THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM Sy
EW
U.S. Environmental Protection Agency
HRTI
INTERNATIONAL
ETV Joint Verification Statement
TECHNOLOGY TYPE: BAGHOUSE FILTRATION PRODUCTS
APPLICATION:
COMPANY:
ADDRESS:
WEB SITE:
E-MAIL:
CONTROL OF PM2.5 EMISSIONS BY BAGHOUSE
FILTRATION PRODUCTS
TECHNOLOGY NAME: L3650
W. L. Gore & Associates, Inc.
101 Lewisville Road
P.O. ox 1100
Elkton,MD 21022
http://www.gore.com
cpolizzi@wlgore.com
PHONE: (410) 392-3300
FAX: (410) 398-6624
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative or improved environmental
technologies through performance verification and dissemination of information. The goal of the ETV
Program is to further environmental protection by accelerating the acceptance and use of improved and
cost-effective technologies. ETV seeks to achieve this goal by providing high-quality, peer-reviewed data
on technology performance to those involved in the design, distribution, financing, permitting, purchase,
and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; stakeholder groups, which
consist of buyers, vendor organizations, permitters, and other interested parties; and with the full
participation of individual technology developers. The program evaluates the performance of innovative
technologies by developing test plans that are responsive to the needs of stakeholders, conducting field or
laboratory tests (as appropriate), collecting and analyzing data, and preparing peer-reviewed reports. All
evaluations are conducted in accordance with rigorous quality assurance protocols to ensure that data of
known and adequate quality are generated and that the results are defensible.
The Air Pollution Control Technology (APCT) Verification Center is operated by RTI International
(RTI), in cooperation with EPA's National Risk Management Research Laboratory. The APCT
Verification Center evaluates the performance of baghouse filtration products (BFPs) used primarily to
control PM2 5 emissions (particles 2.5 urn and smaller in aerodynamic diameter). This verification
statement summarizes the test results for W. L. Gore & Associates, Inc.'s filter fabric L3650.
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W. L. Gore & Associates, Inc.L3650
VERIFICATION TEST DESCRIPTION
All tests were performed in accordance with the APCT Generic Verification Protocol for Baghouse
Filtration Products, available at http://etv.rti.org/apct/pdf/baghouseprotocol.pdf. The protocol is based on
and describes modifications to the equipment and procedures described in Verein Deutscher Ingenieure
(VDI 3926, Part 2), Testing of Filter Media for Cleanable Filters under Operational Conditions,
December 1994. The VDI document is available from Beuth Verlag GmbH, 10772 Berlin, Germany.
The protocol also includes requirements for quality management, quality assurance, procedures for
product selection, auditing of the test laboratories, and test reporting format.
Outlet particle concentrations from a test fabric were measured with an impactor equipped with
appropriate substrates to filter and measure PM2 5 within the dust flow. Outlet particle concentrations
were determined by weighing the mass increase of dust collected in each impactor filter stage and
dividing by the gas volumetric flow through the impactor.
Particle size was measured while injecting the test dust into the air upstream of the baghouse filter
sample. The test dust was dispersed into the flow using a brush-type dust feeder. The particle size
distributions in the air were determined both upstream and downstream of the test filter fabric to provide
accurate results for penetration through the test filter of PM2 5. All tests were performed using a constant
18.4 ± 3.6 g/dscm (8.0 ± 1.6 gr/dscf) loading rate, a 120 ± 6.0 m/h (6.6 ± 0.3 fpm) filtration velocity
[identical to gas-to-cloth ratio (G/C*)], and aluminum oxide test dust with a measured mass mean
aerodynamic diameter maximum of 1.5 urn (average of three impactor runs). All baghouse filtration
products are tested in their initial (i.e., clean) condition.
Each of the three test runs consisted of the following segments:
• Conditioning period - 10,000 rapid-pulse cleaning cycles,
• Recovery period - 30 normal-pulse cleaning cycles,
• Performance test period - 6-hour filter fabric test period with impactor.
