Hazmat Chapter 12: Implementing Response Objectives
What is a confined space?
"any area that has limited or restricted means for entry or exit; is large enough and so configured that an employee can bodily enter and perform assigned work; and is not designed for continuous employee occupancy."
Mayday definition
"any situation at a hazmat/WMD incident where an entry team member is unable to safely exit the hot zone or an event [i.e., safety problem] cannot be resolved by the entry team member within 30 seconds."
LNG presents emergency responders with three main tactical problems:
(1) fire, (2) vapor cloud release, or (3) cryogenic spill.
To determine which strategy and tactics are best suited to change the outcome of a particular hazmat incident, responders must be able to understand 3 things.
1) what has already happened, (2) what is happening now, and (3) what will likely happen in the future. • This evaluation process is the cornerstone of risk-based decision making at hazmat/WMD incidents.
The IC and ICS supervisors should ensure these questions have been evaluated and answered before committing personnel to rescue in a confined space:
1. Can emergency responders safely enter the confined space? (Confined spaces may be flammable, toxic, oxygen deficient/enriched) 2. Are you rescuing someone or recovering a body? (The atmosphere is almost always toxic before reaching the flammable concentration) 3. Do you have control of the situation and is there a coordinated incident action plan?
Factors that responders must consider before approving a lifting or uprighting operation include the following:
1. Conduct a damage assessment of the container before moving or lifting the tank. 2. Qualified and experienced rigging specialists and crane operators must be available to supervise and perform the uprighting or lifting operation.
Foam concentrate requirements can be determined by the following process:
1. Determine the type of fuel involved. 2. Determine the surface area involved. 3. Determine the recommended rate (Foam application = area x recommended application rate). 4. Determine the duration of foam application (Required foam solution = foam application x duration). 5. Determine the quantity of foam concentrate required. ( Required amount foam concentrate = required foam solution x 3%).
3 main methods for liquid product transfers of liquified gases and cryogenics.
1. Equalize pressure and pump the liquid. 2. Product displacement with compressors (removes vapors from receiving tank causing pressure differential). 3. Pressure displacement (inert gasses used as positive pressure).
LNG presents two main hazards and risks:
1. Flammability 2. Liquid or vapor dispersion
Steps for Controlling a leak in a Hazmat cylinder:
1. Fusible plug 2. Fusible plug threads 3. Valve stem or assembly blow-out 4. Valve seat 5. Valve packing 6. Valve inlet threads 7. Cylinder side wall damage (First, shift the leak into an upright position to keep in the gas phase of the product. Sound the side walls of the container to detect additional container damage. Then, use a sidewall patch kit with a compatible patch to secure the leak.
What are the 3 main methods for liquid product transfer?
1. Gravity flow 2. Pump transfers 3. Pressure transfers
Grounding and bounding sequence for an overturned cargo tank truck
1. Ground damaged vehicle first. 2. Bond damaged to recovery 3. Ground recovery at anytime
Grounding and bonding sequence of an upright vehicle
1. Ground damaged vehicle first. 2. Ground recovery vehicle. 3. Bond from damaged to recovery.
What are the "Golden Rules of Transfers"?
1. If product is being removed from a container, the loss must be replaced by an equal volume of air at a similar rate of flow. Translation: If you take something out of a container, you must put something else back in. 2. If a product is placed in a container, the container must displace an equal amount of air/vapor at a similar rate of flow. Translation: If you put something in a container, you must take something else out. 3. Failure to abide by both of these rules may result in a catastrophic failure of the container.
The following activities can help maintain site discipline until the problem is eliminated and the incident safely terminated:
1. Maintain an incident safety officer throughout the incident. 2. Use formal site safety checklists. 3. Enforce isolation perimeter security and the use of hazard control zones. 4. Establish a crew rotation schedule.
LNG fires are presented in 3 scenarios.
1. Pool fire 2. Jet fire 3. Vapor cloud fire
The tactical priorities for managing a flammable gas fire are as follows:
1. Protect primary and secondary exposures to the fire. 2. Isolate the flammable gas source feeding the fire. 3. Reduce the operating pressure of the line feeding the fire. 4. Let the fire self-extinguish and consume residual flammable gas in the vessel or piping system. 5. Control and extinguish secondary fires.
