trench rescue operations - maryland fire and rescue institute

Note Taking Guide

Rescue Technician—Trench Rescue

Operations

Maryland Fire and Rescue Institute University of Maryland

Steven T. Edwards

Fall 2009

Copyright© 2009 by the Maryland Fire and Rescue Institute. All rights reserved. No part of this book may by copied or reproduced in any form or by any means without written permission of the Maryland Fire and Rescue Institute.

The Maryland Fire and Rescue Institute of the University of Maryland is the State’s compre-hensive training and education system for all emergency services. The Institute plans, researches, develops, and delivers quality programs to enhance the ability of emergency service providers to protect life, the environment, and property.

1

Trench Rescue Operations

Lesson 1-1Introduction to Trench Rescue

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Student Performance Objective

Given information from discussion, handouts, and reading materials, describe trench rescue operations. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

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Overview

Technical Rescue DisciplinesThe Big ThreeThe Specialized Training CycleService LevelsAdditional Requirements for Certification Levels

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Overview

The Risk-Benefit AnalysisThe FAILURE AcronymTypes of Service LevelsThe TeamGetting Your Equipment to the Scene

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Overview

OSHA Subpart P—Excavations, 29 C.F.R. §1926General Requirements of Trench RescueOSHA and Trench RescueTrench Collapse Emergencies

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Overview

The Trench Incident Management SystemLevels of the Incident Management SystemLogistics Support Functions

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Technical Rescue Disciplines

Technical Rescue Disciplines• Trench rescue• Rope rescue• Vehicle and machinery rescue• Swift water rescue• Confined space rescue• Structural collapse rescue

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The Big Three

Special people are• Different from traditional fire and rescue

service providers• Expected to operate in dangerous

environments• Expected to think clearly in dire situations• Required to participate in intense training

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The Big Three

Special equipment is• Vitally important to the rescue effort• Required to do the job safely and effectively• Specialized and highly technical• Difficult to maintain• Expensive to operate

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The Big Three

Special training must be• Solid, realistic, and practical• Done often

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The Specialized Training Cycle

Continuous recruitment, skill development, and equipment evaluation and updates

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Service Levels

Awareness responders are• Able to identify hazards and dangers• Able to use a decision-making matrix• Not actively involved in the rescue operation• Educated to avoid being part of the problem

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Service Levels

Operations responders• Are at the lowest level of certification• May be responsible for initial and long-term

rescue operations• Are called “support personnel”• May place sheeting or shoring systems in

some trenches• May function as sector officers

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Service Levels

Technician responders have• Additional trench rescue training• Additional responsibilities• Technical rescue skills package training

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Service Levels

Instructors• Have received certification• Are certified in course development• Should be active rescue team members

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Additional Requirements forCertification Levels

NFPA 1670, Chapter 11• Awareness

Trench rescue awarenessConfined space rescue awareness

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• OperationsTrench rescue operationsRope rescue operationsVehicle and machinery rescue operations

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• TechnicianTrench rescue technicianConfined space technicianVehicle and machinery rescue technician

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NFPA 1006, Chapter 8• Job performance requirements• Knowledge, skills, and abilities for fire

service personnel who perform trench rescue operations

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The Risk-Benefit Analysis

Is this a rescue or a recovery?What is the risk to the rescuer?What is the benefit to the situation?What is the difference between head versus heart decision making?

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The FAILURE Acronym

“F” Failure to understand the environment “A” Additional medical implications not considered “I” Inadequate rescue skills “L” Lack of teamwork and experience “U” Underestimating the logistical needs of the operation “R” Rescue – recovery mode not considered “E” Equipment not mastered

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Types of Service Levels

The self-sufficient team• Commits to many hours of training • Must have a considerable amount of

specialized equipment• Must have a means of transporting the

specialized equipment• Is the most expensive method of service

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The community-dependent team utilizes• Those with construction and excavation

experience• A “call-back” list• A logistical needs and supply list

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The regional approach team• Is the most cost effective• Spreads the cost over several jurisdictions• Requires written mutual aid agreements• Is very hard to organize and maintain

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The Team

The team members must be:• Physically fit• Mentally fitThe team must have:• Members that are proficient in construction

skills• Medical personnel as members• People that “think on their feet”• People in the best positions for their abilities

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Getting Your Equipment to the Scene

A squad truck A dump truck or a flat-bed vehicle A trailer configuration A custom or converted vehicle A pod system A rescue truck

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Getting Your Equipment to the Scene

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OSHA Subpart P—Excavations,29 C.F.R. § 1926

Provides data and information on appropriate protective systemsCan be universally applied in a rescue situationProvides the requirements to qualify the user as a competent personWas originally part of the “Contract for Hours Worked Standard Act”

RES 206-PPT-1-1. 29

The General Requirements ofTrench Rescue

Are the same as the guidelines used in construction operationsInclude rescue safety and operational guidelines• Protection exceptions: All trenches must be

protected before entry exceptThose made entirely of stable rockThose less than five feet in depth

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• Protection: Any trench five feet deep or more must be protected (may include the height of the spoil pile)

• Spoil pile: must be set back two feet from the lip

• Egress: Trenches 4 feet deep or greater in depth must have a means of egress every 25 feet

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• Atmospheric hazards: All trenches should be tested for

Oxygen deficiency or enrichmentHazardous atmosphereFlammable gases

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• A competent person must be able to determine the soil classification

• Water accumulation: employees need to be protected from water by dewatering operations and/or a lifeline

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• Inspection: A competent person must inspect the trench for the following

Secondary cave-in potentialProtective systems failureAtmospheric monitoring or controlOther hazardous conditions

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OSHA and Trench Rescue

OSHA requires compliance under certain conditions• An employee/employer relationship

exists• Trench rescue operations are part of

your job• You are paid for your service

RES 206-PPT-1-1. 35

OSHA and Trench Rescue

OSHA’s view of trench rescue operations• Trench rescue operations tend to over-

engineer protective systems• Rescue protective systems are used for

hours, not days• Rescue operations have a different mission

than construction• OSHA will get involved in the operation for

certain reasons

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Trench Collapse Emergencies

Emergencies due to noncomplianceAccidents without a cave-in• Medical emergency• Trauma emergency

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Equipment failure and load management• A backhoe- or excavator-caused problem• Hydraulic failure• Rigging failure• Protective system failure• Utility failure

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Atmospheric concerns• Include buried hazardous materials• Require monitoring of the atmosphere• Require situational awareness

More than one ill victim in a trenchOne or more victims “down” in a trench

• May require a hazmat team response

RES 206-PPT-1-1. 41

The Trench Incident Management System

Is like any other IMS Requires an incident commanderDecreases the organizational span of controlProvides on-scene accountabilityIs dependent on the magnitude of the problem and the number of resources

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The Trench Incident Management System

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Levels of the Incident Management System

Is responsible for developing the strategic goals for the operation

Is responsible for all resources

The strategic level: The Incident Commander

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• The safety officer Is able to spot unsafe actsIs able to anticipate activities which will lead to accidentsIs able to control the “big picture”Is familiar with the environment and its potential hazardsConducts pre-operational briefings

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• The liaison officerHandles multiple agency interactionBuffers the IC from being overwhelmed

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• The public information officerProvides the media with a direct point of contactProvides frequent updates to the media

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The tactical level• The operations officer

Actually runs the incidentIs responsible for overall coordination of the rescueImplements tactical decisionsIs responsible for all groups providing direct emergency support

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• The logistics officer is responsible forProcuring equipmentProcuring personnel

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The task level• The medical officer

Reports to the operations officerIs responsible for establishing a medical control areaIs responsible for establishing a transportation sectionIs responsible for the rehabilitation section

