United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/4-91-020a
August 1991
Air
The Measurement Solution:
Using a Temporary Total
Enclosure for Capture
Efficiency Testing
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THE MEASUREMENT SOLUTION
Using a Temporary Total Enclosure
for Capture Efficiency Testing
EPA Contract No. 68-DO-0137
Work Assignment 69
ESD Project No. 89/07
MRI Project No. 9800-69
Prepared for:
Karen Catlett
Chemicals and Petroleum Branch
Emission Standards Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
Prepared by:
Stephen W. Edgenon
Joanne Kempen
Thomas W. Lapp
Midwest Research Institute
401 Harrison Oaks Boulevard, Suite 350
Gary, North Carolina 27513
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DISCLAIMER
This report has been reviewed by the Emission Standards Division
of the Office of Air Quality Planning and Standards, EPA, and
approved for publication. Mention of trade names or commercial
products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available -
as supplies permit - through the Library Services Office (MD-35),
U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, or, for a nominal fee, from National
Technical Information Services, 5285 Port Royal Road,
Springfield, Virginia 22161.
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TABLE OF CONTENTS
PAGE
CHAPTER 1. INTRODUCTION 1
PURPOSE 1
BACKGROUND 1
ORGANIZATION 2
CHAPTER 2. WHAT IS CAPTURE EFFICIENCY? 3
CHAPTER 3. WHY MEASURE CAPTURE EFFICIENCY? 7
CHAPTER 4. WHAT IS A TOTAL ENCLOSURE? II
WHAT IS A TEMPORARY TOTAL ENCLOSURE? 11
WHAT IS A PERMANENT TOTAL ENCLOSURE? 14
CHAPTER 5. HOW TO DESIGN AND CONSTRUCT A TEMPORARY
TOTAL ENCLOSURE 17
DESIGN 17
The Plant Visit 18
After The Plant Visit 20
Construction Materials 25
CONSTRUCTION 27
CHAPTER 6. WHAT TESTS ARE REQUIRED? 37
AVERAGE FACE VELOCITY TEST 37
PERFORMANCE TESTS FOR CAPTURE EFFICIENCY 39
Fugitive VOC Emissions 40
Captured VOC Emissions 41
Background Tests 41
Applicable EPA Methods 41
APPENDIX A. EXAMPLE CALCULATIONS
A-l. . Average Face Velocity A-l
A-2. VOC Concentration of Fugitive Emissions
at Each Sampling Site A-4
A-3. Total VOC Fugitive Emissions A-5
VOC Concentration of Captured Emissions
at Each Sampling Site
in
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TABLE OF CONTENTS (continued)
PAGE
A-5. Total VOC Captured Emissions A-7
A-6. Background VOC Concentrations at Each
Sampling Site A-8
A-7. Average Background Concentration A-9
A-8. Capture Efficiency A-ll
APPENDIX B. TEST METHODS
Method 204 Criteria for and Verification of a Permanent
or Temporary Total Enclosure B-l
Method 204B Volatile Organic Compound Emissions in
Captured Stream B-5
Method 204C Volatile Organic Compound Emissions in Captured Stream
(Dilution Technique) B-15
Method 204D Volatile Organic Compound Emissions in Fugitive Stream from
Temporary Total Enclosure B-27
APPENDIX C. SAFETY AND HEALTH CONSIDERATIONS
WORKER HEALTH PROTECTION C-l
Allowable Exposure Levels C-l
Sizing the Temporary Exhaust System C-2
Monitoring Considerations for Heath Protection C-13
FIRE SAFETY C-24
Allowable VOC Levels C-24
Sizing the Temporary Exhaust System C-25
Monitoring Considerations for Fire Safety C-30
REFERENCES FOR APPENDIX C C-31
APPENDIX D. TEMPORARY TOTAL ENCLOSURE DESIGN CASE STUDY
GLOSSARY OF TERMS
IV
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LIST OF FIGURES
PAGE
Figure 2-1. Simplified process/emissions diagram 3
Figure 3-1. The components of control system efficiency 8
Figure 3-2. Control system efficiency with a permanent total
enclosure 9
Figure 3-3. Control system efficiency with a solvent recovery
device 10
Figure 4-1. The criteria for a TTE 12
Figure 4-2. The criteria for a PTE 15
Figure 6-1. The average face velocity test 38
Figure 6-2. The capture efficiency performance test 39
LIST OF TABLES
PAGE
TABLE M. EXAMPLES OF COMMON CHEMICALS REGULATED AS
VOC'S 4
TABLE 2-2. ORGANIC COMPOUNDS EXEMPTED AS VOC'S 4
TABLE 5-1. SAMPLE ADVANCE QUESTIONNAIRE 30
TABLE 5-2. SAMPLE CAPTURE EFFICIENCY PRETEST SITE VISIT
CHECKLIST 33
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PAGE 1
CHAPTER 1
INTRODUCTION
PURPOSE
This document presents an overview of
the gas/gas temporary total enclosure (TIE)
method for measuring capture efficiency (CE).
Information is also provided on the criteria for
a permanent total enclosure (PTE) to aid in
evaluating the necessity of testing for CE. The
document is intended for use by State and local
agency personnel who will oversee the CE
testing procedures or by the facility personnel
and their test contractors who will construct the
TTE and perform all of the required test
protocols. The procedures outlined in the
following sections of this document are
intended to present a straightforward approach
to CE testing using a TTE.
This guidance document was prepared
based on the U. S. Environmental Protection
Agency's (EPA's) CE measurement
procedures. The States arc expected to adopt
compatible measurement procedures; however.
the reader should verify that the planned
approach is consistent with State procedures.
BACKGROUND
Persistent ozone problems in many areas
of the United States have focused attention on
reducing volatile organic compound (VOO
emissions. Early efforts resulted in reductions
in VOC emissions from sources that are
relatively easy to control. However, the need
for additional reductions has brought about
increased attention to more difficult VOC
control problems. With this attention has come
an increased emphasis on maximizing, and
measuring, CE. For example, EPA has
promulgated five new source performance
standards that include variations of the gas/gas
TTE measurement procedure (40 CFR 60
Subparts RR, TT, FFF, SSS, and VVV).
In April 1990, EPA issued guidance on
CE measurement procedures, emphasizing
procedures that require a total enclosure. Such
methods are preferred because the estimated
probable error is lower for these methods than
for others. The EPA intends to add the CE
measurement procedures (with minor revisions)
to 40 CFR 51, Appendix M, as test methods.
There arc two types of total enclosures:
permanent and temporary. A TTE is erected
solely to test the CE of a process. After the
The Problem:
Emission
Point
Fugitive
VOCs
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PAGE 2
The Measurement Solution:
A Temporary
Total Enclosure
test is completed, the TTE is dismantled until
the next time the test must be performed. A
PTE is put in place permanently to achieve
"total" capture of the VOC emissions
continuously. If the PTE meets certain criteria
cited later in this document, EPA and the
States permit CE to be assumed to be
100 percent, and testing to determine CE is
not required. Remember that testing for the
efficiency of the control device may still be
required; only CE testing is waived.
ORGANIZATION
In Chapter 2, the definition of CE is
presented and explained. Chapter 3 discusses
the need for CE measurements. The definition
of a TTE is presented and explained in
Chapter 4. In Chapter 5, a step wise approach
to the design and construction of a TTE is
presented, and Chapter 6 discusses CE testing.
Supplemental materials are presented in the
Appendices that follow Chapter 6.
The Emission Reduction Solution:
A Permanent
Total Enclosure
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PAGE 3
CHAPTER 2
WHAT IS CAPTURE EFFICIENCY?
The formal definition for capture
efficiency (CE), as measured by the gas/gas
temporary total enclosure method, is: the
fraction of all volatile organic compounds
(VOC's) generated by and released at an
affected facility that is directed to a control
device. Perhaps this can be visualized better
by use of the simplified diagram in Figure 2-1,
Simply, the capture efficiency is the
percentage of the total VOC released by the
process that is captured and delivered to the
control device. In the sections below, we will
look at the different parts of the definition to
explain more fully what each part means.
What constitutes a VOC? A VOC is
defined as any organic compound that
participates in atmospheric photochemical
(sunlight) reactions. (A more exhaustive
definition is included in the glossary at the end
of this document.) In practical terms, this
means that VOC's include many of the
chemicals that are currently being used as
solvents and many other commonly used
liquids (or the liquid portions of mixtures).
Some specific examples of types of chemicals
that are typically VOC's are given in
Table 2-1.
The only organic compounds that are not
currently considered by EPA to be VOC's are
presented in Table 2-2. These compounds
have been exempted by EPA because of their
negligible photochemical reactivity.
FUGITIVE
EMISSIONS
(F)
TO CONTROL
(Q)
RAW MATERIALS
VOC'ft
PROCESS
PRODUCTS
Figure 2-1. Simplified process/emissions diagram.
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PAGE 4
TABLE 2-1. EXAMPLES OF COMMON CHEMICALS REGULATED AS VOC's
Class
Alcohols
Hydrocarbons-aliphatic
Hydrocarboni-aromatic
Chlorinated hydrocarbons-aliphatic
Chlorinated hydrocarbons-aromatic
Esters
Ketones
Ethers
Aldehydes
Examples
Methanol, ethanol, propyl alcohols, cyclohexanol, butyl alcohols, ethylcne
glycol, propylene glycol
Hexane. penune. cyclohexane. mineral spihu, VM&P naphtha
Benzene, toluene (toluol), ethylbenzene, xylenei (xylol)
Chloroform, ethylene dichlc ide, tetrachloroethylene (perc)
Monochlorobenzene, dichJorobenzene, thchlorobenzene
Ethyl aceute. isopropyl aceuu, butyl acetate, glycol ether acetate
Acetone, methyl ethyl ketonc, methyl isobutyl ketone, cyclohexanone, methyl
iso-amyl ketone
Ethyl ether, ethylcne glycol mono-methyl ether, diethylene glycol mono-butyl
ether, propylene glycol mono-methyl ether, tetrahydrofuran, ethylene glycol
mono-ethyl ether
Formaldehyde, acetaldehyde, benzaldehyde
TABLE 2-2. ORGANIC COMPOUNDS EXEMPTED AS VOC's
Current List
Methane
Ethane
1,1,1-Trichloroetnane (methyl chloroform)
l.l.--Trichloro-1.2,2-trifluoroeihane (CFC-1 13)
Dichloromethane (methyiene chlonoei
Trichloronuoromethane (CFC-1 11
Dichlorodifluoromethuie (CFC-12)
Chlorodifluoromeihane (CFC-22)
Trifluoromethane (FC-23;
l,2-Dichloro-l,l,2,2-letranuoroeth«ne (CFC-1 K)
Chloropentafluoroethane (CFC-1 15)
l.l-Dtchloro^^.^rifluoroethanc (HCFC-1^)
1 , 1 ,1 .2-Tetrafluoroethane (FC- 134a)
1 . 1 -Dichloro- 1 -fluoroethane (HCFC- 1 4 1 b )
l-Chloro-l,l-difluoroethane(HCFC-142t)i
Proposed Additions1
2-Chloro-l,1.1.2-ietrafluoroethane(HCFC-124)
Penunuoroethane (HFC-125)
1 , 1 .:,2-Tetrafluoroeihane (HFC-134)
1,1,1-Trifluoroethane (HFC-143a)
1,1-Diftuoroethane (HFC-1S2&)
CvcLc, branched, or linear, completely fluonntied alkanes
Cyclic, branched, or linear, completely fluonnated ethers
with no unsaturations
Cycuc, branched, or linear, completely fluonnated tertiary
amines with no unsaturations
Sulfur-conutning perfluorocarbons with no unsaturations and
with sulfur bonds onlv to carbon and fluorine
i!
•Proposed in Federal Register (56 FR 11387, Marcfi 18, 19911; final action expected in 1991.
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PAGES
What is an affected facility? An
affected facility is the equipment or process to
which the regulation applies and which must
be tested for VOC capture efficiency. An
example of an affected facility is a coil coating
line or a flexographic press.
What does "VOC's generated by and
released at" mean? This phrase means the
VOC's that are released by the process as a
gas in the immediate vicinity of the process.
The VOC's generally enter the process as a
component of the raw materials and are
usually liquid. During the process, some or
all of the VOC's evaporate due to heat or
other causes. This CE procedure measures
only the VOC's released in the gas phase in
the vicinity of the process being tested. In
cases where emissions outside the affected
facility are covered by the applicable
regulations, these emissions must be evaluated
by some other means. Examples of such
emissions include the gradual release of
retained solvent from a product after it has left
the manufacturing area and the evaporation of
VOC's from waste coatings or inks during
storage and disposal.
What does "directed to a control
device" mean? The VOC's directed to a
control device are those that are contained in
or drawn into a capture device and vented to a
control device. A capture device may be a
drying oven, enclosed room, hood, floor
sweep, or other means of containing or
collecting VOC's and directing those VOC's
into a duct.
In contrast to the "captured" emissions,
which are directed to a control device, other
VOC's are emitted into the ambient air of the
plant (see Figure 2-1). These emissions may
diffuse through the plant but eventually reach
the atmosphere through the general ventilation
system or open windows or doors. These are
considered "fugitive" emissions.
Actually, at some facilities there may be
emissions that are collected by a capture
device and vented directly to the atmosphere
through a stack or duct. Although these
emissions are not typically considered fugitive
emissions, within the context of this
document all emissions that are not directed
to a control device are considered fugitive
emissions for the purpose of the calculations
to be performed.
What is a control device? A control
device is any equipment that reduces the
quantity of VOC that is emitted to the
atmosphere. Examples of control devices are
incinerators, carbon adsorbers, and
condensers.
How is CE determined? In theory,
determining capture efficiency is a very simple
and straightforward process. In short, the
quantity of VOC directed to the control device
divided by the total quantity of VOC released
by the process (i.e., the quantity vented to the
control device plus the quantity of fugitive
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PAGE 6
emissions) is the capture efficiency. This
relationship is shown by the following
equation:
G
Capture efficiency (%) = x 100
(CE) G -I- F
where:
G « quantity of VOC released by the
process that is directed to the
control device (i.e., the captured
VOC).
F = quantity of VOC released by the
process that escapes as fugitive
emissions.
G + F = total VOC's generated by and
released at the affected facility.
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PAGE 7
CHAPTERS
WHY MEASURE CAPTURE EFFICIENCY?
Most volatile organic compound (VOC)
regulations relate the allowable emissions for a
process to the amount of raw material used in
the process. Such regulations are frequently
presented in terms of an overall percent
reduction or in terms of the VOC content of
the feedstock coating or ink. Regardless of
how the standard is stated, when complying
coatings or inks are not used, compliance is
typically determined by evaluating the
percentage of the input VOC that is prevented
from reaching the atmosphere. This
percentage is called the "control system
efficiency" (CSE).
As illustrated in Figure 3-1, CSE has two
components, capture efficiency (CE) and
control device efficiency (CDE). While CDE
has often received more attention, CE is
equally important. A control device can act
upon only those VOC's that have been
captured and directed to the device. The
device cannot control VOC's that do not reach
it. For example, if only 50 percent of VOC
emissions are captured, the maximum CSE
that can be achieved is 50 percent, even with a
control device that is 100 percent efficient.
The use of improved CE measurement
protocols, such as the one presented in this
document, will allow the emphasis on CE to
equal that long placed on CDE.
Mathematically, CSE is the product of
the fractional capture and control device effi-
ciencies. The equation is:
CSE = CE x CDE
Examples of CSE calculations are:
CDE
CSE
0.50
0.75
0.90
1.00
0.95
0.90
0.95
0.95
0.48
0.68
0.86
0.95
In most cases, to determine the CSE of a
process accurately, both the CE and CDE must
be measured. However, EPA and the States
permit 100 percent capture efficiency to be
assumed without measurement if it is shown
that the process is contained in a permanent
total enclosure (PTE). No capture efficiency
testing is necessary if the process enclosure
can meet the requirements for a PTE, although
the CDE still must be measured. Figure 3-2
illustrates the use of PTE.
Another case where CE may not have to
be measured is a process that is controlled
with a solvent recovery device. If the quantity
of VOC recovered can be directly compared to
the quantity of VOC input to the process, CSE
can be determined directly without measuring
either CE or CDE. This situation is illustrated
in Figure 3-3.
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Q
oo
Fugitive
Emissions
[iolb/h7]
Process
Captured
Emissions
[DO Ib/hr]
Control Device
CE =
CDE =
90 Ib/hr
90 Ib/hr+10 Ib/hr
0.90
G-E
90 Ib/hr • 9 Ib/hr
90 Ib/hr
0.90
CSE = CE x CDE =
G-E
Control Device
Emissions
9 Ib/hr
90ihftir-9>b/nr
90 Ib/hr+10 Ib/hr:
0.81
-CE-
-CDE-
-CSE-
Figure 3-1. The componenis of control system efficiency.
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Air
Fugitive
Emissions
0 tb/hr by definition
/ VOC \
sssss^sss
%x^fc^\%^^^^
Process
*
' — Permanent Total
Enclosure
« OF
© • Control Device () — *-{E)
Captured r^n,m, n^i,.
tmissions Emissions
I00lb/hr 10lb/hr
CE^ 1.00 (by definition)
Air
^^ G-E toolbar- 10 loAtr rtrtrt
^L't " p ' irtniK/hr" u.ju
LJ i uu lo/nr
CSE -CExCDE-CDEUo90
k • PDF . . ••
\stjf-
Figure 3-2. Control system efficiency with a permanent total enclosure.
Ci
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•0
>
o
Liquid VOC
Input
lOOIh/hr
Process
-CE-
Caplured
Emissions
CE = Not Measured
CDE = Not Measured
Control Device
Mr
^^
Liquid VOC
Recovered
81lb/hr
CSE =
Sllb/hr
100lb/hr
0.81
-CSE-
-CDE-
Control Device
Emissions
3-3. Control system efficiency with a solvent recovery device.
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PAGE 11
CHAPTER 4
WHAT IS A TOTAL ENCLOSURE?
A total enclosure is a structure that
completely surrounds a process so that all
volatile organic compound (VOC) emissions
are captured for discharge through ducts or
stacks. The only openings in a toul enclosure
are forced makeup air ducts, exhaust ducts
leading to a control device or the atmosphere,
and natural draft openings (NDO's) such as
those that allow raw materials to enter and
products to leave and those that are added to
improve ventilation. It is very important that
the airflow through the total enclosure be
engineered to keep the concentration of VOC's
within the enclosure below the Occupational
Safety and Health Administration (OSHA)
health requirements and vapor explosive limits.
These two areas will be discussed in more
detail later in this chapter.
There are two types of total enclosures:
temporary and permanent. These are
discussed below.
WHAT IS A TEMPORARY TOTAL
ENCLOSURE?
A temporary total enclosure (TTE) is an
enclosure temporarily installed specifically for
the capture efficiency (CE) test. It completely
surrounds the affected facility such that all
VOC emissions are captured and discharged
through ducts that allow for the accurate
measurement of VOC rates. More simply, it
is a temporarily installed enclosure that
ensures that no VOC escapes without being
measured.
A TTE typically has two exhausts-a
permanent duct through which captured VOC's
are vented to the control device and a
temporary exhaust duct (installed for the test)
through which the VOC's normally emitted as
fugitives are vented for measurement. The
quantity of VOC passing through these ducts is
accurately measured and used to calculate the
capture efficiency. Of course, there may be
multiple ducts leading to the control device(s)
or multiple temporary exhaust ducts. Where a
TTE includes a permanent hood or other
exhaust that vents directly to the atmosphere,
the exhaust duct is considered another
temporary exhaust for purposes of measuring
and calculating fugitive emissions.
Minimum criteria have been developed
for an enclosure to be considered a TTE for
purposes of the CE test. These criteria are
intended to ensure that all VOC's are captured
for measurement and to minimize disruption of
the capture normally achieved by the existing
capture device(s) in the absence of the
enclosure. The criteria are presented below
and illustrated in Figure 4-1.
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rorrwl Mdfcm
Ait V»m ««tti (lowial*
O
rrj
Temporary EiH 200 tt/min and defnonstrabty inward.
Z. A,
Ml
Nole:00,n-Ou.Qf
Criterion 5: All acres?: (toots and windows closed rtiirinq routinn opnrntion.
I-'igurc 4 I. llie criteria Air a TTt.
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PAGE 13
1. Any NDO shall be at least 4 equivalent
opening diameters from each VOC-
emitting point. An "equivalent diameter"
is the diameter of a circle that has the
same area as the opening. The equation
for an equivalent diameter (ED) is:
0.5
ED - (4 X area)
v
For a circular NDO, this equation simply
reduces to the diameter of the opening.
2. Any exhaust point from the enclosure
shall be at least 4 equivalent duct or hood
diameters from each NDO.