VERIFIED TECHNOLOGY DESCRIPTION
The W. L. Gore & Associates, Inc. company provided the following information about their product. The
L3650 is a membrane/fiberglass fabric laminate with a weight of 22 oz/yd2 (746/ g/m2) and used in both
GORE® Filtration Products and PRISTYNE® Filter Media Type 6250**. Figure 1 is a photograph of the
fabric. Sample material was received as nine 46 x 91 cm (18x36 in.) swatches marked with the
manufacturer's model number, year, and month of manufacture, and cake side. Three of the swatches
were selected at random for preparing three test specimens 150 mm (5.9 in.) in diameter.
VERIFICATION OF PERFORMANCE
Verification testing of the W. L. Gore & Associates, Inc., L3650 filter fabric was performed during
October 18-25, 2005, for standard test conditions at the test facility of ETS, Incorporated, 1401
Municipal Road, Roanoke, VA 24012. Test conditions are listed in Table 1. The overall test results
summarized in Table 2 are the averages of three individual tests.
Filtration velocity and gas-to-cloth ratio are used interchangeably and are defined as the gas flow rate divided by
the surface area of the cloth.
"This verification statement was originally written for a GORE-TEX product name. GORE® is the new product
name for GORE-TEX and PRISTYNE® Filter Media Type 6250 was added as it uses the exact same L3650 fabric.
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W. L. Gore & Associates, Inc.L3650
W.L. Gore
PC# L3650
Gore-Tex/Fiberglass
Figure 1. Photograph of W. L. Gore & Associates, Inc.'s L3650 filter fabric
Table 1. Test Conditions for Baghouse Filtration Products Brand/Model:
W. L. Gore & Associates, Inc.'s L3650
Test parameter
Dust concentration
Filtration velocity (G/C)
Pressure loss before cleaning
Tank pressure
Valve opening time
Air temperature
Relative humidity
Total raw gas stream flow rate
Sample gas stream flow rate
Number of filtration cycles
• During conditioning period
During recovery period
Performance test duration
Value
18.4 ± 3.6 g/dscm (8.0 ± 1.6 gr/dscf)
120 ± 6 m/h (6.6 ± 0.3 fpm)
1,000 ± 12 Pa (4 ± 0.05 in. w.g.)
0.5 ± 0.03 MPa (75 + 5 psi)
50 ± 5 ms
25 + 2 °C (78 + 4 °F)
50 ± 10 %
5.8±0.3m3/h(3.4±0.2cfm)
1. 13 ± 0.06 m3/h (0.67 ± 0.03 cfm)
10,000 cycles
30 cycles
6h± Is
111
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W. L. Gore & Associates, Inc.L3650
Table 2. Baghouse Filtration Product Three-run Average Test
Results for W. L. Gore & Associates, Inc.'s Fabric L3650
Verification parameter
Outlet particle concentration at standard conditions3
PM2 5, g/dscm
(gr/dscf)
Total mass, g/dscmb
(gr/dscf)
Average residual pressure drop, cm w.g. (in. w.g.)
Initial residual pressure drop, cm w.g. (in. w.g.)
Residual pressure drop increase, cm w.g. (in. w.g.)
Filtration cycle time, s
Mass gain of test sample filter, g (gr)
Number of cleaning cycles
At verification test
conditions
<0.000002
(<0.000007)
<0.000002
(<0.000007)
2.45 (0.96)
2.36(0.93)
0.18(0.07)
251
0.09(1.39)
87
NA = Not applicable - values shown are for three tests.
a Standard conditions: 101.3 kPa (14.7 psia) and 20 °C (68 °F). One or more of the impactor substrate weight
changes for these results were near the reproducibility of the balance.
b Total mass includes the mass of PM2 5 and larger particles that passed through the fabric.
The APCT Verification Center quality assurance officer has reviewed the test results and the quality
control data and has concluded that the data quality objectives given in the generic verification protocol
and test/QA plan have been attained.
This verification statement addresses five aspects of filter fabric performance: filter outlet PM2 5
concentration, filter outlet total mass concentration, pressure drop (AP), filtration cycle time, and mass
gain on the filter fabric. Users may wish to consider other performance parameters such as temperature,
service life, and cost when selecting a filter fabric for their application.
In accordance with the generic verification protocol, this verification statement is applicable to filter
media manufactured between the signature date of the verification statement and 3 years thereafter.
