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“ “ Excellence Through Training ”Excellence Through Training ”
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Firefighter SafetyFirefighter Safety
Controlling the UtilitiesControlling the Utilities
Natural GasNatural Gas ElectricityElectricity
DANGER
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Properties of Natural GasProperties of Natural Gas
1971
1 0
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Properties of Natural GasProperties of Natural Gas
Odorless – Colorless - TastelessOdorless – Colorless - Tasteless
Methyl Mercaptan is added to give it it’s Methyl Mercaptan is added to give it it’s distinguishable “rotten egg” odordistinguishable “rotten egg” odor
Odorized natural gas is detectable at Odorized natural gas is detectable at concentrations significantly less than 1%concentrations significantly less than 1%
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Properties of Natural GasProperties of Natural Gas
Non-ToxicNon-Toxic
94% - methane94% - methane 4% - ethane4% - ethane
Often listed as a “Hazardous Material” due to it’s Often listed as a “Hazardous Material” due to it’s flammability, not it’s toxicityflammability, not it’s toxicity
Only through it’s ability to displace oxygen can it Only through it’s ability to displace oxygen can it pose an asphyxiation hazardpose an asphyxiation hazard
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Properties of Natural GasProperties of Natural Gas
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Properties of Natural GasProperties of Natural Gas
Vapor DensityVapor Density
30% lighter than air30% lighter than air
Will rise and collect near the ceiling
Natural Gas0.7
Air = 1
Propane1. 56
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Properties of Natural GasProperties of Natural Gas
Flammable LimitsFlammable Limits
4.5%
Too Lean
14%
Too Rich
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Properties of Natural GasProperties of Natural Gas
Heating ValueHeating Value
1,000 BTU per cubic foot1,000 BTU per cubic foot
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Properties of Natural GasProperties of Natural Gas
Combustion ProductsCombustion Products
Complete combustion = heat, carbon dioxide & water Complete combustion = heat, carbon dioxide & water vaporvapor
Incomplete combustion = carbon monoxideIncomplete combustion = carbon monoxide
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Properties of Natural GasProperties of Natural Gas
Ignition TemperatureIgnition Temperature
Natural Gas - 1163Natural Gas - 1163º Fº F
Propane - 957Propane - 957º Fº F
Gasoline - 632Gasoline - 632º Fº F
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Properties of Natural GasProperties of Natural Gas
Natural Gas SupplyNatural Gas Supply
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Properties of Natural GasProperties of Natural Gas
Approx. Range of Flammability
(% mix with air)
Vapor Density
(Air = 1.0)
Approximate Ignition
Temperature
Natural Gas 4.5 - 14.0 .70 1163ºF
Hydrogen 4.0 – 7.5 .07 1076ºF
Propane 2.2 – 9.5 1.56 957ºF
Butane 1.9 – 8.5 2.01 912ºF
Gasoline 1.4 – 7.6 3.00 632ºF
ComparisonsComparisons
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Natural Gas EquipmentNatural Gas Equipment
Distribution SystemDistribution System
Type of System Pressure
Transmission Line(High Pressure)
300 – 1000 psig
Distribution Main(High Pressure)
60 – 300 psig
Distribution Main(Modified High Pressure)
5 – 60 psig
Distribution Main(Low Pressure)
¼ psig
Service / Customer Line
¼ psig
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Natural Gas EquipmentNatural Gas Equipment
Distribution SystemDistribution System
Each time the pressure is reduced, over Each time the pressure is reduced, over pressure protection is provided by a relief pressure protection is provided by a relief
valve or automatic shut offvalve or automatic shut off
A relief valve venting gas to the atmosphere is A relief valve venting gas to the atmosphere is performing its proper function and should never be cut performing its proper function and should never be cut
off or restricted until the gas company arrives and makes off or restricted until the gas company arrives and makes corrections to the systemcorrections to the system
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Natural Gas EquipmentNatural Gas Equipment
Material Color Size Pressure
Bare Steel - - - - - - 2” – 6” Up to 60 psi
Wrapped Steel
Yellow / brown ½” – 20”
Up to 1000 psi
Wrought Iron
- - - - - - 2” – 6” Up to 60 psi
Polyethylene Plastic
Black / orange / yellow
½” – 6” Up to 60 psi
Cast Iron - - - - - - 4” – 20” ¼ psi
