Trench Awareness presented by the… Office of the State Fire Marshall of Illinois

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

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

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

OSFM Technical Rescue Specialist Certifications

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

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

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.

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

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

Trenching operations u OSHA protection requirements are often ignored u Contractors are often family businesses

Trenching operations u OSHA protection requirements are often ignored u Contractors are often family businesses

Trenching operations u OSHA protection requirements are often ignored F Ignorance/complacency of risks F Economic factors u Contractors are often family businesses

Trenching operations u OSHA protection requirements are often ignored F Ignorance/complacency of risks Inexperienced contractorInexperienced contractor Experienced contractor with no history of problemsExperienced contractor with no history of problems Complaints of inconvenience from workersComplaints of inconvenience from workers F Economic factors u Contractors are often family businesses

Trenching operations u OSHA protection requirements are often ignored F Ignorance/complacency of risks Inexperienced contractorInexperienced contractor Experienced contractor with no history of problemsExperienced contractor with no history of problems Complaints of inconvenience from workersComplaints of inconvenience from workers F Economic factors u Contractors are often family businesses

Trenching operations u OSHA protection requirements are often ignored F Ignorance/complacency of risks Inexperienced contractorInexperienced contractor Experienced contractor with no history of problemsExperienced contractor with no history of problems Complaints of inconvenience from workersComplaints of inconvenience from workers F Economic factors Cost of equipmentCost of equipment Labor cost to install equipmentLabor cost to install equipment Elimination of protection equipment to be awarded low bidElimination of protection equipment to be awarded low bid u Contractors are often family businesses

Trenching operations u OSHA protection requirements are often ignored F Ignorance/complacency of risks Inexperienced contractorInexperienced contractor Experienced contractor with no history of problemsExperienced contractor with no history of problems Complaints of inconvenience from workersComplaints of inconvenience from workers F Economic factors Cost of equipmentCost of equipment Labor cost to install equipmentLabor cost to install equipment Elimination of protection equipment to be awarded low bidElimination of protection equipment to be awarded low bid u Contractors are often family businesses

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

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

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

Trench accidents and statistics u Trenching operations take place on a daily basis in almost all jurisdictions u Over 100 workers are killed annually in trench accidents u As much as 65% of those killed in trench collapses are rescuers

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

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

Trench Rescue Hazards n Hazards are not obvious u Trenches don’t appear dangerous u Understanding the hazards requires training u By-standers, co-workers, and even fire officers will not understand the inaction of trained rescuers until the trench is properly protected

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse u Depends upon the type of collapse u Responsible for most deaths in trench collapses u Usually occurs just in time to trap a would-be rescuer

Types of collapses Slough-in Sidewall-in Shear-in Spoil-in

How rescuers become victims

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt u lbs. per cubic foot u Averages 100 lbs. per cubic foot u Average collapse is 1.5 cubic yards (about 4000 lbs.) u 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

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move u Trenches will often collapse within 1/10th of a second u There is often little or no warning of collapse F Spalling of soil or widening fissures are signs of eminent collapse u Escape is unlikely during a collapse F Victims are often “frozen” in place

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations u Trench rescues will often require in excess of 4-6 hours u The trench will become more unstable with time

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Backhoes are not safe for victim rescue u The operator is likely to inflict serious or fatal injury to the victim u The weight and vibration from the backhoe is likely to accelerate the occurrence of a fatal secondary collapse u Backhoes are an acceptable device for recovery operations

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Trenches exceed OSHA limits n Backhoes are not safe for victim rescue u OSHA provides guidelines for trenches up to 15 feet wide and 20 feet deep. Custom engineering is required beyond those limits u A contractor who did not provide proper protection for his employees is likely to not understand the limits

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Trenches exceed OSHA limits n Backhoes are not safe for victim rescue n Buried utilities u Many more injuries and deaths in trenches are caused by contact with buried utilities than are from collapse u Rescuers are not immune to this danger

