Excavations (OSHA 10-Hour Construction Outreach)

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1. Slide 1

   Excavations

   • 10-Hour Construction Outreach
2. Slide 2

   Excavations

   • Source of photos: NIOSH /John Rekus
3. Slide 3

   Excavations

   • Lesson Overview
   • Role of Competent Person
   • Excavation Hazards
   • Protection from Cave-ins
   • Protection from other Excavation Hazards
   • Employer Requirements
4. Slide 4

   Role of Competent Person

   • Required training and knowledge
   • Soil classification
   • Use of protective systems
   • OSHA’s requirements for excavation
   • Able to identify hazards and have the authority to eliminate hazards
5. Slide 5
   • This competent person is inspecting the excavation, surroundings and protective system. If a hazard is identified, they will remove the worker and take prompt corrective action.
   • Source of photo: OTIEC Chabot Las Positas
6. Slide 6

   Excavation Hazards

   • This is a very dangerous situation!
   • Cave-ins
   • Falls
   • Falling Loads
   • Hazardous Environment Mobile Equipment
   • Underground Utilities
   • Source of photo: OSHA
7. Slide 7

   Cave-Ins

   • Greatest hazard
   • It is natural for a trench to try to fill itself
   • One cubic foot of soil weighs between 90-130 lbs.
   • It will entrap, bury, or otherwise injure you
8. Slide 8

   They Both Died

   • A crew was installing conduit in an 8’ deep by 2’ wide trench.
   • The trench collapsed.
   • Two workers were buried.
   • They both died!
   • Source of photo: CDC/NIOSH/FACE
9. Slide 9

   Protection is Required

   • Never enter an unprotected trench that is 5 or more in depth
   • The competent person must first choose and implement a protective system
   • Even excavations less than 5 feet deep need to be deemed safe by the competent person
   • Cave-ins can happen without warning
   • This 6 foot deep vertical-sided, unprotected trench is dangerous!
   • Source of photo: OTIEC NRC WVU
10. Slide 10

    Protective Systems

    • Support/shoring systems
    • Sloping and benching
    • Shielding systems (trench boxes)
    • Shoring
    • Sloping
    • Shielding
11. Slide 11

    Support/shoring Systems

    • Source of photos: NIOSH /John Rekus
12. Slide 12

    The Theory of Shoring

    • Shoring prevents cave-ins
    • Shoring, if designed and installed correctly, prevents movement of the excavated wall.
    • In order for the shoring to do its job, you must stay within the protection of the shoring even when entering and exiting
13. Slide 13

    Improper Shoring

    • Click to add Text
    • Make-shift, improperly designed shoring does little other then provide a false sense of security!
    • Source of photos: OSHA
14. Slide 14

    Sloping and Benching

    • This slope is safe for any soil classification!
    • Is this a 1 ½ to 1 slope?
15. Slide 15

    The Theory of Sloping

    • Sloping prevents cave-ins
    • Sloping, if done correctly, removes the risk of cave-ins by sloping the soil of the trench back from the trench bottom
    • Source of photo: OTIEC NRC WVU
16. Slide 16

    Shield System

    • How many hazards can you find ?
    • Source of photo: OSHA
17. Slide 17

    The Theory of Shielding

    • Trench shields and boxes, if installed correctly, are designed to protect workers from the forces of a cave-in
    • In order for the shield to do its job, you must stay within the protection of the shield even when entering and exiting
18. Slide 18

    Falls

    • Safe Alternative
    • Source of photos: OSHA
19. Slide 19

    Adjacent Structures

    • Structures become unstable when earth next to them is removed
    • For your safety, they must be supported
    • A competent person must ensure precautions are implemented.
20. Slide 20

    Underground Utilities

    • As required, this worker’s employer used their state’s one call system to locate under ground utilities before breaking ground. Now he is hand digging to find the exact location.
    • Source of photo: OSHA
21. Slide 21

    Spoil Pile

    • Minimum
    • Source of photo: OSHA
22. Slide 22

    Mobile Equipment

    • Safe Alternative
    • Source of photos: OSHA
23. Slide 23

    Vehicular or Traffic Hazards

    • Source of photos: OSHA
24. Slide 24

    Falling Loads

    • Do you see any other hazards?
    • Source of photo: OSHA
25. Slide 25

    Hazardous Atmospheres

    • Source of photo: OSHA
26. Slide 26

    Water Accumulation

    • Source of photos: OSHA
27. Slide 27

    Access/Egress

    • Source of photo: OSHA
28. Slide 28

    Ladders

29. Slide 29

    Hard Hats

    • Working below grade, overhead hazards exist
    • Hard hats must be worn in excavations because of overhead hazards
    • Source of photo: OSHA
30. Slide 30

    Responsibilities: Employer

    • Employers must:
    • preplan the work and use the one-call system to identify underground utilities
    • protect you from cave-ins and other excavation-related hazards
    • inspect the excavation at least daily and throughout the shift as needed
    • take prompt corrective action when a hazard is identified
    • respond to and correct hazards pointed out by you, the worker
31. Slide 31

    Responsibilities: Employer

    • Employers must:
    • make sure a ladder is within 25’ of your work area when deeper than 4’
    • keep excavated dirt, rocks and other materials back 2’ from the excavation’s edge
    • Test and monitor the air within the trench in areas suspect to atmospheric hazards
32. Slide 32

    Responsibilities: You

    • You must:
    • work defensively
    • Follow you company’s excavation and trenching safety rules
    • correct the hazards you are able to correct
    • report to your supervisor the hazards you are unable to correct
33. Slide 33

    Case Study

34. Slide 34

    Hazard Recognition

    • Identify hazards and what should be done
    • Source of photos: OSHA
35. Slide 35

    Hazard Recognition

    • Identify hazards and what should be done
    • Source of photos: OSHA
36. Slide 36

    Hazard Recognition

    • Identify hazards and what should be done
    • Source of photo: OSHA
37. Slide 37

    Always Remember

    • Never enter a trench 5’ or greater in depth unless a protective system is in place.
    • Trenches less than 5’ deep still require the competent person’s “OK”
    • If a trench box or shoring is used, never leave its protection while in the trench
38. Slide 38

    Knowledge Check

    • What is the minimum distance that excavated materials, tools, and other supplies be kept back from the excavation’s edge?
    • a. 1 foot
    • b. 2 feet
    • c. 7.5 feet
    • d. 25 feet
    • b. 2 feet
39. Slide 39

    Knowledge Check

    • At what depth must a ladder, ramp, steps, or runway be present for quick worker exit:
    • a. 4 feet
    • b. 5 feet
    • c. 10 feet
    • d. It is never required
    • a. 4 feet
40. Slide 40

    Knowledge Check

    • What is the greatest hazard facing a worker while working in a trench:
    • a. Hazardous atmospheres
    • b. Falls
    • c. Cave-ins
    • d. Falling Objects
    • c. Cave-ins
41. Slide 41

    Knowledge Check

    • Unless made in entirely stable rock, at what depth is a protective system required for a trench:
    • a. Any depth if the competent person says so.
    • b. 5 feet deep and greater
    • c. Both a and b
    • d. A protective system is never required in trenches
42. Slide 42

    Excavations in Construction

    • Questions?