Copper - - - - - - ¼” - ½” ¼ psi
PipingPiping
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Natural Gas EquipmentNatural Gas Equipment
POLYETHYLENE PIPE
Polyethylene pipe is buried with a 12 gauge Polyethylene pipe is buried with a 12 gauge wire for ease of locating – it has nothing to do wire for ease of locating – it has nothing to do
with grounding or bondingwith grounding or bonding
PipingPiping
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Natural Gas EquipmentNatural Gas Equipment
Distribution piping is normally buried Distribution piping is normally buried between 12” and 18” below ground levelbetween 12” and 18” below ground level
PipingPiping
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Natural Gas EquipmentNatural Gas Equipment
Shut-off ValvesShut-off Valves
Square - HandleSquare - Handle
L - HandleL - Handle
T - HandleT - Handle
Side ViewSide View
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Natural Gas EquipmentNatural Gas Equipment
Shut-off ValvesShut-off Valves
Closed PositionClosed Position
Open PositionOpen Position
Top ViewTop View
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Natural Gas EquipmentNatural Gas Equipment
Typical Residential InstallationTypical Residential Installation
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Natural Gas EquipmentNatural Gas Equipment
Typical Residential InstallationTypical Residential Installation
Regulator
Relief Valve
Valve
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Natural Gas EquipmentNatural Gas Equipment
Typical Residential InstallationTypical Residential Installation
Meter
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Natural Gas EquipmentNatural Gas Equipment
Commercial InstallationCommercial Installation
Meter
Valve
Regulator
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Natural Gas EmergenciesNatural Gas Emergencies
Types of EmergenciesTypes of Emergencies
Odors / LeaksOdors / Leaks
FireFire
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / LeaksInsideInside
1)1) Approach incident from upwind, if possible.Approach incident from upwind, if possible.
2)2) Position apparatus Position apparatus at leastat least 150” from scene. 150” from scene.
3)3) Investigate for the source of the odor with the GasTrac Investigate for the source of the odor with the GasTrac & Mini-Gas.& Mini-Gas.
WCB prohibits entry into a confined space having an atmosphere WCB prohibits entry into a confined space having an atmosphere containing over 10% LEL combustible gascontaining over 10% LEL combustible gas
4)4) If a strong odor is encountered or leak is confirmed, If a strong odor is encountered or leak is confirmed, evacuate the bldg. of all occupants.evacuate the bldg. of all occupants.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / LeaksInsideInside
5)5) Notify BC GAS - Gas Op's to respond.Notify BC GAS - Gas Op's to respond.
6)6) Ventilate the bldg. by opening doors & windows. Ventilate the bldg. by opening doors & windows. Remember to open windows on top.Remember to open windows on top.
7)7) Do not operate electrical switches / telephones.Do not operate electrical switches / telephones.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / Leaks
9)9) If a leak is confirmed, the IC should determine if it can If a leak is confirmed, the IC should determine if it can be stopped or if the gas needs to be shut off at the valve.be stopped or if the gas needs to be shut off at the valve.
OKOK
InsideInside
8)8) Use only intrinsically safe radios / handlights.Use only intrinsically safe radios / handlights.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / Leaks
11)11) Gas valves turned OFF by FD personnel SHOULD Gas valves turned OFF by FD personnel SHOULD NEVER be turned back on without BC GAS - Gas Op's NEVER be turned back on without BC GAS - Gas Op's on scene.on scene.
12) No one should re enter the bldg. until BC GAS - Gas 12) No one should re enter the bldg. until BC GAS - Gas Op's has secured the leak and determined that it is safe Op's has secured the leak and determined that it is safe to enter.to enter.
InsideInside
10) Hand tools should be spark-proof 10) Hand tools should be spark-proof (1663 / 1665).(1663 / 1665).
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / LeaksOutsideOutside
1)1) If unignited gas is escaping from the ground, either If unignited gas is escaping from the ground, either from an excavation site or from an open pipe outside of from an excavation site or from an open pipe outside of a bldg., notify BC GAS - Gas Op's immediately.a bldg., notify BC GAS - Gas Op's immediately.
2)2) Establish a safe area around the incident scene.Establish a safe area around the incident scene.
