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Excavating and Trenching

1926 Subpart P

Tommy Adams

on 1 April 2016

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Transcript of Excavating and Trenching

Subpart P
Excavating and Trenching
About two workers are killed every month in trenching or excavating accidents
Hazards of Excavation
OSHA information on Excavation
Planning for Safety
Trench Box and Shield
Excavating and Trenching are defined as two separate items within OSHA regulation
- any man-made cut, cavity, trench or depression in an earth surface made by earth removal
- narrow underground excavation that is deeper than it is wide, and it is no wider than 15 feet
Falling Objects
Moving Equipment
Hazardous Atmospheres
Underground Utilities
Lack of cave in protection was the #2 cited violation this past year
Research done by OSHA in the 1980's during the revision of the standards showed that the fatality rate in excavation work was 112% greater than that of construction in general
Standards and Regulations-1926-Subpart P-Excavations
1926-Subpart P- Excavations
Purpose: Sets guidelines/rules that contractors and subs must follow
1926.650 - Scope, application, and definitions applicable to this subpart.
1926.651 - Specific Excavation Requirements.
1926.652 - Requirements for protective systems.
1926 Subpart P App A - Soil Classification
1926 Subpart P App B - Sloping and Benching
1926 Subpart P App C - Timber Shoring for Trenches
1926 Subpart P App D - Aluminum Hydraulic Shoring for Trenches
1926 Subpart P App E - Alternatives to Timber Shoring
1926 Subpart P App F - Selection of Protective Systems
Nearby Traffic
Proximity and physical condition of nearby structures
Surface and ground water
Location of the water table
Location of overhead and underground utilities
Safety and Health Program
Systematic Identification
Prevention/Control of hazards
Can be written or verbal but must be unique to the project
Train every employee
Incorporate fast notification and investigation of accidents
On-the-job Evaluation
Competent Person
After natural events (rain)
After man made events(blasting)
What is Inspected?
All excavations
Adjacent areas for possible cave-ins
Protective systems and equipment
Proper use of safety equipment
Hazardous Atmospheres/ Conditions
Soils impact on Excavation
Support Systems
Sloping/ Benching
Hydraulic Systems
Steel/Plywood Plates
Prevent Collapse
Deep Excavation
Driven Prefabricated Sections
Trench box
Protect Workers
Sloping Shielding or Shoring
Sloping-General Rules
No steeper than 1 to 1 1/2 slope (34 Degrees)
Type C soil
20 ft depth or less
Any gradation less than this is acceptable for any type of soil
Sloping Guidelines
No Sloped Trench may be more than 20' deep
Trench Box/ Shield
OSHA regulation does not require any protective system when an excavation is made
entirely of solid rock
or is
less than 5 ft. deep
and has been examined by a competent person
Trench Boxes
Trench Boxes
Designed to allow workers to do their jobs within the plates of the box
Trench boxes
Engineered steel or aluminum structures that are used to protect workers inside trenches
Stand-up time- amount of time a trench will last from the time its dug till the time its walls start to cave in (a few seconds to several months)
Safety Precautions
OSHA standard prohibits excavation under level of a base, footing, foundation, or retaining walls
Entirely stable rock
Support System(underpinning) provided
RPE determines structure is significantly removed from the excavation
Installation and removal of protective systems
Securely connect members
Safely install
Never overload members
Install temporary structural members when necessary
Excavation below bottom members of the support system = 2 feet or less
Support system to be removed from bottom up
Falls and Equipment
Materials/Equipment at least 2 ft
Provide warning systems
Stop logs
Alert operations
Prohibit employees from working above others (sloped/benched)
Prohibit employees working under loads handled by digging/ lifting equipment
Hazardous Atmosphere Provision
Test any excavation where oxygen deficiency or hazardous atmosphere exists
Respiratory Protection or ventilation
Employer must provide emergency rescue equipment
Breathing apparatus
Safety harness/line
Basket stretcher
Hazardous Atmospheres Examples
Oxygen Deficient Atmospheres
Rainwater+limestone=acidity reaction=carbon dioxide
Flammable/Combustive/Explosive Atmospheres
VOC's from petroleum products (buried tanks etc.)
Methane-naturally from breakdown of certain materials( sewage, leaves, weeds)
Toxic Atmospheres
Carbon monoxide from vehicles or equipment
Access and Egress
Excavations deeper than 4 ft
Safe means of egress within 25 ft of lateral travel
-Ladders, steps, ramps, runways, etc
Ramps/ Runways
-designed by a competent person
-Uniform thickness/properly joined
Top Cited Standards
Specific excavation requirements
Requirements for protective systems
Head Protection
Hazard Communication
Safety Training and education
Test any Excavation >4 ft
Full transcript