p.1 

OAR Box 1313 

Prepped by LaTeia Shed 

Document Number: 

43) ll-B-17 

Docket Number: 

A-88-02 

Printed 6/12/2008 9:03:29 AM Sheet 43 of 99 
VIRI(§) 

PYZ_ 

JI-B-/7 

_ -», *••* *« i •* 1 MIDWESTRESEAffCFl INSTITUTE 

\ . . . , Suite 350 

1

 '* *1 'j '.*. .: '-J '.is*** 401 Harrison Oaks Boulevard 

Cary. N.C. 27513 

Date: December 19, 1986 

Subject: Final Model Plant Parameters, Baseline Controls, and Regulatory 

Alternatives for Chromium Electroplating and Chromic Acid 

Anodizing Operations 

Chromium Electroplating NESHAP 

EPA Contract 68-02-3817; ESED Project 85/Q2STT. 

MRI Project 7717-K

 n ' ' 

From: Randy Strai t/JTo: Al Vervaert 

ESED/ISB/SSS (MD-13) 

U. S. Environmental Protection Agency 

Research Triangle Park, N.C. 27711 

(919) 541-5601 

I. Introduction 

This memorandum provides parameters for model plants that are 

representative of existing and new chromium electroplating and chromic 

acid anodizing facilities. It also presents information about baseline 

controls for existing facilities and identifies several potential 

regulatory alternatives. 

II. Model Plants 

Eight model plants were developed to characterize chromium 

electroplating and chromic acid anodizing operations that are capable of 

plating or anodizing a wide variety of products including those upon which 

the economic analysis of regulatory alternatives will be based. Three 

model plants each (small, medium, and large) for hard and decorative 

plating operations and two model plants (small and large) for anodizing 

operations were developed to represent adequately any plant for the 

purpose of regulatory impact analysis. Process and operating condition 

parameters were given primary consideration for determining the size and 

number of model plants. These parameters include ampere-hours used per 

year, chromic acid consumption per year, operating time, total tank 

capacity, and total number of tanks. Values for these parameters were 

obtained from Phase I Section 114 information requests and plant visit and 

telephone contact reports. The range of values for each parameter was 

divided into the size classifications, and typical values for each 

parameter were then used to define a model facility for each size 

classification. The ranges for these parameter values are shown in 

Table 1. The values used to define production, operating time, process, 

capture system, control technique, and stack discharge parameters for each 

model plant are presented in Tables 2, 3, and 4. 

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P.3 

The American National Standards Institute guidelines for capture 

systems yere used to determine ventilation rates for the capture 

systems. Table 5 presents the ventilation rates for each of the six 

model tanks used in the development of the model plants. Table 6 presents 

the number, size, and total ventilation rates of the tanks vented to a 

common control device for each model plant. For five of the model plants, 

all tanks are vented to a common control device. For the medium size 

decorative plating model plant, each of the three tanks is vented to a 

separate control device. For the large decorative plating model plant, 

one of the five 12-foot tanks is vented to one control device while two of 

the 12-foot tanks each are vented to two separate control devices. For 

the large hard chromium plating model plant, the two 4-foot, five 12-foot, 

and three 25-foot tanks are vented to three separate control devices. It 

was assumed that different combinations of tanks would be vented to 

separate control devices because the plant would be able to continue to 

operate some of its plating operations when one control device or plating 

operation was down for repairs. For each model plant, the control device 

inlet gas flow rates presented in Tables 2, 3, and 4 are based on the 

total ventilation rates for the combinations of model tanks presented in 

Table 7. In some cases, total ventilation rates were rounded to the gas 

flow rates for which factory-assembled units are available. 

III. Baseline Emissions and Controls 

Baseline controls for chromium plating and chromic acid anodizing 

operations will not be based on existing State regulations as is generally 

the case because only a few States have air pollution regulations specific 

for chromium. Generally, the State regulations are not expressed in terms 

of an emission limit; they require plants either to use best available 

control technology or to achieve an ambient concentration expressed as a 

percentage of the threshold limit value for chromium. Therefore, the 

baseline will be determined from information about control techniques 

currently used by existing operations and data obtained during the 

emission test program. 

