Plant ID and Location:

USG Interiors, Inc. 27384 Highway 61 Red Wing, Minnesota

Permit: 04900007-003

Emission Sources: Cupola No. 1 (EU001) Cupola No. 2 (EU002)

Test Locations: Afterburner (EU001) Stack (SV009) 

# Comprehensive Emissions Test Report

Afterburner Stack USG Interiors, Inc Sulfur Dioxide and Carbonyl Sulfide Compliance Testing

Test Date: October 3, 2007

Report Date: October 8, 2007

Prepared for:

Angela Aalbers USG Interiors, Inc. 27384 Highway 61 Red Wing, Minnesota (651) 388-3513

Prepared by:

Pace Analytical Services, Inc. Field Services Division 1700 Elm Street, Suite 200

Minneapolis, MN 55414 (612) 607-1700

Pace Project No. 0708-107

## Table of Contents

Report Cover 1 Table of Contents 2

Executive Summary 3 Introduction 4 Results Summary 5

Summary Table 6 Table 1 Results Summary 7

Detail Tables 8 Table 2 Moisture Detail 9 Table 3 Airflow Detail 10

Process Description 11

Test Procedures 12 Figure 1 Test Location Schematic 16

Signatures 17

Appendix A Field Data Sheet s and Documentation A-1 Appendix B Quantitation and Laboratory Reports B-1 Appendix C Calculation Equations C-1 Appendix D Quality Assurance Information D-1 Appendix E Source/Process/ Plant Information E-1 Appendix F Test Protocol and Pretest Correspondence F-1

## Executive Summary

USG Interiors contracted Pace Analytical Serv ices, Inc. to perform sulfur dioxide (SO 2 ) and carbonyl sulfide (COS) emissions complianc e testing on the after burner stack at the USG Interiors facility located in Redwing, Minnesota. Testing was performed on October 3, 2007. Summary results ar e highlighted in the following table:

Test Results Summary

Parameter Run 1 Run 2 Run 3 Average

Volumetric Airflow

ACFM 67,550 70,930 68,640 69,040 SCFM 17,020 17,7490 17,250 17,340 DSCFM 15,480 16,370 15,890 15,910

Emission Rate (LB/HR)

SO 2 260 306 288 285 COS <0.11 <0.11 <0.11 <0.11

Emission Concentration (PPM Dry)

SO 2 1,683 1,870 1,819 1,791 COS <0.72 <0.72 <0.72 <0.72

COS Emission Limit 2.05 LB/HR SO 2 Emission Limit 371 LB/HR

## Introduction

Pace Analytical Services, Inc. personnel conducted SO 2 and COS emission compliance testing on the afterburner stack at the US G Interiors facility located in Red Wing, Minnesota. James Trowbridge, Terry Harrington and Adam Birr performed on-site testing activities. Terry Borgerding provi ded administrative project management. Larry Dettmer with USG Interiors coordinated plant acti vities during testing. On-site activities

consisted of the fo llowing measurements:

- SO2, three independent one-hour monitoring periods.

- COS, three independent one-hour monitoring periods.

- Moisture, three independent one-hour sampling periods.

- Orsat gas composition, integrated gas samples collected conc urrent with above.

- Volumetric airflow, measurements during each constituent test run.

The project objective s were to quantify SO 2 and COS emission constituents and compare them to applicable air emissions regulations stipulated by MPCA and the facility permit. These measurements were performed at normal operating condition. Quality protocols comply with all regul atory compliance test ing requirements.

Subsequent sections summarize the test resu lts and provide descriptions of the process and test methods. Supporting information and raw data are in the appendices.

## Results Summary

Results of SO 2 and COS determinations are summarized in Table 1. The SO 2 emission rate averaged 285 LB/HR at an average concentration of 1791 PPM Dry. The COS emission rate averaged <0.11 LB/HR at an average concentration of <0.72 PPM Dry. Subsequent tables provide expanded detail of the testing results.

The data in this report are indicative of emission char acteristics of the measured sources for process conditions at the time of the test. Representations to other sources and test conditions are beyond the scope of this report.