3)3) Extinguish all open flames.Extinguish all open flames.
4)4) Check surrounding bldgs., especially basements, for the Check surrounding bldgs., especially basements, for the presence of gas.presence of gas.
Gas can migrate through the ground, following pipes or natural Gas can migrate through the ground, following pipes or natural stratifications in the earth.stratifications in the earth.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / LeaksOutsideOutside
5)5) Restrict or re-route traffic until BC GAS - Gas Op's Restrict or re-route traffic until BC GAS - Gas Op's personnel can bring the gas flow under control.personnel can bring the gas flow under control.
6)6) Although water fog streams can be used to disperse Although water fog streams can be used to disperse escaping vapors, they are usually ineffective since the escaping vapors, they are usually ineffective since the lighter-than-air gas naturally rises.lighter-than-air gas naturally rises.
7)7) If water fog is used, caution must be exercised to avoid If water fog is used, caution must be exercised to avoid filling excavation sites with water.filling excavation sites with water.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
Odors / LeaksOdors / LeaksOutsideOutside
8)8) FD personnel should never clamp or crimp a gas line. FD personnel should never clamp or crimp a gas line. Static electricity could ignite escaping gas, resulting in a Static electricity could ignite escaping gas, resulting in a sudden and violent ignition.sudden and violent ignition.
9)9) Hand tools should be spark-proof Hand tools should be spark-proof (1663 / (1663 / 1665).1665).
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
FiresFiresInsideInside
1)1) Notify BC GAS - Gas Op's immediately upon receipt of Notify BC GAS - Gas Op's immediately upon receipt of alarm.alarm.
2)2) The IC should determine if the gas can safely be shut off The IC should determine if the gas can safely be shut off inside the bldg. or at the meter. inside the bldg. or at the meter.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
FiresFiresInsideInside
3) In certain industrial / commercial settings, turning off the 3) In certain industrial / commercial settings, turning off the gas supply can seriously interrupt important and costly gas supply can seriously interrupt important and costly industrial processes and should only be done upon industrial processes and should only be done upon evaluation with company personnel and BC GAS - Gas evaluation with company personnel and BC GAS - Gas Op's.Op's.
4) If the gas supply cannot be shut off, the surrounding 4) If the gas supply cannot be shut off, the surrounding combustibles should be kept wet with a fog stream.combustibles should be kept wet with a fog stream.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
FiresFiresOutsideOutside
1)1) Notify BC GAS - Gas Op's immediately upon receipt of Notify BC GAS - Gas Op's immediately upon receipt of alarm.alarm.
2)2) The best method of controlling outdoor gas fires is to The best method of controlling outdoor gas fires is to shut off the gas flow.shut off the gas flow.
3)3) In most cases, FD personnel should not attempt to In most cases, FD personnel should not attempt to extinguish the fire while the gas is still escaping.extinguish the fire while the gas is still escaping.
4)4) BURNING GAS WILL NOT EXPLODE.BURNING GAS WILL NOT EXPLODE.
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Natural Gas EmergenciesNatural Gas EmergenciesEmergency ResponseEmergency Response
FiresFiresOutsideOutside
5) Secure the area and protect exposures, if necessary.5) Secure the area and protect exposures, if necessary.
6)6) IF it is necessary to extinguish the fire before the gas IF it is necessary to extinguish the fire before the gas flow can be stopped, use a Dry Chem extinguisher flow can be stopped, use a Dry Chem extinguisher aimed at the base of the flame and wet the surrounding aimed at the base of the flame and wet the surrounding area with water fog to prevent the re-ignition of area with water fog to prevent the re-ignition of combustibles.combustibles.
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Electrical EmergenciesElectrical Emergencies
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Electrical HazardsElectrical Hazards
Distribution SystemDistribution System
TransformerTransformer
Primary LinesPrimary Lines
Secondary LinesSecondary Lines
Cable TV / Cable TV / Telephone LinesTelephone Lines InsulatorsInsulators
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Electrical HazardsElectrical Hazards
Distribution SystemDistribution System
Primary LinesPrimary Lines- located at the highest level of the polelocated at the highest level of the pole
- carry the greatest amount of powercarry the greatest amount of power
- normally bare wire, which gives them normally bare wire, which gives them the “look” of support cablesthe “look” of support cables
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Electrical HazardsElectrical Hazards
Distribution SystemDistribution System
Secondary LinesSecondary Lines- located one level below the primary located one level below the primary lines, at the second-highest level of the lines, at the second-highest level of the pole.pole.