3. The total area of all NDO's shall not
exceed 5 percent of the surface area of
the enclosure's walls, floor, and ceiling.
4. The average face velocity (FV) of air
through all NDO's shall be at least
200 ft/min. The direction of air through
all NDO's shall be into the enclosure.
5. All access doors and windows whose
areas are not included as NDO's and are
not included in the calculation of FV
shall be closed during routine operation
of the process.
Some terms and concepts related to
TTE's need to be explained because they are
used frequently throughout the remainder of
this document. These terms and concepts are
described in the remainder of this section and
in the glossary at the end of the Appendices.
A natural draft opening (NDO) is any
opening that remains open during routine
operation of the process and is not connected
to a duct with a fan or blower attached. Thus,
NDO's are any openings other than exhausts
(forced or induced) and forced makeup air
ducts. Examples are entrances and exits in the
enclosure to allow raw materials to enter and
products to leave. Natural draft openings that
are not related to the process also may be
added to improve the ventilation of the
enclosure. The airflow direction and rate
through the NDO depend on the difference in
pressure inside and outside of the TTE.
Face velocity is the speed of the air
flowing through the NDO. For these
procedures, the average FV is calculated by
dividing the net exhaust rate out of the
enclosure by the total area of all NDO's. The
volumetric flow rates are measured using EPA
Method 2. The equation for FV and sample
calculations are given in Appendix A-l.
Isolation of affected emissions. A CE
measurement is made as pan of a compliance
determination for a particular affected facility
or, possibly, group of affected facilities.
Thus, it is important that only emissions from
the affected facility are measured. A TTE
should enclose only emission sources that are
part of the affected facility. All other sources
should be excluded. In cases where such
isolation is not possible, determine whether the
nonaffected emissions are significant; if so,
these emissions must be accounted for in the
CE determination.
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PAGE 14
Worker safety is very important in
performing these tests. The VOC concentra-
tion within the TTE must level off at a
concentration below the OSHA Permissible
Exposure Limit (PEL) for all solvents used if
human access to the TTE is required. If no
one will enter the TTE, the allowable VOC
concentration is dictated by the lower
explosive limit (LEL). Generally the upper
limit for fire insurance purposes is 25 percent
of the LEL.
If these concentrations cannot be met,
corrective action must be taken. Corrective
actions could include repositioning the capture
devices, relocating the TTE exhaust ducts,
repositioning the NDO's, or increasing the
exhaust flow rate either to the control device
or through the temporary exhaust set up to
measure fugitive emissions. Any changes to
the permanent system components (e.g.,
capture devices, flow rates) must be
maintained after testing so that the test data
represent the situation that exists after
completion of the tests.
Monitoring the ambient VOC
concentration inside the TTE during testing to
ensure that the appropriate level is not
exceeded is strongly advised. Informaiion on
acceptable levels and monitoring considerations
for VOC mixtures is inducted in Appendix C.
WHAT IS A PERMANENT TOTAL
ENCLOSURE?
A permanent total enclosure (PTE) is an
enclosure that completely surrounds a source
of emissions such that all VOC emissions are
contained for discharge to a control device.
The enclosure must be permanent, unlike a
TTE, which is installed only for the duration
of the CE test.
The PTE must meet all of the criteria
stated for the TTE, except that there is no
restriction on the distance between exhaust
points and NDO's (see Figure 4-2). This
criteria was included for TTE's (1) to avoid
disruption of normal airflow patterns and
(2) to avoid channeling between the NDO and
the exhaust point, which could result in a VOC
buildup in other areas of the TTE. These are
of lesser concern in PTE's because in a PTE.
the airflow patterns resulting from the
interaction of the permanent NDO's and
exhausts are the "normal" patterns. In
addition, a PTE and its ventilation system are
designed to minimize problems with VOC
buildup. Any such problems within a PTE are
detected and remedied in the course of
complying with fire safety and OSHA
requirements, instead of. perhaps, being
undetected or unconnected during the
disruption of routine caused by a source test
with a TTE.
If a facility meets the criteria for a PTE
and all emissions are directed to a control
device, the CE may be assumed to be 100
percent and-THE REQUIREMENT TO
MEASURE THE CE IS WAIVED.
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PAGE 15
P*nmcn«nt
Forc*fl M*»UD
Air V*nt with Fbwrct
To Control
Owe*
Capturw) Em»ton
Slr«»m (G) with Ftowrat
Criterion 1: D, 2 4 x ED. tor every NDO and VOC source.
Criterion 2; Not applicable
Criterion3: f A,s0.05x|(2x Lx W) + (2xWxH) *<2x
Criterion 4: FV • "i . 2 200 tVmin and demonstraWy inward.
ii A|
Criterion 5: All access doors and windows dosed during routine operation.
Figure 4-2. The criteria for a PTE.
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PAGE 16
Note: An entire building can qualify as a
PTE if the building meets all of the
requirements for a PTE. A PTE can be an
entire building, one or more rooms in a
building, or a structure built around one or
more processes. However, if any of the
requirements for a PTE are not met, the
facility must undergo performance testing to
measure the CE for the affected facility.
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PAGE 17
CHAPTERS
HOW TO DESIGN AND CONSTRUCT A TEMPORARY
TOTAL ENCLOSURE
The design and construction of a
temporary total enclosure (TTE) requires
several steps to ensure that the enclosure meets
all of the requirements for valid test results.
All affected volatile organic compounds
(VOC's) (and only affected VOC's) must be
captured for measurement. In addition, the
TTE should be designed to minimize any
effect on the normal operation and perfor-
mance of the permanent capture device(s).
Another area of prime importance in designing
and building the total enclosure is the safety
and health of the workers and the test person-
nel. Health and safety concerns cannot be
overemphasized.
DESIGN
An initial stage in the design procedure is
a visit to the site of the facility to be tested.
Prior to the site visit, State agency personnel
and test contractors should prepare a list of
specific information to be sought during the
visit and send this list to the plant in advance
of the visit. This allows the plant personnel
time prior to the visit to assemble necessary
data that are not readily available. A sample
questionnaire is shown in Table 5-1 at the end
of this chapter.
General process information is needed
for each affected facility that is to be tested to
identity variables that could affect construction
and operation of the TTE. If more than one
process run is to be performed during the test,
information is needed on the most common or
longest jobs to help evaluate VOC composition
and concentration. A basic understanding of
process flow and air handling systems is
necessary to properly evaluate the facility.
Since considerable detailed knowledge is
necessary to perform these tests, the plant is
requested to provide blueprints and plans of
the plant with as much detail as possible. The
other information requested in the question-
naire will be required to evaluate the TTE
design against the criteria for the TTE.
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PAGE 18
The Plant Visit
Before visiting the plant, prepare a
checklist. A sample checklist is shown in
Table 5-2 at the end of this chapter. This
checklist emphasizes the items that must be
observed at the plant site. If possible, it helps
to have a representative of the contractor (or
plant personnel) who will construct the TTE
present during the plant visit. These personnel
may have valuable suggestions on construction
techniques or may be able to resolve some
questions about what is, or is not, practical in
constructing the TTE.
Upon arrival at the plant, meet with the
appropriate personnel to discuss the capture
efficiency (CE) protocol and the purpose of the
visit. Review the advance questionnaire for
completion and any clarifications that are
needed. Discuss any data gaps and how the
information can be obtained.
At the site of the facility, one of the first
steps is to evaluate whether the affected facilitv
is enclosed in a permanent total enclosure
(PTE), in which case a performance test to
measure CE is not necessary. The criteria for
qualification as a PTE were given in
Chapter 4. If the affected facility is not
enclosed in a PTE, either of two options can
be exercised. One option is to modify the
existing facility so it will qualify as a PTE; the
second option is to conduct performance
testing of the process to determine the CE.
which will often require construction of a
TTE.
If a TTE must be built, the VOC sources
must be surveyed to determine which of the
sources are "affected" (i.e., subject to the
emission standard) and which sources in the
immediate area are "nonaffected." The
affected sources must be included in the TTE.
and the enclosure, when constructed, must
isolate the emissions from the affected facility
from all other emissions.
During the visit, acquire the necessary
information on the checklist (Table 5-2). Be
sure to obtain the data necessary to estimate
the temporary exhaust rate needed to keep the
atmosphere inside the TTE safe and healthful
These data include information on the chemicai
composition of the VOC's to be encountered
during the test and information to estimate the
fugitive emission ra:e.
If a drying oven is pan of the process.
determine whether the oven must be encloseJ
within the TTE. If the oven contains all of the
VOC released inside it (i.e., operates at
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PAGE 19
negative pressure), the oven can function as a
component of the total enclosure for the test.
If not, the oven must be enclosed along with
the rest of the process. For the oven to
remain outside the TTE, it must be demon-
strated that air will be drawn into the oven at
all openings rather than flowing outward,
carrying VOC's with it. The oven can be
evaluated either by using a smoke tube or
plastic streamers or by performing an analysis
of the exhaust and forced makeup air volumes
as is done to evaluate face velocity (FV) across
the natural draft openings (NDO's) in the
TTE.
During the inspection of the facility, start
to visualize one or more possible TTE
configurations. As the data in the checklist are
gathered, consider their impacts on the
potential enclosure configurations. Some
important practical aspects of construction to
consider are:
* Can any existing structures (e.g., the
roof, a wall) be used as part of the
TTE?
• Will existing structures impede
construction? If so, how can they be
accommodated?
* Where are NDO's required for the
process (e.g., entrance for
continuous web)?'
» Where are doors and windows
needed?
• Will there be sufficient access for the
workers and equipment?
• Will the structure impede other
operations at the plant?
» In event of an emergency (e.g.,
fire), can personnel readily escape
the area?
• How can the temporary exhaust be
constructed? Can it be vented
outdoors through accessible
windows or roof or wall vents? If
not, where can it be exhausted
indoors? Where can the fan and
ductwork be located?
* In the TTE area, note exhaust
points, any forced makeup air
outlets, existing windows and vents.
etc. that serve the entire facility.
How can they be accommodated by
the TTE?
Check the existing duct work to the
control device, other exhausts, and any forced
makeup air ducts to ensure that EPA Method 2
testing can be performed. All exhausts from
and forced makeup air to the TTE must be
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PAGE 20
measured to verify that the minimum average
FV across the NDO's (200 ft/min) is achieved.
Before leaving the area, pick one or more
potential TTE configurations and obtain
sufficient data to evaluate them against the
TTE criteria. Included in these data
requirements are:
* Location and size of NDO's essential
to the process
* Other desirable NDO locations and
sizes in order to provide good air
movement through the TTE and
maintain constant air concentrations
at health-protective levels
• Distances from NDO's to VOC
sources
* Size of exhausts (including temporary
exhaust to be installed specifically
for the tests) and distances from
NDO's
• Flow rates of exhausts and forced
makeup air (test data, rated values.
or fan and duct data, as available)
• Total dimensions of the prospective
TTE (length, width, height)
* Probable locations of access doors
and windows
These data will be needed after leaving the
plant to design a TTE that meets all of the
criteria.
After completing the plant tour, meet
with facility representatives to review and
verify the information that has been gathered.
Identify any information gaps and make plans
to obtain the missing information. Discuss
alternative TTE configurations and test
locations to determine whether facility
representatives are concerned about any of the
possibilities brought up during the visit.
After the Plant Visit
The next step is to evaluate potential TTE
designs against the criteria and pick one for
further design work. In evaluating the criteria
and designing the TTE, remember that some
parameters are flexible. For example, certain
NDO's may be required by the process, bu;
additional NDO's (up to 5 percent of the totaJ
TTE area) can be added as desired to adjust
FV or improve the ventilation of the TTE
Similarly, while the airflow volumes of
existing, permanent exhausts and makeup air
ducts are set. the temporary exhaust volum-j
can be sized to achieve the desired FV.
However, the higher the exhaust volumes, the
greater the size and expense of the exhaust
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PAGE:I
system and the greater the likelihood of
affecting normal airflow patterns.
Designing the NDO's and the temporary
exhaust system is an interactive process
because both affect FV. When adjustments are
contemplated for either, the effect on FV must
be determined in order to be sure that the FV
criterion is met. Also, NDO's added to affect
FV and/or improve TTE ventilation must be
evaluated against the distance and 5 percent
criteria. Finally, remember that the airflow
volumes used for design are estimates that may
vary under actual test conditions: changes to
the NDO's and/or temporary exhaust rate may
be needed when the actual flow rates are
determined in the field.
Steps for Evaluation and Design
A general stepwise approach to
evaluating potential TTE configurations and
designing the selected TTE is presented below.
An example case study is presented in
Appendix D.
1. Determine the location and
dimensions ot" any NDO's essential
for normal operation of the process
(e.g., the NDO's needed to allow the
raw material to enter and the end
product to exit). Evaluate the NDO
distance criteria (NDO/VOC source
distance and NDO/exhaust point
distance) and the criterion that the
total NDO area must be less than or
equal to 5 percent of the total area of
the TTE (see Chapter 4 for the
criteria). Eliminate those potential
TTE configurations that cannot
meet these requirements. In some
cases, if the line-of-sight distances
are inadequate to meet the distance
criteria, temporary baffles may be
installed to increase the effective
distances. If baffles are used, make
sure the baffles do not interfere
with the normal airflow patterns.
2. Determine the volume of the
permanent exhaust(s) from the
TTE, such as the exhaust to the
control device. If the facility has a
forced makeup air system with a
vent inside the TTE, determine the
volume of air introduced into the
enclosure.
3. Estimate the temporary exhaust rate
needed to maintain the atmosphere
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PAGE 22
inside the TTE at a safe and healthful
level. One approach to estimating
this parameter involves the Grumpier
Chan included in Method 204 (see
Appendix B). Additional
information on estimating the
required temporary exhaust rate is
included in Appendix C. If
personnel must enter the TTE, the
target VOC concentration must be
less than the Occupational Safety and
Health Administration (OSHA)
Permissible Exposure Limit (PEL)
for the VOC's being emitted by the
process. If personnel are not inside
the TTE during the test period, the
target VOC concentration should be
25 percent or less of the lower
explosion limit (LEL).
It is theoretically desirable to
duplicate the ambient VOC concen-
tration that would be present if the
TTE were absent. However, this
could require a very high exhaust
rate, which could upset normal
conditions within the TTE. In
addition, an elevated exhaust rate
increases the size of the system,
making the logistics of installation
more difficult and increasing the
cost.
4. Using the data developed ir. Steps 2
and 3 above, calculate the -istimated
net totaJ exhaust rate from the TTE.
This rate is computed by summing
the various exhausts and subtracting
any forced makeup air volume.
Using this net exhaust rate and the
area of the essential NDO's from
Step 1 (i.e., the minimum NDO
area), calculate the average FV and
compare it with the 200 ft/min
criterion (see Appendix A-l).
If the FV does not meet the
criterion, the temporary exhaust
rate can be increased so the velocity
does meet the criterion. Typically,
however, the total exhaust rate
needed to maintain the TTE
atmosphere below the OSHA PEL's
is greater than the amount of air
needed to maintain a FV of greater
than 200 ft/min. This excess
airflow allows installation of
additional NDO's to improve the
ventilation of the TTE.
5. After calculating the FV in Step 4,
select a target FV that exceeds the
minimum (to allow a margin for
error) but is not excessively high
(e.g., 250 ft/min). Using the
selected target FV and the estimated
net exhaust rate determined in
Step 4, calculate the maximum
NDO area that can achieve the
target FV. Also, calculate the
maximum N'DO area that can be
used and still meet the 5 percent
criterion.
6. Select the smaller of the two
maximum NDO area values
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PAGE 23
calculated in Item 5. Use this NDO
area to evaluate possible locations
and NDO sizes that will meet all the
criteria and provide good ventilation
of the TTE. Take care to minimize
any disruption of normal VOC
capture (i.e., avoid impinging on
VOC sources or on airflow patterns
near capture points).
As stated earlier, remember that the
calculations performed here are approxima-
tions, and adjustments will be required in the
field when actual flow rates are determined
and the actual NDO and TTE areas are
established.
Oiher Design Considerations
In addition to the TTE criteria that must
be met. there are other considerations that
should be factored into the potential TTE
configuration. Some of these are:
• The TIE must isolate the emissions
from the affected facility from all
other emissions both in terms of
pickup by the TTE and at measure-
ment points within the ducts.
* The operation inside the TTE during
the test should duplicate, as much as
possible, normal operating conditions
that would be encountered without
the TTE.
« The NDO's should be at locations
that will ensure good mixing of the
air within the TTE. Try to eliminate
stagnant areas where the VOC
concentration could build up, such as
the comers of the TTE away from the
process and exhaust points. This
ensures that VOC concentrations are
uniform throughout the TTE.
* The NDO's and temporary exhaust
inuke(s) should be located so that the
predominant flow of air through the
enclosure will "sweep" the fugitive
emissions from the TTE. For
example, consistent with the TTE
criteria and other considerations, the
NDO's may be concentrated on one
end of the TTE (at various
elevations), while the temporary
exhaust intake is placed at the
opposite end of the enclosure. Where
possible, it is also preferable to sweep
fugitive emissions away from
personnel work areas.
« Evaluate the proposed location of the
NDO's relative to the locations of the
exhaust pickups for the captured and
fugitive emissions to ensure that air is
not channelled directly from the NDO
to the exhaust duct. If this happens,
the TTE could be ventilated
improperly. Keep in mind the four
equivalent diameter distance criterion
when evaluating the proposed
location.
* Remember that the VOC concentra-
tion within the TTE must reach a
constant level before testing can begin
and that the constant level must be
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PAGE 24
protective of the health of the
workers. The safety of the
employees daring the CE perfor-
mance testing is paramount-stress
this to those responsible for the
design and construction of the TTE,
* To the extent possible, NDO's should
be located away from VOC sources
outside the TTE. Although the CE
test procedures require that the
"background" VOC concentration
from such sources be measured and
accounted for, it is preferable to
avoid high-concentration sources.
* In the preliminary selection of a
target FV, consider the potential
impact of an excessively high flow
rate. The pressure differential
required to maintain a FV of
200 ft/min is about 0.004 inch of
water (in. H2O); for a FV of
500 ft/min, about 0.024 in. H20 is
required. These pressures are tor
small to appreciably affect the
performance of the permanent capture
devices, but, over a large TTE
surface area, the total pressure
becomes significant. Because the FV
is created by the difference in
pressure on either side of the TTE
wall, the greater the FV, the greater
the structural stresses that will be
applied and the greater the structural
suppon that will be required (and
greater cost).
* If a large drying oven is pan of the
process, the TTE need not enclose the
entire oven if the air flow is into the
ovens so that VOC does not escape
from the oven.
• During the actual capture efficiency
performance testing, a number of
tests will be required. Evaluate the
proposed design to ensure that these
tests can be conducted. The two
major tests are:
1. Measuring flow rates in exhaust
ducts and forced makeup air
ducts to ensure that the average
FV across the NDO's is at least
200 ft/min.
2. Measuring the CE, which is
comprised of three components:
(a) captured VOC emissions test
point(s);
(b) fugitive VOC emissions test
point(s); and
(c) background VOC test point(s).
After evaluating the potential TTE
configurations and selecting the most desirable.
determine the quantities of materials.
manpower, and equipment needed to build the
TTE. In most cases, this step will be
carriedout by a building contractor or the
appropriate facility personnel.
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PAGE 25
Construction Materials
Various construction materials that may
be used for the TTE are discussed below.
Two basic types of TTE construction materials
are discussed: plastic film and rigid materials.
With any of these construction options, site-
specific factors will influence the final
configuration and support structure of the
TTE. To the extent possible, existing walls
and other structures at the plant should be
incorporated into the TTE to minimize
construction costs.
Plastic Film for TTE's
Using plastic film for the surface of a
TTE has a number of advantages. Its light
weight minimizes the complexity and strength
required of the TTE support structure.
Because it is fairly transparent, process
operation can be monitored from outside the
TTE, and existing lighting outside the TTE
will generally be adequate to light the interior.
Plastic film is easy to work with; it can be cut
to accommodate obstructions and taped or
glued to form a seal around an obstruction.
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PAGE 26
Plastic film can be rapidly deployed when the
supporting framework has been prepared.
This property is useful for baseline testing
without the TTE in place-the framework can
be constructed, the plastic film put in place
and then raised out of the way, baseline testing
conducted, the plastic film deployed, and
testing with the TTE in place begun with a
minimum of lag time between test periods.
Plastic film is also relatively inexpensive.
Disadvantages include flimsiness, relatively
low melting point, potential static buildup, and
flammability.
Two basic options are available for
supporting a plastic film TTE, depending on
site-specific conditions. These options are:
Self-supporting framework: The
framework is custom-constructed onsite to
support the four walls and roof of the TTE or
to augment any existing structures that could
be incorporated into the TTE as walls or
supports. Self-supporting frameworks can be
constructed of such materials as wood, plastic
piping, or scaffolding.
