Practice Test GeeksCHST - Construction Health and Safety Technician Practice Test
← All CHST Flashcard Decks

Excavation and Trenching Safety Flashcards

6 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 6 Excavation and Trenching Safety flashcards as text

  1. Under OSHA 1926.652, what is the maximum allowable slope for Type C soil when using the sloping method of protection?

    Answer: 1½H:1V (34 degrees from horizontal)

    For Type C soil, the least stable classification, OSHA requires a maximum slope of 1½H:1V (1.5 feet horizontal for every 1 foot vertical), which equals approximately 34 degrees from horizontal.

  2. What is a 'trench shield' (trench box), and what is its primary limitation compared to hydraulic shoring?

    Answer: A structure that protects workers from cave-in material but does NOT prevent the trench wall from collapsing

    A trench shield (trench box) protects workers by shielding them from falling cave-in material. Unlike hydraulic shoring, it does not apply pressure to the trench walls and does not prevent the trench wall from collapsing outside the box.

  3. Under OSHA 1926.651(h), how must water accumulation in an excavation be controlled?

    Answer: Water must be removed by pumping or diverting, and work must stop when water accumulates to hazardous levels until the competent person determines it is safe to proceed

    OSHA 1926.651(h) requires that surface water or water run-off be controlled, that workers not work in accumulated water unless adequate precautions are taken, and that all water control measures be directed by the competent person.

  4. How often must a competent person inspect excavations under OSHA 1926.651(k)?

    Answer: Daily and after any event that could change conditions, such as rain, freezing temperatures, or vibration from nearby equipment

    OSHA 1926.651(k)(1) requires a competent person to inspect excavations prior to each work shift, after rainstorms or other hazard-increasing events, and as needed throughout the shift.

  5. What is the correct soil classification for a trench in soil that is granular (sand), submerged, and has water freely seeping through it?

    Answer: Type C — the least stable classification

    Submerged granular soil with free water seepage meets the definition of Type C soil, the least stable classification requiring the most conservative protective system.

  6. Under OSHA 1926.652(c), what is the key requirement for the design of a timber shoring system used as an excavation protective system?

    Answer: It must be designed by a registered professional engineer or meet the tabulated data in OSHA Appendix C to Subpart P

    Timber shoring systems must either be designed by a registered professional engineer or comply with the tabulated data provided in OSHA Appendix C to Subpart P, which gives timber sizes and spacing for various excavation depths and soil types.