- carry voltages less than primaries.carry voltages less than primaries.
- may be coated for protection from the may be coated for protection from the elements. This coating DOES NOT elements. This coating DOES NOT provide insulation from live current.provide insulation from live current.
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Electrical HazardsElectrical Hazards
Distribution SystemDistribution System
Cable TV / Telephone LinesCable TV / Telephone Lines- located at the lowest level of the polelocated at the lowest level of the pole
- carry lower voltages than primaries & secondariescarry lower voltages than primaries & secondaries
- should be coated for protection from the elements. This should be coated for protection from the elements. This coating DOES NOT guaranty insulation from live current.coating DOES NOT guaranty insulation from live current.
- should always be considered dangerous due to back-should always be considered dangerous due to back-feeding or cross-conduction.feeding or cross-conduction.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
Pole / Transformer FiresPole / Transformer Fires
Vehicle / Pole AccidentsVehicle / Pole Accidents
Wires on VehicleWires on Vehicle
Vehicles Contacting WiresVehicles Contacting Wires
Manhole FiresManhole Fires
SubstationsSubstationsCAUTION CAUTION CAUTION CAUTION
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Electrical HazardsElectrical HazardsStep PotentialStep Potential
The voltage decreases as the distance The voltage decreases as the distance from the point of contact increasesfrom the point of contact increases
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
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Electrical HazardsElectrical HazardsTypes of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
Always treat all downed wires, including Cable TV & Always treat all downed wires, including Cable TV & telephone wires, as energized at high voltage until proven telephone wires, as energized at high voltage until proven
otherwise.otherwise.
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Electrical HazardsElectrical HazardsTypes of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
• It is impossible to determine if a wire is energized by its It is impossible to determine if a wire is energized by its appearance.appearance.
• Never attempt to move or cut any downed conductors. Never attempt to move or cut any downed conductors. Remember, wooden or fiberglass pike poles MAY BE Remember, wooden or fiberglass pike poles MAY BE conductive.conductive.
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Electrical HazardsElectrical HazardsTypes of EmergenciesTypes of Emergencies
Downed WiresDowned WiresUpon arrivalUpon arrival
• Establish a safety zone and secure the area.Establish a safety zone and secure the area.
• If possible, the safety zone should extend a minimum of If possible, the safety zone should extend a minimum of two full span lengths of wire in each direction beyond the two full span lengths of wire in each direction beyond the downed wire.downed wire.
- poles may break and fall due to stresspoles may break and fall due to stress
- wires can slip through insulators and sag to the groundwires can slip through insulators and sag to the ground
- wire may be contacting metal fences, guard rails, wire may be contacting metal fences, guard rails, buildings, etc.buildings, etc.
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Electrical HazardsElectrical HazardsTypes of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
Safety ZoneSafety Zone
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Electrical HazardsElectrical HazardsTypes of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
• Any high-voltage wire, when disturbed, can get out Any high-voltage wire, when disturbed, can get out of control.of control.
• FF boots do not guaranty insulation from energized FF boots do not guaranty insulation from energized wires.wires.
• NO HIGH VOLTAGE wire is insulated. The NO HIGH VOLTAGE wire is insulated. The coating sometimes seen is to provide protection from coating sometimes seen is to provide protection from the elements.the elements.
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Electrical HazardsElectrical HazardsTypes of EmergenciesTypes of Emergencies
Downed WiresDowned Wires
• Bodies in contact with live wires may be energized. Bodies in contact with live wires may be energized. DO NOT TOUCH the individual until the wire is DO NOT TOUCH the individual until the wire is tested dead and cleared form the body.tested dead and cleared form the body.
• Wires should not be assumed dead until they are Wires should not be assumed dead until they are tested dead or certain assurance from BC HYDRO tested dead or certain assurance from BC HYDRO personnel is rec’d.personnel is rec’d.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Pole / Transformer FiresPole / Transformer Fires
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Pole / Transformer FiresPole / Transformer Fires
• If a downed wire is involved in the fire, use a fog If a downed wire is involved in the fire, use a fog pattern to keep the fire in check and protect the pattern to keep the fire in check and protect the surrounding area.surrounding area.
