1. Confined Spaces and Trenching A PowerPoint Presentation keyed to Chapter 6 of Materials for Teaching Agricultural Safety in the College Classroom by Carol J. Lehtola, PhD, and Charles M. Brown Book and more presentations in this series are available on the National Ag Safety Database, www.nasdonline.org

2. OSHA Definition of Confined Space “... a space that 1. Is large enough and so configured that an employee can bodily enter and perform assigned work; and 2. Has limited or restricted means for entry or exit; and 3. Is not designed for continuous human occupancy. Confined Spaces and TrenchingSlide 6.1

3. Permit-Required Confined Space for General Industry “All employers must provide training to employees who work in confined spaces so they may acquire the understanding, knowledge, and skills necessary for the safe performance of their duties.” Employee’s responsibilities and procedures Confined Spaces and TrenchingSlide 6.2

4. Confined Spaces in Agriculture Examples Manure pits Hoppers and silos Fertilizer storage tanks Conveyor enclosures Spray tanks Confined Spaces and TrenchingSlide 6.3

5. Confined Space Examples Sewers Wells Trenches Excavations Confined Spaces and TrenchingSlide 6.4

6. Reasons for Entry Cleaning Inspection Maintenance Installation Repairs (can include welding) Reading meters, gauges, etc. Rescue of workers who are injured or overcome Confined Spaces and TrenchingSlide 6.5

7. Atmospheric Hazards Oxygen deficient Oxygen enriched Toxic atmospheres Irritating atmospheres Confined Spaces and TrenchingSlide 6.6

8. Physical Hazards Confined Spaces and TrenchingSlide 6.7 Mechanical equipment Electrical Fluids Thermal condition (extremes in hot or cold) Engulfment by solid materials (e.g., grain, soil)

9. Psychological Factors Claustrophobia Other “Phobias” – Heights – Falling Confined Spaces and TrenchingSlide 6.8

10. Often Multiple Deaths Due to Unsuccessful Rescue Attempts Confined Spaces and TrenchingSlide 6.9

11. Confined Spaces and TrenchingSlide 6.10...But I Don’t Dig Ditches... install water lines... septic tank or well problems... soils judging teams (FFA)... archaeology... rescue workers or passers-by

12. Soil Stability Factors Soil type Depth of cut Water content of soil Changes due to weather and climate Superimposed loads Vibrations Previously dug soil Confined Spaces and TrenchingSlide 6.11

13. Protective Measures Trench boxes Shoring Sloping Confined Spaces and TrenchingSlide 6.12

14. OSHA Requirement More than 5 ft in depth shall be shored, laid back to a stable slope, or some other equivalent means of protection shall be provided where employees may be exposed to moving ground or cave-ins. Trenches <5 ft in depth shall also be effectively protected when examination of the ground indicates hazardous ground movement may be expected Confined Spaces and TrenchingSlide 6.13

15. Weight of Soil 1 cubic foot of soil weighs approximately 120 pounds Confined Spaces and TrenchingSlide 6.14