Fire Investigation and Detection of Arson .
Introduction:
Thorough investigation of fire is an integral part of the fire department’s commitment to Public safety.
Fire investigation includes two areas:
a) Fire cause determination.
b) Investigations of criminal actions which may have contributed to a fire.
Fire cause determinations through investigation is of major importance to a fire prevention programme. Analyses of the cause of the fire within the community is the basis for establishing fire prevention programme priorities and providing fire safety information to the public. If it is determined that a fire is caused by arson or other unlawful burning of property, a full criminal investigation should be conducted.
50 considering ever increasing loss of property, financial disaster, physical injury and death caused by fire to many innocent persons each year, it is the duty of the fire department to persevere in the enquiry into the cause of every fire with three objects in views.
a) If the fire is due to some dangerous industrial process or operation or storage, to allow authority to devise safety measures or precautions to prevent a re occurrence.
b) If due to carelessness, ignorance, or neglect, to bring the cause to light thus
obviating a re-occurrence.
c) If the fire has been maliciously started, to detect the offender and prevent him from repeating his crime.
The need for the professional approach to fire investigation and accurate presentation of facts should be the aim of every fire officer. Such investigation is a highly skilled and often a difficult task calling for great experience.
2. Initial observations The cause of outbreak of fire is probably the last thing in mind of the officers of the first attendance at a major fire, the uppermosts are rescue, fire fighting, water supply arrangements, reinforcement etc. However, initial observations and actions on arrival and during fire tighting can assist greatly in later investigation.
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2.Observing the fire scene:
a) The extent of the fire - Where is the fire showing, on how many
floors, how much of the
building is involved?
b) Direction of the fire travel - Is the fire traveling horizontally or vertically?
c) Abnormally rapid spread of fire-
This could indicate combustible linings and interior contents of a highly combustible nature. However, in a premises with low fire loading, rapid fire spread may indicate the use of accelerants.
d) Colour and odour of smoke -.and flame -
Unusual and abnormal colours of flame and smoke in a normal fire, particularly if a distinctive odours is apparent, should lead to suspect the presence of an accelerant and therefore a possibility of malicious attempt may arise.
e) Doors and windows open -
Evidence of doors and windows being propelled open throughout the interior of premises in odd hours to create a flue situation may indicate malicious intension to spread the fire to other areas.
f) Signs of forced entry -
Broken padlocks, splintered jambs around the securing devices on exterior doors are obvious signs of forced entry if this was not done by fire fighting staff.
g) Multiplicity of fires -
Several seats of fire and fire showing at window openings remote from each other on arrival should give the fire officer reason to suspects abnormal circumstances.
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3) Logical Approach:
The process of investigation will start when the officer arrives at the fire scene. Logical approach towards fire investigation covers the following:
a) Interviewing the witnesses.
b) Site investigation.
A. Interviewing the witnesses:
The following witnesses may be interviewed while determining the cause of fire:
i) Who have knowledge of the development of fire before arrival of the brigade-occupier, security and control room staff etc.
ii) Who have knowledge about spread of fire and who fought fire-fire staff.
iii) Who have knowledge about the risk inherent in the building-management, employee etc.
iv) Who have knowledge about the service of the building-electrical authority, gas undertakings, etc.
The following areas must be covered while questioning or talking to witness to ascertain the cause of fire.
a) Where was the fire first seen and when?
b) Was the fire travelling horizontally, verticaily or downward? c) Was there smoke only, or also flame?
d) Did the fire spread abnormally rapidly? e) Were the doors open?
f) Were any windows, doors broken or was there any sign of forced entry?
g) Was there any further development -explosions, collapse etc. before the brigade arrived?
h) Did anyone see colour of the smoke and flame, smell or hear any thing unusual or abnormal?
i) Was any machinery left switched on?
j) Was any repair work, decoration, or other non-everyday activity in progress?
k) Were there several fires in the same building at a time?
l) Were any strangers seen in the vicinity?
The following general information about the building is also necessary through questioning:
i) Is there any machinery which might cause Spark?
ii) Is there any evidence of equipment or installations not properly maintained?
iii) Are there any dangerous substances (explosives, highly flammable goods)
stored or processed?
iv) What are the nominal procedures for waste disposal?
v) Is there any evidence of carelessness or neglect, or can anyone quote examples?
vi) Have there been previous fires, or electrical or other faults at the premises?
vii) Were the Services (electricity, gas etc) on or off?
B. Site Investigation:
The information obtained on interviewing different persons as stated above as
well as the officer’s own observations may not be sufficient to ascertain the actual cause of fire. It is also required to search for physical evidence on the site itself.
