excavation for construction. industries engaged in excavation v general contractors v highway and...

Excavation for Excavation for ConstructionConstruction

Industries engaged in Industries engaged in excavationexcavation

General contractorsGeneral contractors

Highway and Highway and street construction street construction contractorscontractors

Bridge and tunnel Bridge and tunnel contractorscontractors

1a

Industries engaged in Industries engaged in excavationexcavation

Water, sewer, pipeline contractorsWater, sewer, pipeline contractors

Communication and Communication and power line power line contractorscontractors

Concrete worker Concrete worker and well drilling and well drilling contractorscontractors

1b

Hazards of excavation Hazards of excavation workwork

Cave-insCave-ins

Underground Underground utilitiesutilities

Materials/Materials/equipment falling into excavation equipment falling into excavation sitessites

2a


Struck-by accidentsStruck-by accidents

AsphyxiationAsphyxiation

ExplosionsExplosions

FallsFalls

2b


ElectrocutionsElectrocutions

DrowningDrowning

2c

Safety considerationsSafety considerations

Excavation is one of the most Excavation is one of the most hazardous types of work in the hazardous types of work in the construction industryconstruction industry

Accidents result Accidents result from inadequate from inadequate planningplanning

Build safety into Build safety into pre-bid planningpre-bid planning

3a


Plan safety into the job. Consider:Plan safety into the job. Consider:• TrafficTraffic• Nearness of structures Nearness of structures

and their and their conditionsconditions

• SoilSoil

3b


Plan safety into the job. Consider:Plan safety into the job. Consider:• Surface and ground waterSurface and ground water• Water tableWater table• Overhead/Overhead/

underground underground utilitiesutilities

• WeatherWeather

3c

Jobsite safety and health Jobsite safety and health programsprograms

Establish and maintain a safety and Establish and maintain a safety and health program for the worksitehealth program for the worksite

Provide adequate systematic Provide adequate systematic policies, procedures, practicespolicies, procedures, practices

Recognize job-related safety/health Recognize job-related safety/health hazardshazards

4a


Safety and health programs should Safety and health programs should reflect the unique characteristics of reflect the unique characteristics of the jobsitethe jobsite

Proper implementation depends on Proper implementation depends on cooperation among:cooperation among:• supervisorssupervisors• employee groupsemployee groups• individual employeesindividual employees

4b


Supervisors must understand Supervisors must understand his/her degree of his/her degree of responsibility/authorityresponsibility/authority

Get unions involvedGet unions involved

4c

Locating utilitiesLocating utilities

Employers must determine the Employers must determine the estimated locations of utility estimated locations of utility installationsinstallations

Contact utility Contact utility companies before companies before starting excavationstarting excavation

Utility owners must attempt to find Utility owners must attempt to find exact location of utilitiesexact location of utilities

5a

Locating utilitiesLocating utilities

Proceed with caution if the exact Proceed with caution if the exact location of utilities cannot be foundlocation of utilities cannot be found

Use safe and Use safe and acceptable means to acceptable means to locate exact locations of locate exact locations of installationsinstallations

5b

Safety starts at the Safety starts at the surfacesurface

Surface encumbrances that create Surface encumbrances that create hazards must be hazards must be removed/supportedremoved/supported

Wear warning vests when near Wear warning vests when near traffictraffic

Employees must be trained to Employees must be trained to operate heavy equipmentoperate heavy equipment

6a


Stay away from loads being Stay away from loads being handled by lifting/digging handled by lifting/digging equipmentequipment

Stay away from vehicles being Stay away from vehicles being loaded/unloadedloaded/unloaded

6b


Use barricades, hand or Use barricades, hand or mechanical signals, stop logs to mechanical signals, stop logs to keep operators safekeep operators safe

6c


Warn mobile equipment operators Warn mobile equipment operators about the edge of the excavation about the edge of the excavation sitesite

Keep the grade away from the Keep the grade away from the excavation siteexcavation site

6d


Take care when walking near Take care when walking near excavation sitesexcavation sites

Barricade or cover Barricade or cover wells, pits, shaftswells, pits, shafts

Use appropriate Use appropriate PPEPPE

6e

Protecting utilitiesProtecting utilities

Exact locations of utilities must be Exact locations of utilities must be determineddetermined

Utilities must Utilities must be exposed be exposed before diggingbefore digging

7a

Protecting utilitiesProtecting utilities

Excavation sites must be Excavation sites must be protected, supported to safeguard protected, supported to safeguard employeesemployees

