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ACKNOWLEDGEMENTS

The project leader was Shobna Sahni with ARB Stationary Source Division. The 

sampling team was led by David Todd and included Don Ridgley and Ron Barros with 

the ARB Monitoring and Laboratory Division (MLD). Betsy Ronsee and Roxana Walker 

with MLD Northern Laboratory Branch conducted the laboratory analysis. Dominick 

Nole and Paramo Hernandez of Alta Plating and Anodizing provided plating bath 

surface tension and chromium content analysis.

This report presents results based on samples collected and analyzed by the Air 

Resources Board (ARB) staff using ARB test methods. The results have been reviewed 

by the staff and are believed to be accurate within the limits of the methods. However, 

data may have been affected by variables that were not known to staff during sampling 

and review.
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California Environmental Protection Agency

AIR RESOURCES BOARD

Monitoring and Laboratory Division

TABLE OF CONTENTS

I. INTRODUCTION.................................................................................................. 1 

II. PROCESS DESCRIPTION................................................................................... 1 

III. SHERM'S PLATING SOURCE TEST................................................................... 2 

IV. TEST METHODS ................................................................................................. 4 

V. QUALITY ASSURANCE / QUALITY CONTROL .................................................. 6 

VI. TEST RESULTS................................................................................................... 8 

TABLES AND FIGURES

FIGURE II-1 Front View of Decorative Chromium Plating Tank ................................... 2 

FIGURE III-1 Capture Hood Assembly .......................................................................... 3 

TABLE VI-1. ARB Method 425 Test Results................................................................ 9 

TABLE VI-2. Indoor Ambient Cr(VI) Data................................................................... 10

APPENDICES

A. Individual Test Run Summaries and Results

B. Field Data Sheets

C. ARB Laboratory Results

D. Capture Hood Drawing

E. Sample of Chain of Custody Sheet and Chain of Custody Log

F. Test Run Data Provided by ARB/SSD

G. Recovery Moisture Content Data Sheet
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California Environmental Protection Agency

AIR RESOURCES BOARD

Monitoring and Laboratory Division

Total and Hexavalent Chromium Emissions from 

Sherm's Custom Plating

Decorative Chromium Plating Tank

I. INTRODUCTION

At the request of the Air Resources Board (ARB) Stationary Source Division (SSD), staff 

of the Monitoring and Laboratory Division (MLD) performed emissions testing of a 

decorative chrome electroplating tank operated by Sherm's Custom Plating located at 

2140 Acoma Street in Sacramento, California. Emissions tests for total and hexavalent 

chromium were conducted from March 8 through March 11, 2004.

II. PROCESS DESCRIPTION

Sherm's Custom Plating performs decorative chromium plating on a variety of small 

parts. Sherm’s decorative chrome plating tank has a capacity of 607 gallons and is 95 

inches long, 41 inches wide, and 36 inches deep (See Figure II-1). Freeboard depth 

averaged 4.1 inches throughout the emissions testing. The plating tank is equipped 

with its own adjustable current and voltage rectifier. Plating bath temperature was 

maintained at approximately 110°F during plating operations. SSD staff periodically 

collected amperage, bath temperature, and amp-hour readings for the plating tank 

during the source test (see Appendix F). 

Plating tank emissions are controlled with a chemical fume suppressant (Protab 1000 

manufactured by MacDermid) that decreases the bath surface tension reducing the 

escape energy of the chromic acid mist generated during plating operations. No 

additional emissions controls are used (i.e., tank ventilating system). Emissions from 

the plating tank vent to the work area. A large ventilation fan on a distant wall pulls the 

air outside the facility. 
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Figure II-1 

Front View of Decorative Chromium Plating Tank

III. SHERM'S CUSTOM PLATING CHROMIUM SOURCE TEST 

The source test consisted of three sample runs collected from Sherm's Custom Plating’s 

decorative chrome plating tank between March 9-11, 2004. Set up and preliminary 

equipment checks took place the day before. The average plating solution surface 

tension during the test runs was 36.7 dynes/cm which is normal for this facility.

