© 2012 delmar, cengage learning chapter 2 safety in welding

© 2012 Delmar, Cengage Learning© 2012 Delmar, Cengage Learning

Chapter 2

Safety in Welding


Objectives

• Describe the three classifications of burns and the emergency steps that should be taken to treat each of them

• Describe the dangers all three types of light pose to welding and how to protect yourself and others from these dangers

• Explain how to avoid eye and ear injuries• Use a chart to select the correct eye and face

protective devices for working and welding in a shop


Objectives (cont'd.)

• List the safety points that should be covered in a training program for respiratory protection

• Describe the various types of respiratory protection equipment that are available

• Tell how to avoid dangerous fumes and gases by providing ventilation to the welding area

• Explain the purpose of material safety data sheets (MSDSs) and where they can be found

• Discuss the benefits of recycling waste material



• Describe what type of general work clothing should be worn in a welding shop

• Describe special protective clothing worn by welders to protect the hands, arms, body, waist, legs, and feet

• Describe the proper way to handle, secure, and store cylinders

• Discuss how to protect against the danger of fire when welding



• Explain why planned maintenance of tools and equipment is important

• Describe the most commonly used hand and power tools used by a welder

• Explain good electrical safety practices and list rules for extension cords and portable power tools

• Discuss the types of metal cutting machines• Describe proper ways to safely lift heavy welded

assemblies• List the rules for ladder safety


Introduction

• No substitute for caution and common sense– Each person must take personal responsibility

• Their own safety and safety of others on the job

• Welding is a very large and diverse industry– This chapter concentrates on light welding

fabrication• A number of potential safety hazards

• Learning to work safely – As important as learning to be a skilled welding

fabrication worker


Burn Classification

• Burns – One of the most common and painful injuries

– Caused by ultraviolet light rays or contact with hot welding torches

– Chance of infection is high• All burns must receive proper medical treatment

– Divided into three classifications• First-degree, second-degree, and third-degree


First-Degree Burns

• Characteristics – Surface of the skin is reddish, tender, and painful

– No broken skin

• Treatment– Put burned area under cold water or apply a cold

compress

– Cover the area with sterile bandages

– Never apply butter or grease


FIGURE 2-1 First-degree burn—only the skin surface (epidermis) is affected. © Cengage Learning 2012


Second-Degree Burns

• Characteristics – Surface of the skin is severely damaged

– Blisters and possible breaks in the skin

• Treatment– Put the area under cold water or use cold water

compresses

– Pat area with a dry lint-free towel and cover with a sterile bandage

– Seek medical attention


FIGURE 2-2 Second-degree burn—the epidermal layer is damaged, forming blisters or shallow breaks.© Cengage Learning 2012


Third-Degree Burns

• Characteristics– Surface of skin appears white or charred

• Treatment– Never remove any clothing

– Never use ice water or ice, ointments, sprays, etc.

– If victim is on fire: smother fire with a blanket, rug, or jacket

– Cover with a thick, nonfluffy, sterile dressing

– Call for an ambulance


FIGURE 2-3 Third-degree burn—the epidermis, dermis, and the subcutaneous layers of tissue are destroyed.© Cengage Learning 2012


Burns Caused by Light

• Some types of light can cause burns– Ultraviolet

– Infrared

– Visible

• Arc welding produces all three types of light– Gas welding produces visible and infrared light only

• Light from the welding process – Can be reflected from walls, ceilings, floors, etc.


Ultraviolet Light

• Ultraviolet light waves – Most dangerous

– Causes first- and second-degree burns to eyes or exposed skin

– Closer welder is to the arc and higher the current: quicker a burn may occur

– Welder's eyes can receive a flash burn in seconds


Infrared Light

• Light wave is felt as heat– A person will immediately feel this type of light

– Burns can be easily avoided

– Protective action should be taken to cover yourself


Visible Light

• Light that we see– Produced in varying quantities and colors

– May cause temporary night blindness

– Too little visible light may cause eye strain

– Visible light is not hazardous


Face, Eye, and Ear Protection

• Eye protection – Must be worn in the shop at all times

• Safety glasses with side shields• Goggles• Full face shield• Flash glasses

• Welding light damage – Often occurs without warning


Welding Helmets

• Even with quality welding helmets, the welder must check for potential problems– Undetectable leaks of ultraviolet light can cause a

welder's eyes to itch or feel sore• Ensure lens gasket is installed correctly• Tape can be used as a temporary repair


