Practice Test Geeks(STSC) Safety Trained Supervisor Construction Practice Test
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Excavation and Trenching Safety Flashcards

6 cards from real STSC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Excavation and Trenching Safety flashcards as text

  1. Under OSHA 29 CFR 1926 Subpart P, at what depth does an excavation or trench require a protective system (sloping, shoring, or trench box)?

    Answer: 5 feet

    OSHA 1926.652(a)(1) requires a protective system for all excavations 5 feet or deeper in depth, except those made entirely in stable rock.

  2. What are the four soil types/classifications used in OSHA's excavation standard, and which requires the most restrictive (flattest) sloping angle?

    Answer: Stable Rock, Type A, Type B, Type C — Type C is most restrictive

    OSHA uses Stable Rock, Type A (most stable), Type B, and Type C (least stable). Type C soil requires the flattest slope — 1.5:1 (horizontal:vertical) — reflecting its instability.

  3. A competent person observing a trench wall notices vertical cracks running parallel to the trench face and a slight outward bulge in the lower portion of the wall. What do these signs indicate?

    Answer: Imminent cave-in risk — immediately remove all workers from the trench

    Vertical cracks parallel to the trench face and outward wall bulging are critical warning signs of imminent cave-in. Workers must be immediately removed and no re-entry permitted until the competent person determines it is safe.

  4. Where must excavated material (spoil) be placed relative to the edge of a trench according to OSHA 1926.651(j)(2)?

    Answer: At least 2 feet from the edge of the excavation

    OSHA 1926.651(j)(2) requires that excavated material (spoil) be placed at least 2 feet (0.61 m) from the edge of the excavation to prevent it from falling back into the trench and to reduce surcharge loading on trench walls.

  5. What is the maximum distance that a safe means of egress (ladder, steps, or ramp) must be from any worker in a trench deeper than 4 feet?

    Answer: 25 feet

    OSHA 1926.651(c)(2) requires that ladders, steps, ramps, or other safe means of egress be located within 25 lateral feet of all workers in trenches 4 feet or deeper.

  6. Before any excavation work begins, what is the REQUIRED first step under OSHA 1926.651(b)?

    Answer: Contact all underground utilities to mark or identify buried facilities

    OSHA 1926.651(b) requires that the approximate location of utilities — sewer, telephone, fuel, electric, water lines, or other underground installations — be determined before opening an excavation, and utility owners must be contacted to mark or identify installations.