Construction Hazards and Standards

1. Construction Hazards and Standards MODULE 21

2. Construction vs. General Industry • “Construction, alteration and/or repair, including painting and decorating” is under 29 CFR 1926 – 29 CFR 1910.12 • Repair of existing facilities; replacement of structures and their components • Interpretation: Construction vs. Maintenance

3. 29 CFR 1926 Organization • General • General Interpretations • General Safety and Health Provisions • Occupational Health and Environmental Controls • Personal Protective and Life Saving Equipment • Fire Protection and Prevention • Signs, Signals, and Barricades • Materials Handling, Storage, Use, and Disposal • Tools – Hand and Power

4. 29 CFR 1926 Organization • Welding and Cutting • Electrical • Scaffolds • Fall Protection • Cranes, Derricks, Hoists, Elevators, and Conveyors • Motor Vehicles, Mechanized Equipment, and Marine Operations • Excavations • Concrete and Masonry Construction • Steel Erection

5. 29 CFR 1926 Organization • Underground Construction, Caissons, Cofferdams, and Compressed Air • Demolition • Blasting and the Use of Explosives • Power Transmission and Distribution • Rollover Protective Structures; Overhead Protection • Ladders • Commercial Diving Operations • Toxic and Hazardous Substances

6. Hazards and Standards • What hazards are employees exposed to: • When they set up a drilling site? • When they grade land or excavate? • When they clear a site for use? • Regulations in 29 CFR 1926: • Subpart P – Excavations • Subpart O – Motor Vehicles, Mechanized Equipment, and Marine Operations • If blasting: Subpart O

7. Excavations 29 CFR 1926 Subpart P

8. Excavation Hazards • Excavating is recognized as one of the most hazardous construction operations • Fatality rate for excavations is twice that of construction as a whole • Cave-ins: More likely to result in fatalities than other excavation hazards

9. Hazards of Excavation Work • Cave-ins • Underground utilities • Materials/equipment falling into excavation sites • Asphyxiation • Explosion • Falls • Drowning

10. Soil Mechanics • Unit weight of soils: • Varies with type and moisture content • 1 cubic foot can weigh 100 to >140 lbs • 1 cubic meter can weigh >3000 lbs

11. Types of excavation collapse

12. Heaving or Boiling

13. Definitions • Excavation: any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal. • Trench (Trench excavation): a narrow excavation (in relation to its length) made below the surface of the ground. • Depth>width; width <15 feet • <15 feet between structure and side

14. Definition – Competent Person • Training, experience, and knowledge of: • Soil analysis • Use of protective systems • Requirements of 29 CFR Part 1926 Subpart P • Ability to detect: • Conditions that could result in cave-ins • Failures in protective systems • Hazardous atmospheres • Other hazards including those associated with confined spaces • Authority to take prompt corrective measures to eliminate existing and predictable hazards and to stop work when required

15. 1926.651 Specific Excavation Requirements • Remove or support surface encumbrances (competent person) • Determine location of all underground utilities before opening excavation • OneCall system / 811 • Use safe means to determine exact locations & protect underground utilities

16. 1926.651(c) Access & Egress • Structural ramps for access and egress designed by competent person & constructed according to design • Bar is higher for equipment ramps • Access & egress ramps designed to avoid slipping or tripping

17. 1926.651(c) Access & Egress 4' or greater Every 25' • Stairway, ladder, ramp, other safe egress within 25 feet of employees in trenches >4 feet deep • Ladder requirements apply, including extending 3 feet above top surface

18. 1926.651 Specific Excavation Requirements • In traffic areas, reflective vests required • No workers underneath loads handled by lifting or digging equipment. • Barricades, stop logs or hand signals for mobile equipment operating near excavations

19. 1926.651(g) Hazardous atmospheres • In excavations 4 feet or more where hazardous atmospheres are likely to exist must test atmosphere before entering and retest as necessary • Unsafe below 19.5% oxygen • Stay below 20% of lower flammable limits • Ventilation or PPE must be used as required • Rescue equipment available

20. 1926.651(h) Water Accumulation • Precautions required before working for water in excavations • Competent Person must monitor control measures • If diverting surface water, must take steps to prevent water from entering trench

21. 1926.651(i) Stability of adjacent structures • Structures adjacent to excavations must be supported if stability is affected • No excavation below adjacent footings unless underpinned, or stable rock, or approved by PE • No undermining pavements unless supported

22. 1926.651 Specific Excavation Requirements • Protect employees from falling rock, soil, or materials/equipment falling into excavations. • Keep materials 2 feet from edge • Retaining devices/barricades • Inspections by competent person, daily and as needed during shift • Walkways to cross excavations

23. 1926.652 Requirements for protective systems • Protection of employees in excavations • Design of sloping and benching systems • Design of support systems, shield systems, and other protective systems • Materials and equipment • Installation and removal

24. 1926.652(a) Protection of employees in excavations • Use adequate protective system, except • Excavations entirely in stable rock • <5 feet and competent person sees no potential for cave-in • Capacity for all reasonably expected loads

