excavation safety - ocflexcavation safety. 2 objectives ... design of support systems, shield...
TRANSCRIPT
![Page 1: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/1.jpg)
1
Excavation Safety
![Page 2: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/2.jpg)
2
ObjectivesTo provide students with:
An introduction to 29 CFR 1926, Subpart P-Excavation StandardAn overview of soil mechanicsAn introduction to trenching and excavation hazard recognition
![Page 3: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/3.jpg)
3
29 CFR 1926, Subpart P
1926.650• Scope, application, and definitions applicable to
this subpart
1926.651• General requirements
1926.652• Requirements for protective systems
![Page 4: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/4.jpg)
4
1926.650 Scope, Application, and Definitions
Scope and application
Definitions
Competent Person
![Page 5: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/5.jpg)
5
1926.650 Scope & Application, Definitions
Accepted engineering practicesAluminum hydraulic shoringBell-bottom pierBenchingCave-inCompetent personCross braces
Kick-outProtective systemsRampRegistered professional engineerSheetingShieldShoring
![Page 6: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/6.jpg)
6
1926.650 Scope & Application, Definitions
ExcavationFaces or sidesFailureHazardous atmospheres`
SlopingStable rockStructural rampTrench
![Page 7: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/7.jpg)
7
Definitions"Excavation" means any:
1. Man-made cut 2. Cavity 3. Trench 4. Depression in an earth surface, formed by
earth removal.
![Page 8: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/8.jpg)
8
DefinitionsConfined space is a space that, by design and/or configuration has:
1. Limited openings for entry and exit 2. Unfavorable natural ventilation 3. May contain or produce hazardous
substances4. Is not intended for continuous employee
occupancy.
![Page 9: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/9.jpg)
9
Definitions Cont. "Trench (Trench excavation)" means a narrow excavation (in relation to its length) made below the surface of the ground.
1. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m).
![Page 10: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/10.jpg)
10
Definitions Cont.
![Page 11: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/11.jpg)
11
Definitions Cont. 2. If forms or other structures are installed
or constructed in an excavation so as to reduce the dimension measured from the forms or structure to the side of the excavation to 15 feet (4.6 m) or less (measured at the bottom of the excavation), the excavation is also considered to be a trench.
![Page 12: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/12.jpg)
12
Definitions Cont.
![Page 13: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/13.jpg)
13
Definitions Cont. Accepted engineering practices are procedures that are compatible with the standard practice required of a registered professional engineer.
Adjacent structure stability refers to the stability of the foundation(s) of adjacent structures whose location may create surcharges, changes in soil conditions, or other disruptions that have the potential to extend into the failure of the excavation or trench.
![Page 14: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/14.jpg)
14
Definitions Cont.A competent persons is one who is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to eliminate them.
![Page 15: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/15.jpg)
15
Definitions Cont.A competent person must havespecific training in, and be knowledgeable about,
soils analysisthe use of protective systemsrequirements of this standard
» Preamble page 45909
![Page 16: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/16.jpg)
16
Definitions Cont.Protective systems refers to a method of protecting employees from cave-ins, material that could fall or roll from an excavation faceinto an excavation, and from the collapse of adjacent structures.
Protective systems include support systems, sloping and benching systems, shield systems, and other systems that provide the necessary protection.
![Page 17: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/17.jpg)
17
Definitions Cont.
![Page 18: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/18.jpg)
18
Definitions Cont.
![Page 19: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/19.jpg)
19
Definitions Cont.
![Page 20: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/20.jpg)
20
1926.651 - Generalrequirements
Surface encumbrancesUnderground installationsAccess and egressExposure to vehicular trafficExposure to falling loadsWarning system for mobile equipmentStability of adjacent structures
Protection of employees from loose rock or soilInspectionsFall protectionHazardous atmospheres Protection from hazards associated with water accumulation
![Page 21: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/21.jpg)
21
1926.651(c)(2) Means of egressMeans of egress from trench excavations:
1. A stairway, ladder, ramp or other safe means of egress shall be located in trench excavations that are 4 feet (1.22 mm) or more in depth.
