Excavation for Construction Industries engaged in excavation v

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Excavation for Construction

Excavation for Construction

Industries engaged in excavation v General contractors v Highway and street construction contractors v

Industries engaged in excavation v General contractors v Highway and street construction contractors v Bridge and tunnel contractors 1 a

Industries engaged in excavation v Water, sewer, pipeline contractors v Communication power line contractors

Industries engaged in excavation v Water, sewer, pipeline contractors v Communication power line contractors and v Concrete worker and well drilling contractors 1 b

Hazards of excavation work v Cave-ins v Underground utilities v Materials/ equipment falling into

Hazards of excavation work v Cave-ins v Underground utilities v Materials/ equipment falling into excavation sites 2 a

Hazards of excavation work v Struck-by accidents v Asphyxiation v Explosions v Falls 2

Hazards of excavation work v Struck-by accidents v Asphyxiation v Explosions v Falls 2 b

Hazards of excavation work v Electrocutions v Drowning 2 c

Hazards of excavation work v Electrocutions v Drowning 2 c

Safety considerations v Excavation is one of the most hazardous types of work in

Safety considerations v Excavation is one of the most hazardous types of work in the construction industry v Accidents result from inadequate planning v Build safety into pre-bid planning 3 a

Safety considerations v Plan safety into the job. Consider: • Traffic • Nearness of

Safety considerations v Plan safety into the job. Consider: • Traffic • Nearness of structures and their conditions • Soil 3 b

Safety considerations v Plan safety into the job. Consider: • Surface and ground water

Safety considerations v Plan safety into the job. Consider: • Surface and ground water • Water table • Overhead/ underground utilities • Weather 3 c

Jobsite safety and health programs v Establish and maintain a safety and health program

Jobsite safety and health programs v Establish and maintain a safety and health program for the worksite v Provide adequate systematic policies, procedures, practices v Recognize job-related safety/health hazards 4 a

Jobsite safety and health programs v Safety and health programs should reflect the unique

Jobsite safety and health programs v Safety and health programs should reflect the unique characteristics of the jobsite v Proper implementation depends on cooperation among: • supervisors • employee groups • individual employees 4 b

Jobsite safety and health programs v Supervisors must understand his/her degree of responsibility/authority v

Jobsite safety and health programs v Supervisors must understand his/her degree of responsibility/authority v Get unions involved 4 c

Locating utilities v Employers must determine the estimated locations of utility installations v Contact

Locating utilities v Employers must determine the estimated locations of utility installations v Contact utility companies before starting excavation v Utility owners must attempt to find exact location of utilities 5 a

Locating utilities v Proceed with caution if the exact location of utilities cannot be

Locating utilities v Proceed with caution if the exact location of utilities cannot be found v Use safe and acceptable means to locate exact locations of installations 5 b

Safety starts at the surface v Surface encumbrances that create hazards must be removed/supported

Safety starts at the surface v Surface encumbrances that create hazards must be removed/supported v Wear warning vests when near traffic v Employees must be trained to operate heavy equipment 6 a

Safety starts at the surface v Stay away from loads being handled by lifting/digging

Safety starts at the surface v Stay away from loads being handled by lifting/digging equipment v Stay away from vehicles being loaded/unloaded 6 b

Safety starts at the surface v Use barricades, hand or mechanical signals, stop logs

Safety starts at the surface v Use barricades, hand or mechanical signals, stop logs to keep operators safe 6 c

Safety starts at the surface v Warn mobile equipment operators about the edge of

Safety starts at the surface v Warn mobile equipment operators about the edge of the excavation site v Keep the grade away from the excavation site 6 d

Safety starts at the surface v Take care when walking near excavation sites v

Safety starts at the surface v Take care when walking near excavation sites v Barricade or cover wells, pits, shafts v Use PPE appropriate 6 e

Protecting utilities v Exact locations of utilities must be determined v Utilities must be

Protecting utilities v Exact locations of utilities must be determined v Utilities must be exposed before digging 7 a