IV
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W. L. Gore & Associates, Inc.L3650
signed by Sally Gutierrez 7/28/06 signed by Andrew R. Trenholm 7/20/06
Sally Gutierrez Date Andrew R. Trenholm Date
Director Director
National Risk Management Research Laboratory APCT Verification Center
Office of Research and Development RTI International
United States Environmental Protection Agency
NOTICE: ETV verifications are based on an evaluation of technology performance under specific, predetermined
criteria and the appropriate quality assurance procedures. EPA and RTI make no express or implied warranties as to
the performance of the technology and do not certify that a technology will always operate as verified. The end user
is solely responsible for complying with any and all applicable federal, state, and local requirements. Mention of
commercial product names does not imply endorsement.
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W. L. Gore & Associates, Inc.L3650
Environmental Technology
Verification Report
Baghouse Filtration Products
W. L. Gore & Associates, Inc.
L3650 Filter Sample
Prepared by
RTI International
ETS, Incorporated
EPA Cooperative Agreement CR 83191101-1
EPA Project Manager
Michael Kosusko
Air Pollution Prevention and Control Division
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
July 2006
VI
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W. L. Gore & Associates, Inc.L3650
Notice
This document was prepared by RTI International (RTI) and its subcontractor ETS, Inc. (ETS) with
partial funding from Cooperative Agreement No. CR 83191101-1 with the U.S. Environmental Protection
Agency (EPA). The document has been subjected to RTI/EPA's peer and administrative reviews and has
been approved for publication. Mention of corporation names, trade names, or commercial products does
not constitute endorsement or recommendation for use of specific products.
RTI International is a trade name of Research Triangle Institute.
vn
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W. L. Gore & Associates, Inc.L3560
Foreword
The Environmental Technology Verification (ETV) Program, established by the U.S. Environmental
Protection Agency (EPA), is designed to accelerate the development and commercialization of new or
improved technologies through third-party verification and reporting of performance. The goal of the
ETV Program is to verify the performance of commercially ready environmental technologies through the
evaluation of objective and quality-assured data so that potential purchasers and permitters are provided
with an independent and credible assessment of the technology that they are buying or permitting.
The Air Pollution Control Technology (APCT) Verification Center is part of the EPA's ETV Program
and is operated as a partnership between RTI International (RTI) and EPA. The center verifies the
performance of commercially ready air pollution control technologies. Verification tests use approved
protocols, and verified performance is reported in verification statements signed by EPA and RTI
officials. RTI contracts with ETS, Inc. (ETS) to perform verification tests on baghouse filtration
products, including filter media.
Baghouses are air pollution control devices used to control particulate emissions from stationary sources
and are among the technologies evaluated by the APCT Center. The APCT Center developed (and EPA
approved) the Generic Verification Protocol for Baghouse Filtration Products to provide guidance on
these verification tests.
The following report reviews the performance of W.L. Gore & Associates Inc.'s L3560. ETV testing of
this technology was conducted during October 2005 at ETS. All testing was performed in accordance
with an approved test/QA plan that implements the requirements of the generic verification protocol at the
test laboratory.
Vlll
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W. L. Gore & Associates, Inc.L3560
Availability of Verification Statement and Report
Copies of this verification report are available from:
RTI International
Engineering and Technology Unit
P.O. Box 12194
Research Triangle Park, NC 27709-2194
U.S. Environmental Protection Agency
Air Pollution Prevention and Control Division (E343-02)
109 T. W. Alexander Drive
Research Triangle Park, NC 27711
Web Sites:
http://www.epa.gov/etv/verifications/verification-index.html (electronic copy)
http://etv.rti.org/apct/index.html
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W. L. Gore & Associates, Inc.L3560
Table of Contents
Page
ETV Joint Verification Statement i
Notice vii
Foreword viii
Availability of Verification Statement and Report ix
List of Figures xi
List of Tables xi
List of Abbreviations and Acronyms xii
Acknowledgments xiv
Section 1. Introduction 1
Section 2. Verification Test Description 1
2.1. Description of the Test Rig and Methodology 2
