Chapter 4 Flashcards
When an incident requiring technical search and rescue occurs, the execution of a safe and successful response often depends on the evaluation and planning that the AHJ has undertaken before the response.
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Identifying the potential for technical search and rescue situations within a jurisdiction is the first step in the pre-incident process
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Any analysis of the hazards and assessment of the risks within a given response area must take into account the environmental, physical, social, and cultural factors involved.
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Soil conditions influence the potential for cave in incidents and responders should familiarize themselves with the types of soil in all parts of their jurisdiction.
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Visual inspections of buildings under construction will enable first responders to address or plan for concerns before they become a problem.
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The plan for each rescue discipline must reflect the level of operational capability that the jurisdiction possesses in that discipline.
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Planning for resource needs should include the plans for incident management personnel and the appropriate decision makers to form a unified command if indicated.
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Both agencies entering into a mutual aid agreement should sign the agreement before there is a need for their respective resources.
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As part of the deployment plan, various alternatives should be tested in one or more realistic training exercises.
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Periodically exercising the plan is important to maintain operational readiness in light of changing conditions and personnel turnover.
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Site surveys contain information that Incident commanders can use to develop an effective incident action plan and improve the ability of responders to respond in a safe and effective manner to any incident.
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Site surveys should be developed for facilities or features that present responders with unusual hazards based on the type or frequency of responses.
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Resources that may assist in the development of a site survey for a body of water include reports of previous incidents, flood insurance maps, tide tables, and meteorological data.
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Most of the hazards associated with technical search and rescue operations fall into one or more of the four categories: physical hazards, environmental hazards, water hazards, and atmospheric hazards.
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Physical hazards in confined spaces may be created by the lack of structural integrity of the space or by hazardous objects within the space.
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Physical hazards associated with trench rescues include the lack of structural integrity or trench walls and or hazardous objects near the trench.
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At industrial sites, fall hazards can vary from elevated work areas to subterranean pits.
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Building collapse and trench rescues present scenarios where responders must move vertically during ingress or egress form the scene.
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At the scene of a trench rescue, the probability of an additional collapse of the trench walls is present as long as the trench remains open.
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The fact that a wall has already caved in is ample evidence that the soil is unstable.
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The potential for a subsequent collapse is even greater in soil that has been disturbed or is subject to conditions such as seeping water.
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Two factors that have a significant effect on the stability of trench walls are surcharge loads and vibration.
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Surcharge load - any weight near the trench lip that increases instability of a trench’s walls or lip, or increases the likelihood of secondary cave in, often imposed from the soil pile or heavy equipment.
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Spoil pile - excavated materials consisting of topsoil or subsoils that have been removed and temporarily stored during the digging of a trench.
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Machinery that is used to move free flowing materials may further the engulfment hazard by causing the materials to fill the vessel.
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Before responders enter areas presenting engulfment hazards, all machinery and equipment that could produce movement or shifting of materials must be shut off and marked with a lockout/tagout device.
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Water increases the structural load of a building, decreases soil stability, and may become a drowning hazard.
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As much as possible, responders should avoid conducting rescue operations in areas of suboptimal lighting.
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Sound dampening and reflection in confined spaces and trenches impair communication in these environments.
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Moisture is commonly present within confined spaces, trenches, and structural collapses.
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Wet floors can slow rescue efforts due to poor footing and can turn the dust common in a collapsed building into a slippery slurry.
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Decomposition of organic materials buried under rubble and debris is also a source of biological contamination.
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The initial assessment of a swift water incident begins with a daily evaluation of conditions within the jurisdiction.
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Two causes of currents in water include:
Laminar flow - combination of gravity acting on water and water’s movement against the river bottom.
- smooth, non turbulent flow of a fluid that occurs at low velocities.
Helical flow - Effect of water’s movement against the shore.
- the corkscrew like flow of water.
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The laminar flow travels down the center of the body of water, which takes the victim or the rescuer downstream.
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The helical flow cuts in at the shoreline pulling the victim or the rescuer out into the laminar flow.
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River flow patterns include different types of currents that affect search and rescue operations.
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Particulate matter, such as silt or algae, may create turbidity which limits the responders’ ability to spot and avoid subsurface hazards.
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Turbidity - muddy, cloudy, or murky condition of water caused by the stirring up of sediment.
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An eddy is a segment of water that is moving opposite to the main flow of the current usually because of contact with a rock or other obstruction in the waterway.
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Eddy - A current of water moving in opposition to the main stream, caused by contact with an obstacle.
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Underwater strainers and above surface sweepers may be formed by fallen trees, abandoned vehicle chassis, or construction debris.
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Strainers - obstructions in a waterway within the water itself just below the waterline.
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Strainers and sweepers allow water to flow through but trap objects.
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Also known as a diversion dam, the low head dam is one of the more dangerous hazards a water rescuer may encounter.
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Commonly called the drowning machine, the hydraulic action of this dam is virtually impossible to escape.
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Obstructions above and below the water surface will influence the actions possible at a search and rescue incident.
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Low head dams create a powerful current that can trap people and objects indefinitely.
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Examples of atmospheric hazards that may be encountered at many technical search and rescue incidents include: Accumulation of harmful gases, lack of oxygen, oxygen enrichment.
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An atmosphere is considered to be oxygen deficient whenever the concentration of oxygen drops below 19.5 percent.
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Oxygen deficiency can result from biological activity such as fermentation, a fire or other oxidation process, or another gas displacing the available oxygen in a space.
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Spaces shown to be oxygen deficient should be mechanically ventilated until atmospheric monitoring shows readings within safe levels.
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Any atmosphere within a confined space that exceeds 23.5 percent oxygen is defined as an oxygen enriched atmosphere.
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If the atmosphere within a confined space or trench contains flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit, it is considered hazardous.
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Mineral dust and other fine airborne particulates are common to some confined spaces.
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In the static atmosphere of a confined space or trench, dust can remain suspended in the air for hours.
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The LFL of airborne combustible grain dust can be approximated when the dust obscures vision at a distance of 5 feet or less.
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The atmosphere should be sampled at the top, middle, and bottom of the space, or at four feet intervals.
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Sampling the atmosphere helps determine the need for mechanical ventilation and the type of respiratory protection required for rescuer safety.
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Risk benefit analysis - comparison between the known hazards and potential benefits of any operation, used to determine the feasibility of the operation.
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An important aspect of this determination is the risk benefit analysis which evaluates the benefits to be gained compared to the risks that must be taken to complete an operation.
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IFSTA has developed a model guideline for conducting a risk benefit analysis that is consistent with both NFPA 1500, standard on fire department occupational safety and health program.
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Team integrity is vital to safety and must always be emphasized.
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No property or un-savable individual is worth the life of a responder.
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The safe and efficient response to a technical search and rescue incident requires an in depth and well thought out pre-incident plan for the response.
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A pre-incident site survey is one tool that can assist responders with developing an incident action plan.
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All response operations should occur within the framework of a risk benefit analysis model.
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