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• The extrication officer is responsible forThe actual extrication of the victimAll activities required to facilitate the rescueThe pre-entry briefing

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Emergency support functions• The air supply operations team

Oversees pneumatic air shores and air bagsEnsures proper operation of equipmentSecures air supply

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• The cutting teamIs responsible for all cutting and manufacturing of wood systemsMust have members who are competent with sawsOperates at a cutting station

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• The panel teamSets up, carries, and installs all shields or panelsMust have at least four hard workersMay be reassigned after the panels are set

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• The shoring teamAssembles and installs all shores and walers of the protective systemHas members who– Have manual dexterity– Are efficient with hand tools

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• The rigging teamEstablishes lifting systemsMust have systems ready to use

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• The heavy equipment operatorMust have experience and talentMay be needed to create a slope or a bench systemMust position carefully so as not to cause a secondary collapseMust understand hand or communication signals

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• The rapid intervention team/crew members

Must be ready before stabilization activityMust be equipped for medical emergencies and secondary collapsesMay be rotated to gain experience in the actual rescue

RES 206-PPT-1-1. 58

Logistics Support Functions

Logistics Support Functions• Are responsible for equipment storage and

dissemination• Use a predetermined location• Employ a staging officer

RES 206-PPT-1-1. 59


Given information from discussion, handouts, and reading materials, describe trench rescue operations. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

21

RES 206-PPT-1-1. 60

Review

Technical Rescue DisciplinesThe Big ThreeThe Specialized Training CycleService LevelsAdditional Requirements for Certification LevelsThe Risk-Benefit Analysis

RES 206-PPT-1-1. 61

Review

The FAILURE AcronymTypes of Service LevelsThe TeamGetting Your Equipment to the SceneOSHA Subpart P—Excavations, 29 C.F.R. §1926The General Requirements of Trench Rescue

RES 206-PPT-1-1. 62

Review

OSHA and Trench RescueTrench Collapse EmergenciesThe Trench Incident Management SystemLevels of the Incident Management SystemLogistics Support Functions

1


Lesson 2-1Soil Assessment and

Types of Trench Collapse

RES 206-PPT-2-1.1


Given information from discussion, handouts, and reading materials, describe soil physics and conditions that lead to collapse. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

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Overview

Soil PhysicsNon-entry Rescue ScenarioPhysical Forces Associated with CollapseConditions and Factors that Lead to Collapse

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Overview

Spoil Pile SlideSlough FailureRotational FailureShear Wall CollapseToe FailureBell Pier ConditionWedge Failure

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Overview

The Importance of Soil ClassificationTypes of SoilSoil Testing Procedures

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Soil Physics

Gravity is the force that draws everything to the center of the earthHydrostatic pressure is the increased pressure caused by the addition of water to the soil profile• Dry soil weighs between 60 and 80 lbs per

cubic foot • Water-saturated soil may weigh up to 150

lbs per cubic foot

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Soil Physics

Unconfined compressive strength (UCS) is the amount of resistance the soil has to pressure• A higher UCS reflects a more cohesive soil• A lower UCS reflects a less cohesive soil

RES 206-PPT-2-1.7

Soil Physics

Active soil has a tendency to move due to• The failure or removal of a protective

system• The inability of the soil to hold its own

weightPassive soil does not have a tendency to move

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Non-Entry Rescue Scenario

A worker has fallen from a ladder and broken his legA spoil pile is next to the trench The trench walls are of concern The collapse potential is very highThe victim is offered a ladder and a ropeThe victim climbs the ladder while tied to the ropeThe trench wall collapses after the victim is outNo rescuers were injured while performing this rescue

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RES 206-PPT-2-1.9

Physical Forces Associated with Collapse

Weights• A cubic foot of soil weighs between 85 and 150 lbs

with an average weight of 100 lbs• A cubic foot of water weighs 62.4 lbs• A cubic foot of rock weighs 165.36 lbs• A cubic foot of 1/2 rock and 1/2 air mix weighs about

82.68 lbs per cubic foot• A cubic foot of 1/2 rock and 1/2 water mix weighs

about 113.85 lbs per cubic foot

RES 206-PPT-2-1.10


Forces• Vertical pressure

Represents forces that may compress a victimCauses wall failure when tension overcomes cohesion

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• Lateral pressureIs about 33% of the vertical pressure at a given depth Is 132 pounds per square foot at four feet deepIs distributed at about a 45º angle from the bottom of any given planeIs responsible for rotational failure

5

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• Rotational failureIs the most prevalent type of collapseIs caused by lateral pressureIs most dangerous 1/4 of the depth up from the bottom of the trench

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• Shoring pressureActs to transmit pressures from one side of the trench to the otherActs to equalize pressures May be overcome by lateral pressure, causing– A collapse– Shoring failure

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Conditions and Factors that Lead to Collapse

The addition of water• Adds weight to the soil• Presents an absorption rate issue• Causes a loss of strength of the soil

Initially the soil may gain strength When saturated the soil will lose strength

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The freestanding time allows• Environmental issues to become an concern• Compressive forces to cause failure• Time for nature to attempt to fill the trench

back in

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The varying soil profiles• Cause problems determining the

classification of the soil• Cause problems determining the soil’s

potential for collapse• Have different soil coefficients

Sand may be layered between clayThere may be a slip potential

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Water may• Provide a slip fault• Be running water

Underground streamsAquifers

• Be released from saturated soil

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The water table may• Dictate the rescue situation• Be just below the surface• Be quite deep

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The previously disturbed soil may be easy to spot because it may contain bottles, bricks, manmade objects, landfill, etc.

The soil may be difficult to interpret because it lacks cohesiveness

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The location of heavy equipment may cause pressure on unprotected trench walls

The placement of emergency equipment should be kept back 300 feet and should not add to surface weight or scene vibration

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The spoil pile may• Be less than two feet from the lip• Cause multiple problems

Vertical and lateral pressure due to weight

Active soil sliding down the trench wall

A restricted work area

RES 206-PPT-2-1.22


Vibration• From road traffic• From machinery

RES 206-PPT-2-1.23

Spoil Pile Slide

Spoil pile slide due to overburden pressureSpoil pile slide due to the angle of repose• The angle is too steep• The soil has dried, becoming less cohesive • The soil is active

9

RES 206-PPT-2-1.24

Spoil Pile Slide

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Slough Failure

Is a loss of part of the trench wallIs a type of rotational failureMay have a scoop-shaped appearance May be a result of unconfined hydrostatic pressure

RES 206-PPT-2-1.26

Slough Failure

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RES 206-PPT-2-1.27

Slough Failure

May be due to the spoil pile being too close to the trench lip, causing vertical and lateral pressureMay be indicated by cracks in and around the surfaceMay be indicated by multiple soil layersMay occur suddenly and without warning

RES 206-PPT-2-1.28

Rotational Failure

May have a half-moon shape that starts back from the trench lipMay result in large sections of trench wall fallingMay appear to have been dug by a spoonMay create a very difficult problem to overcome with a rescue system

RES 206-PPT-2-1.29

Shear Wall Collapse

Occurs when a section of the wall loses its ability to standUsually happens across a vertical planeMay be caused by cracks in the surface• Water may wash out dirt• Washing and drying create deeper cracksIs normally associated with cohesive soilsMay cause a larger collapse

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RES 206-PPT-2-1.30

Shear Wall Collapse

RES 206-PPT-2-1.31

Toe Failure

Is a slough that occurs at the bottom of the trenchIs characteristic of a cantileverMay be caused by a sand pocket

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Toe Failure

May be caused by the effects of water at the bottom of the trenchMay not be detected if a rescuer is standing above it Is hard to correct until a protective system is in place