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Trenches exceed OSHA limits n Backhoes are not safe for victim rescue n Buried utilities n Impact or entrapment from falling objects u This is the leading cause of death and injury in trenches u Rescuers must control this hazard prior to entry

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Trenches exceed OSHA limits n Backhoes are not safe for victim rescue n Buried utilities n Impact or entrapment from falling objects n Uncollapsed unprotected trenches still dangerous u Rescuers must be wary of apparently simple rescues from uncollapsed trenches

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Trenches exceed OSHA limits n Backhoes are not safe for victim rescue n Buried utilities n Impact or entrapment from falling objects n Uncollapsed unprotected trenches still dangerous n Inadequate equipment for shoring u Untrained rescuers may be lulled into false security by using inadequate shoring materials such as backboards u Shoring systems require extremely strong materials

Trench Rescue Hazards n Hazards are not obvious n Secondary collapse n The weight of dirt n The speed that dirt can move n Rescues are usually long-term operations n Trenches exceed OSHA limits n Backhoes are not safe for victim rescue n Buried utilities n Impact or entrapment from falling objects n Uncollapsed unprotected trenches still dangerous n Inadequate equipment for shoring n Possible legal liabilities for fire officers u Fire officers may face both criminal and civil charges for injuries to their personnel resulting from ignoring OSHA regulations

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

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

OSHA Regulations n Applicable regulations u 29 CFR 1926 Subpart P (Excavations) F Applies to public sector and to Federal employees u Illinois has adopted 1926 by reference in the Illinois Register Part 350 Section F Applies to municipal, fire district, and State employees

OSHA Regulations n Applicable regulations n Methods of providing worker protection u Sloping u Shoring u Shielding

Methods of providing worker protection Sloping Shoring Shielding

OSHA Regulations n Applicable regulations n Soil classifications u Stable rock u Class-A F Cohesive soils F Clumps which are difficult to break apart u Class-B F Some cohesiveness F Clumps which are easily broken or molded u Class-C F Loose soils F Wet soils n Methods of providing worker protection

OSHA Regulations n Applicable regulations n Soil classification tests u OSHA requires at least one visual & one manual test F Visual tests Observe spoil pile and its clumping behaviorObserve spoil pile and its clumping behavior Observe sides and lip of trench for layers and tension cracksObserve sides and lip of trench for layers and tension cracks Watch for seeping waterWatch for seeping water Determine likelihood of previously disturbed soilDetermine likelihood of previously disturbed soil F Manual tests Thumb penetration testThumb penetration test Pocket penetrometerPocket penetrometer ShearvaneShearvane n Methods of providing worker protection n Soil classifications

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification u Wet soils are always Class-C n Methods of providing worker protection n Soil classifications

Dangers of wet soils Standing water undermines trench walls

Dangers of wet soils Seeping water causes the soil to shift Water table

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification u Wet soils are always Class-C n Methods of providing worker protection n Soil classifications

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification u Wet soils are always Class-C u Soil classification must be lowered if: F Layered soils slope toward the trench n Methods of providing worker protection n Soil classifications

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

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification u Wet soils are always Class-C u Soil classification must be lowered if: F Layered soils slope toward the trench n Methods of providing worker protection n Soil classifications

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification u Wet soils are always Class-C u Soil classification must be lowered if: F Layered soils slope toward the trench F Fissures are present n Methods of providing worker protection n Soil classifications

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

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification u Wet soils are always Class-C u Soil classification must be lowered if: F Layered soils slope toward the trench F Fissures are present n Methods of providing worker protection n Soil classifications

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification F Soil has been previously disturbed F Soil is subject to vibration u Trench collapse rescues must be no better than Class-B u Many rescue teams will operate as if all are Class-C n Methods of providing worker protection n Soil classifications u Wet soils are always Class-C u Soil classification must be lowered if: F Layered soils slope toward the trench F Fissures are present

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification n Other factors which will effect trench stability u Exposure to elements F Long term trench is open >24 hours u Superimposed loads n Methods of providing worker protection n Soil classifications

