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Excavation and Trenching Safety Flashcards

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

Read the first 7 Excavation and Trenching Safety flashcards as text

  1. What action must be taken before an excavation is entered each day or after a rainstorm?

    Answer: Have a competent person inspect for hazardous conditions

    OSHA 1926.651(k) requires a competent person to inspect excavations daily and after any event that could increase hazard potential, such as rain.

  2. Which shoring system uses vertical members (uprights) driven or placed against trench walls, held by walers and cross braces?

    Answer: Timber shoring

    Timber shoring uses vertical uprights, horizontal walers, and cross braces to support trench walls against collapse.

  3. Under what circumstance may workers enter an unprotected excavation less than 5 feet deep?

    Answer: Only when a competent person determines there is no cave-in hazard

    OSHA 1926.652(a) allows excavations under 5 feet to go unprotected only if a competent person examines the ground and finds no cave-in potential.

  4. Fissured soil discovered during excavation typically indicates what type of soil classification?

    Answer: Type B or C depending on other factors

    Fissured soil is excluded from Type A classification and may be Type B or Type C depending on its other properties and conditions.

  5. Which utility locating service must be contacted before excavation begins in the United States?

    Answer: 811 (Call Before You Dig)

    Federal law requires contractors to contact 811 (the national call-before-you-dig number) to have underground utilities marked before any excavation.

  6. A trench box (shield) used in an excavation must be:

    Answer: Designed or approved by a registered professional engineer

    OSHA 1926.652(c)(3) requires trench shields to be designed by a registered PE or to meet OSHA tabulated data to ensure they can withstand expected loads.

  7. What is the maximum spacing allowed between cross braces in a timber shoring system for a trench in Type C soil, per OSHA Appendix C tables?

    Answer: Tables vary by depth and soil type — no single maximum applies universally

    OSHA Appendix C timber shoring tables specify brace spacing based on the combination of trench depth and soil type, so a universal single maximum does not apply.