Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls

Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls

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

How Big Is A Micron ?

Head of Pin 1/32 Inch

How Big Is A Micron ? Head of Pin 20 Microns 1/32 Inch

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

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

Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls

Exposure Primarily By Inhalation

Exposure Primarily By Inhalation Fumes Are 100% Respirable

Exposure Primarily By Inhalation Fumes Are 100% Respirable What Does “Respirable” Mean ?

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

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

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

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)

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.)

Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls

MSHA Regulations § 56/ § 56/ 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

Exposure Limits For Common Welding Fumes TWA 8 Short Term Beryllium 2.0  g/m  g/m 3 Magnesium Oxide 10.0 mg/m mg/m 3 Vanadium 50.0  g/m  g/m 3 Chromium 1.0 mg/m mg/m 3 Manganese (C) 5.0 mg/m mg/m 3 Nickel 1.0 mg/m mg/m 3 Cobalt  g/m  g/m 3 Zinc Oxide 5.0 mg/m mg/m 3

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

How Much is 100  g/m 3 ? 100  g/m 3 = 0.1 ounce per 1,000,000 ft 3

MSHA Regulations §56/ §56/ Dust, Gas, Mist, And Fume Surveys Shall Be Conducted As Frequently As Necessary To Determine The Adequacy Of Control Measures §56/ §56/ Control of Harmful Airborne Contaminants Shall Be, Insofar As Feasible, By Engineering Controls l Respirators Permitted Under Certain Circumstances

MSHA Regulations Part 46 and Part 48 Training §56/ (b) §56/ (b) All Welding Operations Shall Be Well Ventilated §56/ §56/ Areas Where Health or Safety Hazards Exist That Are Not Immediately Obvious Shall Be Barricaded Or Warning Signs Posted

Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls

Sampling Methods §56/ §56/ vFor Compliance With §56/ And §56/ vFull Shift Or Short Term

Sampling Methods §56/ §56/ vFor Compliance With §56/ And §56/ vFull Shift Or Short Term vSample Pump, Pump Calibrator, Filters

Sampling Methods §56/ §56/ vFor Compliance With §56/ And §56/ vFull Shift Or Short Term vSample Pump, Pump Calibrator, Filters vPlace Filter In Breathing Zone Under Hood

Sampling Methods §56/ §56/ vFor Compliance With §56/ And §56/ 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

Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations

Sampling Methods vAnalytic Lab Determines Weights Of Individual Contaminants On Filter vWeights Converted To Concentrations weight of contaminant volume of air

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

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

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

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

Welding Fumes v What Are Welding Fumes ? v Health Hazards v MSHA Regulations v Sampling Methods v Controls

Controls (§56/ ) 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

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

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

Local Exhaust Ventilation vCapture Hood & Fixed Duct System

Local Exhaust Ventilation vPortable “Fume Eliminator”

Local Exhaust Ventilation vDown Draft Table

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

Local Exhaust Ventilation vMust Position Hood Correctly l Air Velocity Drops Rapidly With Distance Away From Hood Opening

 Local Exhaust Ventilation vMust Position Hood Correctly l Air Velocity Drops Rapidly With Distance Away From Hood Opening 10 “ inches Air Velocity (ft/min) Hood Opening Airflow

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 Z ) 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

Welder’s Powered Air Purifying Respirator (PAPR) Half-Mask Cartridge Respirator Supplied-Air Respirator

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