12

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Toe Failure

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Bell Pier Condition

Is a toe failure on both sides of the trenchIs the result of water conditionsIs usually a slow process

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Bell Pier Condition

13

RES 206-PPT-2-1.36

Wedge Failure

Occurs in intersecting trenchesIs characterized by an angle section of the trench wall falling from the corner of two intersecting trenchesCan be suddenCan be catastrophic

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Wedge Failure

RES 206-PPT-2-1.38

The Importance of Soil Classification

Soil classification• Determines the performance of a soil• Is based on a decreasing order of stability• Is conducted in each of the layers of soil• Is determined by the least stable soil• Is used to determine the protective system

14

RES 206-PPT-2-1.39

The Importance of Soil Classification

Soil classification must be based on two tests• A visual test• A manual test

RES 206-PPT-2-1.40

Types of Soil

Stable rock• Is the least dangerous • Is a natural solid material that can remain

standing after excavation• May fall on a worker after being excavated

and set in a loose pile• May present with other emergencies

FallsEquipment failure

RES 206-PPT-2-1.41

Types of Soil

Type A soils• Are cohesive materials with an unconfined

compressive strength of 1.5 tons per square foot or greater

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Types of Soil

• Type A soils includeClaySilty clayClay loamSandy clay loamCemented soils

RES 206-PPT-2-1.43

Types of Soil

• Type A soils are not classified as type A if they have any of the following conditions

The soil is fissuredThe soil is subject to vibrationThe soil has been previously disturbedThe soil is part of a sloped soil layer that is steeper than 4 horizontal to 1 verticalThe material is subject to other factors that would require it to be classified as a less stable material

RES 206-PPT-2-1.44

Types of Soil

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RES 206-PPT-2-1.45

Types of Soil

Type B soils• May be cohesive materials with an

unconfined compressive strength greater than 0.5 tsf but less than 1.5 tsf

RES 206-PPT-2-1.46

Types of Soil

• Type B soils may be granular “cohesionless”material

Angular gravelSiltSilt loamSandy loamSandy clay loam

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Types of Soil

• Type B soilsMay be previously disturbed soilMay be downgraded type A soil

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Types of Soil

Type C soils• Are cohesive materials with an unconfined

compressive strength of 0.5 tsf or less

RES 206-PPT-2-1.49

Types of Soil

• Type C soils includeGranular soilsSandSoils from which water is freely flowing Submerged rock that is not stable Sloped or layered systems where the layers dip into the excavation at a slope of 4 horizontal to 1 vertical or steeper

RES 206-PPT-2-1.50

Types of Soil

C-60 soil• Was designated by Speed Shore• Is a moist cohesive soil or a dense granular

soil that does not fit into type A or type B classifications

• May be cut near vertically and will stand long enough to allow shoring to be properly installed

• Is permitted because OSHA allows for other classification tables

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RES 206-PPT-2-1.51

Soil Testing Procedures

The visual test• Visually inspect

Excavated materialSoil from the trench wallThe excavation site in general

RES 206-PPT-2-1.52


• Look for the followingLayers that change with depthThe weakest soilSoil that has been previously disturbedThe soil make upThe presence of utilities, mixed soil, similar particles of soil, fissures, spalling, cracks, hydrostatic forces

RES 206-PPT-2-1.53


The manual test is used to• Determine soil characteristics• Learn relative strength under force• Formulate the material’s ability to free stand

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The plasticity test• Is used to see if the soil may be deformed or

molded without a change in total volume• Is done by molding a wet or moist sample into

a ball and then attempting to roll it into a thread 1⁄8 of an inch in diameter and two inches long

• Is used to consider a soil’s cohesiveness if the threads do not crumble or if a two-inch thread can be held at one end without tearing

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The dry strength test• The dry strength test is performed to

determine the propensity of the soil to fissure

• If the soil is dry and crumbles on its own into individual grains or fine powder it is granular

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The dry-strength test (continued)

• If the soil is dry and falls into clumps and then smaller clumps that are difficult to break down, then it may contain

Clay and gravelClay and sandClay and silt

• If the dry soil breaks into clumps that do not break into smaller clumps without difficulty, it may be considered unfissured

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RES 206-PPT-2-1.57


The thumb penetration test• Is used to estimate the unconfined

compressive strength of cohesive soils• Is performed by extending a thumb against

an exposed sample and attempting to push through it

• Indicates type A soil By a ready indentionBy a difficult penetration

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RES 206-PPT-2-1.59


• The thumb penetration test indicates type C soil

By easy penetration of several inches by the thumbBy molding the soil with little effort

• The thumb penetration test should be done as soon as possible after excavation to prevent the environment from affecting the sample

21

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The drying test• Is used to determine the difference between

cohesive material with fissures, unfissured cohesive material, and granular material

• Is performed by drying a sample of soil that is 6 inches long and 1 inch thick

Fissured material behaviorUnfissured cohesive material behaviorGranular material behavior

RES 206-PPT-2-1.61


Penetrometer and shear vane tests• Are performed by field instruments that may

be used to determine unconfined compressive strength

• Are performed by applying force into the trench wall

• Work accurately when the soil has some moisture content

• Are read numerically

RES 206-PPT-2-1.62


22

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Laboratory testing• Is not practical on scene• Is complicated but accurate• Helps develop mathematical determinations• Uses samples from varying depths obtained

with an auger

RES 206-PPT-2-1.64


Given information from discussion, handouts, and reading materials, describe soil physics and conditions that lead to collapse. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-2-1.65

Review

Soil PhysicsNon-entry Rescue ScenarioPhysical Forces Associated with CollapseConditions and Factors that Lead to Collapse

23

RES 206-PPT-2-1.66

Review

Spoil Pile SlideSlough FailureRotational FailureShear Wall CollapseToe FailureBell Pier ConditionWedge Failure

RES 206-PPT-2-1.67

Review

The Importance of Soil ClassificationTypes of SoilSoil Testing Procedures

1


Lesson 2-2Trench Rescue Equipment/Trench Rescue Assessment

RES 206-PPT-2-2.1


Given information from discussion, handouts, and reading materials, describe trench rescue equipment and trench rescue assessment. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-2-2.2

Overview

Personal Protective EquipmentDevelopment of a Safe CultureEquipment for Trench Rescue OperationsCalculating the Weight of an ObjectGravityMovementMechanics

2

RES 206-PPT-2-2.3

Overview

Air Bags for Trench RescueCribbingWedgesTime of AlarmArrival at the SceneAssessment During the Emergency

RES 206-PPT-2-2.4

Personal Protective Equipment

Standard issue equipment• Should minimize the effects of weather• Should minimize trauma around machinery and

tools• Includes a jumpsuit or long-sleeve shirt and pant

combination, gloves, steel-toed boots, helmet, eye protection, hearing protection, safety vest

RES 206-PPT-2-2.5


Clothing• Turnout gear • Jumpsuits• Long-sleeved shirt and pant

3

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Gloves• Firefighting gloves• Standard leather garden gloves• Vehicle extrication gloves• Nomex flight gloves

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Head protection• A firefighting helmet• A heavy-duty construction helmet

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Eye protection• Helmet mounted protection (not

recommended) • Full-face goggles• Standard safety glasses

4

RES 206-PPT-2-2.9


Foot protection• Steel toed• Steel shanked• A high top boot

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Specialty items• Respiratory Protection

Dust maskSelf-contained breathing apparatusSupplied air breathing apparatus

RES 206-PPT-2-2.11


• Hearing protectionBlocks out high frequenciesAllows for communication

5

RES 206-PPT-2-2.12


• SkullcapsAre worn under the helmetAllow for the cooling action of sweatAre cooled with water

