Explosion caught on video in Philadelphia.
Generators, transformers and electrical boxes will involve natural gas, propane, diesel, gasoline, hydrogen or electricity. Whether it's a propane powered generator used for backup power in a commercial building, or a roadside electrical box, use extreme caution and first determine what you are dealing with. Handle an electrical fire inside a power shelter like a class C fire. Deenergize and extinguish fire with a fog pattern or class C extinguisher. For gasoline or diesel powered generator fires, handle like a class B fire.
Sources of carbon monoxide in the home.
Fire departments respond to over 100,000 CO incidents a year and rising. Most of these incidents occur during winter months, the common heating season. Roughly 90% of CO incidents occur in residential properties where occupants are using the many appliances that produce carbon monoxide such as stoves, hot water heaters, furnaces, dryers, kerosene heaters and space heaters. Other sources of CO in the home can come from automobiles, motorcycles, lawn mowers, natural gas/propane refrigerators, charcoal or gas grills, fireplaces, gas logs, wood and coal stoves or any equipment that burns fuel.
Carbon monoxide is a toxic, colorless, odorless gas that is a product of incomplete combustion of organic matter due to insufficient oxygen supply to enable complete oxidation to carbon dioxide. CO is associated with over 500 deaths a year; 60% by auto, 40% associated with consumer products.
CO has a vapor density of 0.97 which is close to ambient air meaning that CO will readily travel throughout an enclosed structure. If doors and windows are open to the outside, the CO will disperse outdoors. The fire department can ventilate CO after identifying the source of CO and securing its release.
CARBON MONOXIDE- LEL: 12.5% UEL: 74%
When arriving to an alarm for a residential CO activation, determine if any occupants are having symptoms associated with CO exposure. They typically include headache, nausea, dizziness, vomiting, weakness, altered mental status and even death. If this is the case, call for EMS/ALS and additional manpower. The IDLH for CO is 1200 PPM. Most humans will collapse and die within a minute of 12,800 PPM exposure, 10-15 minutes of 6,400 PPM exposure and 30 minutes of 3,200 PPM exposure. Enter the area wearing an SCBA and take readings with a CO meter and attempt to locate the source.
TIP: Carbon monoxide mainly causes adverse effects in humans by combining with hemoglobin to form carboxyhemoglobin (HbCO) in the blood. This prevents hemoglobin from carrying oxygen to the tissues, effectively reducing the oxygen-carrying capacity of the blood, leading to hypoxia. High risk groups include infants, the elderly, pregnant women, and anyone with a previous history of cardiac insufficiency or chronic obstructive lung disease.
If the occupants are not exhibiting and symptoms and CO readings are below 9 PPM, evacuation is not necessary.
If readings are above 9 PPM and a source was identified, secure that source and ventilate until readings are below 9 PPM. If a reading was above 9 PPM and a gas appliance was shut down by fire personnel, request the utility company to respond.
CO detectors are designed to activate at exposures below those at which symptoms occur, however CO levels can build up quickly. CO alarms usually do not activate when readings are below 30 PPM. Most CO detectors manufactured after 1998 will activate when exposed to 30 PPM for 30 days, 70 PPM for 1-4 hours, 150 PPM for 10-50 minutes, 400 PPM from 4-15 minutes and levels above 5000 PPM. CO detectors may also activate when levels of methane, butane, heptane, ethyl acetate, and isopropyl are detected. (See below)
Many CO alarms are false alarms caused by faulty detectors or low batteries. These will be evident when 0 readings are present or a change battery beep is alerting the clueless occupant. Advise occupants to replace their battery or get a new CO detector, and inform them that unlike smoke detectors, many CO alarms do not reset immediately; they take some time.
OTHER GASES MAY SET OFF CO DETECTORS: Personnel also need to be aware of the limitations and interferences that can affect CO detectors. This may allow other gases to set off a CO detector. CO detectors are electrochemical sensors and detect a variety of specific gases. Gases of similar molecular size and chemical reactivity may produce a false positive response. The major ones are acetylene, dimethyl, sulfide, ethyl alcohol, hydrogen cyanide, hydrogen sulfide, isopropyl alcohol, mercaptan, methyl alcohol, propane, nitrogen dioxide and sulfur dioxide. Be on the lookout for these on those return calls where no apparent source of CO is found.