25. 1926.652(b) and (c) Design of sloping and benching systems • Four choices for sloping: • Slope for type ‘C’, no steeper than 34° • Use sloping choices from Appendices A, B • Tabulated data determined by a PE • Designed by a PE • For support systems, shield systems, other: • Design using Appendices A, C, D • Manufacturer’s tabulated data • Other tabulated data determined by a PE • Designed by a PE

26. 1926.652(d) Materials and equipment • Materials for protective systems free from damage & defects • Used according to manufacturer’s specifications • If damaged, competent person must determine suitability for continued use

27. 1926.652(e) Installation and removal of support • Support system members securely connected together • Installed & removed to assure employee safety • Keep within design capacity • Remove from bottom first, and backfill as you remove

28. 1926.652(f) Sloping and benching systems • No working on sloped or benched faces unless employees below are protected

29. 1926.652(g) Shield systems • Shield systems not subject to loads exceeding their capacity • Installed to restrict lateral movement • Employee protection provided while entering/exiting shields • No employees in trench during installation or removal of shields • May excavate up to 2 feet below shield with proper conditions

30. Trench box Shoring Subtitles & Transitions FOR EXAMPLE… Shielding

31. 1926 Subpart P Appendix A - Soil Classification • A method of categorizing soil and rock deposits in a hierarchy: • Stable Rock • Type A – cohesive soil >1.5 tsf – with exceptions • Type B – cohesive soil >.5-1.5 tsf or granular, disturbed, vibrated, fissured, layered • Type C – cohesive soil <.5 tsf or granular, submerged, layered…

33. Soils - Types & Particle Size • Gravel • larger than 2 millimeters • Sand • Between 0.075 and 2 millimeters • Silt • Between 0.002 and 0.075 millimeters • Clay • Smaller than 0.002 millimeters .

34. Additional soil classification • Layered geological strata: based on weakest layer • May be classified individually if weaker is on top of stronger

36. 1926 Subpart P Appendix A - Soil Classification • Each soil and rock deposit shall be classified by a competent person • Classification made based on at least one visual and one manual analysis

37. Visual tests: Particle size

38. Visual tests • Clumping • Cracks or spalling • Existing utilities/previously disturbed soil • Layers and slope • Water in surface, seeping, water table • Vibration sources

39. Manual tests • Plasticity • Dry strength • Thumb penetration • Pocket penetrometer or shearvane • Drying test

40. Motor Vehicles, Mechanized Equipment, and Marine Operations 29 CFR 1926 Subpart O

41. Organization of Subpart O • 1926.600 - Equipment. • 1926.601 - Motor vehicles. • 1926.602 - Material handling equipment. • 1926.603 - Pile driving equipment. • 1926.604 - Site clearing. • 1926.605 - Marine operations and equipment. • 1926.606 - Definitions applicable to this subpart.

42. 1926.600(a) Equipment - General Requirements • Lights/reflectors on unattended equipment next to highway • Protection for tire changes on split rims • Elevated equipment: protect from falling • Parking brake, plus chocks for inclines • Batteries: by Subpart K • Cab glass: safety glass with no visible distortion • Movement around power lines or transmitters • Stops for railroad cars on spurs

43. 1926.601 – Motor Vehicles • Coverage. • Motor vehicles that operate within an off-highway jobsite, not open to public traffic • Not for material handling equipment covered under 1926.602.

44. 1926.601(b) General requirements • Brake system in operable condition: • Service brake system • Emergency brake system • Parking brake system • 2 headlights & 2 taillights if needed, depending on visibility • Brake lights regardless of visibility

45. 1926.601(b) General requirements • Audible warning device (horn) • Obstructed rear view: must have • Reverse signal alarm audible above surrounding noise level or • Backed up only when observer signals that it is safe • Windshields & powered wipers on cabs • Fix cracked glass • Defogger/defroster where necessary

46. 1926.601(b) General requirements • Haulage vehicles: cab shield and/or canopy adequate to protect the operator from shifting or falling materials • Secure tools and material from movement in compartments with employees • Seats firmly secured and adequate for employees being carried

47. 1926.601(b) General requirements • Seat belts and anchorages meeting 49 CFR Part 571 • Dump bodies supported, locked into position for maintenance or inspection • Latch on hoisting/dumping devices to prevent accidental operation • Trip handle of dump truck tailgate: operator must be clear when dumping

48. 1926.601(b) General requirements • Rubber-tired equipment must have fenders or mud flaps • Vehicles checked at beginning of shift: • All brake systems • Tires • Horn • Steering • Coupling • Seat belt • Controls • Safety devices • Lights/reflectors • Wipers/defrosters • Fire extinguishers

49. 1926.602 – Material Handling Equipment • Application: • Scrapers, loaders, crawler or wheel tractors, bulldozers, off-highway trucks, graders, agricultural and industrial tractors, and similar equipment • Compactors and rubber-tired "skid-steer" equipment: reserved

50. 1926.602(a)(2) Seat belts • Provided and must meet standards • Not necessary for standup operations • Not necessary for equipment without roll-over protective structure (ROPS) or canopy protection • ROPS: See 1926 Subpart W