Static electricity is an accumulated electrical charge. For static electricity to act as an ignition source, the following four conditions must be fulfilled:
1. There must be static generation. 2. Must be enough static build up. 3. Must have a spark big enough. 4. Must have a flammable mixture.
To complete a site safety and control plan, follow these steps:
1. Understand the nature of the problem. 2. Identify your available and potential resources 3. Develop incident objectives. 4. Develop tactics 5. Identify an operational period 6. Identify the players 7. Identify emergency procedures 8. Conduct the briefing
Before initiating containment operations, emergency responders should consider the following questions:
1. What are the hazmats involved? 2. What is the physical form? 3. What are the hazards? 4. What are the risks to people? 5. What are the abilities of the entry team? 6. Are special tools and equipment needed for the operation? 7. Are responders ready to perform emergency care and Decon?
Before selecting and implementing a response action, the following questions must be asked and answered for every potential hazmat FIRE scenario:
1. What materials are involved? 2. What are its hazards? 3. What type of container is involved? 4. What are the risk to people? 5. Is any special resources needed? 6. What happens if you do nothing?
There are four important criteria that must be met before dilution is attempted.
1. is not water reactive, 2. will not generate a toxic gas on contact with water, 3. will not form any kind of solid or precipitate, and 4. is totally water soluble.
What is vapor suppression?
A physical method of confinement to reduce or eliminate the vapors emanating from a spilled or released material. Operationally, it is an offensive technique used to mitigate the evolution of flammable, corrosive, or toxic vapors and reduce the surface area exposed to the atmosphere. Examples include the use of Class B firefighting foams and chemical vapor suppressants (Ansul's TARGET-7)
What is Vapor Dispersion?
A physical method of confinement. Water spray or fans are used to disperse or move vapors away from the surface areas of the product. Vapor dispersion is particularly effective on water-soluble materials (i.e., anhydrous ammonia)
What is Pressure Isolation and Reduction?
A physical or chemical method of containment by which the internal pressure of a closed container is reduced. The tactical objective is to decrease the internal pressure enough to reduce the flow or minimize the potential of a container failure.
What does a well-defined tactic have?
A stated objective that can be achieved using specific procedures and tasks in a reasonable amount of time. ( i.e. Attack and extinguish the gasoline spill fire involving 55 gal drums using AFFF concentrate supplied by two handlines within 20 minutes.)
If an adequate water and foam supply is not available for protecting exposures and controlling the fire, the IC should consider using defensive or nonintervention tactics until enough resources are available.
As a tactical guideline, do not start foam application operations until enough foam concentrate is onsite to extinguish 100% of the exposed flammable liquid surface area.
When should exposure lines be in place?
Exposure lines should be applied when there is direct flame impingement on exposed tanks and/or when there is enough radiated heat to cause steam at the tank shell when water is applied.
Recognize that almost all confinement tactics are what?
First aid measures and usually fail over time.
What is the most common and dangerous hazard class to emergency responders?
Flammable liquid storage tank fires. No other class of hazmat or type of container has killed more firefighter.
When is Flaring used most often?
Flaring is usually used in the propane industry to safely burn off product in cylinders, trucks, and rail cars when they have been severely damaged or when access to the accident site is impractical for offloading to another vehicle.
When building a diversion barrier, consider the angle and speed of the oncoming spill.
For fast-moving spills, barriers built at a 45° perpendicular angle will be ineffective. Use a barrier angle of 60° or more for fast-moving spills.
When dealing with liquefied gases (i.e., chlorine, anhydrous ammonia, LPG), rotate nonbulk containers to deal with a vapor release rather than a liquid release.
If liquid escapes, it will expand the problem and hazard area (i.e., liquid/vapor expansion ratio for chlorine is 460 to 1 and 850 to 1 for ammonia).
What does NFPA 77 recommend for grounding?
If the purpose of the temporary grounding system is to dissipate static electricity, a total resistance of up to 1 kohm (1000 ohms) in the ground path to earth is considered adequate.
In an IDLH environment, All lighting and radio equipment must be set to what standard?
National Electric Code (NEC) Class 1, Division 2 locations.
What should you never do with a pressure-fed flammable gas fire?