• If the fire is at the top of the pole, or is on pole-mounted 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 equipment, and it appears that the fire will not endanger life or property, let it burn. Remember, once electrical life or property, let it burn. Remember, once electrical equipment is involved in fire, it is not salvageable.equipment is involved in fire, it is not salvageable.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Pole / Transformer FiresPole / Transformer Fires
• In the rare case where the fire must be attacked and/or In the rare case where the fire must be attacked and/or the equipment has not been de-energized, exercise the equipment has not been de-energized, exercise extreme caution.extreme caution.
• Most pole fires are caused by:Most pole fires are caused by:
– lightninglightning
– insulator breakdown (broken or contaminated by insulator breakdown (broken or contaminated by salt spray or air pollution)salt spray or air pollution)
– equipment failureequipment failure
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Pole / Transformer FiresPole / Transformer Fires
• As most pole-mounted equipment contains oil, the As most pole-mounted equipment contains oil, the extinguishing agents of choice are dry chemical and extinguishing agents of choice are dry chemical and water fog.water fog.
• If the equipment is still energized, little can be done to If the equipment is still energized, little can be done to extinguish the fire, as the oil will continue to re-ignite.extinguish the fire, as the oil will continue to re-ignite.
• When in doubt, secure the area, establish a safety zone When in doubt, secure the area, establish a safety zone and allow BC HYDRO to arrive and determine the safe and allow BC HYDRO to arrive and determine the safe and proper course of action.and proper course of action.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicle / Pole AccidentsVehicle / Pole Accidents
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
• All potential hazards should be thoroughly evaluated.All potential hazards should be thoroughly evaluated.
• Approach cautiously - Establish a safety zone.Approach cautiously - Establish a safety zone.
• If a fire is present, use a fog pattern rather than straight If a fire is present, use a fog pattern rather than straight stream.stream.
•Remember: the vehicle Remember: the vehicle and anything attached to itand anything attached to it may be may be energized.energized.
•Approach the vehicle to no closer than 10 feet.Approach the vehicle to no closer than 10 feet.
Vehicle / Pole AccidentsVehicle / Pole Accidents
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
•Occupants have one overriding thought . . . . To get out of Occupants have one overriding thought . . . . To get out of the vehicle.the vehicle.
• Gain their confidence and order them to remain in the Gain their confidence and order them to remain in the vehicle.vehicle.
• In dire emergencies and under ideal conditions, the driver In dire emergencies and under ideal conditions, the driver can try to move the vehicle from underneath the wires.can try to move the vehicle from underneath the wires.
• However, the wire may weld itself to the vehicle – However, the wire may weld itself to the vehicle – preventing movement.preventing movement.
Vehicle / Pole AccidentsVehicle / Pole Accidents
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicle / Pole AccidentsVehicle / Pole Accidents
• If it is absolutely necessary to have the occupants exit the If it is absolutely necessary to have the occupants exit the vehicle, they should be given explicit instructions and told not vehicle, they should be given explicit instructions and told not to come in contact with the vehicle and the ground at the same to come in contact with the vehicle and the ground at the same time.time.
• Once on the ground, small shuffling steps should be taken to Once on the ground, small shuffling steps should be taken to move away from the involved vehicle (remember - step move away from the involved vehicle (remember - step potential).potential).
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicle / Pole AccidentsVehicle / Pole Accidents
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicle / Pole AccidentsVehicle / Pole Accidents
In some cases, poles struck by a vehicle will sever, leaving In some cases, poles struck by a vehicle will sever, leaving the top portion suspended in air by the wires.the top portion suspended in air by the wires.
In these cases, if energized wires are not contacting the In these cases, if energized wires are not contacting the vehicle, the occupants should be evacuated and a secure zone vehicle, the occupants should be evacuated and a secure zone
established.established.
The supported section may fail, causing energized wires to The supported section may fail, causing energized wires to fall to the ground.fall to the ground.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicles contacting wiresVehicles contacting wires
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicles contacting wiresVehicles contacting wires
Procedures for vehicles in contact with energized wires are the Procedures for vehicles in contact with energized wires are the same as those for vehicle / pole accidents.same as those for vehicle / pole accidents.
