nat gas response emergencies outline.docx

Chapter 1 Routine gas leaks are not routine Strategic Summary Goal of this book is to provide the FF with a summary of what you need to know about natural gas emergencies in one Concise training manual 5 goals of this book Understand vital background information about natural gas and its delivery...

Chapter 1 Routine gas leaks are not routine Strategic Summary Goal of this book is to provide the FF with a summary of what you need to know about natural gas emergencies in one Concise training manual 5 goals of this book Understand vital background information about natural gas and its delivery system Know critical size up and strategic and tactical decision making procedures Learn considerations that can help to improve your existing gas emergencies response procedures Learn recommended procedures for 7 types of NGE Practice training methods that can enhance your officers and firefighters actions during NGE Case history Underground boring too when he hit a plastic 2”, 60 LBS NG street main NG leaked for undetermined amount of time, eventually leaked back into one of the nearby homes 2 gas techs on scene 45 minutes prior to explosion Last home closest to the leak was locked, forcible entry was needed when gas exploded Post traumatic growth is the positive side of experiences like this It can drive you to new levels of understanding, research, professionalism and to set and achieve new lofty goals. This book is a result of that experience and growth I did not know what I did not know Fill the gap for you, your company, and your department You don’t know it because you were never trained to know and understand these things 10 critical Facts I did not know Metal oxide based explosive gas will detect low levels of gas that your 4 gas will not. Always pair inexpensive metal oxide detector with 4 gas monitor to increase safety and effectiveness Gas migrated underground, driven by a 2”, 60 psi main, took the path of least resistance for up to an hour before house exploded. Start nearest the leak site and evacuate outward Not all the gas was escaping, some was migrating underground. The frost layer in the ground prevented the gas from escaping, so it took the path of least resistance into a nearby house. FDs operate at the technician and command level at NGE Forcing entry into a building containing gas and numerous ignition sources is like Russian roulette. Turnout gear will not protect you a bomb like this Gas techs are trainings to measure NG in percent volume of gas.FF measure percent of lower explosive limit (LEL) Gas tech says 10% he means 10% gas 10% to ff means only 10% of LEL Trust but verify what the gas techs are asking you to do in compliances with procedures. FD is responsible for life safety of both civilians and firefighters NY 2014 NG explosion claimed 8 lives, utility was fined $153 million Con Edison failed to adhere to nearly a dozen state gas safety requirements that contributed to explosion You have no plan B SOPs are weak, most have basic Dos and Donts but generally lack sequential procedures, forcing FD officer in command to make them up on scene Should have had an explosive gas detector with me to complement my 4 gas. It would have detected low levels of escaping gas faster than the 4 gas Life safety is the FDs mission, not to find and fix the leak. The utility’s job is to find and fix. There are no good guys and bad guys here, but there is a very different perspective for the players responding to the leak CHAPTER 2 Critical tactical considerations Flammable rage for NG is 5% to 15% gas in air Median lethal dose for NG is 53% gas in air Vapor density of NG is 0.57-0.62 relative to air Most humans can smell NG at about 1 PPM Lower flammable limit for NG is 50,000 PPM 3rd school children and teachers killed in a gas explosion are why gas is odorized today Introduction Gasses that are used to supply heat energy are called fuel gases, made up. Of hydrocarbons Hydrocarbons are made up of hydrogen and carbon atoms NG is mixture of about 96% methane with ethane, propane, butane, and some other trace gases Flammable range The correct mixture of gas in air that will ignite or explode. Flammable range for NG is 5% to 15% gas in air Air contains about 21% oxygen and most fires require at least 16% oxygen content to burn There must be at least 5% gas mixed with 95% air to ignite Gas concentration 15% in 85% air, beyond is no longer flammable or explosive Lower Flammable Limit Minimum amount of gas that is required to ignite or explode when missed with air and an ignition source at normal pressures and temperatures Exact LEL is 4.4% but industry uses 5% Upper Flammable limit Maximum amount of gas that can be mixed with air and an ignition source to ignite, if confined, explode. 15% for NG Ignition Temperature NG needs an ignition source to create a fire in the presence of air or oxygen Ignition temp of NG is 1,163F Toxicity NG is not toxic, can displace oxygen creating an asphyxiation and deadly atmosphere LD 50 for methane is 539,600 PPM for 2 hours Vapor Density NG is lighter than air, with a vapor density of 0.57-0.62 relative to air It will rise rapidly, dissipating in open air or accumulation near the ceiling inside buildings Order and detection levels NG has no odor, it is odorless, colorless, and tasteless Regulations require it to be odorized so that is is readily detectable by a person with a normal smell at a concentration in air of one fifth of the LEL LEL of NG is 5%= 50,000 PPM. Therefore one-fifth of 50,000 PPM is 10,000 PPM Remember odorant can be scrubbed out of NG if gas passes through soil New London Texas School explosion killed 298 students and teachers Required gas to be odorized as a result Also requested all distribution company pipes and some transmission lines Most common odorants is mercaptan, rotten egg, sulfur or garlic like smell Raw unpurified NG coming out of the earth at a well has a different smell depending on the area of the country NG near gas fields can be more like automotive gas Odorant is detectable at 0.002 PPM by most humans Mindset needs to change to all gas calls are extremely dangerous until proven they are not Tactical actions to improve gas leak responses Life safety is the FD mission Identify the Kill Box in the area Erg defines the danger zone for compressed gases as 100 m or 300’ Park outside of the kill box Limit the number of firefighters in the kill box Evacuate civilians as necessary and as quicklu as possible if life safety is a concern. Evac is the primary FD mission, not to find and fix the leak Students exposed to about 4 ppm of methyl mercaptan for several hours experienced headaches ans nausea At 4 PPM people get sick and are symptomatic 2 facts to consider when building is locked 1- if the building contains flammable or explosive amounts of NG FF have no plan B 2-has anyone ever been or ever heard of on being overcome by NG 2019 Farmington, Maine, approx 400 gallons of liquid propane leaked from a backyard tank making its way into the basement of a nearby building. Contractor nicked the underground propane supply and gas migrated through the soil over the weekend. FF entered the building, despite hand held meters sounding because there was no odor and they assumed the alarm was caused by malfunction Explosion killed 1 Capt and severely injured 7 others Town had to pay $22,000 in fines for failure to ensure ff had proper training and