ALSO: Check attached garages or any nearby vehicles running. Examine flues, vents and chimneys for blockage. Check furnaces, generators and ranges for loose parts/malfunctions. Moisture inside the windows is a clue that CO may be present.
Carbon Monoxide Explosions- Click Here
35 ppm (0.0035%) Headache and dizziness within six to eight hours of constant exposure
100 ppm (0.01%) Slight headache in two to three hours
200 ppm (0.02%) Slight headache within two to three hours; loss of judgment
400 ppm (0.04%) Frontal headache within one to two hours
800 ppm (0.08%) Dizziness, nausea, and convulsions within 45 min; insensible within 2 hours
1,600 ppm (0.16%) Headache, increased heart rate, dizziness, and nausea within 20 min; death in less than 2 hours
3,200 ppm (0.32%) Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.
6,400 ppm (0.64%) Headache and dizziness in two minutes. Convulsions, respiratory arrest, and death in less than 20 minutes.
12,800 ppm (1.28%) Unconsciousness after 2–3 breaths. Death in less than three minutes.
When responding to a reported LPG barbecue grill fire involving a propane tank, the first arriving company concerns should be exposures and the possibility of a BLEVE occurring. On arrival the gas grill fire may turn out to be a grease fire or food burning with no threat to the propane tank. It's possible the hose leading to the tank regulator may be burning and the flame is being fed by the propane from the tank. These can easily be handled by extinguishing the fire with an ABC fire extinguisher or water can, removing the oxygen by closing the lid of the grill, and then shutting the propane tank off (righty tighty).
Stretch a handline to protect exposures such as exterior siding, overhead awnings or a deck. Use a 30° fog pattern in the vapor space of the propane tank if threatened by flame impingement.
Never extinguish an unisolated pressure fed flammable gas fire (unless the fuel source can be isolated). Leaking gas can migrate away from the container and may find an ignition source.
If there's no fire visible and it's only an LPG leak (detected by smell of ethyl mercaptan odorant) eliminate any sources of ignition (pilot burner, cigarettes, lighter, electric motors, switches, flares, static discharges, cell phones) evacuate anyone in the area and ventilate nearby structures using PPV. Use a CGI (Combustible Gas Indicators) to determine the level of flammable vapors in the area, determine the source and control the release. Take readings in nearby structures and basements as a precaution. REMEMBER: Propane is heavier than air and will settle in low areas. (Propane vapor density is 1.52 at 60°F.)
TIP: Propane flammable range is 2.15 - 9.60. Each cubic foot of liquid propane will boil off 270 cubic feet of propane vapor.
Any decision to approach a propane tank showing direct flame impingement on its vapor space must be made on a case-by-case basis after evaluating the hazards and risks and determining if an adequate water supply has been established.
If you arrive to hear a jet engine sound, evacuate anyone in the area, stretch a line and prepare to take cover. The relief valve has activated and a high pressure flame should be visible. Most likely the cylinder valve connection is cross-threaded or leaking. Any flame impingement on the vapor space will heat the propane tanks shell; the tank will have to be cooled to prevent a BLEVE. From a safe area such as the corner of the home or a garage, wearing full PPE, cool the cylinder with a line before approaching to shutoff the flow of propane gas or play it safe and just cool the tank and let the LPG burn off. Again, decisions must be made on a case-by-case basis as tanks can fail within minutes of direct flame impingement.
Firefighters should be aware that a functioning PRV (Pressure Relief Valve) on a burning propane tank is not a reliable indication that the tank is safe to approach or a reliable indicator of when or if the tank may fail.
TIP: A propane tank contains liquid and vapor. Fire heats the tank shell in the vapor space area more rapidly than the liquid area. By the time steel reaches 1,800°F it has lost 90% of its strength. A propane tank will eventually relieve pressure either through a split in the tank in form of a jet flame or the container fails. In most cases, the PRV will function early in the fire.
If the valve handle has melted away, a pair of vise grips can be used to shut the valve, BUT it would be much safer to just let the gas burn off while cooling the tank from a safe distance.
Propane Barbeque Grill Fires
Propane (LPG) Vehicles, Transport Vehicles, Forklifts
Don't forget service lines in the rear...
A minute later...
At 3:45 watch the service line. You know it's coming, luckily there weren't firemen in its path. REMEMBER, if this line comes down contacting the fence, the fence is energized.
This fire occurred during hurricane Sandy. Wires down whipping all over the place in high winds intensifying the fire.
