Published on January 18, 2008
Excavations: Excavations Subpart P One-hour Why the Training?: People die in excavations! See Fatal Facts Regulations 29 CFR 1926, Subpart P Why the Training? What We Will Cover: What We Will Cover Regulations Competent Person Qualifications Responsibilities Hazards of Excavations What We Will Cover: What We Will Cover Soil Classifications Protective Systems Sloping Shoring Inspections Emergency Response Regulations: Regulations 29 CFR 1926 Subpart P - Excavations Appoint Competent Person Soil evaluations by Competent Person Daily Inspections by Competent Person Shoring and sloping evaluations by Competent Person Stop Work Authority of Competent Person Competent Person: Competent Person "Competent person" means 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 take prompt corrective measures to eliminate them. Competent Person: Competent Person Qualifications Knowledge of soils and soil classification Understands design and use of protective systems Ability to recognize and test hazardous atmospheres Documented training Prior excavation experience Competent Person: Competent Person Responsibilities Site safety briefings on excavation safety Daily excavation inspections More frequent if conditions change (e.g. freeze/thaw, rain, vibration) Physically located at the excavation STOP WORK AUTHORITY!!! Excavation Hazards: Excavation Hazards Hazardous atmospheres Water accumulation Adjacent structures Loose rock or soil Falls Cave-in Surface encumbrances Utilities Access/Egress Vehicle traffic Falling loads Mobile equipment Surface Encumbrances: Surface Encumbrances Need to be removed or supported e.g. fencing, piping, structure, materials Utilities: Utilities Underground Locate prior to digging Certify deactivation Protect, support, or remove Utilities: Utilities Aboveground De-energize or Isolation from power lines Access/Egress : Access/Egress Note: Poor housekeeping --- # 1 cause of slips, trips and falls on construction projects Debris kept cleared from work areas Mark hazards Barricade or cover holes Egress provided- 25’ travel distance ladders ramps stairs Vehicle Traffic: Vehicle Traffic Traffic Control Traffic Safety Vests Exposure to Falling Loads: Exposure to Falling Loads No work under loads Operators remain in cab Mobile Equipment: Mobile Equipment Warning system Barricades Hand signals Mechanical signals Stop logs Grade away from excavation Hazardous Atmospheres: Hazardous Atmospheres Test @ 4’ if suspected LEL Oxygen CO H2S Petroleum Other toxics Ventilation: Ventilation Displace hazardous gases and vapors Considerations Heavier than air or lighter than air contaminant Exhausting or blowing in Volume/time required to lower concentrations to acceptable levels Water Accumulation: Water Accumulation Protection from hazards associated with water accumulation Protection against cave-in Water removal (pumping) Run-off protection Consider temporary shut-off of water lines Adjacent Structures: Adjacent Structures Ensure structure stability Shoring Bracing Underpinning Or evaluation by P.E. Loose Rock and Soil: Loose Rock and Soil Protection of employees from loose rock or soil Scaling Protective barriers Placing material at least 2’ from edge No work on slopes above workers Fall Protection: Fall Protection Any surface 6 feet or more above a lower level shall be protected by: walkways with guardrail systems personal fall arrest systems Other options include: warning lines systems safety monitoring systems Cave-in: Cave-in Protection from cave-in requires a systematic approach including: Soil classification Protective systems Inspection Employee training An oh sh_t! Soil Classification: Soil Classification Soil Classification (Type A,B,or C) determines construction of protective system: Sloping or benching Shoring Timber shoring Aluminum shoring Protective Systems: - YO! Protective Systems Required unless: Excavation in stable rock Excavation less than 5 ‘ (4’ some states) and examination by Competent Person determines no potential for cave-in Protective Systems: Protective Systems Options Include: Sloping and benching Shoring/sheet piling/ shielding (e.g.trench boxes) Designed by P.E. if deeper than 20’ Simple Sloping: Simple Sloping Type A - 3/4:1 Type B - 1:1 Type C - 1½ :1 Benching: Benching Type A Type B (cohesive soil) Type C NA Shoring: Shoring Based on OSHA Appendices Based on Manufacturer data Designed by a P.E. Timber Shoring Installations: Timber Shoring Installations Appendix C of OSHA regulations Requires soil classification Based on depth and width of trench Consult tables for specs on Cross braces Wales Uprights Aluminum Shoring Installations: Aluminum Shoring Installations Appendix D of OSHA regulations Requires soil classification Based on depth and width of trench Consult tables for specs on Hydraulic cylinders Wales Uprights Shields (i.e. Trench Boxes): Shields (i.e. Trench Boxes) Protective Systems: Protective Systems Installation Securely connected Employees clear of area under shields during installation Installed to prevent movement Must protect employees while entering excavation Protective Systems: Protective Systems Removal Employees clear of area under shields during removal Shoring removed from the bottom up, SLOWLY! Backfill with removal Excavation Inspections: Excavation Inspections Daily Inspections of ALL excavations by Competent Person Start of shift, as needed, following rainstorms or other hazard-increasing event Possible cave-ins Protective system failure Water accumulation Hazardous atmospheres Competent person has authority to remove workers from the excavation Excavation Rescue: Excavation Rescue Excavation Rescue: Excavation Rescue Excavation Rescue: Excavation Rescue Initial Size-up Type of incident? Cave-in, flooding, medical, fire, spill Injuries? Number and type Missing personnel? Chemical (or sewage) exposures? Safety of excavation for rescuers? Excavation Rescue: Excavation Rescue Notify: Field personnel HSO = Emergency Coordinator Fire Department Police Department Emergency Medical Services (EMS)/Hospital Excavation Rescue: Excavation Rescue Stabilize cave-in Control flooding Hazardous Atmospheres? Ventilate SCBA Safety harness and line Basket stretcher Excavation Rescues: DON’T ROLL THE DICE!!! Excavation Rescues The best rescue is the one you never have to make! Practice proper procedures Make sure everything is safe before anybody goes in!