Never extinguish the fire unless you can control the fuel supply. Isolate the source of the gas and let the fire self-extinguish. This way, it will consume any residual gas in the vessel or piping system. Unignited flammable gases and vapors escaping under pressure rapidly form an unconfined vapor cloud. Ignition sources in the area often reignite the vapor cloud.
What must the IC so when there is a potential for a BLEVE?
Recognize it early and take immediate action to activate fixed water spray systems, monitor nozzles, provide cooling streams, and evacuate the area.
What is confinement?
Refers to the tactics or actions taken to confine or control a product release to a limited area. Defensive in nature.
What is Containment?
Refers to the tactics or actions taken to contain or keep a material in its container. As an offensive operation, containment tactics require personnel to enter the hot zone to control the release at its source.
Nonintervention tactics for reactive materials
Responders withdraw to a safe distance and allow the incident to run its natural course. A fire in a vehicle or structure that contains oxidizers, organic peroxides, or titanium metal powder—and is located in a remote area- is a classic example of a nonintervention scenario.
Before making decisions on spill control operations, you should review what?
Review the potential harmful effects that the leaking material will have on personnel downwind of the spill, where most of spill-control operations normally take place.
What is the ICS 208 form?
Site Safety and Control Plan-is a useful guide and template for an IC to structure mitigation efforts.
Product removal operations are usually performed by product and container specialists or environmental contractors.
Sometimes, public safety responders remain responsible for site safety and oversee all product transfer and removal operations until the incident is terminated.
Unlike flammable liquids and gases that leave responders with many options, the tactical options for reactive materials will often be limited unless the fire or reaction can be handled in its initial stages.
Tactical options for reactive materials include nonintervention, defensive tactics, and offensive tactics.
Predication and prevention is the essence of the risk evaluation process. In short, the operational strategy for the incident is developed based on:
The IC's evaluation of the current conditions and forecast of future conditions. Predictable is preventable.
The decision to use confinement tactics is based on what?
The availability of time, personnel, equipment, and supplies.
The challenge is to keep ahead of what the hazmat conditions will be when the entry team is ready to go to work.
The length of time needed to implement tactical objectives at the task level must be weighed against the window of opportunity available to implement the tactics.
Defensive tactics for flammable liquid emergencies
The main concerns during defensive operations are direct flame impingement and radiant heat exposures. Flame impingements must be cooled immediately(primary exposures), whereas radiant heat exposures (secondary exposures) should be handled as soon as possible. • Water streams should cool all areas above the liquid level.
polyfluoroalkyl substances (PFAS) Although effective for fire protection, their use is complicated by the environmental impacts associated with PFAS.
The newest generation of foam concentrates, used today, are synthetic fluorine-free foam concentrates (SFFF or F3).
What is grounding?
The process of connecting one or more conductive objects to the ground through an earthing electrode. Done to minimize potential differences between objects and the ground.
What is bonding?
The process of connecting two or more conductive objects together by means of a conductor. done to minimize potential differences between conductive objects, thereby minimizing or eliminating the chance of static sparking.
There are several tactical options available to achieve Confinement (spill control) strategies.
These include physical and chemical methods. • Absorption • Adsorption • Covering • Damming • Diking • Dilution • Diversion • Dispersion • Retention • Vapor Dispersion • Vapor Suppression
Nonintervention tactics are best used for flammable liquid emergencies when?
This option is sometimes used when there are not enough water supplies, little product can be saved, or there are no exposures in the immediate area.
MC 306/DOT 406 has a MAWP of 4 psig. These tank trucks will melt at temperatures as low as 1200°F when impinged by fire at the vapor space.
Upright gasoline tank truck fires often become open tank or "pit" fires after the top of the aluminum tank melts down to the liquid product level.
What is Retention?
a physical method of confinement by which a liquid is temporarily contained in an area where it can be absorbed, neutralized, or picked up for proper disposal. Retention tactics are meant to be more permanent.
What is Diversion?
a physical method of confinement where barriers are built on ground or placed in a waterway to intentionally steer the flow of a hazmat to an area where it will pose less harm to the community and the environment.
What is a boil-over?
a violent ejection of flammable liquid, specifically crude oil, from a container caused by the vaporization of water beneath the body of liquid.