Suspend rom
structure
Where possible, an attractive option is to
suspend plastic film waJIs from the facility
ceiling, using the ceiling as the TTE's roof.
This configuration does away with the need to
provide a self-supporting framework for the
TTE roof. Some support for the plastic
sheeting may be needed against outside
pressure on the walls, particularly for large
TTE's. Wall support may be provided by the
same types of materials mentioned above.
Another option is using wire strung from the
ceiling and anchored to the floor at the comers
and intermediate points.
An impediment to suspending the TTE
walls from the ceiling is the presence at many
facilities of roof supports and other
obstructions (e.g., steam piping, ventilation
ductwork, and electrical conduit) near roof
level. Tailoring the plastic film walls to
accommodate these obstructions with a
minimum of open area could become a lengthy
and difficult task. At some facilities, this
problem can be avoided by suspending the
plastic walls from the obstructions themselves.
In such cases, the open areas between the top
of the plastic walls and the facility ceiling must
be considered NDO's. This approach will
only be feasible where these NDO's meet the
criteria. Otherwise, a TTE roof must be
constructed, or the TTE walls must be
extended to the facility ceiling.
Rigid Materials
In some cases, TTE's may be constructed
of rigid materials. These TTE's will lack the
advantages of plastic film construction
discussed previously, but other factors may
outweigh such considerations. Two alterna-
tives for constructing a TTE with rigid
materials are:
Insulation panels. One facility at which
a TTE/CE test was conducted used insulation
panels joined with duct tape to construct the
TTE. This type of construction is desirable
where the panels can be anchored to existing
structures to form a self-supporting TTE.
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PAGE 27
Plywood: A TTE constructed of
plywood is desirable where great structural
integrity is necessary. For example, an
outdoor test might require such construction.
CONSTRUCTION
The design of the TTE is unique to each
site because the design depends on the specific
arrangement of the process within the building
and the proximity of other processes to the one
being tested. It is important to remember that
the lit and the subsequent tests should allow
for the normal operation of other facilities
within the plant to avoid the costs of lost
production, which can be substantial.
During construction of the TTE, it is
helpful if State agency personnel who will
oversee the performance testing are onsite to
answer questions that will arise and to observe
that the TTE is being constructed properly.
Although it is the responsibility of the TTE
contractor to build the structure correctly, the
State will ultimately determine whether the
TTE is acceptable for testing purposes.
Safety during construction is very
important both in terms of worker safety and
potential damage to processes operating in the
immediate vicinity of the TTE construction.
At any construction site where work is being
conducted overhead, there is a significant
potential for dropped tools and lumber that can
injure workers beneath the structure.
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PAGE 28
Timing of the TTE construction is very
important, and all concerned parties should
develop and agree to a realistic schedule
before beginning construction. Normally,
power equipment or internal combustion
cannot be used near VOC processes, so plan in
advance how and where to cut lumber and
perform other tasks requiring power
equipment. If a hoist must be used, the hoist
must be acceptable for use around VOC's
(i.e., manual or explosion-proof) or the
process must be stopped and all VOC's
removed from the area.
After construction has been completed, a
preliminary inspection of the TTE should be
conducted to determine several factors, such
as:
• Whether the sources of VOC emis-
sions within the TTE are at least
4 equivalent diameters from each
NDO and all exhaust ducts or hoods
are at least four equivalent duct or
hood diameters from each NDO.
* Whether the total area of the NDO's
is less than or equal to 5 percent of
the total area.
• Whether all access doors/windows can
be closed during the conduct of the
performance test (except for brief
openings for the entry of personnel or
necessary equipment;.
* Whether the structure is constructed in
a sound manner. Care must be taken
to ensure that workers inside the TTE
during the test periods x-e not
subjected to potentially unsafe
conditions in terms of enclosure
construction.
* Whether NDO's are adequately
placed to prevent a VOC buildup.
(VOC buildup could occur in the
corners or other quiescent areas of
the TTE.)
* Whether the structure isolates
emissions from the process to be
tested from emissions of all other
processes occurring within the same
facility.
* Whether all fugitive emissions are
directed through ducts suitable for
measuring gas stream volumetric
flow rates and VOC concentration.
Likewise, the captured emissions
must be directed through a duct
suitable for measuring gas stream
volumetric flow rate and VOC
concentration.
The preliminary inspection should be
conducted during and immediately after the
TTE is constructed. Points of inspection
include criteria such as the total NDO area and
distances from VOC sources and exhausts as
well as the noncriteria items discussed
previously. However, final judgment on the
criteria cannot be made until the TTE structure
and operating conditions have reached the final
state at which the CE testing will be con-
ducted. Only after all adjustments have been
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PAGE 29
made will a definitive criteria evaluation be
conducted.
When the preliminary inspection indicates
that the TTE is acceptable, you are ready to
begin the tests in Chapter 6.
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PAGE 30
TABLE 5-1. SAMPLE ADVANCE QUESTIONNAIRE
The following list presents the information that needs to be collected on the visit to
your facility. It is likely that some items will have to be retrieved from facility records. Any
information you can assemble prior to our visit will be greatly appreciated. A copy of the
temporary total enclosure (TTE) protocol for deteru/tning capture efficiency is attached for
your reference.
I. Process information for the process lines
(Note: lines to be specified oased on previous telephone contact.)
A. Type of process
B. Hours of operation (h/d, d/wk)
C. Is the process continuous or batch?
D. Is VOC-containing material applied at a constant or variable rate during a run?
E. Typical duration of a run
F. Is more than one coating/solvent system typically used?
If so, what are the compositions (solvents and percents) of the three most
commonly used coatings?
G. Personnel access requirements
1. Individuals that need access
2. Points in the process to which access is needed
3. Frequency and duration of access
4. Unrelated personnel traffic patterns that could affect TTE configuration or
operation (e.g., foot traffic in aisle adjacent to process)
H. Material flows
1. Within process
2. To and from process
3. Unrelated material flows that could affect TTE configuration or operation (e.g.,
forklift lane adjacent to process)
II. To aid our understanding of your facility, please supply a simplified diagram of each
process showing the process equipment, drying oven, air pollution control system, and
air handling system (including any emission capture equipment, oven recirculation
lines, makeup air intakes, combustion air intakes, etc.).
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PAGE 31
TABLE 5-1. (continued)
in. To aid in our detailed planning, please supply existing blueprints or plans of each
process area with as much detail as possible, such as:
A. Floor plan (to scale) showing process equipment and permanent structures (walls,
columns, windows, room vents, hoists, etc.)
B. Ceiling height and type of construction
C. Existing ventilation system
1. Capture system with pickup locations, dimensions, and volumetric flow rates
2. Wall/ceiling exhausts
3. Makeup air system
D. Utilities (e.g., steam piping, air ducts, electrical conduit, etc.)
IV. Applicable regulations
A. Air pollution
1. What are the "affected facilities" (i.e., equipment or processes) to which
regulations apply?
2. What are the applicable emission limitations?
3. Have emission tests been conducted? At what locations? Please provide copies
of test reports.
B. Fire Code or insurance carrier fire protection requirements. Any monitors or
automatic equipment?
C. Worker health and safety requirements
1. OSHA regulations limiting the solvent vapor concentration to which workers
are exposed. Any solvent vapor concentration monitors?
2. Noise?
3. Others?
V. To estimate the minimum exhaust rate that will p*vntain the atmosphere in the TTE at
a safe and healthful level, we need to know the identities and proportions of the solvent
vapors released into the TTE (the "fugitive" emissions) and the approximate maximum
mass emission rate. In the absence of direct measurement data, the identities and
proportions of fugitive emissions can be estimated from the coating solvent blend. To
estimate the maximum mass emission rate of fugitives, one of the following
information items is needed for the process conditions that generate the greatest mass
emission rate of fugitives:
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PAGE 32
TABLE 5-1. (continued)
A. The maximum fugitive VOC emission rate from past tests;
B. The approximate capture efficiency of existing capture system (from past tests);
C. The VOC mass flow rate to the control usvice (from past tests);
D. The volumetric flow rate and VOC concentration in all ducts leading to the control
device (from past tests); or
E. If no representative test data are available, the VOC application rate and an
estimate of the percentage emitted as fugitives. For instance, where a solvent
recovery device is used, the fugitive emission rate might be estimated by
subtracting the amount of solvent recovered from the amount used over some time
period.
VI. Information on the drying oven is needed to determine whether the oven can be
considered pan of the enclosure (or must be enclosed by the TTE), whether heat
buildup inside the TTE could be a design constraint, and whether there are potential
testing complications
A. Is the oven operated under negative pressure (i.e., air flows into the oven at all
openings)?
B. Are there any indications that solvent vapors escape from the oven during
operation? If so, how is this determined?
C. Volumetric flow rate and temperature of oven exhaust
D. Volumetric flow rate and temperature of any forced makeup air to the oven
E. Locations and dimensions of any openings into the oven (e.g., entrance and exit
slots)
F. Are any data available on the rate at which heat escapes from the oven into the
room (e.g., measured value, estimated percent of heat input, etc.)?
G. Oven operating temperature
H. Dimensions of oven
I. Are there any other significant sources of heat in the process area?
J. How many process lines does the oven serve?
K. Is the oven direct fired? If so, what is the source of combustion air? Has the
amount of solvent combusted by the burners ever been determined or estimated? If
so, how?
L. Oven air recirculation? Are recirculation ducts internal or external to the oven?
Flow diagrams available?
VH. Air pollution control system
A. Type of control device
B. Type of capture device(s) (e.g., canopy hood, floor sweeps, localized pickup
hoods, etc.)
C. Gas streams controlled (e.g., oven exhaust, hoods, etc.)
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PAGE 33
TABLE 5-2. SAMPLE CAPTURE EFFICIENCY PRETEST SITE
VISIT CHECKLIST
I. Equipment
A. Typical safety equipment-bard hat, safety glasses, steel-toed boots, ear plugs
B. Tape measure
C. Anemometer
D. VOC concentration meter
E. Sketching materials-graph paper, pen/pencil, eraser, small ruler
F. Calculator
G. Watch
H. Notebook
I. Identification
J. Copies of previous correspondence
n. Preliminary meeting
A. Discuss TTE/CE protocol and purpose of site visit
B. Discuss plant questionnaire (sent with site visit letter)
1. Hand out copies of questionnaire
2. Go through points briefly
3. Scan any information that the plant has assembled for completeness, units
(particularly acfm/scfm), etc. If possible, make preliminary determination of
whether drying oven must be enclosed.
4. Discuss availability of any missing information, particularly on solvents used,
health/safety requirements, mass emission rate of fugitives, and drying oven
III. Plant tour
A. Dau for TTE construction
1. Identify the affected facility across which CE is to be measured
2. Identify the emission points within the affected facility
3. Identify any nonaffected emission points in close proximity
4. Draw schematic of process (or verify and add to schematic supplied by plant)
showing process equipment and all gas streams
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PAGE 34
TABLE 5-2. (continued)
5. Sketch plant layout (or verify and add to plant plan supplied by plant),
including measurements; locate items below in 3 dimensions when applicable;
if unsure whether drying oven will be within or outside TTE, take
measurements for both possibilities
a. Locations and dimensions of all structural components (walls, columns,
etc.)
b. Location and dimensions of each VOC source, affected and nonaffected
c. Location, dimensions, and destination of each exhaust duct or hood
d. Locations and dimensions of plant makeup air system (e.g., windows or
forced supply ducts)
e. Note location, dimensions, and material of construction of any existing
structure that can be used as a component of the TTE or to support the
TTE (walls, columns, ceiling, ceiling supports, steam or water piping, air
ducts, hoist frame, etc.); consider and note how TTE materials can be
fastened to the existing structures
f. Note location and dimensions of any existing structures that could obstruct
construction of the TTE (same as above); consider and note how the TTE
can accommodate these structures
g. Note location of utilities that must be inside the TTE (e.g., lights)
h. Note location of any health or safety systems that must be within the TTE
(e.g., automatic fire extinguishing system or noise abatement
6. Identify personnel traffic patterns around affected facility and add to sketch as
pertinent
a. To which points in process must operator have access during process
operation? Hov/ often? For what duration?
b. How much clearance is needed around equipment?
c. Where else in plant must operator go, i.e., will the operator have to pass
in and out of the TTE during testing? How often?
d. Other personnel (e.g., supervisor) with intermittent access needs? How
often? For wh.it duration?
e. Do unrelated personnel pass in vicinity? Are alternative routes available?
7. Identify material flow patterns and add to sketch as pertinent
a. Flow within process
b. Flow to and from process (e.g., delivery and mounting of new substrate at
unwind station) with frequency and duration
c. Unrelated material flows in vicinity (e.g., forklift lane adjacent to
process), availability of alternative routes
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PAGE 35
TABLE 5-2. (continued)
8. Consider alternative TTE configurations (smallest, largest, and any suggested
by permanent structures that could be incorporated) and add to sketch
a. Take measurements in 3 dimensions
b. Identify and note any obstructions or other constraints suggested by above
data
c. Consider personnel access and material flows; note the locations and
dimensions of any prescribed NDO's
d. Consider construction issues such as how the TTE will be constructed in
close areas and how personnel can be elevated to the height necessary to
construct the TTE frame or hang plastic walls
B. Data for testing
1. Is previous test data available?
2. Can emissions from the affected facility be isolated from nonaffected
emissions?
3. Identify gas streams and points that must be tested
4. Are ducts suitable for testing, or will modifications be necessary?
5. Are data sufficient to approximate the identities, proportions, and maximum
mass emission rate of fugitives?
6. Are there any potentially complicating factors (e.g., recirculating or direct-fired
ovens, significant differences between the components in the captured and
fugitive gas streams, extremely dilute gas streams, interfering compounds)?
IV. Post-tour meeting
A. Discuss information gathered
B. Discuss additional information needs
C. Discuss alternative TTE configurations and test locations to see if plant
representatives have concerns
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PAGE 36
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PAGE 3'
CHAPTER 6
WHAT TESTS ARE REQUIRED?
In order to conduct the gas/gas capture
efficiency (CE) performance test protocol two
basic tests must be performed:
1. Average face velocity (FV) tests;
and
2. CE determination tests, which
include the following measure-
ments:
a. Fugitive volatile organic
compound (VOC) emissions;
b. Captured VOC emissions: and
c. Background VOC concen-
tration.
The average FV test must be conducted before
beginning the CE performance test. The three
components of the CE performance test are
conducted simultaneously. The CE
determination testing procedures presented in
Appendix B require three sampling runs with a
sampling time of from 3 to 8 hours for each
run.
AVERAGE FACE VELOCITY TEST
Measure the volumetric flow rate,
corrected to standard conditions, of each gas
stream, including temporary exhaust streams,
exiting the enclosure through an exhaust duct
or hood using the procedures provided in
Appendix B, Method 204, Section 5. Quality
assurance procedures are given in Section 6 of
the procedure.
The captured exhaust from a process is
often the exhaust from the drying oven.
Determining the temporary total enclosure
(TTE) exhaust volume may be complicated if a
large drying oven is not fully enclosed by the
TTE. Typically, in such cases, the TTE is
built onto the front of the dryer so that all
emissions in the flashoff area are contained.
Thus, the entrance to the dryer is within the
TTE, and the makeup air drawn into the dryer
through the entrance is, in effect, an exhaust
from the TTE. In such cases, estimate the
quantity or percentage of the captured exhaust
from the dryer to the control device that is
drawn out of the TTE. An approximation can
be made by apportioning the total makeup air
that enters the dryer through all openings
(including those within the TTE) by the area
of the openings.
If any of the facility's forced makeup air
outlets are within the TTE, measure the
volumetric flow rate, corrected to standard
conditions, of each of the makeup air ducts.
Using the exhaust and makeup volumes and
the area of the natural draft openings (NDO's).
calculate the average FV across the NDO's as
shown in Appendix A-1. The average FV
must be at least 200 feet per minute (ft/min).
This test is illustrated in Figure 6-1.
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PAGE 38
Permanent Faolity
Forced Makeup Air Vent
Q-jSCtm
Plastic
Streamers
NOO
with Area A
Face Velocity Test:
Captured Emission Stream
Qosctm
I To Control
Device
Temporary Exhaust for
Fugitive Emissions
Qf scfm
FV must be 2 200 ft/min and demonstrably inward
Figure 6-1. The average face velocity test.
In addition to calculating the FV.
observe the actual direction of flow at the
NDO's to verify that the direction of airflow
through all of the NDO's is inward. This can
be done using various methods, such as
streamers, smoke tubes, or tracer gases.
Strips of plastic wrapping film hung in the
NDO's have been found to be an effective
indicator. Monitor the-direction of the airflow
at intervals of 10 minutes for at least 1 hour.
After calculating the average FV and
determining that the velocity criterion of
greater than 200 ft/min has been met, inspect
the TTE rigorously to verify that all of the
other criteria are met. These criteria include
the distances from the NDO's to the exhausts
and to the VOC sources, the NDO area ratio
to the total TTE area. NDO directional
airflow, and other criteria discussed in
Chapters 4 and 5. If the TTE meets all of the
criteria, the performance tests can be
conducted. During the performance tests.
verify that all access windows and doors are
closed except for momentary use. If any of
the TTE criteria are not met, adjust the TTE
to correct the problem. If all the criteria are
met during the FV testing, this period can be
included in the first CE performance test run.
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PAGE 39
PERFORMANCE TESTS FOR CAPTURE
EFFICIENCY
The performance tests for CE with the
TTE require measurement of the VOC
emissions in the fugitive emissions duct(s) and
in the captured emissions duct(s). The EPA
procedures for these tests are presented in
Appendix B, Methods 204B, 204C, and 2MD.
Concurrent with the sampling and analysis
procedures for fugitives and captured
emissions, the background VOC concentration
in the makeup air entering through the NDO's
is determined. The background concentration
is subtracted from the fugitive emissions and
captured emissions in order to obtain a true
evaluation of the CE for the VOC emissions
due solely to the enclosed process. The
equations required to calculate the VOC
concentrations are provided in Appendix A.
Figure 6-2 illustrates the CE performance test.
The CE test consists of at least three
sampling runs. Each sampling run is required
to be at least 3 hours long and to cover at least
one complete production cycle (i.e., product
run), except that the sampling time need not
To Control
Device
Captured Emission Stream
with Concentration CQ
and Ftowrate QQ
BacxgrourW VOC
wnn Concentration
Background VOC
witn Concentration
CB
Temporary Exhaust lor
Fugitive Emissions
with Concentration C.
and Fiowraie QF
Performance Test:
-------
PAGE 40
exceed 8 hours even if a product run has not
been completed. A sampling run need not be
limited to a single process run. These lengthy
sampling runs are specified to ensure that the
full range of normal operating conditions are
included in the test results, including the types
of process starts and stops that are pan of
routine operations. For example, if the
process is frequently slowed or stopped for
routine equipment adjustments, testing should
continue during such periods. On the other
hand, if changeover from one product to
another takes several hours, this period may
not be considered a normal operating condi-
tion, and testing should be suspended during
the changeover. Agreement should be should
be reached ahead of time on what constitutes
"normal operations" to be included in the test
and what constitutes a malfunction,
breakdown, or nonoperating period during
which testing should be suspended.
During the test, three measurements are
being made simultaneously:
1 Fugitive VOC emissions-measure
VOC concentration and volumetric
flow rate
2. Captured VOC emissions-measure
VOC concentration and volumetric
flow rate
3. Background VOC-measure only the
VOC concentration at up to six
sampling points
For these measurements, the VOC concentra-
tion is typically measured with a flame
ionization analyzer (FIA) according to EPA
Method 25A, and the volumetric flow rate is
measured using EPA Methods 2, 2A, 2B, 2C,
or 2D. Other reference methods that may be
used are referenced at the end of this chapter.
The captured and the fugitive VOC
emissions are measured in all of the ducts
containing these emissions. If multiple
sampling points are used for any of the three
measurements (i.e., captured VOC's, fugitive
VOC's, background), sampling is systema-
tically switched from one sampling point to
another so that an equal quantity of gas is
sampled from each point. Procedures for
changing from one sampling point to another
are provided in Methods 204B, 204C, and
204D in Appendix B. Additionally, all pretest
system checks and quality assurance (QA)
requirements are provided in Methods 204B.
204C, and 204D.
Fugitive VOC Emissions
The quantity of fugitive VOC emissions (?)
from the TTE is the product of the VOC
content, the flow rate, and the sampling time.
summed over all of the fugitive emissions
ducts. To run a test, set up a measurement
system similar to Figure 204D-1 in Method
204D (see Appendix B) and measure the
fug'tive emission flow rate and VOC
concentration for the duration of the test.
Check several QA items before running the
test (see Method 204D). The equations,
including sample calculations, required to
calculate fugitive VOC levels are provided in
Appendix A.
