1 

CITY OF PHILADELPHIA

Department of Public Health 

Environmental Protection Division 

Air Management Services 

InterOffice Memo 

To: File 

From: Biji Pandisseril 

Date: December 18, 2014 

Subject: 8-Hour RACT Analysis for Sun Chemical - (PLID # 02052) 

Introduction: 

The Clean Air Act (CAA) requires that moderate (or worse) ozone nonattainment areas implement reasonably 

available control technology (RACT) controls on all major sources of VOC and NOx. Philadelphia County is part 

of the Philadelphia-Wilmington-Atlantic City moderate ozone nonattainment area for the 1997 8-hour ozone 

NAAQS. This document presents the findings of a RACT evaluation for the 1997 8-hour ozone standard for this 

facility. 

Company Description: 

Sun Chemical manufactures and distributes commercial printing ink in Philadelphia, Pennsylvania. Specifically, the 

manufacturing process at the Philadelphia facility produces solvent-based and water-based printing ink for the 

packaging industry, and middle distillate oil-based printing ink for the web publication industry. 

Applicability for NOx and VOC RACT: 

Sun Chemical is not a major source for Nitrogen Oxides (NOx) emission having potential NOx emissions less than 

100 tons per year, the major source threshold in Philadelphia County that is applicable to NOx RACT for the 1997 

8-hour ozone NAAQS. The facility is a major source of Volatile Organic Compounds (VOC) having potential VOC 

emissions is greater than 50 tons per year, the major source threshold in Philadelphia County that is applicable to 

VOC RACT for the 1997 8-hour ozone NAAQS. 

Process Descriptions: 

Sun Chemical VOC emission sources include Manufacturing Group 140 – Conventional Blends, Manufacturing 

Group 140 – Rotor Stator Production, Manufacturing Group 142 – Horizontal Mill Station, Manufacturing Group 

141 – Ball Mill Production, and Manufacturing Group 143 – Kady Mill Production. The facility also has fugitive 

emissions from underground tanks. 

 The Manufacturing Group 140 – Conventional Blends include 25 mixers, 3 bench-top mixers, and 2 tanks.

 The Manufacturing Group 140 – Rotor Stator Production include 5 mixers. 

 The Manufacturing Group 142 – Horizontal Mill Station include 2 mixers 

 The Manufacturing Group 141 – Ball Mill Production include 1 ball mill 

 The Manufacturing Group 143 – Kady Mill Production include 4 kady mills. 

 
 2 

RACT Analysis: 

I. Manufacturing Group 140 – Conventional Blends 

Materials processed in this area are typical of solvent-based inks. There are three processing stages involved with 

this manufacturing group: raw material addition, mixing and packaging into customer ready containers. 

Description: 

Ink is processed in the conventional blending area using standard post mixer equipped with a radial 

dispersion blade. Raw materials for each batch are manually dispensed into the mixing vessel. The vessel 

is brought to the mixer for blending. 

Drums of raw material are retrieved from the warehouse, covers are removed and the material is poured 

into the mixing vessel. Typically, the vessel is equipped with casters and is pushed / pulled into position at 

the mixer. Once homogeneous, a sample is taken to the lab for analysis. Adjustments are made to the 

batch as necessary; when the mixture is approved for quality, the mixing vessel is removed from the mixer 

and brought to the packaging area, where the ink is dispensed into shipping containers. 

The mixing unit is washed using a solvent compatible with the prior batch. The wash cycle is implemented 

to prevent color contamination between batches. 

The following were considered possible VOC controls: vessel covers; water-cooled vessel covers; condensers with 

water-cooled vessel covers; and Raw Material Dispensing – Transfer Pump. 

Evaluation of Proposed Control Systems 

1) Raw Material Dispensing – Transfer Pump 

The addition of raw materials is conducted manually. Drums of raw material are retrieved from the 

warehouse, covers are removed and the material is poured into the mixing vessel. 

One technique considered for raw material additions includes dispensing from a closed head drum by 

using a transfer pump instead of the current practice of dispensing from an open drum. 

Use of a transfer pump is technically infeasible because colored ink concentrate and solvent residues will 

cling to the inside and outside of the pump, creating potential for contamination of the product. Cleaning 

of the pump would be required, which would increase net VOC emissions. 