Product removal operations cannot commence until after the incident site is stabilized. Stabilization means:
all fires have been extinguished, ignition sources have been controlled, and all spills and leaks have been controlled, as needed.
In nonfire situations where a cargo tank has been stressed and/or breached, tactical response objectives should focus on:
controlling all ignition sources and confining the spill/release to a limited area.
When are Offensive tactics for flammable gas emergencies implemented?
implemented when enough cooling water and related resources are available for a continuous, uninterrupted fire attack.
The majority of spill and leak situations encountered on nonpressure intermodal tank containers (T Codes 1 to 22 (IM 101 and 102 and IMO Type 1 and IMO Type 2) involve?
loading and unloading accidents.
Properties of LNG
methane in its liquid state. LNG is a flammable and odorless gas. Asphyxiant. It is a cryogenic liquid when stored and transported.
Without an oxygen supply to the brain, clinical death occurs in:
minutes, and biological death occurs in 5 minutes. Exposure to hazardous atmospheres accelerates the timeline.
The flammable gases most encountered by responders are:
natural gas (i.e., methane, or CH4) and the liquefied petroleum gases (propane and butane).
Tactical options for flammable liquid emergencies include:
nonintervention, defensive tactics, and offensive tactics.
Defensive tactics for flammable gas emergencies
protecting exposures and allowing the fire to burn. This tactic may include implementing a controlled burn of any remaining gas or flaring off the product.
A bulk storage tanks dike is required to be how large?
require the dike's capacity to be more than the amount of liquid that can be released from the largest tank in the diked area.
The primary sources of leaks on intermodal portable tank containers come from:
the foot valve, found at the bottom of the tank and from the manhole cover on top of the tank.
Criteria for evaluating and selecting operational modes include?
the level of available resources (i.e., personnel and equipment), the capabilities of emergency responders, and the potential harm created by the hazmat release.
What should Firefighting foam concentrates selection be based on?
the type of fuel (i.e., hydrocarbon vs. polar solvent), and the type and nature of the hazard to be protected (ie., spill scenario vs. storage tank).
What is the primary fire protection strategy at bulk LPG storage facilities?
to rapidly stop the flow of gas to the surrounding atmosphere and control potential ignition sources.
As a guideline, when should water streams applied to exposures in a diked area (i.e., adjoining storage tank) be temporarily shut down?
when they no longer produce steam at the point where water contacts the hot steel surface.
The response options that are available to change the outcome of an incident are based on what?
where you are on the risk timeline when you arrive at the scene.
What is a Strategy?
• "the general course of action, direction, or plan to accomplish incident objectives" • It is implemented through tactics, the specific actions taken to achieve a set of goals in line with the strategy. • designed to be broad, proactive, and achieve response objectives as safely as possible.
What are tactics?
• "the specific actions or tasks the IC uses to achieve strategies." • need to be concise, easy to communicate, and achievable in a given time frame with available resources.
What is Dilution?
• A chemical method by which a water-soluble solution, usually a corrosive, is diluted by adding large volumes of water to the spill. • dilution tactics are a last resort. • Dilution can be effective for small corrosive spills of 1 quart or less, especially for concentrated corrosives with a pH of 0-2 or 12-14.
What is Neutralization?
• A chemical method of containment by which a hazmat is neutralized by applying a second material to the original spill that will chemically react with it to form a less harmful substance. • during the initial phases of combining an acid and a base, a tremendous amount of energy may be generated, as well as toxic and flammable vapors. • limit neutralization operations to spills of less than 55 gal.
What is Solidification?
• A chemical method of containment whereby a liquid substance is chemically treated to create a solid material. • Often used for both corrosive and hydrocarbon spills. • The spilled hydrocarbon is adsorbed to granules to form a solid, nonflowing mixture.
Tactics for potential BLEVEs
• A nonintervention strategy is often the best option if the tank is on fire when you arrive at the scene. • Before using a defensive or offensive strategy, the IC must be satisfied that there is an adequate water supply to support the fire attack, the risks must have been evaluated enough, and the IC and the responders must have been properly trained in handling LPG fires. • Tank exposures to high-velocity jet flame (i.e., pressure-fed fire) need 500 gpm of water at the point of impingement. Exposures to radiant heat need 0.1 to 0.25 gpm/ft^2 to maintain the integrity of the exposure.
