Date post: | 11-Oct-2015 |
Category: |
Documents |
Upload: | sunder-trichy |
View: | 14 times |
Download: | 0 times |
of 33
5/20/2018 Welding Fume Management
1/33
This Presentation is provided to you by:
WPSAmerica.comIndustry Standard Welding Procedures Software for AWS and ASME Codes
5/20/2018 Welding Fume Management
2/33
Welding fume
Management
5/20/2018 Welding Fume Management
3/33
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?
5/20/2018 Welding Fume Management
4/33
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
5/20/2018 Welding Fume Management
5/33
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
5/20/2018 Welding Fume Management
6/33
5/20/2018 Welding Fume Management
7/33
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
5/20/2018 Welding Fume Management
8/33
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
5/20/2018 Welding Fume Management
9/33
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 .
5/20/2018 Welding Fume Management
10/33
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
5/20/2018 Welding Fume Management
11/33
The f i l ter is about the size of a medium
PIZZA!
Clean and used fi l ter , after 30 seconds !
5/20/2018 Welding Fume Management
12/33
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
5/20/2018 Welding Fume Management
13/33
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
5/20/2018 Welding Fume Management
14/33
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
5/20/2018 Welding Fume Management
15/33
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
5/20/2018 Welding Fume Management
16/33
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
5/20/2018 Welding Fume Management
17/33
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
5/20/2018 Welding Fume Management
18/33
Welding fumes
Welding amperage
fume
generationg/min ?
5/20/2018 Welding Fume Management
19/33
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
5/20/2018 Welding Fume Management
20/33
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
5/20/2018 Welding Fume Management
21/33
Fume Concentration
Fume concentration is measured in
Milligrams per cubic meter (mg/m3)
5/20/2018 Welding Fume Management
22/33
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
5/20/2018 Welding Fume Management
23/33
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
5/20/2018 Welding Fume Management
24/33
Air Sampling Meter
5/20/2018 Welding Fume Management
25/33
Daily variation of Fume Concentration
08:00 12:00 16:00
Fume
concentrationmg/m3
Exposure limit
Time weighted
Average
Actual Exposure
5/20/2018 Welding Fume Management
26/33
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!
5/20/2018 Welding Fume Management
27/33
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!!
5/20/2018 Welding Fume Management
28/33
Source capture
5/20/2018 Welding Fume Management
29/33
Appl icat ions?
5/20/2018 Welding Fume Management
30/33
Source capture?
5/20/2018 Welding Fume Management
31/33
Fume extracting gun
5/20/2018 Welding Fume Management
32/33
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
5/20/2018 Welding Fume Management
33/33
Welding Fume management
Quest ions?