Trench Rescue I

1
Trench Rescue I

• presented by the
• Office of the State Fire Marshall of Illinois

2
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

3
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

4
Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

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Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

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OSFM Technical Rescue Specialist Certifications
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Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

8
Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

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Definition of a trench

• OSHA defines a trench as an excavation which is
  deeper and longer than it is wide and is less
  than 15 feet wide at the bottom.

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Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

11
Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

12
Trenching operations

• OSHA protection requirements are often ignored
• Contractors are often family businesses

13
Trenching operations

• OSHA protection requirements are often ignored
• Contractors are often family businesses

14
Trenching operations

• OSHA protection requirements are often ignored
• Ignorance/complacency of risks
• Economic factors
• Contractors are often family businesses

15
Trenching operations

• OSHA protection requirements are often ignored
• Ignorance/complacency of risks
• Inexperienced contractor
• Experienced contractor with no history of
  problems
• Complaints of inconvenience from workers
• Economic factors
• Contractors are often family businesses

16
Trenching operations

• OSHA protection requirements are often ignored
• Ignorance/complacency of risks
• Inexperienced contractor
• Experienced contractor with no history of
  problems
• Complaints of inconvenience from workers
• Economic factors
• Contractors are often family businesses

17
Trenching operations

• OSHA protection requirements are often ignored
• Ignorance/complacency of risks
• Inexperienced contractor
• Experienced contractor with no history of
  problems
• Complaints of inconvenience from workers
• Economic factors
• Cost of equipment
• Labor cost to install equipment
• Elimination of protection equipment to be awarded
  low bid
• Contractors are often family businesses

18
Trenching operations

• OSHA protection requirements are often ignored
• Ignorance/complacency of risks
• Inexperienced contractor
• Experienced contractor with no history of
  problems
• Complaints of inconvenience from workers
• Economic factors
• Cost of equipment
• Labor cost to install equipment
• Elimination of protection equipment to be awarded
  low bid
• Contractors are often family businesses

19
Trenching operations

• OSHA protection requirements are often ignored
• Ignorance/complacency of risks
• Inexperienced contractor
• Experienced contractor with no history of
  problems
• Complaints of inconvenience from workers
• Economic factors
• Cost of equipment
• Labor cost to install equipment
• Elimination of protection equipment to be awarded
  low bid
• Contractors are often family businesses
• Results in extremely emotional rescue scenes

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Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

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Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

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Trench accidents and statistics

• Trenching operations take place on a daily basis
  in almost all jurisdictions

• Over 100 workers are killed annually in trench
  accidents
• As much as 65 of those killed in trench
  collapses are rescuers

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Introduction

• OSFM technical rescue certifications
• Definition of a trench
• Trenching operations
• Trench accidents and statistics

24
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

25
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

26
Trench Rescue Hazards

• Hazards are not obvious

• Trenches dont appear dangerous
• Understanding the hazards requires training
• By-standers, co-workers, and even fire officers
  will not understand the inaction of trained
  rescuers until the trench is properly protected

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• Depends upon the type of collapse
• Responsible for most deaths in trench collapses
• Usually occurs just in time to trap a would-be
  rescuer

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Types of collapses
Slough-in
Sidewall-in Shear-in
Spoil-in
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How rescuers become victims
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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• 90-145 lbs per cubic foot
• Averages 100 lbs per cubic foot
• Average collapse is 1.5 cubic yards (about 4000
  lbs)
• A victim under 2 feet of soil will be under about
  3000 lbs of soil, approximately 1000 lbs of which
  will be on his chest

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Trenches will often collapse within 1/10th of a
  second
• There is often little or no warning of collapse
• Spalling of soil or widening fissures are signs
  of eminent collapse
• Escape is unlikely during a collapse
• Victims are often frozen in place

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Trench rescues will often require in excess of
  4-6 hours
• The trench will become more unstable with time

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• The operator is likely to inflict serious or
  fatal injury to the victim
• The weight and vibration from the backhoe is
  likely to accelerate the occurance of a fatal
  secondary collapse
• Backhoes are an acceptable device for recovery
  operations

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• Trenches exceed OSHA limits

• OSHA provides quidelines for trenches up to 15
  feet wide and 20 feet deep. Custom engineering
  is required beyond those limits
• A contractor who did not provide proper
  protection for his employees is likely to not
  understand the limits

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• Trenches exceed OSHA limits

• Buried utilities

• Many more injuries and deaths in trenches are
  caused by contact with buried utilities than are
  from collapse
• Rescuers are not immune to this danger

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Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• Trenches exceed OSHA limits

• Buried utilities

• Impact or entrapment from falling objects

• This is the leading cause of death and injury in
  trenches
• Rescuers must control this hazard prior to entry

37
Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• Trenches exceed OSHA limits

• Buried utilities

• Impact or entrapment from falling objects

• Uncollapsed unprotected trenches still dangerous

• Rescuers must be wary of apparently simple
  rescues from uncollapsed trenches

38
Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• Trenches exceed OSHA limits

