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SECTION 2SECTION 2SAFETY and HAZARD SAFETY and HAZARD

PREVENTIONPREVENTION

SECTION 2SECTION 2SAFETY and HAZARD SAFETY and HAZARD

PREVENTIONPREVENTION

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ELECTRICAL SHOCKELECTRICAL SHOCK

Current is the killing factor in electrical shock.

Currents between 100 and 200 mA generally cause the heart to fibrillate.

A 110 volt power circuit will generally cause between 100 and 200 mA current flow through the bodies of most people.

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LOCKOUT – TAGOUT PROCEDURESLOCKOUT – TAGOUT PROCEDURES

Whenever a piece of equipment is being worked on, it should be disconnected from the power source and locked.

The person working on the equipment should carry the only key to prevent accidental activation.

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DO NOT WORK ALONEDO NOT WORK ALONE

If you must test a live circuit, have someone with you ready to turn off the power, call for help, or give cardiopulmonary resuscitation (CPR).

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LEARN FIRST AIDLEARN FIRST AID

Anyone working on electrical equipment should take the time to learn CPR and first aid.

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ELECTRICAL BURNSELECTRICAL BURNS

Do not wear rings or jewelry when working on electrical circuits.

Never use screwdrivers or other conductive tools in an electrical panel when the power is on.

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7PORTABLE ELECTRIC TOOLSPORTABLE ELECTRIC TOOLS

Electric tools constructed with a metal frame should have a safety ground wire in the power cord.

When using an adapter for a two prong receptacle to a three prong cord, be sure the adapter is properly grounded.

More modern hand held tools are constructed in a plastic case for double insulation.

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NON-CONDUCTING LADDERSNON-CONDUCTING LADDERS

Aluminum ladders can be hazardous if they come in contact with power lines.

Fiberglass or wood ladders should be used.

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Pressure Vessels and Piping (1 of 2)Pressure Vessels and Piping (1 of 2)• The pressure in a vessel increases as the

temperature of the vessel increases.– This pressure is a potential danger.

• Refrigerant cylinders should be stored in the upright position.

• Larger cylinders should be moved only when the protective cap is in place.

• Larger cylinders should be secured to carts designed for moving cylinders.

• Always wear gloves and eye protection.

• The pressure in a vessel increases as the temperature of the vessel increases.– This pressure is a potential danger.

• Refrigerant cylinders should be stored in the upright position.

• Larger cylinders should be moved only when the protective cap is in place.

• Larger cylinders should be secured to carts designed for moving cylinders.

• Always wear gloves and eye protection.

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• Take all precautions to prevent tanks from falling over…

- the valve stem may break off, causing the tank to become a projectile

Pressure Vessels and Piping (2 of 2)

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Electrical HazardsElectrical Hazards

• Exercise caution when working on or around electrical circuits.

• Uncontrolled electric current flow can result in electrical shocks or burns.

• Follow lock-out and tag procedures.• Exercise caution when working on live

circuits.• Do not come in contact with energized

conductors.

• Exercise caution when working on or around electrical circuits.

• Uncontrolled electric current flow can result in electrical shocks or burns.

• Follow lock-out and tag procedures.• Exercise caution when working on live

circuits.• Do not come in contact with energized

conductors.

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Electric ShockElectric Shock

• Shock occurs when you become a part of a circuit.

• Severity of a shock is determined by voltage, current, and the path the current takes as it flows through the body.

• Current flow through the heart can be fatal.

• To help prevent shock, wear insulated boots and do not stand in water while working on equipment.

• Shock occurs when you become a part of a circuit.

• Severity of a shock is determined by voltage, current, and the path the current takes as it flows through the body.

• Current flow through the heart can be fatal.

• To help prevent shock, wear insulated boots and do not stand in water while working on equipment.

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Ground Protection (1 of 3)Ground Protection (1 of 3)

• Grounding wires provide protection from electric shock.

• The ground wire provides an alternative path for current to take.

• All tools should be properly grounded.• Do not use tools that have damaged

or missing ground prongs.

• Grounding wires provide protection from electric shock.

• The ground wire provides an alternative path for current to take.

• All tools should be properly grounded.• Do not use tools that have damaged

or missing ground prongs.

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Line

Neutral

• Ungrounded tools have two prongs: One supplies line voltage to the tool and the other is neutral.

• If the tool becomes grounded, current can flow through the tool and through the user to ground causing shock.

Ground Protection (2 of 3)

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LineNeutral

Ground

• Grounded tools have three prongs.

• If the tool becomes grounded, the current will flow to ground through the ground prong, protecting the user.

Ground Protection (3 of 3)

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Other Grounding Tidbits…Other Grounding Tidbits…

• If wall outlets have only two connections and the tool has three prongs, use an adapter.

• Plastic-cased tools are double-insulated and often have only two prongs.

• Battery-operated tools are convenient and safer.

• Ground fault circuit interrupters (GFCI) sense small electrical leaks to ground.

• If wall outlets have only two connections and the tool has three prongs, use an adapter.