What is Diking?
• A physical method of confinement by which barriers are built across ground to control the movement of liquids, sludge, solids, or other materials. • Dikes are most effective when they can be built quickly. • Slow-moving or heavy materials should be confined in a circular-shaped dike. Faster moving products need a V-shaped dike constructed in the best available low-lying area.
What is Damming?
• A physical method of confinement by which barriers are built to prevent or reduce the quantity of liquid flowing into the environment.
What is covering?
• A physical method of confinement. It is typically a temporary measure. • Examples include: - Placing a plastic cover or tarp over a spill of dust or powder. - Placing a cover or barrier over a radioactive source, normally (alpha or beta) to reduce the amount of radiation being emitted.
What is Vacuuming?
• A physical method of containment by which a hazardous material is placed in a chemically compatible container simply by vacuuming it up. • commonly used for hydrocarbon liquids, solid particulates, asbestos fibers, and liquid mercury. • Uses a HEPA filter, which removes 99.7% of all particles > 0.3 microns.
What is overpacking? And methods to accomplish it?
• A physical method of containment by which a leaking drum, container, or cylinder is placed in a larger undamaged and compatible overpack container. • Inverted method of overpacking • Slide-in method of overpacking • V-roll (rolling slide-in) method of overpacking
What is Patching? And considerations for it?
• A physical method of containment involves placing a material or device over a breach to keep the hazmat in the container. • Select a patching device at least half a size larger than the breach. • Ensure the patch is compatible with the hazmat involved. • Container pressure is an important factor in evaluating the application and use of patching tactics.
What is Vent and burn?
• A process during which shaped explosive charges are placed by explosives demolition specialists on a flammable container to cut one or more holes in it. • The holes allow the contents of the container to flow into a containment area constructed adjacent to the breached car, where the product can safely burn off. • Two holes are needed: - Hole #1 is created at the high end of the tank car to reduce pressure. - Hole #2 is created at the low point to drain the product into the containment area for burning.
pay attention to the following site safety procedures for nonfire situations of a leaking cargo tank truck:
• Allow minimum number of personnel in the area • Consider the environmental vs. extinguishment impacts with the use of Class B foams. • A visible foam blanket does not ensure sufficient vapor suppression. Regularly monitor the area with a CGI to confirm the effectiveness of the foam blanket. Reapply foam when flammable vapors approach 10% of the LEL.
Damming consists of building a barrier across a waterway to stop/control the product flow and trap the liquid or solid contaminants. There are two types of dams:
• An overflow dam is used to trap sinking heavier-than-water materials behind the dam. • An underflow dam is used to trap floating lighter-than-water materials behind the dam.
How a BLEVE occurs
• Any fire on the vapor space will heat the tank shell faster than any fire impingement on the liquid area. • By the time the steel reaches 1800°F, it has lost 90% of its strength. Thinned and weakened from the fire, the tank will eventually relieve pressure to the outside through a split in the tank in the form of a jet flame or the container will fail. • Not every LPG tank exposed to fire fails by BLEVE. Sometimes the tank just splits open at the weld seam and burns off, and sometimes the pressure-relief valve functions and burns off the LPG, There is no way to accurately predict how and when any type or size of tank will fail. A functioning pressure-relief valve is not an effective way of predicting whether a tank will fail.
Basic cooling water guidelines for exposed tanks and pressure vessels are as follows:
• Atmospheric storage tanks up to 100 ft diameter require 500 gpm. • Atmospheric storage tanks from 100-150 ft diameter require 1000 gpm. • Atmospheric storage tanks exceeding these diameters require 2000 gpm. • Pressure vessels should have a minimum of 500 gpm applied at the point of fire impingement.
Examples of defensive tactical options that can be used to buy time until the most effective offensive tactic can be implemented include the following:
• Barriers - place a physical barrier between the hazmat, its container, and exposures. (Dikes or dams). • Distance - separate the people from the hazmat • Time - reduce the duration of the release or exposure time • Techniques - (i.e., uprighting a leaking liquefied gas cylinder so vapors, not liquid product, will be released).
