1. Chapter Eighteen Part I– Fire Investigations FRSC 8104 Criminalistics II Professor Bensley

2. FRSC 8104 – Chapter 18 Objectives After studying this chapter, the student should be able to:  Recognize the basic components required to have a fire  Understand how fire scene evidence is recognized, collected, and analyzed

3. FRSC 8104 – Chapter 18 Outline I.Fire Investigation Techniques - Introduction A.Why not the word arson? B.Types of Fuel 1.Gases 2.Liquids 3.Solids Simple Pyrolysis

4. FRSC 8104 – Chapter 18 Outline II.Physical Properties of Fuels A.Flammable B.Combustible C.Flash Point Flash Point Lab Apparatus

5. Flash Point of Butanol Normal butanol has a flash point in a closed cup of 29°C. It is therefore extremely flammable on a hot summer day when its vapors come in contact with a flame or spark.

6. FRSC 8104 – Chapter 18 Outline D.Flame Point E.Ignition Temperature Turpentine has an auto- ignition temperature of 253°C. Therefore, it will not burst into flame by itself at ambient temperature. Video of Flash Point, Flame Point, Ignition Temperature

7. FRSC 8104 – Chapter 18 Outline F.Explosive Limits Ethylene has a lower explosive limit of 2.7% and an upper limit of 36%. Therefore, in the presence of an ignition source, if the concentration of the gas is less than 2.7% or greater than 36%, there is no risk of explosion. But if the concentration of the substance is between these two limits, the mixture could explode. The concentration of the product in the air must be kept under its lower explosive limit, for example by using appropriate ventilation.

8. FRSC 8104 – Chapter 18 Outline G.Vapor Density H.Heat of Combustion (Heat Output) I.Flashover Flashover Videos: Controlled Environment Flashover http://abcnews.go.com/2020/video/arson-lab-tests-flashpoint-occurs-10590272

9. FRSC 8104 – Chapter 18 Outline III.Chemistry of Fire A.Three basic reactions B.Organic Compounds C.Elements of combustion (Fire Triangle or Fire Tetrahedron)

10. FRSC 8104 – Chapter 18 Outline IV.Introduction to Petroleum Products A.Light to Heavy Classification B.Classes (Types) 1.Natural Gas 2.LP Gas 3.Petroleum 4.Gasoline 5.Kerosene 6.Diesel Fuel 7.Fuel Oil 8.Lubricating Oils

11. FRSC 8104 – Chapter 18 Outline Fractional Distillation Tower

12. FRSC 8104 – Chapter 18 Outline V.At the Scene of a Fire (The Investigation) A.Purposes of Investigations B.Types of Fires 1.Natural, Accidental, Deliberate (Incendiary) 2.Classifying by Cause a.Direct Ignition b.Electrical c.Weather-Related d.Mechanical

13. FRSC 8104 – Chapter 18 Outline C.General Principles of Fire Behavior D.Fire Behavior Indicators 1.Burn Patterns

14. Another Classic V-Pattern The pattern is typical of an overheated appliance on the kitchen countertop. The arrow points to severely burned wallboard at the base of the V-pattern where a decomposed, plastic coffee pot housing was found, the apparent cause of the fire.

15. FRSC 8104 – Chapter 18 Outline 2.Heat Level (Heat Horizon) 3.Smoke Level (Smoke Horizon) 4.Low Burns 5.Spalling 6. Glass

16. 1000 mL Gasoline on Parquet Floor

17. 1000 mL Gasoline on Vinyl Floor

18. 1000 mL Kerosene on Parquet Floor

19. FRSC 8104 – Chapter 18 Outline E.Evidence Collection

20. FRSC 8104 – Chapter 18 Outline VI.Laboratory Analysis A.Extraction Methods 1.Solvent Extraction 2.Headspace

21. FRSC 8104 – Chapter 18 Outline 3.Steam Distillation 4.Purge and Trap (Charcoal Tube) 5.Passive Headspace Diffusion (Charcoal Strips) Purge and Trap Schematic

22. FRSC 8104 – Chapter 18 Outline B.Analytical Techniques 1.FTIR (Rare) 2.TLC for dyes 3.UV-Vis (Rare) 4.GC/FID 5.GC/MS a.GC/MS/MS

23. Gasoline Chromatogram

24. Weathered Gasoline

25. BTEX in Gasoline

26. Gasoline Chromatogram

27. Diesel Fuel Chromatogram

28. FRSC 8104 – Chapter 18 Outline VII.ASTM Classification System (2002) A.ASTM E-1618 1.Gasoline 2.Petroleum Distillates 3.Isoparaffinic Products 4.Aromatic Products 5.Napthenic paraffinic products 6.n-Alkanes 7.De-aromatized Distillates 8.Oxygenated Solvents 9.Others – Misc.

29. FRSC 8104 – Chapter 18 Outline VIII.MS Characteristic Peaks A.Pristane and Phytane B.Other Compounds C.Gasoline Target Compounds