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Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls
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Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls
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What Are Welding Fumes ? vWelding Causes Solid Metal To Vaporize FUME vAs Vaporized Metal Cools, It Condenses To Reform As Solid Particles - FUME vFumes Are Very Small Particles - - Usually Much Smaller Than Dust l Dust Usually Larger Than 1 Micron l Fumes Can Be As Small As 1/1,000 Micron vUnless Captured And Removed, Fumes Remain Suspended In Air Indefinitely
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How Big Is A Micron ?
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Head of Pin 1/32 Inch
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How Big Is A Micron ? Head of Pin 20 Microns 1/32 Inch
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Size Comparison of Small Particles m Washed Foundry Sand 200 to 2,000 Plant Spores10.0 to 40 Red Blood Cells 7 Cement Dust 1.0 to 10 Bacteria1/10 to 10 Tobacco Smoke 1/100 to 1/2 Metal Fumes 1/1,000 to 1.0
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Composition of Welding Fumes vComposition Varies Depending On: l Material Being Welded l Welding Process, Rod, Electrode Type l Obtain MSDS From Manufacturer vTypical Welding Fume Constituents: l Aluminum, Cadmium, Chromium, Iron, Moly l Cobalt, Copper, Zinc, Manganese, Tin, Lead l Nickel, Arsenic, Mercury, Vanadium, l Beryllium, Magnesium, Titanium, vMay Be Metal or Oxide
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Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls
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Exposure Primarily By Inhalation
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Exposure Primarily By Inhalation Fumes Are 100% Respirable
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Exposure Primarily By Inhalation Fumes Are 100% Respirable What Does “Respirable” Mean ?
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Welding Fume Toxicity vAcute Toxicity l Exposure To High Concentration Over Relatively Short Time l Symptoms Appear Relatively Quickly After Exposure vChronic Toxicity l Exposure To Lower Concentration Over Long Time (Months, Years) l Symptoms Appear Long After Initial Exposure
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Welding Fume Toxicity Kidney Nervous Liver GI Lung Aluminum X X Beryllium X Cadmium X X X X Chromium X X X X Cobalt X X X Copper X X Iron X X X X Lead X X X Manganese X X Nickel X X Zinc X X
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Welding Fume Toxicity vExposure Usually Involves More Than One Metal Additive l Toxic Effects May Be Additive vExamples l Blood - Manganese and Lead l CNS - Manganese and Lead l Kidney - Lead and Cadmium l Respiratory System - Magnesium, Manganese, Copper, and Zinc
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Welding Fume Toxicity vMetal Fume Fever l Symptoms Are Fever, Chills, Shaking l Symptoms Appear 4-12 Hrs After Exp. l Recovery Usually Within 1 Day l Usually Associated With Brief High Inhalation Exposure To Zinc, But Magnesium & Copper Also May Cause l Daily Exposure May Confer Immunity l Symptoms May Return If Exposure Interrupted (3-Day Weekend)
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Welding Fume Toxicity vWelding Fumes Can Cause Cancer l Arsenic (Lung, Lymphatic) l Beryllium (Lung) l Cadmium (Prostatic and Lung) l Chromium (Lung) l Nickel (Lung) vWelders May Also Be Exposed To: l Silica, Asbestos, Ozone l Thermal Decomposition of Paint, Flux, Electrode Coatings (CO, CO 2, NO, NO 2, HCN, COCl 2, Fluoride Gases, Smoke, Etc.)