• Buried utilities

• Impact or entrapment from falling objects

• Uncollapsed unprotected trenches still dangerous

• Inadequate equipment for shoring

• Untrained rescuers may be lulled into false
  security by using inadequate shoring materials
  such as backboards
• Shoring systems require extremely strong materials

39
Trench Rescue Hazards

• Hazards are not obvious

• Secondary collapse

• The weight of dirt

• The speed that dirt can move

• Rescues are usually long-term operations

• Backhoes are not safe for victim rescue

• Trenches exceed OSHA limits

• Buried utilities

• Impact or entrapment from falling objects

• Uncollapsed unprotected trenches still dangerous

• Inadequate equipment for shoring

• Possible legal liabilities for fire officers

• Fire officers may face both criminal and civil
  charges for injuries to their personnel resulting
  from ignoring OSHA regulations

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Trench Rescue Hazards

• Hazards are not obvious
• Secondary collapse
• The weight of dirt
• The speed that dirt can move
• Rescues are usually long-term operations
• Backhoes are not safe for victim rescue
• Trenches exceed OSHA limits
• Buried utilities
• Impact or entrapment from falling equipment
• Uncollapsed unprotected trenches still dangerous
• Inadequate equipment for shoring
• Possible legal liabilities for fire officers

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Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

42
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

43
OSHA Regulations

• Applicable regulations

• 29 CFR 1926 Subpart P (Excavations)
• Applies to public sector and to Federal employees
• Illinois has adopted 1926 by reference in the
  Illinois Register Part 350 Section 350.280
• Applies to municipal, fire district, and State
  employees

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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Sloping
• Shoring
• Shielding

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Methods of providing worker protection
Sloping
Shoring
Shielding
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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Stable rock
• Class-A
• Cohesive soils
• Clumps which are difficult to break apart
• Class-B
• Some cohesiveness
• Clumps which are easily broken or molded
• Class-C
• Loose soils
• Wet soils

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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• OSHA requires at least one visual one manual
  test
• Visual tests
• Observe spoil pile and its clumping behaviour
• Observe sides and lip of trench for layers and
  tension cracks
• Watch for seeping water
• Determine likelyhood of previously disturbed soil
• Manual tests
• Thumb penetration test
• Pocket penetrometer
• Shearvane

48
OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C

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Dangers of wet soils
Standing water undermines trench walls
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Dangers of wet soils
Water table
Seeping water causes the soil to shift
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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C

52
OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C
• Soil classification must be lowered if
• Layered soils slope toward the trench

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Sloped, layered soils
Top soil
Sand
Clay
Trench must be classified to the worst soil
layer If layers slope toward the trench, class
must also be dropped
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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C
• Soil classification must be lowered if
• Layered soils slope toward the trench

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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C
• Soil classification must be lowered if
• Layered soils slope toward the trench
• Fissures are present

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Fissured soils
Top view
Side view
Soil classification must be lowered one level
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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C
• Soil classification must be lowered if
• Layered soils slope toward the trench
• Fissures are present

58
OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests

• Adjustments to soil classification

• Wet soils are always Class-C
• Soil classification must be lowered if
• Layered soils slope toward the trench
• Fissures are present

• Soil has been previously disturbed
• Soil is subject to vibration
• Trench collapse rescues must be no better than
  Class-B
• Many rescue teams will operate as if all are
  Class-C

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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests
• Adjustments to soil classification

• Other factors which will effect trench stability

• Exposure to elements
• Long term trench is open gt24 hours
• Superimposed loads

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Superimposed loads
OSHA requires all superimposed loads to be no
closer than 2 feet from trench
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Superimposed loads
Spoil piles are exceptionally dangerous
superimposed loads
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Superimposed loads
2
OSHA requires the spoil pile to be at least 2
from trench Whenever possible, move the spoil
pile futher back to increase work area, expose
fissures, and reduce possible impact from spoil
weight
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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests
• Adjustments to soil classification

• Other factors which will effect trench stability

• Exposure to elements
• Long term trench is open gt24 hours
• Superimposed loads

• Underground utilities
• May require shoring of their own
• Surface encumbrances
• Will require a registered professional engineer
• Water removal
• Standing water must be removed

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OSHA Regulations

• Applicable reguations

• Methods of providing worker protection

• Soil classifications

• Soil classification tests
• Adjustments to soil classification
• Other factors which will effect trench stability

• Additional regulations for worker safety

• Escape routes
• No more than 25 ft. travel distance
• If using a ladder, it must extend a few feet
  above the trench and be secured
• Air quality monitoring
• Personal protective equipment
• Helmet, boots, reflective vests, eye
  protection...
• Impact protection
• Stop logs, warning devices, spotters

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Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