equipment Natural Gas components The molecular structure or chemical composition of NG is the physical atomic makeup of various molecules that compose the mixture we refer to as NG Single largest contributor is methane Common Hydrocarbons found in Natural Gas As the ratio of carbon to hydrogen atoms increases, the heat released by the burning of the gas increases Typical makeup of Natural Gas Heavier gas release a greater amount of heat or BTUs per cubic foot of gas NG is becoming more popular because its one of the cleanest burning fuels and comes in manny different forms, compressed and liquefied states Where does NG come from Decompositions of formerly living material The heating value of NG is measured in BTUs and therms (standard gas billing unit) Purification One the NG has been removed from the ground the gas is purified through partial condensation to remove contaminants, also known as condensables Remaining compounds give the NG; odorless, colorless, tasteless, nontoxic, and nonpoisonous CHAPTER 3 Most frequent area of gas escape is the residential or commercial occupancy Residential A common mandatory evacuation level is 10% LEL A combustible gas in a distribution line must contain a natural odorant or be odorized so that a concentration in air of one-fifth the lower explosive limit Key components of a residential gas distribution include A curb box- quarter turn valve usually buried in the lawn of residence Purpose is to open or close the flow of gas from the main into the service line Curb boxes are valves for specific gas customers, not street valves that control the flow of gas in gas mains Service line- buried pipe that connects the gas distribution main to the customers riser ¾” to 1” in diameter Plastic pipe and designed for same pressure as the main ; 0.25-99 PSI Located close to surface of lawns and driveways Riser- raises the service line up from underground to the service valve Must be made of galvanized pipe because it is more durable than plastic Piping used outside the building must be galvanized Excess flow valves limit gas flow if the service line or meter is damaged Automatically restricts the flow of natural gas if an underground pipe is broken May prevent the buildup of natural gas and lessen the possibility of personal injury and/or property damage Some installations( mostly residential) will have an excess flow Val use that will limit gas flow if service line is damaged. There will not be found on apartments or commercial services Pressure regulator is a diaphragm based device that steps down the pressure from service line and main pressure Convert street pressure (5-99 psi) to about 7” of water or 0.25 PSI Designed with a fail safe and will release gas through the vent at the bottom of the regulator An indoor meter with outdoor valve and regulator is another common setup you Amy see, with this set there will NOT be a curb valve If you see a wall vent, the meter is inside. The vent is piped to dump gas outside if the regulator fails Shutting off the gas meter with a gallivanting tool is a firefighter level skill1 Quarter turn to the left The meter itself is how the gas sustainer is charged for the gas consumption The half foot dial hows if moving gas is moving past the meter If significant leak or gas consumption, it will be moving quickly PIPING INSIDE THE HOUSE The POE is critical for gas piping and other utilities, which can be a way for fugitive gas from an underground leak to enter a building and cause a life hazard. This location is often a route of entry for escaping gas (from service line or main) to enter the building from either damage to the outside meter set or an underground leak remote from the building. Recall that the gas can migrate through porous block and cracks in the foundation as well. Interior residential piping splits to provide gas to the boiler and hot water heater in the basement and to other appliances upstairs. Note the quarter turn valve used to isolate certain sections of the in-house piping. Be careful when operating these valves because they can easily break; many times, they may also be the cause of the leak. Flex lines allow appliances like clothes dryers and stoves to be moved out for cleaning and service. Often repeated moving and flexing of this line creates a small crack or other damage, which results in gas odor calls for us. It is important to note that a flex line is not CSST. TYPES OF PIPE You will encounter two main types of pipe CSST should not be confused with fuel gas flexible appliance connectors CSST is used in place of rigid pipe to supply gas to appliances inside buildings CSST is tested to national standard ANSI LC 1, which is different from the standard for flex able connections. Flexible connectors are used to attach moveable appliances to the gas piping system CSST is typically yellow-clad and sold in 75' coils. The inside diameter is ¾" Generally, this tubing is trouble-free, but it is not nearly as durable and damage resistant as rigid iron pipe. Yellow indicates the standard CSST fuel line used instead of rigid pipe the black-coated version has an arc-resistant jacket Black-jacketed CSST products have been tested and listed according to ANSI LC 1, Section 5.16. Thus, an arc-resistant jacket or covering system may not require or include instructions for the additional direct-bonding (electrical grounding) step that is required with standard yellow CSST products One problem with CSST is that it has to be grounded effectively to prevent damage from direct or nearby lightning strikes that can cause electrical arc burns (holes in tubing), releasing gas When responding to potential or actual lightning strikes, Ask occupants early on in your size-up and always follow up with your meters. CSST is being used in multiple dwellings Case History The Origin and Cause Investigation of the fire at 7005 Woodscape Drive incident, conducted by the HCDFRS Office of the Fire Marshal, determined the area of origin to be the unfinished basement crawlspace below the first-floor family room and breakfast area. Investigators identified the ignition sequence of the fire to be a lightning strike which induced the failure of the residential [CSST] system. This caused the ignition of fugitive gas escaping from the hole formed by the arcing process which then ignited combustible material in the area of origin. On smaller apartment, condo, or co-op buildings, you may find multiple residential meters. Each meter or customer at this four-unit apartment has its own shutoff, but it is often dificult to determine which meter serves which apartment. There is also one shutoff that will cut off gas flow to all the meters. The common pressure regulator is right above the shutoff Shutting down unnecessarily could be very costly to the customer. When possible, shut down gas supply as close as safely possible to the leak or appliance. Gas explained gas from the gas main enters the meter and regulators at the “service valve” at a pressure of 50 to 75 pounds per square inch (psi) or higher. This is the valve that is most important to close if we are ordered to shut off the gas to the building. This valve has a ring cast onto the side of its body and the square or rectangular head on the valve has a tab with a matching ring. When the ring on the head is in line with the pipe, the valve is open. A quarter turn of the head of the valve will close the valve; line up the ring on the head with the