RES 206-PPT-2-2.13


• Leather chaps Should be used in the cutting areaMight prevent or deflect a chain saw injury

RES 206-PPT-2-2.14

Development of a Safe Culture

Does not happen over nightRequires hours of training and discipline

6

RES 206-PPT-2-2.15

Equipment for Trench Rescue Operations

Ground pads• Distribute weight over a greater area• Help to prevent secondary collapse• Come in different types

4’ × 8’ × ½” sheets of plywood2” × 12” × 10’ or 2” × 12” × 12’ pieces of lumber

RES 206-PPT-2-2.16


Types of SheetingInterconnected steel uprightsSheets of plywood/timberManufactured panelsHomemade panels– ShorForm– FinForm– Plywood

RES 206-PPT-2-2.17


7

RES 206-PPT-2-2.18


• Facilitating ease of use and storage of sheeting

Cut off the corners of the sheeting at a 45° angleDrill hand holds or holes for ropesUse strongbacks

RES 206-PPT-2-2.19


RES 206-PPT-2-2.20


• Placement Tie a rope through the panel holes and lower the panel verticallyForm a loop through which the strongback can be vertically lowered

8

RES 206-PPT-2-2.21


Timber shores• Are made in many dimensions• Are made from Douglas Fir• Must have a bending strength of not less than

1500 pounds per square inch • Must not exceed 20 feet in width• Are relatively low in cost• Can be cut to varying lengths• Are selected by a process

RES 206-PPT-2-2.22


Screw jacks• Have a boot end which fits over a piece of

wood• Are tightened by a thread and yoke

assembly• Are relatively inexpensive• Are not as strong as other shores• Must not be overextended

RES 206-PPT-2-2.23


Hydraulic shores• May have the shore and uprights as one unit• Are lowered into the trench and set entirely from

above• Are expanded using a five-gallon reservoir of

fluid• Are shut off from fluid and pump after

expansion• Do not work well if the walls of the trench are

not vertical or near vertical

9

RES 206-PPT-2-2.24


Pneumatic air shores• Come in a variety of lengths• Are made from lightweight tubular aluminum• Are quick, strong, and dependable• Have a multitude of extensions and

attachments• Are extended by using compressed air• Have a few disadvantages

RES 206-PPT-2-2.25


Tools and appliances• Shovel• Entrenching tool• Hammer• Duplex nails• Chain saw • Electric powered ventilation equipment• Ladders• Dewatering devices

RES 206-PPT-2-2.26

Calculating the Weight of an Object

Multiply the width by the depth by the length4’ × 2’ × 20’ = 160 cubic feetMultiply the cubic feet by the weight per cubic pound160 × 150 = 24,000 pounds

10

RES 206-PPT-2-2.27

Gravity

Gravitational terms• Gravity – The tendency of an object to be

attracted to another object in direct proportion to its mass

• Lifting – the action necessary to move anything

• Lowering – controlling the descent of an object

RES 206-PPT-2-2.28

Gravity

• Moving – exerting enough force on an object to move it

• Stabilizing – keeping the object from moving by applying a counterforce

• Friction – a measure of the amount of force it takes to move an object across the surface of another object

RES 206-PPT-2-2.29

Gravity

Center of Gravity• The point on a body around which the body’s mass

is evenly distributed• The point on a body where all forces of the earth’s

gravitational pull are equal• The junction of the horizontal, vertical, and diagonal

axes of an object • The absolute center of an object

11

RES 206-PPT-2-2.30

Movement

Moment of force• Is mass multiplied by the distance away

from the turning point or fulcrum• Is the amount of force rotating around the

fulcrum times the distance from the fulcrum

RES 206-PPT-2-2.31

Movement

The teeter-totter• The balance can be determined by

multiplying the bigger child’s weight by the distance he is from the fulcrum (100 lbs × 4 feet equals 400 lbs)

• The smaller child’s weight is divided into the 400 lbs to determine the distance he should sit from the fulcrum (400 lbs divided by 50 lbs equals 8 feet)

RES 206-PPT-2-2.32

Mechanics

The Theory of Mechanics• Energy

Is the capacity for doing work and overcoming resistanceIs how hard it is to push or pull something a distanceIs measured in feet/pounds, either in kinetic or potential energyIs what it takes to accomplish work

12

RES 206-PPT-2-2.33

Mechanics

• WorkIs the distance times force or force as it is applied to set it in motionIs explained by the climbing of a mountain – the climbing is the work

RES 206-PPT-2-2.34

Mechanics

Application of Mechanics• The creation of a positive output in a given

situation (mechanical advantage)• The ratio of the output of force a machine

exerts compared with the input force furnished to that machine to do the work

RES 206-PPT-2-2.35

Mechanics

Types of Machines• Class 1 lever

Has the fulcrum placed between the force and the loadHas a calculated mechanical advantage

13

RES 206-PPT-2-2.36

Mechanics

RES 206-PPT-2-2.37

Mechanics

• Class 2 leverIs most effective when moving objects on a horizontal planeHas the load between the force and the fulcrum

RES 206-PPT-2-2.38

Mechanics

14

RES 206-PPT-2-2.39

Mechanics

• Class 3 leverIs the hardest to understandHas the force located between the load and the fulcrum

RES 206-PPT-2-2.40

Mechanics

RES 206-PPT-2-2.41

Mechanics

• Inclined planesAre a form of simple machineWork by reducing the required force over timeMay be ladders in the trench rescue environment

15

RES 206-PPT-2-2.42

Mechanics

RES 206-PPT-2-2.43

Air Bags for Trench Rescue

• Low pressure bags use 7 psiLimited lift capacityHigher lift ability in height

• Medium pressure bags use 22 psi• High pressure bags use 80 to 120 psi

Lift a greater amount of weightAre unable to lift as high as a low pressure bag

RES 206-PPT-2-2.44


How air bags work• Air bags must have an air source• Air bags must have a regulator• The effectiveness of air bags is limited by the

compressibility of air and the inside surface area of the bag

• The lifting capacity of air bags is limited by the amount of bag surface area that can contact the object

16

RES 206-PPT-2-2.45


Using air bags• Determine the lift

Multiply the length of the bag times the width by the recommended operation pressure to obtain maximum lift capacityDetermine the weight of the object to be lifted and the surface area of the lift pointCalculate the lift capacity based on the contact surface area

RES 206-PPT-2-2.46


Using air bags (continued)

• Determine if a greater surface area is needed

• Determine if the lift is possible with the available equipment

RES 206-PPT-2-2.47


17

RES 206-PPT-2-2.48


High pressure air bags• Design

Rubber or neoprene materialSteel bands or KevlarA coarse surface A working capability of 80 to 120 psi

RES 206-PPT-2-2.49


• Drawbacks of high-pressure air bagsDo not lift very highMay need to be stacked only up to two– Always put the larger bag on the

bottom– The lift capacity is that of the smaller

bag

RES 206-PPT-2-2.50


• Durability of high-pressure air bagsVery durable Not field repairable

18

RES 206-PPT-2-2.51


Low-pressure air bags• Are flexible rubber bags• Are used to fill voids in trench walls• Are used to lift some objects• Operate at 7 to 12 psi• Will lift an object higher than a high-pressure

bag

RES 206-PPT-2-2.52


Low-pressure air bags• Will not lift the weight of a high-pressure bag• Are field repairable• Require a lot of air to accomplish a lift• May be used outside of the trench to lift

RES 206-PPT-2-2.53


19

RES 206-PPT-2-2.54

Cribbing

May become brittle when natural moisture content is lostIs required for anything being lifted in a rescueShould be no more than an inch from the item being lifted

RES 206-PPT-2-2.55

Cribbing

May be made from construction grade lumber• 2” × 4”• 4” × 4”• 6” × 6”

