WELCOME

CORPORATE SAFETY TRAINING

29 CFR 1926.650-653

TRENCHING AND SHORING SAFETY

Introduce The Trenching & Shoring Safety Program

Establish The Programs Role.

Discuss the components of an effective program.

Introduce ideas to help develop an effective program.

Introduce Basic Skills in the Recognition & Control of Trenching & Shoring Hazards.

COURSE OBJECTIVES

APPLICABLE REGULATIONS

29 CFR 1926.650 - General Protection Requirements 29 CFR 1926.651 - Specific Excavation Requirements 29 CFR 1926.652 - Specific Trenching Requirements 29 CFR 1926.653 - Definitions Appendix - A - Excavations Appendix - B - Sloping and Benching Appendix - C - Timber Shoring for Trenches Appendix - D - Aluminum Hydraulic Shoring

BASIS FOR THE REGULATIONS

Hundreds of workers killed annually from cave-ins Thousand of workers injured annually from cave-ins Fatality rate for trenching is twice the level for general construction

PURPOSE OF THE PROGRAM

Peace of mind Reduced liability Increased productivity Reduced lost man-hours Improved employee morale Reduced or eliminated fines Improved health of employees Reduced injury and illness rates Lower workers’ compensation costs Because it’s the right thing to do!!!!!!

REASONS TO MAINTAIN AN EFFECTIVE PROGRAM:

MECHANISM OF DEATH

Asphyxiation

Each time a breath is exhaled the weight of the load restricts inhalation of the next breath. Slow suffocation usually follows unless rescue is immediate.

DYNAMIC SITE CONDITIONS

CAVE-INS RESULT FROM:

Vibrations Adjacent Structures Freezing and Thawing The Weight of the Soil Itself Addition or Removal of Water Reduction in Frictional and Cohesive Capacities of Soil

HOW MUCH DOES SOIL WEIGH?

DEPENDING ON THE DENSITY AND WATER CONTENT:

One cubic yard weighs - 3000lbs or more One cubic foot weighs - 100lbs or more

3000lbs or more

3 FEET

100lbs or more

1 FOOT

HOW DO MOST DEATHS OCCUR?

Instantaneously

Trenches 5 to 15 deep

With absolutely no warning

In seemingly safe conditions

With workers in a bent or lying position

SITE EVALUATION

BEFORE YOU BEGIN EXCAVATION:

The site must be assessed Potential hazards must be determined Known hazards reduced or eliminated Emergency procedures established Periodic inspection intervals determined Utility locations must be staked or marked

BASIC SAFETY REQUIREMENTS

Conduct inspections before each work shift Do not travel under elevated loads Do not work over unprotected employees Wear proper personal protective equipment Provide walkways or bridges over trenches Provide trench exits within 25 feet of workers in trenches more than four feet deep Ensure spoilage is at least 2 ft. from trench edges

EMERGENCY PROCEDURES

Immediately call 911, or the Emergency Response Team Report: - Exact Location - Number of Victims - Nature of Emergency - Trench Measurements - Special Hazards Keep all life-support and dewatering systems operating Clear workers away from the excavation Shut down heavy equipment Be prepared to meet and brief rescue personnel

EMERGENCY PROCEDURES

What not to do: - Don’t Panic!

- Control would-be rescuers

- Don’t sacrifice anyone else - Never attempt to dig someone out using motorized equipment Remember - Your actions could save a life!

Continued

FOOT AND VEHICLE TRAFFIC

ACCIDENT PREVENTION METHODS:

Warn and reroute public traffic Post signs, barricades and flagmen Mandate use of reflective vests Warn site traffic with stoplogs etc. Install protective supports systems

SURFACE ENCUMBRANCES

MUST BE: Removed Relocated Supported to protect site personnel

EXAMPLES INCLUDE:

Fencing Posts Telephone Cable Electrical Access Boxes

UNDERGROUND INSTALLATIONS

Utility lines must be located before excavating begins

Utility companies or owners must be contacted:

-- Response times must be considered

-- Advised of the proposed work

-- Questioned concerning underground installations need to be answered

UNDERGROUND INSTALLATIONS

If no response is given within 24 hours* work can cautiously proceed *(local timeframes may vary) Underground installations must be determined by safe and acceptable means

Excavated underground installations must be protected

Never under estimate hazards associated with underground utilities!!!

