Utility emerg2013

Utility Emergencies2013

What types of Utility Emergencies?

• Electricity

• Natural Gas

• Propane

• Water

Electrical HazardsDistribution SystemDistribution System

TransformerTransformer

Primary LinesPrimary Lines

Secondary LinesSecondary Lines

Cable TV / Telephone Cable TV / Telephone LinesLines

InsulatorsInsulators

Electrical Hazards• 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

Distribution SystemDistribution System

Electrical Hazards• 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.


Electrical Hazards

• 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.


Electrical HazardsDowned Wires

Pole / Transformer Fires

Vehicle / Pole Accidents

Wires on Vehicle

Vehicles Contacting Wires

Manhole Fires

Substations

Electrical HazardsStep PotentialStep Potential

The voltage decreases as the distance from The voltage decreases as the distance from the point of contact increasesthe point of contact increases

Electrical HazardsTypes of EmergenciesTypes of Emergencies

Downed WiresDowned Wires

Electrical Hazards

• Downed Wires

• Always treat all downed wires, including Cable TV & telephone wires, as energized at high voltage until proven otherwise.

Types of EmergenciesTypes of Emergencies

Electrical Hazards

• 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.


Electrical Hazards

• 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.


Electrical Hazards

• Downed WiresTypes of EmergenciesTypes of Emergencies

Safety ZoneSafety Zone

Electrical Hazards

• 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.


Electrical Hazards

• 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.



PPoollee / / TTrraannssffoorrmmeer r FFiirreess

Electrical Hazards

• 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.


Electrical Hazards


• 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


Electrical Hazards


• 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.



Vehicle Vehicle / Pole / Pole

AccidenAccidentsts

Electrical Hazards

• 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.


Electrical Hazards


• 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.


Electrical Hazards


• 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).



Vehicle Vehicle / Pole / Pole

AccidenAccidentsts

Electrical Hazards


• 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.


Electrical Hazards

• Vehicles contacting wiresTypes of EmergenciesTypes of Emergencies

Electrical Hazards

• 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.


Electrical Hazards

• 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.


Electrical Hazards• Meters

• Never pull an electric meter to de-energize a bldg.

Structure Fires

Electrical Hazards• 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.

Structure Fires

Electrical Hazards

• 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.

Structure Fires

Electrical Hazards• 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.

Structure FiresStructure Fires

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%


• 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


• Vapor Density

30% lighter than air30% lighter than air

Will rise and collect near the ceiling

Natural Gas0.7

Air = 1

Propane1. 56


• Flammable Limits

Flammable Range

4.5%

Too Lean

14%

Too Rich


• Heating Valve

• 1,000 BTU per cubic foot


• Combustion Products

• Complete combustion = heat, carbon dioxide & water vapor

• Incomplete combustion = carbon monoxide


• Ignition Temperature

Natural Gas - 1163º FNatural Gas - 1163º F

Propane - 957º FPropane - 957º F

Gasoline - 632º FGasoline - 632º F

Natural Gas Equipment

• Piping

• Distribution piping is normally buried between 12” and 18” below ground level


• Shut-off Valves

Square - HandleSquare - Handle

L - HandleL - Handle

T - HandleT - Handle

Side ViewSide View


• Shut-off Valves

Closed PositionClosed Position

Open PositionOpen Position

Top ViewTop View


• Typical Residential Installation


• Typical Commercial Installation

Meter

Valve

Regulator

Natural Gas Emergencies

• Types of Emergencies

Odors / LeaksOdors / Leaks

FireFireInside Building

Outside Building

Natural Gas EmergenciesEmergency ResponseEmergency 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.



• 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.



• Use only intrinsically safe radios / handlights.

• Hand tools should be spark-proof (1663 / 1665).

OKOK



• 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.


• 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.



• 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.



• 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).


• 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.


• 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.


• 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.


• 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.

Electrical Hazards

• Manhole Fires


Electrical Hazards• 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.


Electrical Hazards

• 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.


Electrical Hazards

• 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.


Electrical Hazards

• 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.


Electrical HazardsSummarySummary

• 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.

Electrical HazardsSummarySummary• Secure the scene until relieved by.

• Never tamper with energized wires or equipment.

• Your primary responsibility is to save lives . . . including your own.

References

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

Utility emerg2013

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