California Code of Regulations › Title 17 - Public Health › Division 3 - Air Resources › Chapter 1 - Air Resources Board › Subchapter 7.5 - Airborne Toxic Control Measures › Appendix 1 - Emission Calculation Method

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
Emissions of hexavalent chromium (Cr +6) and nickel (Ni)
					 from thermal spraying operations must be calculated in accordance with the
					 procedures specified in this Appendix 1.
Step 1: Identify all thermal spraying materials that
					 contain chromium (Cr) or nickel (Ni) at a concentration of at least 0.1% by
					 weight (or less than 0.1%, if listed on the Material Safety Data Sheet.)
					 Include materials that contain chromium or nickel in the form of a metallic
					 compound or alloy. Examples of compounds and alloys include, but are not
					 limited to, stainless steel; chromium carbide (Cr 3 C
					 2); nichrome alloys (NiCr); and chromium oxide (Cr
					 2 O 3).
Step 2: Determine the total percentage of chromium and/or
					 nickel contained in each thermal spraying material. These data can be obtained
					 from the material safety data sheet (MSDS) or by contacting the manufacturer.
					 If the MSDS contains a range of percentages, use the upper value of the range.
					 If the material contains a compound (e .g., Cr 3 C
					 2), include only the portion that is chromium or
					 nickel.
Step 3: For each thermal spraying operation, compile the
					 annual usage for each thermal spraying material that contains chromium or
					 nickel. For thermal spraying operations that have air permits, the annual usage
					 is the maximum allowable under the permit.
Step 4: For each thermal spraying operation, calculate the
					 annual usage quantities for chromium and nickel using the following
					 equations:
Eqn. 1: [Annual Usage, lbs Cr/yr] = [Material Usage, lbs
					 material used/yr]*[weight % Cr in Material]
Eqn. 2: [Annual Usage, lbs Ni/yr] = [Material Usage, lbs
					 material used/yr]*[weight % Ni in Material]
Step 5. Identify the applicable emission factor(s) for each
					 thermal spraying operation, based on the applicable control efficiency level.
					 If a material is used for multiple thermal spraying operations and material
					 usage records document the quantity of material used for each operation, use
					 the applicable emission factors for each operation. If material usage records
					 do not document the quantity of material used for each operation, use the
					 highest emission factor.
Table 1-1 specifies the applicable emission factors for
					 thermal spraying operations using materials that contain chromium, chromium
					 compounds, or chromium alloys.
Table 1-2 specifies the applicable emission factors for
					 thermal spraying operations using materials that contain nickel, nickel
					 compounds, or nickel alloys.
Table 1-1: Thermal Spraying Emission Factors for Hexavalent
					 Chromium
Emission Factors (lbs Cr+6/lb Cr sprayed)*
0%
90%
99%
99.97%
Operation
Control Efficiency
Control Efficiency
Control Efficiency
Control Efficiency
(Uncontrolled)
(e.g. Water Curtain)
(e.g. Dry Filter)
(e.g., HEPA Filter)
Single-Wire Flame Spray
4.68E-03
4.68E-04
4.68E-05
1.40E-06
Twin-Wire Electric Arc Spray
6.96E-03
6.96E-04
6.96E-05
2.09E-06
Flame Spray
6.20E-03
1.17E-03
6.20E-05
1.86E-06
HVOF
6.20E-03
1.17E-03
6.20E-05
1.86E-06
Plasma Spray
1.18E-02
6.73E-03
2.61E-03
2.86E-06
Other Thermal Spraying
7.17E-03
2.05E-03
5.70E-04
2.01E-06
Image
*Some emission factors are based directly on stack test
					 results while others are calculated values, derived from stack test results and
					 control efficiencies.