Firefighters, especially DRIVERS seeing fire blowing out of the front windows should ALWAYS watch the service line on approach (and when making front entry).
Pole attached solar units are comprised of a solar panel, micro-inverter and a communication module mounted on a racking system.
Fire department response for incidents involving photovoltaic (PV) solar panels can vary. In urban areas PV solar panels are located on the roofs of parking garages, car ports, residential, high rise and commercial buildings. Adding to those structures, there are hundreds of solar panels mounted on utility poles. Firefighter concerns for solar panels will be electrical hazards and vertical ventilation. The added dead load to the roof, access points, shock hazards from cutting near the panels and the absence of a roof ladder, in addition to energized panels and toxic chemical inhalation from burning panels. For extinguishment on an energized solar panel use a CO2 extinguisher or 30° fog pattern from at least a 25 ft distance. Thermal panels are much heavier than PV panels and add a live load to the roof.
Securing the disconnect will not de-energize solar panels themselves when exposed to sunlight. They will have to be covered by a tarp. In addition, backup batteries may be present. For more in depth information on solar panels, click the links below and watch the VIDEO below on the hazards of solar panels.
Firefighters should look for an inverter or conduit during their quick first site assessment.
Solar panels on apartment roofs will make ventilation difficult for ladder companies.
VIDEO: Dangers of solar panels.
Responses to electrical fires in outlets/receptacles will usually require a Class C extinguisher, a thermal imaging camera and a dry line stretched by the engine company as a precaution in case any nearby combustibles ignite or there's fire in the wall. The ladder company will open the wall, check for extension and secure the power at the electric panel.
TIP: Some burning wire insulation contains PVC and may give off hydrogen chloride gas. In buildings that house a transformer, the coolant oils may contain polychlorinated biphenylis (dielectric & coolant fluids), giving off carcinogens as they burn.
Fires in cheap power strips with no surge protectors are very common.
This overloaded power strip burned this mans home down.
Fire at the Dallas IRS building from an overloaded power strip.
There are approximately 30,000 electrical fires in the U.S. every year. Most electrical fires are caused by faulty outlets, wiring, frayed cords, overloading outlets/power strips, lamps, faulty appliances, overloading extension cords or running them outdoors and under carpets. Others are caused by lightening strikes, water from a window AC unit contacting the receptacle, human error or just plain stupidity. Using a loaded power strip 'Made in China' with a fictitious 'UL' label on it plugged into a 125V-15A receptacle will likely cause an electrical fire.
A GFCI (Ground Fault Circuit Interrupter) protects us from shock. It monitors the amount of current flowing from hot to neutral and if there's any imbalance, it trips the circuit and cuts off the electricity. Because a GFCI detects ground faults, it can also prevent some electrical fires by interrupting the flow of current. Not all GFCI's are invincible to catching fire, but it's extremely rare.
ELECTRICAL OUTLETS, GFCI's, POWER STRIPS
When responding to a reported 'electrical' odor in an office building, business, school, library or other occupancy where numerous fluorescent lights are present, there's a good chance it's an overheated light ballast. Firemen recognize the signs of an overheated ballast by its odor or the slight haze present near the fixture. Using a thermal imaging camera can also help identify an overheated ballast. Shut the lights off, secure power and disconnect the wires leading to the ballast (located in an encased metal box attached to the reflector hood) before it gets hot enough to ignite any nearby combustibles. Remember to secure the power supply to the lamp before you work on it and leave the fixture in a safe condition) Some older lights contains PCB's (dielectric fluid) so make sure gloves and PPE are worn when working around the light fixture and ballast. For more on ballast hazards, click on the links below.
Fluorescent Light Ballast Hazards
COMING SOON: GAS AND ELECTRIC
Indoor Station Hazards (Power Substation Explosion - Indoor)
Fires in indoor stations are caused by some of the same substation-related hazards as switchyards and control rooms. The impacts of any fires involving oil-insulated equipment, oil-insulated cable, and HVDC (high-voltage dc) valves in an indoor station can result in major fires, with accompanying large asset losses and service disruptions. The basic problems with major fires in indoor stations is that the building will contain the blast pressure, heat, and smoke, and which can result in blast and thermal damage to the building structure and smoke damage to other equipment (corrosion damage).