• Plastic-cased tools are double-insulated and often have only two prongs.

• Battery-operated tools are convenient and safer.

• Ground fault circuit interrupters (GFCI) sense small electrical leaks to ground.

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Electrical Burns (1 of 2)Electrical Burns (1 of 2)

• Avoid wearing metallic jewelry while working on electric circuits.– Metallic jewelry conducts electricity.

• Never use a screwdriver in an electrical panel when the power is on.

• Burns can result from electric sparks.

• Avoid wearing metallic jewelry while working on electric circuits.– Metallic jewelry conducts electricity.

• Never use a screwdriver in an electrical panel when the power is on.

• Burns can result from electric sparks.

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GROUND

TERMINAL BLOCK

L1 L2

•If the screwdriver slips and makes contact between a hot terminal and ground…

- Electrical sparks can result, causing electrical shock or burn.

Electrical Burns (2 of 2)

19Ladder SafetyLadder Safety

• Nonconducting ladders should be used.• Fiberglass or wooden ladders are preferred.• Ladders should be placed on level surfaces.• Damaged ladders should not be used.• Ladders should be free of oil, grease, and

other slipping hazards.• Ladders should have slip-resistant feet.• Secure the ladder in place whenever

possible.

• Nonconducting ladders should be used.• Fiberglass or wooden ladders are preferred.• Ladders should be placed on level surfaces.• Damaged ladders should not be used.• Ladders should be free of oil, grease, and

other slipping hazards.• Ladders should have slip-resistant feet.• Secure the ladder in place whenever

possible.

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Heat-related Safety IssuesHeat-related Safety Issues

• Torches concentrate large amounts of heat.

• Keep torches away from combustible materials.

• Always keep a fire extinguisher nearby.

• Use a fire shield when soldering near combustibles.

• Hot pipes and motors can cause burns.

• Working outdoors or in hot attics can cause injury.

• Torches concentrate large amounts of heat.

• Keep torches away from combustible materials.

• Always keep a fire extinguisher nearby.

• Use a fire shield when soldering near combustibles.

• Hot pipes and motors can cause burns.

• Working outdoors or in hot attics can cause injury.

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Cold-related Safety IssuesCold-related Safety Issues

• Cold can be just as dangerous as heat.

• Liquid refrigerant can cause frostbite.

• R-22 boils at -41°F at atmospheric pressure.

• Wear warm clothing and waterproof boots when working in cold, wet environments.

• Cold-weather gear should be worn when working in low-temperature freezers.

• Cold can be just as dangerous as heat.

• Liquid refrigerant can cause frostbite.

• R-22 boils at -41°F at atmospheric pressure.

• Wear warm clothing and waterproof boots when working in cold, wet environments.

• Cold-weather gear should be worn when working in low-temperature freezers.

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Mechanical Equipment Safety (1 of 2)Mechanical Equipment Safety (1 of 2)• Rotating machinery can cause injury.• Loose fitting clothing can get caught in

rotating machinery including, fans, belts, and pulleys.

• Never try to stop rotating machinery by hand.

• Jewelry can get caught on machinery.• Always use eye protection when working on

or around rotating machinery.

• Rotating machinery can cause injury.• Loose fitting clothing can get caught in

rotating machinery including, fans, belts, and pulleys.

• Never try to stop rotating machinery by hand.

• Jewelry can get caught on machinery.• Always use eye protection when working on

or around rotating machinery.

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• Never try to stop rotating machinery by hand!

Mechanical Equipment Safety (2 of 2)

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Moving Heavy Objects Moving Heavy Objects

• Use the safest method to move heavy objects.• Get help from others when the object is heavy.• Lift with your legs, not your back.

• Use the safest method to move heavy objects.• Get help from others when the object is heavy.• Lift with your legs, not your back.

• Use hand trucks whenever possible.• Pry bars and dollies can be used.• Use a back brace• Pry bars can also be used

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Refrigerants in the Breathing Space Refrigerants in the Breathing Space

• Refrigerant gases are heavier than air.• These gases displace oxygen.• Avoid breathing refrigerant vapors.• Use proper ventilation.• Special leak detectors and alarms are

required in certain applications.• ASHRAE Standard 34-1992 addresses

refrigerant toxicity and flammability.

• Refrigerant gases are heavier than air.• These gases displace oxygen.• Avoid breathing refrigerant vapors.• Use proper ventilation.• Special leak detectors and alarms are

required in certain applications.• ASHRAE Standard 34-1992 addresses

refrigerant toxicity and flammability.

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Chemical SafetyChemical Safety

• Used to clean condensers, evaporators, and other pieces of equipment

• Used for water treatment• Should be handled according to

manufacturer’s directions– Follow manufacturer’s first aid procedures.

• Can cause irritation to the eyes, throat, and skin.– Be very careful!

• Used to clean condensers, evaporators, and other pieces of equipment

• Used for water treatment• Should be handled according to

manufacturer’s directions– Follow manufacturer’s first aid procedures.

• Can cause irritation to the eyes, throat, and skin.– Be very careful!

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