Welding Fumes

7/27/2019 Welding Fumes

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Welding Fumes

What Are Welding Fumes ?

Health HazardsMSHA Regulations

Sampling MethodsControls


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Welding Fumes





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How Big Is A Micron ?


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Head of Pin

1/32 Inch


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Head of Pin20 Microns20 Microns

1/32 Inch


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Size Comparison of Small Particles

mWashed Foundry Sand 200 to 2,000

Plant Spores 10.0 to 40Red Blood Cells 7Cement Dust 1.0 to 10Bacteria 1/10 to 10Tobacco Smoke 1/100 to 1/2

Metal Fumes 1/1,000 to 1.0


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Composition of Welding Fumes

Composition Varies Depending On:Material Being WeldedWelding Process, Rod, Electrode TypeObtain MSDS From Manufacturer

Typical Welding Fume Constituents:Aluminum, Cadmium, Chromium, Iron, Moly

Cobalt, Copper, Zinc, Manganese, Tin, LeadNickel, Arsenic, Mercury, Vanadium,Beryllium, Magnesium, Titanium,

May Be Metal or Oxide


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Welding Fumes


Health Hazards MSHA Regulations



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Exposure Primarily By Inhalation


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Exposure Primarily By InhalationFumes Are 100% RespirableWhat Does Respirable Mean ?


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Exposure Primarily By InhalationFumes Are 100% RespirableWhat Does Respirable Mean ?


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Welding Fume Toxicity

Acute ToxicityExposure To High ConcentrationOver Relatively Short TimeSymptoms Appear Relatively QuicklyAfter Exposure

Chronic Toxicity

Exposure To Lower ConcentrationOver Long Time (Months, Years)Symptoms Appear Long After Initial

Exposure


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Exposure Usually Involves MoreThan One MetalToxic Effects May Be Additive Additive

ExamplesBlood - Manganese and LeadCNS - Manganese and LeadKidney - Lead and CadmiumRespiratory System - Magnesium,Manganese, Copper, and Zinc


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Metal Fume Fever Symptoms Are Fever, Chills, ShakingSymptoms Appear 4-12 Hrs After Exp.

Recovery Usually Within 1 DayUsually Associated With Brief HighInhalation Exposure To Zinc, But

Magnesium & Copper Also May CauseDaily Exposure May Confer ImmunitySymptoms May Return If Exposure

Interrupted (3-Day Weekend)


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Welding Fume ToxicityWelding Fumes Can Cause Cancer

Arsenic (Lung, Lymphatic)Beryllium (Lung)Cadmium (Prostatic and Lung)

Chromium (Lung)Nickel (Lung)

Welders May Also Be Exposed To:

Silica, Asbestos, OzoneThermal 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


Health Hazards MSHA Regulations

Sampling Methods Controls


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MSHA Regulations

56/57.5001 56/57.5001 Establishes ExposureLimits For Airborne Contaminants

TWA 8 And Ceiling Limits Listed In

1973 ACGIH Booklet of ThresholdLimit Values (TLVs)

TWA 8 Time Weighted Average For 8 Hrs

Ceiling Limits Cannot Be Exceeded For Any Length Of Time

ACGIH 1973 TLV Booklet References

1968 PA Rules For Short Term Limits


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Exposure Limits For CommonWelding 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/m3

10.0 mg/m3


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Milligrams or MicrogramsPer Cubic Meter of Air

1 meter 1 meter

1 meter 1 meter

mgor

g

1 meter 1 meter

1 milligram = 1/1,000 gram = 35/1,000,000 oz1 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 FumeSurveys Shall Be Conducted AsFrequently As Necessary To Determine

The Adequacy Of Control Measures

56/57.5005 56/57.5005 Control of Harmful Airborne

Contaminants Shall Be, Insofar AsFeasible, By Engineering ControlsRespirators Permitted Under Certain

Circumstances


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MSHA Regulations

Part 46 and Part 48 Training Part 46 and Part 48 Training 56/57.14213(b)56/57.14213(b) All WeldingOperations Shall Be Well Ventilated

56/57.2001156/57.20011 Areas Where Healthor Safety Hazards Exist That AreNot Immediately Obvious Shall BeBarricaded Or Warning SignsPosted


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Sampling MethodsFor Compliance With 56/57.500156/57.5001 And56/57.5002 56/57.5002 Full Shift Or Short Term


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Sampling MethodsFor Compliance With 56/57.500156/57.5001 And56/57.5002 56/57.5002 Full Shift Or Short TermSample Pump, Pump Calibrator, Filters


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Place Filter In Breathing Zone Under Hood


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Place Filter In Breathing Zone Under Hood

Pump Draws Air Over Filter;


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Sampling Methods

Analytic Lab Determines Weights Of Individual Contaminants On Filter Weights Converted To Concentrations


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Sampling Methods


weight of contaminantvolume of air


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Sampling Methods


weight of contaminant mg or gvolume of air m 3


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Sampling Methods



Measured Concentration Compared ToEstablished Exposure Limit


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Sampling Methods



Measured Concentration Compared ToEstablished Exposure LimitMeasured Less Than Limit - - No Action Reqd


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Sampling Methods



Measured Concentration Compared ToEstablished Exposure LimitMeasured Less Than Limit - - No Action Reqd

Measured Over Limit - - Implement Controls


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Welding Fumes





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Controls (56/57.5005)

Feasible Engineering ControlsPersonal Protective Equipment (PPE)

PPE Allowed As Means Of Compliance As Means Of Com pliance Only In Limited SituationsWhere Feasible Engineering ControlsDo Not ExistWhile Installing Engr. ControlsOccasional Entry Into Hazardous

Atmosphere For Maintenance


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General VentilationOutdoors - WindIndoors

Open Shop Doors/WindowsWhat Blows In, Must Blow Out

FansFixed - Roof, Walls, WindowsPortableBlow Fresh Air Into Work Area, But Dont BlowFumes Into Welders Breathing ZonePush-Pull Fan Arrangements

Need Provision For Make Up Air


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Local Exhaust Ventilation

Capture Hood & Fixed Duct System


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Down Draft Table


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System Must Have Adequate Air Velocity To Draw In Fume Particles

Minimum Capture Velocity 100 ft/min

Better To Design For 200 ft/minMay Need Provision For Make Up Air

10 Round Duct Drawing 200 ft/minAir Volume Removed From Work AreaIs 110 cfm


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Must Position Hood CorrectlyAir Velocity Drops Rapidly With DistanceAway From Hood Opening


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Must Position Hood CorrectlyAir Velocity Drops Rapidly With DistanceAway From Hood Opening

10 200 120 60 15

10 inches

Air Velocity (ft/min)

Hood Opening

Airflow


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Respiratory ProtectionAir Purifying Or Supplied Air

May Be Integral With Welding Hood

Respirator Use Must IncludeImplementation of Respiratory ProtectionProgram (See ANSI Z88.2-1969)

Written Procedures on Selection and UseRespirator Training and Fit TestingRespirator Inspection, Cleaning, StorageWorkplace SurveillanceMedical Evaluation Recommended


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Welders PoweredAir PurifyingRespirator (PAPR)

Half-Mask CartridgeRespirator

Supplied-Air Respirator


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Thank You

Documents

Welding Fumes