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This Presentation is provided to you by: WeldCanada.com Industry Standard Welding Procedures Software CSA, AWS, ASME and API Welding Codes

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... Potential Health Effects Hexavalent Chromium Welding fumes 3-D representation of fume generation for non pulsed GMAW For a given wire feed speed or amperage: ... – PowerPoint PPT presentation

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Title: This Presentation is provided to you by: WeldCanada.com Industry Standard Welding Procedures Software CSA, AWS, ASME and API Welding Codes


1
This Presentation is provided to you by
WeldCanada.com Industry Standard Welding
Procedures Software CSA, AWS, ASME and API
Welding Codes
2
Welding fume Management

3
Welding fume Management
  • In what units is fume generation measured?
  • What units apply to particulate TLVs?
  • A FCAW welder produces how much fumes per year?

4
Fume emission level versus shielding atmosphere
Fumes (mg/min.)
1.000
Wire ER 70S3 dia. 1,2mm
280 - 300 A
800
740
28 - 30 V
600
470
400
350
290
190
200
150
0
100
20
10
5
0
CO2
O2
0
0
5
5
8
1,5
0
80
85
90
92
98,5
Ar
5
Influence of CO2 content in the shielding gas on
CO emissions
CO content (ppm)
200
160
150
130
120
100
80
Ar 3,5 O2
50
40
0
0
6
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7
  • Airborne particulates
  • Typical size range

Very fine (10E-8 cm) Fine (10E-4 cm)
Coarse (1 cm )
Atmospheric dust
Welding fume and dust
Tobacco smoke
Coal dust
Cement dust
Respirable particles
8
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

9
Fume emission testing device
  • Filters weighed before and after test
  • Welding time known
  • 30 seconds/1 min exhaust
  • fume emission rate calculated average of five
    readings
  • measurements in mg/minute
  • Air exhaust fan
  • Filters
  • Conical column
  • Observation window
  • Rotating table
  • FCAW gun mount
  • 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 .

10
  • Typical fume generation Rates

Process
Range g/min
SMAW
0.2 - 1.2
FCAW
0.5 - 3.5
GMAW
0.1 - 0.5
GMAW(AL)
0.1 - 1.5
11
The filter is about the size of a medium PIZZA!
  • Clean and used filter, after 30 seconds!

12
Welding fumes composition
13
Welding fumes composition
14
Potential Health Effects
15
  • Hexavalent Chromium
  • Hexavalent chromium is a known lung carcinogen
  • SMAW stainless steel electrodes produce high
    level of Cr VI ( 50 - 70 of total chromium)
  • Lithium compounds reduce Cr VI significantly
  • FCAW stainless steel electrodes produce high
    level of Cr VI ( 30 - 60 of total Chromium)
  • GMAW of stainless steel produces very little
    Cr VI ( lt 10 of total Chromium)
  • ANSI/AWS F3.1 - 89 Guide for Welding Fume
    Control

16
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17
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18
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19
  • Welding fumes

?
fume generation g/min
Welding amperage
20
Influence of the shielding gas and parameter set
up on fume emission level in GMAW
(Wire ER 70S3)
Fumes (mg/min)
1.000
300 A
800
600
400
350 A
200
Tension (V)
0
15
20
25
30
35
40
Ar 10 CO2
Ar 18 CO2
Ar 3 CO2 1 O2
21
3-D representation of fume generation 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

22
  • Fume Concentration

Fume concentration is measured in Milligrams per
cubic meter (mg/m3)
23
Some terms used in the welding fume legislation
  • OSHA Occupational Health and Safety
    Administration
  • PEL Permissible Exposure Limit (8 hours)
  • TWA Time weighted average (8 hour exposure)
  • NIOSH National Institute of Occupational Safety
    and Health
  • ACGIH American Conference of Governmental
    Industrial Hygienists
  • OEL Occupational Exposure Limits (8 hours)
  • TLV Thresh hold Limit Value (8 hours)
  • TWAEV Time Weighted Average Exposure Value (8
    hours)
  • STEL Short Term Exposure Limit ( TLV-STEL 15
    minutes)
  • C Ceiling value ( TLV-C instanteneous max
    value not to be exceeded)
  • General ventilation must move 2,000 cu feet per
    minute
  • Each welder should have 10,000 cu feet of
    barrier free work space
  • Serious violation 7,000 per violation
  • Repeat violation 70,000 per violation

24
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25
Air Sampling Meter
26
  • Daily variation of Fume Concentration

Actual Exposure
Fume concentration mg/m3
Exposure limit Time weighted Average
0800 1200
1600
27
Fume generation rates FCAW SMAW
28
GMAW values Typical fume generation rates at 260
amps
29
MCAW values Typical fume generation rates at 260
amps
30
FCAW values Typical fume generation rates at 260
amps
31
Fume weight per welder per year ?
  • Fume generation rate of 1g/minute
  • 2000 hours/yr at 20 duty cycle 400 hours
    welding time
  • 400 hours X 1 g/minute X 60 24,000 grams 52.8
    pounds
  • Equal to the weight of one coil of wire per year!

32
FUME GENERATION 1.6 mm FCAW 200,000 HOURS OF
ARC TIME NOTE 200,000 hours of arc time at
18 duty cycle translates to approximately 556
welders.
33
FUME GENERATION 1.6 mm FCAW 200,000 HOURS OF
ARC TIME NOTE 200,000 hours of arc time at
18 duty cycle translates to approximately 556
welders.
Through choice of gas and wire fumes
reduced Annually by 4.75 MT!!
34
Influence of pulsed current on fume emission level
ER 70S3 1,2mm / ARCAL14
Fumes (mg/min)
800
Arcal 14
Arcal 14 pulsed
600
400
200
0
100
170
240
300
350
Amperage (A)
35
FUME EMISSION LEVEL
Metal Cored Wire
Rutile FCW for all positions
Fume emission level (g/min)
Fume emission level (g/min)
1,2
1,2
1,05
1
1
0,8
0,8
0,57
0,6
0,6
0,52
0,37
0,4
0,4
0,2
0,2
0
0
GREEN 101
SD100
SD206
SD207
ARCAL 22
ARCAL 22
ATAL 5
ATAL 5
Parameter set up I 250 A U 26 V
36
Source capture
37
Applications?
38
Source capture?
39
Fume extracting gun
40
Test results of air quality
41
Welding Fume management
  • Questions?
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