Reference: Don Delcourt, BC Hydro
The risk of fire in substations has been historically low, but the possible impacts of a fire can be catastrophic. Fires in substations can severely impact the supply of power to customers and the utility company’s revenue and assets. These fires can also create a fire hazard to utility personnel, emergency personnel, and the general public. The recognition of the fire hazards, the risks involved, and the appropriate fire-protection mitigation measures are some of the key considerations for the design and operation of new or existing substations. There are a wide range of types and causes of the fires that can occur in substations.
The types of fires depend on the equipment and systems used in the stations. Fires involving dc valves, outdoor or indoor oil-insulated equipment, oil-insulated cable, hydrogen-cooled synchronous condensers, or PCB-insulated equipment are usually well documented, and these types of equipment are easily recognized as a fire hazard.
There are a number of other substation-specific types of fires that are not as well documented.
Energized electrical cables with combustible insulation and jacketing can be a major hazard because they are a combination of fuel supply and ignition source. A cable failure can result in sufficient heat to ignite the cable insulation, which could continue to burn and produce high heat and large quantities of toxic smoke. Oil-insulated cables are an even greater hazard, since the oil increases the fuel load and spill potential.
The hazard created by mineral-oil-insulated equipment such as transformers, reactors, and circuit breakers is that the oil is a significant fuel supply that can be ignited by an electrical failure within the equipment. Infiltration of water, failure of core insulation, exterior fault currents, and tap-changer failures are some of the causes of internal arcing within the mineral insulating oil that can result in fire. This arcing can produce breakdown gases such as acetylene and hydrogen.
Depending on the type of failure and its severity, the gases can build up sufficient pressure to cause the external shell of the transformer tank or ceramic bushings to fail or rupture. Once the tank or bushing fails, there is a strong likelihood that a fire or explosion will occur. A possible explosion could cause blast damage. The resulting oil-spill fire could spread to form a large pool of fire, depending on the volume of oil, spill containment, slope of the surrounding area, and the type of the surrounding ground cover (i.e., gravel or soil). Thermal radiation and convective heating from the oil spill fire can also damage surrounding structures and structures above the fire area.
Substations are exposed to the common industrial fire hazards such as the use and storage of flammable compressed gases, hot work, storage and handling of flammable liquid, refuse storage, presence of heating equipment, and storage of dangerous goods. The local fire codes or NFPA codes can provide assistance in recognizing common fire hazards.
Some of the specific components encountered in substation switchyards that are fire hazards are: Oil-insulated transformers and breakers, oil-insulated potheads, hydrogen-cooled synchronous condensers, gasoline storage or dispensing facilities, combustible service building, storage of pesticides-dangerous goods, warehouses & standby diesel-generator buildings.
The failure of some of the critical components such as transformers and breakers can directly result in losses of revenue or assets. Other switchyard components could create a fire exposure hazard to critical operational components (i.e., combustible service buildings located close to bus support structures or transmission lines).
Control and Relay-Building Hazards. A control or relay building can include the following potential hazards:
*Exposed combustible construction
*Emergency generators, shops, offices, and other noncritical facilities in the control buildings
*Batteries and charger systems
*Switchyard cable openings that have not been fire-stopped
*Adjacent oil-insulated transformers and breakers
A fire in any of these components could damage or destroy critical control or protection equipment. Damages could result in a long outage to customers as well as significant revenue losses.
If the LPG powered vehicle is heavily involved in fire, prepare for a possible BLEVE. Evacuate the area, request police for traffic control and from a maximum and safe distance, protect any exposures from the vehicle fire or pressurized flame coming from the vehicle (although rare, the PRV can fail). When the PRV is properly activated, it should not be an indicator that a BLEVE will not occur. After a risk/benefit analysis, unless there's an occupant trapped in the burning vehicle or in immediate danger, let the LPG burn off; the vehicle can be replaced.
LPG powered passenger vehicles must have their PRV's vented to the outside of the vehicle. They are required by NFPA 58 to be identified with a diamond shaped label on the lower right rear of the vehicle with the letters "PROPANE" on the silver or white reflective badging.
If called to investigate an odor of propane gas in a parking garage or parking lot, check to see if there are any LPG vehicles. Once identified, use CGI's to investigate the source and obtain readings. Evacuate people from the area, control ignition sources, identify the source of the leaking propane and stop the leak if it can safely be done. The fuel tank will usually be in the trunk, which is where it's possible that flammable gas has accumulated. The trunk will need to be opened to access the tank valves and fittings.
