OSHA 10-Hour Construction ReviewExcavationsEasy
A trench is being excavated in soil classified as Type A. The excavation is 6 feet deep. According to OSHA standards, what is the maximum allowable slope for the sides of the trench?
- A0.75H:1V (53 degrees)
- B1.5H:1V (34 degrees)
- C1H:1V (45 degrees)
- D2H:1V (26.5 degrees)
Show answer & explanationAnswer & explanation
Correct answer: A. 0.75H:1V (53 degrees)
OSHA regulations specify that for Type A soil, the maximum allowable slope for excavations 20 feet or less in depth is 0.75H:1V (53 degrees from the horizontal). This slope is considered stable for this soil type.
Why the other options are wrong
- B. This slope is typically for Type B soil, which is less stable than Type A.
- C. This slope is generally for Type C soil in some specific circumstances or for certain granular soils, but not the standard for Type A.
- D. This slope is typically for Type C soil, which requires the least steep slope due to its instability.
Type A Soil Sloping
Type A soil is the most stable soil type according to OSHA's classification system, allowing for the steepest excavation slopes.
- Maximum slope for Type A soil is 0.75H:1V (53 degrees).
- Applies to excavations 20 feet or less in depth.
- Requires competent person evaluation.
Memory trick: Always Be Careful: A is steepest, C is shallowest for safety.