The control techniques information was obtained from telephone 

contact and plant visit reports and Phase I Section 114 information 

requests for 107 decorative and 89 hard chromium plating operations and 

17 chromic acid anodizing operations. A summary of these data is 

presented in Table 7. 

The information presented in Table 7 shows that about 11 percent of 

the decorative chromium plating operations are uncontrolled, 38 percent 

are controlled by fume suppressants, 38 percent are controlled by fume 

suppressants in conjunction with a scrubber or mist eliminator, and 

12 percent are controlled by scrubbers. Therefore, baseline conditions 

for decorative plating operations should include an uncontrolled level and 

three levels of control: one level based on the use of fume suppressants, 

one level based on the use of fume suppressants used in conjunction with a 

control device, and one level based on the use of scrubbers. The three 

levels of control may be reduced to one or two levels of control if 

emission test results show that the control efficiency of fume 

suppressants is similar to those for scrubbers. 

5L 
P.4 

Baseline data obtained for hard chromium plating operations indicate 

that about 22 percent are uncontrolled, 9 percent are controlled by mist 

eliminators, and 68 percent are controlled by scrubbers. Based on the 

data presented in Table 7, baseline conditions for hard plating operations 

should include an uncontrolled level and two levels of control: one level 

based on the use of mist eliminators and one level based on the use of 

scrubbers. 

Four of the 89 hard chromium plating shops contacted stated that 

they use a fume suppressant as a control technique. However, fume 

suppressants typically are not used to control misting from conventional 

hard chromium plating operations because they cause pitting on hard 

chromium plated surfaces. Therefore, fume suppressants will not be 

considered as a control technique for the baseline. 

Baseline data obtained for chromium anodizing operations indicate 

that about 59 percent are uncontrolled, 29 percent are controlled by fume 

suppressants, and 12 percent are controlled by scrubbers. Therefore, 

baseline conditions should include an uncontrolled level and two levels of 

control: one level based on the use of fume suppressants and one level 

based on the use of scrubbers. 

Uncontrolled emission data for six hard chromium plating operations 

are presented in Table 8. Emissions tests for determining uncontrolled 

emissions from decorative chromium plating and chromic acid anodizing 

operations have not been completed. Uncontrolled emission levels for the 

baseline condition will be based on these data. Controlled emission 

levels for the baseline condition will be based on control device 

performance data obtained from the emission test program. 

Nearly all of the plants use some type of capture system to comply 

with Occupational Safety and Health Administration regulations that limit 

chromium concentrations inside the plant to a maximum acceptable 

concentration of 0.1 milligram per cubic meter (4.2x10" grains per cubic 

foot). Therefore, emission capture systems will be considered as a part 

of the baseline for all plants including those with no control devices. 

Facilities that use.scrubbers to control chromium emissions 

typically do not incur wastewater treatment costs associated with the use 

of the control device. Hard chromium plating facilities typically avoid 

wastewater treatment costs by continuously recirculating scrubber 

liquor. The scrubber liquor is recirculated from several hours to several 

days and then is drained to the plating bath to make up for plating 

solution evaporation losses. The scrubber is recharged with clean water 

after being drained. This practice also minimizes water consumption and 

allows for the recovery of chromic acid. Decorative chromium plating 

facilities that use scrubbers typically do not use scrubber liquor to make 

up for plating solution evaporation losses because fume suppressants are 

used to minimize evaporation losses. However, many facilities avoid 

wastewater treatment costs and minimize water consumption by recirculating 

through the scrubber the rinse water from the rinse tanks that follow the 

chromium plating tank. 

3 
P.5 

Some hard and most decorative plating facilities install waste 

treatment systems to treat wastes from plating baths. Some of these 

facilities do drain the scrubber liquor to a waste treatment system. 

However, the cost of treating scrubber liquor relative to the total cost 

of waste treatment associated with plating operations is low. 