ring on the body so that a lock or seal can be applied to prevent the valve from being opened. Gas mains and distribution systems Local distribution companies (LDCs) own and operate the gas mains and supporting valves, piping, and regulator stations Gas distribution systems operate at pressures ranging from 0.25–99.00 psi and consist of mains, services, valves, and meters that are constructed of steel, cast iron, ductile iron, wrought iron, or plastic, depending on the system age and type of service. NG transmission and distribution piping system installations must conform to rigid construction requirements set forth in ANSI B31.8, Gas Transmission and Distribution Piping Systems The US Department of Transportation (DOT) maintains jurisdiction over the safety of transmission pipelines, and distribution systems must comply with DOT regulations, along with any public utility commission requirements. Utility companies must ensure the integrity of their NG distribution systems through a comprehensive safety program that involves regularly scheduled surveying, monitoring, maintenance, and testing Propery owners are responsible for all NG piping inside buildings downstream of the meter. Most utility companies are responsible for the entire distribution system, including the NG meter We tend to think distribution mains are always bured under the road surface and inour minds eye, under the middle of the road. May not always be true The First and most expected possibility is within the roadways and streets Most older cities with right streets and limited set-backs, all the utilities will most likely be found under the roadway or sidewalks In larger areas, The locations of the utilities are typically given greater offsets. Main lines for water, sewer, and gas can typically be found within the footprint of the roadway or just off its edge. In established areas within towns and counties that have had utilities installed after the construction of the roads, utilities such as gas and water will be placed within existing or new easements outside of the roadway. At pressure regular distribution system, FDs should not attempt any actions in pressure regulating stations In a vent stack, which is where NG will release when there is an over-pressurization in the gas mains. If it is releasing gas, do not restrict the flow or apply water to attempt to dissipate the gas. Like with any relief valve, let it do its job. The box is the “chart,” which has monitoring capability and sends information to the Gas System Controllers LDCs receive NG from transmission pipelines and distribute it to commercial and residential users Distribution pipelines are generally smaller in diameter than gas transmission pipelines and operate at reduced pressures Distribution systems consist of mains that are normally installed underground, along or under streets, roadways, and smaller service lines. The point at which the local distribution system connects to the NG transmission pipeline is known as the city gate At the city gate, the gas pressure is lowered and a sour- smelling odorant is added to the gas to help users detect even small quantities of leaking gas Maximum allowable operating pressure (MAOP) is the maximum internal pressure at which a pipeline or pipeline segment may be continuously operated The actual operating pressure will vary along the pipeline, depending on terrain, elevation, and distance from a compressor station Low pressure distribution systems are around 14" of water column or about 0.5 psi. According to PHMSA, “A low-pressure distribution system is a pipeline system designed and used for distributing NG, and is characterized by the gas pressure in the main being substantially the same as the pressure provided to the consumer.” Since this is low pressure, there are no pressure regulators on customer meters. Medium pressures vary from 25–33 psi and use pipes of steel, plastic, cast iron, ductile iron, and wrought iron components will have a pressure regulator at the customer’s building High pressure systems in the 99-psi range and use only steel pipe and select plastic pipe materials. A high-pressure distribution system is an NG distribution system in which the gas pressure in the main is higher than the pressure at which gas is provided to the customer Valves and Valve Placement a valve is a mechanical device installed in a pipeline and used to control the flow of gas If a pipeline should fail, how quickly the valves can be closed and the distance between the valves are some of the main determinations for how much fuel is released. Grades of Leaks Gas industry uses a classification system for severity and danger of existing leaks Essentially the most dangerous leaks are those that mitigate toward or into buildings, creating obvious life safety and property hazards Grade 1 A leak that represents an existing or probable hazard to persons or property, requiring immediate repair or continuous action until the conditions are no longer hazardous. The utility will work continuously until the repair is made. Grade 2 A leak that is recognized as being nonhazardous at the time of detection, but justifies scheduled repair based on probable future hazard. The utility is required to maintain periodic surveillance of these to ensure they do not become a threat to life or property Grade 3 A leak that is nonhazardous at the time of detection and can be reasonably expected to remain nonhazardous. These are the grades of leaks that by regulation can allow to remain for long periods of time. The FD is often called back to the same location when civilians smell the odor of gas at what has been designated a grade 3 leak Gate Stations When the natural gas in a transmission pipeline reaches a local gas utility, it normally passes through a “gate station Gate stations serve three purposes. First, they reduce the pressure in the line from transmission levels (from 200 up to 1,500 pounds) to distribution levels, which range from ¼ pound to 200 pounds. Then an odorant, the distinctive sour scent associated with natural gas, is added, so that consumers can smell even small quantities of gas. Finally, the gate station measures the Yow rate of the gas to determine the amount being received by the utility From the gate station, NG moves into distribution lines or “mains” that range from 2" to more than 24" in diameter Generally speaking, the closer NG gets to a customer, the smaller the pipe diameter is and the lower the pressure Raw Processing Plant Raw gas from the well and gathering sites is processed to remove contaminates and to provide a consistent quality NG to consumers. Undesirable components are described as condensable These condensable are removed by small changes in temperature or pressure They are removed because they contain water and sulfur. Combining the two creates a very corrosive compound when in the proximity of hydrocarbon compounds found in NG The removal of water and the condensables from NG helps to prevent corrosion of the transmission pipelines that are used to transport the NG to the various distribution companies The beginning of the gas gathering and transmission system is at the NG Velds and wellheads With previous technology, the ability to extract NG was limited to about 50% of the product that was found At a trunk line, measuring 6" to 12" in diameter, the gas slows down series of regulators reduce the pressure to anywhere from 100 to 1,000 psi as it