Processes Tested: 

Mineral Wool Manufacturing 

Locations Monitored: 

Afterburner Stack 

Comprehensive 

Emissions Test Report

Afterburner Stack 

USG Interiors, Inc. 

Red Wing, Minnesota 

Carbon Monoxide & Sulfur Dioxide 

 Engineering Testing 

Test Date: September 13, 2005 

Report Date: September 23, 2005

Prepared for: 

Larry Dettmer 

USG Interiors, Inc. 

(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. 0509-102 
Table of Contents

Report Cover 1 

Table of Contents 2 

Executive Summary 3 

Introduction 4 

Results Summary 5 

Detail Tables 6 

 

 Table 1 CO & SO2 Determinations, Afterburner Stack 7 

 Table 2 Airflow Determinations, Afterburner Stack 8 

Process Description 9 

 

Test Procedures 10 

 Figure 1 Test Location Schematic, Afterburner Stack 13 

Signatures 14 

Appendix A Field Data Sheets 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 

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Executive Summary

USG Interiors contracted Pace Analytical Services, Inc. to perform Carbon Monoxide 

(CO) and Sulfur Dioxide (SO2) emissions engineering testing on the afterburner stack at 

the USG Interiors facility located in Redwing, Minnesota. Testing was performed on 

September 13, 2005. Summary results are highlighted in the following table: 

Test Results Summary

Parameter Run 1 Run 2 Run 3 Average

Volumetric Airflow 

 

 ACFM 65160 78530 72780 72160 

 SCFM 18310 22450 18270 19680 

 DSCFM 16960 20790 16910 18220 

Emission Rate (LB/HR) 

 

 CO 0.21 <0.09 <0.07 <0.13 

 SO2 427 538 426 463 

Emission Concentration (PPM Dry) 

 

 CO 2.9 <1.0 <1.0 <1.6 

 SO2 2522 2591 2523 2546 

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Introduction

Pace Analytical Services, Inc. personnel conducted CO & SO2 emission engineering 

testing on the afterburner stack at the USG Interiors facility located in Redwing, 

Minnesota. James Trowbridge and Chris Norman performed on-site testing activities. 

Terry Borgerding provided administrative project management. Larry Dettmer with USG 

Interiors coordinated plant activities during testing. On-site activities consisted of the 

following measurements: 

- CO, three independent one-hour monitoring periods. 

- SO2, three independent one-hour monitoring periods. 

- Orsat gas composition, integrated gas samples collected concurrent with above. 

- Volumetric airflow, measurements during each constituent test run. 

The project objectives were to quantify CO & SO2 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 regulatory compliance testing requirements. 

Subsequent sections summarize the test results and provide descriptions of the process 

and test methods. Supporting information and raw data are in the appendices. 

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Results Summary

Results of CO & SO2 determinations are summarized in Table 1. The CO emission rate 

averaged 0.13 LB/HR at an average concentration of 1.6 PPM Dry. The SO2 emission 

rate averaged 463 LB/HR at an average concentration of 2546 PPM Dry. 

Subsequent tables provide expanded detail of the testing results. 

The data in this report are indicative of emission characteristics 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. 

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Detail Tables

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USG Red Wing

Red Wing, Minnesota CO & SO2 Determinations

Report Date: 9/23/05 Afterburner Stack

TEST 1

Parameter Run 1 Run 2 Run 3 Average

Date of Run 9/13/2005 9/13/2005 9/13/2005 9/13/2005

Time of Run 1315-1400 1659-1744 1812-1857

Sample Duration (Minutes) 45 45 45

Stack Temperature (°F) 1353 1322 1569 1415

Duct Moisture Content (%v/v) 7.4 7.4 7.4 7

Volumetric Flow Rate

 ACFM 65,180 78,540 72,770 72,160

 SCFM 18,320 22,450 18,270 19,680

 DSCFM 16,970 20,790 16,910 18,220

Compound Concentration

 mg/dscm

 CO 3.3 <1.2 <1.2 <1.9

 SO2 6721 6904 6724 6783

 PPM, Dry

 CO 2.9 <1.0 <1.0 <1.6

 SO2 2522 2591 2523 2546

Compound Mass Rate (LB/HR)

