This chapter discusses identifying and mitigating hazardous energy sources that firefighters may encounter. It defines hazardous energy and categorizes it as stable or unstable. It then describes various hazardous energy sources such as electricity from power lines, substations, wind turbines, and alternative energy sources. It also discusses utility gas lines, water and storm systems, mechanical systems, pressurized vessels, vehicles, weather, and miscellaneous hazards. The chapter outlines methods to prevent injury from these hazards through awareness, zoning hazardous areas, lock-out/tag-out procedures, and protective cooling of pressurized vessels and systems.

1. Fire Department Incident Safety
Officer
Third Edition
Chapter 8 — Reading Hazardous Energy

2. Knowledge Objectives (1 of 2)
‣ Describe potential hazardous energy sources that could be
present at an incident.
‣ Identify the methods used to determine the presence of
potential hazardous energy sources.
‣ State the methods used to communicate the presence or
absence of potential hazardous energy sources.
‣ Describe the methods used to establish and mark hazard
zones necessary to protect members from potential
hazardous energy sources.
‣ Identify the major components of an electrical grid system.

3. Knowledge Objectives (2 of 2)
‣ List forms of alternative energy and their associated
hazards.
‣ List the chemical properties of common utility gases.
‣ List the hazards associated with utility water and storm
sewer systems.
‣ Describe examples of mechanical hazardous energy.
‣ List the hazardous energy sources in vehicles.
‣ Discuss weather as hazardous energy and list the warning
signs that extreme weather is approaching.

4. Introduction: Defining Hazardous
Energy (1 of 2)
‣ Definitions
‣ Context of this text
‣ Unintended, and often sudden, release of stored,
residual, or potential energy that will cause harm
‣ NFPA definition
‣ Electrical, mechanical, hydraulic, pneumatic, nuclear,
thermal, gravitational, or any other form of energy that
could cause injury due to the unintended motion
energizing, start-up, or release of such stored or
residual energy in machinery, equipment, piping,
pipelines or process systems

5. ‣ Understanding hazardous energy sources
‣ An effective ISO further categorizes energy as stable and
unstable based on the future potential of the energy
‣ Stable: not likely to change
‣ Stable: may change
‣ Unstable: may require attention
‣ Unstable: requires immediate attention
Introduction: Defining Hazardous
Energy (2 of 2)

6. Electricity (1 of 11)
‣ Integrity of electrical systems
‣ Grounded, insulated, and circuit protected
‣ Solving problem without local power companies is rare
‣ A basic understanding of electrical system integrity is
important

7. Electricity (2 of 11)

8. ‣ General electrical hazards
‣ Tell-tale signs of electrical problems (shock potential):
‣ Odor of overheated wires (plastic melting and/or
burning oil)
‣ Visible smoke or haze emitting from electrical
equipment and wires
‣ A “buzzing” sound coming from wires or transformers
‣ Tingling sensations in feet
‣ Tingling or static sensations around the face or hands
‣ Metallic materials with discoloring or blistering paint or
that are glowing
Electricity (3 of 11)

9. ‣ General electrical hazards
‣ Steps to protect against electrical hazards
‣ Treat all downed power lines as if they are energized
‣ Keep a safe distance from downed power lines
‣ Wear the appropriate personal protective clothing and
footwear
‣ Do not attempt to move or cut downed wires
‣ Avoid walking or standing in pooled water
‣ Never apply water directly to electrical equipment that
is burning or arcing
Electricity (4 of 11)

10. ‣ Distribution grid components
Electricity (5 of 11)

11. ‣ Overhead power
distribution setup
Electricity (6 of 11)

12. ‣ Substation fires
‣ May burn for several days
‣ Heat generated from an oil-fed fire can cause serious
damage to the high-tension wire infrastructure and other
transformers
‣ Takes copious amounts of water to bring the transformer
core down below 400°F
Electricity (7 of 11)

13. ‣ Incidents involving wind turbine
power generators
‣ Rotating blades
‣ Nacelles containing moving
gears and systems
‣ Toxic smoke from burning
turbines
Courtesy of David Dodson
Electricity (8 of 11)

14. ‣ Building (user) electrical components
‣ Grid feed and main
‣ Power distribution circuit protection
‣ Transformer(s)
‣ Wiring
‣ Outlets, fixtures, and switch boxes
Electricity (9 of 11)

15. ‣ Alternative energy sources
‣ Buildings of all types and sizes
‣ “Green” movement
‣ Battery rooms
‣ Emergency backup generators
Electricity (10 of 11)

16. ‣ Alternative energy sources
‣ Solar energy
‣ PV solar systems
‣ Solar thermal systems
Electricity (11 of 11)

17. Utility Gas
‣ Propane and natural gas (methane)
‣ Colorless and odorless in their natural form
‣ Can be stored in a liquid state
‣ Flame impingement on LPG and LNG storage vessels is
extraordinarily dangerous
‣ Tank cooling is mandatory to prevent BLEVE
‣ If tank cooling is not possible, all personnel must be
evacuated

18. Utility Water, Storm Sewer Systems, and
Flash Floods
‣ Water hazards
‣ Sinkholes
‣ Initial and secondary collapses in structures
‣ Firefighting efforts
‣ Water can extinguish gas-fired pilot lights
‣ Pooled water and electrical equipment
‣ Flash floods