2.2. Selection of Filtration Sample for Testing 3
2.3. Control Tests 3
2.4. Analysis 4
Section 3. Description of Filter Fabric 7
Section 4. Verification of Performance 7
4.1. Quality Assurance 7
4.2. Results 7
4.3. Limitations and Applications 9
Section 5. References 9
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W. L. Gore & Associates, Inc.L3560
List of Figures
Page
Figure 1. Diagram of FEMAtest apparatus 6
List of Tables
Table 1. Summary of Control Test Results 4
Table 2. Summary of Verification Results For W. L. Gore & Assoc., Inc.'s Fabric L3560 8
XI
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W. L. Gore & Associates, Inc.L3560
List of Abbreviations and Acronyms
APCT Air Pollution Control Technology
APPCD Air Pollution Prevention and Control Division
BFP baghouse filtration product
cfm cubic feet per minute
cm centimeters
cm w.g. centimeters of water gauge
dia. diameter
AP pressure drop
DQO data quality objective
dscm/h dry standard cubic meters per hour
EPA U.S. Environmental Protection Agency
ETS ETS, Incorporated
ETV Environmental Technology Verification
FEMA Filtration Efficiency Media Analyzer
fprn feet per minute
ft3 cubic feet
g grams
G/C gas-to-cloth ratio (filtration velocity)
gr grains
gr/dscf grains per dry standard cubic foot
g/dscm grams per dry standard cubic meter
g/h grams per hour
g/m2 grams per square meter
hr hours
in. inches
in. w.g. inches of water gauge
kg/m2 kilograms per square meter
kPa kilopascals
m meters
mbar millibars
min minutes
m/h meters per hour
xn
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W. L. Gore & Associates, Inc.L3560
m3/h cubic meters per hour
mm millimeters
MPa megapascals
ms milliseconds
NA not applicable
oz/yd2 ounces per square yard
Pa pascals
PM particulate matter
PM2 5 particulate matter 2.5 micrometers in aerodynamic diameter or smaller
psi pounds per square inch
psia pounds per square inch absolute
PTFE polytetrafluoroethylene
QA quality assurance
QC quality control
RTI RTI International
s seconds
scf standard cubic feet
scfm standard cubic feet per minute
VDI Verein Deutscher Ingenieure
w.g. water gauge
ug micrograms
urn micrometers
°C degrees Celsius
°F degrees Fahrenheit
°R degrees Rankin
Xlll
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W. L. Gore & Associates, Inc.L3560
Acknowledgments
The authors acknowledge the support of all those who helped plan and conduct the verification activities.
In particular, we would like to thank Michael Kosusko, EPA's Project Manager, and Paul Groff, EPA's
Quality Assurance Manager, both of EPA's National Risk Management Research Laboratory in Research
Triangle Park, NC. Finally, we would like to acknowledge the assistance and participation of W. L. Gore
& Associates, Inc. personnel who supported the test effort.
For more information on W. L. Gore & Associates Fiberglass Laminates, contact:
Karen McLoughlin
W. L. Gore & Associates, Inc.
101 Lewisville Road
Elkton, MD 21922
(410) 392-3300
kmclough(g),wlgore .com
or
Chris Polizzi
W. L. Gore & Associates, Inc.
101 Lewisville Road
Elkton, MD 21922
(410) 392-3300
cpolizzi@wlgore .com
For more information on verification testing of baghouse filtration products, contact:
Andrew Trenholm
RTI International
P.O. Box 12194
Research Triangle Park, NC 27709-2194
(919)316-3742
atrenholm(g),rti .org
xiv
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W. L. Gore & Associates, Inc.L3560
SECTION 1
INTRODUCTION
This report reviews the filtration and pressure drop (AP) performance of W.L. Gore & Associates Inc.'s
L3560. Environmental Technology Verification (ETV) testing of this technology/product was conducted
during a series of tests in October, 2005, by ETS, Inc. (ETS), under contract with the Air Pollution
Control Technology (APCT) Verification Center. The objective of the APCT Center and the ETV
Program is to verify, with high data quality, the performance of air pollution control technologies. Control
of fine particle emissions from various industrial and electric utility sources employing baghouse control
technology is within the scope of the APCT Center. An APCT Center program area was designed by RTI
International (RTI) and a technical panel of experts to evaluate the performance of particulate filters for
fine particle (PM2 5) emission control. Based on the activities of this technical panel, the Generic
Verification Protocol for Baghouse Filtration Products was developed. This protocol was chosen as the
best guide to verify the filtration performance of baghouse filtration products (BFPs). The specific
test/quality assurance (QA) plan for the ETV test of the technology was developed and approved in May
2000. The goal of the test was to measure filtration performance of both PM25 and total PM as well as the
pressure drop characteristics of the W.L. Gore & Associates, Inc. technology identified above.
