This document discusses utility emergencies involving electricity, natural gas, and propane. It provides information on electrical distribution systems, hazards of downed power lines, pole/transformer fires, vehicle accidents involving poles, and manhole fires. Guidelines are given for establishing safety zones, contacting utility companies, and safely responding to various emergency scenarios until utilities personnel arrive to isolate energy sources. Personnel are advised to treat all wires and gas/propane equipment as energized until proven otherwise and to avoid actions that could cause arcing or explosions.

1. Utility Emergencies
2013

2. What types of Utility
Emergencies?
• Electricity
• Natural Gas
• Propane
• Water

3. Electrical Hazards
Distribution System
Primary Lines
Secondary Lines
Transformer Cable TV / Telephone
Lines
Insulators

4. Electrical Hazards
Distribution System
• Primary Lines
• Located at the highest level of the pole
• Carry the greatest amount of power
• Normally bare wire, which gives them
the “look” of support cables

5. Electrical Hazards
Distribution System
• Secondary Lines
• Located one level below the primary
lines, at the second-highest level of
the pole.
• Carry voltages less than primaries.
• May be coated for protection from the
elements. This coating DOES NOT
provide insulation from live current.

6. Electrical Hazards
Distribution System
• Cable TV / Telephone Lines
• Located at the lowest level of the pole
• Carry lower voltages than primaries & secondaries
• Should be coated for protection from the elements. This coating DOES
NOT guaranty insulation from live current.
• Should always be considered dangerous due to back-feeding or cross-
conduction.

7. Electrical Hazards
Downed Wires
Pole / Transformer Fires
Vehicle / Pole Accidents
Wires on Vehicle
Vehicles Contacting Wires
Manhole Fires
Substations

8. Electrical Hazards
Step Potential
The voltage decreases as the distance from
the point of contact increases

9. Electrical Hazards
Types of Emergencies
Downed Wires

10. Electrical Hazards
Types of Emergencies
• Downed Wires
• Always treat all downed wires, including
Cable TV & telephone wires, as energized at
high voltage until proven otherwise.

11. Electrical Hazards
Types of Emergencies
• Downed Lines
• It is impossible to determine if a wire is
energized by its appearance.
• Never attempt to move or cut any downed
conductors. Remember, wooden or
fiberglass pike poles MAY BE conductive.

12. Electrical Hazards
Types of Emergencies
• Downed Wires
• Upon arrival
• Establish a safety zone and secure the area.
• If possible, the safety zone should extend a minimum of two full span
lengths of wire in each direction beyond the downed wire.
• Poles may break and fall due to stress
• Wires can slip through insulators and sag to the ground
• Wire may be contacting metal fences, guard rails, buildings, etc.

13. Electrical Hazards
Types of Emergencies
• Downed Wires
Safety Zone

14. Electrical Hazards
Types of Emergencies
• Downed Wires
• Any high-voltage wire, when disturbed, can
get out of control.
• FF boots do not guarantee insulation from
energized wires.
• NO HIGH VOLTAGE wire is insulated. The
coating sometimes seen is to provide
protection from the elements.

15. Electrical Hazards
Types of Emergencies
• Downed Wires
• Bodies in contact with live wires may be
energized. DO NOT TOUCH the individual
until the wire is tested dead and cleared from
the body.
• Wires should not be assumed dead until
they are tested dead or certain assurance
from the electric company personnel is
received.

16. P
Electrical Hazards
o Types of Emergencies
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17. Electrical Hazards
Types of Emergencies
• Pole / Transformer Fires
• If a downed wire is involved in the fire, use a
fog pattern to keep the fire in check and
protect the surrounding area.
• If the fire is at the top of the pole, or is on
pole-mounted equipment, and it appears that
the fire will not endanger life or property, let it
burn. Remember, once electrical equipment
is involved in fire, it is not salvageable.

