Fire investigation mythswith pictures

Fire Investigation Myths and Fire Investigator Responsibilities

Tom Bohm, Fire MarshalHermiston Fire and Emergency Services

Char /Alligatoring

Myth #1 Depth of Char / Alligatoring

•Myth – An investigator could estimate how long the fire burned by the depth of the char

•Truth- Charring shows time or intensity – Low intense fire/long duration may have the same char pattern as a high intense pattern/short duration

•Use char as an indictor of fire travel

Myth #1 Depth of Char / Alligatoring

•Myth - Alligatoring- if the blisters were large and shiny a sign of ignitable liquid was used

•Truth- There is no significance to alligatoring

Spalling

Myth #2 Spalling

•Myth- Spalling in concrete means ignitable liquids were used

•Truth – the area beneath a puddle of liquid, even ignitable liquids, will be cooler than adjacent exposed surfaces during a fire

Annealed bed or furniture springs

Myth #3 Annealed Bed or Furniture Springs

•Myth- Caused by a long duration smoldering event- cigarette in a sofa

•Truth- Short duration exposure of over 750° F causes annealing

•Can be used to quantitate fire flow and intensity

Ignitable liquid / pour pattern

Myth #4 Ignitable Liquids/ Pour Patterns

•Myth – Narrow or irregular burn patterns on the floor are reliable signs of an ignitable liquid

•Truth- not reliable in post flashover fires or in drop down fires

•Worn carpet areas may show a pattern•Furniture padding may melt

Myth #5 Spontaneous Combustion

•Myth- Stain rags in a pile will spontaneously combust

•Truth- pile has to be just right- too tight and no oxygen and to loose heat dissipates

•Remember – these stain give off ignitable vapors

Myth #6 Electrical Fires

•Myth- the absence of tangible proof of an incendiary fire indicates electrical caused fire

•Truth- Sometimes you just have to say the fire is ruled accidental and the cause is undetermined and then state why

Myth #7- Fire are Ruled Arson or Suspicious

•Myth - The fire is ruled arson or suspicious

•Truth- Arson is a crime – no one has been convicted

•Truth- No fire is suspicious – suspicious is a level of proof not a classification of cause- only accidental, incendiary , natural or undetermined

Windows

Myth #8 Windows

•Myth – greasy windows indicate a petroleum product was used

•Truth- greasy windows mean nothing

•Myth- Crazing of glass proves rapid, intense fire

•Truth- proves rapid cooling- crazing can occur with a 140° F temperature change or difference

Smoke Patterns

Myth #8 Color of Smoke/ Intense Fast Fires

• Myth- Black smoke means a petroleum based ignitable liquid was used

• Truth – Not a reliable indicator

• Myth- Fast fires are caused by ignitable liquids• Truth- 1977- it took 17 minutes from the

sounding of the smoke alarm to flashover, In 2009 – 3 minutes - • Wood and gasoline burn at same flame

temperature

Tripped electrical breakers

Myth #8 Tripped electrical breakers

•Myth- Tripped breaker meant an electrical fire

•Truth- Tripped breaker may mean temperatures at panel at over 400° F for over 20 minutes

Myth #9 Burn Patterns

•Myth- Charring on the bottom of the door indicates ignitable liquid was used

Truth- This usually happens when the door is closed and hot gasses escape

Is Fire Investigation “Junk Science”

•Myth- what I was told in 1977 by fire investigators is it true today

•Truth- most fire investigators at that time used experience and what other older fire investigators said for their fire investigation methodology and theories

•Truth- Fires can be inconsistent – too many variables, wind, humidity, size of room, oxygen, ceiling height, fuel load

How to Improve Fire Investigations

• Training▫ NFPA 921▫ National Fire Academy▫ IAAI

• Certification▫ NFPA certification through DPSST▫ CFI through the IAAI

• Use a systematic approach to fire investigation everytime▫ Pictures▫ Sketches▫ Outside to inside, least burned to most burned fire

investigation method – everytime▫ Document, Document, Document

How to Improve Fire Investigations

•You need to rule in as well as rule out•Not one single indicator can be taken at

face value without considering other factors

•Unless you are certain – the fire is undetermined

•Do not make your investigation fit your theory

•To be classified incendiary it must be “ beyond a reasonable doubt of fire investigator certainty”

Basic Responsibilities for Fire Investigations

• Understand- that by state law fire departments are responsible to investigate every fire

Depositions are not FUN

Know▫NFPA 921- Guide for Fire and Explosion Investigation▫Amendment IV – unreasonable search and seizure▫Amendment V – Due process of law▫Amendment VI – Speedy trial, counsel

Basic Responsibilities for Fire Investigations

•Michigan v. Tyler – reasonable period of time

•Michigan v. Clifford- search warrant•Fire investigators- interview•Spoliation of evidence•Chain of custody•Documentation•Types of evidence – Demonstrative,

Photograph/Illustrative, and Testimonial

Basic Responsibilities for Fire Investigations

•Testimonial Evidence-▫Fact witness▫Expert witness

Federal rules of evidence Daubert v. Merrell Dow