19. Mechanical Energy
‣ Examples of mechanical stored energy
‣ Pulleys, cables, conveyers, counterweights, and springs
‣ Lightweight high-rack storage systems
‣ Dead or live loads and gravity
‣ Sudden release of mechanical systems
‣ Heat
‣ Trauma
‣ Overloading
‣ Combination

20. Pressurized Systems and Vessels
‣ Use a medium to achieve power or force
‣ Hydraulics (liquids)
‣ Pneumatics (air/gases)
‣ Closed containers
‣ Become “pressure vessels” when heated by fire or hot
smoke
‣ Failure of the container can cause it to explode
‣ May become a missile
‣ Stored liquid may boil over and spill

21. Hazardous Energy in Vehicles (1 of 3)
‣ Factors that can contribute to hazardous energy
‣ Stability/position
‣ Fuel systems
‣ Electrical systems
‣ Power generation systems
‣ Suspension/door systems
‣ Drive/brake systems
‣ Restraint safety systems (air bags)

22. ‣ Specific systems and hazards
‣ Alternative fuel and energy systems
‣ Drive brake systems: tractors/trailers
‣ Air brake chambers are likely to fail
‣ Heavy-duty spring within the chamber can become a
projectile
‣ Protective cooling of air chambers and wheel rims is
paramount
‣ Restraint safety systems: air bags
‣ Accidental or delayed deployment of air restraint
devices can cause injury
Hazardous Energy in Vehicles (2 of 3)

23. ‣ Specific systems and hazards (cont.)
‣ Locomotives
‣ Modern train locomotives are actually very large
electrical generators
‣ Steam locomotive hazards include scalding
liquid/vapors, explosive ruptures, and uncontained fuel
fires
‣ Aircraft
‣ Radar
‣ Exotic metals
‣ Potential on munitions in military and covert-mission
aircraft
Hazardous Energy in Vehicles (3 of 3)

24. Weather (1 of 3)
‣ Effective ISOs study weather and understand the particulars of
weather patterns
‣ Daily forecasts and weather observations
‣ Wind
‣ ISOs should understand the wind patterns for their specific
geographic region
‣ As wind velocity increases, so does the risk to firefighters

25. ‣ Humidity
‣ Affects firefighters in a number of ways
‣ High humidity affects structural fires by keeping smoke
from dissipating into the outside air
‣ Prolonged low humidity can cause accelerated fire spread in
lumber and other wood products
Weather (2 of 3)

26. ‣ Temperature
‣ Temperature needs to be evaluated relative to its effect on
firefighter exposure
‣ Weather shifts
‣ The ISO familiar with local weather tendencies can advise
the IC of weather indicators that may require a shift in the
incident action plan
Weather (3 of 3)

27. Miscellaneous Hazardous Energy Forms
‣ Miscellaneous hazards
‣ Earthen materials
‣ Ice
‣ Flowing water
‣ Animals
‣ Medical care facilities
‣ Chemicals
‣ Magnetic resonance imaging (MRI) equipment
‣ Medical X-ray imaging

28. Preventing Actions for Hazardous
Energy (1 of 6)
‣ Awareness — Communication
‣ The first action or priority
‣ Urgent or priority radio message
‣ Type and location of hazard
‣ What personnel or activities need to be withdrawn
‣ Less-urgent methods
‣ Face-to-face interaction
‣ General safety messages or briefings
‣ IC information sharing
‣ Flagging to draw attention to the threat

29. ‣ Avoidance — Zoning
‣ Second priority preventive action
‣ Four types of control zones
‣ No-entry zone: where no responders are allowed to
enter
‣ Hot zone: immediately surrounding a hazardous area;
considered immediately dangerous to life and health
(IDLH)
‣ Warm zone: area surrounding a hot zone; where
personnel, equipment, and apparatus are operating
‣ Cold zone: area surrounding the warm zone
Preventing Actions for Hazardous
Energy (2 of 6)

30. ‣ Avoidance — Zoning (cont.)
‣ Barrier tape
‣ No-entry zone: Red
and white diagonal-
striped or chevron
‣ Hot zone: Red
‣ Warm zone: Yellow
‣ Cold zone: Green
Courtesy of David Dodson
Preventing Actions for Hazardous
Energy (3 of 6)

31. ‣ Avoidance — Zoning (cont.)
‣ Factors for control zone sizes/distances
‣ Height of something that may collapse
‣ Wind direction and speed
‣ Product flammability and potential for a BLEVE
‣ Percussive unconfined vapor cloud explosion (PUVCE)
‣ Length of cable or wire and the direction of recoil
‣ Potential for a domino effect
‣ Direction, volume, and speed of liquid
‣ Presence of protective barriers
‣ Electrical hazards
Preventing Actions for Hazardous
Energy (4 of 6)

32. ‣ Lock-out/tag-out
‣ Lockout/tag-out safeguards
‣ Electricity remains off
‣ Valves, switches, and other initiating devices remain in
an off or closed position
‣ Usually includes the application of a lock and a warning
tag
‣ Posting a sentry can help deter others from turning
something on
Preventing Actions for Hazardous
Energy (5 of 6)

33. ‣ Protective cooling
‣ Susceptible to rupture when exposed to external heat and
flame impingement
‣ Pressure vessels
‣ Conveyance systems
‣ Closed-loop or sealed hazardous energy systems
‣ Be aware of additional hazards
‣ Water reactivity
‣ Electrical conduction
‣ Pooling
Preventing Actions for Hazardous
Energy (6 of 6)