Table 1-2: Thermal Spraying Emission Factors for
					 Nickel
Emission Factors (lbs Ni/lb Ni sprayed)*
0%
90%
99%
99.97%
Operation
Control Efficiency
Control Efficiency
Control Efficiency
Control Efficiency
(Uncontrolled)
(e.g. Water Curtain)
(e.g. Dry Filter)
(e.g., HEPA Filter)
Twin-Wire Electric Arc Spray
6.0E-03
6.0E-04
6.0E-05
1.8E-06
Flame Spray
1.10E-01
4.64E-02
1.10E-03
3.30E-05
HVOF
1.10E-01
4.64E-02
1.10E-03
3.30E-05
Plasma Spray
1.5E-01
3.67E-02
1.5E-03
1.72E-05
Other Thermal Spraying
9.4E-02
3.25E-02
9.4E-04
2.13E-05
Image
*Some emission factors are based directly on stack test
					 results while others are calculated values, derived from stack test results and
					 control efficiencies.
Step 6 - Annual Emissions. For each thermal spraying
					 operation, calculate the annual emissions by multiplying the applicable
					 emission factors by the annual usage rates, using the following
					 equations:
Eqn. 3: [Annual Emissions, lbs Cr +6/ yr] = [Emission
					 Factor, lbs Cr +6/ lb Cr sprayed]*[Annual Usage, lbs Cr sprayed/yr]]
Eqn. 4: [Annual Emissions, lbs Ni/yr] = [Emission Factor,
					 lbs Ni/lb Ni sprayed]*[Annual Usage, lbs Ni sprayed/yr]
Step 7 - Maximum Hourly Nickel Emissions: For each thermal
					 spraying operation that uses nickel, calculate the maximum hourly emissions by
					 multiplying the applicable emission factors by the maximum hourly usage rates,
					 using the following equations:
Eqn. 5: [Max. Hourly Emissions, lbs Ni/hr] = [Emission
					 Factor, lbs Ni/lb Ni sprayed]*[Max. Hourly Usage, lbs Ni sprayed/hr]
Eqn. 6: [Max. Hourly Usage, lbs Ni sprayed/hr] = [Max. Gun
					 Spray Rate, lbs material sprayed/hr]*[Max. wt.% Ni in material]
where
"Maximum Gun Spray Rate" is the highest material throughput
					 rate that a thermal spraying gun can achieve, based on manufacturer
					 specifications or actual user experience, whichever is greater. If multiple
					 guns have the potential to be operated at the same time (e.g., in two separate
					 booths), the maximum gun spray rate must include the total throughput from all
					 guns.
"Maximum Weight % Nickel in Material" is the highest weight
					 percentage of nickel for all of the thermal spraying materials that are used in
					 thermal spraying operations at a facility.
Point Source Example:
Thermal Spraying Inc. operates two thermal spraying booths.
					 One booth is used for plasma spraying and the other booth is used for flame
					 spraying and twin-wire electric arc spraying. Listed below is information on
					 the facility's operations:
Booth
Control Device
Operation
Materials Used
Quantity Used
% Total Chromium
% Nickel
Booth 1
HEPA Filter
Plasma Spray
Powder ABC
25 lbs/yr
25%
0%
Powder XYZ
50 lbs/yr
20%
75%
Booth 2
Dry Filter
Flame Spray
Powder 123
10 lbs/yr
0%
95%
(99% effic.)
Powder XYZ
75 lbs/yr
20%
75%
Twin-Wire
Wire 1
80 lbs/yr
20%
5%
Image
An example calculation is provided below for Thermal
					 Spraying Inc.:
Step 1: Identify all thermal spraying materials that
					 contain at least 0.1% by weight of chromium (Cr), chromium compounds, nickel
					 (Ni), or nickel compounds.
The following four products contain chromium or nickel:
					 Powder 123; Powder ABC; Powder XYZ; Wire #1.
Step 2: Determine the total percentage of chromium and/or
					 nickel .
Materials Used
% Total Chromium
% Nickel
Powder 123
0%
95%
Powder ABC
25%
0%
Powder XYZ
20%
75%
Wire 1
20%
5%
Image
If a thermal spraying material contains a compound, include
					 only the portion that is chromium or nickel. For example, if the material
					 contains 95% chromium oxide (Cr 2 O
					 3), the weight percent of chromium would be calculated
					 as follows:
[Chromium Weight %]=[Weight % Cr2O3]*
[Molecular Weight of Chromium (Cr2)] /
[Molecular Weight of Chromium Oxide (Cr2O3)]
Molecular Weight of Chromium (Cr2) = (52 g/g-mol)*(2) = 104
					 g/g-mol Molecular Weight of Chromium Oxide (Cr2O3) = (52 g/g-mol)*(2)+(16)*(3)
					 = 152 g/g-mol [Chromium Weight %]=[95 % Cr2O3]*
[104 g/g-mol] / [152 g/g-mol] =65%
Step 3: Compile the annual material usage.
