STSC Excavation and Trenching Safety 4

Question 1

When must a competent person inspect an excavation?

Accepted Answer

Daily and after any hazard-increasing event such as rain

Answer

OSHA requires a competent person to inspect excavations daily and after any event that could increase hazards, such as rainfall or vibration.

Question 2

What is the maximum depth of an excavation before a ladder or other safe means of egress is required?

Accepted Answer

4 feet

Answer

OSHA mandates that a ladder, stairway, or ramp be provided in excavations deeper than 4 feet.

Question 3

Which soil type is classified as the most stable under OSHA's soil classification system?

Accepted Answer

Type A

Answer

Type A soil is the most stable, exhibiting high cohesiveness and requiring the least-aggressive protective system.

Question 4

A trench is 6 feet deep and 3 feet wide. Workers must not be in the trench unless:

Accepted Answer

Adequate cave-in protection is in place

Answer

OSHA requires that cave-in protection (sloping, shoring, or trench box) be installed before workers enter any trench 5 feet or deeper.

Question 5

What minimum distance must spoil piles be kept from the edge of an excavation?

Accepted Answer

2 feet

Answer

OSHA requires excavated material (spoil) to be kept at least 2 feet from the edge to prevent it from falling back into the excavation.

(STSC) Safety Trained Supervisor Construction Practice Test