DISCONNECT THE BATTERY before you open the trunk. The contact switch for the truck light is a potential source of ignition.
This vehicle fire has obvious signs of a tank in the bed of the truck. It's relief valve and pressurized flame is clearly visible. Watch explosion at 1:55.
Phila PA: A food truck explosion occurred when leaking propane found its ignition source in the grill killing a mother and daughter.
TIP: Propane pressure regulators are designed to control propane vapor pressure. They reduce the higher gas vapor pressure inside the storage container to a lower and more constant pressure, which is necessary to operate gas appliances like heaters, stoves, safely and efficiently. NFPA 58 requires the use of two-stage regulator systems for most fixed installations in buildings. NFPA also requires that all 20lb cylInders be equipped with an OPD (Overfill Protection Device).
How many propane tanks are located in your response area?
Considering propane tanks supply LPG to barbecue grills, forklifts, heaters, cars, buses, sanitation trucks and RV's, there may be hundreds of propane tanks in your first response district. Larger LPG storage tanks are located at commercial businesses (hardware stores, gas stations) industrial areas and underground. Many 20 lb propane tanks are illegally disposed of in dumpsters and vacant lots. Firefighters arriving to a dumpster fire should assume that hazardous materials may be present. Although propane emergencies and BLEVE's are rare occurrences, preparing for them can save the lives of firefighters.
Gas leak in garage caused when homeowner accidentally drove his car into the gas meter. Click here for the radio audio.
Natural Gas Escaping Outside: Apparatus placement is critical on natural gas calls. Gathering additional information from the dispatcher is beneficial (knowing that working construction crews may have hit a gas main will be very helpful information). Approach the area upwind or outside the plume and avoid parking over manholes. Evacuate the area and check any adjacent structures for gas. Have police respond and keep vehicle traffic away from the area. Establish a hot zone, eliminate all ignition sources and have the utility company respond. If any construction/excavation equipment is running, do not turn it off. In some instances, it may be necessary to use a hoseline with a fog pattern to move escaping gas away from hazardous areas, such as other structures that may provide an ignition source. Extinguish any nearby flames if burning combustibles are present and gas is still releasing. If a curb key can stop the leak, do so if it can be done safely. Once something is shut, leave it off!
VIDEOS INVOLVING NATURAL GAS EXPLOSIONS
For CNG powered motor vehicles (RV's, Sanitation Trucks, Transit Buses, CNG Cars) click here.
Upon arrival of the first fire due engine, firemen found a fully involved fire in a camper trailer with propane tanks venting and the fire extending to a garage and extreme heat conditions threatening a residence. Firemen were able to quickly control fire and extinguish the fire approximately 20 minutes after arrival. Quick action by fire department personnel prevented the fire from extending to the residence and the possibility of an explosion of the propane tanks.
Be careful when approaching a fire involving an RV. The propane tanks can be anywhere including under the vehicle. Use caution and locate them to see if the relief valve has activated or fire is threatening the tanks.
DO NOT always assume that the activation of a relief valve will prevent a BLEVE. See VIDEO below.
Fire departments are seeing an increased amount of incidents involving gas and electric. Some common responses involve:
*Natural gas and propane leaks.
*Carbon monoxide alarms.
*Diesel and gasoline spills.
*Downed power lines.
*Fires involving manholes and transformers.
*Sparking outlets, circuit breakers and water leaking into light fixtures.
*Solar panel and switch station yard emergencies.
*Overheated light ballasts and wires burning (electrical fires/smoke conditions).
*Energized service lines exposed to fire.
It's important for firemen to understand the dangers of electric and gas and mitigate the minor incidents while notifying the proper resources during more dangerous and complicated incidents. Fire department personnel are not on scene to act as electricians, appliance repairmen or employees of the local gas company.
This explosion engulfed a forklift with the operator barely escaping with his life. See the full story and more video at The Blaze.
TACTICAL OBJECTIVES: The primary tactical objective is to cool the outside of the portable cylinder protecting the shell and reduce the pressure to the point that the pressure relief valve closes and the cylinder valve can be manually closed. The secondary objective is to protect exposures, extinguish any structure fires, check for extension and monitor nearby structures for propane gas.