Safety Glasses

• Safety glasses with side shields– Adequate for general use

– Not suitable for heavy grinding, chipping, or overhead work

– Must be worn under an arc welding helmet at all times


Ear Protection

• Welding environment can be very noisy– Hot sparks can drop into an open ear and cause

severe burns

– Several forms of protection• Earmuffs cover the outer ear completely• Earplugs fit into the ear canal


Respiratory Protection

• Welding and cutting produce harmful by-products– Respirators protect against welding by-products

• Welders are responsible for following the shop's written respiratory protection policy

• Training should include:– Proper respirator use

– Maintenance schedules and respirator selection

– Procedures for testing the proper fitting and use

– Regular program evaluation


Equipment

• Respiratory protection equipment– Air-purifying respirators

– Atmosphere-supplying respirators

– Demand respirators

– Positive pressure respirators

– Powered air-purifying respirators

– Self-contained breathing apparatuses

– Supplied-air respirators


Fume Sources

• Materials can cause respiratory problems– Paints, coating, or plating on metals

• Before welding or cutting any painted metal: surface must be cleaned

• Marine industry – Still uses lead-based paints

• Exposure to cadmium fumes – Can cause lung and kidney damage

• Best way to avoid problems – Adequate ventilation


Vapor Sources

• Potentially dangerous gases – Also can be present in a welding shop

• Proper ventilation or respirators are necessary when welding in confined spaces

• Ozone gas– Produced by ultraviolet radiation

– Irritates mucous membranes

• Collection of fumes and gases can go unnoticed– Concentrated fumes can cause a fire or explosion


Ventilation

• Welding area should be well ventilated– Natural ventilation is best

– Forced ventilation may be required

– Large enough areas may not require forced ventilation


FIGURE 2-15 A room with a ceiling 16 ft (4.9 m) high may not require forced ventilation for one welder.© Cengage Learning 2012


Forced Ventilation

• Small shops or shops with many welders require forced ventilation– Can be general or localized

– Fixed or flexible exhaust pickups

– Required when welding on metals that give off dangerous fumes


Material Safety Data Sheets (MSDSs)

• Provide details of possible hazards– Must be provided to anyone using the product or

working in the area where products are in use

– Often posted on a bulletin board or put in a convenient place where products are used

– If injured while using a product: take material's MSDS when you seek treatment


General Work Clothing

• Guidelines– Shirts must be long-sleeved

– Pants must be long enough to cover the tops of the boots and must be without cuffs

– Boots must have high tops

– Caps should be thick

– Clothing must be free of frayed edges or holes

• Some clothes have pockets– Not safe to carry a butane lighter or matches while

welding


Special Protective Clothing

• Extra protection is needed for each person who is in direct contact with hot materials– Hand protection

– Body protection

– Waist and lap protection

– Arm protection

– Leg and foot protection


Handling and Storing Cylinders

• Considerations– Store oxygen and fuel gas cylinders separately

– Store inert gas cylinders separately or with oxygen cylinders

– Secure gas cylinders

– Cylinder storage areas must be located away from halls, stairwells, and exits

– Cylinders with a valve protection cap must have the cap in place


General Precautions

• Any cylinders with a defect must be identified– Leak cannot be stopped

• Move cylinder to a vacant lot• Slowly release pressure• Post a warning sign

• Acetylene cylinders – Must be upright for four hours before use

• Otherwise may draw acetone from the cylinder


FIGURE 2-25 Move a leaking fuel gas cylinder out of the building or any work area. The pressure should be slowly released after a warning is posted of the danger.© Cengage Learning 2012


Fire Protection

• Fire is a constant danger– Highly combustible materials should by 35 feet

away from any welding

– Fire watch can be provided by any person who knows how to sound an alarm

– Fire extinguisher must be the type required to put out a fire for the type of combustible material


Fire Extinguishers

• Four types– Type A: combustible solids

– Type B: combustible liquids

– Type C: electrical fires

– Type D: combustible metals

• Location – Appropriate type should be located near types of

combustible materials it is used for


Fire Extinguishers (cont’d.)