The following control options are technically feasible: 

(a) Vessel Covers 

The mixing operation for these manufacturing groups are characterized by short, slow speed mix 

cycles and therefore are expected to generate a relatively minor amount of VOCs. 

(b) Water Cooled Vessel Covers 

Water-cooled vessel covers for the mixing stations results in incrementally higher control efficiency. 

(c) Condenser and Water-Cooled Vessel Covers 

This technology also considered for VOC emission control technology. 

Source Control Technology Baseline 

Emission 

VOC (tpy) 

VOC 

Reduction 

(%) 

VOC 

Reduction 

(tpy) 

Total 

Annualized 

Cost 

Cost 

Effectiveness 

($/Ton) 

Blends 

production 

Vessel Cover 11.895 35.9 4.27 $164,905 38,619 

Water Cooled Cover 11.895 43.59 5.185 $348,543 67,221 

Water Cooled Cover and 

Condenser 

11.895 47.69 5.673 $560,375 98,779 

Vessel 

clingage 

Vessel Cover 2.75 100 2.75 $164,905 59,965 

Water Cooled Cover 2.75 100 2.75 $348,543 126,743 

Water Cooled Cover and 2.75 100 2.75 $560,375 203,773 
 3 

Condenser 

Clean up Vessel Cover 9.15 16.67 1.525 $164,905 108,134 

Water Cooled Cover 9.15 16.67 1.525 $348,543 228,553 

Water Cooled Cover and 

Condenser 

9.15 16.67 1.525 $560,375 367,459 

All of these technologies are determined economically unreasonable. Please see the Appendix for more details on 

the calculations. 

Conclusions and Recommendations: 

It is recommended that the 1-hour ozone RACT in the RACT Plan Approval (PA Permit Number 51-2052) dated on 

July 14, 2000 and approved by EPA as 1-hr RACT on 10/31/01 FR 54710, still be considered to represent NOx 

RACT for the 8-hour ozone standard for the Mixing -Vessel covers. 

II. Manufacturing Group 142 – Rotor Stator Production 

Description 

The materials processed in this area will be typical of solvent based ink. There are two processing stages 

involved with this manufacturing group: raw material dispensing and high speed pigment dispersion (using 

post mixers with rotor stator assemblies rather than radial dispersion blades). 

Liquid raw materials for each batch are manually dispensed into the mixing vessel. The mixing vessel is 

brought to the rotor stator mixer where dry pigment powder is added at a controlled rate. As the mixture is 

dispersed, the pigment particles are reduced to smaller particle sizes. The rotor stator assembly increases 

the temperature of the mixture because of the “work” being performed by the mixer blades. 

Once the particle size reduction cycle is complete, the vessel is removed from the mixer and is either 

packaged or further processed through a horizontal mill. 

Typically, a wash cycle for the mixer follows batch completion. 

The following were considered possible VOC controls: vessel covers; water-cooled vessel covers;condensers with 

water-cooled vessel covers; Raw Material Dispensing – Transfer Pump & Vapor Vent-Back Line on Mill Discharge 

Drum. 

Evaluation of Proposed Control Systems 

1) Raw Material Dispensing – Transfer Pump 

The addition of raw materials is conducted manually. Drums of raw material are retrieved from the 

warehouse, covers are removed and the material is poured into the mixing vessel. 

One technique considered for raw material additions includes dispensing from a closed head drum by 

using a transfer pump instead of the current practice of dispensing from an open drum. 

Use of a transfer pump is technically infeasible because colored ink concentrate and solvent residues will 

cling to the inside and outside of the pump, creating potential for contamination of the product. Cleaning 

of the pump would be required, which would increase net VOC emissions. 

2) Vapor Vent-Back Line on Mill Discharge Drum 

A vapor vent-back line from the discharge drum back to the feed vessel appears technically infeasible; the 

productivity will decrease as a result of the increased set-up time for each batch. This technology is 

technically infeasible. 
 4 

The following control options are technically feasible: 

(a) Vessel Covers 

The mixing operation for these manufacturing groups are characterized by short, slow speed mix 

cycles and therefore are expected to generate a relatively minor amount of VOCs. 

(b) Water Cooled Vessel Covers 

Water-cooled vessel covers for the mixing stations results in incrementally higher control efficiency. 

(c) Condenser and Water-Cooled Vessel Covers 

This technology also considered for VOC emission control technology. 