ARB Method 425 was used to determine hexavalent and total chromium emissions 

collected during the source tests. Sample runs one and two were continuously sampled 

for 360 minutes, whereas, sample run three was reduced to 312 minutes. During 

sampling, production or “dummy” parts were plated in the tank. The mix of production 

and dummy parts was necessary to obtain a target of about 400 ampere-hours per run. 

Sherms prepared each dummy part for plating in the same manner as production parts, 

and repeated the preparation each time the part reentered the plating tank.

ARB staff fabricated a ventilation system to direct plating tank emissions to the source 

sampling area (see Figure III-1). The system consisted of a capture hood with an open 

bottom, plastic-sheeted top and sides, and an opened front with minor additions of 

plastic strips to contain the emissions. A 12-inch diameter flexible exhaust duct, ported 

on top of the hood, directed emissions from the tank to a sample collection area and 

then vented the exhaust inside the facility fifteen feet beyond the sampling area. The 

fabricated ventilation system was designed to allow droplets to return to the tank but yet 

collect fumes floating above it. (Note: As per South Coast AQMD procedures for plating 

tanks and fume suppressant certification, the average "lift" velocity between the tank 

and the ventilation system should be less than 50 feet/minute.).

PQ-100 Ambient 

Air Sampler 

Location

Chromium 

Plating Tank
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The capture hood was suspended from the ceiling rafters which allowed relatively 

uninhibited access for the workers. Its top dimensions were slightly smaller than the 

tank top opening. The backside of the tank was totally enclosed by either the hood's 

plastic sheeting or the tank's plastic splash panel. The right side was enclosed the 

same way except for a 10-inch high (approximately 2 square feet) opening at the bottom 

in the tank's plastic splash panel. One third of the left side splash panel (approximately 

3.6 square feet) was opened to allow easy access to the adjacent rinse tank. The front 

of the hood was totally opened for access except for some draped plastic sheeting in 

the upper right corner needed to contain air currents detected during smoke tests (see 

Appendix D, Hood Drawing).

The 12-inch diameter PVC flexible ducting had a 27-inch inside radius arc (180o) from

the top of the hood to the top of the vertical 67-inch PVC sampling duct. The sampling 

duct rested on top of a fan box with a variable motor controller. Method 425 samples 

were collected from two 3-inch diameter holes cut 90 degrees apart into the sampling 

duct, 18 inches (11⁄2 diameter) above the fan box and 49 inches (4 diameter) below the 

flexible/rigid duct connection. The emissions are directed out of the fan into the inside 

of the building. Inside air is removed by the facility's ventilation system.

Figure III-1 

Rear View of Fabricated ARB Capture Hood Assembly

(Shown before installation at Sherm's Custom Plating)

Hood (Rear 

View)

Sample Ports

Fan & 

Controller

Exhaust
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The capture hood was designed to capture plating tank emissions having less than 50 

feet per minute of vertical lift above the plating tank. Fifty feet per minute under the 

hood equals 1,367 cubic feet per minute (cfm) at the sample collection point. The 

actual average three-day source test flow at the collection point was 957cfm. Smoke 

tests were conducted during each test run to ensure no emissions leaked from the 

hood. The smoke did not contain any chromium or other compounds that would 

interfere with chromium sampling and analysis.

Indoor ambient samples were collected concurrently with the three source test runs. 

Samples were collected on sodium bicarbonate-impregnated filters. The BGI, Inc. PQ100 ambient sampler was set on top of the rectifier next to the decorative chrome tank. 

Indoor ambient samples were analyzed for hexavalent chromium only. One indoor 

ambient sample was collected with each source test stack sample. Another three 

indoor ambient samples were collected March 17-19, 2004, after the source sampling 

was completed and the capture hood removed.

IV. TEST METHODS

A. Source Sampling Procedure

Samples were collected and recovered by the ARB Stationary Source Testing 

Branch. Stack and duct flows were determined by ARB Stationary Source Test 

Method 1 (velocity traverse), Method 2 (stack velocity and flow rate), Method 3 

(stack gas dry molecular weight), and Method 4 (moisture content). For Method 3, 

atmospheric concentrations of carbon dioxide, nitrogen, and oxygen were used to 

determine dry molecular weight. 