2. A means of egress should require no more than 25 feet (7.62 m) of lateral travel for any employee to reach.
![Page 22: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/22.jpg)
22
1926.651(k)-InspectionsDaily inspections of excavations, the adjacent areas, and protective systems shall be made by a competent person for evidence of a situation that could result in:
1. Possible cave-ins 2. Indications of failure of protective systems 3. Hazardous atmospheres 4. Other hazardous conditions.
![Page 23: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/23.jpg)
23
1926.651(k)-Inspections Cont.An inspection shall be conducted by the competent person:
1. Prior to the start of work and as needed throughout the shift.
2. After every rainstorm or other hazard increasing occurrence.
3. These inspections are only required when employee exposure can be reasonably anticipated.
![Page 24: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/24.jpg)
24
1926.652 - Requirements for protective systems
Protection of employees in excavationsDesign of sloping and benching systemsDesign of support systems, shield systems, and other protective systems
Materials and equipmentInstallation and removal
![Page 25: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/25.jpg)
25
1926.652 (a)-Protection of employees in excavations
(1) Each employee in an excavation shall be protected from cave-ins by an adequate protective system designed in accordance with paragraph (b) or (c) of this section except when:
(i) Excavations are made entirely in stable rock; or(ii) Excavations are less than 5 feet (1.52 m) in depth and examination of the ground by a competent person provides no indication of a potential cave-in.
![Page 26: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/26.jpg)
26
![Page 27: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/27.jpg)
27
1926.652 (d)-Materials andequipment
(1) Materials and equipment used for protective systems shall be free from damage or defects that might impair their proper function.
![Page 28: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/28.jpg)
28
1926.652 (d)-Materials andEquipment Cont.
(3) When material or equipment that is used for protective systems is damaged, a competent person shall examine the material or equipment and evaluate its suitability for continued use.
![Page 29: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/29.jpg)
29
1926.652 (d)-Materials andEquipment Cont.
If the competent person cannot assure the material or equipment is able to support the intended loads or is otherwise suitable for safe use.
1. Such material or equipment shall be removed from service.
2. Such material or equipment shall be evaluated and approved by a registered professional engineer before being returned to service.
![Page 30: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/30.jpg)
30
Worker Protection Systems
Appendix A• Soil Classification
Appendix B• Sloping & Benching
Appendix C• Timber Shoring
Appendix D• Aluminum Hydraulic Shoring
![Page 31: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/31.jpg)
31
![Page 32: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/32.jpg)
32
Soil Testing
![Page 33: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/33.jpg)
33
OBJECTIVES
Provide the student with:• A brief overview of 29 CFR 1926 Subpart P
Excavation Standard• A Brief Introduction into Soil mechanics• A Brief overview of tests they can use in
determining soil conditions
![Page 34: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/34.jpg)
34
Overview: Soil Mechanics
Soil Mechanics
A number of stresses and deformities can occur in an open cut or trench.
For example, increases and decreases in moisture content can adversely affect the stability of a trench or excavation.
![Page 35: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/35.jpg)
35
Soil Mechanics Cont.Following are some of the more frequently identified causes of trench failure.
Tension Cracks: Usually form at a horizontal distance of .5 to .75 times the depth of the trench, measured from the top of the vertical face of the trench.
Sliding or Sluffing: May occur as a result of tension cracks.
![Page 36: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/36.jpg)
36
![Page 37: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/37.jpg)
37
Soil Mechanics Cont.Toppling: In addition to sliding, tension cracks can cause toppling.
1. Toppling occurs when the trench’s vertical face shears along the tension crack line and topples into the excavation.
![Page 38: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/38.jpg)
38
![Page 39: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/39.jpg)
39
Soil Mechanics Cont.Subsidence and Bulging:
1. An unsupported excavation can create unbalanced stress in the soil, which in turn, causes subsidence at the surface and bulging of the vertical face of the trench.
2. If uncorrected, this condition can cause face failure and entrapment of workers in the trench.
![Page 40: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/40.jpg)
40
Soil Mechanics Cont.Heaving or Squeezing:
Bottom heaving or squeezing is caused by the downward pressure created by the weight of adjoining soil. This pressure causes a bulge in the bottom of the cut.
Heaving and squeezing can occur even when shoring or shielding has been properly installed.
![Page 41: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/41.jpg)
41
Soil Mechanics Cont.Boiling is evidenced by an upward water flow into the bottom of the cut.