Facilities that use mist eliminators also avoid waste treatment 

costs associated with the use of the control device by draining the wash 

down water to the plating tank to make up for plating solution evaporation' 

losses. 

IV. Regulatory Alternatives 

Regulatory alternatives will be developed to evaluate the 

environmental, cost, and economic impacts of various levels of chromium 

emission reduction. The alternative based on baseline controls will 

represent the "no-action" alternative. Another regulatory alternative 

will represent the most stringent level of control based on the use of the 

best emission capture and control system on all model plants regardless of 

size. For example, this alternative may be based on the use of a 

packed-bed scrubber by captive and job shops that perform hard chromium 

plating and the use of a fume suppressant and a packed-bed scrubber by all 

captive and job shops that perform decorative chromium plating or chromic 

acid anodizing. Additional regulatory alternatives will be developed to 

represent intermediate levels of control for either a category or a 

subcategory of plant sizes. For example, one alternative for small job 

shops may be based on the use of mist eliminators instead of scrubbers 

because the cost of scrubbers may have a significant cost and economic 

impact on this subcategory. 

Regulatory alternatives based on the use of scrubbers and/or mist 

eliminators will not increase wastewater treatment costs for this source 

category. It is common practice for chromium plating facilities to avoid 

wastewater treatment costs by recirculating scrubber liquor and draining 

the liquor to a chromium plating or rinse tank or by draining mist 

eliminator washdown water to a chromium plating tank. 

V. References 

1. American National Standard Practices for Ventilation and Operation of 

Open-Surface Tanks. ANSI 29.1-1977. American National Standards 

Institute, Inc., New York, New York. 1977. 

2. Memorandum from R. Strait, MRI, to A. Vervaert, EPA/ISB. July 18, 

1986. Trip report for OMITM International Corporation, Warren, 

Michigan, on January 7, 1986. 

3. U.S. Department of Labor. Code of Federal Regulations. 

29 CFR 1910.1000. Washington, D.C. July 1, 1986, p. 659. 

t 
P.6 

TABLE 1. CRITERIA FOR DETERMINING MODEL PLANT SIZES FOR 

DECORATIVE AND HARD PLATING AND CHROMIC ACID ANODIZING OPERATIONS 

Operation/parameter 

Decorative plating 

Ampere-hours used 

per year 

Chromic acid consumption, kg/yr (lb/yr) 

Operating time, 

hours/year 

Total tank capacity, 

a (gal) 

No. of tanks 

Hard plating 

Ampere-hours used 

per year 

Chromic acid consumption, kg/yr (lb/yr) 

Operating time, 

hours/year 

Total tank capacity, 

a (gal) 

No. of tanks 

Anodizing3 

Chromic acid consumption 

kg/yr (lb/yr) 

Operating time, 

hours/year 

Total tank capacity, 

a (gal) 

No. of tanks 

Small 

<15,000,000 

<4,540 

(<10,000) 

<2,000 

<13,250 

(<3,500) 

1-2 

<50,000,000 

<4,540 

(<10,000) 

<2,000 

<18,930 

(<5,000) 

1-3 

<4,540 

(<10,000) 

<2,000 

<37,850 

(<10,000) 

1 

Plant size 

Medium 

15,000,000 

-50,000,000 

4,540-11,340 

(10,000-25,000) 

2,000-6,000 

13,250-37,850 

(3,500-10,000) 

3-4 

50,000,000 

-20,000,000 

4,540-11,340 

(10,000-25,000) 

2,000-6,000 

18,930-37,850 

(5,000-10,000) 

4-9 

Large 

>50,000,000 

>11,340 

(>25,000) 

>6,000 

>37,850 

(>10,000) 

>5 

>200,000,000 

-758,000,000 

>11,340 

(>25,000) 

>6,000 

>37,850 

(>10,000) 

>10 

>4,540 

(>10,000) 

>6,000 

>37,850 

(>10,000) 

>2 

aChromium anodizing is performed by regulating the voltage rather than the 

current applied to the bath. Therefore, ampere-hours used per year was 

not considered as a process parameter for determining model plant 

sizes. 