Protecting utilities v Excavation sites must be protected, supported to safeguard employees v Approach

Protecting utilities v Excavation sites must be protected, supported to safeguard employees v Approach utility lines as if they are land mines 7 b

Employee access/egress from excavations v Ramps must be designed by a competent person v

Employee access/egress from excavations v Ramps must be designed by a competent person v Ramps must be structurally sound and not create a tripping hazard v Use surface treatments on ramps to prevent slipping 8 a

Employee access/egress from excavations v Trenches 4 or more feet deep need a safe

Employee access/egress from excavations v Trenches 4 or more feet deep need a safe means of egress • Stairway • Ladder • Ramps v Means of egress must be fixed and secure 8 b

Employee access/egress from excavations v Means of egress must be within 25 feet of

Employee access/egress from excavations v Means of egress must be within 25 feet of workers v Ladders must extend a minimum of 36 inches above the landing v Use metal ladders with caution around utilities 8 c

Hazardous atmospheres v Explosive v Flammable v Poisonous v Corrosive 9 a

Hazardous atmospheres v Explosive v Flammable v Poisonous v Corrosive 9 a

Hazardous atmospheres v Oxidizing v Irritating v Oxygen deficient v Toxic 9 b

Hazardous atmospheres v Oxidizing v Irritating v Oxygen deficient v Toxic 9 b

Hazardous atmospheres v Operations inside an excavation can introduce a hazardous atmosphere v Test

Hazardous atmospheres v Operations inside an excavation can introduce a hazardous atmosphere v Test the air of excavation sites more than 4 feet deep before entering 9 c

Hazardous atmospheres v Take extra precautions when the atmosphere has: • less than 19.

Hazardous atmospheres v Take extra precautions when the atmosphere has: • less than 19. 5 percent, or more than 23. 5 percent oxygen • a combustible gas concentration greater than 20 percent of the lower flammable limit • concentrations of hazardous substances that exceed threshold limit values 9 d

Hazardous atmospheres v Conduct all operations within OSHA requirements v Regularly conduct atmospheric testing

Hazardous atmospheres v Conduct all operations within OSHA requirements v Regularly conduct atmospheric testing if atmospheric hazards are present 9 e

Hazardous atmospheres v Wear respiratory equipment when required v Know the hazards of confined

Hazardous atmospheres v Wear respiratory equipment when required v Know the hazards of confined spaces 9 f

Emergency equipment v Emergency rescue equipment is required when there is a risk for

Emergency equipment v Emergency rescue equipment is required when there is a risk for hazardous atmospheres v Emergency rescue equipment must be attended when in use 10 a

Emergency equipment v Respirators must be suitable for the type of exposure v Independent

Emergency equipment v Respirators must be suitable for the type of exposure v Independent lifelines must be provided when appropriate 10 b

Water accumulation hazards v Employees are prohibited from entering excavation sites with accumulated water

Water accumulation hazards v Employees are prohibited from entering excavation sites with accumulated water unless adequate protection has been provided 11 a

Water accumulation hazards v Methods for controlling standing water include: • special support/shield systems

Water accumulation hazards v Methods for controlling standing water include: • special support/shield systems • water removal equipment • safety harnesses and lifelines 11 b

Water accumulation hazards v Workers should be prepared to leave excavation sites if control

Water accumulation hazards v Workers should be prepared to leave excavation sites if control measures begin to fail v Use diversion ditches or dikes to prevent surface water from entering excavation sites 11 c

Water accumulation hazards v Competent person inspects excavation sites subject to water runoff 11

Water accumulation hazards v Competent person inspects excavation sites subject to water runoff 11 d

Protect structures next to excavation sites v Use support systems to keep nearby buildings,

Protect structures next to excavation sites v Use support systems to keep nearby buildings, walls stable • Shoring • Bracing • Underpinning 12 a

Protect structures next to excavation sites v Excavation below the base of a footing

Protect structures next to excavation sites v Excavation below the base of a footing or retaining wall is prohibited unless a support system is provided v Excavations under sidewalks/pavements are prohibited unless a support system is used 12 b