Operation
Materials Used
Quantity Used
Plasma Spray
Powder ABC
25 lbs/yr
Powder XYZ
50 lbs/yr
Flame Spray
Powder 123
10 lbs/yr
Powder XYZ
75 lbs/yr
Twin-Wire
Wire 1
80 lbs/yr
Step 4: Calculate the annual usage quantities for chromium
					 and nickel.
Materials Used
Quantity Used
% Total Chromium
% Nickel
Qty. of Total Chromium Used
Qty. of Nickel Used
Powder ABC
25 lbs/yr
25%
0%
[25 lbs/yr]x[25% Cr] =
[25 lbs/yr]x[ 0% Ni] =
6.25 lbs Cr/yr
0 lbs Ni/yr
Powder XYZ
50 lbs/yr
20%
75%
[50 lbs/yr]x[20% Cr] =
[50 lbs/yr]x[75% Ni] =
10.0 lbs Cr/yr
37.5 lbs Ni/yr
Powder 123
10 lbs/yr
0%
95%
[10 lbs/yr]x[0% Cr] =
[10 lbs/yr]x[9 5% Ni] =
0 lbs Cr/yr
9.5 lbs Ni/yr
Powder XYZ
75 lbs/yr
20%
75%
[75 lbs/yr]x[20% Cr] =
[75 lbs/yr]x[75% Ni] =
15.0 lbs Cr/yr
56.25 lbs Ni/yr
Wire 1
80 lbs/yr
20%
5%
[80 lbs/yr]x[20% Cr] =
[80 lbs/yr]x[5 % Ni] =
16.0 lbs Cr/yr
4.0 lbs Ni/yr
Image
Step 5: Identify the applicable emission factors.
Emission Factor - Hexavalent
								Chromium
Emission Factor - Nickel
Control Device
Operation
(lb Cr+6/Cr sprayed)
(lb Ni/lb Ni sprayed)
HEPA Filter
Plasma Spray
2.86E-06
1.72E-05
Dry Filter
Flame Spray
6.20E-05
1.10E-03
(99% effic.)
Twin-Wire
6.96E-05
6.0E-05
Image
Step 6: Calculate annual emissions ([Annual Emissions] =
					 [Emission Factor]*[Annual Usage].)
For hexavalent chromium, the annual emissions are -
Qty. of Total
Emission Factor
Chromium Used
(lb Cr+6/lb
Annual Emissions
Booth
Control Device
Operation
Materials Used
(lbs Cr sprayed/yr)
Cr sprayed)
(lb Cr+6/yr)
1
HEPA Filter
Plasma Spray
Powder ABC
6.25
2.86E-06
[6.25]x[2.86E-06] =
1.79E-05
Powder XYZ
10.0
2.86E-06
[10.0]x[2.86E-06] =
2.86E-05
2
Dry Filter
Flame Spray
Powder 123
0
6.20E-05
[0]x[6.20E-05] = 0
(99% effic.)
Powder XYZ
15.0
6.20E-05
[15.0]x[6.20E-05] =
9.30E-04
Twin-Wire
Wire 1
16.0
6.96E-05
[16.0]x[6.96E-05] =
1.11E-03
Total =
0.002
Image
Based on this emission level, Thermal Spraying Inc. is
					 below the Tier 1 threshold for hexavalent chromium. Therefore, no new control
					 efficiency requirements would be imposed by this ATCM because of hexavalent
					 chromium emissions. However, Thermal Spraying Inc. will still need to comply
					 with the permitting, monitoring, and recordkeeping requirements of the ATCM. In
					 addition, if the workload increased and emissions exceeded Tier 1 thresholds,
					 it would be necessary to upgrade the dry filter system or limit the usage of
					 all chromium materials to the booth that has the HEPA filter.