<5 
TABLE 2. 

Parameters 

MODEL PLANT PARAMETERS FOR DECORATIVE CHROMIUM ELECTROPLATING OPERATIONS* 

Plant size 

Small Medium Large 

A. Production rate 

Total ampere-hours per year 

Time electrodes are energized, % 

Chromic acid usage, kg/yr (lb/yr) 

B. Operating time 

Hours/day 

Days/week 

Weeks/year 

Hours/year 

C. Process 

Number of tanks 

Tank dimensions, (1, w, d), m (ft) 

Total tank capacity, a (ga])b

 2 

Total tank surface area, m (ft ) 

Chromic acid concentration, g/a (oz/gal) 

Catalyst 

Catalyst concentration, g/a (oz/gal) 

Temperature of plating solution, °C (°F) 

Operating voltage, V 

Operating current, amperes 

D. Emission capture system 

Type of hood 

Ventilation rate, m /min (ft3/min)c 

6,400,000 

80 

1,100 (2,400) 

8 

5 

50 

2,000 

38,400,000 

80 

9,100 (20,000) 

16 

5 

50 

4,000 

1 3 

3.6, 1.1, 1.8 3 (? 3.6, 1.1, 1.8 

(12.0, 3.5, 6.0) (12.0, 3.5, 6.0) 

6,550 (1,730) 

3.9 (42) 

260 (35) 

Fluoride 

1 (0.15) 

38-46 (100-115) 

7.5 

4,000 

Double-sided 

lateral 

297 (10,500) 

19,650 (5,190) 

12 (126) 

250 (33) 

Fluoride 

2 (0.33) 

38-46 (100-115) 

6 

4,000 

Double-sided 

1ateral 

3 & 297 (10,500) 

150,000,000 

80 

81,600 (180,000) 

24 

5 

52 

6,240 

5 

@ 3.6, 1.8, 2.7 

(12.0, 6.0, 9.0) 

86,650 (22,890) 

33 (360) 

300 (40) 

Sulfuric acid 

2 (0.22) 

38-46 (100-115) 

16 

6,000 

Push-pull 

255 (9,000) 

2 @ 510 (18,000) 

2 <? 510 (18,000) 

(continued) 

^ 
TABLE 2. (continued) 

Parameters 

E. Control technique" 

1. Chemical fume suppressant usage, kg/yr 

(lb/yr) 

2. Control device 

Number of control devices 

Inlet gas flow rate, m /min (ft /min)e 

Inlet gas temperature, °C (°F) 

Inlet gas moisture, % 

a. Single packed-bed scrubber 

A P, kPa (in. w.c.) 

Liquid-to-gas ratio, a/1,000 m 

(gal/1,000 ft ) 

b. Double packed-bed scrubber 

A P, kPa (in. w.c.) 

Liquid-to-gas ratio, a/1,000 m 

(gal/1,000 ft ) 

c. Chevron-blade mist eliminator with 

Small 

4.5 (10) 

1 

340 (12,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75 (3) 

800 (6) 

0.19 (0.75) 

Plant size 

Medium 

2.3 (50) 

3 

3 @ 340 (12,000) 

27 (80) 

2 

0.5 (2) 

300 (3) 

0.75(3) 

800 (6) 

0.19 (0.75) 

Large 

45 (100) 

3 

283 (10,000) 

2 @ 510 (18,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75(3) 

800 (6) 

0.19 (0.75) 

single set of blades, 

AP, kPa (in. w.c.) 

d. Chevron-blade mist eliminator with 0.5 (2) 0.5 (2) 0.5 (2) 

double set of blades, 

AP, kPa (in. w.c.) 

e. Mesh-pad mist eliminator AP, 0.25 (1) 0.25 (1) 0.25 (1) 

kPa (in. w.c.) 

