Subpart K through O and Related Safety Practices

1. Subpart K through O and Related Safety Practices CHAPTER NINE

2. Subpart K : Electrical Requirements

3. Electrical Injuries There are four main types of electrical injuries: • Direct: • Electrocution or death due to electrical shock • Electrical shock • Burns • Indirect: • Falls

4. Electrical Shock An electrical shock is received when electrical current passes through the body. You will get an electrical shock if a part of your body completes an electrical circuit by… • Touching a live wire and an electrical ground, or • Touching a live wire and another wire at a different voltage. Shock Severity: • Severity of the shock depends on: • Path of current through the body • Amount of current flowing through the body (amps) • Duration of the shocking current through the body, • LOW VOLTAGE DOES NOT MEAN LOW HAZARD

5. Burns Most common shock-related injury Occurs when you touch electrical wiring or equipment that is improperly used or maintained Typically occurs on hands Very serious injury that needs immediate attention

6. Falls Electric shock can also cause indirect injuries Workers in elevated locations who experience a shock may fall, resulting in serious injury or death

7. Electrical Hazards and How to Control Them Electrical accidents are caused by a combination of three factors: • Unsafe equipment and/or installation, • Workplaces made unsafe by the environment, and • Unsafe work practices.

8. Hazard – Exposed Electrical Parts Cover removed from wiring or breaker box

9. Control – Isolate Electrical Parts Guard live parts of electric equipment operating at 50 volts or more against accidental contact • Use guards or barriers • Replace covers

10. Control – Isolate Electrical Parts - Cabinets, Boxes & Fittings Conductors going into them must be protected, and unused openings must be closed

11. Control – Close Openings Junction boxes, pull boxes and fittings must have approved covers Unused openings in cabinets, boxes and fittings must be closed (no missing knockouts)

12. Hazard - Inadequate Wiring Wire Gauge WIRE Wire gauge measures wires ranging in size from number 36 to 0 American wire gauge (AWG) • Hazard - wire too small for the current • Example - portable tool with an extension cord that has a wire too small for the tool • The tool will draw more current than the cord can handle, causing overheating and a possible fire without tripping the circuit breaker • The circuit breaker could be the right size for the circuit but not for the smaller-wire extension cord

13. Control – Use the Correct Wire Must be 3-wire type and designed for hard or extra-hard use Wire used depends on operation, building materials, electrical load, and environmental factors Use fixed cords rather than flexible cords Use the correct extension cord

14. Hazard – Defective Cords & Wires Plastic or rubber covering is missing Damaged extension cords & tools

15. Hazard – Damaged Cords • Cords can be damaged by: • Aging • Door or window edges • Staples or fastenings • Abrasion from adjacent materials • Activity in the area • Improper use can cause shocks, burns or fire

16. Control – Cords & Wires Insulate live wires Check before use Use only cords that are 3-wire type Use only cords marked for hard or extra-hard usage Use only cords, connection devices, and fittings equipped with strain relief Remove cords by pulling on the plugs, not the cords Cords not marked for hard or extra-hard use, or which have been modified, must be taken out of service immediately

17. Hazard – Improper Grounding Tools plugged into improperly grounded circuits may become energized Broken wire or plug on extension cord Some of the most frequently violated OSHA standards

18. Control – Ground Tools & Equipment Ground power supply systems, electrical circuits, and electrical equipment Frequently inspect electrical systems to insure path to ground is continuous Inspect electrical equipment before use Don’t remove ground prongs from tools or extension cords Ground exposed metal parts of equipment

19. Control – Use GFCI (ground-fault circuit interrupter) Protects you from shock Detects difference in current between the black and white wires If ground fault detected, GFCI shuts off electricity in 1/40th of a second Use GFCI’s on all 120-volt, single-phase, 15- and 20-ampere receptacles, or have an assured equipment grounding conductor program.

20. Control - Assured Equipment Grounding Conductor Program Program must cover: • All cord sets • Receptacles not part of a building or structure • Equipment connected by plug and cord Program requirements include: • Specific procedures adopted by the employer • Competent person to implement the program • Visual inspection for damage of equipment connected by cord and plug

21. Hazard – Overloaded Circuits Hazards may result from: • Too many devices plugged into a circuit, causing heated wires and possibly a fire • Damaged tools overheating • Lack of overcurrent protection • Wire insulation melting, which may cause arcing and a fire in the area where the overload exists, even inside a wall

22. Control - Electrical Protective Devices • Automatically opens circuit if excess current from overload or ground-fault is detected – shutting off electricity • Includes GFCI’s, fuses, and circuit breakers • Fuses and circuit breakers are overcurrent devices. When too much current: • Fuses melt • Circuit breakers trip open

23. Safety-Related Work Practices To protect workers from electrical shock: • Use barriers and guards to prevent passage through areas of exposed energized equipment • Pre-plan work, post hazard warnings and use protective measures • Keep working spaces and walkways clear of cords • Use special insulated tools when working on fuses with energized terminals • Don’t use worn or frayed cords and cables • Don’t fasten extension cords with staples, hang from nails, or suspend by wire.