One of the first concerns after sizing up the incident is search and rescue. No matter the nature of the rescue operation, the first law of hot zone operations is that personnel working in the hot zone must be prepared, as follows:
• Be trained to play • Be dressed to play • Use the buddy system. • Have backup capability • Have an emergency decon as a minimum • Have the IC's approval for the entry/rescue operation.
Key tasks in implementing a mayday event include the following:
• Declare a mayday by announcing, "MAYDAY, MAYDAY, MAYDAY,' to maintain priority radio traffic. Without unkeying the radio mic, provide the following information: - WHO - WHAT - WHERE - NEEDS • Begin self-assessment/self-rescue techniques. • Maintain radio contact with command. Command should immediately acknowledge the mayday and start the mayday protocol by activating the backup team and a rescue team. • Switch to an alternate radio channel to prevent radio interference. • Immediately establish a second backup team.
Almost all gasoline sold as a motor fuel in the United States contains up to 10% fuel grade ethanol in regular unleaded gasoline.
• E10 = 10% ethanol. 90% gasoline. • ethanol is a polar solvent (i.e., totally soluble in water) and gasoline is a hydrocarbon (i.e., low solubility in water). • regular Class B firefighting foams are not effective on polar solvents.
Vacuum trucks may be used for picking up spilled liquid products, as well as offloading atmospheric pressure and low-vapor-pressure hazardous materials. The following safety precautions should be observed when using vacuum trucks within hazard control zones:
• Flammable atmosphere test. • Grounding. • Venting (vent downwind of the truck) • Personnel safety (control ignition sources within 100' of the truck and discharge of the venting).
The hazard and risk evaluation process for reactive chemicals should focus on the following factors:
• Hazardous nature of the material involved. • Quantity of the material involved. . Design and construction of the container. • Type of stress applied to the hazmat and/or its container. • Fixed or engineered safety systems. • Size and type of area being affected. • Identifying and prioritizing exposures. • Level of available resources. • Criminal or terrorist activity.
The IC must use an organized approach to developing a plan of action. This approach includes the following:
• Identifying realistic and measurable incident objectives • Defining the operational time frame under which the plan must be executed • Determining the organizational structure of the players on the scene • Identifying the known or potential hazards at the scene and the mitigation efforts that make those hazards go away • Specifying how the responders will communicate and what actions they will take if something unexpected happens or things go wrong • Determining how to communicate all information to those tasked with any part of executing the game plan
For potential BLEVEs The IC must determine (1) if an adequate volume of water is available for cooling (2) if there is enough pumping capacity for the required water pressure at the fire scene.
• If an adequate water supply is not available for cooling primary exposures, the IC must consider immediate withdrawal of all personnel from the hazard area. • tanks can fail within 10 to 20 minutes of direct flame impingement, or they can fail days later, after the container is initially stressed.
When may controlled burning be an appropriate tactic for reactive materials?
• If extinguishing a fire will result in large uncontained volumes of contaminated runoff, further threaten the safety of both responders and the public, and lead to more extensive clean-up problems. • sometimes used at fires involving agricultural chemical facilities or industrial facilities.
Several major fires have involved pool chemicals (i.e., calcium hypochlorite, chlorinated isocyanurates).
• If large quantities are involved in fire, manufacturers recommend using copious amounts of water to extinguish the fire. • this may be a trade off though with air and water pollution.
What are the guidelines for search and rescue operations in a confined space and hazardous atmosphere?
• If the victim has been in (1) an oxygen-deficient atmosphere of less than 19.5%, (2) a flammable atmosphere of 10% or greater, or (3) a toxic atmosphere above the PEL/TLV for periods longer than 5 to 15 minutes, the IC should consider the possibility that there is no chance for a successful rescue. • Also must consider the amount of time it takes to set up and safely conduct search and rescue operations.
Liquid and vapor dispersion of LNG
• LNG has an expansion ratio of 600:1 when vaporized at 1 atmosphere and warmed to room temperature. • LNG is prone to Auto-refrigeration. • LNG itself will not burn or explode. LNG must be vaporized and mixed with air in the right concentrations (5-15%).