Section 2 documents the procedures and methods used for the test and the conditions over which the test
was conducted. A description of the W. L. Gore & Associates, Inc.'s L3560 technology is presented in
Section 3. The results of the test are summarized and discussed in Section 4, and references are presented
in Section 5.
This report contains summary information and data from the test as well as the verification statement.
Complete documentation of the test results is provided in a separate data package and audit of data quality
report. These reports include the raw test data from product testing and supplemental testing, equipment
calibrations results, and QA and quality control (QC) activities and results. Complete documentation of
QA/QC activities and results, raw test data, and equipment calibrations results are retained in ETS's files
for 7 years.
SECTION 2
VERIFICATION TEST DESCRIPTION
The baghouse filtration products were tested in accordance with the APCT Center Generic Verification
Protocol for Baghouse Filtration Products1 and the Test/QA Plan for the Verification Testing of
Baghouse Filtration Products2 This protocol incorporated all requirements for quality management, QA,
procedures for product selection, auditing of the test laboratories, and reporting format. The Generic
Verification Protocol (GVP) describes the overall procedures to be used for verification testing and
defines the data quality objectives. The values for inlet dust concentration, raw gas flow rate, and
filtration velocity used for current verification testing were revised in consultation with the technical
panel since posting of the GVP. These revisions are documented in Section 4.1. The test/QA plan details
how the test laboratory at ETS will implement and meet the requirements of the GVP.
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W. L. Gore & Associates, Inc.L3560
2.1 DESCRIPTION OF THE TEST RIG AND METHODOLOGY
The tests were conducted in ETS's Filtration Efficiency Media Analyzer (FEMA) test apparatus
(Figure 1). The test apparatus consists of a brush-type dust feeder that disperses test dust into a vertical
rectangular duct (raw-gas channel). The dust feed rate is continuously measured and recorded via an
electronic scale located beneath the dust feed mechanism. The scale has a continuous read-out with a
resolution of 10 g. A radioactive polonium-210 alpha source is used to neutralize the dust electrically
before its entry into the raw-gas channel. An optical photo sensor monitors the concentration of dust and
ensures that the flow is stable for the entire duration of the test. The optical photo sensor does not
measure concentration. A portion of the gas flow is extracted from the raw-gas channel through the test
filter, which is mounted vertically at the entrance to a horizontal duct (clean-gas channel). The clean-gas
channel flow is separated in two gas streams, a sample stream and a bypass stream. An aerodynamic "Y"
is used for this purpose. The aerodynamic "Y" is designed for isokinetic separation of the clean gas with
40 percent of the clean gas entering the sample-gas channel without change in gas velocity. The sample-
gas channel contains an Andersen impactor for particle separation and measurement. The bypass channel
contains an absolute filter. The flow within the two segments of the "Y" is continuously monitored and
maintained at selected rates by adjustable valves. Two vacuum pumps maintain air flow through the raw-
gas and clean-gas channels. The flow rates, and thus the gas-to-cloth ratio (G/C) through the test filter,
are kept constant and measured using mass flow controllers. A pressure transducer is used to measure the
average residual pressure drop of the filter sample. The pressure transducer measures the differential
pressure across the filter samples 3 seconds after the cleaning pulse. The pressure drop measurements are
then averaged as described in Appendix C, Section 4.4.1 of the GVP.1 High-efficiency filters are installed
upstream of the flow controllers and pumps to prevent contamination or damage caused by the dust. The
cleaning system consists of a compressed-air tank set at 0.5 MPa (75 psi), a quick-action diaphragm
valve, and a blow tube [25.4mm (1.0 in.) dia.] with a nozzle [3 mm (0.12 in.) dia.] facing the downstream
side of the test filter.
Mean outlet particle concentration is determined when a portion of the gas flow is extracted from the raw-
gas channel through the test filter, which is mounted vertically at the entrance to a horizontal duct (clean-
gas channel). The clean-gas flow is separated using an aerodynamic "Y" so that a representative sample
of the clean gas flows through an Andersen impactor that determines the outlet particle concentration.
