6 welding safety

Welding Safety

Welding

• 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

Welding

• 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 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 & 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 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 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 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


• 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


• 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


• 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

deadly

– Early symptoms include dizziness, chills, and cough

and usually take 5 – 6 hours to appear


• ARC welding should never be performed within 200 feet of degreasing equipment or solvents

Long-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 exposures

• Welders may experience a variety of chronic respiratory problems, including…

• Bronchitis, asthma, pneumonia, emphysema, pneumoconiosis, decreased lung capacity, silicosis, and siderosis

Long-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…

• Heat exposure…– Heat stress, heat stroke

• burns, eye injuries from hot slag, metal chips, sparks, and hot electrodes


• 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


• 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 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 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 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 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 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 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 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 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


• 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


• 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.


• 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 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


• 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 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


• After a specific hazard(s) has been

identified…

• you can implement appropriate control

method(s)

• You can use appropriate PPE

Engineering 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


• 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


• 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)

• PPE must be used in conjunction with engineering controls and safe work practices– Use 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 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 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 Clothing

• Fire resistant gauntlet gloves• Headcap• High top hard toed shoes• Leather apron• Faceshield• Flame retardant clothing• Safety Glasses• Safety helmet

Hearing Protectors

• Ear plugs and/or muffs should be worn during noisy operations such as air arcing or grinding

• Most welding operations are noisy

Respirators

• Must be specific to the hazard

• Must be fitted, cleaned, stored and maintained in accordance to regulation and manufacturers specs

• NIOSH recommends respirators whenever a carcinogen is present

6 welding safety

Health & Medicine

welding arc welding

welding welding joins

gases welding smoke

fumes welding smoke

welding equipme

welding safety

pneumontis welding smoke

shortterm exposures