LNG pool fire
• LNG released from a storage tank or transfer pipeline can form a liquid pool. As the spill forms, some of the liquid evaporates. If the vapors encounter an ignition source, the vapors will ignite, and flame will travel back to the origin of the spill, resulting in a pool fire. • Spraying water on an LNG pool only increases the vaporization rate and intensifies any fire. • The preferred extinguishing agent for small LNG fires is a dry chemical agent such as potassium bicarbonate (i.e., Purple K).
Ludwig Benner coined the term MOTEL, an acronym for the following five factors that can be influenced in the outcome an emergency:
• Magnitude • Occurrence • Timing • Effects • Location
What are the 3 operational modes?
• Offensive • Defensive • Nonintervention
Offensive mode
• Offensive mode operations commit the IC's resources to aggressive leak, spill, and fire-control objectives. • the risk may be justified if rescue operations can be quickly achieved, the release can be rapidly confined or contained, or the fire can be quickly extinguished.
Considerations with flaring operations:
• One drawback of flaring is the time needed to burn off the product (liquid flaring is preferred over vapor). • Must consider the safety, disruption to transportation systems and businesses, and the safety and speed of other tactical options. • Auto-refrigeration is also a concern with LPG.
Common scenarios for leaks on nonpressure IMO containers include:
• Overfills (the container must be cooled to reduce the internal pressure and the effects of the ambient heating). • Mystery leaks (water from insulation. Still test for pH) • Bottom outlet leaks. • Container shell leaks • Top fittings and manhole leaks
Reactive chemicals are a broad family of materials including:
• Oxidizers • Organic peroxides • Certain flammable solids • Hypergolics • Pyrophorics • Various water-reactive substances
most common source of leaks encountered on the MC-306/DOT-406 flammable and combustible liquids cargo tank truck.
• Piping and valve leaks (most common). • Splits, tears, punctures, and irregularly shaped holes. • Pressure-relief devices, vents, and rupture disks (If liquid is being released from a pressure-relief device, it has probably failed. Don't block off this device) • Dome cover leaks
Selecting the best strategy involves weighing what will be gained against the costs of what will be lost. Determining what will be gained involves weighing many different variables, including the following.
• Potential casualties and fatalities • Potential property damage or financial loss • Potential environmental damage • Potential disruption of the community • Political considerations
6 different types of strategies
• Rescue • Public protective Actions • Fire control • Spill control • Leak control • Recovery
What is Adsorption?
• The chemical process in which a sor-bate (liquid hazardous material) interacts with a solid sorbent surface. • Adheres to the surface. • Example is Activated Carbon • The adsorption process is accompanied by the heat of adsorption, whereas absorption is not. Therefore, spontaneous ignition may be a possibility with some liquid chemicals. • mostly used for liquid spills on land and should be nonreactive to the spilled material.
Considerations for using the water injection as a mitigation tactic include:
• The container must have a liquid leak. • Water injection can also be used to transfer product and/or flare propane from an intact container. • Minimize the effects of auto-refrigeration. • there must be enough room in the tank for the water to be added to the level necessary to cover the leak.
What is Flaring?
• The controlled burning of a liquid or gas material to reduce or control pressure inside the tank, dispose of residual vapors, and/or dispose of a product when transfer operations may be impractical.
What is venting?
• The controlled release of a material to reduce and control the pressure and decrease the probability of a violent container rupture. • typically limited to nonflammable gases.
Situations well-suited for aggressive leak-control offensive strategies include the following:
• The hazmat is a vapor or gas and threatens to migrate away from its container. • The hazmat is in a solid/powder form and weather conditions threaten to carry it from its original site. • Previous defensive options have not worked. • The situation is getting worse and increasing in risk as time progresses.
Things to consider with Conflicting or uncertain information:
• The more critical the life safety situation, the less likely it is that the IC will have enough accurate and reliable information to make an informed decision. • At the same time, the worse the potential outcome, the more uncertainty the IC should accept using response goals and objectives.
What is Absorption?
• The physical process of absorbing or picking up a liquid hazardous material to prevent enlargement of the contaminated area. • are effective when dealing with liquids in amounts less than 55 gal
What is Water Injection?
• The process of forcing or injecting water into a propane container at a pressure that is greater than the container pressure to convert a liquid propane leak to a water leak. • The water replaces the propane at the bottom of the tank and is released from the damaged tank, valve, or pipe in place of the propane.