The following points should be considered while investigating the site:
1 The point of ignition -Where it started? 2 The time of ignition When it started?
3 The cause of ignition How it started?
A.Establishing the point of Ignition:
The requirement in assessing the cause of fire will be to establish where it started. To achieve this the following points should be considered:
i) Which part of the building was involved and when the fire was first noticed.
ii) Particular window or similar openings where flame was fist noticed not smoke.
iii) Lowest part of the building involved in fire.
iv)Part of the building having excessive smoke staining -pattern of smoke staining is always differing from the pattern of fire spread.
v) Pattern of fire spread whether the fire traveled in-side the room to out. side or vice-versa.
Important points of observation are:
1) Condition of the wall plaster.
2) Condition of the door frame.
3) Blistering of paints of doors and windows.
4) Discoloration of glass panel.
vi) Part of the building having signs of severest burning, specially roof structure.
vii) Whether fire developed quickly or slowly in its early stage.
It is important to mention that the behavior of some materials generally used in the building in fire condition can assist in determining the maximum temperature reached in a particular fire.
•There are various indications of slow or quick growth of fire:
1.Glass (window, mirror) When fire growth is rapid, glass generally shows clean breaks following the line of frame; when it is slow, the glass does not break but appears crazed with little or no staining.
2.Plaster In quick built-up, heat causes the plaster to fall from wall, while in slow buiIt-up the plaster will probably remain in place. Ceiling plaster does not usually fall as a result of heating.
3.Degree of burning When the degree of burning is not uniform, it usually indicates a slow rate of growth of fire.
B. Establishing time of ignition:
The time of ignition can also be a clue to the cause of fire. The following points can give an idea about this:
i) Time of failure of electric light or electric clock.
ii) Time of starting any detection device or sprinkler.
iii) Intensity and extent of fire when first noticed.
iv) Cries of the live stocks.
v) Report of an explosion.
vi) Weather condition.
It is interesting to mention that charring of timber in a building which has been on fire can help to indicate when fire started. The rate of charring of timber varies from 30mm to 50mm per hour according to species. Rapid fire and very high temperature do increase these burning rates. Tests have shown that wood ignites in 5 minutes at 320°C and in 30 minutes at 190°C.
C. Establishing the cause of fire:
There are many possible sources of ignition. Some of such ignition sources are listed below. Though difficult, the probable cause of the fire can be determined through the process of elimination and standing on the circumstantial evidences.
1) Electric origin (overloading, sparks, short circuit, static discharge, failure
of switch gear, lighting).
2)Careless disposal of smoking materials.
3) Gas leak.
4) Open flame/open heating.
5) Defective or overheating bearing machinery.
6) Chemical reaction.
7) Deliberately setting fire e.g. arson.
8) Spontaneous combustion.
9) Explosion.
10) Pyrophoric action.
11) Fire works.
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4. Detection of Arson
In general terms, arson is the deliberate and malicious destruction or damaging of property by fire. There are a number of reasons which might arouse suspicion, some very strongly, that arson is the probable cause of fire. The reasons for suspecting arson are as follows:
A) Several seats of fires almost simultaneously in the same premises.
B) Signs of use of an accelerant; unusual smell such as kerosene oil, petrol etc.
C) Presence of unusual and unexpected substances, not normally used in the
premises, such as candle, open lamp etc.
D) Signs of forced entry or doors and windows unexpectedly open.
E) Unusual location of the seat of fire and unlikely pattern of fire spread.
F) A small fire only destroying valuable records, accounts, insurance papers etc.
G) Apparent attempts to conceal the crime.
H) Fire in the stock of poor quality goods, where owner suggests that of good quality.
I) Encouraged growth of fire and hindered extinguishment, i.e. item moved to block window, fire door left open etc.
J) Livestocks or other animal have been released prior to start of fire.
K) Unusual sounds such as explosion.
L) Alarm, sprinkler etc. turned off or made inoperative.
M) The same person is seen at more than one fire even in odd hours and behaving suspiciously.
Many people set on fire to the property motivated by many different reasons. The motivated arson cases may be classified into two groups.
A) Arson without motive:
a) Vandalism:
Vandals, who might on other occasions use other methods, may use fire merely as a convenient tool with which to damage properly.
b) Pyromaniacs, week minded persons:
A number of people are driven to set fires by their mental disorder. They do not know what they are doing.
c) Ideology:
Racial, religious, and political motives may inspire arson, either as a direct attack on an opposition group or to threat or to gain publicity.
d) Self-glorification:
A person may start fire to gain some sort of distinction by being the one to discover the fire and start fighting it.
B) Arson with a motive:
a) Employees under notice of suspension/dismissal, evicted tenant, officials passed over for promotion etc. who have grievance against their employer, landlord etc.
b) Jealousy against the owner of the property and wishing to get revenge.
c) Fraud against an insurance company, for example, to destroy low quality goods but claim recompense for goods of high value.
d) Destruction of evidence of a more serious crime-murder, robbery etc.
e) Terrorism-incendiarism.
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