Continued

STRUCTURAL RAMPS: USED ONLY BY PEOPLE DESIGNED BY A “COMPETENT PERSON”

EGRESS REQUIRED EVERY 25 FEET (LATERAL) > = 4FT

ACCESS AND EGRESS

TRENCHES MORE THAN 5 FEET:

Require shoring Or must have a stabilized slope

IN HAZARDOUS SOIL CONDITIONS:

Trenches under 5 feet need protection

TRENCH SAFETY

TESTING AND CONTROLS:

Oxygen deficiency Flammable atmospheres Testing

EMERGENCY RESCUE EQUIPMENT:

Availability Lifelines

HAZARDOUS ATMOSPHERES

SAFELINE

SAFELINE

BACK-UPFALL PROTECTION

WINCH

TRIPOD

TIE-OFF POINT

HAZARDS & WATER ACCUMULATION

Adequate Precautions Must Be Taken When Working in Accumulated Water

Controlling Water and Water Removal Must Be Monitored by a Competent Person

Ditches, Dikes or Comparable Means Should Be Used to Prevent Surface Water From Entering Excavations

WEATHER FACTORS

Don’t under estimate the effects weather can have Weather can have a drastic effect on the site Daily (or hourly) site inspections must be made Consider protection from:

Lightning Flooding Erosion High winds Hot or Cold Temperatures

STABILITY OF ADJACENT STRUCTURES

When stability is endangered support systems must be used.

Excavation below the base of a foundation will not be permitted when it poses a hazard except when:

– A support system is provided– The excavation is in stable rock– A registered professional has approved the site or deemed

the situation will not pose a hazard

SITE INSPECTIONS

Daily inspections must be made by a competent person of:

When evidence is found of a hazardous condition, the exposed employees must be Immediately removed from the area.

Excavations Adjacent areas Protective systems

FALL PROTECTION

Guardrails must be provided for crossing over excavations

Barriers must be provided for remotely located excavations

SOIL CLASSIFICATION SYSTEM

TYPE A SOILS - Clay - Silty Clay - Sandy Clay - Clay Loam

TYPE B SOILS - Granular Cohesionless Soils (Silt Loam)

TYPE C SOILS - Gravel - Sand - Loamy Sand

SOIL CLASSIFICATION SYSTEM

SOIL CLASSIFICATION MUST BE DONE BY A COMPETENT PERSON:

Continued

Check entire worksite Fissured ground Layered soil Disturbed earth Seepage Vibration Poor drainage

VISUAL TEST

A B C

SOIL CLASSIFICATION SYSTEMContinued

Plasticity Dry Strength Thumb penetration Pocket penetrameter Hand operated shear vane

MANUAL TEST

A B C

WARNING: One soil inspection and classification may not be enough. Outside disturbances during excavation may change even the best soil classification. Inspect the soil after any change in conditions.

TYPE A SOILS

Are cohesive soils with an unconfined, compressive strength of 1.5 t/sf.

Clues that soil is not type A:– If it is fissured– If it is subject to vibration– If it has been previously disturbed– If the soil is part of a sloped, layered system– If the material is subject to other factors that would require

it to be classified as a less than stable material

A B C

TYPE B SOILS

Are cohesive soils with an unconfined compressive strength greater than 0.5 t/sf

Types include angular gravel, silt, silt loam, sandy loam and silty clay loam

Previously disturbed soils except those which would be classified as type C

Dry rock that is not stable

A B C

TYPE C SOILS

Are cohesive soil with an unconfined compressive strength of .5 t/sf

Are granular soils including gravel, sand, and loamy sand

Submerged soil or soil from which water is seeping

Submerged rock that is not stable

A B C

REQUIREMENTS FOR PROTECTIVE SYSTEMS

Each employee must be protected from cave-ins by an adequately designed system. Exceptions are:

Excavations made in stable rockExcavations less than 5 feet

Protective systems must have the capacity to resist all loads that are expected to be applied to the system

DESIGN OF BENCHING AND SLOPING SYSTEMS:

– OPTION 1 - Allowable configurations and slopes

– OPTION 2 - Determination of slopes and configurations using 29 CFR 1926.652

– OPTION 3 - Designs using other tabulated data

– OPTION 4 - Design by a registered professional engineer

Continued

REQUIREMENTS FOR PROTECTIVE SYSTEMS

MATERIALS AND EQUIPMENT

Must be free from damage or defects that might impair proper function

Must be used and maintained in a manner that is consistent with the recommendations of the manufacturer

Must be examined by a competent person if damage occurs

INSTALLATION AND REMOVAL OF SUPPORT

GENERAL REQUIREMENTS Support systems must be securely connected

Support systems must be installed and removed in a manner that protects from collapse

Support systems must not be subjected to loads exceeding design specifications

INSTALLATION AND REMOVAL OF SUPPORT

GENERAL REQUIREMENTS

Additional precautions must be taken to ensure safety before temporary removal begins

Removal must begin at the bottom of the excavation

Backfilling must progress together with the removal of support systems from excavations

Continued

SLOPING AND BENCHING SYSTEMS

EMPLOYEES MUST NOT BE PERMITTED TO WORK:

On the faces of sloped or benched excavations

At levels above other employees except when employees at the lower levels are adequately protected from the hazard of falling, rolling or sliding material or equipment

SLOPING AND BENCHING SYSTEMS

TEMPORARY SPOIL PILES:

2 FEET MINIMUM

Continued

SLOPING AND BENCHING SYSTEMSContinued

SLOPING GENERAL REQUIREMENTS

Various slope angles are allowed by OSHA

Appendix B to 1926 Subpart P must be consulted

Evacuate the excavation if walls show signs of distress

If soil conditions change, re-inspect.

SLOPING AND BENCHING SYSTEMSContinued

BENCHING GENERAL REQUIREMENTS

Various slope angles are allowed by OSHA

Appendix B to 1926 Subpart P must be consulted

Evacuate the excavation if walls show signs of distress

If soil conditions change, re-inspect.

TYPE B

34 DegreesMaximum

53 DegreesMaximum

45 DegreesMaximum

90 Degrees

TYPE A

TYPE C

STABLE ROCK

SLOPING AND BENCHING SYSTEMSContinued

20FEETMAX

3/4

1

TYPE A SOILS

BENCHING EXAMPLE

SLOPING EXAMPLE

20FEETMAX

1

1

TYPE B SOILS

SHORING SYSTEMS

WALES

SHEETING

JACKS/CROSSBRACES

GENERAL

Shoring provides a framework to work in Shoring uses wales crossbraces and uprights Shoring supports excavation walls

OSHA TABLES PROVIDE SHORING DATA

Soil type must be known Depth and width of the excavation must be known You must be familiar with the OSHA Tables

ContinuedSHORING SYSTEMS

REMOVAL

Remove shoring from the bottom up Pull sheeting out from above Backfill immediately after removal of support system

ContinuedSHORING SYSTEMS

WALES

SHEETING

JACKS/CROSSBRACES

PNEUMATIC/HYDRAULICJACKS

SCREWJACK

ContinuedSHORING SYSTEMS

SHIELD SYSTEMS

GENERAL

Shield systems must project at least 18 inches above the lowest point where the excavation face begins to slope

At Least 18 Inches

SHIELD SYSTEMS

GENERAL

Shield systems must not be subjected to loads exceeding those which the system was designed to withstand

Shields must be installed to restrict hazardous movement

Employees must be protected from the hazard of cave-ins when entering or exiting the areas protected by shields

Employees must not be allowed in shields when shields are being installed, removed, or moved vertically

Continued

SHIELD SYSTEMS

COMMON TRENCH SHIELD

Continued

SHIELD SYSTEMS

Systems may be connected

Systems may be stacked

Configuration must by consistent with the recommendations of the manufacturer

Must be examined by a competent person if damage occurs

Continued

REMEMBER, YOU CONTROL YOUR SITE!

REVIEW THEIR PROCEDURES WITH THEM BEFORE STARTING THE JOB!

DETERMINE THEIR SAFETY PERFORMANCE RECORD!

DETERMINE WHO IS IN CHARGE OF THEIR PEOPLE!

DETERMINE HOW THEY WILL AFFECT YOUR EMPLOYEES!

TIPS FOR USING CONTRACTORS