66
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations

67
Protective systems

• Sloping

• Must slope to the angle of repose
• Angle depends on the soil classification

68
Sloping a trench
4
8
12
8
8
8
Class-A Class-B
Class-C
Slope angle is determined by soil classification
69
Protective systems

• Sloping

• Must slope to the angle of repose
• Angle depends on the soil classification

• May incorporate steps or benches
• May be used in combination with shielding or
  shoring

70
Sloping a trench
Benching a trench
Using sloping with shielding/shoring
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Protective systems

• Sloping

• Must slope to the angle of repose
• Angle depends on the soil classification
• May incorporate steps or benches
• May be used in combination with shielding or
  shoring

• Impractical in the midwest due to width of opening

72
Sloping a trench
23
10
10
10
3
Sloping is often impractical
73
Protective systems

• Sloping

• Shielding

• Strong metal boxes which can hold back the force
  of moving soil
• Typically assembled at the work site and
  maneuvered into position with a backhoe

74
Shielding
Typical trench shield
75
Protective systems

• Sloping

• Shielding

• Strong metal boxes which can hold back the force
  of moving soil
• Typically assembled at the work site and
  maneuvered into position with a backhoe

• Boxes must be designed for the trench dimensions
  and the type of soil they are to be used in
• Worker must stay within the box to be protected
• Box must be positioned correctly
• Must extend a few inches above the trench lip
• Must be no further than 2 ft. off bottom

76
Shielding
2 max.
Proper positioning of a trench box
77
Shielding
Dangers of improper placement of a trench box
78
Protective systems

• Sloping
• Shielding

• Shoring

• A support system which is only strong enough to
  stop dirt from starting to move
• Works by exerting pressure and resistance into
  the trench walls creating arches of protection

79
Shoring
Shoring works by creating arches of protection
80
Protective systems

• Sloping
• Shielding

• Shoring

• A support system which is only strong enough to
  stop dirt from starting to move
• Works by exerting pressure and resistance into
  the trench walls creating arches of protection

• Shoring system components

• Simple shoring system
• Shoring system with wales
• Sheeting systems

81
Shoring
Upright
Crossbrace
Simple shoring system
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Shoring
Upright
Crossbrace
Wale
Shoring system with wales Allows for additional
uprights or sheeting as required
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Shoring
Close sheeting
84
Shoring
Tight sheeting
85
Shoring
Plywood sheeting Not considered structural
unless it is specified as part of an engineered
system OSHA requires 1 1/8 soft plywood or 3/4
14-ply finland form
86
Protective systems

• Sloping
• Shielding

• Shoring

• A support system which is only strong enough to
  stop dirt from starting to move
• Works by exerting pressure and resistance into
  the trench walls creating arches of protection

• Shoring system components

• Simple shoring system
• Shoring system with wales
• Sheeting systems

• Types of shoring systems

• Timber
• Screwjack
• Pneumatic
• Hydraulic

87
Shoring

• OSHA has charts for construction
• Requires numerous large timbers
• Wood must be Douglas Fir or
  mixed oak
• Difficult to find and store
• Must be custom cut at scene
• Requires installer to enter trench
• Pressurized with wooden wedges

Timber shoring
88
Shoring
4 x 6 x 14 uprights
8 x 8 x 14 walers
2 x 4 wedges
6 x 6 x 4 crossbraces
2 x 2 blocks
Timbers required for 12 length of 4 wide, 10
deep trench in Class-B soil
89
Shoring

• Difficult to find engineering tables
• Are often equipped with inadequate pipe
• Must be custom cut at scene
• Requires installer to enter trench
• Pressurized by screwing jack out
• Must have feet installed
• Must not expose more than 1/2 of the screw

Screwjack shoring
90
Shoring

• Most popular rescue strut
• Requires purchase of multiple lengths for rescue
• Requires installer to enter trench
• Pressurized by air pressure, then locked into
  place
• Requires timber components for uprights and
  walers
• Manufacturer has engineering data to help
  eliminate timber requirements
• Airshore Paratech manufacturers

Pneumatic shoring
91
Shoring

• OSHA has design charts
• Requires purchase of multiple lengths for rescue
• Bulky to store
• Pressurized by hydraulic hand pump
• Only system which does not require the installer
  to enter the trench
• Difficult to use on uneven walls
• Allows greater depths without walers

Hydraulic shoring
92
Protective systems

• Sloping
• Shielding

• Shoring

• A support system which is only strong enough to
  stop dirt from starting to move
• Works by exerting pressure and resistance into
  the trench walls creating arches of protection

• Shoring system components

• Simple shoring system
• Shoring system with wales
• Sheeting systems

• Types of shoring systems

• Timber
• Screjack
• Pneumatic
• Hydraulic

93
Course Content

• Introduction
• Trench Rescue Hazards
• OSHA Regulations
• Protective Systems
• Shoring System Design
• Rescue Shoring
• Trench Rescue Operations