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WeldingWelding Welding joins two pieces of metal by the use of
heat, pressure, or both Brazing or soldering involves a filler metal which
has a lower melting point than the metal pieces to be joined
Metal cutting is done by heating the metal with a flame and directing a stream of pure oxygen along the line to be cut
WeldingWelding
Arc Welding Shielded Metal Arc Welding (SMAW) Metal Inert Gas (MIG) Tungsten Inert Gas (TIG) Plaza Arc Welding (PAW) Submerged Arc Welding (SAW) And Many More…..more than 80 in all
Health HazardsHealth Hazards Gases and Fumes… Welding “Smoke” is a mixture of very fine particles
called fumes and gases Welding “Smoke” contains fumes and gases including… Chromium, nickel, arsenic, asbestos, manganese, silica,
beryllium, cadmium, nitrogen oxides, phosgene, acrolein, flourine compounds, carbon monoxide, cobalt, copper, lead, ozone, selenium, and zinc
Health Hazards…Gases & FumesHealth Hazards…Gases & Fumes
Generally, gases and fumes come from… Base material & filler material Coatings & paints Shielding gases & chemical reactions Process & consumables used Contaminants in the air
Health HazardsHealth Hazards
It is difficult to list all the health effects of welding exposures because the fumes may contain so many different substances that are known to be harmful
The individual components of welding “smoke” can affect just about any part of the body, including the lungs, heart, kidneys, & central nervous system
Health HazardsHealth Hazards
Exposure to welding “smoke” may have… Short-term effects…
Effects happen at or very soon after exposure Long-term effects
Effects may happen after repeated overexposures or an extended time after the exposure
Short-term exposuresShort-term exposures Exposure to zinc, magnesium, copper and
copper oxide can cause metal fume fever Symptoms of metal fume fevere may occur 4 to
12 hours after exposure Symptoms include… Chills, thirst, fever, muscle ache, chest
soreness, coughing, wheezing, fatigue, nausea, and metallic taste in mouth
Short-term exposuresShort-term exposures
Welding “smoke” can irritate the eyes, nose, chest and respiratory tract
Welding “smoke” can cause coughing, wheezing, shortness of breath, bronchitis, pulmonary edema, and pneumontis
Welding “smoke” can cause nausea, loss of appetite, vomiting, cramps, and slow digestion
Short-term exposuresShort-term exposures
Exposure to cadmium can be fatal in a short time Ultraviolet radiation can react with oxygen and
nitrogen to form ozone and nitrogen oxides These gases are deadly at high concentrations
and can also cause irritation of nose and throat and cause serious lung disease
Short-term exposuresShort-term exposures Ultraviolet rays given off by welding can react with
hydrocarbon solvents such as… Trichloroethylene; 1,1,1-trichloroethane; methylene
chloride; & perchloroethylene to form phosgene gas Even a very small amount of phosgene gas may be
deadlyEarly symptoms include dizziness, chills, and cough and usually take 5 – 6 hours to appear
Short-term exposuresShort-term exposures
Arc welding should never be performed within 200 feet of degreasing equipment or solvents
Long-term exposuresLong-term exposures Studies of welders, flame cutters, and burners
have shown that welders have an increased risk of lung cancer…
and…possibly cancer of the larnyx and urinary tract
Remember… welding “smoke” can include cancer causing agents such as…cadmium, nickel, beryllium, chromium, and arsenic
Long-term exposuresLong-term exposures
Welders may experience a variety of chronic respiratory problems, including…
Bronchitis, asthma, pneumonia, emphysema, pneumoconiosis, decreased lung capacity, silicosis, and siderosis
Long-term exposuresLong-term exposures
Other health problems… Heart disease, skin diseases, hearing loss,
chronic gastritis, gastroduodentis, and ulcers of the stomach and small intestine
Reproductive risks
Other Health Risks…Other Health Risks…
Heat exposure…Heat stress, heat stroke
burns, eye injuries from hot slag, metal chips, sparks, and hot electrodes
Other Health Risks…Other Health Risks… Visible light, and ultraviolet and infrared radiation Intense light can cause damage to retina Infrared radiation may damage the cornea and
result in cataracts Invisible UV light can cause “arc eye” or
“welders’ flash”May include sandy or gritty eye, blurred vision, intense pain, tearing, burning and headache
Other Health Risks…Other Health Risks…
Permanent eye damage Skin burns Skin cancer Noise
Can result in stress, increased blood pressure, may contribute to heart disease, tiredness, nervousness, and irratability
Musculoskeletal InjuriesMusculoskeletal Injuries
Back injuries, shoulder pain, tendonitis, reduced muscle strength, carpal tunnel syndrome, white finger, and knee joint diseases
Injuries may be caused by overhead work, vibration and heavy lifting
Electrical HazardsElectrical Hazards
Even though welding generally uses low voltage, there is still a danger of electric shock
Wet work areas, Cramped work spaces Falls, fractures and other accidents can result
from electrical exposure Even small shock can cause brain damage Death can occur from large shocks
Electrical HazardsElectrical Hazards Always use dry gloves Always wear rubber soled shoes Always use insulating layers Protect yourself from surfaces that conduct electricity When working on electrically powered machinery, make
sure the frame is grounded Keep insulation on all welding equipment and components
dry and in good condition Don’t change electrodes with bare hands, wet gloves or
while standing on wet or ungrounded surfaces
Fire and Explosion HazardsFire and Explosion Hazards
Intense heat and sparks can cause fires or explosions if in the vicinity of combustible or flammable materials
Welding and cutting should only be performed in areas free of combustible materials such as trash, wood, paper, textiles, plastics, chemicals, and flammable dusts, liquids and gases
Fire and Explosion HazardsFire and Explosion Hazards Never weld or cut on containers that have held a
flammable or combustible material unless the container is thoroughly cleaned or filled with an inert gas
A fire inspection should be performed prior to leaving a work area and for at least 30 minutes after the operation is completed
Fire extinguishers should be nearby, of proper size, type and number for the hazards involved
Dangerous MachineryDangerous Machinery
All machines in the area with moving parts must be guarded to prevent worker’s contact
Hair, clothing, fingers, etc. When repairing machinery by brazing and
welding, power must be disconnected, locked out, and tagged so the machinery cannot be started up accidentently
Trips and FallsTrips and Falls To prevent trips and falls… keep work areas clear of equipment, machines,
cables, and hoses Always properly maintain and use handrails Always use and maintain safety lines, harnesses
and lanyards Always make sure that scaffolds are properly
assembled and used
Welding Hazards in Confined SpaceWelding Hazards in Confined Space
A work area with limited access, little or no airflow, not intended for continuous occupation
May also have dangerous atmospheres, hazardous configurations, or other hazards
All employees working in or around confined space must be trained
Welding Hazards in Confined SpaceWelding Hazards in Confined Space Never weld or cut in explosive, flammable,
combustible or other dangerous environments Always use all necessary Personal Protective
Equipment (PPE), including, harness and lanyard, respiratory protection, eye protection, etc.
