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THMG005 – Flammability

A fireball goes up at the site of an oil train derailment in Casselton, N.D., in this Dec. 30 photo. The fiery crash left an ominous cloud over the town and led some residents to evacuate.

In this episode we discuss flammability and response safety protocols when dealing with this hazard. We also talk about a few pertinent news articles from around the globe.

Complete Show Notes

5:00 TRACEM (Thermal, Radiological, Asphyxiation, Chemical, Etiological, Mechanical)

  • T stands for Thermal
  • Fire tetrahedron – heat, oxygen, fuel, and a “self-sustaining chemical reaction”
  • This “self-sustaining chemical reaction” is free of radical production, which is when a chemical bond is split or broken and produces energy to assist another reaction

6:45 Mechanics of Burning

  • When something is burning, the material isn’t what’s burning
  • The heat from the reaction is pumping into the material, causing it to vaporize
  • This vapor mixes with oxygen in the air and combusts, giving us fire
  • Vapor pressure – getting materials into the air
  • Volatility – how readily something goes into the atmosphere

8:30 Effects of Temperature on Flammability

  • Flammable – To be flammable, a substance must be less than 100 degrees Fahrenheit
  • Combustible – To be combustible, a substance must be more than 100 degrees Fahrenheit
  • The DOT recognizes 140 degrees as the threshold

10:40 Oxygen and Fuel

  • You need more than just oxygen and fuel to get something to burn
  • Lower (LEL) and upper (UEL) explosive limits – range in which things explode (wide ranges are very dangerous)
  • Rich and lean are very important to both occupational and safety aspects of hazmat
  • NIOSH Guide includes flammability ranges

16:20 Effects of Oxygen

  • Oxygen is one of the most reactive and dangerous substances out there – reacts with everything – fires, rust, etc.
  • Class 5 – considered an oxidizer (makes existing problems worse)

18:25 Flash Point

  • Flash point is a metric of how easy it is to ignite of a material as it evaporates into the atmosphere
  • Lower flash points indicate higher flammability
  • Rating Degree of Flammability Examples
    0 Materials that won’t burn Water
    1 Materials that must be preheated before they’ll ignite Lubricating oils and cooking oils
    2 Materials that must be moderately heated or exposed to relatively high ambient temperatures before they’ll ignite Diesel fuel
    3 Liquids and solids that can ignite under almost any temperature conditions Gasoline, acetone
    4 Materials that rapidly vaporize at atmospheric pressure and normal temperatures or are readily dispersed in the air and burn readily Natural gas, propane, butane

    20:05 Metering

    • David’s Lamp – if the flame got bigger, you were entering an area with higher flammability (used only in the early days)
    • Today, there are many meters to measure flammability, including COMB, toxic gas meters, and PID
    • Flammability is one of the first things first responders should rule out at a scene
    • PPE is a must
    • Meter tells us two things – whether something is present and how far you can go into the zone while staying safe

    24:10 Hazmat-Related News – Propane Leak in Massachusetts

    • Large propane vapor cloud hanging over a Massachusetts town
    • Caused when a utility worker left a valve open
    • Remember that propane vapors go down, so it’s important to notify hazmat authorities and make the public safe
    • On an awareness level, don’t mitigate – instead, perform defensive operations like mopping up liquids, suppressing vapors, damming, diverting, and dispersing
    • Use meter to determine explosive limits if you have one with you
    • It’s the technician’s job to stop or reduce the leak
    • Stopped by a driver, who turned off the valve and ended up suffering frostbite burns because the gas was extremely cold
    • Bunker gear isn’t suited for cold, so be very careful

    31:55 Hazmat-Related News – Brewery Leak in England

    • Chlorine dioxide (powdered brewery wash) leak – very caustic (base) substance
    • Acid burns are painful, while base burns make skin feel slimy
    • Chlorine dioxide is ideal for sanitizing after the cleaner has been rinsed – also removes compounds from water
    • Powerful DOT Class 5.1 and 5.6 oxidizer
    • On an awareness level, it’s important to inform the responsible party and help victims
    • On an operations level, it’s important to get in with full bunker gear and PPE and do an emergency technician
    • On a technician level, you’ll need chemical protective suits and your meter – flush the water with area and absorbent and ventilate the area

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