Source Control Technology Baseline 

Emission 

NOx (tpy) 

NOx 

Reduction 

(%) 

NOx 

Reduction 

(tpy) 

Total 

Annualized 

Cost 

Cost 

Effectiveness 

($/Ton) 

Blends 

production 

Vessel Cover (1 hr RACT) 20.68 77.8 16.09 $10,591 658 

Milling 

(vapor 

vent back 

line) 

Vessel Cover 0.33 6.8 0.0225 $10,591 470,711 

Vessel 

Clingage 

Vessel Cover 0.081 100 0.081 $10,591 130,753 

Clean up Vessel Cover 0.27 16.67 0.045 $10,591 235,356 

All of these technologies are determined economically unreasonable. Please see the Appendix for more details on 

the calculations. 

Conclusions and Recommendations: 

It is recommended that the 1-hour ozone RACT in the RACT Plan Approval (PA Permit Number 51-2052) dated on 

July 14, 2000 and approved by EPA as 1-hr RACT on 10/31/01 FR 54710, still be considered to represent NOx 

RACT for the 8-hour ozone standard for the Mixing -Vessel covers. 

III. Manufacturing Group 142-Horizontal Mill Station 

Description 

There are three processing stages involved with this manufacturing group: raw material dispensing, high 

speed dispersion, and milling. The raw materials processed in this area will be typical of solvent-based 

inks. 

Generally, the batch will be processed at the rotor stator mixer or conventional post mixer. Liquid raw 

materials are weighed into a mixing vessel and the vessel is locked in position on the mixer. Pigment 

powder is added at a controlled rate and the mixture is dispersed until the pigment particle sizes are 

reduced to a degree acceptable by our quality control standards. 

Upon completion of this cycle, the vessel discharge is connected by hose to the horizontal mill inlet. The 

ink is processed through the mill to further reduce the pigment particle size. The mill discharges into a 

clean drum which, when full, is sealed and brought to the warehouse for storage. 

A wash cycle using a solvent compatible with the prior batch is implemented for the mixer following 

batch completion. The wash cycle is implemented to prevent color contamination between batches. 

The following were considered possible VOC controls: Raw Material Dispensing – Transfer Pump; vessel covers; 

water-cooled vessel covers; Condenser and Water-Cooled Vessel Covers; Vapor Vent-Back Line on Mill Discharge 

Drum control technologies are identified;. 
 5 

Evaluation of Proposed Control Systems 

1) Raw Material Dispensing – Transfer Pump 

Liquid raw materials for each batch are manually dispensed into the mixing vessel. The mixing vessel is 

brought to the mixer where dry pigment powder is added at a controlled rate. As the mixture is dispersed, 

the pigment particles are reduced to smaller particle sizes. The nature of the dispersion blade is such that 

heat generation is expected to occur. 

One technique considered for raw material additions includes dispensing from a closed head drum by 

using a transfer pump instead of the current practice of dispensing from an open drum. 

Use of a transfer pump is technically infeasible because colored ink concentrate and solvent residues will 

cling to the inside and outside of the pump, creating potential for contamination of the product. Cleaning 

of the pump would be required, which would increase net VOC emissions. 

2) Vapor Vent-Back Line on Mill Discharge Drum 

A vapor vent-back line from the discharge drum back to the feed vessel appears technically infeasible; the 

productivity will decrease as a result of the increased set-up time for each batch. This technology is 

technically infeasible. 

The following control options are technically feasible: 

 (a) Vessel Covers 

The permanently mounted non-cooled vessel covers are expected to reduce the emissions by about one 

third from the uncontrolled conditions. Application feasibility will be affected to the extent that these 

vessel covers will hinder the addition of pigment to the batch. A chute or similar loading device would 

need to be provided to accommodate pigment additions. The mixing tanks are required to have covers 

as required by 1-hour ozone RACT determination. The facility will continue to use cover for the 

mixing tanks to meet the 8-hour ozone RACT determination. 

 

(b) Water-Cooled Vessel Covers 

Water-cooled vessel covers represent a more aggressive control measure against VOC emissions. 

 

(c) Condenser and Water-Cooled Vessel Covers 

This technology also considered for VOC emission control technology. 