 CO 0.21 <0.09 <0.07 <0.13

 SO2 427 538 426 464

Table 1

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USG Red Wing

Red Wing, Minnesota Airflow Measurements

Pace Project No. 0509-102 Afterburner Stack

Report Date: 9/23/05 TEST 1

Parameter Run 1 Run 2 Run 3 Average

Date of Run 9/13/2005 9/13/2005 9/13/2005

Time of Measurement 1315 1630 1845 1315-1845

Number of Sampling Ports 2 2 2

Number of Points Sampled 16 16 16

Barometric Pressure (In. Hg) 28.97 28.97 28.97 28.97

Static Pressure (In. WC) -1.32 -1.44 -1.37 -1.38

Absolute Flue Gas Pressure (In. Hg) 28.87 28.86 28.87 28.87

Average Flue Gas Temperature (F) 1353 1322 1569 1415

Average Moisture Content (%v/v) 7.4 7.4 7.4 7.4

Dry Molecular Wt. of Gas (lb/lb-mole) 30.8 30.8 30.8 30.8

Flue Gas Average Velocity (FPS) 47.14 56.81 52.63 52.19

Duct Dimension (Inches) 65.0 65.0 65.0

Duct Cross-sectional Area (Sq. Ft.) 23.04 23.04 23.04

Volumetric Flow Rate

 ACFM 65,180 78,540 72,770 72,160

 SCFM 18,320 22,450 18,270 19,680

 DSCFM 16,970 20,790 16,910 18,220

Table 2

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Process Description

USG produces mineral wool at its plant in Red Wing. Mineral wool is produced by 

melting and fiberizing raw materials. The major component is slag, which is a byproduct from the steel industry. Stone is used as an additive to change the melt 

chemistry to produce the best quality wool for production. The mineral wool is then sent 

to other facilities to be made into products such as ceiling 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, the 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 process are the two cupolas, where the stone 

and slag are heated and melted with coke and the blow chambers where the wool fibers 

are collected. Cupola melt rate is limited to 22.07 tons/hr. Pollution control equipment 

for the cupolas include a baghouse and thermal oxidizer. Pollution control equipment for 

the blow chamber includes a dry 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 normal operating parameters. 

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Test Procedures

EPA Method 1 specifies test location acceptability criteria and defines the minimum 

number of traverse points for representative sampling. Linear measurements from 

upstream and downstream flow disturbances and the duct equivalent diameter are 

compared and the distances related to number of diameters. A flow disturbance can be 

defined as anything that changes or upsets the direction of flow within the duct including 

bends, dampers, fans, shape or size transitions and open flames. Method 1 stipulates 

that test ports should be located at least eight diameters downstream and two diameters 

upstream of any flow disturbance. The minimum acceptable criteria are two diameters 

downstream and 0.5 diameters upstream of flow disturbances. The test location must 

also be free of cyclonic or multidirectional flow. Once the distances have been 

determined, the values are used to select the minimum number of traverse points for 

representative sampling. Shorter distances require 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: 65” 

 Distance From Upstream Disturbance: ~1620“ 

 Number of Duct Diameters: ~24.9 

 Distance To Downstream Disturbance: ~204 “ 

 Number of Duct Diameters: ~3.1 

 Cyclonic or Multidirectional Flow: No, verified 

 Number of Traverse Points: 16

EPA Method 2 defines procedures used to measure linear velocity and volumetric flow 

rate of a confined gas stream. Using traverse points determined by EPA Method 1, 

multiple differential pressure measurements (pitot impact opening versus static 

pressure) are made using a pitot tube and differential pressure gauge. The individual 

measurements are averaged and combined with the gas density to calculate the 

average gas velocity. The velocity and duct cross-sectional area are used to calculate 

the volumetric flow rate. The volumetric flow rate is expressed as actual cubic feet per 

minute (ACFM), standard cubic feet per minute (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 3B defines procedures to quantify carbon dioxide (CO2) and oxygen (O2) 

concentrations from stationary combustion sources. A multi-point, integrated, gas 