Vent and burn is normally an option of last resort. It should only be used under the following conditions:
• The rail tank car or cargo tank truck has been exposed to fire. • Conditions do not allow the safe transfer, venting, or flaring of the pressurized container. • Site conditions don't allow rerailing or offloading. • Fittings and valves can't be repaired.
Observe the following rules regarding the compatibility of Class B foams:
• There is no drop-in replacement SFFF for AFFF. • On the emergency scene, concentrates of a similar type (i.e., all AFFFs, all fluoroprotein) but from different manufacturers may be mixed together immediately before application. However, SFFF concentrates from different manufacturers cannot be mixed.
The decision to either (1) offload the contents and then upright the container, or (2) upright the container while still loaded, is dependent on several variables. These variables include the following:
• Type of cargo tank truck involved. • Nature of container stress and damage. • Location of the incident. • Resources available to lift the damaged container. • There is one universal rule: never upright a loaded aluminum shell MC-306/DOT-406 cargo tank truck. Everything else will be incident specific.
What is Hot Tapping?
• Used to gain access to bulk liquid or gas tanks, pipelines, or containers for product removal. It involves the welding of a threaded nozzle to the exterior of a tank or pipeline. Hoses are then attached to the valve outlet and the contents of the tank are removed.
Offensive tactics for flammable liquid emergencies
• Used when enough water, firefighting foam supplies, and related resources are available for a continuous, uninterrupted fire attack. • Recommended application time of foam is 15 minutes for flammable liquid spill fires and 65 minutes for Class I flammable liquid storage tank fires.
What is Scrubbing?
• Usually associated with venting and involves the use of physical or chemical filters or control devices to scrub contaminants, particulates, or gases during normal or emergency process operations. • When activated, an emergency scrubber can normally filter or neutralize 100% of the accidental discharge.
Flammability of LNG
• When LNG is spilled and its vapors come into contact with an ignition source, the spill will become a pool fire and present a thermal radiation hazard. If there is no ignition source, the LNG will vaporize rapidly forming a cold gas cloud that is heavier than air. The cloud will spread and be carried downwind until it reaches neutral buoyancy when enough air mixes with it. • The vapor is ignitable in the 5 to 15% range.
In a confined space, when are SARs a good option? When are they not practical?
• While working in a limited egress condition. • May not be practical for confined spaces like pipelines and sewers due to the 300' hose limit.
What is dispersion?
• a chemical method of confinement by which certain chemical and biological agents are used to disperse or break up the material involved in liquid spills on water. The use of dispersants may result in spreading the hazmat over a larger area. • often applied to hydrocarbon spills, resulting in oil-in-water emulsions and diluting the hazmat to acceptable levels.
Where do leaks usually come from on cargo tank trucks?
• damaged tank appliances and attachments (dome covers and piping). • the tank itself
Offensive tactics for reactive materials
• implemented when enough resources are available to control and extinguish the fire. However, unless responders see the fire or chemical reaction in its initial stages, they often have limited offensive tactics to change the sequence of events.
What is Plugging?
• involves putting something into a breach or opening to reduce the size of the hole and the amount of product flow. • must be compatible with both the material and the container to be effective.
Examples of tactics for pressure isolation and pressure reduction:
• isolating valves • venting • scrubbing • flaring • water injection • hot tapping • vent and burn • solidification • vacuuming
Defensive mode
• less aggressive objectives. • concede certain areas to the emergency and direct the efforts of responders toward limiting the overall size or spread of the emergency.
Defensive tactics for reactive materials
• protecting exposures while letting the fire burn or the reaction run its course. • may include using a controlled burn, remotely transferring the product to another container, remotely injecting a stabilizer into the reaction, or disposing of the decomposition products by sending them to a flare or scrubber.
Nonintervention mode
• taking no action other than isolating the area. • responders wait out the sequence of events underway until the incident has run its course and the risk of intervening has been reduced to an acceptable level.
tactical recommendations for dealing with gasoline ethanol mixtures can be summarized as follows:
•Regular Class B firefighting foams (i.e., AFFF, fluoroprotein foam) will not be effective for ethanol or for gasoline-ethanol mixtures > than 10% ethanol. • Overall, alcohol-resistant AFFF is the best agent for dealing with both ethanol and gasoline ethanol blends.