Superimposed loads OSHA requires all superimposed loads to be no closer than 2 feet from trench

Superimposed loads Spoil piles are exceptionally dangerous superimposed loads

Superimposed loads OSHA requires the spoil pile to be at least 2’ from trench Whenever possible, move the spoil pile further back to increase work area, expose fissures, and reduce possible impact from spoil weight 2’

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification n Other factors which will effect trench stability u Underground utilities F May require shoring of their own u Surface encumbrances F Will require a registered professional engineer u Water removal F Standing water must be removed n Methods of providing worker protection n Soil classifications u Exposure to elements F Long term trench is open >24 hours u Superimposed loads

OSHA Regulations n Applicable regulations n Soil classification tests n Adjustments to soil classification n Other factors which will effect trench stability n Additional regulations for worker safety u Escape routes F No more than 25 ft. travel distance F If using a ladder, it must extend a few feet above the trench and be secured u Air quality monitoring u Personal protective equipment F Helmet, boots, reflective vests, eye protection... u Impact protection F Stop logs, warning devices, spotters n Methods of providing worker protection n Soil classifications

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations

Protective systems n Sloping u Must slope to the angle of repose u Angle depends on the soil classification

Sloping a trench Slope angle is determined by soil classification 4’ 8’ 12’ Class-A Class-B Class-C

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

Sloping a trench Benching a trench Using sloping with shielding/shoring

Protective systems n Sloping u Must slope to the angle of repose u Angle depends on the soil classification u May incorporate steps or benches u May be used in combination with shielding or shoring u Impractical in the Midwest due to width of opening

Sloping a trench 23’ 10’ 3’ 10’ Sloping is often impractical

Protective systems n Sloping n Shielding u Strong metal boxes which can hold back the force of moving soil u Typically assembled at the work site and maneuvered into position with a backhoe

Shielding Typical trench shield

Protective systems n Sloping n Shielding u Strong metal boxes which can hold back the force of moving soil u Typically assembled at the work site and maneuvered into position with a backhoe u Boxes must be designed for the trench dimensions and the type of soil they are to be used in u Worker must stay within the box to be protected u Box must be positioned correctly: F Must extend a few inches above the trench lip F Must be no further than 2 ft. off bottom

Shielding Proper positioning of a trench box 2’ max.

Shielding Dangers of improper placement of a trench box

Protective systems n Sloping n Shielding n Shoring u A support system which is only strong enough to stop dirt from starting to move u Works by exerting pressure and resistance into the trench walls creating arches of protection

Shoring Shoring works by creating arches of protection

Protective systems n Sloping n Shielding n Shoring u A support system which is only strong enough to stop dirt from starting to move u Works by exerting pressure and resistance into the trench walls creating arches of protection u Shoring system components F Simple shoring system F Shoring system with wales F Sheeting systems

Shoring Simple shoring system Upright Crossbrace

Shoring Shoring system with wales Allows for additional uprights or sheeting as required Upright Crossbrace Wale

Shoring Close sheeting

Shoring Tight sheeting

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

Protective systems n Sloping n Shielding n Shoring u A support system which is only strong enough to stop dirt from starting to move u Works by exerting pressure and resistance into the trench walls creating arches of protection u Shoring system components F Simple shoring system F Shoring system with wales F Sheeting systems u Types of shoring systems F Timber F Screwjack F Pneumatic F Hydraulic

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

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

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

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

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

Protective systems n Sloping n Shielding n Shoring u A support system which is only strong enough to stop dirt from starting to move u Works by exerting pressure and resistance into the trench walls creating arches of protection u Shoring system components F Simple shoring system F Shoring system with wales F Sheeting systems u Types of shoring systems F Timber F Screwjack F Pneumatic F Hydraulic

Course Content n Introduction n Trench Rescue Hazards n OSHA Regulations n Protective Systems n Shoring System Design n Rescue Shoring n Trench Rescue Operations