The particle size was measured while a fine dust was injected into the air stream upstream of the filter
fabric sample.
The following series of tests was performed on three separate, randomly selected filter fabric samples:
• Conditioning period,
• Recovery period, and
• Performance test period.
To simulate long-term operation, the test filter was first subjected to a conditioning period, which consists
of 10,000 rapid pulse cleaning cycles under continuous dust loading. During this period, the time
between cleaning pulses is maintained at 3 seconds. No filter performance parameters are measured in
this period.
The conditioning period is immediately followed by a recovery period, which allows the test filter fabric
to recover from rapid pulsing. The recovery period consists of 30 normal filtration cycles under
continuous and constant dust loading. During a normal filtration cycle, the dust cake is allowed to form
on the test filter until a differential pressure of 1,000 Pa (4.0 in. w.g.) is reached. At this point the test
filter is cleaned by a pulse of compressed air from the clean-gas side of the fabric. The next filtration
cycle begins immediately after the cleaning is complete.
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W. L. Gore & Associates, Inc.L3560
Performance testing occurs for a 6-hour period immediately following the recovery period (a cumulative
total of 10,030 filtration cycles after the test filter has been installed in the test apparatus). During the
performance test period, normal filtration cycles are maintained and, as in the case of the conditioning and
recovery periods, the test filter is subjected to continuous and constant dust loading.
The filtration velocity (G/C) and inlet dust concentrations are maintained at 120 ± 6 m/h (6.6 ± 0.3 fpm)
and 18.4 ±3.6 g/dscm (8.0 ±1.6 gr/dscf), respectively, throughout all phases of the test.
2.2 SELECTION OF FILTRATION SAMPLE FOR TESTING
Filter fabric samples of L3560 were supplied to ETS directly from the manufacturer (W. L. Gore &
Associates, Inc.) with a letter signed by Dick Winkelmayer, Business Leader for Industrial Dry Filtration,
W. L. Gore & Associates, Inc., attesting that the filter media were selected at random in an unbiased
manner from commercial-grade media and were not treated in any manner different from the media
provided to customers. The manufacturer supplied the test laboratory with nine 46 x 91 cm (18 x 36 in.)
filter samples. The test laboratory randomly selected three samples and prepared them for testing by
cutting one test specimen of 150 mm (5.9 in.) diameter from each selected sample for insertion in the test
rig sample holder. The sample holder has an opening 140 mm (5.5 in.) in diameter, which is the
dimension used to calculate the face area of the tested specimen.
2.3 CONTROL TESTS
Two types of control tests were performed during the verification test series. The first was a dust
characterization, which is performed monthly. The reference dust used during the verification tests was
Pural NF aluminum oxide dust. The Pural NF dust was oven dried for 2 hours and sealed in an airtight
container prior to its insertion into the FEMA apparatus. The dust characterization results had to meet the
requirements of a 1.5 um maximum mass mean diameter and between 40 and 90 percent less than 2.5 um
to continue the verification test series.
The second control test, the reference value test, is performed quarterly using the reference fabric and the
FEMA apparatus. The reference value test determines the weight gain of the reference fabric as well as
the maximum pressure drop. The results of the test verify that the FEMA apparatus is operating
consistently within the required parameters. Reference values tests are conducted and the average fabric
maximum pressure drop and fabric weight gain must meet criteria in the revised test/QA plan.
The results of the control tests are summarized in Table 1.
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W. L. Gore & Associates, Inc.L3560
Table 1. Summary of Control Test Results
Mass mean diameter, um
% Less than 2.5 um
Weight gain, g
Maximum AP, cm w.g.
Requirement
<1.5
40 - 90%
1.19 ±40%
0.67 ± 40%
Measured value
1.30
73.63
0.85
0.48
Met requirements?
Yes
Yes
Yes
Yes
AP = pressure drop.
Three reference value control test runs were conducted.
2.4 ANALYSIS
The equations used for verification analysis are described below.
