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Chapter 04


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Chapter 04

  1. 1. Hazardous Materials for First Responders 4 th Edition Chapter 4 — Chemical Properties and Hazardous Materials Behavior
  2. 2. <ul><li>Need to know a materials behavior as well as symptoms and effects of exposure </li></ul><ul><li>Determines behavior </li></ul>Physical Properties 4 –
  3. 3. States of Matter <ul><li>Gas </li></ul><ul><li>Liquid </li></ul><ul><li>Solid </li></ul>4 –
  4. 4. Gas, tends to expand indefinitely. 4 –
  5. 5. Liquid, may give off vapors. 4 –
  6. 6. Solid, often stays in place unless acted upon. 4 –
  7. 7. <ul><li>Dust - Solid formed by reducing the size (mechanically) of organic or inorganic solid materials. </li></ul><ul><li>Fume – Particles that form when a vapor state solid condenses in cool air (most will form a oxide) </li></ul><ul><li>Mist – Finely divided liquid </li></ul><ul><li>Aerosol – Similar to a mist but smaller , highly respirable </li></ul><ul><li>Fiber – Solid particle whose length is greater than it’s diameter </li></ul><ul><li>Vapor – Gaseous form of a substance that is normally a solid or liquid at room temperature and pressure </li></ul>Industry Terms 4 –
  8. 8. Flammability <ul><li>Majority of haz mat incidents </li></ul>4 –
  9. 9. Flammability depends on three properties. 4 –
  10. 10. Flash point is the temperature at which there are sufficient vapors to ignite, but not sustain combustion. 4 –
  11. 11. <ul><li>Fire point- temp. at which enough vapors are given off to support continuous burning(slightly higher than flash point) </li></ul><ul><li>Liquids do not burn </li></ul><ul><li>Flammable gases have no flash point (already in the gaseous state) </li></ul>Flash point 4 –
  12. 12. <ul><li>Everyday use they mean the same thing </li></ul><ul><li>Inflammable = flammable not nonflammable </li></ul><ul><li>Low flash point = flammable </li></ul><ul><li>High flash point = combustible </li></ul><ul><li>Each agency uses different criteria </li></ul><ul><li>DOT - 141°f or less flam. Greater than 141° comb. </li></ul><ul><li>OSHA/NFPA – less than 100°f is flam. Greater than 100° is comb. </li></ul>Flammable or Combustible 4 –
  13. 13. Autoignition temperature is the level to which the fuel in air must be heated to initiate self-sustained combustion. 4 –
  14. 14. <ul><li>The point at which a fuel spontaneously ignites (usually higher than flash or fire point) </li></ul><ul><li>Often used synonymously with ignition temperature, or autoignition point </li></ul><ul><li>NFPA – Ignition temp. = min. temp. required to initiate or cause self-sustained combustion independent of the heating or heated element. </li></ul><ul><li>Autoignition temp. = the temp. at which a mixture will spontaneously ignite </li></ul>Autoignition Temperature 4 –
  15. 15. <ul><li>Percentage of gas or vapor concentration in the air that will burn or explode if ignited </li></ul><ul><li>Expressed as LEL </li></ul>Explosive limits 4 –
  16. 16. The flammable, explosive, or combustible range helps to establish the lower and upper explosive limits. 4 –
  17. 17. Vapor Pressure <ul><li>Pressure exerted by a saturated vapor above it’s own liquid in a closed container or pressure produced or exerted by the vapors released by a liquid </li></ul><ul><li>The higher the temperature of a substance the higher the vapor pressure will be </li></ul><ul><li>Vapor pressure can be used as a gauge to determine how fast a product will evaporate </li></ul>4 –
  18. 18. Vapor Pressure 4 – Expressed in: psi, kPa, bars, mmHg, or atm
  19. 19. <ul><li>Temperature at which the vapor pressure of a liquid is equal to or greater than atmospheric pressure </li></ul><ul><li>Temperature at which a liquid changes to a gas </li></ul><ul><li>Usually expressed in degrees Fahrenheit (Celsius) at sea level air pressure </li></ul>Boiling Point 4 –
  20. 20. Boiling liquid expanding vapor explosion (BLEVE) can occur when liquid in a container is heated. 4 –
  21. 21. Melting Point, Freezing Point, Sublimation 4 –
  22. 22. Melting and freezing point definitions are based on normal atmospheric pressure. 4 –
  23. 23. Sublimation is a change from solid to gas state without going into a liquid state. 4 –
  24. 24. Vapor density is the weight of gases compared to the same volume of air at similar temperature and pressure. 4 –
