1. POWER TOOL SAFETY

2. Powder Actuated Fastener
Power Tools
Operated with external power
Determined by their power source (electric, pneumatic, powder actuated, etc.)
Some examples are:
Power Saws
Grinders
Power Drills, etc.
Powder Actuated Fastener
Unlike hand tools, power tools are operated with external power. The types of power tools can be determined by their power source, such as electric, pneumatic, liquid fuel, hydraulic, and powder actuated.
The size and capacity of power tools vary with the scope of the job to be performed.
Power tools pose more hazards than the manual tools since they are energized and possess enormous amounts of energy.
Some examples of power tools are:
Jackhammers
Power saws (e.g. chainsaw, circular saw, table saw, swing cut-off saw)
Grinders
Sanders
Planers
Power drills, etc.
Grinder
Jackhammer

3. Hand Tools Hazards: Misuse of tools or using tools for wrong tasks
Using damaged tools (poor maintenance)
Poor housekeeping and improper storage (tripping hazard)
The injuries with hand tools occur due to misuse or improper maintenance of tools.
For example, if a wooden handle on a tool, such as a hammer or an axe, is loose, splintered, or cracked, the head of the tool may fly off and strike the user or other employees.
Poor housekeeping of the construction site, not properly stored and/or unattended hand tools pose tripping and slipping hazards to workers.
Poor Housekeeping

4. Hand Tools Injury/Illness Prevention:
Inspect and remove unsafe hand tools
Keep workspace as clean as possible and don’t leave tools laying around unattended
When using saw blades and knives, direct the tools away from other workers working in close proximity
When using equipment with long handles (e.g. bullfloat), keep it clear from the path of traffic or construction equipment
The employer is responsible for the safe condition of tools and equipment used by employees. Employers must not issue or permit the use of unsafe hand tools. Employees should be trained in the proper use and handling of tools and equipment.
Workspaces must be kept as clean as possible to prevent accidental slips and trips with or around dangerous hand tools. Workers must not leave their hand tools unattended.
Workers, when using saw blades, knives, or other tools, should direct the tools away from aisle areas and away from other employees working in close proximity. Knives and scissors must be sharp; dull tools can be more hazardous than sharp ones. Cracked saw blades must be removed from service.
When workers use equipment with long handles (e.g. bullfloat), they must keep it clear from the path of traffic or construction equipment.

5. Hand Tools Injury/Illness Prevention:
Stay away from flammable substance while working with hand tools that may produce sparks
Keep wooden handles of tools free of splinters and cracks
Keep impact tools free of mushroomed heads
Wear appropriate personal protective equipment
Iron or steel hand tools that may produce sparks can be an ignition source around flammable substances. Where this hazard exists, spark-resistant tools made of non-ferrous materials should be used where flammable gases, highly volatile liquids, and other explosive substances are stored or used.
Impact tools, such as drill pins, wedges, and chisels, shall be kept free of mushroomed heads.
The wooden handles of tools shall be kept free of splinters or cracks and shall be kept tight in the tool.
Appropriate personal protective equipment, such as safety goggles and gloves, must be worn for protection against hazards that may be encountered while using hand tools.

6. Power Tool Hazards and Injury/Illness Prevention
General Safety Precautions
Machine Guarding
Electric Tools
Power Saws
Portable Abrasive Wheel Tools
Pneumatic Tools

7. General Safety Precautions for Power Tools
Disconnect tools when not in use
Never carry a tool by the cord or hose
Keep cords and hoses away from heat, oil, and sharp edges
Avoid accidental starting
Do not hold fingers on the switch button while carrying a plugged-in tool

8. General Safety Precautions for Power Tools
Secure work with clamps or a vise, freeing both hands to operate the tool
Keep all people not involved with the work at a safe distance
Be sure to keep good footing and maintain good balance when operating power tools
Wear proper apparel for the task

9. Machine Guarding Guard exposed moving parts of power tools
Machine guards must protect the operator and others from:
Point of operation
In-running nip points
Rotating parts
Flying chips and sparks
Guards must be properly affixed to the machine
Never remove safety guards when a tool is still in use

10. Electric Tools Electrical shock and fire hazards due to:
Damage or internal defects
Improper or no grounding
Defective insulation and wiring
Damage to insulation
Due to overworking, overheating.
Employees using electrical tools must be aware of several dangers.
Among the most serious hazards are electrical burns and shocks. Under certain conditions, even a small amount of electric current can result in fibrillation of the heart and death. Also an electric shock can cause the user to fall off a ladder or other elevated work surface and get injured.
Electrical shocks are mostly caused by damage or internal defects, and improper grounding (no grounding). Defective insulation of connecting cables, faults, and defects in conductors, defective enclosures, and damaged receptacles and sockets are other sources of hazards.
The defects in the tools may be due to overworking, overheating, or damage to insulation or grounding.
Defective insulation

11. Electric Tools Hazards: Damaged cords Reversal of polarity in wiring
Using tools in wet areas
Damaged cords have resulted in many construction accidents. If damaged cords are found, they should be immediately replaced because they can lead to electrocution.
Reversal in polarity in wiring (the reversal of hot and neutral wires) can also cause electrocution.
Use of electric tools in wet areas exposes the operator to electrical shock.
Cord, plug and ground prong should be in good condition