moves to a gas plant for processing The final product, almost pure methane, moves to gas transmission lines that are buried at various depths in accordance with federal regulations In normal soil, depth ranges from 30" (Class 1 locations; less populated areas) to 36" (Class 2, 3, and 4 locations; more populated areas) Pipe installed in a navigable river,stream, or harbor must be installed with a minimum cover of 48” in soil or 24” in consolidated rock In consolidated rock, it ranges from 18" to 24 CHAPTER 4 TACTICAL AIR MONITORING Tactical considerations -pair your 4 gas monitor with an explosive gas meter that detects below 1% -know your lowest level of gas detection -depend on your meter, not your nose -you make like and death decisions based on how well you understand your air monitor -laser based gas detectors vastly increase our safety efficiency -lean alarm levels and action levels for your sop Introduction There are often no outward signs of danger at life threatening NGEs No odor, no plume, no dead or injured, no screaming civilians, no smoke and no flames Need to use and understand explosive and combustible gas indicators Read the directions Most important suggestion Us navy seals say there is no excellence without pain, it is painful to read directions but it is necessary Calibration 2nd most important for air monitoring equipment Must be calibrated in accordance with manufacturer directions Calibration is when you show the instrument a known concentration of gas and tell it to adjust its measurements to the known concentration or number Bump testing is when the meter is shown a known concentration and reacts properly to it, usually by sounding the alarm and providing the correct reading Sensory for size up 5 main types of gas detection in common use by FD Laser Wheatstone Metal oxide sensor Catalytic bead Electrochemical Laser Gas Sensors Newest and the best sensor for NG Rage of 100’ and can detect gas in 5-50,000 PPM Only require a gas plume for the laser to pass through and a surface for reflecting the laser back to the instrument The instrument analyzes the difference in energy sent out from wha this reflected back and provides us with an immediate digital display 2 PPM-M is the typical background level of methane in air Response time of 0.10 sec Also has an audible warning when the reflection of the laser is not adequate to provide a reliable reading Internal battery has a 6 hour life cycle Laser deterctors vastly accelerate your size up. One FF can almost instantly size up important areas where gas may be leaking or present Locked buildings Often the utility will ask ff to force their way into a building that contains or may contain levels of gas. There is no safe way to do this Laser based remote methane detector can reveal methane through glass Ability to remotely determine the presence or absence of gas during the initial size up Heavily tinted windows as well as some energy efficient glass may also limit the effectiveness of laser Laser detector limitations They will not provide the concentration of vapors present, to determine levels in percent LEL responders must still follow up with a CGI BRIGHT LIGHT: green spotter laser will show you the area attempting to detect gas Hard to see in direct sunlight or brightly lit snowy areas Gases other than methane: the laser is specific to methane and simply will not sense any other flammable gas or flammable liquid vapors REFLECTIVE WINDOWS- tinted or mirrored windows that reflect the laser impede its use. SHADES,BLINDS, DRAPES: these will prevent the laser from penetrating deep into the building from the outside Advantages of a laser detector Speed Critical information Distance Locked buildings Training Versatility Flooded buildings WHEATSTONE BRIDGE Older technology that works on the same basic principles as most CGI Gas is pumped in and moves across a heated coil that causes the gas to burn The difference in electrical resistance is shown to us as an LEL reading A platinum wire is used because it will cause the gas to burn at less than flammable concentrations ( electrical circuit detects changes in resistance by comparing the heating of one coil, which can oxidize the gas, to a second coil, which does not react with gas) METAL OXIDE SENSOR Strength is the ability to detect very low levels of combustible gases almost instantly Pair with or built into your air monitor Gases react with thin piece of metal oxide in a chemical undergoing an oxidation or reduction reaction Displays as digital display or a relative concentration with audible tick sounds like a Geiger counter, more ticks means more gas Advantage of MOS is the instant ability to detect and provide data and the ability to detect at much lower levels than a catalytic bead or Wheatstone bridge A common hazmat method is to use two types of technology to monitor for a target gas or unkown MOS picks up dust, dirt and other particulates; moisture in the air; flammable gasses; combustible gasses; or just about any chemical with enough vapor pressure to get it into the air Obvious negative is that it detects more than just flammable gases MOS offers a resolution of about 10 PPM, a detection level not availible with other technologies MOS will respond instantly to common spilled or leaking flammable to which we are called, including propane and gasoline MOS detects acetone, alcohol, ammonia, butane, ethylene oxide, gasoline, halon, hydrogen, industrial solvents, jet fuel, lacquer thinner, methane and some refrigerants It will tell you if something is there or not but like a PID , not what the instrument is sensing for you CATALYTIC BEAD SENSOR Mostly replaced the old Wheatstone bridge sensor Bowl shaped string of metal with a bead of metal in the middle coated with a catalytic material that helps burn the gas sample off efficiently. LEL Sensor Poisons Catalytic bead can be easily compromised RAE SYSTEMS TECHNICAL NOTE #144 explains Most errors poisons are silicon compounds, silanes, silicones, and silicates Lead compounds, such as tetraethyl lead in gasoline, reduces LEL sensitivity, especially for combustibles with high ignition temperatures like methane Catalytic bead sensors should be kept away from most household cleaning products, including leather and vinyl cleaners and conditioners we may use in or on the rigs Other items include seals, polishes, cosmetic or medicinal hand creams, valve and regulator lubricants, self stick labels ELECTROCHEMICAL SENSORS Usually included in our 4 gas meter and typically selected to sense carbon monoxide, oxygen and toxic gas ( often hydrogen sulfide) A selection of sensors covers carbon monoxide calls and elevated oxygen situations and is a good general choice for most FDs use based on OSHA confined space air monitoring regulations What is important and not known it the t90. Rae system technical Note #114 describes it as The time for a sensor to reach 90% of its final stable reading. Typically an exposure of twice the t90 time is required to get a stable reading. Response times of sensors and instruments may be different. The response time of an instrument is dependent on sensor response time and test conditions like calibration gas flow rate,temp, etc Often t90 times may be 15 seconds or more Manuals determine any cross sensitivities sensor my have Co cross sensors to hydrogen (given off by over charged lead acid batteries) Co sensors are also cross sensitive to acetylene CO is a