RES 206-PPT-2-2.56

Cribbing

20

RES 206-PPT-2-2.57

Cribbing

May be cut in varying lengthsMay be used in a cribbing system• 4-point crib system• 9-point crib system• Full-box crib system

RES 206-PPT-2-2.58

Cribbing

Will support varying amounts of weight• 4” × 4” cribbing will support 6,000 lbs per

contact point• 6” × 6” cribbing will support 15,000 lbs per

contact point

RES 206-PPT-2-2.59

Cribbing

21

RES 206-PPT-2-2.60

Cribbing

Is dependent on the quality of the ground Is used by stacking timbers in alternating rows to build systems• The rows should have a slight overhang to

the previous row• The height should be no more than three

times the diameter of the base

RES 206-PPT-2-2.61

Wedges

Are cut pieces of lumber that form an inclined planeAre used to fill voids of varying sizesAre used until a full piece of lumber will fit in the cribbing system

RES 206-PPT-2-2.62

Wedges

22

RES 206-PPT-2-2.63

Wedges

Are used to tighten objectsAre used to take up space between wales and uprightsAre used to tighten shores to uprights

RES 206-PPT-2-2.64

Time of Alarm

What happened?Why was the excavation work being done?Is the victim completely buried?Is the situation a trench collapse or some other form of injury in the trench?Will I have access problems?How is the weather?

RES 206-PPT-2-2.65

Arrival at the Scene

Who is in charge and what happened?Is there a language barrier?Is the collapse within your scope of operations? What are the injuries?What is the victim’s survivability profile?

23

RES 206-PPT-2-2.66

Arrival at the Scene

What type of protective system is/was in place?Do I have the resources to accomplish this mission successfully?Do I have a solid rescue plan?Have I given a preincident briefing to rescue personnel?Can I mitigate this rescue with a rapid non-entry rescue technique?

RES 206-PPT-2-2.67

Assessment During the Emergency

Evaluate constantlyAnticipate problemsConsider the following when looking for buried victims• The victim may be at the end of a pipe string• A flagstick may indicate trench depth

RES 206-PPT-2-2.68


Consider the following when looking for buried victims (continued)

• Laser target may provide helpful information• A competent person may know the location the

victim was last seen• Tapping sounds may be heard when listening in

the pipes for signs of life• Determining what the victim was doing at the

time of the incident may help determine his location

24

RES 206-PPT-2-2.69


Consider the following when looking for buried victims (continued)

• Exposed limbs may not be in normal orientation• A cell phone call to the victim may help in

locating him• Listening devices may be used to help locate

the victim

RES 206-PPT-2-2.70


Develop a rescue plan for the incidentHold a pre-entry briefing• Involve all members• Brief on safety matters• Brief on tactics and strategies

RES 206-PPT-2-2.71


The pre-entry briefing (continued)

• Identify all known hazards• Explain emergency signals• Identify the command structure• Explain radio frequencies• Explain tactical objectives

25

RES 206-PPT-2-2.72


Given information from discussion, handouts, and reading materials, describe trench rescue equipment and trench rescue assessment. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-2-2.73

Review

Personal Protective EquipmentDevelopment of a Safe CultureEquipment for Trench Rescue OperationsCalculating the Weight of an ObjectGravityMovementMechanics

RES 206-PPT-2-2.74

Review

Air Bags for Trench RescueCribbingWedgesTime of AlarmArrival at the SceneAssessment During the Emergency

1


Lesson 3-1Hazard Control and Victim Considerations

RES 206-PPT-3-1.1


Given information from discussion, handouts, and reading materials, describe hazard control and victim considerations. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-3-1.2

Overview

Hazard CategoriesHazard Control PhasesAtmospheric Monitoring for Trench RescueAction GuidelinesSpecific Monitoring MeasurementsStandard Operating GuidelinesHazard Control Using VentilationAtmospheric Monitoring Concepts

2

RES 206-PPT-3-1.3

Overview

Non-Entry Rescue and Victim Self-RescuePre-entry BriefingGaining Access to Your VictimPatient Care ConsiderationsTermination and Post-Incident Considerations

RES 206-PPT-3-1.4

Overview

Ground PadsSheetingShoringIsolation Tunnels, Shafts, and Engineered SystemsCommercial Techniques

RES 206-PPT-3-1.5

Hazard Categories

Mechanical hazards• Mechanical hazards may involved machines or

other entrapping mechanisms • Everything must be brought to “zero mechanical

state”Removing the keysLocking out electrical devicesRemoving machines from the collapse zone

3

RES 206-PPT-3-1.6

Hazard Categories

Chemical hazards• May have been unearthed during digging

operations• May have been carried into the trench by a

worker

RES 206-PPT-3-1.7

Hazard Categories

RES 206-PPT-3-1.8

Hazard Categories

Manmade hazards• Are usually the reason for the collapse• Are part of the normal work that takes

place• May be the spoil pile and equipment

location

4

RES 206-PPT-3-1.9

Hazard Categories

Electrical hazards• Should be controlled by a professional• Come in many forms

Power linesTelephone lines

• Should be clearly marked by a utility location service

RES 206-PPT-3-1.10

Hazard Categories

Water hazards (from groundwater or rain)• Build a cover for the trench• Divert rain• Dewater• Deploy an inflatable tent to cover trench

RES 206-PPT-3-1.11

Hazard Categories

Hazard markings• Red• Orange• Yellow• Green• Blue• Violet• Pink• White

5

RES 206-PPT-3-1.12

Hazard Control Phases

Follow a logical orderAddress the greatest hazard firstAddress hazards that are not readily apparentUse standard nomenclature• Hazmat

HotWarmCold

RES 206-PPT-3-1.13

RES 206-PPT-3-1.14


• Perform the following activities in the general area

StagingCuttingLogistical supportRehabVehicle parking

6

RES 206-PPT-3-1.15


• Perform the following activities in the rescue area

Air supplyPanel teamShoring personnelSafety officer

RES 206-PPT-3-1.16

Atmospheric Monitoring for Trench Rescue

Atmospheric monitoring in confined spaces is required by OSHAConfined spaces have features that are similar to the features of a trenchAtmospheric monitoring should be performed by trained personnel• Hazmat personnel• Support function personnel

RES 206-PPT-3-1.17


Monitor the atmosphere to• Detect the presence of an IDLH atmosphere• Gauge the ventilation of the trench

7

RES 206-PPT-3-1.18


RES 206-PPT-3-1.19


Consider the following when monitoring:• What is the nature of the hazard that I am

monitoring? • Are there sources of electrical interference

around?• What are the environmental site conditions

that you are operating in?• Are there gases and vapors interfering with

your monitor?

