welding fume management

5/20/2018 Welding Fume Management

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This Presentation is provided to you by:

WPSAmerica.comIndustry Standard Welding Procedures Software for AWS and ASME Codes


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Welding fume

Management


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Welding fume Management

In what uni ts is fume generat ion

measured?

What units apply to particulate TLVs? A FCAW welder produces how much

fumes per year?


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Fume emission level versus shielding atmosphere

100

0

0

20

0

80

10

5

85

5

5

90

0

8

92

0

1,5

98,5

200

400

600

800

1.000

740

470

350290

190150

Fumes (mg /min.)

CO2

O2

Ar

Wire ER 70S3 dia.: 1,2mm280 - 300 A

28 - 30 V


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Ar + 18% CO2

Ar + 13% CO2 + 5% He

Ar + 10% CO2

Ar + 6% CO2 + 2% O2

Ar + 5% CO2 + 4,5% O2

Ar + 3,5% O2

Influence of CO2 content in the shielding gas on CO emissions

0

50

100

150

200

160

130120

80

40

0

CO content (ppm)

Ar+3,5

%O

2

Wire ER 70S3 1,2mm

Wire = 10 m/min

I = 280 / 300 A U= 32 / 34 V

I


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Airborne particulates

Typical size range

Atmospheric dust

Very fin e (10E-8 cm ) Fine (10E-4 cm ) Coars e (1 cm )

Welding fume and dust

Tobacco smoke

Coal dust

Cement dust

Respirable particles


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Factors affecting fume generation rate

Type of shielding gas if applicable to the process

Welding current

Welding voltage

Arc length

Polarity

Current density

Humidity

Base plate

Electrode angle Electrode type

Formulation of the electrode and wire


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Fume emission testing device

Fi lters weighed

befor e and after test

Welding t ime known

30 second s/1 m inexhaust

fume emissio n rate

calcu lated: average

of f ive reading s

measurements inmg/minute

Air exhaust fan

Filters

Conical column

Rotating table

FCAW gun mount

Observation window

AWS F 1.2-92( Laboratory method for measuring fume

generation rates

and total fume emission for Welding and Allied Processes)

20mm plate, 20 inch dia, 4 inch efffective, 120 lbs .


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Typical fume generation

Rates

Process Range g/minSMAW 0.2 - 1.2

FCAW 0.5 - 3.5

GMAW 0.1 - 0.5

GMAW(AL) 0.1 - 1.5


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The f i l ter is about the size of a medium

PIZZA!

Clean and used fi l ter , after 30 seconds !


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Welding fumes composi tion

EEEllleeemmmeeennnttt CCCooommmpppooouuunnndddsss

Fe Fe3O4 - MnFe2O4 - K3FeF6 - CaFeSi2O6

Mn MnFe2O4 - MnSiO3 - MnTiO3

Si Fe2SiO4 - K2SiF6 - CaFeSi2O6

Ti MnTiO3

Ca CaF2 - KCaFe2O4 - CaSiO3

K KCaF3 - K3FeF6 - K2SiF6


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Welding fumes composi tion

EElleemmeenntt CCoommppoouunnddss

Na NaF - NaFeO2

F CaF2 - KCaF3 - K3FeF6 - K2SiF6 - NaF

Ni ( Fe,Ni)O

Cr III Cr 2O3 - FeCr2O4 - K2NaCrF6

Cr VI K2CrO4 - Na2CrO4 - NaK3(CrO4)2


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Potential Health Effects

Fumes Poten tial health hazard Ir on Ox id e Respir ato ry ir ri tan t in h ig h

concentrat ions

Cadmium

ox ide

Lun g irr i tants and kidney toxins

Ch rom ium Cr VI is a r ec ognized car cin ogen

Copper

oxides

Irr i tant, may cause fume fever

Flu or id e A t h ig h exp osu res , lu ng irr i tan t & can

af fect bones and kid neys

Lead Systematic po ison ing and affec ts the

nervous systems

Magnesium

ox ide

Fume fever

Nickel Dermat it is and resp irato ry ir r i tan t

Zinc ox ide Fume fever

Manganese Nervous system disorders Parkinsondisease l ike sym ptom s


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Hexavalent Chrom ium

Hexavalent chrom ium is a known lung

carc inogen

SMAW stainless s teel electrodes produce high

level of Cr VI ( 50% - 70% of to tal chrom ium )

Li th ium compoun ds reduce Cr VI s igni f icant ly

FCAW stainless steel electrod es produce high

level of Cr VI ( 30% - 60% of to tal Chrom ium )

GMAW of s tainless s teel produces very l i t t le

Cr VI ( < 10% of to tal Chrom ium )

ANSI/AWS F3.1 - 89 : Gu ide fo r Welding FumeContro l


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Composit ion by % weight:

GMAW

Element Mild steel StainlessFe 45 - 55 30 - 45

Mn 5 - 10 1 - 20

Si 3 - 5 1 - 4

Ni N/A 2 - 8

Cr Total N/A 8 - 25

Cr VI N/A 0.2 - 1 Li N/A N/A


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Composit ion by % weight:

FCAW

Element Mild steel StainlessFe 30 - 50

10 20Mn 5 - 15 4 - 20

Si 2 4 2 - 8

Ti 0.02 - 4 0.5 - 5

Ca 0 20 0.1 - 5

K 0 - 10 3 - 10 Na 0 - 10 2 - 20

F 1 20 2 - 10

Ni N/A 1 5

Cr Total 6 - 12

Cr VI 1 4Li 0 1


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Welding fumes

Welding amperage

fume

generationg/min ?