Source Control Technology Baseline 

Emission 

NOx (tpy) 

NOx 

Reduction 

(%) 

NOx 

Reduction 

(tpy) 

Total 

Annualized 

Cost 

Cost 

Effectiveness 

($/Ton) 

Blends 

production 

Vessel Cover 2.21 35.29 0.78 $13,951 17,886 

Water Cooled Cover 2.21 50.88 1.125 $27,754 24,670 

Water Cooled Cover 

and Condenser 

2.21 50.88 1.125 $44,673 39,709 

Vessel clingage Vessel Cover 0.117 100 0.117 $13,951 119,239 

Water Cooled Cover 0.117 100 0.117 $27,754 237,217 

Water Cooled Cover 

and Condenser 

0.117 100 0.117 $44,673 381,821 

Milling (vapor 

vent back line) 

Vessel Cover 1.43 93.18 1.333 $13,951 10,489 

Water Cooled Cover 1.43 93.18 1.333 $27,754 20,868 

Water Cooled Cover 

and Condenser 

1.43 93.18 1.333 $44,673 33,589 

Clean up Vessel Cover 0.39 83.33 0.325 $13,951 42,926 

Water Cooled Cover 0.39 83.33 0.325 $27,754 85,397 

Water Cooled Cover 

and Condenser 

0.39 83.33 0.325 $44,673 137,455 
 6 

All of these technologies are determined economically unreasonable. Please see the Appendix for more details on 

the calculations. 

Conclusions and Recommendations: 

It is recommended that the 1-hour ozone RACT in the RACT Plan Approval (PA Permit Number 51-2052) dated on 

July 14, 2000 and approved by EPA as 1-hr RACT on 10/31/01 FR 54710, still be considered to represent NOx 

RACT for the 8-hour ozone standard for the Mixing -Vessel covers. 

IV. Manufacturing Group 141 – Ball Mill Production 

Description 

There are three stages involved with this manufacturing group: raw material additions, milling, and 

finished product dispensing into drums ready for warehousing. 

The ball mill is a sealed cylindrical container which is rotated in its horizontal axis. The function of the 

ball mill is similar to the horizontal mill previously discussed - to disperse pigment particles. The liquid 

raw material and dry pigment powder are added via a chute mechanism. Once raw material additions are 

complete, the ball mill is sealed and the milling cycle is initiated. Upon completion of the milling cycle, 

the ink product is discharged into drum containers via a discharge pipe. 

The following were considered possible VOC controls for Raw Material Dispensing – Transfer Pump; for 

Dispensing of Finished Ink. 

Evaluation of Proposed Control Systems 

1) Raw Material Dispensing – Transfer Pump 

One technique considered for raw material additions includes dispensing from a closed head drum by 

using a transfer pump instead of the current practice of dispensing from an open drum 

Use of a transfer pump is technically infeasible because colored ink concentrate and solvent residues will 

cling to the inside and outside of the pump, creating potential for contamination of the product. Cleaning 

of the pump would be required, which would increase net VOC emissions. 

2) Dispensing of Finished Ink 

At completion of the mill cycle, the finished product is dispensed via a constricted opening into a clean 

drum. The drum is immediately sealed and brought to the warehouse for storage or shipping. 

Control equipment was not evaluated for this operation because the facility believes that this operation is 

currently conducted in its simplest form and no alternative technique nor control equipment could be 

applied. Therefore control options are technically infeasible. 

Conclusions and Recommendations: 

It is recommended that there is no identified control technology for this source. 

V. Manufacturing Group 143 – Kady Mill Production 

Description 

The Kady Mill operation consists of three stages: raw material addition, high-speed dispersion, and 

finished product dispensing into drums ready for warehousing. 

The Kady Mill is a covered mixing tank with a bottom mounted rotor stator dispersion assembly. The 

mixing tank is water-jacketed for cooling during the high speed dispersion cycle. The liquid raw material 

is added via a chute mechanism. Once raw material additions are complete, the milling cycle is initiated. 
 7 

Upon completion of the milling cycle, the ink product is discharged into drum containers via a discharge 

pipe. 

The following were considered possible VOC controls: Raw Material Dispensing – Transfer Pump; vessel 

covers; water-cooled vessel covers;Condenser; and Dispensing of Finished Ink control technologies are 

identified 

Evaluation of Control Systems 

The material handling techniques are similar to the Evaluation of Proposal Control Systems for Ball Mill 

equipment. 