This propane tank fire was caused by a cross threaded hose connection. The leaking gas caught fire and raged around the tank outlet. The tank was connected to a grill that was up against the home, causing the siding to melt. An 1 3/4 hoseline with a fog nozzle should be used to go back and forth cooling the tank and extinguishing the exposed siding of the house until a second line is in service.
If upon arrival to a gas grill propane tank fire with exposure to the home you notice the relief valve is activated and the jet engine sound is present, KEEP BACK a good distance and cool the tank from an area of protection such as the side of a house, behind a garage or large vehicle. If the home is starting to catch fire, go for a 2 1/2 line for more reach from the safer distance. Upgrade the incident to a full structure assignment and request Hazmat response.
Click here to see explosion
Natural Gas Escaping Inside and Burning Inside: Protect interior exposures and combustibles using hose streams and water spray. Shut off natural gas at the source IF IT CAN SAFELY BE DONE and extinguish any remaining fires. If it can't be done, the utility company can secure the gas at the meter or the street. DO NOT extinguish the fire before the gas has been shut off. An explosion can occur as the accumulating natural gas is ignited by a nearby ignition source.
About 11,000 people were left without power after fire broke out at this Dominion Power substation in Churchville Virginia.
Engine 47 found a large transformer at the Dominion Power substation on fire. Dominion Power sent a supervisor who had the electricity cut off and allowed firefighters to attack the fire with foam, quickly knocking it down. The transformer contained approximately one thousand gallons of mineral oil. Approximately 11,000 persons were without power until workers could re-route power and set up a temporary transformer.
How many calls will the average firefighter respond to during their career for a propane leak or fire involving a forklift? These are extremely rare incidents, but they do happen. First arriving crews must carefully determine whether the propane tank is involved, rescue priorities, protecting exposures, evacuating employees, and requesting additional resources if needed.
Forklifts are powered by motor fuel service propane cylinders that are usually configured to supply liquid propane to the engine rather than the vapor. They can have as many as five openings in the service end of the cylinder. Fittings may be threaded or flanged. Each service valve opening is marked for either vapor or liquid service. Most cylinders are equipped with a PRV (Pressure Relief Valve) set to function at 375 psi.
If the forklift is on fire and the tank threatened, stretch two 1 3/4 handlines and cool the tank while extinguishing any fire involving the forklift. Wet any exposure combustibles if necessary. Keep a safe distance, evacuate any workers nearby and let the LPG burn off while cooling tank from maximum distance. Extinguish the fire involving the forklift (NOT THE TANK!) and apply a 30° fog at the vapor space for several minutes before making any decision to approach and close the tank supply. Contact the local propane marketer for technical assistance in removing and disposing the cylinder.
Motor fuel cylinders can rupture under fire conditions even if the PRV (Pressure Relief Valve) is not functioning.
Close Call: Watch Propane Explosion During Fire In Maine-Click Here.
Propane is often carried on motor vehicles from transport trucks, LPG alternative fuel vehicles, forklifts, buses, food trucks and RV's. First arriving officers should suspect propane tanks on RV's, forklifts and food trucks. Transport trucks with large storage tanks are obvious, and LPG passenger vehicles have badging placards on the back (above left). But some vehicles could have 20lb LPG tanks located in the trunk or bed of their pickup trucks. Unsuspecting firemen may be approaching a dangerous situation if they're not aware of hidden propane tanks being heated during a vehicle fire. One sign is an activated relief valve or pressurized flame with a loud jet engine sound.
Always be cautious when approaching vehicle fires. If the occupant is present, ask him/her if there are any gasoline/propane tanks or any other hazardous materials in the trunk. Be suspect of tanks in dumpsters, garages, sheds and basements as well.
Food truck explodes during a football game. Leaking propane from a food truck will easily come into contact with an ignition source if not detected.
What is propane?
Propane and butane are the two major LPG gases extracted and used in the gas industry. About 70% of propane is processed from natural gas. Propane is colorless and odorless in its natural state but a commercial odorant is added so it can be detected if it leaks. The most common used odorant is ethyl mercaptan.
LP-gases belong to a family of chemical compounds known as alkane hydrocarbons, meaning they are made up of hydrogen and carbon atoms only. Propane is 1.5 times heavier than air.