byproduct of roasted coffee, with ground coffee producing higher amounts than whole bean Nitrogen was injected into the packaging to keep coffee fresh Workers shut down production but nitrogen continued to flow and displace O2 The oxygen sensor is likely the most important sensor in air monitor Less oxygen results in less efficient burning, giving a risk of false low reading for combustible gas Look at oxygen reading as well as your LEL reading 20.9% oxygen reading is low, means something else has taken the place of the oxygen molecules in the room 1% reduction in oxygen is 5X10,000 which means 50,000 PPM of something has taken the place of O2 Chlorine gas, IDLH is 10 PPM, same for hydrogen sulfide ACTION LEVELS No national standards for action levels for flammable and explosive gases When numerical reading on monitor reaches or exceeds a number specific to SOP Sets a guideline for the mandatory evacuation of the building or area CHAPTER 5 TACTICAL RESPONSE PROCEDURES 7 TYPES OF GAS EMERGENCIES 2 BASIC TYPES OF GAS EMERGENCIES: MAJOR AND MINOR Life safety first Primary mission of the FD is life safety. AEGIS , company which provides insurance for gas utilities calls it “find and fix syndrome” Life safety must always override “find and fix” Policies Overall fire ground strategies and tactics Should be clear, short, mission essential Short enough to recall but. Long enough to direct the overall mission Procedures Universally, procedures are very very weak Not based on industry best practices Utility perspective has one goal “find and fix the leak in order to get the customers back online FDs mission is life safety Pipeline and hazardous Material Safety Administration recommends 7 procedures be included in FD SOP Outside odor of gas Locked buildings Building explosion Excavation damage Inside odor of gas Leak with fire Transmission line emergencies Many SOPS contain useless information 4 things policies and procedures mean to us Must plan to be operations on your own for a max amount of time you expect it to take the technician to AOS Gas tech cannot be at your command post and running procedures to help mitigate the leak at the same time Unless you have given the tech a radio or assigned a ff to them, you have no communication with the tech We at the FD can do multiple tasks simultaneously because we have a crew SOPs should be framed around these concepts Life safety is the FDs mission and responsibility and no one else’s FD is in charge, all others are technical experts or advisors Size up is critical step in determining the life hazard Establish the kill box early and update it Different leaks need different procedures Air monitoring guidelines Action levels The hierarchy Sop should closely align with local utility procedures Reach out to utility, get their procedures and make sure FDs are based around theirs If not cooperative, they are public documents subject to freedom of information laws Kill box awareness Introduced by Jerry Knapp and Dan Moran in march 2017 Selected to delineate it from “hot zone” Defining a kill Bo’s is one of the most effective procedural steps you can institute to improve both civilian life. Safety and our safety at a NGE Arouca around the building where you will likely be killed if you are standing there if or when the contained gas explodes FDNY Chief killed, standing 75’ from building and operating about an hour after the call was received Like the collapse zone at fires and the hot zone at hazmat, we should stay out of the kill box at gas jobs Walls tend to be blown outward leaving “V” shaped void in the kill box off the corners of the home Kill box sets the crews approach to the call; assume the worst possible outcome until proven otherwise TRUST BUT VERIFY We are all responsible as firefighter for life safety, waiting for the utility tech to do our job for us is dereliction of duty “Do what the tech says” we are blindly give away out responsibility to out civilians and crew memebers by hoping the tech is correct, well trained, and aware of what to do CASE HISTORY 1 Teaneck NJ: Utility called out twice, 2 weeks before and on the day of explosion Unable to locate leak Claims utility never entered home to check for gas Always practice our policy of “life safety first” on scene CASE HISTORY 2 Kansas City FD reports to gas leak Followed lead of Missouri Gas worker and did not initiate evacuation of restaurant Hour after calls, restaurant exploded NTSB states emergency responders should ‘rapidly assess’ gas leaks to determine if prompt evacuations are warranted CASE 3 East Harlem, NY killed 8 in 2014 Consolidated Edison inc reached state record settlement of $153.3 million Caused by faulty connection between two gas pipes as well as a hole in nearby sewer line NY had known about damage for at least 8 years PLAN B You don’t have one Plan A must be designed to minimize the risks to your crew by taking reasonable and aggressive risks in the interest of life safety Complacency is every FF enemy, no plan B when assumption is wrong At best plan B is often the burn or trauma center, bunker gear not rated for explosions Wear gear, don’t expect protection Personnel should open sewer manholes but not electric manholes Pulling manhole cover is like venting, gives the gas a path of least resistance to escape Electric manholes should only be opened when utility personnel request it and the IC approves the request Underground electrical conduits can provide a rapid channel for gas migration into nearby buildings CO sensor is likely cross sensitive to natural gas and propane May show false CO reading when exposed to NG CO is flammable at high concentrations and may trick LEL sensor SIZE UP First step is to determine if there is a life hazard; is this a significant leak or a minor odor call RECOGNIZE GAS LEAKS BY SIGHT Marks out in the street Dead or dying vegetation Unusual changes to soil Dry, blowing dirt near gas line Bubbling water over a gas line Swarms of insects or piles of dead insects Bar holes 3/4” – 1” holes in pavement or soil punched by gas techs to determine if gas is migrating underground Procedures should be based around the types of buildings and NGEs to which you respond as opposed to a list of generalized dos and donts Urban GAS INSTALLATIONS Apartment buildings have multiple risers To emphasize the importance of distinguishing between minor and major leak conditions, repeated no less than 3 times in the 44 page document ( FDNY SOP ) Conditions indicative of a major gas emergency Serious damage to major components of gas infrastructure 10% LEL or greater detected outside or inside Elevated natural gas reading (20% LEL or greater) in an unvented, subsurface structure Gas present in two or more subsurface structures Indications of gas migrating into a building from an outside source Gas leaking inside of a structure and controlling valve can not be located or is inoperable Gas leaking or present inside of a wall or void in structure FDNY investigation sections states “ the first priority in an NGE is to ensure there is not a Major Gas Emergency, this is followed by locating and mitigating minor leaks” Ladder company inside team key direction; if any natural gas levels are displayed on NG meter upon entering the building, the inside team should proceed directly to the basement or cellar to evaluate conditions” Subsurface Leak Blast zone is the area to be evacuated, which should be entered only for life saving efforts. Use meters to determine how much ng has accumulated, estimate can be made as to the location and size of potential blast zone. Evacuate this area FDNY SOPs; 10% LEL in an outside or inside general atmosphere. 