## Summary Table

## USG Interiors, Inc.
Red Wing, Minnesota Sulfur Determinations Pace Project No. 0708-107 A fterburner Stack (SV 009) Report Date: 10/8/07 TEST 1

Parameter Run 1 Run 2 Run 3 Average Date of Run 10/3/2007 10/3/2007 10/3/2007 10/3/2007 Time of Run 838-938 1018-1118 1200-1300 Sample Duration (Minutes) 60 60 60

Stack Temperature (°F) 1,578 1,592 1,583 1,584 Duct Moisture Content (%v/v) 9.0 7.7 7.9 8

Volumetric Flow Rate ACFM 67,550 70,930 68,640 69,040 SCFM 17,020 17,740 17,250 17,340 DSCFM 15,480 16,370 15,890 15,910

Compound Concentration mg/dscm SO2 4,485 4,984 4,846 4,772 COS <1.8 <1.8 <1.8 <1.8

PPM, Dry SO2 1,683 1,870 1,819 1,791 COS <0.73 <0.72 <0.72 <0.72

Compound Mass Rate (LB/HR) SO2 260 306 288 285 COS <0.11 <0.11 <0.11 <0.11 

## Table 1

## Detail Tables

## USG Interiors, Inc.
Red Wing, Minnesota Orsat and Moisture Details Pace Project No. 0708-107 A fterburner Stack (SV 009) Report Date: 10/8/07 Test 1

Paramete r Run 1 Run 2 Run 3 Date of Run 10/3/07 10/3/07 10/3/07 Time of Run 838-938 1018-1118 1200-1300 Run Duration (Minutes) 60.0 60.0 60.0

Orsat (%v/v) Dry Basis Carbon Dioxide 18.39 19.42 19.95 Oxygen 2.89 2.49 2.07 Carbon Monoxide * * * Nitrogen 78.72 78.09 77.99

WetBasis Carbon Dioxide 16.73 17.92 18.38 Oxygen 2.62 2.30 1.90 Carbon Monoxide * * * Nitrogen 71.61 72.07 71.85

Portable O 2 Monitor Average (%v/v ) 2.9 2.5 2.1 Average Flue Gas Temerature (°F) 1578 1592 1583

Metered Sample Volume (CF) 52.20 46.00 44.70 Dry Standard Sample Volume (DSCF) 49.75 43.42 41.88 Moisture Collected (ml) 105.0 77.0 76.0

Moisture Content (%v/v) 9.04 7.70 7.87

Molecular Weight of Flue Gas (lb/lb-mole) Dry 31.06 31.21 31.27 Wet 29.88 30.19 30.23

Fo 0.980 0.948 0.944

*Carbon monoxide was not measured, concentrations assumed less than 0.01%. 

## Table 2

## USG Interiors, Inc.
Red Wing, Minnesota Airflow Measurements Pace Project No. 0708-107 Afterburner Stack (SV 009) Report Date: 10/8/07 TEST 1

Parameter Run 1 Run 2 Run 3 Average Date of Run 10/3/2007 10/3/2007 10/3/2007

Time of Measurement 0838 1018 1200 0838-1200

Number of Sampling Ports 2 2 2

Number of Points Sampled 16 16 16

Barometric Pressure (In. Hg) 29.19 29.19 29.19 29.19

Static Pressure (In. WC) -1.26 -1.36 -1.31 -1.31

Absolute Flue Gas Pressure (In. Hg) 29.10 29.09 29.09 29.09

Average Flue Gas Temperature (F) 1578 1592 1583 1584

Average Moisture Content (%v/v) 9.0 7.7 7.9 8.2

Dr y Molecular Wt. of Gas ( lb/lb-mole ) 31.1 31.2 31.3 31.2

Flue Gas Average Velocity (FPS) 47.39 49.76 48.15 48.43

Duct Dimension (Inches) 66.0 66.0 66.0

Duct Cross-sectional Area (Sq. Ft.) 23.76 23.76 23.76

Volumetric Flow Rate ACFM 67,550 70,930 68,640 69,040

SCFM 17,020 17,740 17,250 17,340

DSCFM 15,480 16,370 15,890 15,910 

## Table 3

## Process Description

USG produces mineral wool at its plant in Red Wing. Melting and fiberizing raw materials produce mineral wool . The major component is slag, which is a by-product from the steel industry. Stone is used as an additive to change t he melt chemistry to produce the best quality wool for production. T he mineral wool is then sent to other facilities to be made into products such as ce iling tiles. USG has two cupolas for melting
raw materials. A cupola is a vertical cylindrical shaft furnace used to melt incoming minerals and then direct the molten slag out of a discharge notch. Once out of the notch, the molten slag (approximately 2600 o F) flows down troughs and is then placed on rotating wheels. As the wheel rotates, th e molten slag is forced off the wheel into a “wall” of air, which converts (fiberizes) the molten slag into fibers. Once the mineral wool is formed, it is collected in a large “Blow Chamber” (one for each cupola) and is baled for shipment.

