This Presentation is provided to you by: WPS America

1. This Presentation is provided to you by: WPSAmerica.com Industry Standard Welding Procedures Software for AWS and ASME Codes

2. Welding fume Management

3. Welding fume Management • In what units is fume generation measured? • What units apply to particulate TLV’s? • 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 CO2 100 20 10 5 0 O2 0 0 5 5 8 1,5 0 80 85 90 92 98,5 Ar

5. 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 I Wire ER 70S3 1,2mm Wire = 10 m/min I = 280 / 300 A U= 32 / 34 V 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

7. Very fine (10E-8 cm) Fine (10E-4 cm) Coarse (1 cm ) Airborne particulates Typical size range 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 ( < 10% of total Chromium) • ANSI/AWS F3.1 - 89 : Guide for Welding Fume Control

18. Welding fumes ? fume generation g/min Welding amperage

19. 100 A 170 A 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 800 600 350 A 400 200 Tension (V) 0 15 20 25 30 35 40 Ar + 10% CO2 Ar + 18% CO2 Ar + 3% CO2 + 1% O2

20. 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

21. Fume Concentration Fume concentration is measured in Milligrams per cubic meter (mg/m3)

22. 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. Air Sampling Meter

25. Daily variation of Fume Concentration Actual Exposure Fume concentration mg/m3 Exposure limit Time weighted Average 08:00 12:00 16:00

26. 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!

27. FUME GENERATION – 1.6 mm FCAW : 200,000 HOURS OF ARC TIMENOTE: 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!!

28. Source capture

29. Applications?

30. Source capture?

31. Fume extracting gun

32. Sample Location Sampling time 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 ON 61 122.1 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 Test results of air quality

33. Welding Fume management Questions?