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Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls
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MSHA Regulations § 56/57.5001 § 56/57.5001 Establishes Exposure Limits For Airborne Contaminants l TWA 8 And Ceiling Limits Listed In 1973 ACGIH Booklet of Threshold Limit Values (TLV’s) u TWA 8 Time Weighted Average For 8 Hrs u Ceiling Limits Cannot Be Exceeded For Any Length Of Time l ACGIH 1973 TLV Booklet References 1968 “PA Rules” For Short Term Limits
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Exposure Limits For Common Welding Fumes TWA 8 Short Term Beryllium 2.0 g/m 3 25.0 g/m 3 Magnesium Oxide 10.0 mg/m 3 20.0 mg/m 3 Vanadium 50.0 g/m 3 50.0 g/m 3 Chromium 1.0 mg/m 3 3.0 mg/m 3 Manganese (C) 5.0 mg/m 3 5.0 mg/m 3 Nickel 1.0 mg/m 3 3.0 mg/m 3 Cobalt 100.0 g/m 3 500.0 g/m 3 Zinc Oxide 5.0 mg/m 3 10.0 mg/m 3
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Milligrams or Micrograms Per Cubic Meter of Air 1 meter mg or g 1 meter 1 milligram = 1/1,000 gram = 35/1,000,000 oz 1 microgram = 1/1,000,000 gram = 35/1,000,000,000 oz
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How Much is 100 g/m 3 ? 100 g/m 3 = 0.1 ounce per 1,000,000 ft 3
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MSHA Regulations §56/57.5002 §56/57.5002 Dust, Gas, Mist, And Fume Surveys Shall Be Conducted As Frequently As Necessary To Determine The Adequacy Of Control Measures §56/57.5005 §56/57.5005 Control of Harmful Airborne Contaminants Shall Be, Insofar As Feasible, By Engineering Controls l Respirators Permitted Under Certain Circumstances
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MSHA Regulations Part 46 and Part 48 Training §56/57.14213(b) §56/57.14213(b) All Welding Operations Shall Be Well Ventilated §56/57.20011 §56/57.20011 Areas Where Health or Safety Hazards Exist That Are Not Immediately Obvious Shall Be Barricaded Or Warning Signs Posted
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Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls
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Sampling Methods §56/57.5001 §56/57.5002 vFor Compliance With §56/57.5001 And §56/57.5002 vFull Shift Or Short Term
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Sampling Methods §56/57.5001 §56/57.5002 vFor Compliance With §56/57.5001 And §56/57.5002 vFull Shift Or Short Term vSample Pump, Pump Calibrator, Filters
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Sampling Methods §56/57.5001 §56/57.5002 vFor Compliance With §56/57.5001 And §56/57.5002 vFull Shift Or Short Term vSample Pump, Pump Calibrator, Filters vPlace Filter In Breathing Zone Under Hood
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Sampling Methods §56/57.5001 §56/57.5002 vFor Compliance With §56/57.5001 And §56/57.5002 vFull Shift Or Short Term vSample Pump, Pump Calibrator, Filters vPlace Filter In Breathing Zone Under Hood vPump Draws Air Over Filter; Contaminants Captured On Filter
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Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations
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Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations weight of contaminant volume of air
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Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations weight of contaminant mg or g volume of air m 3
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Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations weight of contaminant mg or g volume of air m 3 vMeasured Concentration Compared To Established Exposure Limit
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Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations weight of contaminant mg or g volume of air m 3 vMeasured Concentration Compared To Established Exposure Limit l Measured Less Than Limit - - No Action Req’d
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Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations weight of contaminant mg or g volume of air m 3 vMeasured Concentration Compared To Established Exposure Limit l Measured Less Than Limit - - No Action Req’d l Measured Over Limit - - Implement Controls
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Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls
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Controls (§56/57.5005) vFeasible Engineering Controls vPersonal Protective Equipment (PPE) As Means Of Compliance l PPE Allowed As Means Of Compliance Only In Limited Situations u Where Feasible Engineering Controls Do Not Exist u While Installing Engr. Controls u Occasional Entry Into Hazardous Atmosphere For Maintenance
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Engineering Controls vGeneral Ventilation l Natural or Mechanically Induced (Fans) Airflow Over Work Area That Dilutes and Carries Away Contaminants vLocal Exhaust Ventilation l Captures and Removes Airborne Contaminants Before They Escape Into Workplace Air l Local Exhaust Always Preferred For Toxic Airborne Contaminants
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General Ventilation vOutdoors - Wind vIndoors l Open Shop Doors/Windows l What Blows In, Must Blow Out vFans l Fixed - Roof, Walls, Windows l Portable l Blow Fresh Air Into Work Area, But Don’t Blow Fumes Into Welder’s Breathing Zone l Push-Pull Fan Arrangements l Need Provision For “Make Up” Air
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Local Exhaust Ventilation vCapture Hood & Fixed Duct System
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Local Exhaust Ventilation vPortable “Fume Eliminator”
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Local Exhaust Ventilation vDown Draft Table
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Local Exhaust Ventilation vSystem Must Have Adequate Air Velocity To Draw In Fume Particles l Minimum Capture Velocity 100 ft/min l Better To Design For 200 ft/min vMay Need Provision For “Make Up” Air l 10” Round Duct Drawing 200 ft/min l Air Volume Removed From Work Area Is 110 cfm
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Local Exhaust Ventilation vMust Position Hood Correctly l Air Velocity Drops Rapidly With Distance Away From Hood Opening
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Local Exhaust Ventilation vMust Position Hood Correctly l Air Velocity Drops Rapidly With Distance Away From Hood Opening 10 “ 200 120 60 15 10 inches Air Velocity (ft/min) Hood Opening Airflow
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Respiratory Protection vAir Purifying Or Supplied Air l May Be Integral With Welding Hood vRespirator Use Must Include Implementation of Respiratory Protection Program (See ANSI Z88.2-1969) l Written Procedures on Selection and Use l Respirator Training and Fit Testing l Respirator Inspection, Cleaning, Storage l Workplace Surveillance l Medical Evaluation Recommended
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Welder’s Powered Air Purifying Respirator (PAPR) Half-Mask Cartridge Respirator Supplied-Air Respirator
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Thank You
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