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  • 1. Chapter 9 Reading Hazardous Energy
  • 2. Objectives
    • Define hazardous energy and list four ways to categorize its status
    • List common electrical equipment and their associated hazards
    • List the chemical properties of common utility gases
    • List the hazards associated with utility water and storm sewer systems
  • 3. Objectives (con’t.)
    • Give examples of mechanical hazardous energy
    • List the hazardous energy sources in vehicles
    • Discuss weather as hazardous energy and itemize the warning signs that extreme weather is approaching
    • Describe why water is a form of hazardous energy
  • 4. Defining Hazardous Energy
    • Hazardous energy
      • Stored potential energy that causes harm if suddenly released
    • ISO functions
      • Predict release
      • Analyze energy form and determine degree of impact
  • 5. Defining Hazardous Energy (con’t.)
    • ISO functions (con’t.)
      • Categorize the status of hazardous energy form
        • Stable – not likely to change
        • Stable – may change
        • Unstable – may require attention
        • Unstable – requires immediate attention
      • Intervene appropriately
  • 6. Figure 9-1 The ISO should be comfortable with electrical terms and be able to communicate hazards accurately. Forms of Hazardous Energy
  • 7. Forms of Hazardous Energy (con’t.)
    • Electricity
      • Integrity of systems based on proper grounding, insulation, and circuit protection
      • Local power company usually assists firefighters at incidents
      • ISO must understand electrical systems
        • Take no-cost seminars and workshops at local power company
  • 8. Figure 9-2 ISOs must be able to recognize the components of a typical municipal grid.
  • 9. Figure 9-3 Electrical components can present hazards to firefighters.
  • 10. Figure 9-4 This typical power pole arrangement is just one of the many possible.
  • 11. Forms of Hazardous Energy (con’t.)
    • Electricity (con’t.)
      • Seeks path of least resistance to ground
      • Ground gradient
        • Electrical energy that has established a path to the ground through the earth and continues to energize the earth
        • Example: downed power line can energize the earth in a concentric ring of up to 30 feet
  • 12. Table 9-1 Minimum distance requirements when working around electrical equipment.
  • 13. Forms of Hazardous Energy (con’t.)
    • Electricity (con’t.)
      • ISOs should evaluate the proximity and integrity of electrical systems
      • Exercise particular caution in:
        • Battery rooms: energized DC, wet batteries
        • Substation fires: transformer oil, pooled water, “reel coil”
  • 14. Forms of Hazardous Energy (con’t.)
    • Utility gas
      • Evaluate integrity of gas fuel supply and containment vessel
      • Excess pressure in components can cause pressure relief device to release expanding gas
      • Trauma can cause holes, pipe separation, or container failure
      • Escaped gas can accelerate fire, release toxins, and present explosion hazard
  • 15. Figure 9-5 The ISO who knows gas properties can more effectively assess risks associated with utilities.
  • 16. Forms of Hazardous Energy (con’t.)
    • Utility water and storm sewer systems
      • Uncontrolled water flow can cause initial and secondary collapse in structures
      • Damaged drain system can leak and undermine ground support
      • Pooled water in structures can extinguish pilot lights and release raw gas into water
      • Flash floods cause localize flooding and may trap victims into debris and grates
  • 17. Forms of Hazardous Energy (con’t.)
    • Mechanical energy
      • Includes pulleys, cables, counterweights, and springs
      • Sudden release of mechanical systems can be caused by heat, trauma, and /or overloading
        • Steel cable and “guy” wires can recoil with amazing force
      • Freestanding truss structures are weakened quickly when exposed to heat
        • Horizontal forces can accelerate collapse
  • 18. Forms of Hazardous Energy (con’t.)
    • Pressurized systems and vessels
      • Use hydraulics or pneumatics as a medium
      • Heat may increase pressure beyond design limits
      • Pressure relief system failure may result in component explosion
        • Component may act as a missile
        • The stronger the component, the more explosive it becomes when it fails
  • 19. Forms of Hazardous Energy (con’t.)
    • Hazardous energy in vehicles
      • Stability/position
        • Rolling weight, instability, collapse, ground support failure
      • Fuel systems
        • Fuel types, storage, pumps, fuel lines, pressurization
      • Electrical systems
        • Batteries, converters, high-voltage wires
  • 20. Forms of Hazardous Energy (con’t.)
    • Hazardous energy in vehicles (con’t.)
      • Power generation systems
        • Pulleys, belts, heat, noise, thrust, exhaust gases
      • Suspension/door systems
        • Springs, shocks, gas or pneumatic struts
      • Drive/brake systems
        • Pressure vessels, heat, springs, torsion, exotic metal fumes
  • 21. Forms of Hazardous Energy (con’t.)
    • Hazardous energy in vehicles (con’t.)
      • Restraint safety systems (air bags)
        • Trigger systems, chemicals
        • Delayed or unpredicted deployment can cause injury to rescuers (c-spine trauma, muscle sprain, contusions, and lacerations)
      • Alternative fuels and fuel systems have few standards and may resist fire control measures
      • High-voltage systems have large battery packs
  • 22. Forms of Hazardous Energy (con’t.)
    • Weather
      • Effective ISOs
        • Study weather and understand weather patterns in their geographical regions
        • Keep abreast of daily forecasts of weather observations as a matter of habit
  • 23. Forms of Hazardous Energy (con’t.)
    • Weather (con’t.)
      • Wind
        • Most important consideration
        • Strong or changing winds can affect firefighting operations in outside or structural fires
      • Humidity
        • Lower humidity means increased fire speed
        • High humidity affects firefighter health and smoke dissipation
  • 24. Forms of Hazardous Energy (con’t.)
    • Weather (con’t.)
      • Temperature
        • Evaluate relative to its effect on firefighter exposure
        • Acclimation is key!
      • Potential for change/storms
        • Watch the sky
        • Note 180-degree changes in wind direction for a short period of time
        • Be mindful of the potential for a flash flood
  • 25. Forms of Hazardous Energy (con’t.)
    • Weather (con’t.)
      • Potential for change/storms (con’t.)
        • Developing thunderstorms can produce rapid changes
        • At night, use lightning flashes to define cloud formations that may be tornadic
        • Calculate lightning distance: seconds between lightning flash and thunder divided by five
        • Deep snow makes travel difficult and can hide hazards
  • 26. Figure 9-6 Erratic wind shifts are common during thunderstorms. The ISO needs to watch weather influences during incidents.
  • 27. Forms of Hazardous Energy (con’t.)
    • Miscellaneous hazard energy forms
      • Earthen materials
      • Ice
      • Flowing water
      • Animal movement
        • Evacuation of penned, fire-threatened animals is amazingly dangerous
      • High-tech medical devices
        • Example: MRI equipment
  • 28. Summary
    • Hazardous energy
      • Stored potential that can cause harm if suddenly released
    • ISOs functions at hazardous energy incidents
      • Identify hazardous energy forms
      • Categorize potential impact on firefighters
  • 29. Summary (con’t.)
    • Forms of hazardous energy
      • Electricity
      • Utility gases
      • Water and storm systems
      • Mechanical energy
      • Pressurized vessels
      • Vehicle components
  • 30. Summary (con’t.)
    • Forms of hazardous energy (con’t.)
      • Weather
        • Wind
        • Temperature
        • Humidity
        • Potential for storms and rapid change
      • Animals