(continued) 

^ 
TABLE 2. (continued) 

Parameters Small 

Plant size 

Medium Large 

F. Stack 

Number of stacks 

Height, m (ft)1" 

Diameter, m (ft) 

2 (? 10.4 (34) 

Temperature, °C (°F) 

Moisture, % 

Gas flow rate, m /min (ft /min) 

Gas velocity, m/min (ft/min) 

1 

9.1 (30) 

0.7 (2.3) 

27 (80) 

2 

340 (12,000) 

914 (3,000) 

9.1 (30) 

0.7 (2.3) 

27 (80) 

2 

§ 340 (12,000) 

914 (3,000) 

9.1 (30) 

7.9 (26) 

27 (80) 

2 

283 (10,000) 

§ 510 (18,000) 

Parameter values for the small, medium, and large plant sizes are based on information obtained from 

.eight, four, and five plants, respectively. 

DTank freeboard space=6 Inches. 

cFor the medium size model plant, the three tanks are vented to three separate control devices. For the 

large model plant, the fi^e tanks are vested to three separate control devices. One tank with a 

ventilation rate of 255 m /min (9,000 ft /min) is vented tg one control device and two pairs of tanks, 

each pair with a ventilation rate of 510 m /min (18,000 ft /min), are vented to two separate control 

devices. 

Model plant parameters are presented for all control techniques. A fume suppressant alone or in 

combination with a scrubber or mist eliminator may be used at any given plant. 

^Ventilation rates were rounded to the gas flow rates for which factory-assembled units are available. 

Stack height is the distance from ground level to the point of discharge. 

oo 

**. CO 
TABLE 3. MODEL PLANT PARAMETERS FOR HARD CHROMIUM ELECTROPLATING OPERATIONS3 

Parameters Small 

Plant size 

Medium Large 

A. Production rate 

Total ampere-hours per year 

Time electrodes are energized, % 

Chromic acid usage, kg/yr (lb/yr) 

B. Operating time 

Hours/day 

Days/week 

Weeks/year 

Hours/year 

C. Process 

Number of tanks 

Tank dimensions, (1, w, d), m (ft) 

Total tank capacity, a (gap 

Total tank surface area, m (ft ) 

Chromic acid concentration, g/a (oz/gal) 

Catalyst 

Catalyst concentration, g/a (oz/gal) 

Temperature of plating solution, °C (°F) 

Operating voltage, V 

Operating current, amperes 

25,600,000 

80 

1,800 (5,000) 

8 

5 

50 

2,000 

3.6, 1.2, 1.8 

(12.0, 4.0, 6.0) 

7.6, 0.9, 1.8 

(25.0, 3.0, 6.0) 

19,150 (5,060) 

11 (123) 

250 (33) 

Sulfuric acid 

2 (0.33) 

49-65 (120-150) 

6 

8,000 

122,800,000 

80 

9,300 (20,500) 

16 

5 

48 

3,840 

1.2, 1.2, 3.0 

(4.0, 4.0, 10.0) 

(3 3.6, 1.2, 1.8 

(12.0, 4.0, 6.0) 

7.6, 0.9, 1.8 

(25.0, 3.0, 6.0) 

32,520 (8,110) 

19 (187) 

250 (33) 

Sulfuric acid 

2 (0.33) 

49-65 (120-150) 

7 

10,000 

806,400,000 

80 

13,600 (50,000) 

24 

7 

50 

8,400 

10 


 1.2, 1.2, 3.0 

(4.0, 4.0, 10.0) 

@ 3.6, 1.2, 1.8 

(12.0, 4.0, 6.0) 

@ 7.6, 0.9, 1.8 

(25.0, 3.0, 6.0) 

81,010 (21,400) 

46 (497) 

250 (33) 

Sulfuric acid 

2 (0.33) 

49-65 (120-150) 

12 

12,000 

(continued) 

^ Tl 

o 
TABLE 3. (continued) 

Plant size 

Parameters Small Medium Large 

D. Emission capture system 

Type of hood 

Ventilation rate, m /min 

(ft /min)c 

E. Control technique 

Control device 

Number of control devi< 

Push-pull, 

double-sided 

lateral 

701 (24,750) 

iges 

Inlet gas flow rate, m /m1n (ft /min)e 

Inlet gas temperature, °C (°F) 

Inlet gas moisture, % 

1. Single packed-bed scrubber, 

AP, kPa (in. w.c.) 

