Excavations: Lesson Plan (OSHA 10-Hour Construction Outreach)

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1. Page 1

   IDENTIFICATION

   • TOPIC TITLE: ___Excavations___
   • MINIMUM TIME: __30 minutes___
   • OBJECTIVES
   • Terminal Objective:
   • Given best practices and current OSHA and industry information regarding worksite injuries and/or fatalities, the student will be able to recognize how to protect themselves from hazards associated with excavations.
   • Enabling Objectives:
   • 1. Describe the role of a competent person at an excavation site.
   • 2. Identify hazards associated with excavations.
   • 3. Describe the methods for protecting employees from cave-ins.
   • 4. Apply excavation hazard protection methods.
   • 5. Recognize employer requirements to protect workers from excavation hazards.
   • INSTRUCTOR MATERIALS AND RESOURCES
   • PowerPoint Presentation: Excavations
   • Knowledge Check Answer Key: Excavations
   • STUDENT MATERIALS
   • OSHA Fact Sheet: Trenching and Excavation Safety
   • Knowledge Check: Excavation
2. Page 2

   TEACHING PROCEDURES ---Preparation, Presentation, Application, Evaluation

   • Anticipatory Set (Focus Attention/Gain Interest)
   • Estimated Time: ?? hours
   • Key Points
   • Methods
   • Excavations and trenching activities are some of the most dangerous construction operations. Most accidents tend to happen in trenches between 5-15 feet deep and there’s usually little or no warning before a cave-in occurs.
   • PPT slide #1 – #3
   • According to OSHA, two workers are killed every month in trench collapses. The crushing weight of soil can break bones, impair circulation and breathing, and cause serious internal injuries.
   • Presentation (Instruction)___
   • Key Points
   • Methods
   • I.
   • PPT slide #4 - #5
   • Role of Competent Person
   • A. Required training and knowledge
   • 1. Soil classification
   • 2. Use of protective systems
   • 3. Requirements of OSHA’s standard on excavation and trenching
   • B. Capable of identifying hazards and have authority to eliminate hazards
   • C. Make daily inspections of excavations, areas around them, and protective systems
   • 1. Before work starts and as needed
   • 2. After rainstorms, high winds, or other occurrences that may increase hazards
   • 3. When it can be reasonably anticipated that an employee will be exposed to hazard(s).
   • 4. Remove employees exposed to hazards
3. Page 3

   II. Excavation Hazards

   • A. Cave-ins
   • 1. Greatest risk
   • 2. Open excavation is unnatural and soil wants to flow back together to fill void
   • B. Other potential hazards
   • 1. Falls
   • 2. Falling loads
   • 3. Hazardous environment – considered a confined space; can pose potential risks of oxygen deficiency, toxic fumes, and water accumulation
   • 4. Mobile equipment
   • a. Can contribute to cave-in potential
   • b. Struck-by hazard
   • c. Caught-in/-between hazard
   • 5. Vehicular or traffic hazards
   • a. High-visibility garments needed
   • b. Manual on Uniform Traffic Control Devices (MUTCD)
   • III. Protection from Cave-ins
   • A. Protection from collapse must be provided for all excavations 5 feet or deeper. Workers should never enter an unprotected trench.
   • PPT slide #9 - #17
   • B. Types of protective systems
   • 1. Support/shoring systems
   • 2. Sloping and benching
   • 3. Shield system
   • IV. Protection from Excavation Hazards
   • A. Instability of adjacent structures
   • 1. Structures become unstable when soil next to them is removed
   • 2. Use support system to ensure stability of structure
   • PPT slide #18 - #29
   • B. Underground structures
   • 1. Pipe lines, water or wastewater lines, other utility lines
4. Page 4