Approach Approach utility lines as utility lines as if they are if they are land minesland mines

7b

Employee access/egress Employee access/egress from excavationsfrom excavations

Ramps must be designed by a Ramps must be designed by a competent personcompetent person

Ramps must be structurally sound Ramps must be structurally sound and not create a tripping hazardand not create a tripping hazard

Use surface treatments on ramps Use surface treatments on ramps to prevent slippingto prevent slipping

8a


Trenches 4 or more feet deep need Trenches 4 or more feet deep need a safe means of egressa safe means of egress• StairwayStairway• LadderLadder• RampsRamps

Means of egress must be fixed and Means of egress must be fixed and securesecure

8b


Means of egress must be within 25 Means of egress must be within 25 feet of workersfeet of workers

Ladders must extend a minimum Ladders must extend a minimum of 36 inches above the landingof 36 inches above the landing

Use metal ladders with caution Use metal ladders with caution around utilitiesaround utilities

8c

Hazardous atmospheresHazardous atmospheres

ExplosiveExplosive

FlammableFlammable

PoisonousPoisonous

CorrosiveCorrosive

9a


OxidizingOxidizing

IrritatingIrritating

Oxygen Oxygen deficientdeficient

ToxicToxic

9b


Operations inside an excavation Operations inside an excavation can introduce a hazardous can introduce a hazardous atmosphereatmosphere

Test the air of excavation sites Test the air of excavation sites more than 4 feet deep before more than 4 feet deep before enteringentering

9c


Take extra precautions when the Take extra precautions when the atmosphere has:atmosphere has:• less than 19.5 percent, or more than less than 19.5 percent, or more than

23.5 percent oxygen23.5 percent oxygen• a combustible gas concentration a combustible gas concentration

greater than 20 percent of the lower greater than 20 percent of the lower flammable limitflammable limit

• concentrations of hazardous substances concentrations of hazardous substances that exceed threshold limit valuesthat exceed threshold limit values

9d


Conduct all operations within OSHA Conduct all operations within OSHA requirementsrequirements

Regularly conduct atmospheric Regularly conduct atmospheric testing if atmospheric hazards are testing if atmospheric hazards are presentpresent

9e


Wear respiratory equipment when Wear respiratory equipment when requiredrequired

Know the hazards of confined Know the hazards of confined spacesspaces

9f

Emergency equipmentEmergency equipment

Emergency rescue equipment is Emergency rescue equipment is required when there is a risk for required when there is a risk for hazardous atmosphereshazardous atmospheres

Emergency rescue equipment Emergency rescue equipment must be attended when in usemust be attended when in use

10a

Emergency equipmentEmergency equipment

Respirators must be suitable for Respirators must be suitable for the type of exposurethe type of exposure

Independent lifelines must be Independent lifelines must be provided when appropriateprovided when appropriate

10b

Water accumulation Water accumulation hazardshazards

Employees are prohibited from Employees are prohibited from entering excavation sites with entering excavation sites with accumulated water unless accumulated water unless adequate protection has been adequate protection has been providedprovided

11a


Methods for controlling standing Methods for controlling standing water include:water include:• special support/shield systemsspecial support/shield systems• water removal equipmentwater removal equipment• safety harnesses and lifelinessafety harnesses and lifelines

11b


Workers should be prepared to Workers should be prepared to leave excavation sites if control leave excavation sites if control measures begin to failmeasures begin to fail

Use diversion ditches or dikes to Use diversion ditches or dikes to prevent surface water from prevent surface water from entering excavation sitesentering excavation sites

11c


Competent person inspects Competent person inspects excavation sites subject to water excavation sites subject to water runoffrunoff

11d

Protect structures next to Protect structures next to excavation sitesexcavation sites

Use support systems to keep Use support systems to keep nearby buildings, walls stablenearby buildings, walls stable• ShoringShoring• BracingBracing• UnderpinningUnderpinning

12a


Excavation below the base of a Excavation below the base of a footing or retaining wall is prohibited footing or retaining wall is prohibited unless a support system is providedunless a support system is provided

Excavations under Excavations under sidewalks/pavements are prohibited sidewalks/pavements are prohibited unless a support system is usedunless a support system is used

12b


Workers must be prepared to leave Workers must be prepared to leave excavation sites if support systems excavation sites if support systems begin to failbegin to fail

12c

Loose rock and soil as Loose rock and soil as hazardshazards

Prevent loose rock/soil from falling Prevent loose rock/soil from falling onto employees in excavation sitesonto employees in excavation sites

