Trenching and Excavation Standards

Terms (61)

1. 01

   What is required for excavations that are 5 feet or deeper?

   Protective systems must be used to prevent cave-ins, as determined by a competent person. (29 CFR 1926.652(a)(1))

2. 02

   How often must a competent person inspect excavations?

   At the start of each shift, after every rainstorm or other event that could increase hazards, and as needed throughout the shift. (29 CFR 1926.651(k)(1))

3. 03

   Under 29 CFR 1926.651, what defines a competent person for excavations?

   One who is capable of identifying existing and predictable hazards in excavations and who has authorization to take prompt corrective measures. (29 CFR 1926.651(a))

4. 04

   What protective system is required in unstable soil for trenches 20 feet or deeper?

   A registered professional engineer must design the protective system. (29 CFR 1926.652(b))

5. 05

   When must employees be protected from excavated materials in a trench?

   Excavated or other materials must be kept at least 2 feet from the edge of excavations. (29 CFR 1926.651(j)(2))

6. 06

   What is the maximum distance allowed between a worker and a means of egress in an excavation?

   No more than 25 feet of lateral travel for employees in excavations 4 feet or more in depth. (29 CFR 1926.651(c)(2))

7. 07

   Under 29 CFR 1926.652, what must be done if water is accumulating in an excavation?

   Employees must be removed from the hazardous area, and measures must be taken to control the water and ensure the stability of the excavation. (29 CFR 1926.652(a)(2))

8. 08

   What type of soil classification requires the most protective measures in excavations?

   Type C soil, which has an unconfined compressive strength of 0.5 tsf or less, requires the most stringent protection. (29 CFR 1926.652, Appendix A)

9. 09

   How must ladders be used in excavations?

   Ladders must be provided for access and egress in excavations 4 feet or more in depth, and they must extend 3 feet above the excavation edge. (29 CFR 1926.651(c)(1) and (2))

10. 10

    What is required before starting excavation work near underground utilities?

    The location of utilities must be determined and marked, and protective measures must be taken to avoid damage. (29 CFR 1926.651(b))

11. 11

    In what situation must a trench box be used in an excavation?

    When protective systems are needed to shield employees from cave-ins in trenches, such as in unstable soil. (29 CFR 1926.652(c))

12. 12

    What must be done if an excavation is subject to vibration from traffic or equipment?

    Additional precautions must be taken to prevent cave-ins, as evaluated by a competent person. (29 CFR 1926.651(a)(1))

13. 13

    Under 29 CFR 1926.651, what defines Type B soil?

    Soil that includes cohesive soil with an unconfined compressive strength greater than 0.5 tsf but less than 1.5 tsf, or granular cohesionless soils like angular gravel. (29 CFR 1926.652, Appendix A)

14. 14

    What is the first step when planning an excavation?

    Evaluate soil conditions and potential hazards to determine the appropriate protective system, as required by a competent person. (29 CFR 1926.651(c))

15. 15

    A worker notices a crack in the wall of a trench; what should they do?

    Immediately exit the trench and notify a competent person to assess and stabilize the area. (29 CFR 1926.651(k)(2))

16. 16

    What maximum slope is allowed for Type B soil in excavations?

    :1 (45 degrees), but it must be determined by a competent person based on soil analysis. (29 CFR 1926.652, Appendix B)

17. 17

    How should spoil piles be managed in excavation sites?

    They must be stored at least 2 feet from the edge of the excavation to prevent cave-ins. (29 CFR 1926.651(j)(2))

18. 18

    What training is required for workers in excavations?

    Training on the recognition of hazards associated with excavations and the use of protective systems, provided by a competent person. (29 CFR 1926.651(a))

19. 19

    Under 29 CFR 1926.652, when is shoring required?

    In excavations where sloping or benching is not possible, to prevent cave-ins by supporting the sides. (29 CFR 1926.652(a))

20. 20

    What must be inspected daily in an excavation site?

    The excavation, adjacent areas, and protective systems must be inspected by a competent person for hazards. (29 CFR 1926.651(k)(1))

21. 21

    What is a competent person's role in excavation work?

    To identify hazards, ensure safe conditions, and authorize entry or corrective actions in excavations. (29 CFR 1926.651)

22. 22

    How deep must an excavation be to require a protective system?

    feet or greater, unless the excavation is made entirely in stable rock. (29 CFR 1926.652(a)(1))

23. 23

    Before entering a trench, what must workers ensure?

    That a safe means of access and egress is available and that the trench has been inspected by a competent person. (29 CFR 1926.651(c))

24. 24

    A trench has standing water; what is the appropriate response?

    Stop work, remove employees from the area, and implement measures to remove the water and stabilize the trench. (29 CFR 1926.652(a)(2))

25. 25

    Under 29 CFR 1926.651, what is required for access in excavations?

    A safe means of egress, such as ladders, must be provided within 25 feet of travel for employees. (29 CFR 1926.651(c)(2))

26. 26

    What is the definition of an excavation under OSHA standards?

    Any man-made cut, cavity, trench, or depression in the earth's surface formed by earth removal. (29 CFR 1926.650(b))

27. 27

    What minimum clearance is needed around underground installations during excavation?

    At least 2 feet, or the width of the installation if greater, to avoid contact. (29 CFR 1926.651(b)(4))

28. 28

    What procedure must follow if a cave-in occurs?

    Evacuate all workers, assess the site, and implement corrective measures before re-entry, as directed by a competent person. (29 CFR 1926.651(k))

29. 29

    In a scenario with overhead power lines near an excavation, what must be done?