For nickel, the annual emissions are -
Qty. of Nickel Used
Emission Factor
Annual Emissions
Booth
Control Device
Operation
Materials Used
(lbs Ni sprayed/yr)
(lb Ni/lb Ni sprayed)
(lb Ni/yr)
1
HEPA Filter
Plasma Spray
Powder ABC
0
1.72E-05
[0]x[1.72E-05 ] =0
Powder XYZ
37.5
1.72E-05
[37.5]x[1.72E-05]
= 6.45E-04
2
Dry Filter
Flame Spray
Powder 123
9.5
1.10E-03
[9.5]x[1.10E- 03]=
(99% effic.)
1.05E-02
Powder XYZ
56.25
1.10E-03
[56.25]x[1.10E-03]
= 6.19E-02
Twin-Wire
Wire 1
4.0
6.0E-05
[4.0]x[6.0E-05]=
2.40E-04
Total =
0.073
Image
Based on this emission level, Thermal Spraying Inc. is
					 below the Tier 1 threshold for nickel. Therefore, no new control efficiency
					 requirements would be imposed by this ATCM because of nickel emissions.
					 However, Thermal Spraying Inc. will still need to comply with the permitting,
					 monitoring, and recordkeeping requirements of the ATCM. In addition, if the
					 workload increased and emissions exceeded Tier 1 thresholds, it would be
					 necessary to upgrade the dry filter system or limit the usage of all nickel
					 materials to the booth that has the HEPA filter.
Step 7: Calculate the maximum hourly emissions for nickel.
					 Powder 123 is the material that has the highest weight percentage of nickel
					 (95%). The maximum spray rate for the flame spraying gun is 10 lbs/hr. The
					 emission factor for flame spraying is 1.10E-03 lb Ni/lb Ni sprayed.
[Maximum Hourly Usage] = [Maximum Gun Spray Rate]*[Maximum
					 Wt.% Nickel]
[Maximum Hourly Usage] = [10 lbs/hr]*[95% Ni] = 9.5 lbs Ni
					 sprayed/hr
[Maximum Hourly Emissions] = [Emission Factor]*[Maximum
					 Hourly Usage]
Maximum Hourly Emissions = [1.10E-03 lb Ni/lb Ni
					 sprayed]*[9.5 lbs Ni sprayed/hr] = 0.01 lb Ni/hr
The maximum hourly emissions for nickel are 0.01 lbs Ni/hr,
					 which is well below the compliance limit of 0.1 lb Ni/hr for point sources.
					 Therefore, this thermal spraying operation complies with the maximum hourly
					 limit for nickel.
Volume Source Example:
Machine Shop Inc. conducts flame spraying with powder on
					 small parts. The parts are turned on a lathe while spraying is being performed.
					 Since the lathe is not located in a booth, the shop uses a portable local
					 exhaust fan to remove fumes from the worker's breathing area. This type of
					 operation would be considered a volume source with 0% control efficiency.
					 Listed below is information on the facility's operations:
Booth
Control
Operation
Materials
Quantity
% Total
%
Device
Used
Used
Chromium
Nickel
None
None
Flame Spray
Powder 123
20 lbs/yr
0%
95%
(uncontrolled)
Powder XYZ
5 lbs/yr
20%
75%
Image
An example calculation is provided below for Machine Shop
					 Inc.:
Step 1: Identify all thermal spraying materials that
					 contain at least 0.1% by weight of chromium (Cr), chromium compounds, nickel
					 (Ni), or nickel compounds.
The following two products contain chromium or nickel:
					 Powder 123 and Powder XYZ.
Step 2: Determine the total percentage of chromium and/or
					 nickel .
Materials Used
% Total
% Nickel
Chromium
Powder 123
0%
95%
Powder XYZ
20%
75%
Step 3: Compile the annual material usage.
Operation
Materials Used
Quantity Used
Flame Spray
Powder 123
20 lbs/yr
Powder XYZ
5 lbs/yr
Step 4: Calculate the annual usage quantities for chromium
					 and nickel.