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PAGE 41
Captured VOC Emissions
This procedure is presented in Appendix B
for the normal technique (Method 204B) and
the dilution technique (Method 204C). The
quantity of captured VOC emissions (G) is the
sum over all the captured emission ducts of the
product of the VOC content, the flow rate, and
the sampling time for each duct. The dilution
technique is used to allow the use of & single
FIA to measure both captured VOC's and
fugitive VOC's. The equations used to
calculate the captured VOC emissions are
presented in Appendix A.
Background Tests
The average background VOC
concentration in the ambient air flowing into
the NDO's must be determined by sampling
and analyzing the air in the immediate vicinity
of the NDO's concurrent with the testing of
fugitive and captured emissions. The
procedure for measuring the background
concentration is presented in Appendix B
(Section 4.3 of Methods 204B. 204C, and
204D). Setup for the background tesi.s
includes the following steps:
1. Locate all NDO's of the TTE.
2. Place a sampling point at the center
of each NDO.
3. If more than s"ix NDO's are present in
the TTE, choose six sampling points
evenly spaced among the NDO's.
4. Assemble a sample train as shown in
Methods 204B, 204C. and 204D.
This sample train must be separate from
the one to measure captured or fugitive
emissions. The sampling and analysis pretest
procedures are the same as those used for
measuring the VOC content of the captured
and fugitive emissions. The equations,
including sample calculations, required to
calculate the background VOC concentration
are provided in Appendix A.
Applicable EPA Methods
The following list provides references for
test methods that may be used during capture
efficiency performance tests. Not all of these
tests are referenced in this document. This
comprehensive list is provided in the event that
certain circumstances at a specific site may
require one of the nonreferenced test methods.
Method 1 Sample and Velocity Traverses
for Stationary Sources, 40 CFR 60,
Appendix A.
Method 1A Sample and Velocity Traverses
for Stationary Sources with Small Stacks or
Ducts.
Method 2 Determination of Stack Gas
Velocity and Volumetric Flow Rate (Type
S Pitot Tube) 40 CFR 60, Appendix A.
Method 2 A Direct Measurement of Gas
Volume Through Pipes and Small Ducts,
40 CFR 60, Appendix A.
Method 2B Determination of Exhaust Gas
Volume Flow Rate from Gasoline Vapor
Incinerators, 40 CFR 60, Appendix A.
-------
PAGE 42
Method 2C Determination of Stack Gas
Velocity and Volumetric Flow Rate from
Small Sucks or Ducts (Standard Pilot
Tube).
Method 2p Measurement of Gas Volume
Flow Rates in Small Pipes and Ducts.
Method 3 Gas Analysis for the
Determination of Dry Molecular Weight,
40 CFR 60, Appendix A.
Method 4 Determination of Moisture
Content in Stack Gases, 40 CFR 60,
Appendix A.
Method 18 Determination of Gaseous
Organic Compounds by Gas
Chromatography, 40 CFR 60,
Appendix A.
Method 25 Determination of Total
Gaseous Nonmethane Organic Emissions as
Carbon. 40 CFR 60, Appendix A
Method 2j.A Determination of Total
Gaseous Organic Concentrations Using a
Flame lonization Analyzer, 40 CFR 60,
Appendix A
Method 25B Determination of Total
Gaseous Organic Concentration Using a
Nondispersive Infrared Analyzer, 40 CFR
60, Appendix A.
-------
APPENDIX A
EXAMPLE CALCULATIONS
A-l Average Face Velocity
A-2 VOC Concentration of Fugitive Emissions at Each Sampling Site
A-3 Total VOC Fugitive Emissions
A-4 VOC Concentration of Captured Emissions at Each Sampling Site
A-5 Total VOC Captured Emissions
A-6 Background VOC Concentrations at Each Sampling Site
A-7 Average Background Concentration
A-8 Capture Efficiency
-------
_ PAGE A-l
A-l. AVERAGE FACE VELOCITY
Calculate average face velocity (FV) using the following equation:
QO-QI
FV = -^ - —
AN
where:
Qo = the sum of the volumetric flow from all gas streams exiting the enclosure through an
exhaust duct or hood, corrected to standard conditions.
Q. = the sum of the volumetric flow from all gas streams into the enclosure through a forced
makeup air duct, corrected to standard conditions; zero if there is no forced makeup air
into the enclosure.
A., = total area of all natural draft openings (NDO's) in the enclosure.
Example 1. Simple case. There are the minimum two exhausts from the enclosure, a single
captured gas stream to the control device (Q~ = 3,000 scfm) and a single temporary exhaust for
fugitive emissions (Qp = 3,000 scfm). There are no forced makeup air inlets. There are two
NDO's, the entrance and exit slots (each 6 ft x 2 ft) for a continuous web.
Q0 = 0G + QF
= 3.000 scfm + 3,000 scfm
= 6.000 scfm
= 0 scfm
-------
PAGE A-2
= Al + A2 -
= (6 ft x 2 ft) + (6 ft x 2 ft)
= 24ft2
FV
AN
6,000 scfm - 0 scfm
24 ft2
250 ft/min
Example 2. Complex case. The enclosure is built around the application and flashoff areas of a
coating process; oniy the entrance to the large drying oven is inside the enclosure. The oven
exhaust (Q0ven = 6,000 scfrn) is vented to the control device. All the oven makeup air is
drawn in through its entrance slot (5 ft x 2 ft) and its exit slot (5 ft x 1 ft). Thus, the oven
entrance slot functions as an exhaust from the enclosure (QOVen entrance^ A permanent hood
over the applicator exhausts to the atmosphere (Qnd ~ ^ scfm). A temporary exhaust for
the fugitive emissions (Qp = 7,000 scfm) is necessary to maintain a healthful atmosphere. An
outlet of the facility's forced makeup air system (Qj = 6,000 scfm) is located inside the
enclosure. The enclosure has an entrance slot for the web that is 4 ft x 2 ft. Additional NDO's
have been provided to improve the ventilation of the enclosure (six at 17 in. x 17 in. and six at
I ft x 1 ft).
In the absence of better data, Qoven entrance can be approximated by apportioning the oven makeup
air volume fwhich is equal to its exhaust rate, QOVen* amonS ^e openings in the oven according to
each opening's area:
Qoven entrance = Qoven x
Aoven entrance
Aoven entrance "*" Aoven exit
f. AAA * 5 ft X 2 ft
= 6.000 scrm
(5 n x 2 ft) - (5 n x i ft]
= 4.000 SCfTT:
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PAGE A-3
Qoven entrance + Qhood + Qp
= 4,000 scfm -f 800 scfm -r 7,000 scfm
= 11,800 scfm
0] = 6,000 scfm
AN = ^enclosure slot "*" Aadded NDO's
= (4 ft x 2 ft) + 6 (P '"' X 17 '"^ + 6 (1 ft x 1 ft)
144 in.:/ft2
= 8 ft2 + 12 ft2 + 6 ft2
= 26ft2
FV =
11 .800 scfm - 6,000 scfm
= 223 ft/min
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PAGE
A-2. VOC CONCENTRATION OF FUGITIVE EMISSIONS AT EACH
SAMPLING SITE
where:
CFj = (Cj - CDO)
CDH ' CDO
C; =
corrected average VOC concentration of fugitive emissions at point j, ppm propane.
uncorrected average VOC concentration measured at point j, ppm propane.
Average system drift check concentration for zero concentration gas. ppm propane.
acruaJ concentration of the drift check calibration gas, ppm propane.
av^rage measured concentration for the drift check calibration gas, ppm propane.
Example. (See Method 204D in Appendix B for the details of the measurment and quality
assurance procedures.) The concentration of fugitive emissions from a process is expected to be
in the range of 200 ppm as propane. A flame ionization analyzer with a span value of 300 ppm
as propane is used to measure the fugitive emissions. In addition to zero gas, calibration gases
with propane concentrations of 75 ppm, 150 pprn, and 225 ppm are used. System drift checks
are made with the 225 ppm calibration gas (C^) and the zero gas. The test contractor chooses
to perform drift checks each hour during the sampling runs. For Run No. I, the average value
measured for the zero gas during drift checks (Crx)) is 5 ppm propane. The average for the
drift check calibration gas measurements (CpH) 's 219 ppm propane. The average measured
fugitive emissions concentration (Cj) is 187 ppm as propane.
.87PP.-5PP.,
= 191 ppm as propane
-------
where:
PAGE A-5
A-3. TOTAL VOC FUGITIVE EMISSIONS
F- t
(Cpj - CB) Qpj flp KI
F = total VOC content of fugitive emissions, kg.
Cpj = corrected average VOC concentration of fugitive emissions at point j, ppm propane.
CQ = average background concentration, ppm propane.
Qpi = average effluent volumetric flow rate corrected to standard conditions at fugitive
emissions point j, m3/min.
0p = total duration of fugitive emissions sampling run, min
Kj = 1.830 x 10"6 kg/(m3 • ppm).
n = number of measurement points.
Example. A process is tested in which a permanent hood is exhausted to the atmosphere and a
temporary exhaust is installed to supplement the ventilation of the enclosure. Both exhausts are
considered fugitive emissions for purposes of the capture efficiency determination, and both are
measured. The hood is designated fugitive exhaust No. 1; the temporary exhaust is designated
fugitive exhaust No. 2. For Run No. 1, the hood exhaust is determined to have a corrected
average VOC concentration (Cpj) of 423 ppm as propane and an average volumetric flow rate
(Qpl) of 23 standard m3/min. For the same run, the temporary exhaust has a corrected average
VOC concentration (Cp2) of 157 ppm as propane and an average volumetric flow rate (Qp2) °f
118 standard nr/min. The average background concentration for the run (Cg) is 24 ppm as
propane; the duration of the run (0p) is 480 min.
* . ^} (CFJ - CB) Qpj 0F K!
= (423'ppm - 24 ppm) x 23 m3/min x 480 min x 1.830 x 10"6 kg/(m3 • ppm) +
(157 ppm - 24 ppm) x 188 m3/min x 480 min x 1.830 x 10T6 kg/(m3 • ppm)
= 30kg
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PAGE A-6
A-4. VOC CONCENTRATION OF CAPTURED EMISSIONS AT EACH
SAMPLING SITE
- CDO)
CDH ' CDO
where:
= corrected average VOC concentration of captured emissions at point j, ppm
propane.
C; = uncorrected average VOC concentration measured at point j; ppm propane.
DO = average system drift check concentration for zero concentration gas. ppm
propane.
CH = actual concentration of the drift check calibration gas, ppm propane.
~ Average measured concentration for the drift check calibration gas, ppm propane.
Example. (See Method 2046 in Appendix B for the details of the measurment and quality
assurance procedures.) The concentration of captured emissions from a process is expected to
be in the range of 1,200 ppm as propane. A flame ionization analyzer with a span value of
2,000 ppm as propane is used to measure the fugitive emissions. In addition to zero gas,
calibration gases with propane concentrations of 500 ppm, 1,000 ppm, and 1,500 ppm are used.
System drift checks are made with the 1,000 ppm calibration gas (C^) and the zero gas. The
test contractor chooses to perform drift checks each hour during the sampling runs. For Run
No. 1, the average value measured for the zero gas during drift checks (CrjQ) is 23 ppm
propane. The average for the drift check calibration gas measurements (C^n)is 1.039 Ppm
propane. The average measured captured emissions concentration (Cp is 1,278 ppm as propane.
CH
= (1,278 ppm - 23 ppm) -.-f,
KU39 ppm - ij ppr
1,235 ppm as propne
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PAGE A-7
A-5. TOTAL VOC CAPTURED EMISSIONS
n
G = £ (CGj - CB) QGj 6C Kj
where:
G = total VOC content of captured emissions, kg.
CG; = corrected average VOC concentration of captured emissions at point], ppm propane.
CQ = average background concentration, ppm propane.
= average effluent volumetric flow rate corrected to standard conditions at captured
emissions point j, m3/min.
>£ = total duration of captured emissions sampling run, min.
Cj = 1.830x lO^kg/Cm3 • ppm).
n = number of measurement points
Example. A process to be tested has a nood and a drying oven that are vented to a common
control device, which also controls emissions from several other procesess at the facility.
Unfortunately, the two captured gas streams from the process of interest are not combined into a
common duct before being mingled with gas streams from other procesess. As a result, each of
the two process exhausts must be measured individually. The hood is designated as captured
emissions point No. 1; the oven exhaust is designated as point No. 2. For Run No. 1, the hood
exhaust is determined to have a corrected average VOC concentration (CQ\) of 423 ppm as
propane and an average volumetric flow rate (QQJ) of 23 standard m^/min. For the same run,
the oven exhaust has a corrected average VOC concentration (£52) of 1/761 PPm *$ propane
and an average volumetric flow rate (QG2) °f ^7 standard m^/min. The average background
concentration for the run (Cg) is 24 ppm as propane; the duration of the run (6^) 's 4^0 min.
J " 1.
= (423 ppm - 24 ppm) x 23 m^/min x 480 min x 1.830 x KT6 kj/(m3 •ppm) +
(1,761 ppm - 24 ppm) x 137 m3/min x 480 min x 1.830 x 10"" kg/(m* • ppm)
= 217kg
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PAGE A-8
A-6. BACKGROUND VOC CONCENTRATIONS AT EACH
SAMPLING SITE
j - cDO)
CDH - CDO
where:
Cgj = corrected average VOC concentration of background emissions at point i, ppm
propane.
Cj = uncorrected average background VOC concentration measured at point i, ppm
propane.
average system drift check concentration for zero concentration gas, ppm propane.
actuaJ concentration of the drift check calibration gas, ppm propane.
average measured concentration for the drift check calibration gas, ppm propane.
Example. The background VOC concentration in the building housing the process to be tested
is expected to be in the range of 60 ppm as propane. A flame ionization analyzer with a span
value of 100 ppm propane is used for the background measurements. Calibration gases with
propane concentrations of 25 ppm, 53 ppm, and 75 ppm are used. System drift checks are
performed each hour during the sampling runs using zero concentration gas and 50 ppm
calibration gas (C^). At one background measurement point, the average measured VOC
concentration (C;) for one sampling run is 67 ppm as propane. For the same run, the average
drift check concentration tor the calibration gas (CrjH^ 's 53 ppm, and the average for the zero
gas (CDQ) is 2 pprn.
:Bi =
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PAGE A-9
A-7. AVERAGE BACKGROUND CONCENTRATION
i = 1
where:
Cg = average background concentration, ppm propane.
Cgj = corrected average VOC concentration of background emissions at point i. ppm
propane.
Aj = area of NDO i, ft2.
A\; = total area of all NDO's in the enclosure, fr.
n = number of measurement points.
NOTE: If the concentration at each point is within 20 percent of the average concentration of all
points, the arithmetic average concentration may be used:
CBi
i = 1
CB
Example 1. Few NDQ's. A test enclosure is constructed with three NDO's (n=3): (1) a
6 ft x 3 ft web entrance slot (Aj = 18 ft2) in one end, (2) a 6 ft x 1 ft web exit slot
(Aj = 6 fr") at the opposite end, and (3) a 3 ft x 5 ft opening for an overhead crane
(A^ = 15 fr) near the top of one side. Thus, the total NDO area (Ajv>) is 39 ft2. The end of
the enclosure with the web entrance slot is located near the mix area for the plant, where the
ambient VOC concentration is much higher than in other areas. For the test, sampling lines are
placed at the center .of each of the NDO's. The corrected average background concentrations as
propane at the three measurement points are determined to be 83 pro (Cjji), 26 ppm (Cjg).
23 ppm (€53), respectively.
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PAGE A-10
Step I. Determine whether the average concentration can be used.
CBi
i = 1 _ 83 ppm 4- 26 ppm + 23 ppm
_ = _.j
= 44 ppm as propane
83 ppm # 44 ppm ± 20 percent
.'. The average cannot be used.
Step 2. Calculate the weighted average concentration.
L CBi Aj
r ' = '
CB =
<83 ppm x 18 ft2) + (26 ppm x 6 ft2) + (23 ppm x 15 ft2)
39 n2
= 51 ppm as propane
Example 2. Many N'DO's. A large test enclosure is built with many small NDO's widely
spaced over the surface to ensure that no stagnant air pockets develop inside. For the test, six
sampling lines are spaced evenly among the NDO's around the enclosure (n = 6). Under these
circumstances, when the sampling points cannot be correlated directly to particular NDO's, an
average of the individual concentrations is computed regardless of the variation among the
individual values. For the six sampling points, the corrected average background concentrations
as a propane (Cgj's) are determined to be 44 ppm, S3 ppm, 39 ppm, 47 ppm, 57 ppm, and
54 ppm, respectively.
44 ppm •»• 53 ppm + 39 ppm - 47 ppm •*• 57 ppm + 54 ppm
=
= 49 ppm as propar.i
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PAGEA-11
A-8. CAPTURE EFFICIENCY
G
CE =
G -t- F
where:
CE = VOC capture efficiency.
G = total VOC content of captured emissions, kg.
F = total VOC content of fugitive emissions, kg.
Example. Using the procedures presented previously, it is determined that the total quantity of
VOC emissions from the tested process that are captured during a test run (G) is 290 kg. "Die
total quantity of fugitive VOC emissions (F) is determined to be 36 kg.
290
29U i- 36
0.89 or 89 percent
-------
APPENDIX B
TEST PROCEDURES
Method 204 Criteria for and Verification of a Permanent or Temporary Total Enclosure
Method 204B Volatile Organic Compound Emissions in Captured Stream
Method 204C Volatile Organic Compound Emissions in Captured Stream (Dilution
Technique)
Method 204D Volatile Organic Compound Emissions in Fugitive Stream from Temporary
Total Enclosure
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PAGE B-l
Method 204 - Criteria for and Verification of a Permanent or
Temporary Total Enclosure
1. INTRODUCTION
1.1 Applicability. This procedure is used to determine whether a permanent or temporary
enclosure meets the criteria of a total enclosure.
1.2 Principle. An enclosure is evaluated against a set of criteria. If the criteria are met and
if all the exhaust gases from the enclosure are ducted to a control device, then the volatile organic
compounds (VOC) capture efficiency (CE) is assumed to be 100 percent and CE need not be
measured. However, if pan of the exhaust gas stream is not ducted to a control device. CE must be
determined.
2. DEFINITIONS
2.1 Natural Draft Opening (NDO) - Any permanent opening in the enclosure that remains
open during operation of the facility and is not connected to a duct in which a fan is installed.
2.2 Permanent Total Enclosure (PTE) - A permanently installed enclosure that completely
surrounds a source of emissions such that all VOC emissions are captured and contained for discharge
to a control device.
2.3 Temporary Total Enclosure (TIE) -- A temporarily installed enclosure that completely
surrounds a source of emissions such that all VOC emissions are captured and contained for discharge
through ducts that allow for the accurate measurement of VOC emissions.
3. CRITERIA FOR TENfPORARY TOTAL ENCLOSURE
3.1 Any NDO shall be at least 4 equivalent opening diameters from each VOC emitting
point unless otherwise specified by the Administrator.
3.2 Any exhaust point from the enclosure shall be at least 4 equivalent duct or hood
diameters from each NDO.
3.3 The total area of all NDO's shall not exceed 5 percent of the surface area of the
enclosure's four walls, floor, and ceiling.
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PAGE B-2 __
3.4 The average facial velocity (FV) of air through all NDO's shall be at least 3,600 m/hr
(200 fpm). The direction of air flow through all NDO's shall be into the enclosure.
3.5 All access doors and windows whose areas are not included in Section 3.3 and are not
included in the calculation in Section 3.4 shall be closed during routine operation of the process.
4. CRITERIA FOR A PERMANENT TOTAL ENCLOSURE
4.1 Same as Sections 3.1 and 3.3-3.5.
4.2 All VOC emissions must be captured and contained for discharge through a control
device.
5. PROCEDURE
5.1 Determine the equivalent diameters of the NDO's and determine the distances from each
VOC emitting point to all NDO's. Determine the equivalent diameter of each exhaust duct or hood
and its distance to all NDO's. Calculate the distances in terms of equivalent diameters. The number
of equivalent diameters shall be at least 4.
5.2 Measure the total area (\) of tiie enclosure and the total area (AN) of all NDO's of the
enclosure. Calculate the NDO to enclosure area ratio (NEAR) as follows:
NEAR = -J! Eq. 204-o
AT
The NEAR must be SO.Q5.
5.3 Measure the volumetric flow rate, corrected to standard conditions, of each gas stream
exiting the enclosure through an exhaust duct or hood using EPA Method 2. In some cases (e.g.,
when the building is the enclosure), it may be necessary to measure the volumetric flow rate,
corrected to standard conditions, of each gas stream entering the enclosure through a forced makeup
air duct using Method 2. Calculate FV using the following equation:
™ • T
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PAGE B-3
where:
QQ « the sum of the volumetric flow from all gas streams exiting the enclosure through
an exhaust duct or hood.