24. Preventing Electrical Hazards - Planning Plan your work with others Plan to avoid falls Plan to lock-out and tag-out equipment Remove jewellery Avoid wet conditions and overhead power lines

25. Preventing Electrical Hazards - PPE • Proper foot protection (not tennis shoes) • Rubber insulating gloves, hoods, sleeves, matting, and blankets • Hard hat (insulated - nonconductive)

26. Preventing Electrical Hazards – Proper Wiring and Connectors • Use and test GFCI’s • Check switches and insulation • Use three prong plugs • Use extension cords only when necessary & assure in proper condition and right type for job • Use correct connectors

27. Training Train employees working with electrical equipment in safe work practices, including : Deenergize electric equipment before inspecting or repairing Using cords, cables, and electric tools that are in good condition Lockout / Tagout recognition and procedures Use appropriate protective equipment

28. Summary – Hazards & Protections • Protective Measures • Proper grounding • Use GFCI’s • Use fuses and circuit breakers • Guard live parts • Lockout/Tagout • Proper use of flexible cords • Close electric panels • Training Hazards • Inadequate wiring • Exposed electrical parts • Wires with bad insulation • Ungrounded electrical systems and tools • Overloaded circuits • Damaged power tools and equipment • Using the wrong PPE and tools • Overhead powerlines • All hazards are made worse in wet conditions

29. Subpart L : Scaffolding

30. 1926.450 Scope, application and definitions

31. What Is A Scaffold? An elevated, temporary work platform Three basic types: • Supported scaffolds -- platforms supported by rigid, load bearing members, such as poles, legs, frames, & outriggers • Suspended scaffolds -- platforms suspended by ropes or other non-rigid, overhead support • Aerial Lifts -- such as “cherry pickers” or “boom trucks”

32. Hazards Falls from elevation – caused by slipping, unsafe access, and the lack of fall protection Struck by falling tools / debris Electrocution – from overhead power lines Scaffold collapse - caused by instability or overloading Bad planking giving way

33. Definitions

34. 1926.451 General requirements Capacity Platform construction Supported scaffolds Suspension scaffolds Scaffold access Scaffold use Fall protection Falling object protection

35. Scaffold capacity and platform construction This is not a properly constructed scaffold Platforms must: • be fully planked or decked with no more than 1 inch gaps • be able to support its weight & 4 times maximum load • be at least 18 inches wide

36. Planks not properly overlapped • No large gaps in front edge of platforms • Each abutted end of plank must rest on a separate support surface • Overlap platforms at least 12 inches over supports, unless restrained to prevent movement

37. No paint on wood platforms • Use scaffold grade wood • Fully planked between front upright and guardrail support • Component pieces used must match and be of the same type • Erect on stable and level ground • Lock wheels and braces

38. Supported Scaffolds This support is not adequate! Platforms supported by legs, outrigger beams, brackets, poles, uprights, posts, & frames Restrain from tipping by guys, ties, or braces Scaffold poles, legs, posts, frames, and uprights must be on base plates and mud sills or other firm foundation

39. Scaffold Support Examples Base plate Mud sills Good support Inadequate support – in danger of collapse?

40. Suspension Scaffolds Platforms suspended by ropes or wires. Rope must be capable of supporting 6 times the load Train employees to recognize hazards Secure/tie to prevent swaying Mandatory requirements : Support atleast four times the operating load of the scaffold. Support 1.5 times the scaffold load when operating at the stall load of the hoist. The greater of these two requirements is the one that applies.

41. Scaffold Access Do not access by crossbraces Provide access when scaffold platforms are more than 2 feet above or below a point of access No access by crossbraces Permitted types of access: • Ladders, such as portable, hook-on, attachable, stairway type, and built-ins • Stair towers • Ramps and walkways May use building stairs and come out window. Can access from another scaffold, structure or hoist

42. Requirements for safe scaffold use A covered scaffold has special wind load considerations Don’t work on snow or ice covered platforms or during storms or high winds Use tag lines on swinging loads Protect suspension ropes from heat & acid. Don’t use shore or lean - to scaffolds.

43. Moving scaffolds Employees can’t be on a moving scaffold unless: • Surface is level • Height to base ratio is 2 to 1 • Outriggers are installed on both sides of scaffolds Competent person must be on site to supervise

44. Scaffold inspection Deformed bearer Competent person inspects scaffolds for visible defects before each shift and after any alterations Defective parts must be immediately repaired

45. Scaffold Erection Scaffolds can only be erected, moved, dismantled or altered under the supervision of a competent person Competent person selects & directs these workers and determines the feasibility of fall protection

46. Fall protection If a worker on a scaffold can fall more than 10 feet, protect them by: Guardrails, and/or Personal Fall Arrest Systems (PFAS)

47. A guardrail or personal fall arrest system is required on all sides except the side where the work is being done. • You must be trained how to properly use PFAS • PFAS include anchorage, lifeline and body harness.

48. Falling Object Protection • Wear hardhats • Barricade area below scaffold to forbid entry into that area • Use panels or screens if material is stacked higher than the toeboard • Build a canopy or erect a net below the scaffold that will contain or deflect falling objects

49. 1926.452 Requirements for specific types of Scaffolds

50. 1926.453 Aerial lifts Aerial lifts are vehicle mounted mechanisms used to elevate workers to locations above the ground that would otherwise be inaccessible to them. Types : Extensible boom platforms Aerial ladders Articulating boom platforms Vertical towers