1) Raw Material Dispensing – Transfer Pump 

One technique considered for raw material additions includes dispensing from a closed head drum by 

using a transfer pump instead of the current practice of dispensing from an open drum. 

Use of a transfer pump is technically infeasible because colored ink concentrate and solvent residues will 

cling to the inside and outside of the pump, creating potential for contamination of the product. Cleaning 

of the pump would be required, which would increase net VOC emissions. 

2) Dispensing of Finished Ink 

At completion of the mill cycle, the finished product will be dispensed via a constricted opening into a 

clean drum. The drum is immediately sealed and brought to the warehouse for storage or shipping. 

Control equipment was not evaluated for this operation because the facility believes that this operation is 

currently conducted in its simplest form and no alternative technique nor control equipment could be 

applied without generating additional emissions from wash-up solvents required to clean discharge units. 

The following options are considered technically feasible: 

 (a) Vessel Covers 

A vessel cover is standard for this equipment. Therefore, an evaluation of this option has not been 

included in this report. The mixing tanks are required to have covers as required by 1-hour ozone 

RACT determination. The facility will continue to use cover for the mixing tanks to meet the 8-

hour ozone RACT determination. 

(b) Water Cooled Covers 

Water-cooled covers appear technically feasible. Increased condensation rates are anticipated with the 

use of water cooled vessel covers. . 

(c) Condenser and Water-Cooled Vessel Covers 

Replacing existing covers with water-cooled covers and a condenser is expected to increase VOC 

removal efficiency. 

Source Control Technology Baseline 

Emission 

NOx (tpy) 

NOx 

Reduction 

(%) 

NOx 

Reduction 

(tpy) 

Total 

Annualized 

Cost 

Cost 

Effectiveness 

($/Ton) 

Candy 

Mills 

Production 

Vessel Cover 2.09 100 2.09 $56,992 27,269 

Water Cooled Cover 2.09 98.9 2.07 $56,992 27,532 

Water Cooled Cover and 

Condenser 

2.09 98.2 2.05 $56,992 27,801 

Vessel 

clingage 

Vessel Cover 1.4 100 1.4 $111,316 79,511 

Water Cooled Cover 1.4 100 1.4 $111,316 79,511 

Water Cooled Cover and 

Condenser 

1.4 100 1.4 $111,316 79,511 
 8 

All of these technologies are determined economically unreasonable. Please see the Appendix for more details on 

the calculations. 

Conclusions and Recommendations: 

It is recommended that the 1-hour ozone RACT in the RACT Plan Approval (PA Permit Number 51-2052) dated on 

July 14, 2000 and approved by EPA as 1-hr RACT on 10/31/01 FR 54710, still be considered to represent NOx 

RACT for the 8-hour ozone standard for the Mixing -Vessel covers. 

1/9/15

Edward Wiener, Chief of Source Registration Date 
 9 

Emission Calculations a Emission Factors and production rates were developed for the original 1999 VOC RACT Study. The total production rate was reduced 

manufacturing groups. Emissions factors were developed from EPA emission factors using the Emission Master Program, taken from a North American Printing Ink Manufacturer’s Association (NAPIM) and an internal material balance investigation approved by AMS. 

Uncontrolled

Process

Maximum

Production

(lbs/yr)

Estimated

Batches

VOC

Uncontrolled

(lbs)

Emission

Factor a

VOC Controlled

(lbs)

Emission

Factor a

Blends Production         ‐ 6,100,000 0.0039 lb VOC/lb ink processed 23,790 0.0025 15,006 0.0022 

Vessel Clingage ‐ 15,250 0.3600 lb VOC/ batch 5,490 0.3600 5,490 0.3600 

Clean Up ‐ 15,250 1.2 lb VOC/ batch 18,300 1.0 15,250 1.0 

Vessels In Transit         ‐ 6,100,000 0.0001 lb VOC/lb ink processed 610 ‐ ‐                 

‐ 

Blends Production            ‐ 450,000 0.0919 lb VOC/lb ink processed 41,355 0.0204 9,171 ‐ 

Milling (Vapor Vent Back Line)            ‐ 150,000 0.0044 lb VOC/lb ink processed 660 0.0041 615 ‐ 