20% LEL or greater in an unvented subsurface structure; key action levels Major leaks inside buildings where the leak has been found and controlled, memebers are allowed to continue to operate up to 80% LEL If the leak is not found, 10% LEL or above defines the potential blast zone OPERATIONS INSIDE THE BLAST ZONE Quick evacuation of likely occupants Minimum exposure to members Min time spent in the potential blast zone to obtain the first objective Rapid evacuation is different than primary searches at fires and it should be executed with a few members as possible while covering the greatest area in the shortest available time Forcible entry should only be accomplished for a known life hazard and should not be attempted to access areas that show no signs of being occupied Use hydraulic ram not irons Critical to SOP is that it includes Response policies and a clear mission statement: life safety General guidelines with enough latitude for on scene officers to use their judgment Specific strategies and tactics to guide on scene decisions and actions Action levels to ensure safety of civilians and members Clear command and control methods of decision points Enough information to provide solid understanding and guidance to all responders Chapter 6 Outside odor of gas Critical Tactical Consideration 1. size up using standard threat analysis methods 2. conduct simultaneous operations to provide life safety 3. make a kill box estimation and adjustments 4. consider underground migration of natural gas 5. hav an air monitoring plan including subsurface structures 6. keep appraised of conditions that may affect the life hazard 7. know your tactical options Size up need to have several tracks (higher or lower life safety concerns, different gas leak sources, etc.) and possible strategy and tactical solutions or outcomes for the situation This methodology is in part based on the standard process for a threat analysis You always consider at least the most likely scenario and the most dangerous. In the case of an NGE, there may be several options between these extremes purpose is to steer you in collecting facts or clues, helping make your size-up more effective A good IC will keep at least two tracks open One that says that this is water and obviously not a threat Second says this is the most toxic chemical known just because you find a leak does not mean you are finished. Your air monitoring for life safety must be thorough and eliminate all possible or suspected sources of escaping gas Montagna recommends that since firefighters will often be on the scene before the technician, fire Fighters should become knowledgeable about the potential hazards and safety measures needed and the appropriate actions to take. One fire fighter can monitor the half foot dial on the meter to determine if gas is passing through; if required, that Fire Fighter can shut off the gas at the meter to a building, thereby minimizing ignition sources and possibly stopping the leak SCENARIO: OUTSIDE ODOR OF GAS Where did you park your rigs? Practically, parking on the main street and walking into the cul-de-sac seems like the right approach. Avoid parking near all subsurface structures—such as electric vaults, manholes, and storm and sanitary sewers— since they may contain explosive levels of accumulated gas Clues from dispatch information would heighten concern The call was reported as an outside odor that may have its source from an underground main or service line. If this is the case, soil could scrub out the odorant and NG could migrate largely undetected into nearby structures, causing a high life hazard that will take you some time to assess The Emergency Response Guidebook (ERG) recommends a 330' isolation as an immediate precautionary measure for compressed gases Large scale evacuation would take considerable time and manpower The fact that the utility was called last night and did not find any leaks should raise both your general suspicion and your life safety concern. This fact takes you a bit further down the dangerous call track. You should minimize the life hazard to your crew by only taking one firefighter and your air monitor with you to investigate Based on the dispatch information and what you find on arrival, what do you think the possible source(s) of the leak may be? An outside odor of gas could be coming from a leak in either a meter installation outside the house or an underground main or service line What is your plan for air monitoring? Air monitors will be started in and calibrated for fresh air. Suspecting this is an underground leak where a serious life hazard (migration of gas into nearby buildings) is possible, you begin your monitoring as you and your firefighter walk to meet the caller You quickly monitor the nearest subsurface structures on the walk toward House #1. You get a zero reading from the one storm sewer and one sanitary manhole on your walking path to House #1 you checked to be sure there was not a water infiltration cover under the perforated cast iron manhole cover at street level some municipalities place a second cover under the heavy cast iron cover to keep out rain water, which will prevent fugitive natural gas from rising up through perforations in the road surface level cover and result in zero readings when there is gas below it Monitoring a subsurface structure with a 4-gas meter. Note that the VreVghter is not positioned over the cover in case it were to be launched into the air by igniting gas within the subsurface structure. The firefighter has already checked to be sure there is not a second water infiltration prevention cover under the street cover by either pulling up the cover or putting a probe (stick or long screwdriver) into the perforation. This It is a good sign that there is no underground migration of gas into subsurface structures—at least at your first monitoring point.The only thing this monitoring deVnitively tells you is that gas is not venting from this manhole If you are using a 4-gas monitor, remember that your lowest detection level is 1% lower explosive limit (LEL) or 500 ppm Plan to make face to face contact with the caller It is important to ask her what she smelled, where, and when Thermal inversions in the atmosphere can slow and even prevent gas from rising and dissipating When you ask the occupant when and where she smelled gas, she tells you she smelled the odor near the gas meter on the side of her house The metal oxide explosive gas detector finds a leak on a fitting in the meter outside the house It is a small leak that does not register on the 4-gas, but the metal oxide sensor is able to detect it Brian Focht reminds us that from his experience, an indoor call for gas can take you outside, and an outside call can take you inside How do you get info from utility about last night’s call and incoming utility resources Ask your dispatcher to call the utility dispatcher and relay this information to you What is your estimation of the kill box at this point? Finding the leak can drastically reduce the kill box area Here is a valuable reminder for damaged gas pipes that is in VreVghter lingo: “If it is broken and leaking on the outside, it may be broken and leaking on the inside.” We