Hexavalent and total chromium samples were collected isokineticaly in accordance 

with ARB draft Method 425, “Determination of Total Chromium and Hexavalent 

Chromium Emissions from Stationary Sources. ARB Method 425 was originally 

adopted January 22, 1987, and amended August 27, 2002. ARB draft Method 425 

incorporates several approved modifications from the current amended version. 

These include the use of unheated sample lines and probes, the use of 0.1 N 

sodium bicarbonate impinger solution in place of 0.1 N sodium hydroxide solution, 

and deletion of the sample train filter and filter heater. 

The chromium sampling train configuration consisted of the following:

• a glass 3/8-inch nozzle; a Teflon union, a 48 inch glass-lined stainless steel 

probe (with attached pitot tube and thermocouple);

• a ten-foot Teflon line from the probe to the first of two Greenburg-Smith 

impingers, each containing 100 milliliters of 0.1 normal (N) sodium 

bicarbonate solution;
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• an empty impinger;

• a silica gel holder;

• a 50 foot umbilical line; and

• a sampling console consisting of a vacuum pump, dry gas meter, calibrated 

orifice connected to an inclined oil manometer, and additional monitors and 

controls for collecting a sample isokinetically.

Each of the three days consisted of either 360 minute test runs (test runs 1 and 2) or 

a 312 minute test run (test run 3) using a single sample train. An additional blank 

impinger train was assembled adjacent to test run 2's impinger train (QA control). 

In accordance with Method 1, the sampling location required 24 traverse points, 12 

sampling points on each diagonal ninety degrees apart.

In accordance with Method 2, thermocouples and Type S pitot tubes bundled with 

the sampling probes were used to determine stack velocity. The weight of the 

impinger solutions and silica gel were recorded before and after each test to obtain 

the gas stack moisture content as required by Method 4. In addition, stack 

temperature, ambient temperature, and barometric pressure were measured and 

recorded during each test. Leak checks were performed on each sample train and 

pitot tube assembly before and after each sample collection. 

After sampling, rinses of the sampling train nozzle, probe and transfer line, as well 

as the catch from the impingers, were recovered into three 500-ml glass sample jars 

as follows (all sample jars were pre-cleaned and tested to ensure the absence of 

chromium prior to the source test):

• Container 1 – rinses from the nozzle, sample probe, and transfer line;

• Container 2 – first impinger catch; and

• Container 3 – second and third impinger catch. 

The pH of the sodium bicarbonate solution used for the probe rinse and impingers 

was maintained at ≥ 8.0. Additionally, the impinger solution was chilled with ice to 

4°C (39°F) or less during sample collection. All samples were also chilled with ice 

and refrigerated to 4°C (39°F) or less during transport and storage prior to analysis 

to minimize the conversion of hexavalent chromium to trivalent chromium. During 

sample recovery prior to analysis, disposable vinyl gloves were worn to help prevent 

contamination. At the conclusion of each sampling day, staff transported the 

collected samples to the laboratory for analyses.

The current supplied by the rectifier was monitored and recorded by SSD staff 

during the source test runs. SSD also recorded tank temperature and totalizer amp-
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hours. Additionally, plating bath samples were collected and analyzed by Alta 

Plating to determine plating bath surface tension and chromic acid content.

B. Indoor Ambient Sampling

Indoor ambient samples were collected on 47 mm filters using a PQ-100 ambient 

sampler. The filters were specially treated with sodium bicarbonate to preserve the 

sample for hexavalent chromium analysis. Indoor ambient samples were collected 

in parallel with the plating source test. Because the capture hood interfered with 

normal plating tank emissions, three additional samples were collected after the 

hood was removed. After sampling, the filters were placed back into their storage 

cassettes using sterile gloves and returned to the laboratory for analysis.

C. Analytical Procedures

The plating tank stack emissions were analyzed for both hexavalent and total 

chromium. The indoor filters were extracted into a solution and analyzed for 

hexavalent chromium only using the same procedure as the stack sample. 