Main emission sources involved in this pr ocess are the two cupol as, where the stone and slag are heated and melted with coke and the blow chambers wher e the wool fibers are collected. Cupola melt rate is limited to 22.2 LB/HR. Pollution control equipment for the cupolas include a baghouse and thermal ox idizer. Pollution control equipment for

the blow chamber includes a dr y filter system. After the air passes through the dry filter system, then it is exhausted to the atmosphere. The operating rates for the test were within the range of norma l operating parameters.

## Test Procedures

EPA Method 1 specifies test location acceptability criteria and defines the minimum number of traverse points fo r representative sampling. Linear measurements from upstream and downstream flow disturbances and the duct equival ent diameter are compared and the distances relat ed to number of diameters. A flow disturbance can be defined as anything that changes or upsets the direction of fl ow within the duct including bends, dampers, fans, shape or size transiti ons and open flames. Method 1 stipulates that test ports should be located at least ei ght diameters downstre am and two diameters upstream of any flow disturbanc e. The minimum acceptable criteria are two diameters downstream and 0.5 diameters ups tream of flow disturbances. The test location must also be free of cyclonic or multidirectiona l flow. Once the distances have been determined, the values are used to select the minimum number of traverse points for representative sampling. Shorter distances r equire a greater number of traverse points. The test site configuration is shown in Figure 1 and has the following characteristics:

Test Location: Afterburner Stack Duct Cross-sectional Dimension: 66” Distance From Upstre am Disturbance: 1398“ Number of Duct Diameters: 21.1 Distance To Downstream Disturbance: 294 “ Number of Duct Diameters: 4.5 Cyclonic or Multidirectional Flow: No, verified Number of Traverse Points: 16

EPA Method 2 defines procedures used to measure li near velocity and volumetric flow rate of a confined gas stream. Using tr averse points determined by EPA Method 1, multiple differential pressure measurem ents (pitot impact opening versus static pressure) are made using a pitot tube and diffe rential pressure gauge. The individual measurements are averaged a nd combined with the gas density to calculate the average gas velocity. The velocity and duct cross-sectional area ar e used to calculate the volumetric flow rate. The volumetric flow rate is expre ssed as actual cubic feet per minute (ACFM), standard cubic feet per minut e (SCFM), and dry standard cubic feet per minute (DSCFM). The technician maintains comprehensive test records on handwritten field data sheets. Details of the equipment used to measure gas velocity include:

Pitot Tube: S-Type Differential Pressure Gauge: Oil Manometer Temperature Device: Type K Thermocouple Barometer Type: Electronic Digital Barometer Gas Density Determination: EPA Method 3 Gas Moisture Determination: EPA Method 4

EPA Method 3A defines procedures to me asure carbon dioxide (CO 2 ) and oxygen (O 2 ) concentrations from stationary sources. A stainless steel sampling probe and a heattraced TeflonTM sampling line draw a sample of the gas stream from the duct to a thermo-electric gas conditioner to remove moisture. The sample gas stream is delivered to a Horiba infrar ed gas analyzer to quantify CO 2 concentrations. A Teledyne chemical cell gas analyzer quantified O 2 concentrations. Zero grade cylinder nitrogen provides zero gas and span gases include varying concentrations of EPA Protocol 1 CO 2 /O 2 standards. A computeriz ed data acquisition system and stripchart recorder (in parallel) log CO 2 /O 2 concentrations for one-minute averages. The logged results are integrated to test periods and tabulated with spreadsheet software. The operator also maintains comprehensive test records on handwritten field data sheets. Equipment used for CO 2 /O 2 testing include:

Probe Material: Stainless Steel Moisture Removal: Thermo-electric Transfer Line: TeflonTM Instrument: Servomex M1400 Analytical Technique: Paramagnetic Calibration Gas: EPA Protocol 1

EPA Method 4 defines procedures to measure the moisture content of emissions gas streams from stationary source s. A stainless steel sampli ng probe draws a sample of the gas stream from the duct to a series of impingers to condense the water vapor. The first two impingers initially contain deionized water and a third impinger is empty. A desiccant packed drying column follows the impingers to quantitatively collect the remaining moisture. An ice bath maintains the impinger train tem perature (outlet) at 68°F or less. Collected water condensat e is measured and discarded. Method 4 equations convert the condensed liquid volume to a gas volume. The water vapor volume compared with the dr y standard gas volume collect ed through the isokinetic train determines the moisture content of t he emissions gas stream and is reported in percent by volume.