12. Electric Tools Injury / Illness Prevention:
Connect tools only to outlets with ground fault circuit interrupters (GFCI)
Inspect tools and extension cords before each use
Use durable and weather proof extension cords
Use cords with three prong plugs
In the construction industry, employees who use electric tools must be protected by ground-fault circuit interrupters (GFCI) or an assured equipment-grounding conductor program.
Electric tools shall be inspected for any damage prior to each use. The handle and body casing of the tools shall be checked for cracks or other damage. If a tool is found defective, it should be removed from service and should be tagged “Out of Service”. The defective tools shall be replaced immediately and shall not be assigned to “temporary” use. The tools shall be repaired by a qualified person. Field repairs shall not be attempted.
Extension cords should be durable and be weather proofed. Cords should be rated for outdoor use, but should still be kept away from water, since moisture can seep into insulation. Cords should be inspected to ensure that the entire length of insulation is intact and the plug pins are not damaged.
To protect the user from shock and burns, electric tools must have a three-wire cord with a ground and be plugged into a grounded receptacle; be double insulated; or be powered by a low voltage isolation transformer. Three-wire cords contain two current carrying conductors and a grounding conductor. Any time an adapter is used to accommodate a two-hole receptacle, the adapter wire must be attached to a known ground. The third prong must never be removed from the plug.
GFCI

13. How Does GFCI Work? Ground-Fault Circuit Interrupter (GFCI)
Fault developed within tool from “hot” conductor to metallic tool case
120-v 60 Hz Electric Supply Service
1 ½ Amperes “going” to tool
Ground-Fault Circuit Interrupter (GFCI)
GFCI
“Hot Conductor”
1 Ampere “returning’ from tool
Grounded neutral
Its about the differential of outgoing and returning
The ground-fault circuit interrupter, or GFCI, is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors.
Equipment grounding conductor
Leakage Current
Leakage Current
Ground

14. Do not use wires with worn out insulation
Electric Tools
Injury / Illness Prevention:
Operate electric tools within the limits of their design
Do not use electrical tools in damp and /or wet areas
Remove all damaged portable electric tools from use
Ensure that electrical cords do not present tripping hazards
Use gloves and appropriate safety footwear when using electric tools
Do not use wires with worn out insulation
When operating electric tools, be sure to consult the users manuals and only operate them within the limits of their design, and for the applications in which they are intended.
Do not use electric tools in damp or wet locations unless they are approved to that purpose. Electric tools should be stored in a dry place when not in use.
Remove all damaged portable electric tools from use and attach a “Do Not Use” tag to them so that other workers are aware that they are damages and are not available for use. Tools that are tagged out should not be used by anyone.

15. Power Saws Hazards: Lack of proper guarding
Sawing objects not adequately supported
Dust inhalation due to lack of personal protective equipment
Operator distraction
Saw not stored
properly after use
Sawing hazards include the following:
Poorly maintained saws may lack fixed guards over the blades, and the blades not being adequately secured.
During use, material being cut may not be adequately supported.
Dust inhalation can cause health problems to the workers.
Operator distraction can cause accidents.
Foreign objects (such as nails) in the material can shatter and fly in pieces upon contact with the blade, and injure the operator.

16. Power Saws Prevention: Proper machine guarding
Use of respiratory protection and safety goggles
Don’t keep saws and blades in motion when not in use
Portable circular saws having a blade greater than 2 inches in diameter must be equipped with guard at all times. An upper guard must cover the entire blade of the saw. A retractable lower guard must cover the teeth of the saw, except where it makes contact with the work material. The lower guard must automatically return to the covering position when the tool is withdrawn from the work material.
Chip Guard on Saw

17. Portable Abrasive Wheel Tools
Hazards:
Flying fragments
Defective or cracked wheels
Wheel breakage during start-up

18. Portable Abrasive Wheel Tools
Injury/Illness Prevention:
Proper machine guarding
Cover the spindle end, nut, and flange projections
Maintain proper alignment with the wheel
Do not exceed the strength of the fastenings
Before mounting the wheel, inspect for damage and perform “ring-testing” (tap with a light instrument)
Ensure wheel fits freely on the spindle
Spindle speed should not exceed the maximum operating speed
Never stand in the plane of rotation as the wheel accelerates to full operating speed
Portable abrasive grinding, cutting, polishing, and wire buffing wheels create special safety problems because they may throw off flying fragments. Abrasive wheel tools must be equipped with guards that: (1) cover the spindle end, nut, and flange projections; (2) maintain proper alignment with the wheel; and (3) do not exceed the strength of the fastenings.
Before an abrasive wheel is mounted, it must be inspected closely for damage and should be sound- or ring-tested to ensure that it is free from cracks or defects. To test, wheels should be tapped gently with a light, non-metallic instrument. If the wheels sound cracked or dead, they must not be used because they could fly apart in operation. A stable and undamaged wheel, when tapped, will give a clear metallic tone or “ring”.
To prevent an abrasive wheel from cracking one must ensure that it fits freely on the spindle. The spindle nut must be tightened enough to hold the wheel in place without distorting the flange. Always follow the manufacturer’s recommendations. Take care to ensure that the spindle speed of the machine will not exceed the minimum operating speed marked on the wheel.
An abrasive wheel may disintegrate or explode during start-up. Allow the tool to come up to operating speed prior to grinding or cutting. The employee should never stand in the plane of rotation of the wheel as it accelerates to full operating speed. Portable grinding tools need to be equipped with safety guards to protect workers not only from the moving wheel surface, but also from flying fragments in case of wheel breakage.
When using a powered grinder:
Always use eye or face protection
Turn off the power when not in use
Never clamp a hand-held grinder in a vise
Never place the grinder face down on work bench (when it’s not in use)

19. Applicable Standards OSHA General Industry OSHA Construction
1910 Subpart P, Hand and Portable Power Tools and Other Hand-Held Equipment
OSHA Construction
1926 Subpart I, Tools – Hands and Power

20. Summary
Hand and power tools range from simple to complex and are of various types
Hand and power tools pose various hazards
Injury prevention techniques include
Use of safe operating practices
Maintaining safe working conditions
Understanding the hazards associated with hand and power tools and their injury prevention techniques are critical to improve worker safety