• Use– Extinguishers cool the fire and remove oxygen

– Use foam, carbon dioxide, a pump tank, or dry chemicals

• CO2 extinguisher: direct discharge as close to the fire as possible

• Dry chemical extinguisher: direct toward the base of the flames


Equipment Maintenance

• Planned maintenance (PM) – Detects problems

• Hoses must be used for the gas or liquids for which they were designed– Green hoses are used only for oxygen

– Red hoses are used only for fuel gases

• Never use oil grease, or other pipe-fitting compounds on joints– Any leaking or bad joints must be repaired


Work Area

• Considerations– Work area: should be picked up and swept clean

– Arc welding areas: painted with a flat dark color

– Portable screens: used if welding outside the welding booth

– Piece of hot material is left unattended: write hot on it before leaving


Hand Tools

• Used for assembly and disassembly of parts– Adjustable wrench is the most popular

– Fewer points a box end wrench or socket has: the stronger it is

– Mushroomed heads of chisels, punches, and the faces of hammers should be ground off

– Always use the correct tool for the job


Hand Tool Safety

• Considerations– Hand tools should be treated properly and not

abused

– Keep hand tools clean

– Make sure that hand tools are sharp

– Protect cutting edges when carrying

– Keep hammer handles secure and safe

– When swinging a hammer, be absolutely certain that no one is within range


Electrical Safety

• Injuries and death can be caused by electrical shock– Resistance is lowered in the presence of water or

moisture

– Electrically powered machines must be grounded

– Electrical connections must be tight

– Do not allow metal parts of electrodes or electrode holders to touch skin or wet coverings on bodies

– Welding circuits must be turned off when the work station is left unattended


Electrical Safety Systems

• Two safe systems for electrical power tools– External grounding

• A wire runs from the housing to a third prong• Third prong plug fits into grounded outlet

– Double-insulation• Extra layer of insulation • Eliminates need for three-pronged grounded outlet


Voltage Warnings

• Voltage – Same as specified on the tool

• Voltage greater than the tool – Can lead to injury and tool damage

• Voltage lower than the tool – Can damage the motor

• Amperes (Amps) – Measures electrical current


Extension Cords

• Use only three-wire, grounded extension cords– Safety tips

• Connect cord of tool into extension cord first• Unplug extension cord from receptacle first• Extension cords should be long enough• Cord should not come in contact with sharp objects

and must be positioned appropriately • Check for loose or exposed wires and unusual

heating• Use a knot to prevent accidental separation • Clean before storing


Safety Rules for Portable Electric Tools

• Safety precautions– Know the tool and ground when needed

– Do not expose to water

– Keep the area well lighted

– Do not use near propane or flammable vapors

– Do not force a cutting tool to cut faster

– Use the right tool for the job

– Wear eye and face protection

– Secure your work with clamps

– Maintain power tools


Safety Rules for Portable Electric Tools (cont’d.)

– Disconnect from power source when not in use

– Check to see keys or wrenches are removed

– Avoid accidental starting

– Be sure accessories and bits are attached securely

– Do not use tools with cracked or damaged housings

– Give your full and undivided attention

– Never use a power tool with its safeties or guards removed or inoperable


Grinders

• Grinding using a pedestal or portable grinder is required to do many welding jobs– Before a grinding stone is put on a machine, it

should be tested for cracks

– Each grinding stone is made for grinding specific types of metal

– Stone should not be used when worn down

– Gloves should never be worn when grinding


Drills

• Considerations– Secure workpiece before drilling

– Center-punch workpiece before drilling

– Hold drill perpendicular to the face of the work• Except when drilling a hole at an angle

– Use just steady, even pressure

– Drill becomes jammed in the hole• Release trigger immediately• Remove drill bit• Determine cause


Metal Cutting Machines

• Many types– Shears and punches

• Used in fabrication of metal for welding

– Cut-off machines • Use abrasive wheels or special saw blades

– Band saws • Vertical or horizontal• Some can be used in either position


Material Handling

• Improper work habits – Can cause serious personal injury and damage to

equipment and materials

• Lifting– Weight of the object should be evenly distributed

between both hands

• Hoists or cranes – Capacity should be checked before lifting a heavy

load


Ladder Safety

• Improper use of ladders is often a factor in falls– All ladder use poses potential hazards

– Keep the area around the ladder clear

• Step ladders and straight ladders– Used extensively in welding shops


Ladder Safety (cont’d.)

• Ladders can become damaged over time– Look for loose or damaged parts

– Check that all hardware is tight

– Check wooden ladders for cracks

– Never use a defective ladder

– Ladder cannot be repaired: replace it

– Read the entire ladder manufacturer's list of safety rules for ladder use


Summary

• Safety is of the utmost importance– Safety officer ensures welders comply with safety

rules

– Wear proper clothing, shoes, and protection

– Have established procedures in case of accidents

– Check equipment periodically

– Further information is available in Safety for Welders, by Larry E. Jeffus

© 2012 delmar, cengage learning chapter 2 safety in welding

Documents

welding slide

cengage learning objectives

cengage learning chapter

cengage learning introduction

cengage learning figure

welding area

ladder safety slide

shop slide