Use barricades to Use barricades to contain materialcontain material

13a

Loose rock and soil as Loose rock and soil as hazardshazards

Keep surface materials at least 2 Keep surface materials at least 2 feet from the edge of excavation feet from the edge of excavation sitessites

Keep employees Keep employees off of sloped off of sloped surfaces at levels surfaces at levels above other above other employeesemployees

13b

Protective systemsProtective systems

Excavations where employees are Excavations where employees are exposed to cave-ins must be exposed to cave-ins must be protected by:protected by:• sloping or benchingsloping or benching• support systemssupport systems• shield systemsshield systems• other protective other protective

systemssystems

14a


Protective systems are not needed Protective systems are not needed if the excavation is:if the excavation is:• made in stable rockmade in stable rock• less than 5 feet deepless than 5 feet deep

Employers are free to choose the Employers are free to choose the most practical design most practical design approach for a particular approach for a particular circumstancecircumstance

14b


Designing a protective system is Designing a protective system is complexcomplex

Protective systems must be able to Protective systems must be able to resist all loadsresist all loads

A competent person must examine A competent person must examine protective systems’ materialsprotective systems’ materials

14c

Soil typesSoil types

Classify the soil type:Classify the soil type:• Stable rockStable rock• Type AType A• Type BType B• Type CType C

15a

Sloping and benchingSloping and benching

Slope the excavation’s sides to a Slope the excavation’s sides to a safe anglesafe angle

Slope angle not be steeper than 1 Slope angle not be steeper than 1 1/2 horizontal to 1 or less vertical is 1/2 horizontal to 1 or less vertical is safesafe

Soil classification may not be Soil classification may not be needed if sloped to this angleneeded if sloped to this angle

16a


Other slopes may be used for other Other slopes may be used for other soil typessoil types

Benching systems excavate the Benching systems excavate the sides of an excavation to form a sides of an excavation to form a series of horizontal levels or stepsseries of horizontal levels or steps

16b


Benching systems have vertical or Benching systems have vertical or near-vertical surfaces between near-vertical surfaces between levelslevels

16c

Support, shield, and Support, shield, and protective systemsprotective systems

Shoring systems support the sides Shoring systems support the sides of the excavation with:of the excavation with:• timbertimber• aluminumaluminum• hydraulic, hydraulic,

pneumatic, or pneumatic, or mechanical mechanical systemssystems

17a

Support, shield, and Support, shield, and protective systemsprotective systems

Shoring systems are made up of Shoring systems are made up of cross braces, wales, and uprightscross braces, wales, and uprights

Selection and Selection and design involves design involves using tabulated using tabulated datadata

17b

Precautions when protective Precautions when protective systems are being installedsystems are being installed

Securely connect members of Securely connect members of support systemssupport systems

Safely install support systemsSafely install support systems

Never overload members of Never overload members of support systemssupport systems

18a

Install other structural members to Install other structural members to carry loads when temporary carry loads when temporary removal of members is necessaryremoval of members is necessary

The installation of support systems The installation of support systems must be closely coordinated with must be closely coordinated with the excavation processthe excavation process

18b

Precautions when protective Precautions when protective systems are being installedsystems are being installed

Daily inspectionsDaily inspections

Inspect excavations for possible:Inspect excavations for possible:• cave-inscave-ins• failure of protective systemsfailure of protective systems• hazardous atmosphereshazardous atmospheres• other hazardous conditionsother hazardous conditions

19a

Trench failureTrench failure

Recognize hazardous conditionsRecognize hazardous conditions

Sudden changes can mean Sudden changes can mean disasterdisaster

20a


Things that can cause immediate Things that can cause immediate change include:change include:• bulldozers coming too close to the bulldozers coming too close to the

trenchtrench• a sudden downpoura sudden downpour• striking an underground utility linestriking an underground utility line

20b


Tension cracks can cause sliding, Tension cracks can cause sliding, sluffing, or topplingsluffing, or toppling

Unsupported excavation can cause Unsupported excavation can cause bulging in the vertical facebulging in the vertical face

20c


Downward pressure can cause Downward pressure can cause bottom heaving or squeezingbottom heaving or squeezing

Upward water flow can cause Upward water flow can cause boiling in the bottom of the boiling in the bottom of the excavationexcavation

20d

excavation for construction. industries engaged in excavation v general contractors v highway and...

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excavation v water

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hazardous atmosphere

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