Laboratory analyses for hexavalent and total chromium of the collected samples was 

performed by ARB’s Northern Laboratory Branch. Hexavalent chromium (also 

known as hex chrome, Cr (VI), or Cr+6) was measured using ion chromatography 

(IC) in accordance with ARB standard operating procedure (SOP), MLD039. The 

limit of detection (LOD) of the analytical procedure for hexavalent chromium is 0.2 

nanograms per milliliter (ng/ml). Total chromium was determined using an atomic 

absorption/ graphite furnace (GFAA) technique. To deal with the high carbonate 

fixative concentrations, staff used a variation of ARB SOP MLD005. The LOD of the 

analytical procedure for total chromium is 1.0 ng/ml. 

V. QUALITY ASSURANCE / QUALITY CONTROL

To ensure that data collected are consistent, relevant, and defensible, appropriate field 

and laboratory Quality Assurance (QA) procedures were followed throughout the source 

test. A detailed explanation of the ARB’s standard field and laboratory QA procedures 

are contained in ARB Quality Assurance manuals, Stationary Source Test Methods, and 

laboratory SOPs. 

As required by ARB Method 425, all surfaces that came into contact with a sample were 

either glass or Teflon and were pre-cleaned using the following procedure:

• the glassware was first washed with detergent;

• soaked with a 10% solution of nitric acid for several hours;

• flushed with liberal amounts of tap water;

• rinsed with de-ionized water; and

• rinsed with 0.1 N sodium bicarbonate solution. 
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To ensure that the sampling equipment was clean and free of chromium contamination, 

a sample of the final sodium bicarbonate rinse was analyzed for total hexavalent 

chromium (Cr). If any Cr was detected in the final rinse, all sampling equipment were 

re-cleaned until a sample of the final rinse contained no detectable Cr. In addition, extra 

pre-cleaned equipment was deployed to ensure that no equipment needed to be recleaned or re-used during field sampling. 

Baseline and post source tests were performed on the ARB capture hood and ducting in 

the 1900 14th Street warehouse before and after sampling at Sherm's. The purpose for 

these tests was to ensure no chrome contamination from the hood and ducting. The 

baseline test was conducted February 6, 2004. Results indicated less than the LOD for 

both total and hexavelent chromium. The post-test was conducted March 17, 2004. 

Small amounts (right at the LOD) of hexavalent chromium were detected in the first 

impinger rinse with the probe rinse slightly higher (see Appendix C, ARB Laboratory 

Results).

The sampling console used during the source test was calibrated December 23, 2003. 

A post-test calibration was performed March 23, 2004. The Type S pitot tubes used for 

stack velocity determinations met the required specifications for a baseline coefficient of 

0.84 as specified in ARB Method 2. The console assembly, including pitot tubes, 

passed leak checks before and after each velocity determination. In addition, all 

sampling train assemblies passed leak checks before and after each test. 

Prior to deploying to the field, MLD laboratory analysis verified chromium content in the 

sodium bicarbonate solution (used for recovery and impinger catches) was below the 

LOD. Although planned, staff did not collect and submit to the laboratory a blank 

sample of the sodium bicarbonate solution used for sample recovery during the week of 

testing. However, an analysis of the blank collected in parallel with test run 2 and the 

laboratory analysis of the second and third impinger catch for all tests was below the 

LOD which establishes the purity of the sodium bicarbonate solution.

All test samples were collected using an iced impinger set. After recovery, samples 

were stored on ice to maintain their temperature at or below 4 °C (39 °F) as required by 

ARB Method 425. Collected and recovered samples remained on ice while on site and 

during transport to the laboratory for analyses. Staff of the Northern Laboratory Branch 

ensured that the samples were maintained at or below 4 °C (39 °F) while awaiting 

analysis.

During sample collection and transport, the pH of the sodium bicarbonate solution used 

for the probe rinse and impinger charging was maintained at ≥ 8.0 as required by 

Method 425. This is necessary to ensure that any collected hexavalent chromium is not 

reduced to trivalent chromium. The pH of the impinger solutions was checked before 

sampling, after sample recovery, and during transfer to the laboratory. 
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Chain of custody was maintained for all collected samples. A chain of custody sheet 

was prepared for each sample train and a copy of the sheet for run number one is 

included in Appendix E as an example.