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Influence of the shielding gas and parameter set up

on fume emission level in GMAW

(Wire: ER 70S3)

Ar + 3% CO2 + 1% O2 Ar + 10% CO2 Ar + 18% CO2

Tension (V)

15 20 25 30 35 400

200

400

600

800

1.000

170 A

Fumes (mg /min)

300 A

350 A

100 A


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3-D representat ion of fume generat ion

for non pulsed GMAW

For a given wire feed

speed or amperage:

Low fume generation in

short circuit range

As voltage is increased,

transfer transits through

globular range causing a

first maxima

Fine tuning of spray

transfer gives a minima As voltage increased

beyond the optimum,

fume generation rate

increases


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Fume Concentration

Fume concentration is measured in

Milligrams per cubic meter (mg/m3)


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Some terms used in the weld ing fum e legis lat ion

OSHA: Occupational Health and Safety Administration

PEL : Permissible Exposure L imi t (8 hours) TWA: Time weighted average (8 hour exposure)

NI OSH: National I nstitute of Occupational Safety and Health

ACGIH : American Conference of Governmental I ndustr ial Hygienists

OEL : Occupational Exposure Limits (8 hours)

TLV: Thresh hold Limi t Value (8 hours)

TWAEV: Time Weighted Average Exposure Value (8 hours)

STEL: Short Term Exposure L imi t ( TLV-STEL : 15 minutes)

C: Ceil ing value ( TLV-C : instanteneous max value not to be exceeded)

General venti lation must move 2,000 cu feet per minute

Each welder should have 10,000 cu feet of barr ier f ree work space

Serious violation : $ 7,000 per violation Repeat violation: $ 70,000 per violation


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Occupational Exposu re Limits

(OEL) for On tario , CanadaWelding fume 5.0 mg/m3

Chromium Metal 0.5 mg/m3

Chromium - tr ivalent 0.5 mg/m3

Chromium - hexavalent 0.05 mg/m3

Nickel metal 0.5 mg/m3

Manganese 1.0 m /m3 0.2 m /m3

Fluorides 2.5 mg/m3

Barium soluble 0.5 mg/m3

NO2 3.0 ppm

NO 25 ppm Ozone 0.1 ppm

CO 35 ppm


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Air Sampling Meter


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Daily variation of Fume Concentration

08:00 12:00 16:00

Fume

concentrationmg/m3

Exposure limit

Time weighted

Average

Actual Exposure


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Fume weigh t per welder per year ?

Fume generat ion rate of 1g/minu te

2000 hours/yr at 20% duty cycle = 400 hou rs w elding t ime

400 hou rs X 1 g /m inu te X 60 = 24,000 grams = 52.8 pou nd s

Equal to the weigh t of one coi l of wire per year!


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FUME GENERATION1.6 mm FCAW : 200,000 HOURS OF ARC TIME

NOTE: 200,000 hours of arc time at 18% duty cycle translates to

approximately 556 welders.

STA TUS W IRE Fum e g /m in W i re feed i .p .m VOLTAGE GA S Fum e Burden

Curren t Wire A 1.066 35 0 29 V CO2 12.79 MT

Proposed Wire B 0.783 380 29 V B/S8 9.39 MT Proposed Wire A 0.881 380 29 V B/S8 10.57 MT

Proposed Wire C 0.949 380 29 V B/S8 11.38 MT

Benchmark Wire B 0.67 350 29 V A rcal 211 8.04 MT

Through choice of gas and wire fumes reduced

Annually by 4.75 MT!!


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Source capture


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Appl icat ions?


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Source capture?


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Fume extracting gun


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Test results of air quality

Sample Location Samplingtime in

minutes

Volume

sampled

in

liters

Lab results

(micro

grams per

sample)

Concentration

(mg/m3)

99V001 Welder under general

exhaust fume hood,

fume hood switched

OFF

61 122.1 3424 28.0

99V002 Welder under general

exhaust, fume hood

switched ON61 122.1 1969 16.1

99V003 Welder under fume

hood, with a smoke

extracting gun 62 122.4 171 1.38

Ontario Ministry of Labour, TWAEV for welding fumes 5.00


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Welding Fume management

Quest ions?

welding fume management

Documents

fume feverflu

fume emission level

test welding t ime known30

coars e

resp irato ry ir r i

k3fef6 k2sif6

t h ig h exp osu res

o2influence of co2 content