Af = Exposed area of sample filter, m2
Cds = Dry standard outlet particulate concentration of total mass, g/dscm
C2.5ds = Dry standard outlet particulate concentration of PM2 5, g/dscm
d = Diameter of exposed area of sample filter, m
Fa = Dust feed concentration corrected for actual conditions, g/m3
Fs = Dust feed concentration corrected for standard conditions, g/dscm
G/C = Gas-to-cloth ratio, m/h
Mt = Total mass gain from Andersen impactor, g
M2 5 = Total mass gain of particles equal to or less than 2.5 urn diameter from Andersen impactor, g.
This value may need to be linearly interpolated from test data.
N = Number of filtration cycles in a given performance test period
Pavg = Average residual pressure drop, cm w.g.
Pj = Residual pressure drop for ith filtration cycle, cm w.g.
Ps = Absolute gas pressure as measured in the raw-gas channel, mbar
Qa = Actual gas flow rate, m3/h
Qds = Dry standard gas flow rate, dscm/h
Q2.sds = Dry standard gas flow rate for 2.5 urn particles, dscm/h
Qst = Standard gas flow rate for a specific averaging time, t, dscm/h
t = Specified averaging time or sampling time, s
tc = Average filtration cycle time, s
Ts = Raw-gas channel temperature, °F
wf = Weight of dust in feed hopper following specified time, g. Because of vibrations causing
short-term fluctuations to the feed hopper, it is recommended that this value be measured as a
1-min average.
w; = Weight of dust in feed hopper at the beginning of the specified time, g. Because of vibrations
causing short-term fluctuations to the feed hopper, it is recommended that this value be
measured as a 1-min average.
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W. L. Gore & Associates, Inc.L3560
Conversion factors and standard values used in the equations are listed below.
460 = 0 °F, in °R
1,013 = Standard atmospheric pressure, mbar
528 = Standard temperature, °R
Area of Sample Fabric - Af
Af=(:r-d2)/4
Actual Gas Flow Rate - Qa
Qa = Qds • rrr. +460)-ion 1
L PS • 528 J
Gas-to-Cloth Ratio - G/C
G/C = Qa/Af
Standard Dust Feed Concentration - Fs, for a specified time -1
F, = (wi-Wf)/(Qst-t)
Actual Raw Gas Dust Concentration - Fa
F. = F.-rrr,. +460)-10131
L PS' 528 J
Dry Standard Clean Gas Particulate Concentration, Total Mass - Cds
Cds = Mt / [ Qds • t • (1 - %H2O/100) ]
Dry Standard Clean Gas Particulate Concentration, PM2 5 - C2.5ds
C2.5ds = M2 5 / [ Q2.5ds • t • (1 - %H2O/100) ]
Filtration Cycle Time - tc
tc = t/N
Average Residual Pressure Drop - Pavg
Pavg
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W. L. Gore & Associates, Inc.L3560
DUST FEED FROM EXTERNAL HOPPER
DUST CHARGE NEUTRALIZER
RECTANGULAR CHANNEL
111 x 292 mm (4-3/8 x 11-1/2")
PHOTOMETER
FILTER FIXTURE AND TEST FILTER
CYLINDRICAL EXTRACTION TUBE
CLEAN-GAS SAMPLE PORT
RAW-GAS SAMPLE PORT
CLEANING SYSTEM
BACKUP
FILTER
MASS FLOW
CONTROLLER
ABSOLUTE FILTER AND
ANDERSENIMPACTOR
MASS FLOW
CONTROLLER
Figure 1. Diagram of FEMA test apparatus
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W. L. Gore & Associates, Inc.L3560
SECTION 3
DESCRIPTION OF FILTER FABRIC
The L3560 is a membrane/fiberglass fabric laminate with a weight of 22 oz/yd2 (746 g/m2) and used in
both GORE® Filtration Products and PPJSTYNE® Filter Media Type 6250*.
SECTION 4
VERIFICATION OF PERFORMANCE
4.1 QUALITY ASSURANCE
The EPA quality assurance manager conducted an independent assessment of the test laboratory in June
2005, and found that the test laboratory was equipped and operated as specified in the test/QA plan.
The ETS QA officer and APCT Center QA staff have reviewed the results of this test and have found that
the results meet data quality objectives as stated in the revised test/QA plan. It should be noted that,
because of the highly efficient nature of the filter medium being tested, the impactor substrate weighings
for these results were below the reproducibility of the balance. As a result of this occurrence, the tests do
not meet the data quality objectives (DQOs) stated in the test/QA plan for mass gain associated with
outlet concentrations. Nevertheless, the data were judged usable for their intended purpose. Data on
calibration certificates for the flow meters, flow transducers, weights, low- and high-resolution balances,
thermometer, and humidity logger are maintained at ETS in a separate data package.
