
the possibility of an electrical fire becomes acceptable. An overload just
above the ampacity of the National Electrical Code (NEC®)would not be
sufficient evidence. For example, 20A in a No. 14 AWG copper cable would
not be sufficient evidence. The load would have to be of the order of 50A
and sustained over a long time. The exact conditions would have to be evaluated
for each circumstance such as ambient temperature, thermal insulation and
All too often, the fire investigator determines the general area of origin,
then finds evidence of beading and concludes as to the cause. The report
then mentions that the exact point of origin was determined and, at that
point, only electricity could have caused the fire. Often the point of origin
was not clear by determined, and the report is silent on the exact nature
of the electrical fault and on the reason for the fault to have happened
so as to cause the fire. The electrical cause was used as an example, but
other causes could have been used to illustrate the point.
A few field cases will now be discussed briefly to illustrate the introductory
remarks. They correspond to actual cases that have been investigated, although
there could be some modifications to better illustrate the discussion. Most
of them would have been encountered by fire investigators, although the
details could vary.
CASE I (FLOATING NEUTRAL)
A truck ran into a triplex cable that fed a summer house and severed
the neutral. The house had no public water system and, therefore, the ground
was provided only by electrode rods driven into the soil. Severing the neutral
removes the house from the power company ground. The open neutral constitutes
a serious danger of fire, that is enhanced by the poor ground. A fire ensued
about half an hour later and completely destroyed the house. Under that
open neutral condition, some of the loads in the house are fed by a higher
than normal voltage while others are underfed. The actual values depends
on many circumstances; typical values could be 150 and 90V or some other
combination which sum equals 240V.
In such a case, the cause of the fire is known with a reasonable degree
of certainty. It is the floating neutral. This is the most probable cause
by a large margin. Other causes could be considered as a remote possibility,
but should be rejected unless other strong evidences are found. This is
a good example of a fire in which the point of origin is unknown but the
likely cause is very clear.
Other engineers working for the truck insurance company dug the debris,
found evidence of beaded wires and claimed that the fire was caused by electrical
malfunction that had nothing to do with the severance of the neutral. This
is not exceptional and is often encountered in practice. There is a tendency
to write a report that pleases the organization that retained the service.
A fire is a very uncommon phenomenon. In a given house, it does not happen
for years. If a fire happens almost simultaneously with the creation of
a dangerous situation, then, there is probably a relationship between the
process and the fire. That relationship can sometimes be removed but very
strong evidences must be presented to remove it.
CASE 2 (THAWING OF WATER PIPES)
On a very cold afternoon (-35°F), an oil-fired furnace broke down.
An electrician was called to install temporary electrical heating to prevent
the water from freezing and protect the facility. The installation was completed
around 10 p.m. and a fire was discovered some three hours later. The fire
completely destroyed the building. This author was called to investigate
the fire and, if possible, find evidence to recover the losses from the
The investigation revealed that the electrical work was well done. He
had used the proper size of conductors and the work was professional, at
least for a temporary work that was to be removed the next day after a new
furnace installation. The code was not adhered to in all details. For example,
cables to the heaters were run on the concrete floor without mechanical
protection. Although the code was not adhered too, that specific violation
constitutes no danger of fire and, it will be hard to blame the electrician.
An investigation did not reveal the area of origin. There were numerous
low burns everywhere. There was also numerous evidence of arcing in the
temporary wiring and elsewhere. This is not unusual. The close time proximity
between the electrical work and the fire suggests a relationship between
the two events. But there was nothing wrong with the installation. Further
investigation revealed the presence of an oxyacetylene torch with its tanks.
That facility was used to prepare and store food. Acetylene is not used
to prepare food and, therefore, its presence was intriguing and called for
an explanation. The owner was questioned. He also owned a garage. That is
a good reason to own that welding equipment. The next question was 'Why
did you have that equipment at the food plant?" With great embarrassment,
he explained that, to prevent the freezing of the water pipes, while the
temporary heating was being installed, he used the torch to heat the pipes.