Materials
Quantity
% Total
%
Qty. of Total
Used
Used
Chromium
Nickel
Chromium Used
Qty. of Nickel Used
Powder 123
20 lbs/yr
0%
95%
[20 lbs/yr]x[0% Cr] =
[20 lbs/yr]x[9 5% Ni] =
0 lbs Cr/yr
19.0 lbs Ni/yr
Powder XYZ
5 lbs/yr
20%
75%
[5 lbs/yr]x[20% Cr] =
[5 lbs/yr]x[75 % Ni] =
1.0 lbs Cr/yr
3.75 lbs Ni/yr
Image
Step 5: Identify the applicable emission factors.
Emission Factor -
Control
Hexavalent Chromium
Emission Factor - Nickel
Device
Operation
(lb Cr+6/lb Cr sprayed)
(lb Ni/lb Ni sprayed)
Uncontrolled
Flame Spray
6.20E-03
1.10E-01
Image
Step 6: Calculate annual emissions ([Annual Emissions] =
					 [Emission Factor]*[Annual Usage].)
For hexavalent chromium, the annual emissions are -
Qty. of Total
Chromium
Emission
Used
Factor
Annual
Control
Materials
(lbs Cr
(lb Cr+6/lb Cr
Emissions
Booth
Device
Operation
Used
sprayed/yr)
sprayed)
(lb Cr+6/yr)
None
None
Flame Spray
Powder 123
0
6.20E-03
[0]x[6.20E-03]
= 0
Powder XYZ
1.0
6.20E-03
[1.0]x[6.20E-03]
= 6.20E-03
Total =
0.006
Image
Based on this emission level, Machine Shop Inc. is
					 classified as Tier 1 for hexavalent chromium. Therefore, the thermal spraying
					 operation would need to install a new booth with a control device that met the
					 Tier 1 minimum efficiency requirement of 99%. In addition, Machine Shop Inc.
					 would need to comply with the permitting, monitoring, and recordkeeping
					 requirements of the ATCM. Machine Shop Inc. could avoid having to install a new
					 booth and control device, if they eliminated the use of chromium-containing
					 materials.
For nickel, the annual emissions are -
Qty. of
Emission
Nickels Used
Factor
Annual
Control
Materials
(lbs Ni
(lb Ni/lb Ni
Emissions
Booth
Device
Operation
Used
sprayed/yr)
sprayed)
(lb Ni/yr)
None
None
Flame Spray
Powder 123
19.0
1.10E-01
[19.0]x[1.10E-01 ]
= 2.09
Powder XYZ
3.75
1.10E-01
[3.75]x[1.10E-01]
= 4.13E-01
Total =
2.50
Image
Based on this emission level, Machine Shop Inc. is below
					 the Tier 1 threshold for nickel. Therefore, no new control efficiency
					 requirements would be imposed by this ATCM because of nickel emissions.
					 However, this ATCM requires thermal spraying operations to comply with the most
					 stringent control efficiency. Since the control efficiency requirement based on
					 hexavalent chromium is the most stringent, they must comply with the 99%
					 control efficiency.
Step 7: Calculate the maximum hourly emissions for
					 nickel.
Powder 123 is the material that has the highest weight
					 percentage of nickel (95%).
The maximum spray rate for the flame spraying gun is 10
					 lbs/hr.
The emission factor for flame spraying is 1.10E-01 lb Ni/lb
					 Ni sprayed.
[Maximum Hourly Usage] = [Maximum Gun Spray Rate]*[Maximum
					 Wt.% Nickel]
[Maximum Hourly Usage] = [10 lbs/hr]*[95 % Ni] = 9.5 lbs Ni
					 sprayed/hr
[Maximum Hourly Emissions] = [Emission Factor]*[Maximum
					 Hourly Usage]
Maximum Hourly Emissions = [1.10E-01 lb Ni/lb Ni
					 sprayed]*[9.5 lbs Ni sprayed/hr] = 1.1 lb Ni/hr
The maximum hourly emissions for nickel are 1.1 lbs Ni/hr,
					 which exceeds the compliance limit of 0.01 lb Ni/hr for volume sources.
					 Therefore, this thermal spraying operation does not comply with the maximum
					 hourly limit for nickel and it would be necessary to reduce emissions (e.g.,
					 install a control device, limit usage, etc.)