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1 “ Excellence Through Training ”. 2 Firefighter Safety Controlling the Utilities Natural Gas Electricity DANGER.

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Presentation on theme: "1 “ Excellence Through Training ”. 2 Firefighter Safety Controlling the Utilities Natural Gas Electricity DANGER."— Presentation transcript:

1 1 “ Excellence Through Training ”

2 2 Firefighter Safety Controlling the Utilities Natural Gas Electricity DANGER

3 3 Properties of Natural Gas

4 4 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%

5 5 Properties of Natural Gas Non-Toxic 94% - methane4% - 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

6 6 Properties of Natural Gas

7 7 Vapor Density 30% lighter than air Will rise and collect near the ceiling Natural Gas 0.7 Air = 1 Propane 1. 56

8 8 Properties of Natural Gas Flammable Limits 4.5% Too Lean 14% Too Rich

9 9 Properties of Natural Gas Heating Value 1,000 BTU per cubic foot

10 10 Properties of Natural Gas Combustion Products Complete combustion = heat, carbon dioxide & water vapor Incomplete combustion = carbon monoxide

11 11 Properties of Natural Gas Ignition Temperature Natural Gas º F Propane - 957º F Gasoline - 632º F

12 12 Properties of Natural Gas Natural Gas Supply

13 13 Properties of Natural Gas Approx. Range of Flammability (% mix with air) Vapor Density (Air = 1.0) Approximate Ignition Temperature Natural Gas ºF Hydrogen4.0 – ºF Propane2.2 – ºF Butane1.9 – ºF Gasoline1.4 – ºF Comparisons

14 14 Natural Gas Equipment Distribution System Type of SystemPressure 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

15 15 Natural Gas Equipment Distribution System Each time the pressure is reduced, over pressure protection is provided by a relief valve or automatic shut off A relief valve venting gas to the atmosphere is performing its proper function and should never be cut off or restricted until the gas company arrives and makes corrections to the system

16 16 Natural Gas Equipment MaterialColorSizePressure Bare Steel ” – 6”Up to 60 psi Wrapped Steel Yellow / brown ½ ” – 20” Up to 1000 psi Wrought Iron ” – 6”Up to 60 psi Polyethylene Plastic Black / orange / yellow ½ ” – 6” Up to 60 psi Cast Iron ” – 20” ¼ psi Copper- - - ¼ ” - ½ ” ¼ psi Piping

17 17 Natural Gas Equipment POLYETHYLENE PIPE Polyethylene pipe is buried with a 12 gauge wire for ease of locating – it has nothing to do with grounding or bonding Piping

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

19 19 Natural Gas Equipment Shut-off Valves Square - Handle L - Handle T - Handle Side View

20 20 Natural Gas Equipment Shut-off Valves Closed Position Open Position Top View

21 21 Natural Gas Equipment Typical Residential Installation

22 22 Natural Gas Equipment Typical Residential Installation Regulator Relief Valve Valve

23 23 Natural Gas Equipment Typical Residential Installation Meter

24 24 Natural Gas Equipment Commercial Installation Meter Valve Regulator

25 25 Natural Gas Emergencies Types of Emergencies Odors / Leaks Fire

26 26 Natural Gas Emergencies Emergency Response Odors / Leaks Inside 1)Approach incident from upwind, if possible. 2)Position apparatus at least 150” from scene. 3)Investigate for the source of the odor with the GasTrac & Mini-Gas. WCB prohibits entry into a confined space having an atmosphere containing over 10% LEL combustible gas 4)If a strong odor is encountered or leak is confirmed, evacuate the bldg. of all occupants.

27 27 Natural Gas Emergencies Emergency Response Odors / Leaks Inside 5)Notify BC GAS - Gas Op's to respond. 6)Ventilate the bldg. by opening doors & windows. Remember to open windows on top. 7)Do not operate electrical switches / telephones.

28 28 Natural Gas Emergencies Emergency Response Odors / Leaks 9)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. OK Inside 8)Use only intrinsically safe radios / handlights.

29 29 Natural Gas Emergencies Emergency Response Odors / Leaks 11) Gas valves turned OFF by FD personnel SHOULD NEVER be turned back on without BC GAS - Gas Op's on scene. 12) No one should re enter the bldg. until BC GAS - Gas Op's has secured the leak and determined that it is safe to enter. Inside 10) Hand tools should be spark-proof (1663 / 1665).