The combustible materials in propane are carbon and hydrogen (hydrocarbons). The oxygen needed to burn propane vapor is obtained from the air. Air is made up of 20% oxygen, 79% nitrogen and 1% other gases. Any ignition source must provide enough heat to the mixture of fuel and oxygen to raise the temperature of the propane to its ignition temperature, which is between 920°F and 1,120°F. The flammable limits (explosive range) for propane: LEL 2.15% UEL 9.60%
Firefighters Battle Transformer Fire
This energized service line burned for several minutes without coming down. That doesn't mean the next one won't. Take these service lines into consideration during apparatus placement, laddering the building and making entry through the front door.
TIP: Firefighters respond to thousands of gas leaks every year, and 95% of them are handled without incident. Being complacent on a 'routine' gas leak response can result in the deaths and serious injuries of firefighters and civilians. Watch the video below and Imagine being the IC at this incident.
Sources of Ignition: If there's an ignitable mixture of natural gas present, (4% to 15% gas in air) eliminate all ignition sources. Common sources are pilot lights, spark ignitors, electrical switches, disconnects, door bells, security systems, non-rated flashlights, pagers, radios, cell phones, static electricity and any other source over 900 °F.
If power needs to be cut from the building because of natural gas accumulation, do NOT shut off circuit breakers or pull the electric meter (may cause an arc).
*Consider the possibility that the building may have a backup generator.
NFPA: Fire departments responded to an estimated 50,000 fires per year starting with ignition of a flammable gas and another 160,000 fires per year starting with ignition of a flammable liquid resulting in an estimated 168 civilian deaths, 1,029 civilian injuries, and $644 million in property damage. The flammable or combustible liquid fires resulted in an estimated 454 civilian deaths, 3,910 civilian injuries, and $1.5 billion in property damage. Flammable gas fires nearly all involve natural gas or LP gas.
Utility pole fires are common and should be treated with great respect by firefighters. Pole fires are normally caused by the failure of insulators, switches, catastrophic failure of transformers or oil-filled switching equipment. Some poles used in the utility industry today are highly conductive as a result of preservatives used to treat the wood. The treatment also causes the poles to burn rapidly and sustain fire easily. These poles can be easily recognized by their distinct green color. When pole fires are caused by insulator or switch failure, current will be able to flow to the pole through the metal hardware components of the insulator or switch. Since the pole may be highly conductive due to the preservative treatment, dangerous levels of voltage may be present at the base of the pole. When pole fires are caused by catastrophic failure of transformers or other oil-filled equipment, the situation is compounded. Current may be leaking to the pole as in the first case, plus oil from the equipment could fuel the fire. In the above cases, the six following actions are recommended:
1. When the call is received at the station reporting a pole fire, the information should be reported to the nearest utility owning the line as quickly as possible. State the exact location of the pole. Note: This number has been put in place strictly for the use of fire and police personnel and should only be used for emergency situations.
2. On arrival at the scene of a pole on fire, firefighters or police personnel should carefully survey the situation. Do not place your vehicles under or near wires that may burn off or fall due to the fire. Set up a danger zone.
3. Crowd control is extremely important. People should be kept well away from the affected area as a caution against wires that may burn off and fall, or equipment that may explode.
4. Firefighters should hook up and stand ready to protect adjacent properties.
5. Do not apply a direct stream of water on a pole fire. A non-conductive extinguishing agent is best to control the fire should it become necessary to protect property or life. The pole is thick and will take forever to burn. Do not apply water...
A pole fire that is caused by a flow of current cannot be put out until the electricity is turned off and the flow of current stopped.
6. Electric utility personnel who respond to the scene of the pole fire will make the conditions electrically safe. When they confirm that conditions are safe, firefighters may then proceed to extinguish the fire using conventional means including water.
DANGER: When it come to downed wires, many wires have automatic lockout provisions-if a circuit breaker trips at the pole or in the plant, it should cut power to the wire. The problem is that the system is also set up to restore the power automatically. You have no way of knowing whether the power has been restored upon your arrival. Be proactive and check any nearby fences, vehicles, trees etc.. that maybe energized from contact of the downed wire and stay away from them.
SOURCE: Electrical-Engineering Portal & 'Responding to Routine Emergencies' Frank Montagna.
Manholes and Vaults:
Natural Gas Burning Outside: The best way to control an outdoor natural gas fed fire is to secure the gas flow. This is best left to the utility workers, as an explosion can occur if all precautions are not taken. If there's fire present on nearby combustibles, extinguish them with a hoseline or dry chem extinguisher if it can safely be done. DO NOT EXTINGUISH THE GAS FIRE ITSELF. Let it continue to burn. If rescue is needed, depending on the situation, fog lines may be used to dissipate the leaking natural gas until the utility company shuts off the gas supply.