The “step potential” affects the area around the involved The “step potential” affects the area around the involved vehicle, as well.vehicle, as well.
Unless threatened by fire or some other danger, occupants Unless threatened by fire or some other danger, occupants should remain on the vehicle until the wires can be de-should remain on the vehicle until the wires can be de-
energized.energized.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Vehicles contacting wiresVehicles contacting wires
The entire vehicle may be energized, causing tires and fluids to The entire vehicle may be energized, causing tires and fluids to burn, lug nuts to weld & other components to fail, especially burn, lug nuts to weld & other components to fail, especially
pressurized cylinders (bumpers / hatch lifts).pressurized cylinders (bumpers / hatch lifts).
Fires should be extinguished with a fog pattern – NOT a Fires should be extinguished with a fog pattern – NOT a straight stream.straight stream.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Manhole FiresManhole Fires
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Manhole FiresManhole Fires• Notify BC HYDRO and BC GAS immediately upon Notify BC HYDRO and BC GAS immediately upon receipt of the alarm.receipt of the alarm.
• Secure the area. Establish a safety zone.Secure the area. Establish a safety zone.
• If the cover is in place, do not attempt to remove it If the cover is in place, do not attempt to remove it without first consulting with BC HYDRO and BC GAS without first consulting with BC HYDRO and BC GAS personnel.personnel.
– If flammable gases are present, removing the cover If flammable gases are present, removing the cover may provide sufficient air to cause an explosion.may provide sufficient air to cause an explosion.
– If a transformer has failed and the oil is above it’s If a transformer has failed and the oil is above it’s ignition temperature, removing the cover may cause a ignition temperature, removing the cover may cause a backdraft.backdraft.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Manhole FiresManhole Fires• A spark resulting from removing the cover may cause A spark resulting from removing the cover may cause an explosion of gases in the manhole.an explosion of gases in the manhole.
• If there are gases present in the ductwork running If there are gases present in the ductwork running from manhole-to-manhole, subsequent explosions could from manhole-to-manhole, subsequent explosions could occur down the line.occur down the line.
• Explosions have been known to propel a manhole cover Explosions have been known to propel a manhole cover (which weigh approx. 270 lbs.) a significant distance.(which weigh approx. 270 lbs.) a significant distance.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Manhole FiresManhole Fires
• If the manhole cover is already off, If the manhole cover is already off, do not enter the do not enter the manholemanhole or take any further action until the situation has or take any further action until the situation has been evaluated by BC HYDRO and BC GAS personnel.been evaluated by BC HYDRO and BC GAS personnel.
• Manholes must always be treated as highly hazardous Manholes must always be treated as highly hazardous confined spaces.confined spaces.
• Except for rescue, FD personnel should never enter a Except for rescue, FD personnel should never enter a manhole.manhole.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
Manhole FiresManhole Fires
REMEMBERREMEMBER
Unless there is Unless there is human life at stake, human life at stake,
there is no great there is no great urgency to extinguish urgency to extinguish
a fire or enter the a fire or enter the manhole. Maximum manhole. Maximum
damage to the damage to the equipment has equipment has
already taken place.already taken place.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
SubstationsSubstations
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
SubstationsSubstations HazardsHazards
• High voltage (overhead & underground)High voltage (overhead & underground)• Open high-voltage workOpen high-voltage work
• Oil-filled switch gear, transformers, etc.Oil-filled switch gear, transformers, etc.• Toxic smoke & gases due to burning oil & insulating Toxic smoke & gases due to burning oil & insulating
materialsmaterials• Intense heat of a fire can collapse steel frameworkIntense heat of a fire can collapse steel framework
• Explosion from oil-filled equipmentExplosion from oil-filled equipment• Exploding glass & porcelain insulatorsExploding glass & porcelain insulators
• Falling wiresFalling wires
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
SubstationsSubstations
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
SubstationsSubstations
• FD personnel should not enter substations, either FD personnel should not enter substations, either private or BC HYDRO, unless accompanied by BC private or BC HYDRO, unless accompanied by BC HYDRO.HYDRO.
• Any electrical apparatus, transformer or switch that Any electrical apparatus, transformer or switch that has been on fire cannot be salvaged.has been on fire cannot be salvaged.