Probe Material: Stainless Steel Impinger Train Material : Borosilicate glass Desiccant: Drierite Condensate Measur e: Graduated Cylinder Desiccant Measure: Electronic balance

EPA Method 6C defines procedures to m easure sulfur dioxide (SO 2 ) from stationary sources. A stainless steel sampling probe and a heat-traced TeflonTM sampling line draw a sample of the gas str eam from the duct to a thermo -electric gas conditioner to remove moisture. The sample gas stream is delivered to an API M100AH ultraviolet gas analyzer to quantify SO 2 emissions. Zero grade cylinder air provides zero gas and span gases include varying concentrations of EPA Protocol 1 SO 2 standards. A computerized data acquisition system and stri pchart recorder (in parallel) log SO 2 concentrations for one-minute averages. The logged results are integrated to test periods and tabulated with spreadsheet software. The operator also maintainscomprehensive test records on handwritten fi eld data sheets. Equipment used for SO 2 testing include:

Probe Material: Stainless Steel Moisture Removal: Thermo-electric Transfer Line: TeflonTM Instrument: API M100AH Analytical Technique: Ultraviolet detector Calibration Gas: EPA Protocol 1

EPA Method 320 defines procedures to speciate and quantify gas-p hase compounds using extractive Fourier Transform Infrared S pectrometry (FTIR). A probe and sample line of inert materials draw a sample gas stream from the source and continuously deliver it to a sample cell at a constant rate. Sample inte rface materials and application of heat depend on the constituents of interes t. Infrared energy di rected through the cell and returned to an interferometer classifies spectral separations based on the sample gas composition. Collected mid-range in frared interferograms are converted to absorbance spectra and compared to existing li brary reference standards to identify and quantify gas constituents. A diaphragm or rotary vane pum p downstream of the cell moves the gas sample through the interface components and safely to vent. Elevated interface temperatures inhibit condensation of moisture and volatile constituents when appropriate. Sample cell pressure is moni tored and maintained within ±10” WC of atmospheric. The FTIR operator completes Field Data Sheets as a comprehensive record of testing parameters.

Commercial and empirically gen erated (internal) library spectra provide the bases for qualitative identification. Multiple compounds can be id entified from sample spectra because each constituent has unique spectral features. Sample cell path length and absorbance magnitude establish the concentra tions of gas components. An ethylene calibration transfer standard (CTS) certifie s the cell path length when compared to reference standard spectra (k nown path length). The libr ary standards used in this project are located in the Me thod Map in Appendix D.include:

Test data are electronically recorded and stored as singl e beam, absorbance, residual, and interferogram spectra. Final test reports display tabula ted instrument concentration logs and handwritten field data. Te st data are archived by project.

Primary calibration gases are EPA Protocol 1 ethylene in nitrogen. Target constituent gas calibrations occur as appropriate, subjec t to availability. Appendix D presents calibration trials, matrix spiking, detection limit derivations and other quality procedures. Spectral interpretation empirically derives theoretical compoun d detection limits by applying a known standard until the visual pr esence of the compound reaches at least two times the baseline si gnal-to-noise ratio (SNR).

Quantitative uncertainties are listed for all sample spectra and are approximately ±30%. Classical least squares fit (CLSF) calc ulations through Autoquant Pro derive thereported uncertainties. Analytic al precision is also approx imately ±30%. Recovery of certified ethylene calibrat ion transfer standards verified precision on-site.

Based on project data quality objectives, EPA Method 320 was modified to exclude:

• Fractional Calibration Unce rtainties (FCU) calculations

• Fractional Method Uncertainties (FMU) calculations

• Root Mean Square Deviation (RMSD) calculations

• Bias of Spiking Calculations

Details of FTIR instrumentation are shown below.

Sample Flow Rate: ~1-3 L/min. Probe Material: Stainless steel Transfer Lines: Teflon (heated) Sample Cells: 10 Meter Optical Path Length Cell Windows: Zinc Selenide Sample Interface Temp.: ~250°F Instrument: Midac I2000 Gas Phase FTIR Detector: Mercury Cadmium Telluride (MCT) Wave Number Range: 4500 – 650 cm -1 Scans/Result: 16/64 Co-added Scans Resolution: 0.5 cm -1 Gain: 1

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