30 30 Natural Gas Emergencies Emergency Response Odors / Leaks Outside 1)If unignited gas is escaping from the ground, either from an excavation site or from an open pipe outside of a bldg., notify BC GAS - Gas Op's immediately. 2)Establish a safe area around the incident scene. 3)Extinguish all open flames. 4)Check surrounding bldgs., especially basements, for the presence of gas. Gas can migrate through the ground, following pipes or natural stratifications in the earth.

31 31 Natural Gas Emergencies Emergency Response Odors / Leaks Outside 5)Restrict or re-route traffic until BC GAS - Gas Op's personnel can bring the gas flow under control. 6)Although water fog streams can be used to disperse escaping vapors, they are usually ineffective since the lighter-than-air gas naturally rises. 7)If water fog is used, caution must be exercised to avoid filling excavation sites with water.

32 32 Natural Gas Emergencies Emergency Response Odors / Leaks Outside 8)FD personnel should never clamp or crimp a gas line. Static electricity could ignite escaping gas, resulting in a sudden and violent ignition. 9)Hand tools should be spark-proof (1663 / 1665).

33 33 Natural Gas Emergencies Emergency Response Fires Inside 1)Notify BC GAS - Gas Op's immediately upon receipt of alarm. 2)The IC should determine if the gas can safely be shut off inside the bldg. or at the meter.

34 34 Natural Gas Emergencies Emergency Response Fires Inside 3) 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 BC GAS - Gas Op's. 4) If the gas supply cannot be shut off, the surrounding combustibles should be kept wet with a fog stream.

35 35 Natural Gas Emergencies Emergency Response Fires Outside 1)Notify BC GAS - Gas Op's immediately upon receipt of alarm. 2)The best method of controlling outdoor gas fires is to shut off the gas flow. 3)In most cases, FD personnel should not attempt to extinguish the fire while the gas is still escaping. 4)BURNING GAS WILL NOT EXPLODE.

36 36 Natural Gas Emergencies Emergency Response Fires Outside 5) Secure the area and protect exposures, if necessary. 6)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.

37 37 Electrical Emergencies

38 38 Electrical Hazards Distribution System Transformer Primary Lines Secondary Lines Cable TV / Telephone Lines Insulators

39 39 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

40 40 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.

41 41 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.

42 42 Electrical Hazards Types of Emergencies Downed Wires Pole / Transformer Fires Vehicle / Pole Accidents Wires on Vehicle Vehicles Contacting Wires Manhole Fires Substations CAUTIONCAUTIONCAUTIONCAUTION

43 43 Electrical Hazards Step Potential The voltage decreases as the distance from the point of contact increases

44 44 Electrical Hazards Types of Emergencies Downed Wires

45 45 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. Always treat all downed wires, including Cable TV & telephone wires, as energized at high voltage until proven otherwise.

46 46 Electrical Hazards Types of Emergencies Downed Wires It is impossible to determine if a wire is energized by its appearance. 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. Never attempt to move or cut any downed conductors. Remember, wooden or fiberglass pike poles MAY BE conductive.

47 47 Electrical Hazards Types of Emergencies Downed Wires Upon 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 two full span lengths of wire in each direction beyond the downed wire. 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.

48 48 Electrical Hazards Types of Emergencies Downed Wires Safety Zone

49 49 Electrical Hazards Types of Emergencies Downed Wires Any high-voltage wire, when disturbed, can get out of control. Any high-voltage wire, when disturbed, can get out of control. FF boots do not guaranty insulation from energized wires. FF boots do not guaranty insulation from energized wires. NO HIGH VOLTAGE wire is insulated. The coating sometimes seen is to provide protection from the elements. NO HIGH VOLTAGE wire is insulated. The coating sometimes seen is to provide protection from the elements.

50 50 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 form the body. Bodies in contact with live wires may be energized. DO NOT TOUCH the individual until the wire is tested dead and cleared form the body. Wires should not be assumed dead until they are tested dead or certain assurance from BC HYDRO personnel is rec’d. Wires should not be assumed dead until they are tested dead or certain assurance from BC HYDRO personnel is rec’d.

51 51 Electrical Hazards Types of Emergencies Pole / Transformer Fires

52 52 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 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. 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.

53 53 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. 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: Most pole fires are caused by: – lightning – insulator breakdown (broken or contaminated by salt spray or air pollution) – equipment failure

54 54 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. 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. 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 BC HYDRO to arrive and determine the safe and proper course of action. When in doubt, secure the area, establish a safety zone and allow BC HYDRO to arrive and determine the safe and proper course of action.