Be cautious approaching suicides, landlord/tenant disputes-evictions, domestics with odors of gas present.
Natural Gas Heating Furnaces- Hot Water Heaters
CIRCUIT BREAKER FIRES, ELECTRIC DISTRIBUTION PANELS
Massive explosion caused by construction workers equipment rupturing gas line. FD Audio: Click Here
PD dash-cam records explosion in NJ.
TIP: Incomplete combustion of natural gas or other fossil fuels can produce carbon monoxide (CO). It may be neccasary to take CO readings as a precaution during some incidents.
Eight firemen and gas company worker injured in strip mall explosion in Maryland.
50 homes destroyed in San Bruno CA.
Firemen are often the first to respond to natural gas emergencies, usually arriving on scene before the utility company. These responses are often odors of gas and residential indoor gas leaks with more serious incidents involving broken gas lines and explosions. In the U.S, natural gas in commonly used for ranges and ovens, gas-heated clothes dryers, heating/cooling, and central heating. Heaters in homes and other buildings may include boilers, furnaces, and water heaters. Natural gas incidents should be treated as hazmat incidents with all responders having a basic understanding of natural gas and how to eliminate and control hazards. Most of these calls end without serious incident, but that alone can be dangerous as it can lead to complacency. (See videos below)
Natural gas is a (hydrocarbon) fossil fuel made up of mostly methane. It's colorless, odorless and tasteless in its natural state, but an odorant methyl mercaptan is added to natural gas so that leaks can be identified quickly. Mercaptan is a colorless, flammable gas that has a putrid rotten cabbage odor. Natural gas (Methane) is non-toxic, although it is an asphyxiant. It has a LEL/LFL of 5% and an UEL/UFL of 15% (or flammable range). Methane is lighter than air with a specific gravity of 0.554 and will tend to rise.
TIP: Since natural gas and propane are colorless and odorless, a small amount of methyl mercaptan or ethyl mercaptan is added to make it easy to detect a gas leak.
Gas leaks inside of a structure are often far more dangerous than outdoor leaks. It's important to gain as much information from the dispatcher when en route. Apparatus placement is extremely important. Do not park in front of the building with the reported gas leak and stay uphill/upwind and avoid parking over manholes. Notify the utility company and evacuate occupants from the structure and nearby adjacent buildings/homes. Have police block the area off to prevent traffic.
REMEMBER: Eliminate Ignition Sources. Do not ring doorbells, use elevators, turn on light switches, possess cell phones, use electric fans for ventilation, or allow anyone to smoke in the area. If a relief valve is venting or blowing, it is doing their job properly. Do not try to shut it off.
Always use meters (multiple meters) to check for gas PRIOR to entering the structure. Especially if our noses are detecting a strong odor of gas upon arrival. With low readings attempt to locate and secure the source if it can safely be done.
Natural Gas Escaping Inside: Odors of gas can come from many sources such as gasoline, propane, sewer gas etc. Attempt to identify the gas and where the release is coming from. Gas meters can help identify an appliance that can be easily shut off. Gas meters reading the LEL/UEL are used to determine the potential danger for explosion. These readings are also important for ventilation when readings are above the flammable range. Typically, firefighters can ventilate by opening windows and doors after securing the source when meter readings allow it to safely be done. Be careful not to ventilate the structure and bring the atmosphere down to the flammable range with a nearby ignition source present. With strong odors of gas present and dangerous readings on the meter, evacuate the area and wait for the utility company.
Breaker boxes are how electricity enters and is routed through your home. One large cable enters the box, and power is separated and routed through different ports and breakers for different circuits. Most are located in the basement, garage or the living area of a home. Breaker boxes are safe when certified products are installed correctly. However, unsafe products or installations are in some homes and can lead to fire inside the breaker box. Circuit breakers can overload and cause fires. Federal Pacific Electric (FPE) Stab-Lock breakers and panels are known fire hazards, now widely thought by engineers, electricians and house inspectors to be defective - and dangerous. When encountering a circuit breaker fire, use a class C extinguisher and shut off the power. Check for any extension and have an electrician (inspector) respond.