Qj = the sum of the volumetric flow from all gas streams into the enclosure through a
forced makeup air duct; zero, if there is no forced makeup air into the enclosure.
AN = total area of all NDO's in enclosure.
The FV shall be at least 3,600 m/hr (200 rpm).
5,4 Verify that the direction of air flow through all NDO's is inward. Streamers, smoke tubes.
tracer gases may be used. Strips of plastic wrapping film have been found to be effective. Monitor
the direction of air flow at intervals of at least 10 minutes for at least 1 hour.
6. QUALITY ASSURANCE
6.1 The success of this protocol lies in designing the TTE to simulate the conditions that exist
without the TTE, i.e., the effect of the TTE on the normal flow patterns around the affected facility
or the amount of fugitive VOC emissions should be minimal. The TTE must enclose the application
stations, coating reservoirs, and all areas from the application station to the oven. The oven does not
have to be enclosed if it is under negative pressure. The NDO's of the temporary enclosure and a
fugitive exhaust fan must be properly sized and placed.
6.2. Estimate the ventilation rate of the TTE that best simulates the conditions that exist
without the TTE, i.e., the effect of the TTE on the normal flow patterns around the affected facility
or the amount of fugitive VOC emissions should be minimal. Figure 204-1 may be used as an aid.
Measure the concentration (CG) and flow rate (QG) of the captured gas stream, specify a safe
concentration (Cp) for the fugitive gas stream, estimate the CE, and then use the plot in Figure 204-1
to determine the volumetric flow rate of the fugitive gas stream (Qp). A fugitive VOC emission
exhaust fan that has a variable flow control is desirable.
6.3 After the TTE is constructed, monitor the VOC concentration inside the TTE. This
concentration shall not continue to increase and must not exceed the safe level according to
Occupational Safety and Health Administration requirements for permissible exposure limits. An
increase in VOC concentration indicates poor TTE design or poor capture efficiency.
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PAGE B-4
7.3
t -
3.:
! I
i I-
E -
«• c
- c
I
ii §
I—1| U
e _,
3.32',-
A I
\;
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=0
555 -ao:ure
\,
^ 1 ' i
^•i^SK Cioture
i '< :
1 i
o.::
0.5 1.3 1.5 2.3 2.5
Volumetric f'ewrat« of ?-jqlt:ve -niiilons
3.:
Or
Voluattric f'owritt of Q*s Scrt*m Ceilvtrea 53 :n« Control "evice £3
Figure 204-1. The crumpler chan.
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PAGE B-5
Method 204B - Volatile Organic Compound Emissions in
Captured Stream
1. INTRODUCTION
1.1 Applicability. This procedure is applicable for determining the volatile organic
compounds (VOC) content of captured gas streams. It is intended to be used in the development of
liquid/gas or gas/gas protocols for determining VOC capture efficiency (CE) for surface coating and
printing operations. The procedure may not be acceptable in certain site-specific situations, e.g.,
when: (1) direct-fired heaters or other circumstances affect the quantity of VOC at the control device
inlet: and (2) paniculate organic aerosols are formed in the process and are present in the captured
emissions.
1.2 Principle. The amount of VOC captured (G) is calculated as the sum of the products of
the VOC content (C^j), the flow rate (QQJ), and the sample time (0^) from each captured emissions
point.
1.3 Estimated Measurement Uncertainty. The measurement uncertainties are estimated for
each captured or fugitive emissions point as follows: QQ-. - ±5.5 percent and CQ; = ±5.0 percent.
Based on these numbers, the probable uncertainty for G is estimated at about ±7.4 percent.
1.4 Sampling Requirements. A capture efficiency test shall consist of at least three sampling
runs. Each run shall cover at least one complete production cycle but shall be at least 3 hours long.
The sampling time for each run need not exceed 8 hours even if the production cycle has not been
completed. Alternative sampling time* may be used with the approval of the Administrator.
1.5 Notes. Because this procedure is often applied in highly explosive areas, caution and care
should be exercised in choosing appropriate equipment and installing and using the equipment.
Mention of trade names or company products does not constitute endorsement. All gas concentrations
(percent, ppm) are by volume, unless otherwise noted.
2. APPARATUS AND REAGENTS
2.1 Gas VOC Concentration. A schematic of the measurement system is shown in
Figure 204B-1. The main components are as follows:
-------
a
m
oo
T.INC.IL
WH1E A1
r IHICT
SAMTI t
SAMIlE BYPASS
rn FxitAtisr
IKIIAMIlllll
irAim
PAH IICIII All:
III DM
-II
i_r
CAIIHTMIION
VAl VF
ASSEMMY IIFAIEP SAMTIC LINE
F
KINI/AIIDN
ANivmcn
SAMTlfc MAMKJIO
IEGEND
NtECXE VALVE
SAMPIE IINES
SIGNAL IINES
figure 204B-I. Gas VOC concentration measurement system.
-------
PAGE B-7
2.1.1 Sample Probe. Stainless steel, or equivalent. The probe shall be heated to prevent
VOC condensation.
2.1.2 Calibration Valve Assembly. Three-way valve assembly at the outlet of the sample
probe to direct the zero and calibration gases to the analyzer. Other methods, such as quick-connect
lines, to route calibration gases to the outlet of the sample probe are acceptable.
2.1.3 Sample Line. Stainless steel or Teflon tubing to transport the sample gas to the
analyzer. The sample line must be heated to prevent condensation.
2.1.4 Sample Pump. A leak-free pump, to pult the sample gas through the system at a flow
rate sufficient to minimize the response time of the measurement system. The components of the
pump that contact the gas stream shall be constructed of stainless steel or Teflon. The sample pump
must be heated to prevent condensation.
2.1.5 Sample Flow Rate Control. A sample flow rate control valve and rotameter. or
equivalent, to maintain a constant sampling rate within 10 percent. The flow rate control valve and
rotameter must be heated to prevent condensation. A control valve may also be located on the sample
pump bypass loop to assist in controlling the sample pressure and flow rate.
2.1.6 Sample Gas Manifold. Capable of diverting a portion of the sample gas stream to the
flame ionization analyzer (FIA), and the remainder to the bypass discharge vent. The manifold
components shall be constructed of stainless steel or Teflon. If captured or fugitive emissions are to
be measured at multiple locations, the measurement system shall be designed to use separate sampling
probes, lines, and pumps for each measurement location and a common sample gas manifold and
FIA. The sample gas manifold and connecting lines to the FIA must be heated to prevent
condensation.
2.1.7 Organic Concentration Analyzer. An FIA with a span value of 1.5 times the expected
concentration as propane; however, other span values may be used if it can be demonstrated to the
Administrator's satisfaction-that they would provide more accurate measurements. The system shall
be capable of meeting or exceeding the following specifications:
2.1.7.1 Zero Drift. Less than ±3.0 percent of the span value.
2.1.7.2 Calibration Drift. Less than ±3.0 percent of the span value.
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PAGE B-8 ; ^^
2.1.7.3 Calibration Error. Less than ±5.0 percent of the calibration gas value.
2.1.7.4 Response Time. Less than 30 seconds.
2.1.8 Integrator/Data Acquisition System. An analog or digital device or computerized data
acquisition system used to integrate the FIA response or Compute the average response and record
measurement data. The minimum data sampling frequency for computing average or integrated
values is one measurement value every 5 seconds. The device shall be capable of recording average
values at least once per minute.
2.1.9 Calibration and Other Gases. Gases used for calibration, fuel, and combustion air (if
required) are contained in compressed gas cylinders. All calibration gases shall be traceable to
National Institute of Standards and Technology standards and shall be certified by the manufacturer to
± 1 percent of the tag value. Additionally, the manufacturer of the cylinder should provide a
recommended shelf life for each calibration gas cylinder over which the concentration does not change
more than ±2 percent from the certified value. For calibration gas values not generally available.
alternative methods for preparing calibration gas mixtures, such as dilution systems, may be used with
the approval of the Administrator.
2.1.9.1 Fuel. A 40 percent H2/60 percent He or 40 percent H2/60 percent N2 gas mixture is
recommended to avoid an oxygen synergism effect that reportedly occurs when oxygen concentration
varies significantly from a mean value.
2.1.9.2 Carrier Gas. High purity air with less than 1 ppm of organic material (as propane or
carbon equivalent) or less than 0.1 percent of the span value, whichever is greater.
2.1.9.3 FIA Linearity Calibration Gases. Low-, mid-, and high-range gas mixture standards
with nominal propane concentrations of 20-30, 45-55, and 70-80 percent of the span value in air.
respectively. Other calibration values and other span values may be used if it can be shown to the
Administrator's satisfaction that more accurate measurements would be achieved.
2.1.10 Paniculate Filter. An in-stack or an out-of-stack glass fiber filter is recommended if
exhaust gas paniculate loading is significant. An out-of-stack filter must be heated to prevent any
condensation unless it can be demonstrated that no condensation occurs.
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PAGE B-9
2.2 Captured Emissions Volumetric Flow Rate.
2.2.1 Method 2 or 2A Apparatus. For determining volumetric flow rate.
2.2.2 Method 3 Apparatus and Reagents. For determining molecular weight of the gas
stream. An estimate of the molecular weight of the gas stream may be used if approved by the
Administrator.
2.2.3 Method 4 Apparatus and Reagents. For determining moisture content, if necessary.
3. DETERMINATION OF VOLUMETRIC FLOW RATE OF CAPTURED EMISSIONS
3.1 Locate all points where emissions are captured from the affected facility. Using Method
1. determine the sampling points. Be sure to check each site for cyclonic or swirling flow.
3.2 Measure the velocity at each sampling site at least once every hour during each sampling
run using Method 2 or 2A.
4. DETERMINATION OF VOC CONTENT OF CAPTURED EMISSIONS
4.1 Analysis Duration. Measure the VOC responses at each captured emissions point during
the entire test run or, if applicable, while the process is operating. If there are multiple captured
emission locations, design a sampling system to allow a single F1A to be used to determine the VOC
responses at all sampling locations.
4.2 Gas VOC Concentration.
4.2.1 Assemble the sample tra.n as shown in Figure 204B-1. Calibrate the FIA according to
the procedure in Section 5.1.
4.2.2 Conduct a system check according to the procedure in Section 5.3.
4.2.3 Install the sample probe so that the probe is centrally located in the stack, pipe, or duct,
and is sealed tightly at the stack port connection.
4.2.4 Inject zero gas at the calibration valve assembly. Allow the measurement system
response to reach zero. Measure the system response time as the time required for the system to
-------
PAGE B-10
reach the effluent concentration after the calibration valve has been returned to the effluent sampling
position.
4.2.5 Conduct a system check before and a system drift check after each sampling run
according to the procedures in Sections 5.2 and 5.3. If the drift check following a run indicates
unacceptable performance (see Section S.3), the run is not valid. The tester may elect to perform
system drift checks during the run not to exceed one drift check per hour.
4.2.6 Verify that the sample lines, filter, and pump temperatures are 120 ± 5°C.
4.2.7 Begin sampling at the start of the test period and continue to sample during the entire
run. Record the starting and ending times and any required process information as appropriate. If
multiple captured emission locations are sampled using a single FIA, sample at each location for the
same amount of time (e.g., 2 minutes) and continue to switch from one location to another for the
entire test run. Be sure that total sampling time at each location is the same at the end of the test run.
Collect at least four separate measurements from each sample point during each hour of testing.
Disregard the measurements at each sampling location until two times the response time of the
measurement system has elapsed. Continue sampling for at least 1 minute and record the
concentration measurements.
4.3 Background Concentration.
NOTE: Not applicable when the building is used as the temporary total enclosure (TTE).
4.3.1 Locate all natural draft openings (NDO's) of the TTE. A sampling point shall be at the
center of each NDO, unless otherwise specified by the Administrator. If there are more than six
NDO's, choose six sampling points evenly spaced among the NDO's.
4.3.2 Assemble the sample train as shown in Figure 204B-2. Calibrate the FIA and conduct a
system check according to the procedures in Sections 5.1 and 5.3. NOTE: This sample train shall
be a separate sampling train from the one to measure the captured emissions.
4.3.3 Position the probe a: the sampling location.
4.3.4 Determine the response time, conduct the system check and sample according to the
procedures described in Sections 4.2.4 to 4.2.7.
-------
HACK
PIM SSIIHt
HK.I MAI 011
II11 ON III AD
SAMIM I: I1IMP
ANAIY/tH
GAS IN IICI H»J
VAIV1
nOIAWEIERS
TIHUE
WAY
VAtVC S —
Figure 204B-1. Background measurement system,
•o
D
m
09
-------
PAGE B-12
4.4 Alternative Procedure. The direct interface sampling and analysis procedure described in
Section 7.2 of Method 18 may be used to determine the gas VOC concentration. The system must be
designed to collect and analyze at least one sample every 10 minutes.
5. CALIBRATION AND QUALITY ASSURANCE
5.1 FIA Calibration and Linearity Check. Make necessary adjustments to the air and fuel
supplies for the FIA and ignite the burner. Allow the FIA to warm up for the period recommended
by the manufacturer. Inject a calibration gas into the measurement system and adjust the back-
pressure regulator to the value required to achieve the flow rates specified by the manufacturer.
Inject the zero- and the high-range calibration gases and adjust the analyzer calibration to provide the
proper responses. Inject the low- and mid-range gases and record the responses of the measurement
system. The calibration and linearity of the system are acceptable if the responses for all four gases
are within 5 percent of the respective gas values. If the performance of the system is not acceptable.
repair or adjust the system and repeat the linearity check. Conduct a calibration and linearity check
after assembling the analysis system and after a major change is made to the system.
5.2 Systems Drift Checks. Select the calibration gas that most closely approximates the
concentration of the captured emissions for conducting the drift checks. Introduce the zero and
calibration gas at the calibration valve assembly and verify that the appropriate gas flow rate and
pressure are present at the FIA. Record the measurement system responses to the zero and
calibration gases. The performance of the system is acceptable if the difference between the drift
check measurement and the value obtained in Section S.I is less than 3 percent of the span value.
Conduct the system drift checks at the end of each run.
5.3 System Check. Inject the high range calibration gas at the inlet of the sampling probe and
record the response. The performance of the system is acceptable if the measurement system
response is within 5 percent of the value obtained in Section 5.1 for the high range calibration gas.
Conduct a system check before and after each test run.
5.4 Analysis Audit/ Immediately before each test, analyze an audit cylinder as described in
Section 5.2. The analysis audit must agree with the audit cylinder concentration within 10 percent.
6. NOMENCLATURE
A « area of NDO i, ft2.
total area of all NDO's in the enclosure, rr.
corrected average VOC concentration of background emissions at point i, ppm propane.
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PAGE B-13
= average background concentration, ppm propane.
= corrected average VOC concentration of captured emissions at point j, ppm propane.
CDH = average measured concentration for the drift check calibration gas. ppm propane.
CDQ = average system drift check concentration for zero concentration gas, ppm propane.
CH = actual concentration of the drift check calibration gas, ppm propane.
Cj = uncorrected average background VOC concentration measured at point i, ppm propane.
C: = uncorrected average VOC concentration measured at point j, ppm propane.
G = total VOC content of captured emissions, kg.
Kj = 1.830x 1CT6 kg/(m3-ppm).
n = number of measurement points.
= average effluent volumetric flow rate corrected to standard conditions at captured
emissions point j, rrr/rrin.
= total duration of captured emissions sampling run, min.
7. CALCULATIONS
7.1 Total VOC Captured Emissions.
n
;CGj - CB) QGj 6. Kj, Eq. 204B-1
7.2 VOC Concentration of the Captured Emissions at Point j.
C« • (C, - CpJ „ °" Eq. 204B-2
7.3 Background VOC Concentration at Point i.
C., * (C, - CM) „ °" Eq. 204B-3
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PAGE B-14
7.4 Average Background Concentration.
204B-4
NOTE: If the concentration at each point is within 20 percent of the average concentration of all
points, then use the arithmetic average.
-------
PAGEB-15
Method 204C - Volatile Organic Compound Emissions in
Captured Stream (Dilution Technique)
I. INTRODUCTION
1.1 Applicability. This procedure is applicable for determining the volatile organic compounds
(VOC) content of captured gas streams. It is intended to be used in the development of a gas/gas
protocol in which fugitive emissions are measured for determining VOC capture efficiency (CE) for
surface coating and printing operations. A dilution system is used to reduce the VOC concentration
of the captured emission to about the same concentration as the fugitive emissions. The procedure
may not be acceptable in certain site-specific situations, e.g., when: (1) direct fired heaters or other
circumstances affect the quantity of VOC at the control device inlet; and (2) paniculate organic
aerosols are formed in the process and are present in the captured emissions.
1.2 Principle. The amount of VOC captured (G) is calculated as the sum of the products of
the VOC content (Cgp, the flow rate (Qgj), and the sampling time (0C) from each captured
emissions point.
1.3 Estimated Measurement Uncertainty. The measurement uncertainties are estimated for
each captured or fugitive emissions point as follows: QQ: = ±5.5 percent and
C(]j = ±5 percent. Based on these numbers, the probable uncertainty for G is estimated at about
±7.4 percent.
1.4 Sampling Requirements. A capture efficiency test shall consist of at least three sampling
runs. Each run shall cover at least one complete production cycle but shall be at least 3 hours long.
The sampling time for each run need not exceed 8 hours even if the production cycle has not been
completed. Alternative sampling times may be used with the approval of the Administrator.
1.5 Notes. Because this procedure is often applied in highly explosive areas, caution and care
should be exercised in choosing appropriate equipment and installing and using the equipment.
Mention of trade names or-company products does not constitute endorsement. All gas concentrations
(percent, ppm) are by volume, unless otherwise noted.
2. APPARATUS AND REAGENTS
2.1 Gas VOC Concentration. A schematic of the measurement system is shown in
Figure 204C-1. The main components are as follows:
-------
SAMPIE
HYI'ASS
IIA
IKIIAUSI
OAIA
Ar.OHtSIIK)N
SVS1I M
r.iiAiir
IIIMKlN I
ISIII'I'IV I
OIIIMKlN
AMI
MOISMNIE
HfMOVAt
I
iivnnocAftnoNl
SCItlHIDEM I
ANAIY/IH
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VAIVU
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C AIH»I A] ION
GAS
M StACK
OMIIION
I'DOOE
coNinot
DEVICE
CAPTttflFD
EMISSIONS
Figure 204C-1. Captured ernksions measurement system.
-------
PAGES-17
2.1.1 Dilution System. A Kipp in-stack dilution probe and controller or similar device may
be used. The dilution rate may be changed by substituting different critical orifices or adjustments of
the aspirator supply pressure. The dilution system shall be heated to prevent VOC condensation.
Note: An out-of-stack dilution device may be used.
2.1.2 Calibration Valve Assembly. Three-way valve assembly at the outlet of the sample
probe to direct the zero and calibration gases to the analyzer. Other methods, such as
quick-connect lines, to route calibration gases to the outlet of the sample probe are acceptable.
2.1.3 Sample Line. Stainless steel or Teflon tubing to transport the sample gas to the
analyzer. The sample line must be heated to prevent condensation.
2.1.4 Sample Pump. A leak-free pump, to pull the sample gas through the system at a flow
rate sufficient to minimize the response time of the measurement system. The components of the
pump that contact the gas stream shall be constructed of stainless steel or Teflon. The sample pump
must be heated to prevent condensation.
2.1.5 Sample Flow Rate Control. A sample flow rate control valve and rotameter, or
equivalent, to maintain a constant sampling rate within 10 percent. The flow control valve and
rotameter must be heated to prevent condensation. A control valve may also be located on the sample
pump bypass loop to assist in controlling the sample pressure and flow rate.
2.1.6 Sample Gas Manifold. Capable of diverting a portion of the sample gas stream to the
flame ionization analyzer (FIA), and the remainder to the bypass discharge vent. The manifold
components shall be constructed of sta.nless steel or Teflon. If captured or fugitive emissions are to
be measured at multiple locations, the measurement system shall be designed to use separate sampling
probes, lines, and pumps for each measurement location and a common sample gas manifold and
FIA. The sample gas manifold and connecting lines to the FIA must be heated to prevent
condensation.
2.1.7 Organic Concentration Analyzer. An FIA with a span value of 1.5 times the expected
concentration as propane; however, other span values may be used if it can be demonstrated to the
Administrator's satisfaction that they would provide more accurate measurements. The system shall
be capable of meeting or exceeding the following specifications:
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PAGE B-18
2.1.7.1 Zero Drift. Less than ±3.0 percent of the span value.
2.1.7.2 Calibration Drift. Less than ±3.0 percent of the span value.
2.1.7.3 Calibration Error. Less than ±5.0 percent of the calibration gas value.
2.1.7.4 Response Time. Less than 30 seconds.
2.1.8 Integrator/Data Acquisition System. An analog or digital device or computerized data
acquisition system used to integrate the FIA response or compute the average response and record
measurement data. The minimum data sampling frequency for computing average or integrated
values is one measurement value every 5 seconds. The device shall be capable of recording average
values at least once per minute.