55 55 Electrical Hazards Types of Emergencies Vehicle / Pole Accidents

56 56 Electrical Hazards Types 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 stream. If a fire is present, use a fog pattern rather than straight stream. Remember: the vehicle and anything attached to it may be energized.Remember: the vehicle and anything attached to it may be energized. Approach the vehicle to no closer than 10 feet.Approach the vehicle to no closer than 10 feet. Vehicle / Pole Accidents

57 57 Electrical Hazards Types of Emergencies Occupants have one overriding thought.... To get out of the vehicle.Occupants have one overriding thought.... To get out of the vehicle. Gain their confidence and order them to remain in 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. 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. However, the wire may weld itself to the vehicle – preventing movement. Vehicle / Pole Accidents

58 58 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. 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). Once on the ground, small shuffling steps should be taken to move away from the involved vehicle (remember - step potential).

59 59 Electrical Hazards Types of Emergencies Vehicle / Pole Accidents

60 60 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 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.

61 61 Electrical Hazards Types of Emergencies Vehicles contacting wires

62 62 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.

63 63 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.

64 64 Electrical Hazards Types of Emergencies Manhole Fires

65 65 Electrical Hazards Types of Emergencies Manhole Fires Notify BC HYDRO and BC GAS immediately upon receipt of the alarm. Notify BC HYDRO and BC GAS immediately upon 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 without first consulting with BC HYDRO and BC GAS personnel. If the cover is in place, do not attempt to remove it without first consulting with BC HYDRO and BC GAS 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.

66 66 Electrical Hazards Types of Emergencies Manhole Fires A spark resulting from removing the cover may cause an explosion of gases in the manhole. 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. 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. Explosions have been known to propel a manhole cover (which weigh approx. 270 lbs.) a significant distance.

67 67 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 BC HYDRO and BC GAS personnel. If the manhole cover is already off, do not enter the manhole or take any further action until the situation has been evaluated by BC HYDRO and BC GAS personnel. Manholes must always be treated as highly hazardous confined spaces. Manholes must always be treated as highly hazardous confined spaces. Except for rescue, FD personnel should never enter a manhole. Except for rescue, FD personnel should never enter a manhole.

68 68 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.

69 69 Electrical Hazards Types of Emergencies Substations

70 70 Electrical Hazards Types of Emergencies Substations Hazards High voltage (overhead & underground) High voltage (overhead & underground) Open high-voltage work Open high-voltage work Oil-filled switch gear, transformers, etc. Oil-filled switch gear, transformers, etc. Toxic smoke & gases due to burning oil & insulating materials Toxic smoke & gases due to burning oil & insulating materials Intense heat of a fire can collapse steel framework Intense heat of a fire can collapse steel framework Explosion from oil-filled equipment Explosion from oil-filled equipment Exploding glass & porcelain insulators Exploding glass & porcelain insulators Falling wires Falling wires

71 71 Electrical Hazards Types of Emergencies Substations

72 72 Electrical Hazards Types of Emergencies Substations FD personnel should not enter substations, either private or BC HYDRO, unless accompanied by BC HYDRO. Any electrical apparatus, transformer or switch that has been on fire cannot be salvaged. Any electrical apparatus, transformer or switch that has been on fire cannot be salvaged. Efforts should be directed at protecting surrounding property and awaiting arrival of BC HYDRO. Efforts should be directed at protecting surrounding property and awaiting arrival of BC HYDRO.

73 73 Electrical Hazards Types of Emergencies Substations Some equipment, such as circuit switches and breakers, have porcelain housings that are pressurized with SF-6 gas. If they are involved in fire and sprayed with water, the sudden temperature change may cause a violent failure. Never operate electric utility high-voltage switches that are within a substation property, mounted on poles, or located within manholes or vaults. Many of these are not designed to drop electric load. Never operate electric utility high-voltage switches that are within a substation property, mounted on poles, or located within manholes or vaults. Many of these are not designed to drop electric load.

74 74 Electrical Hazards Structure Fires

75 75 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 BC HYDRO

76 76 Electrical Hazards Meters BC HYDRO says... Never pull an electric meter to de-energize a bldg. Structure Fires

77 77 Electrical Hazards Meters Reasons for NOT removing meters 1)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. ~ Some meter bases are equipped with automatic bypasses. When the meter is removed, the bypasses close and the bldg. remains energized. ~ People have developed many unique methods to bypass the meter. Structure Fires

78 78 Electrical Hazards Meters Reasons for NOT removing meters 2)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. 3)If the meter is exposed to the heat of the fire, it can build up internal stresses and explode on contact. 4)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 Fires

79 79 Electrical Hazards 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. Secure the scene until relieved by BC HYDRO. Never tamper with energized wires or equipment.

80 80 Electrical Hazards Summary Your primary responsibility is to save lives... including your own.


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