RES 206-PPT-3-1.20

Action Guidelines

Guidelines outlined in OSHA 1910.146• Indicate that you should take specific actions

when monitor readings reach certain levels• Are based on preset alarms on your

monitors that will alert when a certain level, parameter, or product is detected

8

RES 206-PPT-3-1.21

Action Guidelines

General monitoring guidelines• Rule 1 – Monitor in order

OxygenFlammability/combustibility Toxicity

RES 206-PPT-3-1.22

Action Guidelines

Rule 2 – Always monitor at multiple levels in the trench• Mixtures of gases may accumulate at different

levels depending on their vapor density • Different products have different vapor densities

Methane is lighter than air and may leave the trenchCarbon monoxide is about the same density as air and will diversify with the airHydrogen sulfide is heavier than air and will settle on the bottom of the trench

RES 206-PPT-3-1.23

Action Guidelines

Rule 3 – Know your monitor’s limitationsRule 4 – Understand the relationship between flammability and toxicityRule 5 – A substance that comes after you is much more dangerous than one that expects you to come to itRule 6 – Know your monitor’s operational parameters

9

RES 206-PPT-3-1.24

Action Guidelines

Rule 7 – Check batteries every shift Rule 8 – Zero and field calibrate your instrument in clean air• Oxygen level should read 20.9%• Flammability should read 0% of LEL• Toxicity should read 0 PPM

RES 206-PPT-3-1.25

Action Guidelines

Rule 9 – Sample from upwindRule 10 – Always assign a competent person to perform atmospheric monitoring

RES 206-PPT-3-1.26

Specific Monitoring Measurements

Oxygen• Is measured at between 0 and 25%• Is considered deficient at levels of 19.5% or

below and will cause an alarm • Is considered rich at or above levels of

23.5% and will cause an alarm • Is considered a normal concentration at

20.9%

10

RES 206-PPT-3-1.27


Flammable and combustible readings• Combustible gas indicators (CGIs) determine the

presence of flammable vapors of hydrocarbon products

• Monitors are calibrated for certain flammable gases• Tests for flammability should be conducted when it

is suspected that the trench is contaminated, to detect leaks, or when investigating any unknown material

• Any concentration at 10% of the LEL will sound an alarm

RES 206-PPT-3-1.28


Toxicity• Toxicity is measured in parts per million• Monitors have one or two toxic sensors• Alarm settings are set at

35 ppm for carbon monoxide 10 ppm for hydrogen sulfide – Time-weighted averages for an OSHA 8-

hour exposure

RES 206-PPT-3-1.29

Standard Operating Guidelines

Monitoring should be done• Before entry• Every five minutes

11

RES 206-PPT-3-1.30


RES 206-PPT-3-1.31


Monitoring should follow guidelines• Collect and record monitor readings

throughout the entry and rescue/ recovery operation

• Capture readings on the trench rescue tactical worksheet

• Report readings to the extrication officer or the operations officer on a continual basis

RES 206-PPT-3-1.32


Monitoring (continued)

• Report any fluctuations or changes in readings immediately

• Report any alarm levels immediately and take action

• Never leave the monitor unattended• Always use the hazmat team to your

advantage

12

RES 206-PPT-3-1.33

Hazard Control Using Ventilation

Ventilation• Is the first method of choice in trench

emergencies because it is fast and easily monitored

• Does not work in every situation• Is only as good as the technique used

RES 206-PPT-3-1.34

Hazard Control Using Ventilation

Ventilation (continued)

• Will not help if there is an off-gassing product in the trench

• Is dependent upon weather and environmental factors

• May require multiple fans

RES 206-PPT-3-1.35

Atmospheric Monitoring Concepts

Atmospheric Monitoring:• Read the instruction manual for your device• Practice, practice, practice• Use the most competent person for the job

13

RES 206-PPT-3-1.36

Non-Entry Rescue and Victim Self-Rescue

Are the preferred methods for trench rescueReduce risk to rescue personnelShould be considered in every incidentMay be accomplished by• Providing a ladder for victims to climb out on their

own• Supplying a harness or wristlets and lifting victims

out of the trench

May require victims to dig themselves out

RES 206-PPT-3-1.37

The Pre-Entry Briefing

Is based on a risk-benefit analysisIs the time when all rescue personnel hear the rescue planAllows the IC to think out loudAllows rescuers to openly question the plan

RES 206-PPT-3-1.38

The Pre-Entry Briefing

Must contain the basics of the rescue• The overall goal of the operation• Position assignments• Protective system design• Safety requirements• Accountability system• Emergency procedures

14

RES 206-PPT-3-1.39

Gaining Access to Your Victim

Gaining access to your victim• Is based on the type of emergency• May be difficult due to substandard

protective systems already in place

RES 206-PPT-3-1.40


Tons of dirt may have to be removed by using• Hands and buckets• Centrifugal vacuum trucks• Positive displacement vacuum trucks• Hydro Vac trucks• Rescue Vac systems

RES 206-PPT-3-1.41


• When using vacuum systems, soil reduction will likely have to be done. Air knives are frequently used to break the soil into smaller particles.

15

RES 206-PPT-3-1.42


Rule 1 – never use a mechanical device or backhoe to dig up or pull out a partially buried victimRule 2 – never attempt to pull out a partially buried victimRule 3 – Dig by hand when you get near or around the victim

RES 206-PPT-3-1.43

Patient Care Considerations

What is the victim survivability profile?Who will provide patient care?• A firefighter• An EMT• A paramedic• A physician

RES 206-PPT-3-1.44


Determine whether patient suffered injuryStart ABC assessmentAfter the primary survey has been completed, make a secondary survey and check for additional life-threatening injuries

16

RES 206-PPT-3-1.45


Prepare to package the patientFollow local and state protocolsUse a backboard as a full body splintTreat minor or other life-threatening injuries after removal

RES 206-PPT-3-1.46


Patient care involving a collapse• Try to determine the location of the head• Try to uncover the head and chest first• Remove foreign matter from the airway• Ventilate the victim• Check for breathing

RES 206-PPT-3-1.47


Patient care involving a collapse (continued)

• Protect the c-spine• Check circulatory status• Ask victim about injuries• Begin an IV if certified to do so• Apply a cardiac monitor if certified to do so

17

RES 206-PPT-3-1.48


Hypothermia (a concern even in the summer)• Keep patient as dry as possible• Use isothermal blankets• Use hot packs if necessary• Use portable lights to add heat

RES 206-PPT-3-1.49


Crush syndrome• Is a condition common to trench collapse

victims• Involves

The crushing of body tissuesThe restriction of circulationAcidosisAcidotic blood being dumped back into the bloodstream

RES 206-PPT-3-1.50


• Cardiac arrestDefibrillation– Ensure that the atmosphere is clear of

flammable gases– Dry the victim’s chestAsystole– Consider termination protocol– Contact medical control

18

RES 206-PPT-3-1.51


• Victim packaging and removalDo not dislodge shoring materialsPreplan activitiesRetrieve using a mechanical advantage system if the victim is large or the packing device is cumbersomeUse wristlets attached to an elevated platform to secure victim during diggingFind an elevated attachment point and remove victim vertically

RES 206-PPT-3-1.52

Termination and Post-Incident Considerations

Conduct a post-incident debriefingBring in fresh crews for breakdown if possibleBreak down equipment in reverse orderTake your timeWork from outside of the trenchClean all equipment Offer a critical incident stress debriefingConduct a post-incident critique

RES 206-PPT-3-1.53

Ground Pads

Are used to distribute the weight of rescuers and equipment around the lip of the trenchCome in varied sizes• 2” X 12” boards• 4’ X 8’ pieces of plywood

19

RES 206-PPT-3-1.54

Ground Pads

RES 206-PPT-3-1.55

Ground Pads

Must be correctly placed• Start at the corner of the trench

Stand on a ground padLevel the ground in front of you

• Step back and move the ground pad forward• Repeat the process of leveling the ground

and advancing the ground pads until all are in place

• Do not step off of the ground pad

RES 206-PPT-3-1.56

Sheeting

Is usually a Shorform or FinnForm panelMay have a strongback attachedRequires an almost vertical trench wallMay not always be necessaryProvides a level of comfort for the rescuerMay eliminate running debrisMay be unattached from strongback for storage

20

RES 206-PPT-3-1.57

Sheeting

Sheeting must be properly installed• Same side panel installation

Place ropes on the panel and prepare for installationPlace the panel at the lip of the trench and hold the ropes as the panel is advanced into the trenchUse ropes to slowly lower the panel into the trench and then to adjust the panel