2.1.9 Calibration and Other Gases. Gases used for calibration, fuel, and combustion air (if
required) are contained in compressed gas cylinders. All calibration gases shall be traceable to
National Institute of Standards and Technology standards and shall be certified by the manufacturer to
± 1 percent of the tag value. Additionally, the manufacturer of the cylinder should provide a
recommended shelf life for each calibration gas cylinder over which the concentration does not change
more than ±2 percent from the certified value. For calibration gas values not generally available,
alternative methods for preparing calibration gas mixtures, such as dilution systems, may be used with
the approval of the Administrator.
2.1.9.1 Fuel. A 40 percent H2/60 percent He or
40 percent H2/60 percent N2 gas mixture is recommended to avoid an oxygen synergism effect that
reportedly occurs when oxygen concentration varies significantly from a mean value.
2.1.9.2 Carrier Gas and Dilution Air Supply. High purity air with less than 1 ppm of
organic material (as propane or carbon equivalent) or less than 0.1 percent of the span value,
whichever is greater.
2.1.9.3 FIA Linearity Calibration Gases. Low-, mid-, and high-range gas mixture standards
with nominal propane concentrations of 20-30, 45-55, and 70-80 percent of the span value in air,
respectively. Other calibration values and other span values may be used if it can be shown to the
Administrator's satisfaction that more accurate measurements would be achieved.
-------
PAGE B-19
2.1.9.4 Dilution Check Gas. Gas mixture standard containing propane in air, approximately
half the span value after dilution.
2.1.10 Particulate Filter. An in-stack or an out-of-stack glass fiber filter is recommended if
exhaust gas paniculate loading is significant. An out-of-stack filter must be heated to prevent any
condensation unless it can be demonstrated that no condensation occurs.
2.2 Captured Emissions Volumetric Flow Rate.
2.2.1 Method 2 or 2A Apparatus. For determining volumetric flow rate.
2.2.2 Method 3 Apparatus and Reagents. For determining molecular weight of the gas
stream. An estimate of the molecular weight of the gas stream may be used if approved by the
Administrator.
2.2.3 Method 4 Apparatus and Reagents. For determining moisture content, if necessary.
3. DETERMINATION OF VOLUMETRIC FLOW RATE OF CAPTURED EMISSIONS
3.1 Locate all points where emissions are captured from the affected facility. Using
Method 1, determine the sampling points. Be sure to check each site for cyclonic or swirling flow.
3.2 Measure the velocity at each sampling site at least once every hour during each sampling
run using Method 2 or 2A.
4. DETERMINATION OF VOC CONTENT OF CAPTURED EMISSIONS
4.1 Analysis Duration. Measure the VOC responses at each captured emissions point during
the entire test run or, if applicable, while the process is operating. If there are multiple captured
emissions locations, design a sampling system to allow a single FIA to be used to determine the VOC
responses at all sampling locations.
4.2 Gas VOC Concentration.
4.2.1 Assemble the sample train as shown in Figure 204C-1. Calibrate the FIA according to
the procedure in Section 5.1.
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PAGE B-20
4.2.2 Set the dilution ratio and determine the dilution factor according to the procedure in
Section 5.3.
4.2 J Conduct a system check according to the procedure in Section 5.4.
4.2.4 Install the sample probe so that the probe is centrally located in the stack, pipe, or duct,
and is sealed tightly at the stack port connection.
4.2.5 Inject zero gas at the calibration valve assembly. Measure the system response time as
the time required for the system to reach the effluent concentration after the calibration valve has been
returned to the effluent sampling position.
4.2.6 Conduct a system check before and a system drift check after each sampling run
according to the procedures in Sections 5.2 and 5.4. If the drift check following a run indicates
unacceptable performance (see Section 5.4), the run is not valid. The tester may elect to perform
system drift checks during the run not to exceed one drift check per hour.
4.2.7 Verify that the sample lines, filter, and pump temperatures are 120 ± 5°C.
4.2.8 Begin sampling at the start of the test period and continue to sample during the entire
run. Record the starting and ending times and any required process information as appropriate. If
multiple captured emission locations are sampled using a single FIA, sample at each location for the
same amount of time (e.g., 2 min.) and continue to switch from one location to another for the entire
test run. Be sure that total sampling time at each location is the same at the end of the test run.
Collect at least four separate measurements from each sample point during each hour of testing.
Disregard the measurements at each sampling location until two times the response time of the
measurement system has elapsed. Continue sampling for at least 1 minute and record the
concentration measurements.
4.3 Background Concentration.
NOTE: Not applicable when the building is used as the temporary total enclosure (TTE).
4.3.1 Locate all natural draft openings (NDO's) of the TTE. A sampling point shall be at the
center of each NDO, unless otherwise approved by the Administrator. If there are more than six
NDO's, choose six sampling points evenly spaced among the NDO's.
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PAGE B-21
4.3.2 Assemble the sample train as shown in Figure 204C-2. Calibrate the FIA and conduct a
system check according to the procedures in Sections 5.1 and 5.4.
4.3.3 Position the probe at the sampling location.
4.3.4 Determine the response time, conduct the system check and sample according to the
procedures described in Sections 4.2.4 :o 4.2.8.
4.4 Alternative Procedure. Hie direct interface sampling and analysis procedure described in
Section 7.2 of Method 18 may be used to determine the gas VOC concentration. The system must be
designed to collect and analyze at least one sample every 10 minutes.
5. CALIBRATION AND QUALITY ASSURANCE
5.1 FIA Calibration and Linearity Check. Make necessary adjustments to the air and fuel
supplies for the FIA and ignite the burner. Allow the FIA to warm up for the period recommended
by the manufacturer. Inject a calibration gas into the measurement system after the dilution system
and adjust the back-pressure regulator to the value required to achieve the flow rates specified by the
manufacturer. Inject the zero- and the high-range calibration gases and adjust the analyzer calibration
to provide the proper responses. Inject the low- and mid-range gases and record the responses of the
measurement system. The calibration and linearity of the system are acceptable if the responses for
all four gases are within 5 percent of the respective gas values. If the performance of the system is
not acceptable, repair, or adjust the system, and repeat the linearity check. Conduct a calibration and
linearity check after assembling the analysis system and after a major change is made to the system.
5.2 Systems Drift Checks. Select the calibration gas that most closely approximates the
concentration of the diluted captured emissions for conducting the drift checks. Introduce the zero
and calibration gas at the calibration valve assembly and verify that the appropriate gas flow rate and
pressure are present at the FIA. Record the measurement system responses to the zero and
calibration gases. The performance ot' the system is acceptable if the difference between the drift
check measurement and the"value obtained in Section 5.1 is less than 3 percent of the span value.
Conduct the system drift check at the end of each run.
5.3 Determination of Dilution Factor. Inject the dilution check gas into the measurement
system before the dilution system and record the response. Calculate the dilution factor using
Equation 204C-3.
-------
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UH ON lit AD
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VAIVt
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HOIAMtTtnS
lUULt
WAY
VAIVfcS
Figure 204C-2. Background measurement system.
-------
PAGE B-23
5.4 System Check. Inject the high range calibration gas at the inlet to the sampling probe
while the dilution air is turned off. Record the response. The performance of the system is
acceptable if the measurement system response is within 5 percent of the value obtained in Section 5.1
for the high range calibration gas. Conduct a system check before and after each test run.
5.5 Analysis Audit. Immediately before each test, analyze an audit cylinder as described in
Section 5.2. The analysis audit must agree with the audit cylinder concentration within 1 percent.
6. NOMENCLATURE
A{ = area of NDO i, ft2.
AN = total area of all NDO's in the enclosure, ft2.
C * = actual concentration of the dilution check gas, ppm propane.
Cgj = corrected average VOC concentration of background emissions at point i. ppm propane.
Cg = average background concentration, ppm propane.
average measured concentration for the drift check calibration gas, ppm propane.
average system drift check concentration for zero concentration gas, ppm propane.
actual concentration of the drift check calibration gas, ppm propane.
Cj = unconnected average background VOC concentration measured at point i, ppm propane.
C: = uncorrected average VOC concentration measured at point j, ppm propane.
measured concentration of the dilution check gas, ppm propane.
DF = dilution factor.
G = total VOC content of captured emissions, kg.
K! = 1.830x 10"6 kg/(m3-ppm).
n = number of measurement points.
= average effluent volumetric flow rate corrected to standard conditions at captured
emissions point j, irr/min.
= total duration of capture efficiency sampling run, min.
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PAGE B-24
7. CALCULATIONS
7.1 Total VOC Captured Emissions.
n
G » 2^ (CGJ ~ CB) QGJ #c ^i Eq. 204C—1
J-l
7.2 VOC Concentration of the Captured Emissions at Point j.
CH
CGj = DF (Cj - CDO) ___ Eq. 204C-2
J J Gnu Cnn *" «
"DH
7.3 Dilution Factor.
DF *
7.4 Background VOC Concentration at Point i.
C
7.5 Average Background Concentration.
n
_ a
Bi = (ci. " CDO) 7; ;T— Eq. 204C-^
CDH CDO
CBi kt
Eq. 204C-5
-------
PAGE B-25
NOTE: If the concentration at each point is within 20 percent of the average concentration of all
points, then use the arithmetic average.
-------
PAGE B-26
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PAGE B-27
Method 204D - Volatile Organic Compound Emissions in Fugitive
Stream from Temporary Total Enclosure
1. INTRODUCTION
1.1 Applicability. This procedure is applicable for determining the fugitive volatile organic
compounds (VOC) emissions from a temporary total enclosure (TTE). It is intended to be used as a
segment in the development of liquid/gas or gas/gas protocols for determining VOC capture efficiency
(CE) for surface coating and printing operations.
1.2 Principle. The amount of fugitive VOC emissions (F) from the TTE is calculated as the
sum of the products of the VOC content (CFj), the flow rate (QFj), and the sampling time (0F) from
each fugitive emissions point.
1.3 Estimated Measurement Uncertainty. The measurement uncertainties are estimated for
each fugitive emission point as follows: QFj = ±5.5 percent and CFj = ±5.0 percent. Based on
these numbers, the probable uncertainty for F is estimated at about ±7.4 percent.
1.4 Sampling Requirements. A capture efficiency test shall consist of at least three sampling
runs. Each run shall cover at least one complete production cycle but shall be at least 3 hours long.
The sampling time for each run need not exceed 8 hours even if the production cycle has not been
completed. Alternative sampling times may be used with the approval of the Administrator.
1.5 Notes. Because this procedure is often applied in highly explosive areas, caution and care
should be exercised in choosing appropriate equipment and installing and using the equipment.
Mention of trade names or company products does not constitute endorsement. All gas concentrations
(percent, ppm) are by volume, unless otherwise noted.
2. APPARATUS AND REAGENTS
2.1 Gas VOC Concentration. A schematic of the measurement system is shown in
Figure 204D-1. The main components are as follows:
2.1.1 Sample Probe. Stainless steel, or equivalent. The probe shall be heated to prevent
VOC condensation.
-------
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ii Aiort
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SAMPI K puma1
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GAS IN IICI ION
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EMISSION POINT I
FUGITIVE EMISSION TOINI 2
FUGITIVE EMISSION POIMI 3
FUGITIVE EMISSION POINT A
FUGITIVE EMISSION TOINT 5
o
m
w
Figure 204D-J. Fugitive emissions measurement system.
-------
^ PAGE B-29
2.1.2 Calibration Valve Assembly. Three-way valve assembly at the outlet of the sample
probe to direct the zero-and calibration gases to the analyzer. Other methods, such as quick-connect
lines, to route calibration gases to the outlet of the sample probe are acceptable.
2.1.3 Sample Line. Stainless steel or Teflon tubing to transport the sample gas to the
analyzer. The sample line must be heated to prevent condensation.
2.1.4 Sample Pump. A leak-free pump, to pull the sample gas through the system at a flow
rate sufficient to minimize the response time of the measurement system. The components of the
pump that contact the gas stream shall be constructed of stainless steel or Teflon. The sample pump
must be heated to prevent condensation.
2.1.5 Sample Flow Rate Control. A sample flow rate control valve and rotameter, or
equivalent, to maintain a constant sampling rate within 10 percent. The flow control valve and
rotameter must be heated to prevent condensation. A control valve may also be located on the sample
pump bypass loop to assist in controlling the sample pressure and flow rate.
2.1.6 Sample Gas Manifold. Capable of diverting a portion of the sample gas stream to the
flame ionization analyzer (FIA), and the remainder to the bypass discharge vent. The manifold
components shall be constructed of stainless steel or Teflon. If emissions are to be measured at
multiple locations, the measurement system shall be designed to use separate sampling probes, lines,
and pumps for each measurement location and a common sample gas manifold and FIA. The sample
gas manifold and connecting lines to the FIA must be heated to prevent condensation.
2.1.7 Organic Concentration Analyzer. An FIA with a span value of 1.5 times the expected
concentration as propane; however, other span values may be used if it can be demonstrated to the
Administrator's satisfaction that they would provide more accurate measurements. The system shall
be capable of meeting or exceeding th>; following specifications:
2.1.7.1 Zero Drift. Less than ±3.0 percent of the span value.
2.1.7.2 Calibration Drift. Less than ±3.0 percent of the span value.
2.1.7 J Calibration Error. Less than ±5.0 percent of the calibration gas value.
2.1.7.4 Response Time. Less than 30 seconds.
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PAGE B-30
2.1.8 Integrator/Data Acquisition System. An analog or digital device or computerized data
acquisition system used-to integrate the FIA response or compute the average response and record
measurement data. The minimum data sampling frequency for computing average or integrated
values is one measurement value every 5 seconds. The device shall be capable of recording average
values at least once per minute.
2.1.9 Calibration and Other Gases. Gases used for calibration, fuel, and combustion air (if
required) are contained in compressed gas cylinders. All calibration gases shall be traceable to
National Institute of Standards and Technology standards and shall be certified by the manufacturer to
± 1 percent of the tag value. Additionally, the manufacturer of the cylinder should provide a
recommended shelf life for each calibration gas cylinder over which the concentration does not change
more than ±2 percent from the certified value. For calibration gas values not generally available,
alternative methods for preparing calibration gas mixtures, such as dilution systems, may be used with
the approval of the Administrator.
2.1.9.1 Fuel. A 40 percent H2/60 percent He or
40 percent H2/60 percent N2 gas mixture is recommended to avoid an oxygen synergism effect that
reportedly occurs when oxygen concentration varies significantly from a mean value.
2.1.9.2 Carrier Gas. High purity air with less than 1 ppm of organic material (as propane or
carbon equivalent) or less than 0.1 percent of the span value, whichever is greater.
2.1.9.3 FIA Linearity Calibration Gases. Low-, mid-, and high-range gas mixture standards
with nominal propane concentrations of 20-30, 45-55, and 70-80 percent of the span value in air,
respectively. Other calibration values and other span values may be used if it can be shown to the
Administrator's satisfaction that more accurate measurements would be achieved.
2.1.10 Paniculate Filter. An in-stack or an out-of-stack glass fiber filter is recommended if
exhaust gas paniculate loading is significant. An out-of-stack filter must be heated to prevent any
condensation unless it can be demonstrated that no condensation occurs.
2.2 Fugitive Emissions Volumetric Flow Rate.
2.2.1 Method 2 or 2A Apparatus. For determining volumetric flow rate.
-------
PAGEB-31
122 Method 3 Apparatus and Reagents. For determining molecular weight of the gas
stream. An estimate of the molecular weight of the gas stream may be used if approved by the
Administrator.
223 Method 4 Apparatus and Reagents. For determining moisture content, if necessary.
23 Temporary Total Enclosure. The criteria for designing an acceptable TTE are specified
in Method 204.
3. DETERMINATION OF VOLUMETRIC FLOW RATE OF FUGITIVE EMISSIONS
3.1 Locate all points where emissions are exhausted from the TTE. Using Method 1,
determine the sampling points. Be sure to check each site for cyclonic or swirling flow.
3.2 Measure the velocity at each sampling site at least once every hour during each sampling
run using Method 2 or 2A.
4. DETERMINATION OF VOC CONTENT OF FUGITIVE EMISSIONS
4.1 Analysis Duration. Measure the VOC responses at each fugitive emission point during
the entire test run or, if applicable, while the process is operating. If there are multiple emission
locations, design a sampling system to allow a single FIA to be used to determine die VOC responses
at ail sampling locations.
4.2 Gas VOC Concentration.
4.2.1 Assemble the sample train as shown in Figure 204D-1. Calibrate the FIA and conduct a
system check according to the procedures in Sections S.I and 5.3, respectively.
422 Install the sample probe so that the probe is centrally located in the stack, pipe, or duct,
and is sealed tightly at the Stack port connection.
4.2.3 Inject zero gas at the calibration valve assembly. Allow the measurement system
response to reach zero. Measure the system response time as the time required for the system to
reach the effluent concentration after the calibration valve has been returned to the effluent sampling
position.
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PAGE B-32
4.2.4 Conduct a system check before and a system drift check after each sampling run
according to the procedures in Sections 5.2 and 5.3. If the drift check following a run indicates
unacceptable performance (see Section 5.3), the run is not valid. The tester may elect to perform
system drift checks during the run not to exceed one drift check per hour.
4.2.5 Verify that the sample lines, filter, and pump temperatures are 120 ± 5°C.
4.2.6 Begin sampling at the start of the test period and continue to sample during the entire
run. Record the starting and ending times and any required process information as appropriate. If
multiple emission locations are sampled using a single FIA, sample at each location for the same
amount of time (e.g., 2 min.) and continue to switch from one location to another for the entire test
run. Be sure that total sampling time at each location is the same at the end of the test run. Collect
at least four separate measurements from each sample point during each hour of testing. Disregard
the response measurements at each sampling location until two times the response time of the
measurement system has elapsed. Continue sampling for at least 1 minute and record the
concentration measurements.
4J Background Concentration.
4.3.1 Locate all natural draft openings (NDO's) of the TTE. A sampling point shall be at the
center of each NDO, unless otherwise approved by the Administrator. If there are more than six
NDO's, choose six sampling points evenly spaced among the NDO's.
4.3.2 Assemble the sample train as shown in Figure 204D-2. Calibrate the FIA and conduct a
system check according to the procedures in Sections 5.1 and 5.3.
4.3.3 Position the probe at the sampling location.
4.3.4 Determine the response time, conduct the system check and sample according to the
procedures described in
Sections 4.2.3 to 4.2.6.
4.4 Alternative Procedure. The direct interface sampling and analysis procedure described in
Section 7.2 of Method 18 may be used to determine the gas VOC concentration. The system must be
designed to collect and analyze at least one sample every 10 minutes.
-------
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Figure 204D-2. Background measurement system.
tn
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-------
PAGE B-34
5. CALIBRATION AND QUALITY ASSURANCE
5.1 FIA Calibration and Linearity Check. Make necessary adjustments to the air and fuel
supplies for the FIA and ignite the burner. Allow the FIA to warm up for the period recommended
by the manufacturer. Inject a calibration gas into the measurement system and adjust the back-
pressure regulator to the value required to achieve the flcv rates specified by the manufacturer.
Inject the zero- and the high-range calibration gases and adjust the analyzer calibration to provide the
proper responses. Inject the low- and mid-range gases and record the responses of the measurement
system. The calibration and linearity of the system are acceptable if the responses for all four gases
are within 5 percent of the respective gas values. If the performance of the system is not acceptable
repair or adjust the system, and repeat the linearity check. Conduct a calibration and linearity check
after assembling the analysis system and after a major change is made to the system.
5.2 Systems Drift Checks. Select the calibration gas concentration that most closely
approximates that of the fugitive gas emissions to conduct the drift checks. Introduce the zero and
calibration gas at the calibration valve assembly and verify that the appropriate gas flow rate and
pressure are present at the FIA. Record the measurement system responses to the zero and
calibration gases. The performance of the system is acceptable if the difference between the drift
check measurement and the value obtained in Section 5.1 is less than 3 percent of the span value.
Conduct a system drift check at the end of each run.
5.3 System Check. Inject the high range calibration gas at the inlet of the sampling probe and
record the response. The performance of the system is acceptable if the measurement system
response is within 5 percent of the value obtained in Section 5.1 for the high range calibration gas.
Conduct a system check before each test run.
5.4 Analysis Audit. Immediately before each test, analyze an audit cylinder as described in
Section 5.2. The analysis audit must agree with the audit cylinder concentration within 10 percent.