18. Electrical Hazards
Types of Emergencies
• Pole / Transformer Fires
• In the rare case where the fire must be attacked and/or the equipment
has not been de-energized, exercise extreme caution.
• Most pole fires are caused by:
• Lightning
• Insulator breakdown (broken or contaminated by salt spray or air
pollution)
• Equipment failure

19. Electrical Hazards
Types of Emergencies
• Pole / Transformer Fires
• As most pole-mounted equipment contains oil, the extinguishing agents
of choice are dry chemical and water fog.
• If the equipment is still energized, little can be done to extinguish the
fire, as the oil will continue to re-ignite.
• When in doubt, secure the area, establish a safety zone and allow
electric company to arrive and determine the safe and proper course of
action.

20. Electrical Hazards
Types of Emergencies
Vehicle
/ Pole
Acciden
ts

21. Electrical Hazards
Types of Emergencies
• Vehicle / Pole Accidents
• All potential hazards should be thoroughly evaluated.
• Approach cautiously - Establish a safety zone.
• If a fire is present, use a fog pattern rather than straight stream.
• Remember: the vehicle and anything attached to it may be energized.
• Approach the vehicle to no closer than 10 feet.

22. Electrical Hazards
Types of Emergencies
• Vehicle / Pole Accidents
• Occupants have one overriding thought . . . . To get out of the vehicle.
• Gain their confidence and order them to remain in the vehicle.
• In dire emergencies and under ideal conditions, the driver can try to
move the vehicle from underneath the wires.
• However, the wire may weld itself to the vehicle – preventing
movement.

23. Electrical Hazards
Types of Emergencies
• Vehicle / Pole Accidents
• If it is absolutely necessary to have the
occupants exit the vehicle, they should be
given explicit instructions and told not to
come in contact with the vehicle and the
ground at the same time.
• Once on the ground, small shuffling steps
should be taken to move away from the
involved vehicle (remember - step potential).

24. Electrical Hazards
Types of Emergencies
Vehicle
/ Pole
Acciden
ts

25. Electrical Hazards
Types of Emergencies
• Vehicle / Pole Accidents
• In some cases, poles struck by a vehicle will
sever, leaving the top portion suspended in air
by the wires.
• In these cases, if energized wires are not
contacting the vehicle, the occupants should be
evacuated and a secure zone established.
• The supported section may fail, causing
energized wires to fall to the ground.

26. Electrical Hazards
Types of Emergencies
• Vehicles contacting wires

27. Electrical Hazards
Types of Emergencies
• Vehicles contacting wires
• Procedures for vehicles in contact with
energized wires are the same as those for
vehicle / pole accidents.
• The “step potential” affects the area around the
involved vehicle, as well.
• Unless threatened by fire or some other
danger, occupants should remain on the
vehicle until the wires can be de-energized.

28. Electrical Hazards
Types of Emergencies
• Vehicles contacting wires
• The entire vehicle may be energized, causing
tires and fluids to burn, lug nuts to weld & other
components to fail, especially pressurized
cylinders (bumpers / hatch lifts).
• Fires should be extinguished with a fog pattern
– NOT a straight stream.

29. Electrical Hazards
Structure Fires
• Meters
• Never pull an electric
meter to de-energize a
bldg.

30. Electrical Hazards
Structure Fires
• It is usually best to leave the power on to structures as long as you
safely can.
• When safe firefighting tactics require the power to be shut off, the
following actions are appropriate:
• De-energize the fire-affected area by removing fuses or opening
circuit breakers.
• Open the main disconnects to de-energize the entire bldg.
• If the bldg. is damaged to the extent that service is no longer req’d
or puts personnel in jeopardy, the service to the bldg. should be
disconnected by the electric company.