VI. TEST RESULTS

Results of the ARB Method 425 source tests for the Sherm's Custom Plating decorative 

chromium plating tank are presented in Table VI-I. The measured emission rates 

ranged from 0.046 to 0.053 milligrams per amp-hour (mg/amp-hr) for total chromium 

and 0.046 to 0.056 mg/amp-hr for hexavalent chromium. 

Indoor ambient results are presented in Tables VI-2a and VI-2b. Copies of run sheets 

are in Appendix A. Field data sheets are in Appendix B. Laboratory results are 

presented in Appendix C. Additional plating tank information is in Appendix F.
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Table VI-1

Sherm's Custom Plating Decorative Chromium Plating Tank Results Sampling 

Dates--March 9, 10, & 11, 2004

Sampling Location Chromium 

Plating tank

Chromium 

Plating tank

Chromium 

Plating tank

 Sample Date March 9, 2004 March 10, 2004 March 11, 2004

 Sample Number S-1 S-2 S-3

Plating Tank Data

 Totalizer (amp-hours) 415 459 425

 Production Rate (amp-hrs/hr) 69.2 76.5 81.7

 Freeboard (inches to overflow)* 5.0-4.9 3.0-3.5 4.0-4.0

 Chromic Acid Conc. (oz/gal) 34.2 32.6 Not Done

 Temperature (oF) 109.5 109.8 109.8

 Surface Tension (dynes/cm)* 35.6-35.9 37.5-35.9 37.8-37.9

Stack Data

 Stack Temp. (oF) 75 75 72

 Velocity (ft/sec) 19.49 22.19 20.33

 Static Pressure ("H2O) -0.23 -0.29 -0.19

 Stack Area (sq. ft.) 0.785 0.785 0.785

 Flow Rate (DSCFM) 904 1030 943

 Moisture (% of v/v) 1.1 0.6 1.0

Sampling Data

 Sampling Time (minutes) 360 360 312

 Sampling Volume (DSCF) 330.08 360.50 295.40

 Chromium Data (ng/sample)

 Total Chromium 19,440 22,600 22,730

 Hexavalent Chromium 19,413 21,490 23,693

 Isokinetic Ratio(%) 103.9 99.6 102.9

EMISSIONS

Concentration (ng/DSCF)

 Total Chromium 58.89 62.69 76.95

 Hexavalent Chromium 58.81 59.61 80.21

Emission Rate (mg/hr)

 Total Chromium 3.19 3.87 4.35

 Hexavalent Chromium 3.19 3.68 4.54

Emission Factors

(mg/amp-hr)**

Total Chromium 0.046 0.051 0.053

 Hexavalent Chromium 0.046 0.048 0.056

DSCF means dry standard cubic feet at 68oF and 29.92" Hg. DSCFM means dry standard cubic feet per 

minute.

*Paired values separated by a hyphen are "start-end" of day measurements.

**Emission Factor = Emission rate/Production rate.
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Table VI-2a

Sherm's Custom Plating

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results

Ambient sampling during source testing with the hood in place

Sample Number: S1-A S2-A S3-A

Sample Date: 03/09/2004 03/10/2004 03/11/2004

Sampling Time (minutes) 300 335 300*

Volume Collected (liters) 3000 3350 3000

Cr (VI) Collected (nanograms) 200 130 190

Indoor Ambient Concentration (ng/m3) 67 39 65

* Note: Difference between the annotated start and stop time does not equal 300 

minutes. It is assumed the start time was written incorrectly since the sampling interval 

is read directly from the PQ-100.

Table VI-2b

Sherm's Custom Plating

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results

Ambient sampling after source testing with the hood removed

Sample Number: S11-A S12-A S13-A

Sample Date: 03/19/2004 03/20/2004 03/21/2004

Sampling Time (minutes) 393 417 340

Volume Collected (liters) 3930 4170 3400

Cr (VI) Collected (nanograms) 390 870 410

Indoor Ambient Concentration (ng/m3) 100 210 120