CHEM 421L Safety Presentation

1. CHEM 421L Safety Presentation

2. Hazard Symbols You Must Know

4. Take Electricity Seriously • Over 30,000 non-fatal shocks occur each year. • Over 600 deaths occur annually due to electrocution. Source: Bureau of Labor Statistics

5. Electrical Accidents • Leading Causes of Electrical Accidents: • Drilling and cutting through cables • Using defective tools, cables and equipment • Failure to maintain clearance distance of 10 feet • Failure to de-energize circuits and follow Lockout/Tagout procedures • Failure to guard live parts from accidental worker contact • Unqualified employees working with electricity • Improper installation/use of temporary electrical systems and equipment • By-passing electrical protective devices • Not using GFCI (ground fault circuit interrupters) devices • Missing ground prongs on extension cords

6. Hazards of Electricity • Shock – Most common and can cause electrocution or muscle contraction leading to secondary injury which includes falls • Fires – Enough heat or sparks can ignitecombustible materials • Explosions – Electrical spark can ignitevapors in the air • Arc Flash - can cause burns ranging from 14,000 °F to 35,000 °F • Arc Blast – In a short circuit event copper can expand 67,000 times. The expansion causes a pressure wave. Air also expands, adding to the pressure wave.

7. Fundamentals of Electricity • Electrical current is the flow of electrons through a conductor. • A conductor is a material that allows electrons (current) to flow through it. • An insulatorresists the flow of electrons. • Resistance opposes electron flow.

8. How Shocks Occur • Current travels in closed circuits through conductors (water, metal). • Shock occurs when the human body becomes a part of the circuit. • Current enters at one point & leaves at another.

9. Severity of the Shock Severity of the Shock depends on: • Amount of current • Determined by voltage and resistance to flow • Path through the body • Duration of flow through the body • Other factors such as general health and individual differences

10. Effects of Current Flow • More than 3 milliamps (ma): painful shock • More than 10 ma: muscle contraction • More than 20 ma: considered severe shock • More than 30 ma: lung paralysis - usually temporary • More than 50 ma: possible ventricular fibrillation(usually fatal) • 100 ma to 4 amps: certain ventricular fibrillation (fatal) • Over 4 amps: heart paralysis; severe burns

11. Electrical Isolation • We can be safe by keeping electricity away from us. We can: • Insulatethe conductors • Example: The insulation on extension cords • Elevatethe conductors • Example: Overhead powerlines • Guard the conductors by enclosing them • Example: Receptacle covers, boxes, & conduit

12. Insulating the Conductors Insulated (but not grounded) • The first way to safeguard workers from electrically energized wires is through insulation. • Rubber and plastic is put on wires to prevent shock, fires, short circuits and for strain relief. • It is always necessary to check the insulation on equipment and cords before plugging them in. • Remember, even the smallest defect will allow leakage! Insulated (also grounded – see third pin)

13. Defective Extension Cords Throw this away and buy a new one! Don’t use it! Photos depict hazardous condition

14. Guarding the Conductors • Another way we safeguard workers from electrically energized wires is by guarding them. • Covers, boxes, and enclosures are often put around conductors to prevent worker contact. • It is always necessary to check that electrical boxes and panels are covered and free from missing “knock-outs.” • Remember, electric equipment operating at 50 volts or more must be guarded! No knock-outs! Photo depicts hazardous condition

15. Guarding the Conductors Don’t use either one of these!! Photos depict hazardous condition

16. Guarding the Conductors Put a cover on this! Yikes! Photos depict hazardous condition

17. Equipment Grounding • We can be safe by providing a separate, low resistance pathway for electricity when it does not follow normal flow (ground prong/pin). • Grounding gives the stray current somewhere to go and keeps your body from becoming part of the circuit. Use non-conducting (wood, plastic) supports when using power tools

18. Defective cord incident with metal support • Worker attempted to climb scaffold with electric drill • Drill was used, even though the cord was damaged with bare wires showing • The bare wire contacted the metal scaffolding • The worker was electrocuted Depicts hazardous condition

19. Can You Rely on Grounding? • Grounding will not workif the electricity can flow through you more easily than the ground. You become the path of least resistance = electrocution • This can happen when: • Your tool doesn’t have a ground pin. • You are working in wet locations. • You are touching a metal object. Pay attention to your surroundings when you use grounded portable tools

20. What Must be Grounded? • All circuits and extension cords • All noncurrent carrying metal parts • Portable & semi-portable tools and equipment unless double insulated A plug with a ground pin (good!)

21. Do not use a cord or tool if the ground pin has been removed Don’t Use This! Don’t Use This! Photos depict hazardous condition • You will become the path of least resistance for current = electrocution

22. Do Not Reverse Polarity or use a cord/tool with reversed polarity Photo depicts hazardous condition The prongs are different sized so you can not turn the plug around. If you do, the electrical fields are always energized. If there is moisture present, the case is likely to be “hot”. Even with double-insulated tools, you still could get a shock. Don’t use this!

23. Circuit Interruption • We can be safer by automatically shutting off the flow of electricity in the event of leakage, overload, or short circuit. • Ground Fault Circuit Interrupters (GFCI) are circuit protection (or “overcurrent”) devices that protect you, the worker. • Circuit breakers & fuses protect equipment, not you, because they take too much current & too much time to trip. GFCI protects you. GFCI outlets have the reset buttons.

24. Temporary Wiring • There must be separate circuits for electric tools and lighting, each labeled as such. • Light circuits do not require a GFCI. • Unless used in a wet location. • Test branch circuits before use • Maintain vertical clearances • Insulate wires from their supports Wrong place for cord Cords must be draped overhead to protect you and your labmates

25. SUBPART Extension Cords and Cables • Must be in good shape without splices • Cannot be secured with staples, nails or bare wire • Must be protected from damage • Must have a ground pin • Should be inspected regularly and pulled from service if defective • Cannot be repaired with electrical or duct tape Must repair with heat-shrink sleeve or bonding/vulcanizing tape to retain original insulation properties Bad idea! Bad idea! Photos depict hazardous condition

26. Yikes! Photo depicts hazardous condition

27. Safe Work Practices • De-energized circuits and equipment must be locked/tagged out. Lock the box for your protection If you are working on a circuit with a fuse, lock the fuse box while you work – or, someone could come and flip the switch back on while you’re working.

28. SUBPART K 53 Safe Work Practices • No metal supports or ladders used during or near electrical work. • No wet hands when plugging or unplugging cords/equipment. • No raising or lowering tools by the cord. • Unless equipment is designed for it, do not use electrical tools or equipment in damp and wet locations. Photo depicts hazardous condition Getting through this person to the ladder is now the path of least resistance for the current = electrocution Bad idea!

29. SUBPART K 55 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 electrical panels by Competent Person • Employee training • Ensure competent person on site • Use proper approved electrical equipment • Have qualified person install electrical devices 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 power lines • All hazards are made worse in wet conditions • Using damaged extension cords • Unqualified workers doing electrical work

30. Injury Procedure • First Aid kits are available in the lab with band aids and other items for treating small cuts and burns. • Campus public safety can be reached at 3-5609 for non-emergencies. • If it is a serious injury, call 911 for emergencies. • The LiveSafe app can also be used to report emergencies and non-emergencies.

31. Report any concerns • If you have any safety concerns about the lab you are working in or the people working around you, you can contact: • Your lab instructor • Dr. Marcello Forconi – Head of the departmental safety committee • Dr. Pamela Riggs-Gelasco – Department Chair for Chemistry and Biochemistry • Dr. Jim Deavor, Associate Dean of the School of Science and Mathematics.