RES 206-PPT-3-1.58

RES 206-PPT-3-1.59

21

RES 206-PPT-3-1.60

RES 206-PPT-3-1.61

Sheeting

• Opposite side panel installationPlace 4” × 4” runners to the opposite side of the trenchFlip the panel so that the strongback is pointing downAdvance the panel down the runners and position in place with a pike pole or rope

RES 206-PPT-3-1.62

22

RES 206-PPT-3-1.63

Sheeting

RES 206-PPT-3-1.64

Sheeting

Sheeting• Must be placed at the victim first• Must extend one panel to either side of the

victim

RES 206-PPT-3-1.65

Shoring

Is the component of the system that transfers forces across the trench, through the strongback, and into the opposite trench wallCompletes the protective systemProvides a safe area in which to work

23

RES 206-PPT-3-1.66

RES 206-PPT-3-1.67

Shoring

Pneumatic shores—installationConnect the air system to the shoreLower the shore using ropes at each endPosition the shoreGive the signal to shoot and holdShoot and lock the shoreToe nail the shore to the strongback– Air pressure is released and the hose

disconnected

RES 206-PPT-3-1.68

Shoring

Pneumatic shore placement• Follow manufacturers recommendations • Follow department SOGs

24

RES 206-PPT-3-1.69

Shoring

Number of shores: Shoot three shores for trenches 6 feet deep or more, regardless of soil type

RES 206-PPT-3-1.70

Shoring

• Spacing of pneumatic shores18” to 24” from the trench lip18” to 24” from the trench bottomNot more than 4’ apart

RES 206-PPT-3-1.71

Shoring

25

RES 206-PPT-3-1.72

Shoring

Timber shores• Measure, cut, and scab after placement • Install

Top shore firstMiddle shore nextBottom shore last

• Nail scabs above and below• Tighten with wedges

RES 206-PPT-3-1.73

Shoring

RES 206-PPT-3-1.74

Shoring

Wales• Are horizontal members that are used to

span openings along trench walls• May be located inside or outside of the

strongback and panel system • May be made of timber, metal, or ladders

26

RES 206-PPT-3-1.75

Shoring

• Inside wales Use in a “T” trenchLower inside the panelPlace up against the strongbackShoot the shores

RES 206-PPT-3-1.76

RES 206-PPT-3-1.77

Shoring

• Outside walesPlace against the trench wall before placement of panelsUse to span openings created by a slough of the trench wallBackfill after installation of the wales and panels but before the shores are shot

27

RES 206-PPT-3-1.78

RES 206-PPT-3-1.79

Shoring

Supplemental sheeting and shoring• Is necessary to fill voids• Is additional shoring

RES 206-PPT-3-1.80

Shoring

28

RES 206-PPT-3-1.81

Isolation Tunnels, Shafts, andEngineered Systems

Isolation vessels• Are cylinder objects• Are placed over the victim• Are strongest vertically• Are weakest horizontally• Allow the victim to be dug out• May take time to place• May be the victim’s only chance

RES 206-PPT-3-1.82

RES 206-PPT-3-1.83

Isolation Tunnels, Shafts, andEngineered Systems

Engineered Systems—designed by engineers to address the worst type of soil• Each 4’ × 8’ piece of sheeting has three

strongbacks• Strongbacks are toe nailed to sheeting and

held in place using 6 × 6-inch wales• Shoring is shot where the wale crosses the

center of each strongbackSystem uses many contact points

29

RES 206-PPT-3-1.84

Commercial Techniques

Consider using commercial techniques and professional help if• The trench is deeper than 15’• There has been a massive cave-in• Workers are trapped in running debris• Environmental conditions prohibit the rescue

effort

RES 206-PPT-3-1.85


Commercial techniques are based on certain factors• Adjacent structures• Existing hazards• Soil type• Water profile and hydraulic table• Depth and width of the trench

RES 206-PPT-3-1.86


Commercial techniques may be described as• Sloping• Trench box• Rabbit box• Soldier pile and lag shoring• Sheet piling shoring• Modular shoring

30

RES 206-PPT-3-1.87


Commercial techniques—sloping and benching systems• Sloping

Decreases the angle of a wall to prevent collapseHelps to prevent active soil movementCreates a safe openingShould be at least 1.5’ horizontal to 1’vertical

RES 206-PPT-3-1.88

RES 206-PPT-3-1.89


• BenchingIs similar to cutting stepsMust follow parameters

31

RES 206-PPT-3-1.90


RES 206-PPT-3-1.91


Support, shield, and other systems• A trench box or shield

Is designed to be moved along the trench with an excavatorAllows walls to be cut at steeper anglesRequires less backfillIs difficult to use around existing utilities

RES 206-PPT-3-1.92

32

RES 206-PPT-3-1.93


• Soldier pile and sheet pile (fixed shoring systems)

Sheet piles can be cantilevered, braced, or tied back to provide ground supportPiles can be pushed into the ground using uprights made of steel plates or timberPiling is installed by– Pushing it in with a backhoe– Drilling a hole to fit the pile– Using an impact, vibrating, or hydraulic

hammer

RES 206-PPT-3-1.94

RES 206-PPT-3-1.95


Modular aluminum or steel shoring• May come in fixed sizes• May be adjustable• May come in various shapes and

configurations

33

RES 206-PPT-3-1.96

RES 206-PPT-3-1.97


Given information from discussion, handouts, and reading materials, describe hazard control and victim considerations. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-3-1.98

Overview

Hazard CategoriesHazard Control PhasesAtmospheric Monitoring for Trench RescueAction GuidelinesSpecific Monitoring MeasurementsStandard Operating GuidelinesHazard Control Using VentilationAtmospheric Monitoring Concepts

34

RES 206-PPT-3-1.99

Overview

Non-Entry Rescue and Victim Self-RescuePre-entry BriefingGaining Access to Your VictimPatient Care ConsiderationsTermination and Post-Incident Considerations

RES 206-PPT-3-1.100

Overview

Ground PadsSheetingShoringIsolation Tunnels, Shafts, and Engineered SystemsCommercial Techniques

1


Lesson 3-2Protective Systems and Techniques

RES 206-PPT-3-2.1


Given information from discussion, handouts, and reading materials, describe protective systems and techniques. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-3-2.2

Overview

Generic Steps for all Trench TypesStraight-Wall TrenchTimber ShoresPneumatic ShoresOutside Wales

2

RES 206-PPT-3-2.3

Overview

Inside WalesThe T-TrenchThe L-TrenchThe Deep Wall Trench

RES 206-PPT-3-2.4

Generic Steps for all Trench Types

Establish an Incident Command SystemProvide Hazard ControlBegin air monitoring operationsProvide ventilationInstall ground pads

RES 206-PPT-3-2.5

Generic Steps for all Trench Types

Provide ladder accessProvide a preoperational briefingBegin documentationProvide a post-incident critique

3

RES 206-PPT-3-2.6

Straight-Wall Trenches

Require a minimum of three sets of panels• One set protecting the victim• A set on each side of the initial set

RES 206-PPT-3-2.7


RES 206-PPT-3-2.8


Procedure• Using either the same side or opposite side

panel set, place first set of panels directly over the victim

• Create a safe zone around the victim

4

RES 206-PPT-3-2.9

Timber Shores

Are a minimum or 4” × 6” lumberAre set from the top down

RES 206-PPT-3-2.10

Timber Shores

RES 206-PPT-3-2.11

Timber Shores

Procedure• Work from a ladder• Never be more than waist deep• Cut shores ½” longer than necessary• Prenail the bottom scabs• Apply 2” × 4” rails to the strongback

5

RES 206-PPT-3-2.12

RES 206-PPT-3-2.13

Timber Shores

Procedure (continued)