Protect structures next to excavation sites v Workers must be prepared to leave excavation

Protect structures next to excavation sites v Workers must be prepared to leave excavation sites if support systems begin to fail 12 c

Loose rock and soil as hazards v Prevent loose rock/soil from falling onto employees

Loose rock and soil as hazards v Prevent loose rock/soil from falling onto employees in excavation sites v Use barricades to contain material 13 a

Loose rock and soil as hazards v Keep surface materials at least 2 feet

Loose rock and soil as hazards v Keep surface materials at least 2 feet from the edge of excavation sites v Keep employees off of sloped surfaces at levels above other employees 13 b

Protective systems v Excavations where employees are exposed to cave-ins must be protected by:

Protective systems v Excavations where employees are exposed to cave-ins must be protected by: • sloping or benching • support systems • shield systems • other protective systems 14 a

Protective systems v Protective systems are not needed if the excavation is: • made

Protective systems v Protective systems are not needed if the excavation is: • made in stable rock • less than 5 feet deep v Employers are free to choose the most practical design approach for a particular circumstance 14 b

Protective systems v Designing complex a protective system is v Protective systems must be

Protective systems v Designing complex a protective system is v Protective systems must be able to resist all loads v. A competent person must examine protective systems’ materials 14 c

Soil types v Classify the soil type: • Stable rock • Type A •

Soil types v Classify the soil type: • Stable rock • Type A • Type B • Type C 15 a

Sloping and benching v Slope the excavation’s sides to a safe angle v Slope

Sloping and benching v Slope the excavation’s sides to a safe angle v Slope angle not be steeper than 1 1/2 horizontal to 1 or less vertical is safe v Soil classification may not be needed if sloped to this angle 16 a

Sloping and benching v Other slopes may be used for other soil types v

Sloping and benching v Other slopes may be used for other soil types v Benching systems excavate the sides of an excavation to form a series of horizontal levels or steps 16 b

Sloping and benching v Benching systems have vertical or near-vertical surfaces between levels 16

Sloping and benching v Benching systems have vertical or near-vertical surfaces between levels 16 c

Support, shield, and protective systems v Shoring systems support the sides of the excavation

Support, shield, and protective systems v Shoring systems support the sides of the excavation with: • timber • aluminum • hydraulic, pneumatic, or mechanical systems 17 a

Support, shield, and protective systems v Shoring systems are made up of cross braces,

Support, shield, and protective systems v Shoring systems are made up of cross braces, wales, and uprights v Selection and design involves using tabulated data 17 b

Precautions when protective systems are being installed v Securely connect members of support systems

Precautions when protective systems are being installed v Securely connect members of support systems v Safely install support systems v Never overload members of support systems 18 a

Precautions when protective systems are being installed v Install other structural members to carry

Precautions when protective systems are being installed v Install other structural members to carry loads when temporary removal of members is necessary v The installation of support systems must be closely coordinated with the excavation process 18 b

Daily inspections v Inspect excavations for possible: • cave-ins • failure of protective systems

Daily inspections v Inspect excavations for possible: • cave-ins • failure of protective systems • hazardous atmospheres • other hazardous conditions 19 a

Trench failure v Recognize hazardous conditions v Sudden changes can mean disaster 20 a

Trench failure v Recognize hazardous conditions v Sudden changes can mean disaster 20 a

Trench failure v Things that can cause immediate change include: • bulldozers coming too

Trench failure v Things that can cause immediate change include: • bulldozers coming too close to the trench • a sudden downpour • striking an underground utility line 20 b

Trench failure v Tension cracks can cause sliding, sluffing, or toppling v Unsupported excavation

Trench failure v Tension cracks can cause sliding, sluffing, or toppling v Unsupported excavation cause bulging in the vertical face 20 c

Trench failure v Downward pressure can cause bottom heaving or squeezing v Upward water

Trench failure v Downward pressure can cause bottom heaving or squeezing v Upward water flow can cause boiling in the bottom of the excavation 20 d