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sample is collected simultaneously with other emissions testing. Using traverse points 

determined from EPA Method 1, sample gases are extracted from emission stream at a 

constant rate. Each point is sampled for a uniform length of time over the course of a 

test period equal to other test constituents. A TedlarTM, aluminized MylarTM or other 

inert material bag contains the collected gas sample prior to sample analyses. An Orsat 

gas analyzer quantifies the CO2 and O2 concentrations by measuring the changes in 

volume after selective chemical gas adsorption. Below are the details of the procedures 

for measuring gas composition: 

 Filter Material: Glass fiber filter or equivalent 

 Moisture removal: Condenser 

 Bag Material: Aluminized MylarTM 

 Gas Analyzer: Orsat 

EPA Alternative Method 4 defines procedures to measure the moisture content of 

emissions gas streams from stationary sources. The moisture content of the gas 

stream is determined using alternative Method 4. Wet bulb/dry bulb temperature 

measurements of the gas stream are recorded. Psychometric charts and vapor 

pressure of water tables are used to calculate the moisture content of the gas streams. 

EPA Method 6C defines procedures to measure sulfur dioxide (SO2) from stationary 

sources. A stainless steel sampling probe and a heat-traced 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 an API M600CLD ultraviolet 

gas analyzer to quantify SO2 emissions. Zero grade cylinder air provides zero gas and 

span gases include varying concentrations of EPA Protocol 1 SO2 standards. A 

computerized data acquisition system and stripchart recorder (in parallel) log SO2

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 SO2

testing include: 

 Probe Material: Stainless Steel 

 Moisture Removal: Thermo-electric 

 Transfer Line: TeflonTM 

Instrument: API M600CLD 

Analytical Technique: Ultraviolet detector 

Calibration Gas: EPA Protocol 1 

EPA Method 10 defines procedures to measure Carbon Monoxide (CO) emissions from 

stationary sources. A stainless steel sampling probe and a heat-traced 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 Thermo 

Environmental Instruments Model 48H non-dispersive infrared analyzer to quantify CO 

concentrations. Zero grade cylinder air provides zero gas and span gases include 

varying concentrations of EPA Protocol 1 CO standards. A computerized data 

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acquisition system and stripchart recorder (in parallel) log CO concentrations for oneminute 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 testing include: 

 Probe Material: Stainless Steel 

 Moisture Removal: Thermo-electric 

 Transfer Line: TeflonTM 

Instrument: TEI Model 48H 

Analytical Technique: Non-dispersive Infrared 

Calibration Gas: EPA Protocol 1 

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Report Signatures

Field Testing and Reporting Performed by: Pace Analytical Services, Inc. 

 Field Services Division 

1700 Elm Street, Suite 200 

 Minneapolis, MN 55414 

Field Testing Affirmation

All field testing was performed in accordance with stated test methods subject to modifications 

and deviations listed herein. Raw field data presented in this report accurately reflects results 

and information as recorded at the time of tests or otherwise noted. 

_________________________________ Date _____________ 

James Trowbridge 

Field Analyst 

Report Affirmation

To the best of my knowledge, this report accurately represents the compiled field and laboratory 

information with no material omissions, alterations or misrepresentations. 

Responsible Charge Affirmation

I have reviewed the information herein and it is approved for distribution. 

_________________________________ Date _____________ 

Terry Borgerding 

Operations Manager Air/Water 

Pace Analytical

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