Never work in confined space without a trained attendant
Welding Hazards in Confined SpaceWelding Hazards in Confined Space
Always leave gas cylinders and welding power sources outside the confined space…
Only take hoses or welding leads into confined space
Always removed hoses and/or leads when leaving confined space for breaks, shift or crew changes, etc.
Welding Hazards in Confined SpaceWelding Hazards in Confined Space No worker should work in an area with less than
19.5% or more than 23.5% oxygen content Never ventilate with oxygen Use continuous mechanical ventilation and
proper respiratory protection All pipes, ducts, power lines, etc. that are not
necessary for the work should be disconnected/locked out/tagged out
Compressed Gas HazardsCompressed Gas Hazards
Gas welding and cutting use a fuel gas and oxygen which are stored in high pressure cylinders
Most fuel gases are explosive Pure oxygen will increase the flammability of any
combustible/flammable material
Compressed Gas HazardsCompressed Gas Hazards All cylinders should have caps or regulators Pressure regulators must be designed for gas in use Check all equipment and components prior to use Cylinders must be stored upright and secured Oxygen and fuel gas cylinders must be stored
separately Be aware of flashbacks and backfires?? Close cylinder valves when work is completed or left
unattended during breaks, etc.
Reducing Noise HazardsReducing Noise Hazards Identify hazards and potential hazards prior to
beginning hot work Read the MSDS sheet to identify the hazardous
material used in welding and cutting products, and the fumes that may be generated
Make sure that you know what you are welding before beginning
Cadmium exposure can be fatal in a very short time
Compressed Gas HazardsCompressed Gas Hazards
After a specific hazard(s) has been identified… you can implement appropriate control
method(s) You can use appropriate PPE
Engineering Controls and Work PracticesEngineering Controls and Work Practices Substitute less hazardous materials for
hazardous materials Use cadmium-free silver solders Use asbestos- free electrodes, gloves, and hot
pads Use ventilation to move away or dilute hazards Use work area barriers to protect others working
in the same general area
Engineering Controls and Work PracticesEngineering Controls and Work Practices
Welding booths should be painted with dull finishes so they don’t reflect UV light
Acoustic shields between the worker and noise sources can reduce exposures
Noisy machinery can be totally enclosed
Engineering Controls and Work PracticesEngineering Controls and Work Practices Modify the process or follow safe work practices so that
hazards are eliminated or reduced to the minimum… Don’t weld on painted surfaces; use water table under
plasma arc cutting to reduce noise; Grind instead of air-arcing; use sub arc; position yourself away from fumes; remove nearby flammables/combustibles; properly maintain equipment; proper housekeeping; use lowest possible amperage; hold electrode perpendicular and close to work surface
Never weld or cut within 200 feet of degreasing equipment or solvents
Personal Protective Equipment (PPE)Personal Protective Equipment (PPE) PPE must be used in conjunction with
engineering controls and safe work practicesUse of one does not eliminate the need for the other
Eye protection should be used in all welding operations
Wear face shields or helmets and goggles or safety glasses
Use appropriate filters on eye protection
Filter Lens Shade NumbersFilter Lens Shade Numbers
SMAW – 1/16 - 5/32 = #10 Gas SAW - 1/16 - 5/32 = #11 (nonferrous) Gas SAW – 1/16 – 5/32 = #12 (ferrous) SMAW – 3/16 – ¼ - = #12 5/16 & 3/8 electrodes = #14 Atomic Hydrogen Welding = #10 - #14 Carbon Arc Welding CAW = #14
Filter Lens Shade NumbersFilter Lens Shade Numbers Soldering = #2 Torch Brazing = #3 or #4 Light cutting up to 1 inch = #3 or #4 Medium cutting 1 inch to 6 inches = #4 or #5 Heavy cutting over 6 inches = #4 or #6 Light gas welding up to 1/8” = #4 or #5 Medium gas welding 1/8” to ½ “ = #5 or #6 Heavy Gas Welding over ½ “ = #6 or #8
Protective ClothingProtective Clothing Fire resistant gauntlet gloves Headcap High top hard toed shoes Leather apron Faceshield Flame retardant clothing Safety Glasses Safety helmet
Hearing ProtectorsHearing Protectors
Ear plugs and/or muffs should be worn during noisy operations such as air arcing or grinding
Most welding operations are noisy