31. Electrical Hazards
Structure Fires
• Reasons for NOT removing meters
• Pulling the meter may not de-energize the electric service to the bldg.
• Services over 200 amps are metered by current transformers. Pulling
the meter will not shut off the electric supply.
• People have developed many unique methods to bypass the meter.
• If there is a presence of explosive gases in the bldg., the service wire
piping can act like a chimney. A small amount of gas may be present in
the meter socket and pipe. When the meter is removed, a small arc will
occur and the gas may explode.

32. Electrical Hazards
Structure Fires
• Some meter bases are equipped with automatic
bypasses. When the meter is removed, the
bypasses close and the bldg. remains
energized.
• If the meter is exposed to the heat of the fire, it
can build up internal stresses and explode on
contact.
• After a meter is removed, the energized
contacts in the meter socket are left exposed,
posing a shock hazard to anyone near the
meter base.

33. Properties of Natural Gas
• Odorless – Colorless - Tasteless
• Methyl Mercaptan is added to give it it’s
distinguishable “rotten egg” odor
• Odorized natural gas is detectable at
concentrations significantly less than 1%

34. Properties of Natural Gas
• 94% - methane 4% - ethane
• Often listed as a “Hazardous Material” due to
it’s flammability, not it’s toxicity
• Only through it’s ability to displace oxygen
can it pose an asphyxiation hazard

35. Properties of Natural Gas
• Vapor Density Natural Gas
0.7
30% lighter than air
Air = 1
Will rise and collect near the ceiling
Propane
1. 56

36. Properties of Natural Gas
• Flammable Limits
Too Rich
14%
Flammable Range
4.5%
Too Lean

37. Properties of Natural Gas
• Heating Valve
• 1,000 BTU per cubic foot

38. Properties of Natural Gas
• Combustion Products
• Complete combustion = heat, carbon dioxide
& water vapor
• Incomplete combustion = carbon monoxide

39. Properties of Natural Gas
• Ignition Temperature
Natural Gas - 1163º F
Propane - 957º F
Gasoline - 632º F

40. Natural Gas Equipment
• Piping
• Distribution piping is normally buried
between 12” and 18” below ground level

41. Natural Gas Equipment
• Shut-off Valves
Square - Handle T - Handle
L - Handle
Side View

42. Natural Gas Equipment
• Shut-off Valves
Closed Position
Open Position
Top View

43. Natural Gas Equipment
• Typical Residential Installation

44. Natural Gas Equipment
• Typical Commercial Installation
Meter
Regulator
Valve

45. Natural Gas Emergencies
• Types of Emergencies
Odors / Leaks Ou
tsi
de
Inside Building
Fire Bu
ild
ing

46. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Inside
• Approach incident from upwind, if possible.
• Position apparatus at least 150” from scene.
• Investigate for the source of the odor with the gas detectors.
• Wear SCBA in case less then ideal air conditions are encountered.
• If a strong odor is encountered or leak is confirmed, evacuate the bldg.
of all occupants.

47. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Inside
• Shut off the source of the gas leak. Any thing
disconnected by us of National Fuel cannot
be reconnected by us or National Fuel.
• If source cannot be determined call National
Fuel to find leak.
• Advise occupants that National Fuel has
been called to find leak this is a no charge
feature.

48. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Inside
• Use only intrinsically safe radios / handlights.
O K
• Hand tools should be spark-proof
(1663 / 1665).

49. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Inside
• Gas valves turned OFF by FD personnel
SHOULD NEVER be turned back on without
National Fuel on scene.
• No one should re enter the bldg. until
National Fuel has secured the leak and
determined that it is safe to enter.

50. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Outside
• If unignited gas is escaping from the ground, either from an excavation
site or from an open pipe outside of a bldg., notify National Fuel
immediately.
• Establish a safe area around the incident scene.
• Extinguish all open flames.
• Check surrounding buildings, especially basements, for the presence of
gas.
• Gas can migrate through the ground, following pipes or natural
stratifications in the earth.

51. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Outside
• Restrict or re-route traffic until National Fuel
personnel can bring the gas flow under control.
• Although water fog streams can be used to
disperse escaping vapors, they are usually
ineffective since the lighter-than-air gas
naturally rises.
• If water fog is used, caution must be exercised
to avoid filling excavation sites with water.

52. Natural Gas Emergencies
Emergency Response
Emergency Response
• Odors/Leaks - Outside
• FD personnel should never clamp or crimp a
gas line. Static electricity could ignite
escaping gas, resulting in a sudden and
violent ignition.
• Hand tools should be spark-proof (1663 /
1665).

53. Natural Gas Emergencies
Emergency Response
Emergency Response
• Fires - Inside
• Notify National Fuel immediately upon
receipt of alarm.
• The IC should determine if the gas can safely
be shut off inside the bldg. or at the meter.

54. Natural Gas Emergencies
Emergency Response
Emergency Response
• Fires - Inside
• In certain industrial / commercial settings,
turning off the gas supply can seriously
interrupt important and costly industrial
processes and should only be done upon
evaluation with company personnel and
National Fuel.
• If the gas supply cannot be shut off, the
surrounding combustibles should be kept wet
with a fog stream.

55. Natural Gas Emergencies
Emergency Response
Emergency Response
• Fire - Outside
• Notify National Fuel immediately upon receipt of alarm.
• The best method of controlling outdoor gas fires is to shut off the gas
flow.
• In most cases, FD personnel should not attempt to extinguish the fire
while the gas is still escaping.
• BURNING GAS WILL NOT EXPLODE.
• Secure the area and protect exposures, if necessary.

56. Natural Gas Emergencies
Emergency Response
Emergency Response
• Fire - Outside
• IF it is necessary to extinguish the fire before
the gas flow can be stopped, use a Dry
Chem extinguisher aimed at the base of the
flame and wet the surrounding area with
water fog to prevent the re-ignition of
combustibles.

57. Electrical Hazards
Types of Emergencies
• Manhole Fires

58. Electrical Hazards
Types of Emergencies
• Manhole Fires
• Notify appropriate utility companies immediately upon receipt of the
alarm.
• Secure the area. Establish a safety zone.
• If the cover is in place, do not attempt to remove it without first
consulting with appropriate utility companies personnel.
• If flammable gases are present, removing the cover may provide
sufficient air to cause an explosion.
• If a transformer has failed and the oil is above it’s ignition temperature,
removing the cover may cause a backdraft.

59. Electrical Hazards
Types of Emergencies
• Manhole Fires
• A spark resulting from removing the cover may
cause an explosion of gases in the manhole.
• If there are gases present in the ductwork
running from manhole-to-manhole, subsequent
explosions could occur down the line.
• Explosions have been known to propel a
manhole cover (which weigh approx. 270 lbs.) a
significant distance.

60. Electrical Hazards
Types of Emergencies
• Manhole Fires
• If the manhole cover is already off, do not enter the manhole or take
any further action until the situation has been evaluated by the
appropriate company personnel.
• Manholes must always be treated as highly hazardous confined
spaces.
• Except for rescue, FD personnel should never enter a manhole.

61. Electrical Hazards
Types of Emergencies
• Manhole Fires
• REMEMBER - Unless there is human life at
stake, there is no great urgency to extinguish a
fire or enter the manhole. Maximum damage to
the equipment has already taken place.

62. Electrical Hazards
Summary
Summary
• Treat all wires as dangerous and energized at
high voltage until tested and proven otherwise.
• Exercise extreme caution when approaching
the scene, especially at night.
• Establish a safety zone and prevent all
unauthorized persons from approaching the
scene.

63. Electrical Hazards
Summary
Summary by.
• Secure the scene until relieved
• Never tamper with energized wires or
equipment.
• Your primary responsibility is to save
lives . . . including your own.

64. References
• City of Abbotsford Fire Rescue Service -
powerpoint “Controlling The Utilities”