Questions and Answers
Match the following definitions to their related statements:
A technique that employs a specific angle of incline on the sides of the excavation = Sloping A structure that supports the sides of an excavation and protects against cave-ins = Shoring
A(n) _______ is capable of identifying existing and predictable hazards in surroundings or working conditions that are unsanitary, hazardous, or dangerous to employees.
competent person
A narrow underground excavation that is deeper than it is wide and no wider than 15 feet (4.5 meters) is called a ______.
trench
All of the following are OSHA's most cited violations in excavations, except:
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Structural ramps and runways must be designed by a qualified person.
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When creating a hazard to employees, these must be removed or supported as necessary to safeguard employees working in the area:
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Before excavation work can begin, it is necessary to determine the location of the utilities underground.
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Structural ramps and runways must be designed by a competent person.
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Match the responsibilities to the related persons:
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Inspections must be made by a competent person after rainstorms and any other hazard-increasing occurrence.
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Walkways over excavations must conform to OSHA standards with guardrails over 12 feet.
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Spoils and equipment must be set at least _____ feet back from the excavation.
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Which of the following are OSHA standards for excavations?
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Match the correct weight to the appropriate type of soil:
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Match the following definitions to the appropriate soil types:
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Type C soil cannot be benched.
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A 10-foot column of dirt could weigh up to 1,200 pounds.
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Soil cannot be Type A if it is:
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Which of the following is required for protective system equipment?
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Hydraulic shoring must be checked weekly for defective parts.
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If it is determined to be unsuitable, all equipment must be removed from service until _______ approves it for use.
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OSHA requires that all excavations in which employees could potentially be exposed to cave-ins be protected by:
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Match the following soil types to their maximum allowable slopes:
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Sloping or benching for excavations greater than 20 feet deep must be designed by a registered professional engineer.
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The steepest incline of an excavation face that is acceptable for the most favorable site conditions is called the ______.
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Benching is allowed in Type C soil.
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Match the basic types of shoring to their related statements:
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Shields may be used in combination with benching and shoring.
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Any modifications to shields must be approved by the ______.
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Hydraulic shoring must be checked at least ______ for leaking hoses and/or cylinders.
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Where oxygen deficiency exists, the atmospheres in the excavation must be tested before employees enter excavations greater than ______ in depth.
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Cave-ins pose the greatest risk and are much more likely than other excavation-related accidents to result in worker fatalities.
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Most accidents occur in trenches _____ feet deep.
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A condition that contributes to a serious hazard during excavation operations includes:
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Fire is not considered a hazard associated with excavations.
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A competent person is capable of identifying existing and predictable hazards in surrounding or working conditions.
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______ are the deadliest excavation hazards.
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It is permissible to enter an excavation to get a soil sample.
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Type C soil is the least stable soil.
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What type of soil cannot be benched?
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The primary types of protective systems are sloping, benching, shoring, and shielding.
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All excavations over ______ feet in depth must be designed by a registered professional engineer.
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Protective systems are selected and constructed by the employer, who is free to choose any design, regardless of required performance criteria.
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Study Notes
Excavation Techniques and Safety
- Sloping: Involves a specific angle of incline on excavation sides to prevent cave-ins.
- Shoring: A structural support for excavation walls, protecting against collapses.
Competent Person Definition
- A competent person can identify hazards related to work conditions and has the authority to take corrective action.
Types of Excavations
- Trench: A narrow underground excavation deeper than its width, specifically no wider than 15 feet (4.5 meters).
OSHA Violations
- Annual inspections by a competent person are not included among the most cited violations in excavations.
Soil Weight
- Moist soil weighs approximately 120 lbs per cubic foot; dry soil weighs about 85 lbs per cubic foot.
Soil Types Classification
- Type A: Most stable soil type.
- Type B: Granular, cohesion-less soil including materials like angular gravel and sandy loam.
- Type C: Cohesive soil with unconfined compressive strength of 0.5 tsf (48 kPa) or less.
- Stable Rock: Allows for vertical excavations.
Excavation Safety Procedures
- Surface encumbrances must be removed or supported to safeguard employees.
- Underground utility locations must be confirmed before excavation starts.
- Employees around excavations exposed to vehicular traffic must wear high visibility apparel.
- Inspections by a competent person are required after rainstorms to assess hazards.
Maximum Allowable Slopes
- Stable Rock: Maximum slope of 90 degrees (vertical).
- Type A Soil: Slope ratio of 3/4:1 (53 degrees).
- Type B Soil: Slope ratio of 1:1 (45 degrees).
- Type C Soil: Slope ratio of 1 1/2:1 (34 degrees).
Shoring Types
- Timber Shoring: Expensive and challenging method of shoring.
- Aluminum Hydraulic Shoring: Offers safety without trench entry for installation.
Excavation Depth Regulations
- Hydraulic shoring requires checks for defects at least once per shift.
- Excavations deeper than 20 feet need design by a registered professional engineer.
Safety and Hazards
- Cave-ins pose the highest risk and lead to the majority of excavation-related fatalities.
- Injuries typically occur in trenches between 5 to 15 feet deep.
- Types of hazards include collapsing soil, machinery, and unsafe weather conditions.
Additional Facts
- Type C soil cannot be benched and is considered the least stable.
- A competent person monitors site conditions to prevent hazardous situations.
- Fire hazards are generally not associated with excavations.
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Description
Test your knowledge on excavation practices with this quiz. It covers important terms, definitions, and safety measures related to excavation. Perfect for students and professionals in the construction and engineering fields.