Liquid-to-gas ratio, a/1,000 m 

(gal/1,000 f t ) 

2. Double packed-bed scrubber, 

AP, kPa (in. w.c.) 

Liquid-to-gas ratio, a/1,000 m 

(gal/1,000 f t ) 

3. Chevron-blade mist eliminator with 

single set of blades AP, kPa (in. w.c.) 

Push-pull, 

double-sided 

lateral 

871 (30,750) 

736 (26,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75 (3) 

800 (6) 

0.19 (0.75) 

991 

0. 

(35,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75 (3) 

800 (6) 

19 (0.75) 

Push-pull, 

double-sided 

lateral 

2 @ 113 (4,000) 

5 @ 850 (30,000) 

3 @ 1,610 (56,250) 

113 (4,000) 

850 (30,000) 

1,700 (60,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75 (3) 

800 (6) 

0.19 (0.75) 

(continued) 

^ 
TABLE 3. (continued) 

Plant size 

Parameters Small Medium Large 

4. Chevron-blade mist eliminator with double 0.5 (2) 0.5 (2) 0.5 (2) 

set of blades, AP, kPa (in . w.c.) 

5. Mesh-pad mist eliminator, AP, kPa (1n. w.c.) 0.25 (1) 0.25 (1) 0.25 (1) 

F. Stack 

Number of stacks 1 1 3 

Height, m (ft)1" 9.1 (30) 9.1 (30) 9.1 (30) 

Diameter, m (ft) 1.0 (3.3) 1.1 (3.8) 0.4 (1.3) 

1.1 (3.7) 

1.6 (5.2) 

Temperature, °C (°F) 27 (80) 27 (80) 27 (80) 

Moisture, % 2 2 2 

Gas flow rate, m/min (ft/min ) 736 (26,000) 991 (35,000) 113 (4,000) 

850 (30,000) 

1,700 (60,000) 

Gas velocity, m/min (ft/min) 914 (3,000) 914 (3,000) 914 (3,000) 

Parameter values for the small, medium, and large plant sizes are based on information obtained from 

.nine, four, and three plants, respectively. 

^Tank freeboard space=6 inches. 

cFor the large model plant, the two 1.2-m (4-ft), five 3.6-m (12-ft), and three 7.6-m (25-ft) tanks are 

vente^j to three separate control devices with ventilation rates of 113 m /min (4,000 ft /min), 

850 m /min (30,000 ft /min), and 1,590 m/min (56,250 ft/min), respectively. 

Model plant parameters are presented for all control techniques. Any one may be used at any given 

plant. 

^Ventilation rates were rounded to the gas flow rates for which factory-assembled units are available. 

Stack height is the distance from ground level to the point of discharge. 
TABLE 4. MODEL PLANT PARAMETERS FOR CHROMIC ACID ANODIZING OPERATIONS3 

Parameters 

A. Production rate 

Time electrodes are energized, % 

Chromic acid usage, kg/yr (lb/yr) 

B. Operating time 

Hours/day 

Days/week 

Weeks/year 

Hours/year 

C. Process 

Number of tanks 

Tank dimensions, (1, w, d) , m (ft) 

Total tank capacity, a (ga])c 

Total tank surface area, m (ft ) 

Chromic acid concentration, g/a (oz/gal) 

Temperature of plating solution, °C (°F) 

Operating voltage, V 

D. Emission capture system 

Type of hood 

Ventilation rate, m /min (ft /min) 

E. Control technique 

1. Chemical fume suppressant usage, kg/yr (lb/yr) 4.5 (10) 45 (100) 

" ~~ (continued) 

Plant 

Small 

25 

900 (2,000) 

8 

5 

50 

2,000 

1 

3.6, 1.1, 1.8 

(12.0, 3.5, 6.0) 

6,550 (1,730) 

3.9 (42) 