Vessel Clingage ‐ 450 0.3600 lb VOC/ batch 162 0.3600 162 ‐ 

Clean Up ‐ 450 1.2 lb VOC/ batch 540 1.0 450 ‐ 

Vessels In Transit            ‐ 450,000 0.0003 lb VOC/lb ink processed 135 ‐ ‐ ‐ 

Blends Production            ‐ 650,000 0.0068 lb VOC/lb ink processed 4,420 0.0044 2,860 0.0033 

Milling (Vapor Vent Back Line)            ‐ 650,000 0.0044 lb VOC/lb ink processed 2,860 0.0041 2,665 0.0041 

Vessel Clingage ‐ 650 0.3600 lb VOC/ batch 234 0.3600 234 0.3600 

Clean Up ‐ 650 1.2 lb VOC/ batch 780 1.0 650 1.0 

Vessels In Transit            ‐ 650,000 0.0002 lb VOC/lb ink processed 130                   ‐ ‐ ‐ 

141 Ball Mill Ball Mills Production            ‐ 650,000 0.0003 lb VOC/lb ink processed 221 0.0003 221 0.0003 

Kady Mills Production         ‐ 8,000,000 0.0005 lb VOC/lb ink processed 4,176 0.0005 4,176 0.0005 

Vessel Clingage ‐ 2,667 1.1 lb VOC/ batch 2,800 1.1 2,800 1.1 

Total (lbs/yr) 16,650,000 106,663 59,750 

Total (tons/yr) 8,325 53 30 

Process Description Production Rates

Emission Factor Units

Uncontrolled

Emission Factor a

143 Kady Mills

Manufacturing Group

140140142

Covers Water Coole

Conventional

Blending

Rotor Stator

Horizontal

Mills

Process

Maximum

Production

(lbs/yr)

Estimated

Batches

Uncontrolled

Emission Factor a Emission Factor Units VOC Uncontrol

(lbs)

Underground Storage Tanks 7,013,618 ‐ 0.00024 lb VOC/lb ink processed 1,

Total (tons/yr) 3,507 

Fugitives

Non‐process Related

Fugitive Emissions
 10 

2014 Cost Summary a Cost estimates were developed for the original 1999 VOC RACT Study and adjusted to 2014 dollar values. The annualized capital cost includes the 

installation, mulitplied by the number of units in each manufacturing group, annualized over five years. 

b For the original RACT study, a time study was completed for each manufacturing group to determine additional time spent to complete each batch an

addition of pollution controls. The study also determined additional costs from cleaning materials and cost of additional water use due to the addition otime required was converted into labor costs. The total added costs were multiplied by batches per year to determine annual added costs due to pollutio

c Consumer Price Index (CPI) was obtained from Bureau of Labor Statistics 2000 and 2014 Detailed Reports, from Table 1. Consumer Price Index for 

U), unadjusted annual average for expenditure category is "All items" and 1982-84=100. 

Control

Annualized

Capital Cost a

Added

Overtime b

Added

Operatin

Cost b

Mixer Covers 16,456            ‐ 123,879 

Water Cooled Covers 27,716 139,364 156,8Water Cooled Covers and Condensers 42,599 154,848 313,7Vessels In Transit 393               ‐ 30,969                 

Mixer Covers 4,549                 ‐ 4,778 

Water Cooled Covers 5,476 5,309 6,3

Water Cooled Covers and Condensers 7,161 5,839 12,2

Vessels In Transit 168                 ‐ 1,061                 

Vapor Vent Back Line on Mill Discharge Drum 2,949 4,601             

1,0

Mixer Covers 4,549                 ‐ 5,751 

Water Cooled Covers 5,476 6,902 11,6

Water Cooled Covers and Condensers 7,161 6,902 23,3

Vapor Vent Back 2,949 4,601             

1,0

Vessels In Transit 84                 ‐ 1,150                 

141 Ball Mill None                    ‐ ‐                     ‐                 

Water Cooled Covers (and Venting Flame Arrestor) 3,229 14,157 35,8

Water Cooled Covers and Condensers (and Venting Flame Arrestor) 3,791 28,316 71,7

Vapor Vent Back Line 7,020                 ‐                       ‐                   

Manufacturing Group

140

Conventional

Blending

140 Rotor Stator142 Horizontal Mill143 Kady Mill

Non‐process Related Fugitive

Emissions ‐ Tanks