The pipes were installed close to the walls that were finished with loose-fiber
That material may be ignited by a match in a matter of a few seconds.
If one blows out the flames, the material will sustain smoldering combustion
inside. The inside is red hot while the outside surface is black and charred.
That smoldering process proceeds at a speed of inches per hour and could
eventually lead to a flaming fire. The owner was told that the thawing process
is dangerous under the circumstances. He agreed and replied that, in fact,
he started fires on the wall a few times. But he was with his son. His son
had a bucket of water and quenched the flaming combustion a few times. Tests
showed that, under that condition, although the flames are extinguished,
smoldering combustion could continue inside.
Very clearly this fire was most probably caused by torch-thawing of water
pipes. The cause is known with a very reasonable degree of certainty while
the point of origin is unknown.
These two examples show clearly that, sometimes, the cause could be known
reasonable with a reasonable degree of certainty, even if the point of origin
is unknown. Numerous other examples could have been used.
The second example requires further comments. The owner of the building
who conducted the thawing process already knewor, at least, strongly
suspectedthe cause of the fire. In fact, he tried to hide the fact.
When he was asked if he had done anything dangerous that could have caused
the fire, he said no. However, when he became aware that the torch had been
found, he was clearly ill at ease. Obviously, the fire was not intentional.
The fire resulted from a dangerous process that was not conducted properly.
Numerous other examples of such fires could be discussed in which there
is already someone who suspects the cause because of some processes that
were performed. The perpetrator of the process will do everything he can
to avoid being pointed as responsible. It is human nature to be reluctant
to admit one's fault. The culprit is often determined by carefully investigating
the fire scene, looking for something unusual or out of place that calls
for some explanation. Often, the fire investigator does not even know specifically
what he is looking for. By being inquisitive, one sometimes may solve a
complex problem. In fact, the solution often looks very simple, once found.
Complex explanations for fire cause are often faulty. This author knows
of many fire cases in which there was already someone that knewor at
least suspectedthe cause of the fire. The above case is just one example.
The first case stresses the relation that often exists between a fire
and a dangerous act or process that happens in close time proximity with
the fire. The second example stresses the same point, but adds a word of
caution. That relation may not be unique. When something happens such as
the failure of the furnace, not only the electrician's work could have caused
the fire but other acts or processes could also have taken place.
It has often been stressed that one must determine the point of origin
of a fire before the cause could be established While that sequence is desirable,
it suffers many exceptions. Field cases were used to illustrate that it
is sometimes reasonable to establish a cause with a reasonable degree of
certainty, even if the point of origin is unknown.
About the Author
For the past 30 years, Dr. Béland has studied fires under laboratory
conditions and also at fire scenes. Many of the fires, including full size
fires in buildings, were started intentionally to study their behavior.
Dr. Béland specializes in the study of ignition, thermal transfer
and electrical causes. Many systems and devices were used in his experiments
to study their outcome and to determine what types of damage could be associated
with the causes that resulted in the fire. He has also experimented with
numerous systems to determine under which conditions they could constitute
Dr. Béland's research has resulted in the printing of over 100
technical articles in specialized journals such as: L'Ingenieur, Fire Technology,
Journal of Forensic Sciences, Fire & Arson Investigator, Power Apparatus
and Systems, Electrical Business, Proceedings of the Institute of Electrical
Engineers and others.
Dr. Béland has investigated over 900 fires and electrical failures
in which a total of 300 lives have been lost. He is retained by equipment
manufacturers, power companies and research centers. Dr. Béland has
done consulting work and lecturing in eight Canadian Provinces, 37 states
throughout the U.S., four European countries and New Zealand. He has served
as an expert witness in approximately 100 cases for numerous jurisdictions.
Dr. Béland has taught at numerous universities in Canada. He recently
retired from the Universite de Sherbrooke as a Professor in the Department
of Electrical Engineering. Dr. Béland is currently a private consultant
in his own firm.
Reprinted with permission.