75 (10) 

32-35 (90-95) 

40 

Double-sided lateral 

297 (10,500) 

size 

Large 

b 

5,670 (12,500) 

24 

6 

50 

7,200 

2 

2 9 9.1, 1.5, 2.7 

(30.0, 5.0, 9.0) 

72,190 (19,070) 

28 (300) 

75 (10) 

32-35 (90-95) 

20 

Push-pull 

1,060 (37,500) 

p 

Tl 
TABLE 4. (continued) 

fc 

Plant size 

Parameters 

2. Control device 

Number of control devices 

Inlet gas flow rate, m /m1n (ft /min) 

Inlet gas temperature, °C (°F) 

Inlet gas moisture, % 

a. Single packed-bed scrubber, AP , kPa (in. w.c.) 

Liquid-to-gas ratio, a/1,000 m , (gal/1,000 ft ) 

b. Double packed-bed scrubber, AP S kPa (1n. w.c.) 

Liquid-to-gas ratio, a/1,000 m 

c. Chevron-blade mist eliminator with single set 

of blades, AP, kPa (in. w.c.) 

d. Chevron-blade mist eliminator with double set of 

blades, AP, kPa (in. w.c.) 

e. Mesh-pad mist eliminator, AP, kPa (in. w.c.) 

F. Stack 

Number of stacks 

Height, m (ft)e 

Diameter, m (ft) 

Temperature, °C (°F) 

Moisture, % 

Gas flow rate, m /min (ft /min) 

Gas velocity, m/min (ft/min) 

Small 

1 

340 (12,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75 (3) 

800 (6) 

0.19 (0.75) 

0.5 (2) 

0.25 (1) 

1 

9.1 (30) 

0.7 (2.3) 

27 (80) 

2 

340 (12,000) 

914 (3,000) 

Large 

1 

1,133 (40,000) 

27 (80) 

2 

0.5 (2) 

400 (3) 

0.75 (3) 

800 (6) 

0.19 (0.75) 

0.5 (2) 

0.25 (1) 

1 

9.1 (30) 

1.2 (4.1) 

27 (80) 

2 

1,133 (40,000) 

914 (3,000) 

Parameter values for the small plant size are based on Information obtained from 16 plants, and those 

for the large plant size are based on information from one plant. 

Data not available from plants contacted. 

^Tank freeboard space=6 inches. 

Model plant parameters are presented for all control techniques. A fume suppressant alone or in 

combination with a scrubber or mist eliminator may be used at any given plant. 

eStack height is the distance from ground level to the point of discharge. 

*• 
P.15 

14 

TABLE 5. VENTILATION RATES FOR MODEL TANK EMISSION CAPTURE SYSTEMS 

Dimensions V^ntilatiog rate, 

(1, w, d) , m (ft) Type of hood m /min (ft /min) 

1.2, 1.2, 3.0 Push-pull Push <2.3 (<80) 

(4.0, 4.0, 10.0) Pull 57 (2,000) 

3.6, 1.1, 1.8 Double-sided lateral 297 (10,500) 

(12.0, 3.5, 6.0) 

3.6, 1.2, 1.8 Push-pull Push <6.8 (<240) 

(12.0, 4.0, 6.0) Pull 170 (6,000) 

3.6, 1.8, 2.7 Push-pull Push <10 (<360) 

(12.0, 6.0, 9.0) Pull 255 (9,000) 

7.6, 0.9, 1.8 Double-sided lateral 531 (18,750) 

(25.0, 3.0, 6.0) 

9.1, 1.5, 2.7 Push-pull Push <21 (<750) 

(30.0, 5.0, 9.0) Pull 531 (18,750) 

/V 
15 

P.16 

TABLE 6. NUMBER, SIZE, AND TOTAL VENTILATION RATES OF MODEL TANKS VENTED 

TO A COMMON CONTROL DEVICE 

Model plant 

Decorative plating 

Small 

Medium3 

Largeb 

Hard plating 

Small0 

Medium0 

Larged 

Anodizing 

Small 

Largec 

No. 