need to check. What were your initial actions to achieve life safety and your actions for life safety as your size-up matured Another action you may take is to monitor air inside other nearby homes to be sure your size-up theory is correct, further increasing your life safety factor If you are using your 4-gas with an LEL sensor, its lower level of detection may be as high as 500 ppm Your instruments may not be able to detect lower levels in manholes or even small leaks from meter piping Use of an explosive gas detector with low detection capability is crucial to your success metal oxide detector (see chapter 4) is appropriate here, especially paired with a 4-gas monitor with a catalytic bead sensor The laser based detector will tell you where there is a little gas, a lot of gas, or no gas It will give you this information instantly, which is a huge advantage over other gas monitors. However, you need to follow up and measure levels of gas and locations of possible leaks, and your 4-gas is the best choice to do this. Size-up and air monitoring subsurface structures showed it had not migrated into those subsurface structures, but there might have been underground gas migration, which the utility can discover and vent SCENARIO: OUTSIDE ODOR OF GAS WITH UNDERGROUND MIGRATION The odor is near House #1 and a storm drain. Your local gas company was at House #3 last night on an odor complaint but did not Vnd any evidence of leaking NG Where did you park your rigs? This scenario assumes there is an underground leak from a gas distribution main. Gas can and will migrate underground using the path of the least resistance You should park your rigs on the main street, outside your Vrst estimate of the kill box. This spot should help protect your crew’s life safety; furthermore, it will be a good place for a command post if the situation escalates. Common utility trenches are found in newer subdivisions and new construction with underground utilities, including electric and communications NG can enter electric or communication line conduits and sewer pipes before Vnally escaping into buildings NG can escape from a main into a subsurface structure, where it can enter buildings through sanitary and storm drainage pipes, foundations cracks, or soil. In urban situations, NG can also enter buildings via utility chases and conduits. Initial Kill box it is important to make a good estimate of the kill box to protect your Vrst-due unit, your command post, and the lives of civilians. Your train of thought is that this is an underground leak that is migrating. Like a search at a house fire, always consider there is a life hazard until you prove otherwise. What clues from dispatch information would heighten your concern Obviously, NG migrating into occupied structures that contain numerous ignition sources is a high life hazard life safety of the occupants is your highest priority NG in a low-pressure system poses a risk of silently engulfing you. Low pressure usually worries gas mechanics more than elevated pressure, because it eliminates telltale danger signs such as noise or dancing soil. If the system is a 60–90 psi main system, there is a lot of energy available to help NG move quickly and undetected through the ground and into nearby buildings. Based on the dispatch information and what you Vnd on arrival, what do you think the possible source(s) of the leak may be? In this case, the caller reported a strong odor near the curb and in a storm drain, which points you toward a main or service line. Both will be at distribution pressure, which is 60–90 psi (conversely, the pressure regulator on the meter is where it is reduced for in-house use, usually to about ¼ psi) Look around for bar hole penetrations in the pavement or marks that show where underground utilities are. If marks are present, it may indicate that utility will soon make a repair A bar hole tool punches a small hole in soil or asphalt to detect underground gas. Note that the operator has electrical insulating gloves and dielectric boots in case he should hit an underground electric line that may be buried in a common trench. What is your plan for air monitoring If you suspect a migrating underground leak, the priority is life safety You need to Vnd out where it is migrating to (nearby buildings), how much (meter readings from inside these buildings), and how far (how many buildings on each side of the leak has it gone to) Start your air monitoring investigations at the buildings closest to the leak start with those in the most danger fist (those closest to the reported leak site) and work your way out While walking toward the reported odor site, you take a quick check of subsurface structures to determine whether the gas is migrating or not The Vrst storm drain you monitor shows a gas level of 50% LEL: your Vrst clue that you have an active and possibly aggressive underground leak move directly to House #1, where the odor was reported As you enter the living room, your meter registers 10% LEL just inside the front door accepted level for mandatory evacuation is 10% LEL The sanitary sewer in the street shows an 80% LEL reading as you move from House #1 to House #2, conVrming the underground leak is migrating You direct him to get himself and his family out to the Vre engine at the corner, taking care not to turn on or off any light switches. As he is exiting, you get a 10% LEL reading just inside the front door. Proceeding to the surrounding structures, you should air monitor to determine the kill box and use evacuation or protection in place to achieve life safety. What is your estimation of the kill box at this point We have removed the life hazard from Houses #1 and #2, because we know there is gas in these houses and the action level for mandatory evacuation in our notional SOP is 10% LEL. The radius of the kill box now extends at least 100' from those houses. This is a success so far To achieve incident stabilization, the FD should work in tandem with utility The FD can shut off the gas at the meters for the homes (thereby removing ignition sources for pilot lights). The utility can shut off the leaking gas main at an underground valve, shut off electric remotely, repair the main, and determine it is safe for occupants to return Continuous air monitoring of the homes in the area is required to ensure migrating gas is not accumulating What were your initial actions to achieve life safety Recognizing the threat of an underground gas leak to surrounding structures is the Vrst key step Steps toward achieving the life safety benchmark include the following: recognizing a threat, swiftly sending VreVghters to the closest building to the suspected leak origin, conducting air monitoring, interviewing occupants to learn if they smell gas, and moving occupants to a safe location if the action level in your SOP is exceeded or if good Vreground common sense or gut feelings dictates. Once again, make sure you start with those in the most danger Vrst—those closest to the source of the underground leak. Working with the utility technician during the life safety phase and the incident stabilization phase is important. The technician can provide expert advice and help with monitoring the air—though again, trust but verify Other considerations Paving: Pavement can have a tremendous effect on how far and in what concentration the gas can accumulate in buildings. Continuous paving on the street and then