6. NOMENCLATURE
Aj = area of NDOi, ft2.
AN = total area of all NDO's in the enclosure, ft2.
CBi = corrected average VOC concentration of background emissions at point i, ppm propane.
CB = average background concentration, ppm propane.
CDH =» average measured concentration for the drift check calibration gas, ppm propane.
CDO = average system drift check concentration for zero concentration gas, ppm propane.
CFj = corrected average VOC concentration of fugitive emissions at point j, ppm propane.
-------
PAGE B-35
CH = actual concentration of the drift check calibration gas, ppm propane.
C; = uncorrected average background VOC concentration at point i, ppm propane.
C = uncorrected average VOC concentration measured at point j, ppm propane.
F = total VOC content of fugitive emissions, kg.
K, = 1.830 x 10-* kg/(m3-ppm).
n = number of measurement points.
QFj = average effluent volumetric flow rate corrected to standard conditions at fugitive
missions point j, m3/min.
6F = total duration of fugitive emissions sampling run, min.
7. CALCULATIONS
7.1 Total VOC Fugitive Emissions.
n
F - E
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PAGE B-36
NOTE: If the concentration at each point is within 20 percent of the average concentration of all
points, then use the arithmetic average.
-------
APPENDIX C
SAFETY AND HEALTH CONSIDERATIONS
-------
PAGE C-l
SAFETY AND HEALTH CONSIDERATIONS
In any workplace where volatile organic compounds (VOC's) are used, care must be taken to
maintain a healthful and safe atmosphere. These considerations are paramount when designing and
operating a temporary total enclosure (TTE), which, after all, is constructed for the express purpose
of containing the VOC's generated within it. Fortunately, the hazards presented by using a TTE are
no different from those encountered in any setting where VOC's are used, and industrial hygiene
practices for worker protection are well established.
There are two potential hazards associated with gaseous VOC's: worker health effects and
fire. These areas of concern are discussed below.
WORKER HEALTH PROTECTION
A much lower ambient VOC concentration must be maintained to protect worker health than
to protect against fire. Thus, in any TTE that workers must enter, health protection considerations
predominate.
Allowable Exposure Levels
To protect the health of the worker, the Occupational Safety and Health Administration
(OSHA) has established maximum acceptable exposure levels for many substances, including most of
the commonly used solvents. The Permissible Exposure Limit (PEL) for a substance is the maximum
time-weighted average airborne concentration to which a worker may be exposed in any 8-hour work
shift of a 40-hour work week. For solvents, PEL's range typically between 50 and 1.000 parts per
million by volume (ppmv).
For some substances, in addition to a PEL, OSHA has set a Short Term Exposure Limit
(STEL). The STEL is the maximum 15-minute, time-weighted average concentration to which a
worker may be exposed at any time during a work day. (Some STEL's specify other averaging
periods.) For those solvents for which an STEL has been established, the STEL is typically about SO
percent higher than the REL.
For some substances, OSHA has set ceiling levels, which are never to be exceeded for any
time period. Ceilings are primarily established for acutely toxic materials; these substances generally
are not subject to a PEL or STEL. Ceilings have been set for very few common solvents.
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PAGE C-2
The PEL'S, STEL's, and ceilings established by OSHA, as well as other pertinent
information, are located-in the Code of Federal Regulations, Title 29, Part 1910 (29 CFR 1910).
Listings for over 600 substances can be found at 29 CFR 1910.1000. Other substances are regulated
individually.
For a mixture of VOC's, OSHA and industrial hygiene practice dictate that the effects of the
various component compounds be considered as additive. ^ This means that the PEL for a mixture
of compounds has been reached when the following equation is satisfied. -^
(Equation 1)
where:
Cj, C2, ..., Cn = the individual concentrations of the compounds that make up
the mixture, ppmv
PEL], PEL2, ..., PELn = the individual PEL's of the compounds that makeup the
mixture, ppmv
The atmosphere is below the PEL for the mixture when the sum is less than one.
Sizing the Temporary Exhaust System
The temporary exhaust system installed to draw the fugitive emissions out of a TTE for
measurement must be designed to keep the VOC concentration in the enclosure at healthful levels.
The system must be sized so that the air that enters the enclosure to replace the air exhausted by the
temporary exhaust system is sufficient to dilute the VOC's that are not captured by the permanent
capture device(s) to below the PEL. The rate at which this dilution air enters the TTE is equal to the
temporary exhaust rate.
Unfortunately, to calculate the necessary temporary exhaust rate accurately, some of the very
information that is to be gathered during the capture efficiency (CE) test is needed. As a result, the
appropriate temporary exhaust rate must be estimated. To ensure the safety of the workers, the
-------
_ PAGE C-3
estimate should be based on conservative assumptions. For the test, a temporary exhaust system with
a variable flowrate is advisable, and the VOC concentration in the TTE should be monitored.
There are two basic methods for estimating the temporary exhaust rate that is needed to
maintain a healthful atmosphere inside the TTE: the Grumpier Chart method and the calculation
method. The accuracy of each method relies on an accurate estimate of one of the parameters that is
to be measured subsequently. The selection between the methods often hinges on the information that
is available about the process in question and its emissions.
The Crwnpler Chart Method
This approach to estimating the necessary temporary exhaust rate is included in Method 204
(see Appendix B). It is especially useful when test data from the process are available.
The Grumpier Chart (see Figure C-l) illustrates the relationship among five parameters: the
VOC concentration in the captured gas stream (CG), the VOC concentration in the temporary exhaust
stream (Cp), the volumetric flowrate of the captured gas stream (QQ), the volumetric flowrate of the
temporary exhaust stream (Qp), and the CE. The chart is based on the following equation:
CE = G G (Equation 2a)
which can be rearranged to the form
^L = 1-CE x ££ (Equation 2b)
QG CE cF
where:
CE = capture efficiency, dimensionless
Cp = the VOC concentration in the temporary exhaust stream (i.e., the fugitive
emissions), ppmv
CQ = the VOC concentration in the captured gas stream (i.e., the captured emissions),
ppmv
Qp = the volumetric flowrate of the temporary exhaust stream corrected to standard
conditions of 68CF and 29.92 inches of mercury (in. Hg), standard cubic feet per
minute (scfm)
-------
PAGE C-4
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0.80
0.70
0.60
0.50
0.02 -
0.01
0.5 1.0 1.5 2.0 2.5 3.0
Volumetric Flov/rate of Fugitive Emissions Exhaust Stream
3.5
QF
Volumetric Flowrate of Gas Stream Delivered to the Control Device QG~
Figure C-l. The crumpler chart.
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PAGE C-S
QQ = the volumetric flowrate of the captured gas steam, scrrn
(Because the units cancel, the concentrations and flowrates actually can be in any units, provided they
are consistent.)
The Grumpier Chan method uses test data from the captured gas stream to estimate the
necessary temporary exhaust rate. Often, such data are available from a previous test of control
device efficiency. Alternatively, a test can be conducted specifically for this purpose. In either case,
the VOC concentration and volumetric flowrate of the captured gas stream (€Q and QQ, respectively)
are known from the test results. The desired VOC concentration in the temporary exhaust stream
(Cp) can be selected based on the PEL. Using an estimated value for the CE, the necessary
temporary exhaust rate (Qp) can be determined from the Grumpier Chart or from Equation 2b.
EXAMPLE 1.
An industrial fabric coating operation is to be tested for CE. The coating line applies a
rubber coating in which toluene is the only VOC, The test report from a previous control device
efficiency test conducted at the maximum normal production rate indicates that the average toluene
concentration at the inlet to the control device during the test was 984 ppmv and the average
volumetric flowrate was 6,159 scfin. What temporary exhaust rate should be used for the CE test?
Solution. The values ofCG (984 ppmv) and QQ (6,159 scfin) are given in the test report. In order
to use the Grumpier Chart, values for Cpand CE also must be determined. Typically, Cp is
assigned the value of the VOC's PEL,' the PEL for toluene is 100 ppmv. Based on an inspection of
the facility, the CE is estimated to be 80 percent. This value is believed to be conservatively low
because the flashoffarea between the coating applicator and the entrance to the drying oven is very
short and because the drying oven is operated at negative pressure so that very little, if any, of the
VOC emitted within the oven escapes.
The use of the Crumpler Chart is illustrated in Figure C-L First, the value ofCfJCG is
determined and located on the y-axis of the chart. In this case, CflCG is equal to 100/984, or
approximately 0.10. Point A in Figure C-l represents this step.
From Point A, a line is drawn parallel to the x-axis until it intersects the curve that
represents the estimated CE value. The intersection point is designated as Point B in Figure C-l.
From Point B, a line is drawn downward, parallel to the y-axis, until it intersects the x-axis.
Point C represents the intersection point in Figure C-l. The value at Point C is read from the
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PAGE C-6
x-axis. In this case, the value, which is equal to Q^QQ, is approximately 2.5. Thus, QF is equal
to 2.5 x 6,159, or about 15,400 scfm.
In the example above, it is assumed that the process operates at close to standard conditions
(i.e., 68°F and 29.92 in. Hg) so that the volume determined in scfm can be used without adjusting
for temperature or pressure. However, when the expected conditions vary significantly from standard
conditions, the temporary exhaust rate should be adjusted to reflect the difference. As a general rule
of ventilation system design, no corrections are necessary between the temperatures of 40 and 100CF
and at elevations within 1,000 feet of sea level.3 Outside these ranges, the temporary exhaust rate in
scfm should be convened to actual cubic feet per minute (acfm). The adjustment is made by
multiplying the volume calculated in scfm by the ratio of absolute temperatures and by the ratio of
standard pressure to the actual pressure:
acfm * scfm x
460 + 68 F actual in. Hg
When using the Grumpier Chart method, it is important to use conservative assumptions in
the CE estimate, the target temporary exhaust VOC concentration (Cp), or both. When the PEL for
the VOC is used as the value of Cp, the resulting temporary exhaust rate is such that the
concentration in the exhaust duct will equal the PEL if the CE has been accurately estimated. The
temporary exhaust stream concentration reflects the average concentration within the TTE, but,
because of imperfect mixing, there is no guarantee that the concentration in the breathing zone of the
workers will be at or below the PEL under these circumstances.
Generally, the TTE can be designed to keep the concentration in the breathing zone below the
PEL by strategically locating the natural draft openings and exhaust system intake, but in some cases,
process and spatial constraints may interfere with the desired design. In addition, the Grumpier Chan
method does not account for any background VOC content in the makeup air that enters the
enclosure. Thus, it is advisable to allow for a margin of safety when estimating the CE and selecting
the target value for the temporary exhaust stream VOC concentration. For more information on
safety factors and background VOC concentration adjustments, see the section on the calculation
method for sizing the temporary exhaust system.
A complication in using the Grumpier Chart method can result from the fact that VOC
concentration measurements typically are expressed in terms of a reference gas (e.g., "as propane"),
rather than in terms of the actual compound(s) in use. To use the Grumpier Chart, the reported
reference compound value must be converted to the corresponding value for the actual compound(s)
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PAGE C-7
based on the measurement principle of the method used to measure the VOC concentration.
Alternatively, the value selected for Cp can be converted to the corresponding value for the reference
compound. See the section on monitoring considerations for information on converting flame
ionization analyzer readings in terms of a reference gas to concentration in terms of the actual
compound(s).
Such conversions can be especially troublesome when a VOC mixture is used. In such cases,
it may be advisable to size the temporary exhaust system as if the entire mixture consisted of the
single most restrictive VOC in the mixture. This assumption greatly simplifies the process of
estimating the necessary temporary exhaust rate and provides a margin of safety to the extent that the
other components in the VOC mixture require less dilution air. However, this simplification may
result in a much higher temporary exhaust rate than necessary if the selected VOC is much more
restrictive than the other components and comprises a small fraction of the mixture. For information
on determining which VOC in a mixture is the most restrictive, see the section on monitoring
considerations where the analogous simplifying assumption for monitoring is discussed.
The preceding discussion of the Grumpier Chan method has been based on the use of test data
from the captured gas stream. The method also can be used when test data are not available if there
is adequate information with which to estimate the VOC concentration and volumetric flowrate of the
captured gas stream. Again, in cases where multiple VOC's are used, basing the estimation on the
most restrictive component greatly simplifies the process and provides a margin of safety. To
determine the most restrictive VOC in the mixture for this purpose, see Expression A in the section
on the calculation method where the analogous simplifying assumption is discussed.
The Calculation Method
To use this method to estimate the necessary temporary exhaust rate, the first step is to
estimate the fugitive emission rate that will prevail during the CE test. This fugitive emission rate
should be estimated using the best available data, such as past CE tests, other emission tests, material
balances, etc. In addition, the background VOC concentration must be estimated if it is significant.
The likeliest source of information on which to base background estimates is the facility's OSHA
compliance monitoring. An alternative is to take measurements around the periphery of the process
area using a portable instrument during the pretest plant visit.
Single VOC. Using the estimated fugitive emission rate, the exhaust rate for a process that
uses a single VOC can be calculated using Equation 4 below. This equation is based on standard
temperature and pressure as defined in EPA Method 2, i.e., 68°F and 29.92 in. Hg. As discussed
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PAGE C-8
previously in the section on the Grumpier Chart method, the temporary exhaust rate must be adjusted
using Equation 3 if the actual temperature or pressure differ significantly from standard conditions.
n 385 x p x ER x K
*< * T~Z (Equation 4)
(PEL - CB ) x 10 6 x MW '
where:
Q = temporary exhaust rate, scfm
385 = the volume occupied by 1 pound-mole (Ib-mol) of an ideal gas at standard conditions.
standard cubic feet (std. ft3) VOC/lb-mol
p = the density of the liquid VOC, pounds per gallon (Ib/gal)
ER = the fugitive emission rate in terms of the amount of liquid VOC evaporating, gallons
per minute (gal/min)
K = a safety factor to allow for incomplete mixing, dimensionless
PEL - the PEL for the gaseous VOC, ppmv
CB = the background concentration of the VOC in the dilution air entering the enclosure,
ppmv
10"6 = a factor to adjust for the fact that the PEL and Cg unit "ppmv" is actually "std. ft3
VOC/106 std. ft3 total gas" (i.e., air plus VOC)
MW = the molecular weight of the VOC, Ib/lb-mol
(When the fugitive emission rate [ER] .s more readily estimated as a mass emission rate, the value in
terms of Ib/min can be used in Equation 4, and the density of the VOC [p] can be omitted.)
The safety factor, K, ranges between 1 and 10. It is selected based on a judgement of site-
specific conditions. The considerations that enter into the selection of the K value include the
efficiency of mixing and the distribution of the dilution air entering the TTE, the toxicity of the VOC,
and other factors that may affect worker exposure, such as the duration of the process, the location of
the workers relative to the VOC sources, and how long the workers remain inside the TTE.4 The
following factors contribute-to a lower K value (and lower temporary exhaust rate):
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PAGE C-9
• Good mixing and distribution of dilution air
• VCX; "swept" away from workers' breathing zone (to minimize worker exposure, the
ideal configuration has the dilution air introduced behind the worker and then passing
through the breathing zone, over the VOC emission points, and out through the exhaust)
• VOC with low toxicity (generally associated with higher PEL's)
• Workers inside the TIE for short periods
• Other conditions that result in a low VOC concentration in the workers' breathing zone
Consult Reference 4 for additional guidance on selecting a K. value. A well designed TTE (with
natural draft openings and fugitive exhaust positioned to provide good mixing and "sweep" the work
area) should have a low K value, especially in cases where workers remain inside for only short
periods.
EXAMPLE 2.
An industrial fabric coating operation is to be tested for CE. The coating line applies a
rubber coating that consists of 35 percent solids by volume and 65 percent toluene by volume as
applied. Using the results of a previous control device efficiency test conducted at the maximum
normal production rate, it is determined that approximately 87 Ib/hr of toluene are vented to the
inlet of the control device. Under these process conditions, the line applies about 20 galfhr of
coating. Ambient testing for OSHA compliance purposes indicates that the background
concentration of toluene is about 20 ppmv. What temporary exhaust rate should be used for the
CE test?
Solution. This coating operation uses a single VOC, toluene. The pertinent parameters for toluene
are as follows:
P =7.21 Ib/gal
PEL = 100 ppmv
MW = 92.131b/lb-mol
The first step is to estimate the fugitive emission rate of toluene. The total amount of toluene
applied per hour on the coating line is calculated as indicated below:
20 gal coating/hr x 0.65 toluene/gal coating « 13 gal toluene/hr
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PAGE C-10
The amount of toluene vented to the control device (i.e., captured) per hour is found as follows:
87 Ib toluene/hr
7.21 Ib toluene/gal toluene
12 gal toluene/hr
The approximate toluene fugitive emission rate is the difference between the amount applied and
the amount captured:
ER m 13 gal/hr - 12 gal/hr m Q QIJ n
60 min/hr
After the fugitive emission rate has been estimated, the only missing parameter in Equation 4 is the
safety factor, K. For this example, a K value of 4 is selected. This value is based on the relatively
high toxicity of toluene (PEL - lOOppmv) and on the assumption that the TTE has been well
designed for good mixing and distribution of the dilution air but that the workers spend much of
the time inside the TTE in fairly close proximity to the coating applicator where the fugitive
emissions are generated.
Now that values have been assigned to all the parameters, the temporary exhaust rate can be
calculated using Equation 4:
385 x 7.21 x 0.017 x 4
(100 - 20) x 10~6 x 92.13
* 25,600 scfm
If the process operates at conditions significantly different from standard conditions, the temporary
exhaust rate should be adjusted using Equation 3.
As discussed earlier in the section on the Grumpier Chart method, the mass flow rates
presented in test reports are typically in terms of a reference compound (e.g., "as propane") rather
than in terms of the actual compound(s) in use. For a discussion of conversions from a reference
compound value to the corresponding value for the actual compound(s) when a flame ionization
analyzer is used (EPA Method 25A), see the section on monitoring considerations. The same
considerations may apply to background VOC concentration measurements.
Mixture of VOC's. To calculate the total temporary exhaust rate required for a mixture of
VOC's, the fugitive emission rate and background concentration for each component are estimated,
and the temporary exhaust rate necessary for each is calculated using Equation 4 above. The sum of
the exhaust rates for the individual components is the total temporary exhaust rate that is needed.
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PAGE C-11
EXAMPLE 3.
A multiple-station packaging rotogravure press is to be tested for CE. Under the production
conditions planned for the test, the inks applied by the press in 1 hr contain approximately 1 gal of
toluene, 5 gal ofisopropyl acetate, and 17 gal ofethanol (A simplified, three-solvent system is
used here for purposes of illustration.) A previous test using liquid/gas material balancing
techniques indicated that the CEfor the press is about 80 percent. Background concentrations are
estimated at S ppmv toluene, 15 ppmv isopropyl acetate, and 45 ppmv ethanol. What temporary
exhaust rate should be used for the CE test?
Solution. The pertinent parameters for the three VOC's are as follows:
p, Ib/gal PEL, ppmv MW, Ib/lb-mol K
Toluene 7.21 100 92.13 1
Isopropyl acetate 7.27 250 102.13 1
Ethanol 6.57 1,000 46.07 1
The K values were assigned based on a TTE that has been well designed to provide good mixing
and distribution of the dilution air in a configuration that sweeps the fugitive emissions from the
workers' breathing zone. It is further assumed that the workers will only occasionally enter the
TTE for a few minutes at a time to make minor adjustments. Under such optimum conditions, K
values ofl can be justified despite the relatively low PEL's of toluene (100 ppmv) and isopropyl
acetate (250 ppmv). However, even under these favorable circumstances, the interior of the TTE
should be monitored during testing to ensure that the STEL'sfor toluene (150 ppmv) and isopropyl
acetate (310 ppmv) are not violated.
Based on the previous CE test, approximately 20 percent of the input VOC's are released as fugitive
emissions. This percentage amounts to about 0.2 gal/hr of toluene, 1 gal/hr ofisopropyl acetate,
and 3.4 gal/hr ofethanol. The volume of dilution air needed for each VOC is calculated below
using Equation 4 (with a factor of 60 min/hr added to the denominator to convert the fugitive
emission rates listed above into terms ofgal/min):
Toluene Q - 385 X 7'21 x °'2 x 1
(100-5) x 10'6 x 92.13 x 60
1,100 scfm
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PAGE C-12
T , . » n 385 x 7:27 x
Isopropyl acetate Q
Ethanol Q
(250-15) x 10"6 x 102.13 x 60
- 1,900 scfm
» 385 x 6.57 x 3.4 x 1
(1,000-45) x 10"6 x 46.07 x 60
* 3,300 scfm
The total temporary exhaust rate necessary for proper dilution is the sum of the rates calculated for
each constituent VOC. For this example, the total is approximately 6,300 scfm. If the temperature
or pressure differ significantly from standard conditions, the temporary exhaust rate could be
adjusted using Equation 3.
