Welding Fumes (Long)

7/28/2019 Welding Fumes (Long)

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Welding Fumes

What Are Welding Fumes ?

Health Hazards MSHA Regulations

Sampling Methods Controls


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Welding Fumes





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Welding Causes Solid Metal To VaporizeAs Vaporized Metal Cools, It Condenses

To Reform As Solid Particles - FUME

Fumes Are Very Small Particles - -Usually Much Smaller Than Dust

Dust Usually Larger Than 1 Micron

Fumes Can Be As Small As 1/1,000 MicronUnless 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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Head of Pin20 Microns

1/32 Inch


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Size Comparison of Small Particles

mWashed Foundry Sand 200 to2,000

Plant Spores 10.0 to40Red Blood Cells 7

Cement Dust 1.0 to10

Bacteria 1/10 to10

Tobacco Smoke 1/100 to1/2

Metal Fumes 1/1,000 to1.0


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Composition of Welding Fumes

Composition Varies Depending On: Material Being Welded

Welding Process, Rod, Electrode Type

Obtain MSDS From Manufacturer

Typical Welding Fume Constituents:

Aluminum, Cadmium, Chromium, Iron, Moly

Cobalt, Copper, Zinc, Manganese, Tin, Lead

Nickel, Arsenic, Mercury, Vanadium,

Beryllium, Magnesium, Titanium,

May Be Metal or Oxide


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Welding Fumes


Health HazardsMSHA Regulations



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Exposure Primarily By Inhalation


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Fumes Are 100% Respirable


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What Does Respirable Mean ?


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What Does Respirable Mean ?


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Welding Fume Toxicity

Acute Toxicity

Exposure To High Concentration Over

Relatively Short Time

Symptoms Appear Relatively Quickly

After Exposure

Chronic Toxicity

Exposure To Lower ConcentrationOver Long Time (Months, Years)

Symptoms Appear Long After Initial

Exposure


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Kidney Nervous Liver GI Lung

Aluminum X X

Beryllium X

Cadmium X X X X

Chromium X X X XCobalt 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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Exposure Usually Involves MoreThan One Metal

Toxic Effects May Be Addi t ive

ExamplesBlood - Manganese and Lead

CNS - Manganese and Lead

Kidney - Lead and Cadmium

Respiratory System - Magnesium,

Manganese, Copper, and Zinc


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Metal Fume Fever

Symptoms Are Fever, Chills, Shaking

Symptoms Appear 4-12 Hrs After Exp.

Recovery Usually Within 1 DayUsually Associated With Brief High

Inhalation Exposure To Zinc, But

Magnesium & Copper Also May CauseDaily Exposure May Confer Immunity

Symptoms May Return If Exposure

Interrupted (3-Day Weekend)


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Welding 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, Ozone Thermal Decomposition of Paint, Flux,

Electrode Coatings (CO, CO2, NO, NO2, HCN,

COCl2, Fluoride Gases, Smoke, Etc.)


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Welding Fumes


Health HazardsMSHA Regulations

Sampling MethodsControls


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MSHA Regulations

56/57.5001Establishes ExposureLimits For Airborne Contaminants

TWA8 And Ceiling Limits Listed In

1973 ACGIH Booklet of ThresholdLimit Values (TLVs)

TWA8 Time Weighted Average For 8 Hrs

Ceiling Limits Cannot Be Exceeded ForAny Length Of Time

ACGIH 1973 TLV Booklet References

1968 PA Rules For Short Term Limits


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Exposure Limits For Common

Welding FumesTWA8 Short Term

Beryllium 2.0g/m3 25.0g/m3

Magnesium Oxide 10.0 mg/m3 20.0 mg/m3

Vanadium 50.0g/m3 50.0g/m3

Chromium 1.0 mg/m3

3.0 mg/m3

Manganese (C) 5.0 mg/m3 5.0 mg/m3

Nickel 1.0 mg/m3 3.0 mg/m3

Cobalt 100.0 g/m3 500.0g/m33 3


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Milligrams or Micrograms

Per Cubic Meter of Air

1 meter

1 meter

mgor

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 100g/m3 ?

100g/m3 = 0.1 ounce per 1,000,000 ft3


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MSHA Regulations

56/57.5002Dust, Gas, Mist, And FumeSurveys Shall Be Conducted As

Frequently As Necessary To Determine

The Adequacy Of Control Measures

56/57.5005Control of Harmful Airborne

Contaminants Shall Be, Insofar AsFeasible, By Engineering Controls

Respirators Permitted Under Certain

Circumstances


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MSHA Regulations

Part 46 and Part 48 Train ing

56/57.14213(b) All Welding

Operations Shall Be Well Ventilated56/57.20011 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



Sampling MethodsControls


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Sampling Methods

For Compliance With 56/57.5001And

56/57.5002

Full Shift Or Short Term


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Sampling Methods


56/57.5002


Sample Pump, Pump Calibrator, Filters


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Sampling Methods


56/57.5002



Place Filter In Breathing Zone Under

Hood


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Sampling Methods


56/57.5002



Place Filter In Breathing Zone Under

Hood

Pump Draws Air Over Filter;


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Sampling Methods

Analytic Lab Determines Weights OfIndividual Contaminants On Filter

Weights Converted To Concentrations


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Sampling Methods



weight of contaminant

volume of air


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Sampling Methods



weight of contaminant mg orgvolume of air m3


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Sampling Methods




Measured Concentration Compared ToEstablished Exposure Limit


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Sampling Methods





Measured Less Than Limit - - No Action Reqd


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Sampling Methods





Measured 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 Controls

Personal Protective Equipment (PPE)

PPE Allowed As Means Of Compl iance

Only In Limited Situations

Where Feasible Engineering Controls

Do Not Exist

While Installing Engr. Controls

Occasional Entry Into Hazardous

Atmosphere For Maintenance


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Engineering Controls

General VentilationNatural or Mechanically Induced (Fans)

Airflow Over Work Area That Dilutes

and Carries Away ContaminantsLocal Exhaust Ventilation

Captures and Removes Airborne

Contaminants Before They Escape IntoWorkplace Air

Local Exhaust Always Preferred For

Toxic Airborne Contaminants


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General VentilationOutdoors - Wind

Indoors

Open Shop Doors/Windows

What Blows In, Must Blow Out

Fans

Fixed - Roof, Walls, Windows

Portable

Blow Fresh Air Into Work Area, But Dont Blow

Fumes Into Welders Breathing Zone

Push-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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Portable Fume Eliminator


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Down Draft Table


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System Must Have Adequate AirVelocity 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/min

Air Volume Removed From Work Area

Is 110 cfm


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Must Position Hood Correctly Air Velocity Drops Rapidly With Distance

Away From Hood Opening


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Must Position Hood Correctly Air Velocity Drops Rapidly With Distance

Away From Hood Opening

10200 120 60 15

10 inches

Air Velocity (ft/min)

Hood Opening

Airflow


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Respiratory Protection

Air Purifying Or Supplied Air

May Be Integral With Welding Hood

Respirator Use Must Include

Implementation of Respiratory Protection

Program (See ANSI Z88.2-1969)

Written Procedures on Selection and Use

Respirator Training and Fit Testing

Respirator Inspection, Cleaning, Storage

Workplace Surveillance

Medical Evaluation Recommended


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Welders Powered

Air Purifying

Respirator(PAPR) Half-Mask CartridgeRespirator Supplied-AirRespirator


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Thank You

Documents

Welding Fumes (Long)