    Maintain a safe distance and ensure no contact occurs, with precautions determined by a competent person. (29 CFR 1926.651(i))

30. 30

    What is required for the design of protective systems in excavations?

    They must be designed by a registered professional engineer for excavations 20 feet or deeper. (29 CFR 1926.652(b))

31. 31

    How often should atmospheric testing occur in excavations?

    Before employees enter and as necessary during occupancy if conditions might change. (29 CFR 1926.651(g))

32. 32

    What defines Type A soil in excavations?

    Cohesive soil with an unconfined compressive strength of 1.5 tsf or greater, such as clay. (29 CFR 1926.652, Appendix A)

33. 33

    What must be done if an excavation is left open overnight?

    It must be effectively protected with barriers or covers to prevent accidental entry. (29 CFR 1926.651(l))

34. 34

    Under 29 CFR 1926.652, what options exist for trench protection?

    Sloping, benching, shoring, or shielding, as selected based on soil type and depth. (29 CFR 1926.652(a))

35. 35

    A worker feels the ground shifting in a trench; what should they do?

    Exit the trench immediately and report to a competent person for evaluation. (29 CFR 1926.651(k))

36. 36

    What is the maximum allowable height for unsupported vertical sides in Type C soil?

    Not applicable; Type C requires sloping or other protection at any depth over 4 feet. (29 CFR 1926.652, Appendix B)

37. 37

    What documentation is needed for excavation work?

    A competent person must document inspections and any corrective actions taken. (29 CFR 1926.651(k))

38. 38

    Before using a trench box, what must be verified?

    That it is installed and used according to the manufacturer's specifications and site conditions. (29 CFR 1926.652(c))

39. 39

    In what conditions must excavations be shored?

    When the sides could cave in, based on soil analysis by a competent person. (29 CFR 1926.652(a))

40. 40

    What is required if an excavation is near a structure?

    Underpinning or other support must be provided to prevent damage or collapse. (29 CFR 1926.651(j))

41. 41

    Under 29 CFR 1926.650, what hazards must be evaluated in excavations?

    Cave-ins, water accumulation, falls, and hazardous atmospheres, among others. (29 CFR 1926.650)

42. 42

    What protective equipment is mandatory in excavations?

    Hard hats, safety harnesses if needed, and other PPE as determined by hazards present. (29 CFR 1926.651(b))

43. 43

    How should employees be trained on excavation hazards?

    By a competent person, covering recognition of hazards and emergency procedures. (29 CFR 1926.651(a))

44. 44

    What is the procedure for exiting an unsafe excavation?

    Use the designated means of egress quickly and notify the competent person. (29 CFR 1926.651(c))

45. 45

    A trench exceeds 20 feet in depth; what additional requirement applies?

    The protective system must be designed by a registered professional engineer. (29 CFR 1926.652(b))

46. 46

    What must be included in an excavation site safety plan?

    Assessment of soil, protective systems, and emergency procedures, as overseen by a competent person. (29 CFR 1926.651)

47. 47

    Under 29 CFR 1926.651, when is benching allowed?

    In certain stable soils, as a method to prevent cave-ins by stepping back the walls. (29 CFR 1926.652(b))

48. 48

    What atmospheric hazards must be tested in excavations?

    Oxygen deficiency, flammable gases, and toxic substances before entry. (29 CFR 1926.651(g))

49. 49

    What is the role of barriers in excavation sites?

    To warn and prevent unauthorized entry into hazardous areas. (29 CFR 1926.651(l))

50. 50

    In a rainy condition, what must be checked in an excavation?

    The competent person must inspect for water accumulation and soil stability. (29 CFR 1926.651(k))

51. 51

    What defines a trench under OSHA?

    A narrow excavation deeper than it is wide, not wider than 15 feet. (29 CFR 1926.650(b))

52. 52

    How must materials be stored near excavations?

    At a safe distance to avoid overloading the edge, as determined by a competent person. (29 CFR 1926.651(j))

53. 53

    What emergency response is needed for a cave-in incident?

    Immediate evacuation and rescue procedures, coordinated by trained personnel. (29 CFR 1926.651)

54. 54

    Under 29 CFR 1926.652, what factors affect sloping requirements?

    Soil type, depth, and environmental conditions, as detailed in appendices. (29 CFR 1926.652)

55. 55

    What must be done if utilities are encountered during excavation?

    Stop work and contact the utility owner for safe disconnection or relocation. (29 CFR 1926.651(b))

56. 56

    What is required for the stability of excavation walls?

    They must be sloped, shored, or shielded based on soil classification. (29 CFR 1926.652(a))

57. 57

    A competent person finds unstable soil; what action follows?

    Implement immediate protective measures or evacuate the area. (29 CFR 1926.651(k))

58. 58

    What daily records must be kept for excavations?

    Inspection results and any hazards identified by the competent person. (29 CFR 1926.651(k))

59. 59

    Under 29 CFR 1926.650, what general requirements apply to all excavations?

    Utility locations must be determined, and surface encumbrances removed. (29 CFR 1926.650(a))

60. 60

    What protective measures are needed for vehicular traffic near excavations?

    Warning signs, barricades, and flag persons to prevent accidents. (29 CFR 1926.651(i))

61. 61

    What is the minimum training for a competent person in excavations?

    Knowledge of soil analysis, protective systems, and hazard recognition. (29 CFR 1926.651(a))