  25. 25. Vapor Density <ul><li>Majority of gases have a vapor density greater than 1 </li></ul><ul><li>Light gases rise and dissipate </li></ul><ul><li>Heavy gases concentrate in low places </li></ul><ul><li>Topography, weather and mixture easily affect vapors </li></ul>4 –
  26. 26. Solubility/Miscibility 4 –
  27. 27. Solubility is useful in determining spill clean up methods and extinguishing agents. 4 –
  28. 28. <ul><li>Negligible (insoluble) – less than 0.1% dissolved in water </li></ul><ul><li>Slight (slight soluble) – percent's from 0.1 to 1 dissolved in water </li></ul><ul><li>Moderate (moderately soluble) – percent’s from 1 to 10 dissolved in water </li></ul><ul><li>Appreciable (partly soluble) – more than 10 to 25 percent dissolved in water </li></ul><ul><li>Completely (soluble) – percent’s from 25 to 100 percent dissolved in water </li></ul>Degrees of Solubility 4 –
  29. 29. Miscibility impacts how two or more gases or liquids mix with or dissolve into each other. 4 – Water and oil are immiscible, so they do not mix. Courtesy of U.S. Coast Guard
  30. 30. Specific Gravity <ul><li>Ratio of density of a material to the density of a standard material at a standard pressure and temperature </li></ul><ul><li>Or the weight of a substance compared to an equal volume of water </li></ul><ul><li>Specific gravity less than 1 floats, greater than 1 sinks </li></ul>4 –
  31. 31. Specific gravity is directly influenced by solubility. 4 –
  32. 32. Persistence 4 –
  33. 33. Persistence is a chemical’s ability to remain in an environment. 4 –
  34. 34. Reactivity <ul><li>Referred to in the industrial world as reactive materials, will commonly react vigorously or violently with air , water , heat, light, each other or other materials </li></ul>4 –
  35. 35. Reactivity is the relative ability to undergo a chemical reaction with another material. 4 – (Continued)
  36. 36. The reactivity triangle explains the basic components of many chemical reactions. 4 – (Continued)
  37. 37. Reactivity can be effected by polymerization and inhibitors. 4 –
  38. 38. <ul><li>Base assessment on these questions: </li></ul><ul><li>How long will this exposure exist? </li></ul><ul><li>What has stressed the container? </li></ul><ul><li>How will the container and material behave? </li></ul><ul><li>What are the harmful effects of the container’s material? </li></ul>General Hazardous Materials Behavior Model (GEBMO) 4 –
  39. 39. GEBMO defines hazardous materials and explains common elements of haz mat incidents. 4 –
  40. 40. GEBMO describes the general sequence of events for hazardous materials incidents. 4 –
  41. 41. Stress is stimulus causing strain, pressure, or deformity. Haz Mat for First Responders 4 –
  42. 42. Breach occurs when a container is stressed beyond limits of recovery. 4 –
  43. 43. <ul><li>Disintegration </li></ul><ul><li>Runaway cracking </li></ul><ul><li>Attachments open or break </li></ul><ul><li>Puncture </li></ul><ul><li>Split or tear </li></ul><ul><li>Metal reduction </li></ul>Types of Breaches 4 – Courtesy of Phil Linder
  44. 44. Release can be product, energy, or parts of the container. 4 – Courtesy of U.S. U.S. Army, photo by Sgt. Jabob H.Smith
  45. 45. The dispersion/engulf distribution occurs according to five factors. 4 –
  46. 46. A hemispheric dispersion pattern generally results from a rapid release. 4 – (Continued)
  47. 47. A cloud dispersion pattern occurs when the material has collectively risen above the ground or water. 4 – (Continued)
  48. 48. The plume dispersion pattern is affected by vapor density, terrain, and wind speed/direction. 4 – (Continued)
  49. 49. The cone dispersion pattern has a wide base downrange of the breach. 4 – (Continued)
  50. 50. The stream dispersion pattern is affected by gravity and topographical contours. 4 – (Continued)
  51. 51. The pool dispersion pattern is created by a three-dimensional, slow flowing liquid. 4 – (Continued)
  52. 52. Irregular dispersion patterns can result from contaminated vehicles or responders. 4 –
  53. 53. Exposure/contact can effect people, environment, and property in a variety of timeframes. 4 –
  54. 54. Harm can be generated by a variety of health and physical hazards.
  55. 55. Summary <ul><li>First responders need the ability to predict how a hazardous material will behave when it escapes its container. </li></ul><ul><li>The behavior is often determined by the material’s physical properties. </li></ul>4 –