1 

1 

1 

1 

1 

2 

2 

1 

1 

1 

2 

1 

2 

5 

3 

1 

2 

Model tanks 

Tank dimensions 

(1, w, d), m (ft) 

3.6, 1.1, 1.8 (12.0, 3.5, 6.0) 

3.6, 1.1, 1.8 (12.0, 3.5, 6.0) 

3.6, 1.1, 1.8 (12.0, 3.5, 6.0) 

3.6, 1.1, 1.8 (12.0, 3.5, 6.0) 

3.6, 1.8, 2.7 (12.0, 6.0, 9.0) 

3.6, 1.8, 2.7 (12.0, 6.0, 9.0) 

3.6, 1.8, 2.7 (12.0, 6.0, 9.0) 

3.6, 1.2, 1.8 (12.0, 4.0, 6.0) 

7.6, 0.9, 1.8 (25.0, 3.0, 6.0) 

1.2, 1.2, 3.0 (4.0, 4.0, 10.0) 

3.6, 1.2, 1.8 (12.0, 4.0, 6.0) 

7.6, 0.9, 1.8 (25.0, 3.0, 6.0) 

1.2, 1.2, 3.0 (4.0, 4.0, 10.0) 

3.6, 1.2, 1.8 (12.0, 4.0, 6.0) 

7.6, 0.9, 1.8 (25.0, 3.0, 6.0) 

3.6, 1.1, 1.8 (12.0, 3.5, 6.0) 

9.1, 1.2, 2.7 (30.0, 5.0, 9.0) 

Total ventilation rate per 

control device, 

m/min (ft/min) 

297 (10,500) 

297 (10,500) 

297 (10,500) 

297 (10,500) 

255 (9,000) 

510 (18,000) 

510 (18,000) 

701 (24,750) 

927 (32,750) 

113 (4,000) 

850 (30,000) 

1,593 (56,250) 

297 (10,500) 

1,062 (37,500) 

3Each of the three tanks is vented to a separate control device. 

One tank is vented to one control device, and two tanks each are vented 

to a second and a third control device. 

°A11 tanks are vented to one control device. 

dThe two 1.2-m (4.0-ft) long tanks, five 3.6 m (12.0-ft) long tanks, and 

three 7.5-m (25.0-ft) long tanks are vented to separate control devices. 

/*" 
TABLE 7. BASELINE LEVELS OF CONTROL FOR CHROMIUM PLATING AND ANODIZING OPERATIONS 

Plant size 

Smal I Med i um 

Operation/control technique No. 

12 

37 

2 

24 

11 

155 

18 

7 

39 

5* 

9 

5 

2 

73 

Percent 

14.0 

43.0 

2.3 

27.9 

12.8 

100.0 

28.1 

11.0 

60.0 

99.0 

56.3 

31.2 

12.5 

100.0 

Large Total 

No. Percent No. Percent No. 

12 

41 

2 

39 

13 

T07 

20 

8 

61 

B9 

10 

5 

2 

T7 

Percent 

11.2 

38.3 

1.9 

36.4 

12.1 

99.9 

22.5 

9.0 

68.5 

100.0 

58.8 

29.4 

11.8 

100.0 

Decorative plating 

Uncontrolled 

Fume suppressant 

Fume suppressant and mist eliminator 

Fume suppressant and scrubber 

Scrubber 

Total 

Hard plating 

Uncontrolled 

Mist eliminator 

Scrubber 

Total 

Anodizing 

Uncontrolled 

Fume suppressant 

Scrubber 

Total 

0 

3 

0 

11 

1 

T5 

1 

0 

14 

T5 

0.0 

20.0 

0.0 

73.3 

6.7 

TOO 

6.7 

0.0 

93.3 

TOO 

1 

1 

8 

TO 

1 

0 

0 

T 

0.0 

16.7 

0.0 

66.6 

16.7 

100.0 

10.0 

10.0 

80.0 

TTTCOJ 

100.0 

0.0 

0.0 

TOO 

a. 

CN Tl