The verification tests were conducted in accordance with an approved test/QA plan.2 Deviations from the
test plan include organizational personnel changes, corrections to DQO and specification tables to match
the GVP approved in October 2001, plus associated revisions. Updates of values to match protocol
values include changing the filtration velocity to 120 m/hr, dust feed operation to 100 g/hr, inlet dust
concentration to 18.4 g/dscm, mass mean aerodynamic diameter of the dust to 1.5 um ± 1 urn, and particle
size of the dust to 40-90% as specified in the approved 2001 GVP.
The ETS QA officer and APCT Center QA staff have also reviewed the results of the control tests, which
are summarized in Section 2.3, Table 1. The dust characterization control test met the appropriate
requirements of the test/QA plan and verification protocol. Reference fabric tests meet revised maximum
pressure drop and weight gain requirements established for reference fabric performance in the GVP,
indicating the measurement system is operating in control.
4.2 RESULTS
Table 2 summarizes the mean outlet particle concentration measurements for the verification test periods.
Measurements were conducted during the 6-hour performance test period. The performance test period
followed a 10,000-cycle conditioning period and a 30-cycle recovery period.
The top portion of Table 2 summarizes three verification tests that were performed under standard
verification test conditions. The average residual AP across each filter sample at the nominal 120 m/h
This verification statement was originally written for a GORE-TEX product name. GORE" is the new product
name for GORE-TEX and PRISTYNE® Filter Media Type 6250 was added as it uses the exact same L3650 fabric.
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W. L. Gore & Associates, Inc.L3560
(6.6 rpm) filtration velocity [for a flow rate of 5.8 m3/h (3.4 cfm)] is also shown in Table 2. This AP
ranged from 2.37 to 2.54 cm w.g. (0.93 to 1.00 in. w.g.) for the three filter samples tested. The residual
AP increase ranged from 0.14 to 0.21 cm w.g. (0.06 to 0.08 in. w.g.) for the samples tested. All three
standard condition verification runs were used to compute the averages given in Table 2. The PM2 5
concentration average for the three runs is <0.000002 g/dscm. The total PM concentration average for the
three runs is <0.000002 g/dscm.
Table 2. Summary of Verification Results For W. L. Gore & Associates, Inc.'s Fabric L3560
Test run number
PM25 (g/dscm)**
Total PM (g/dscm)
Average residual AP (cm w.g.)
Initial residual AP (cm w.g.)
Residual AP increase (cm w.g.)
Mass gain of sample filter (g)
Average filtration cycle time (s)
Number of cleaning cycles
4V2-R1
<0.000002
<0.000007
2.54
2.42
0.21
0.09
221
97
4V2-R2
<0.000002
<0.000007
2.43
2.36
0.18
0.09
241
89
4V2-R3
<0.000002
<0.000007
2.37
2.30
0.14
0.09
291
74
Average*
<0.000002
<0.000007
2.45
2.36
0.18
0.09
251
87
* All three verification runs were used to compute averages.
** The impactor substrate weight changes for these results were below the reproducibility of the balance.
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W. L. Gore & Associates, Inc.L3560
4.3 LIMITATIONS AND APPLICATIONS
This verification statement addresses five aspects of filter fabric performance: filter outlet PM2 5
concentration, filter outlet total mass concentration, pressure drop (AP), filtration cycle time, and mass
gain on the filter fabric. Users may wish to consider other performance parameters such as temperature,
service life, and cost when selecting a filter fabric for their application.
In accordance with the GVP, this verification statement is applicable to baghouse filtration products
manufactured between signature date of the verification statement and 3 years thereafter.
SECTION 5
REFERENCES
1. Generic Verification Protocol for Baghouse Filtration Products, RTI International, Research
Triangle Park, NC, February 2000. Available at http://etv.rti.org/apct/pdf/baghouseprotocol.pdf
2. Test/QA Plan for the Verification Testing of Baghouse Filtration Products, ETS, Inc., Roanoke,
VA, February 1999.
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