1. A high water table is one cause of boiling.
Boiling produces a “quick” condition in the bottom of the cut, and occur even when shoring or trench boxes are used.
![Page 42: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/42.jpg)
42
![Page 43: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/43.jpg)
43
Soil - CompositionWhat is Soil ?
![Page 44: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/44.jpg)
44
![Page 45: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/45.jpg)
45
Soils - TypesGravel
larger than 2 millimetersSand
Smaller than 2 millimeters but larger than 0.075 millimeters
SiltSmaller than 0.075 millimeters but larger than 0.002 millimeters
ClaySmaller than 0.002 millimeters
![Page 46: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/46.jpg)
46
Determination of Soil Type
OSHA categorizes soil and rock deposits into four types. Each type is briefly described below.
Stable rock is natural solid mineral matter that can be excavated with vertical sides and remain intact while exposed.
![Page 47: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/47.jpg)
47
ROCK!
![Page 48: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/48.jpg)
48
Black Pine Mine Slide - Idaho
![Page 49: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/49.jpg)
49
Determination of Soil Type
Type A soils are cohesive soils with an unconfined compressive strength of 1.5 tons per square foot or greater.
Examples of type A soils are: clay, silty clay,sandy clay, clay loam, and in some cases siltyclay loam and sandy clay loam.
![Page 50: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/50.jpg)
50
Determination of Soil Type
No soil is type A if it is fissured, is subject to vibration of any type, has previously been disturbed, is part of a sloped, layered system where the layers dip into the excavation on a slope of 4H to 1V or greater, or has seeping water.
![Page 51: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/51.jpg)
51
Determination of Soil Type
Type B soils are cohesive soils with an unconfined compressive strength greater than 0.5 tons per square foot, but less than 1.5 tons per square foot.
Examples are: angular gravel, silt, silt loam, previously disturbed soils unless otherwise classified as type C soil.
![Page 52: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/52.jpg)
52
Determination of Soil Type
Soils that meet the unconfined compressive strength or cementation requirements of type A soils but are fissured or subject to vibration; dry unstable rock; layered systems sloping into the trench at a slope less than 4H to 1V ( only if the material would be classified as a type B soil).
![Page 53: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/53.jpg)
53
Determination of Soil Type
Type C soils are cohesive soils with an unconfined compressive strength of 0.5 tons per square foot or less and include granular soils such as gravel, sand and loamy sand, submerged soil, soil from which water is freely seeping, and submerged rock that is not stable.
![Page 54: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/54.jpg)
54
Determination of Soil Type
Type C soils also include in this classification material in a sloped, layered system where the layers dip into the excavation or have a slope of 4H to 1V or greater.
![Page 55: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/55.jpg)
55
1 cubic ft.1 cubic ft.
![Page 56: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/56.jpg)
56
Soils - Volume
1 cubic ft.
= 83 lbs.
= 31 lbs.
Total 31 + 83 = 114
![Page 57: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/57.jpg)
57
Soils - Cubic Yard Weight
1 cubic yd.
27 X 114 = 3078 lbs.
Average soil
![Page 58: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/58.jpg)
58
![Page 59: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/59.jpg)
59
Field TestsDocumenting field testsSedimentationRibbonTorvanePocket PenetrometerThumb imprint
![Page 60: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/60.jpg)
60
Documenting Field Tests
OSHA
![Page 61: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/61.jpg)
61
Documenting Field Test (continued)
All TestsRepresentativesampleSpoil pileInside the trenchDiagramSite mapRecord readingSoil rating
![Page 62: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/62.jpg)
62
![Page 63: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/63.jpg)
63
1/4 1/4
1/4 1/4
1/4 1/4
1/4 1/4
1/4 1/4
1/4 1/4
Mix it - Quarter it
Mix it - Quarter it
•Ribbon test•Wet shaking•Sedimentation TestSoil sample
Mix it - Quarter it
![Page 64: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/64.jpg)
64
Documenting Field Test (continued)
•Torvane•Pocket penetrometer•Thumb imprint
![Page 65: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/65.jpg)
65
Test # 1 - Field Sedimentation Test
Determines sand content
Used only on sandy soils
Sample taken from the spoil pile
Representative of soil in the excavation
![Page 66: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/66.jpg)
66
Field Sedimentation Test (Continued)
Fill glass jar 5 inches of water on top of soil1 1/2 inches of soilFlat bottom container - at least 7 inches high
![Page 67: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/67.jpg)
67
Field Sedimentation Test (Continued)
Place lid on jar and shake