• Install the top shore at between 12” and 18”of the top lip

• Add middle shore• Add bottom shore• Begin digging operation in protected area

RES 206-PPT-3-2.14

6

RES 206-PPT-3-2.15

Timber Shores


• Add next set of panelsMiddle shoreBottom shoreTop shore

• Ensure all shores are tight• Ensure all shores are wedged and scabbed

RES 206-PPT-3-2.16

Timber Shores

RES 206-PPT-3-2.17

7

RES 206-PPT-3-2.18

Pneumatic Shores

May be installed from outside of the trench• Should be lowered into place• Should be activated remotely

RES 206-PPT-3-2.19

Pneumatic Shores

RES 206-PPT-3-2.20

Pneumatic Shores

Follow manufacturer’s guidelines and SOGs • Work may begin after first protected area is in place

Begin the rescue effort or work from within the safe area of the first set of panels to set the outside panels

8

RES 206-PPT-3-2.21

RES 206-PPT-3-2.22

Outside Wales

Use on a single-wall slough Procedure• Place pickets to hold wales• Lower and tie off wales• Apply panels to protect the victim• Fill voids• Set panels• Fill existing voids

RES 206-PPT-3-2.23

Outside WalesOutside wales are used in systems where a single-wall slough has occurred

9

RES 206-PPT-3-2.24

Inside Wales

Are used to span a set of panelsAre used to make room for digging and equipmentAre the preferred technique in recoveries requiring a lot of digging

RES 206-PPT-3-2.25

Inside Wales

RES 206-PPT-3-2.26

Inside Wales

Procedure• Secure wales to ropes and place in the bottom of the

trench• Set all three sets of panels• Tack a board to the strongbacks to hold them together• Install middle shores on the outside panels• Lift and place the bottom wales• Install shores on the bottom wales• Place the top wales and secure with shores• Continue rescue or recovery operations

10

RES 206-PPT-3-2.27

The T-Trench

Is a very unstable trenchRequires• The quick capture of the corners• The use of inside wales• A minimum of seven panels

RES 206-PPT-3-2.28

The T-Trench

RES 206-PPT-3-2.29

The T-Trench

Procedure• Set two panels at the top of the T’s leg• Attach ropes to the bottom wale and place in

the bottom of the trench• Place the remaining five panels• Shoot the middle shores on the top of the T

with full pressure

11

RES 206-PPT-3-2.30

The T-Trench


• Raise and hold the bottom wale into position and install shores

• Lower and shore the top wale• Reshoot the original three shores and

check all shores to ensure that they are solid

RES 206-PPT-3-2.31

RES 206-PPT-3-2.32

12

RES 206-PPT-3-2.33

RES 206-PPT-3-2.34

RES 206-PPT-3-2.35

13

RES 206-PPT-3-2.36

RES 206-PPT-3-2.37

RES 206-PPT-3-2.38

The L-Trench

Is two trenches that intersect at the ends and form a right angleCreates a difficult rescue scenario

14

RES 206-PPT-3-2.39

The L-Trench

Procedure• Place wales in the bottom of the trench

secured to ropes• Set the first panels at the inside L corners

and hold in place with pickets and shoot with 50 to 75 lbs

• Use a thrust block in the outside corner for shooting shores

• Toe nail thrust blocks to strongbacks

RES 206-PPT-3-2.40

The L-Trench


• Install kick plates on the outside panels• Install outside panels• Position and tie off the bottom wale• Use a corner block in the outside corner at

the wales• Secure the corner block in place• Complete the trench

RES 206-PPT-3-2.41

15

RES 206-PPT-3-2.42

The L-Trench

RES 206-PPT-3-2.43

RES 206-PPT-3-2.44

16

RES 206-PPT-3-2.45

RES 206-PPT-3-2.46

RES 206-PPT-3-2.47

17

RES 206-PPT-3-2.48

RES 206-PPT-3-2.49

RES 206-PPT-3-2.50

18

RES 206-PPT-3-2.51

The Deep Wall Trench

Is deeper than 10’ but not deeper than 15’Is a much more complex trenchIs capable of creating forces greater than rescue equipment can withstandMay require commercial techniques

RES 206-PPT-3-2.52


Procedure• Set ground pads while wearing fall

protection• Set pickets to hold panels and wales in

place• Set panels in place

RES 206-PPT-3-2.53



• Hold panels with ropes and pickets• Set shores in the top horizontal plates to

secure them• Install shores on wales and strongbacks

working from the top to the bottom of the trench

• Complete the trench

19

RES 206-PPT-3-2.54

RES 206-PPT-3-2.55

RES 206-PPT-3-2.56

20

RES 206-PPT-3-2.57

RES 206-PPT-3-2.58

RES 206-PPT-3-2.59

21

RES 206-PPT-3-2.60

RES 206-PPT-3-2.61


In trenches deeper than 15’• Call an excavation contractor• Consult a registered engineer• Consider benching or sloping

RES 206-PPT-3-2.62


Given information from discussion, handouts, and reading materials, describe protective systems and techniques. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

22

RES 206-PPT-3-2.63

Review

Generic Steps for all Trench TypesStraight-Wall TrenchTimber ShoresPneumatic ShoresOutside WalesInside WalesThe T-TrenchThe L-TrenchThe Deep Wall Trench

1


Lesson 4-2Incident Action Plan

RES 206-PPT-4-2.1


Given information from discussion, handouts, and reading materials, describe the trench rescue incident action plan. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-4-2.2

Overview

Incident Action PlanCommand StructureKnow Your GroupSite-Specific Safety ConcernsCommunications

2

RES 206-PPT-4-2.3

Overview

Personal Protective EquipmentReal EmergencyDirections to Trench LocationDebriefing

RES 206-PPT-4-2.4

Incident Action Plan

OSHA Incident Action PlanAHJ Incident Action Plan

RES 206-PPT-4-2.5

Command Structure

IC—primary instructorOperations—secondary instructorSafety officer—tertiary instructorAll other positions as assigned by the IC

3

RES 206-PPT-4-2.6

Know Your Group

Divide into three equally sized groupsRemember your group number

Groups may be reassigned later if necessary

RES 206-PPT-4-2.7

Site Specific Safety Concerns

Known hazardsCommon hazardsFreelancingHorseplayHydration policy

RES 206-PPT-4-2.8

Communications

Advising the 911 center of training in a live trenchRadio communicationsSpecialized communicationsUsing “FOR REAL” in the event of a real emergency

4

RES 206-PPT-4-2.9


HelmetEye protectionEar protectionLong sleevesGlovesPants/jumpsuit

RES 206-PPT-4-2.10


Knee padsFoot protectionJacket/sweatshirtWater bottleOther

RES 206-PPT-4-2.11

Real Emergency

Medical/injury not in the trench will be handled by standby crew

5

RES 206-PPT-4-2.12

Real Emergency

Trench collapse/incident requiring rescue• IC will conduct a scene size-up• IC will notify 911 communications of an

incident “FOR REAL”• IC will manage the incident • Students will follow directives of IC

RES 206-PPT-4-2.13

Directions to Trench Location

RES 206-PPT-4-2.14

Debriefing

Concluding thoughts Questions

6

RES 206-PPT-4-2.15


Given information from discussion, handouts, and reading materials, describe the trench rescue incident action plan. The student will perform to a written test accuracy of at least 70% and successfully complete the skills on a skills check-off sheet.

RES 206-PPT-4-2.16

Review

Incident Action PlanCommand StructureKnow Your GroupSite-Specific Safety ConcernsCommunications

RES 206-PPT-4-2.17

Review

Personal Protective EquipmentReal EmergencyDirections to Trench LocationDebriefing

trench rescue operations - maryland fire and rescue institute

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