onto the sidewalk can prevent the NG from escaping upward. In this case, the path of the least resistance may be into the building via the routes discussed previously. Frost: A frost layer in the ground can act as a cap, much like the asphalt and concrete in an urban situation Frost trapped massive amounts of gas from an underground leak. Contained gas continued to burn for hours after the initial explosion and Vre. The utility used a Venturi system—blowing compressed air across a venture attached to a pipe driven into the ground—in an attempt to remove gas that had saturated the soil Soil density: Soils vary widely across the nation, but they can vary locally too, especially in built-up locations where large areas have been filled. Loosely packed soil will allow gas to migrate more easily than hard-packed clay-type soils Underground utilities: As we noted previously, underground utilities provide numerous routes of entry for migrating gas. If trenches are backfilled with loose material, they can provide a highway for migrating gas. Time: Obviously, the longer the gas continues to leak, the more volume and ignition opportunities become available to cause problems Damage: Damage may result in multiple escape points. For example, if a back hoe pulls a gas service line, the pipes may be damaged inside the house, creating another escape point in addition to the obvious one in the excavation. Again, a blinding flash of the obvious, more escape points mean more gas and more possible trouble for us. Gas pressure: Generally, leaks from higher pressure gas lines can drive gas faster and in greater volume than from lower pressure lines. Masked odor: Odorant may be masked by other odors in the building, such as fumes from painting or polyurethane from floors, cleaning liquids, gasoline, propane, cooking, and commercial or industrial processes Vegetation: Dead vegetation can be the sign of a long-standing gas leak Dead grass over leaking gas. Dead or dying trees and shrubs are a good indicator as well Cleanliness of subsurface structures: Mold and insects within subsurface structures can be a sign gas has been present for some time Bubbles: Puddles or running water at sites where gas is escaping from the soil or pavement may indicate a leak by the presence of bubbles A dry floor drain in a basement can be a source of odors and a pathway for leaking gas to enter a building A makeshift bar hole device for soil can be the spoon end of your hook his provides an opening in the soil or sod to release migrating gas It is important to remember that water running through manholes or sanitary and storm lines creates an air current that can drag or push gas significant distances An underground gas leak can be one of the most challenging types of NGEs to mitigate CHAPTER 7 LOCKED BUILDINGS Locked buildings are very dangerous in natural gas emergency Collect all the facts you need for a reasonable procedure Fire ground decision points and procedures you put in place at any NGE, are yours and yours alone May necessitate a switch from very aggressive tactics to more passive ones Things to consider in a locked building How much gas is in there Is it in the explosive or flammable range Is it increasing or decreasing, and will it be in the explosive range soon How long will that take Is it above the explosive or flammable range When will an ignition source like a thermostat, phone, or electronic igniter for a water heater or boiler kick on with a spark, triggering an explosion Urban or suburban Suburban with single family homes, you may be able to control the life hazard by evacuating kill box and a few nearby houses allowing self vent Urban with appartment, best way to minimize life hazard may be immediate action Choosing immediate action may be supported in urban situations Risking FF is an excellent option when you need to save nearby lives that cannot be protected any other way Underlying factor is how much life hazard do we have Think first, then act Consider 4 critical strategic factors that will help you decide how much to risk at this call We have yet to hear about anyone being asphyxiated from NG exposure. People smell NG It is impossible to safely monitor the gas concentrations inside the building. Look for unlocked windows and slide them open to use monitor equipment Some utilities state that any measured amount of gas outside the building is enough cause for remotely shutting off electric gas service to locked buildings There are numerous ignition sources inside the building SCENARIO You and your Vrst-due units are dispatched to an outside odor of gas near House #1 in the following image (Vg. 7–3). It is 27°F, February 22, Presidents’ Day, a federal holiday. Dispatch time is 1213 hours. For training purposes, the odor area is indicated by a cloud Where do you park your rigs? Upon arrival to the scene, you park about 100' from the reported address in accordance with your SOP. There is a strong odor of gas when you leave the rig, so you back up another 100' and ask the police department (PD) to set up traffic control points (TCPs) as a perimeter You start your air monitoring as you get out of your rig. The FDNY’s newly revised SOP uses 10% LEL in outside air as a measurement threshold or action level, one which potentially indicates a major NGE and requires a shift in procedures One civilian reports that a contractor hit a gas main under the middle of the road with a boring device The civilian tells you NG has been leaking for about 30 minutes. What is your initial estimation of the kill box and life safety at this point? You look at the hole or trench where the contractor inserted the boring device and see gas escaping through the dancing soil. Our training tells us that NG is lighter than air, so life safety does not seem to be a problem because the gas is dissipating, This, however, is not true The key point here is that some, not all of the gas is exiting the trench and harmlessly dissipating A large volume of gas is trapped underground, and this confinement is made worse by the frost layer in the ground causing the gas to take the path of the least resistance The inner circle should be 75' from the front door of the locked building The outer circle is about 150' from the front door of the gas- containing building The Emergency Response Guidebook recommends a 330' immediate evacuation zone for flammable You don’t know if gas has entered nearby buildings. It will take air monitoring in each of the buildings until you get zero readings to determine the extent of the underground plume and how much danger if presents to these structures. Life safety is our primary mission, so whatever size your kill box is, you must start evacuating from the closest buildings to the leak first Start near the leak and work your way away from it As you get civilians out of the immediate danger zone, it buys you some time to get air monitoring readings in buildings away from the immediate leak area. What clues from dispatch information heighten your life hazard concern? It was dispatched as an outside odor. Worst case, it could be an underground leak; best case, a minor outdoor leak What are your immediate actions to meet our mission of life safety? Work from the houses in the most danger toward those in the least danger, evacuating from the inside to the outside of the kill box a quick stop at subsurface structures such as sanitary and storm drains will provide the incident