• Efforts should be directed at protecting surrounding Efforts should be directed at protecting surrounding property and awaiting arrival of BC HYDRO.property and awaiting arrival of BC HYDRO.
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Electrical HazardsElectrical Hazards
Types of EmergenciesTypes of Emergencies
SubstationsSubstations
• Some equipment, such as circuit switches and breakers, Some equipment, such as circuit switches and breakers, have porcelain housings that are pressurized with SF-6 have porcelain housings that are pressurized with SF-6 gas. If they are involved in fire and sprayed with water, gas. If they are involved in fire and sprayed with water, the sudden temperature change may cause a violent the sudden temperature change may cause a violent failure.failure.
• Never operate electric utility high-voltage switches that Never operate electric utility high-voltage switches that are within a substation property, mounted on poles, or are within a substation property, mounted on poles, or located within manholes or vaults. Many of these are not located within manholes or vaults. Many of these are not designed to drop electric load.designed to drop electric load.
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Electrical HazardsElectrical Hazards
Structure FiresStructure Fires
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Electrical HazardsElectrical Hazards
Structure FiresStructure FiresIt is usually best to leave the power on to structures as It is usually best to leave the power on to structures as
long as you safely canlong as you safely can
When safe firefighting tactics require the power to be shut When safe firefighting tactics require the power to be shut off, the following actions are appropriate:off, the following actions are appropriate:
de-energize the fire-affected area by removing fuses or opening de-energize the fire-affected area by removing fuses or opening circuit breakers.circuit breakers.
open the main disconnects to de-energize the entire bldg.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 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 or puts personnel in jeopardy, the service to the bldg. should be
disconnected by BC HYDROdisconnected by BC HYDRO
76
Electrical HazardsElectrical Hazards
MetersMeters
BC HYDRO says . . .BC HYDRO says . . .
NeverNever pull an electric pull an electric meter to de-energize a meter to de-energize a
bldg.bldg.
Structure FiresStructure Fires
77
Electrical HazardsElectrical Hazards
MetersMetersReasons for NOT removing metersReasons for NOT removing meters
1)1) Pulling the meter may not de-energize the electric service to the Pulling the meter may not de-energize the electric service to the bldg.bldg.
~ Services over 200 amps are metered by current transformers. Services over 200 amps are metered by current transformers. Pulling the meter Pulling the meter will not will not shut off the electric supply.shut off the electric supply.
~ Some meter bases are equipped with automatic bypasses. When Some meter bases are equipped with automatic bypasses. When the meter is removed, the bypasses close and the bldg. remains the meter is removed, the bypasses close and the bldg. remains energized.energized.
~ People have developed many unique methods to bypass the People have developed many unique methods to bypass the meter.meter.
Structure FiresStructure Fires
78
Electrical HazardsElectrical Hazards
MetersMetersReasons for NOT removing metersReasons for NOT removing meters
2)2) If there is a presence of explosive gases in the bldg., the service wire 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 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 present in the meter socket and pipe. When the meter is removed, a small arc will occur and the gas may explode.small arc will occur and the gas may explode.
3)3) If the meter is exposed to the heat of the fire, it can build up internal If the meter is exposed to the heat of the fire, it can build up internal stresses and explode on contact.stresses and explode on contact.
4)4) After a meter is removed, the energized contacts in the meter socket After a meter is removed, the energized contacts in the meter socket are left exposed, posing a shock hazard to anyone near the meter are left exposed, posing a shock hazard to anyone near the meter base.base.
Structure FiresStructure Fires
79
Electrical HazardsElectrical Hazards
SummarySummary
Treat all wires as dangerous and energized at high voltage Treat all wires as dangerous and energized at high voltage until tested and proven otherwise.until tested and proven otherwise.
Exercise extreme caution when approaching the scene, Exercise extreme caution when approaching the scene, especially at night.especially at night.
Establish a safety zone and prevent all unauthorized Establish a safety zone and prevent all unauthorized persons from approaching the scene.persons from approaching the scene.
Secure the scene until relieved by BC HYDRO.Secure the scene until relieved by BC HYDRO.
Never tamper with energized wires or equipmentNever tamper with energized wires or equipment..
80
Electrical HazardsElectrical Hazards
SummarySummary
Your primary responsibility is to save lives . . . Your primary responsibility is to save lives . . . including your own. including your own.
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