   2. Before digging, contact utility or owner

   • 3. Support, protect, or appropriately remove underground installations in open excavations
   • C. Spoil pile
   • 1. Keep at least 2 feet from edge of excavation
   • 2. Place pile so that rainwater runs away from excavation and not into it
   • D. Mobile equipment
   • 1. Danger of falling into excavation
   • 2. Use warning system
   • a. Barricades
   • b. Hand or mechanical signals
   • c. Stop logs
   • 3. Grade soil with angle away from excavation, if possible
   • E. Falling loads
   • 1. Items such as tools, equipment, or construction materials falling into trench
   • 2. Keep items at least 2 feet from edge or use retaining device
   • 3. Do not allow workers to stand or work below loads being handled by lifting or digging equipment
   • F. Hazardous atmospheres
   • 1. Test for hazardous environments before employees enter excavations that are more than 4 feet deep
   • 2. Proper respiratory protection or ventilation must be provided when working in hazardous atmospheres
   • 3. Regularly test all controls used
   • 4. Emergency rescue equipment must be available
   • a. Breathing apparatus
   • b. Safety harness and line
   • c. Basket stretcher
   • G. Water accumulation
   • 1. Risk of cave-in is increased, risk of drowning, increased difficulty of exiting excavation
   • 2. Use water removal equipment
   • 3. Divert surface water away from excavation and provide adequate drainage of adjacent area
   • 4. Competent person should inspect excavations after rains
5. Page 5

   H. Access/Egress

   • 1. Entry/exit can present fall hazards if safe means of access/egress is not in place
   • 2. Survival may depend on quick exit
   • 3. Stairways, ladders, ramps, or other safe means provided in all trenches 4+ feet deep; means of egress within 25 lateral feet of workers
   • I. Hard hats
   • 1. Danger of head injury from impact
   • 2. Hard hats must be worn in excavations 5+ feet deep or when competent person determines hazard exists at lesser depth
   • V.
   • Employer Requirements
   • PPT slide #30 – #32
   • A. Comply with all applicable OSHA standards related to excavations, including:
   • 1. Training requirements
   • 2. Inspection requirements
   • B. Designate a competent person, who has the appropriate experience and training, to:
   • 1. Identify existing and potential hazards and immediately eliminate those hazards.
   • 2. Make daily inspections of excavations, areas around excavations, and protective systems as required by OSHA.
   • 3. Remove exposed employees from hazardous area and not allow employees to return until all necessary precautions have been taken to protect them.
6. Page 6

   Application (How students apply what they learn) __

   • Estimated Time: ?? hours
   • Key Points
   • Methods
   • Show pictures of excavation sites. Have students identify any unsafe actions or conditions and discuss related best practices.
   • PPT slide #33 – #36
   • Evaluation/Summary
   • Key Points
   • Methods
   • Knowledge Check: Excavations
   • PPT slide #37 – #41
   • References
   • OSHA Standard: https://www.osha.gov/pls/oshaweb/owasrch.search_form?p_doc_type=STANDARDS&p_toc_level=1 &p_keyvalue=Construction
   • 1926 Subpart P – Excavations
   • 1926.650 – Scope, application, and definitions applicable to this subpart
   • 1926.651 – Specific Excavation Requirements
   • 1926.652 – Requirements for protective systems
   • 1926 Subpart P App A – Soil Classification
   • 1926 Subpart P App B – Sloping and Benching
   • 1926 Subpart P App C – Timber Shoring for Trenches
   • 1926 Subpart P App D – Aluminum Hydraulic Shoring for Trenches
   • 1926 Subpart P App E – Alternatives to Timber Shoring
   • 1926 Subpart P App F – Selection of Protective Systems
7. Page 7
   • OSHA Publications
   • https://www.osha.gov/pls/publications/publication.arthruz?pType=Industry&pID=213
   • OSHA #2226 Booklet Excavations (2002)
   • OSHA FS-3476 (English) and OSHA FS-3480 (Spanish) Fact Sheet Trenching and Excavation Safety (2011)
   • OSHA #3255 Poster Trenching (2011)
   • OSHA #3243 QuickCard TM Working Safely in Trenches (2011)
   • OSHA References/Resources
   • Construction Safety and Health Outreach Program, Excavations , 1996 https://www.osha.gov/doc/outreachtraining/htmlfiles/excavate.html
   • Safety and Health Topics, Trenching and Excavations , no date https://www.osha.gov/SLTC/trenchingexcavation/index.html
   • OSHA Construction eTool, Trenching and Excavation , 2009 https://www.osha.gov/SLTC/etools/construction/trenching/mainpage.html Prevention Video (v-Tool), Excavations in Construction , no date https://www.osha.gov/dts/vtools/construction/trench_fnl_eng_web.html Prevention Video (v-Tool), Soil Classification , no date https://www.osha.gov/dts/vtools/construction/soil_testing_fnl_eng_web.html