Set jar downRotate slightlyLarger particles settle out immediatelyWait 30 seconds Mark jarSilt after several minutesFine clays in an hourMake second mark
![Page 68: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/68.jpg)
68
![Page 69: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/69.jpg)
69
Test # 2 - The Ribbon Test
![Page 70: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/70.jpg)
70
The Ribbon Test
Run only on that part of the soil which
passes # 40 sieveTest shows clay materialRun on disturbed soilRepresentative sample from spoil pile
![Page 71: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/71.jpg)
71
The Ribbon Test (continued)
Mix soil + water to make into plastic massRoll mass into cylindrical shape 1/2 to 3/4 inch diameterLay across palm of hand Press between thumb and second joint of index finger
![Page 72: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/72.jpg)
72
The Ribbon Test (continued
Pass through thumb
Squeeze until it takes the shape of a 1/8 to 1/4 inch thick strip Allow to hang freely from hand
![Page 73: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/73.jpg)
73
The Ribbon Test (continued)
Clay loam will barely ribbon and break easilyClay = relatively long ribbon 6 to 8 inches or moreMore clay = longer and stronger ribbonSilt has tendency to produce short ribbon with broken appearance
![Page 74: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/74.jpg)
74
Penciling
![Page 75: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/75.jpg)
75
Test # 3 Torvane Shear Test
![Page 76: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/76.jpg)
76
Torvane Shear
Designed to be used on saturated cohesive clay soilVanes are inserted into soilTwist and shear soil at base and around circumference of vanes
![Page 77: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/77.jpg)
77
Torvane Shear Test (continued)
Select fresh clod or block of undisturbed soil from spoil pileCut a smooth surface on the clodInsert vanes of device into the soilRetract vanes to show foot imprintSet indicator at zeroHold device firmly against soil and twist in clockwise manner until soil fails in shear
![Page 78: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/78.jpg)
78
![Page 79: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/79.jpg)
79
Test # 4 - Pocket Penetrometer
![Page 80: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/80.jpg)
80
Pocket PenetrometerRead the unconfined compressive strength at bottom of the red slip ringThe reading may be 2.0 tons per square foot shear strengthWhich indicate the boundary between stiff and very stiff
![Page 81: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/81.jpg)
81
Pocket Penetrometer TestDevice is designed to work on saturated clay soilMeasures unconfined compressive strength of soilTwice the value of shear strength of same soilNote machine ring about a quarter of an inch
![Page 82: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/82.jpg)
82
Pocket Penetrometer(Continued)
Push red ring on the barrel all the way toward the handlePush shaft into the soil up to the red ringHold barrel so as to not to interfere with the spring inside the barrelNOTE slip ring moved on the barrel as barrel was pushed back into the handle
![Page 83: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/83.jpg)
83
![Page 84: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/84.jpg)
84
Hazard Recognition Slides
![Page 85: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/85.jpg)
85
![Page 86: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/86.jpg)
86
![Page 87: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/87.jpg)
87
![Page 88: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/88.jpg)
88
![Page 89: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/89.jpg)
89
![Page 90: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/90.jpg)
90
![Page 91: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/91.jpg)
91
![Page 92: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/92.jpg)
92
![Page 93: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/93.jpg)
93
![Page 94: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/94.jpg)
94
![Page 95: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/95.jpg)
95
![Page 96: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/96.jpg)
96
![Page 97: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/97.jpg)
97
![Page 98: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/98.jpg)
98
![Page 99: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/99.jpg)
99
![Page 100: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/100.jpg)
100
![Page 101: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/101.jpg)
101
![Page 102: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/102.jpg)
102
![Page 103: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/103.jpg)
103
![Page 104: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/104.jpg)
104
![Page 105: Excavation Safety - OCFLExcavation Safety. 2 Objectives ... Design of support systems, shield systems, ... Each employee in an excavation shall be protectedapps.ocfl.net/.../public_safety/risk/Excavation_Safety_Slides.pdf ·](https://reader033.vdocument.in/reader033/viewer/2022052708/5a706d667f8b9ab1538bf106/html5/thumbnails/105.jpg)
105