A simpler approach may be taken for a VOC mixture. The temporary exhaust rate may be
calculated assuming that the entire mixture is composed of the single component that requires the
greatest quantity of dilution air per unit liquid volume. This component is the one that has the largest
value for the following expression:
(PEL-OB) ^ MW (Expression A)
where the symbols have the meanings defined for Equation 4. (When the fugitive emission rate [ER]
has been estimated in terms of Ib/min, the density of the VOC \p] can be omitted from Expression A
to determine which component requires the greatest quantity of dilution air per unit mass.) However,
as demonstrated in the following example, this approach can result in a much higher exhaust rate than
actually is necessary.
EXAMPLE 4.
For the multiple-station packaging rotogravure press presented in Example 3, it is not
known what product will be being printed during the CE test. The same three VOC's (toluene,
isopropyl acetate, and ethanol) are used in the inks for all products, but the relative quantities vary
with the product being printed. The maximum VOC application rate is known to be about
23 gal/hr. What temporary exhaust rate should be used for the CE test to ensure a healthful
atmosphere inside the TTE?
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^ _ PAGE C-13
Solution. To determine which VOC to base the temporary exhaust rate on, calculate the value of
Expression A (presented above) for each of the known constituents:
Isopropyl acetate 1Q2 B - -0.0003
6.57 x 1
Ethanol - _ _ — - - __ - - 0.0001
(1,000 - 45) x 46.07
Because the value for toluene is the largest, the temporary exhaust rate is calculated assuming that
the entire VOC mixture is composed of toluene. Assuming that approximately 20 percent of the
total 23 gal/hr of VOC's escapes as fugitive emissions (based on an earlier liquid/gas material
balance CE test as presented in Example 3), the fugitive emission rate is about 4.6 gal/hr. Using
Equation 4 (with a factor of 60 in the denominator to convert the emission rate to gal/min), the
temporary exhaust rate is calculated as follows:
n 385 x 7.21 x 4.6 X 1
(100-5) x 10~6 x 92.13 x 60
24,300 scfm of air
If the actual temperature or pressure differ significantly from standard conditions, the temporary
exhaust rate should be adjusted using Equation 3.
Monitoring Considerations for Heath Protection
Because the temporary exhaust rate is determined based on an estimation of the fugitive
emission rate, it is advisable to ensure that healthful concentration levels are maintained within the
enclosure during testing. The instrument measuring the VOC concentration in the temporary exhaust
stream is, in effect, a continuous monitor of the average concentration in the TIE. However,
periodic monitoring of concentrations in the breathing zone of the workers is advisable to identify any
"hot spots" within the TTE.
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PAGE C-14
The TTE and exhaust system should be designed and operated to maintain VOC
concentrations at or betew the PEL in both the temporary exhaust stream and the breathing zone of
the workers. However, remember that the PEL is an 8-hour, time-weighted average, so short-term
excursions above the PEL in the breathing zone can be tolerated as long as they are balanced by
periods below the PEL. Infrequent readings above the PEL need not result in an immediate cessation
of testing and removal of the TTE. Of course, for compounds for which an STEL or ceiling has been
set, the VOC concentration must not violate these limits.
Monitoring VOC concentrations is complicated by the fact that the monitors typically are not
calibrated with the actual compounds that are in use. For example, according to Method 204D (see
Appendix B), the VOC concentration in the temporary exhaust stream is to be measured using a flame
ionization analyzer (FIA) calibrated with propane. In most cases, the TTE interior is monitored using
a sampling line connected to this FIA or to the FIA used to take background readings (also calibrated
with propane). Thus, to track worker exposure, one must be able to translate FIA readings "as
propane" into the concentrations of the actual compounds being used. Fortunately, the FIA
translation can be made with reasonable accuracy provided the identities and relative amounts of the
compounds are known.
The FIA works essentially by breaking down organic compounds and counting the carbon
atoms. However, the counting is affected by the types of bonds and the noncarbon atoms in the
molecule. Therefore, to predict the response an FIA will have to a given compound, the "effective
carbon number" (ECN) is used.
For the type of FIA used for source testing, Table C-l presents one set of parameters that can
be used to calculate the ECN for a compound within about ±20 percent. To use this table, first
assign each carbon atom in the compound a value based on the type of bonds it is involved in, then
modify this value by the indicated amount for each noncarbon atom bonded to it. The ECN for the
compound is the sum of the modified values for all the carbons. To illustrate the use of Table C-l,
the ECN's for a few VOC's are derived in Figure C-2.
Experimental results for many compounds and more refined approaches to predicting FIA
responses can be found in the scientific literature, such as References 6, 7, and 8. Other possible
sources of data on FIA response include data from the instrument manufacturer and experimental data
generated in advance of the test by exposing the instrument to known concentrations of the
compounds of interest. Note that portable, hand-held FIA's (e.g., OVA's) do not conform to the
information presented in Table C-l; another source of response data is needed if such an instrument is
used to monitor VOC levels inside a TTE.
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PAGE C-15
TABLE C-l. CONTRIBUTIONS TO EFFECTIVE CARBON NUMBER3
Atom
C
C
C
C
C
C
o
o
o
o
Cl
Cl
N
Type
Aliphatic
Aromatic
Olefinic
Acetylenic
Carbonyl
Nitrile
Ether
Primary alcohol
Secondary alcohol
Tertiary alcohol, esters
Two or more on single aliphatic C
On olefinic C
In amines
Effective carbon number contribution
1.0
1.0
0.95
1.30
0.0
0.3
-1.0
-0.6
-0.75
-0.25
-0.12 each
+0.05
Similar to 0 in corresponding alcohols
Reference 5.
-------
Toluene:
aromatic -
aliphatic—C 1.0
C.TO
1.0 C /^~\ C 1.0
'C ;'
1.0 C V_X C 1.0
1.0
ECN = 7.0
Perchloroelhylene:
005 Cl Cl 0.05
\095 0 95/
c = c
/ \/ \
0.05 a oteflnlc a 0.05
O
trl
n
I
o\
ECN =
Isopropyl acetate:
aliphatic -
1.0 C ester O aliphatic
I » II 4
1.0 C— O— C— C ECN = 3.75
| -0.25 0.0 1.0
L 1.0 C f
carbonyl
Methyl isobutyl ketone:
aliphatic O C 1 0
I II I
C — C —C 1.0
1.0 0.0 I
t C 1.0
carbonyl |
C 1.0 _
- aliphatic ECN = 5.0
Ethanol:
-0.6
X1.0 C —OH
aliphatic ' | f
1.0 C primary
alcohol
ECN = 1.4
1,1,2 Trichlorocthane:
-0.12
CJ
I 10
i.o c —c—a
l^^
\ aliphatic
Cl
-0.12
ECN =1.76
Figure C 2. Examples of ECN derivations.
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PAGE C-17
{single VOC.. For a single VOC, monitoring considerations are relatively straightforward.
The first step is to determine the relative response of the FIA to the VOC in terms of the FIA
calibration gas (assumed to be propane) using the following equation:
RRVOC * ECNVOC * 3.0 (Equation 5)
where:
RRVOC = the relative response of the FIA to the VOC, ppmv propane per ppmv of the VOC
(ppmv propane/ppmv VOC)
ECNVOC = the effective carbon number of the compound, effective carbon atoms/molecule
VOC
3.0 = the effective carbon number of propane, effective carbon atoms/molecule propane
Note: If a calibration gas other than propane is used, the ECN of the actual calibration gas is used in
Equation 5.
Next, the maximum acceptable monitor reading is calculated by the equation below:
MRmax = RRVOC X Cmax (Equation 6)
where:
MRmax - the maximum monitor reading that is considered acceptable, ppmv propane
RRVOC = the relative response of the FIA to the VOC, ppmv propane/ppmv VOC
Cmax = the maximum acceptable concentration of the VOC, ppmv VOC
As discussed previously, the maximum acceptable VOC concentration in the temporary exhaust
stream is typically considered the PEL, while the maximum for points within the TTE may be
somewhat higher, provided that the exposure of the workers over time does not exceed the PEL and
that no STEL or ceiling level is violated.
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PAGE C-18
EXAMPLE 5.
For the fabric coating operation presented in Example 2, what is the maximum acceptable
monitor reading during CE testing?
Solution. The coating operation uses a single VOC, toluene. As illustrated in Figure C-2, the
ECNfor toluene is 7.0. The relative response for toluene, assuming that the calibration gas for the
test instruments is propane, is found as follows:
RR = 7.0 -i- 3.0
* 2.3 ppmv propane/ppmv toluene
The maximum acceptable toluene concentration in the TTE's temporary exhaust stream is equal to
the PEL, which is 100 ppmv. Using Equation 6, the maximum acceptable monitor reading is
calculated below:
MRmax =2.3 ppmv propane/ppmv toluene x 100 ppmv toluene
= 230 ppmv propane
Thus, an FIA reading of 230 ppmv as propane in the temporary exhaust stream corresponds to a
toluene concentration of 100 ppmv and indicates that the average concentration in the TTE is at the
PEL
An STEL of ISO ppmv also has been established for toluene by OSHA. The STEL is the maximum
15-min, time-weighted average concentration to which workers can be exposed. Thus, points in the
breathing zone of the workers inside the TTE should not exceed this level. The monitor reading
corresponding to the STEL can be calculated using Equation 6:
MRmax = 2.3 ppmv propane/ppmv toluene x 150 ppmv toluene
= 345 ppmv propane
Mixture of VOC's. Where VOC mixtures are used, the process is analogous but more
complicated. As with single-VOC systems, the first step is to calculate the relative response of the
FIA to the VOC mixture in terms of the FIA calibration gas (again assumed to be propane).
However, to calculate this "composite relative response, three substeps are required:
1. First, calculate the relative response for each of the VOC compounds that make up the
mixture using Equation 5 above.
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PAGE C-19
2. Next, calculate the mole fraction of each of the compounds in the gas phase. In the
absence of better data, assume that the mole fractions in the gas phase are equal to the mole fractions
in the liquid phase. This calculation is illustrated in Equation 7 below:
MF. (Vjiq i * PJ) /
rn (Equation 7)
£ KVliq j x
where:
MFj = the mole fraction of VOC i of the mixture, Ib-mole VOCj per Ib-mol of the VOC
mixture (Ib-mol VOCj/lb-mol VOCtot) (The calculation yields the mole fraction in
the liquid phase, which is assumed to be equal to the mole fraction in the gas
phase.)
V|jq i = the volume fraction of VOC i in the liquid phase, gal VOCj/gal VOCtot
Pj = the density of VOC i in the liquid phase, Ib/gal VOCj
MWj = the molecular weight of VOC i, Ib/lb-mol
vliq i = ^e v°lume fraction of VOC j in the liquid phase, gal VOG/gal VOCtol
p: = the density of VOC j in the liquid phase, Ib/gal VOCj
MWj = the molecular weight of VOC j, Ib/lb-mol
m = the number of different VOC's comprising the mixture
Note: The liquid volume fractions (V|jq j and V|jq j) can be expressed relative to the total volatile
portion of the coating, ink. etc. (as expressed above) or to the total volume of the entire coating, ink,
etc. (e.g., gal VOCj/gal coating), provided that all are expressed in consistent terms.
3. Finally, calculate the relative response of the FIA to the VOC mixture using the following
equation:
n
t » £ MFj X RRj (Equation 8)
where:
RRtot = the relative response of the FIA to the VOC mixture, ppmv propane/ppmv VOCtot
MFj = the mole fraction of VOC i of the mixture, expressed as ppmv VOCj/ppmv VOCtot
RRj = the relative response of the FIA to VOC i of the mixture, ppmv propane/ppmv
VOCj
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PAGE C-20
n = the number of different VOC's comprising the mixture
Note: The mole fraction is expressed above in terms of ppmv VOCj/ppmv VOCtot. These units are
equivalent to Ib-mol VOCj/lb-mol VOCtot because, according to the ideal gas laws, the mole fraction
is equal to the gaseous volume fraction and because concentration in ppmv is based on the volume
occupied by the gas.
After the relative response for the VOC mixture has been calculated, the maximum acceptable
monitor reading is calculated by the equation below:
MRmax - RRtot X
cmaxl
x ••• x c
maxn
n (Equation 9)
i x (Cmaxl x Cmax2 x ... x Cmaxn)/Cmaxi]
where:
MR
max
RRtot
..... Cmaxj,..., C
maxj,..., maxn
MFj =
the maximum monitor reading that is considered acceptable,
ppmv propane
the relative response of the FIA to the VOC mixture,
ppmv propane/ppmv VOC^
the maximum acceptable concentration of the indicated VOC
component of the mixture, ppmv VOC
the mole fraction of VOC i of the mixture, expressed as ppmv
VOCj/ppmv VOCtot
the number of different VOC's in the mixture for which a
maximum acceptable concentration is defined
For the temporary exhaust stream, the PEL of the mixture is typically considered the
maximum acceptable concentration. The corresponding monitor reading (in ppmv propane) is
calculated by substituting th.e PEL's of the component VOC's into Equation 9. If PEL's have not
been established for all the components, only those components with a PEL are included in the
Equation 9 calculation. However, the calculation of mole fractions (Equation 7) and relative response
(Equation 8) should include all component VOC's, whether assigned a PEL or not.
Although the PEL of the mixture can be exceeded briefly inside the TTE (provided that the
8-hour, time-weighted average exposure of the workers does not exceed the PEL), any STEL's or
ceilings cannot be exceeded. Equation 9 can be used to calculate the monitor reading that
-------
PAGEC-21
corresponds to the STEL for the mixture by substituting in the STEL's for those components for
which one has been established. Likewise, any ceilings that have been designated can be used to
calculate the monitor reading that corresponds to the mixture ceiling. As discussed above for PEL's,
the mole fractions and relative response used in Equation 9 must be calculated including all
component VOC's, although only the components for which an STEL or ceiling (depending on which
is to be calculated) has been established are included when the maximum monitor reading is
calculated.
Note that it is implicit in Equation 9 that the effects of the component VOC's are additive.
Thus, when the PEL's of the component VOC's are substituted into Equation 9, the resulting MRmax
is the estimated monitor reading when the concentration is at the PEL of the mixture, i.e., when the
concentrations of the components are such that Equation 1 is true. Similarly, when Equation 9 is
used for STEL's or ceilings, the resulting MRmax represents a situation analogous to Equation 1.
This approach is recommended unless there is definitive information that the effects of the
components are not additive.
EXAMPLE 6.
For the multiple-station packaging rotogravure press presented in Example 3, what is the
maximum acceptable monitor reading during CE testing?
Solution. This simplified printing process uses a mixture of toluene, isopropyl acetate, and ethanol.
To calculate the relative response for the mixture, the relative response and mole fraction for each
of the component VOC's must first be determined. Using the ECN's for these compounds derived
in Figure C-2, the relative responses are calculated using Equation 5 for an FIA calibrated with
propane:
Toluene RR = 7.0 + 3.0
*• 2.3 ppmv propane/ppmv toluene
Isopropyl acetate RR = 3.75 + 3.0
* 1.3 ppmv propane/ppmv isopropyl acetate
Ethanol RR " = 1.4-5-3.0
» 0.47 ppmv propane/ppmv ethanol
The mole fraction of each VOC is calculated using Equation 7. The volume fraction
each VOC, which is needed to use Equation 7, is calculated by dividing the volume of the
individual VOC applied per hr (given in Example 3) by the total volume of VOC applied per hr
(23 gal/hr).
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PAGE C-22
(1/23) x 7.21/92.13
Toulene MF » '•
[(1/23) x 7.21/92.13] + [(5/23) x 7.27/102.13] + [(17/23) x 6.57/46.07]
» 0.03 Ib-mol tolueoe/Ib-mol VOCtot
(5/23) x 7.27/102. 13
Isopropyl acetate MF «= - - - ._
[(1/23) x 7.21/92.13] + [(5/23) x 7.27/102.13] -I- [(17/23) x 6.57/46.07]
» 0. 12 Ib-mol isopropyl acetate/lb-mol VOCtot
(17/23) x 6.57/46.07
Ethanol MF « — — — -- - _
[(1/23) x 7.21/92.13] + [(5/23) x 7.27/102.13] + [(17/23) x 6.57/46.07]
* 0.85 Ib-mo! ethanol/lb-mol VOC,ot
When the relative responses and mole fractions have been calculated for each VOC in the mixture,
the relative response for the mixture can be calculated using Equation 8:
RRtot = (0.03 x 2.3) + (0.12 x 1.3) -I- (0.85 x 0.47)
* 0.62 ppmv propane/ppmv VOCtol
The maximum acceptable VOC concentration in the TTE's temporary exhaust stream is the PEL of
the mixture. Using the results of the previous calculations and the PEL'S of the component VOC's,
the maximum acceptable monitor reading for this exhaust stream can be calculated using
Equation 9:
MRmax . 0.62 X X 25° X
max
_
(0.03 x 250 x 1,000) +(0. 12 x 100 x 1 ,000) * (0.85 x 100 x 250)
380 ppmv propane
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PAGE C-23
In addition to PEL's, OSHA has established STEL'sfor toluene (ISOppmv) and isopropyl acetate
(310 ppmv). No STEL has been established for ethanol. To determine the monitor reading when
the STEL for the mixture has been reached, which is the maximum acceptable reading in the
breathing zone of the workers, the individual STEL's are substituted into Equation 9. Only toluene
and isopropyl acetate are included in this calculation:
. 150 x 310
. (0 03 x 310) * (0.12 x 150)
1,056 ppmv propane
Note that the monitor reading at the STEL is nearly three times the PEL value. This fact means
that a worker exposed at the STEL level for some period must spend about twice as long at zero
VOC concentration (or correspondingly longer at some VOC concentration between zero and the
PEL) for the time-weighted average exposure to equal the PEL. Thus, the PEL level should
generally be considered the maximum acceptable monitor reading for the ambient air inside the
TTE, with the understanding that some readings in close proximity to the VOC sources may be
higher.
A simpler approach may be taken for a VOC mixture. The maximum acceptable monitor
reading may be calculated assuming that the entire mixture is composed of the single component with
the most restrictive combination of relative response and acceptable maximum concentration. This
component is the one with the smallest value of MRmax as determined using Equation 6. The highest
acceptable monitor reading is equal to this smallest MRmax value. As shown in the following
example, this approach can be more restrictive than necessary. However, this approach is sure to
avoid exceeding healthful levels and can be used when the relative amounts of component VOC's are
not known.
EXAMPLE 7.
As in Example 4, all the inks used on a multiple-station packaging rotogravure press
contain toluene, isopropyl acetate, and ethanol, but the relative quantities to be used during CE
testing are not known. What is the maximum acceptable monitor reading to ensure that the VOC
concentration does not exceed healthful levels?
Solution. To determine the maximum acceptable monitor reading, the relative response for each
VOC in the mixture is determined using Equation 5, and the value ofMRf^^for each is
calculated using Equation 6. The maximum acceptable monitor reading is the lowest of these
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PAGE C-24
For the TTE's temporary exhaust stream, the MRj^^ values should be based on the PEL's of the
VOC's. Using the relative response values determined in Example 6 and the PEL's, the MR,
values for each VOC are calculated as follows:
'max
Toluene MRmax = 2.3 x 100
= 230 ppmv propane
Isopropyl acetate MRmax = 1.3 x 250
= 325 ppmv propane
Ethanol MRmax = °-47 x l'°°°
= 470 ppmv propane
Based on these calculations, the maximum acceptable monitor reading in the temporary exhaust
stream is 230 ppmv propane, which results from treating the entire VOC mixture as if it wen
toluene. This value is well under the maximum acceptable monitor reading determined in Example
7 using the actual proportion of each VOC in the mixture.
Generally, the level calculated above also should be considered the maximum acceptable monitor
reading in the ambient air of the TTE's work areas. However, the workers may be exposed briefly
to levels up to the STEL. To determine the monitor reading that corresponds to the most restrictive
combination of relative response and STEL, the same procedure is followed using the STEL's in
place of the PEL's. For this example, the MRmaxfor toluene (345 ppmv propane) is lower than
the value for isopropyl acetate (403 ppmv propane) and should be considered the maximum
acceptable monitor reading for any point in the breathing zone of the workers. (No STEL has been
established for ethanol.)
FIRE SAFETY
The approach to fire safety is very similar to that for worker health protection. The greatest
difference is in the higher VOC concentrations that are allowable when workers are not exposed.
Allowable VOC Levels
For fire safety, the Critical parameter is the lower explosive limit (LEL) of a compound or
mixture. The LEL is the lowest concentration of a gas or vapor in air that will sustain combustion.
Above this concentration (up to the upper explosive limit), a transient spark or flame will ignite the
gas or vapor, which will continue to burn until a lack of fuel or oxygen extinguishes it. Below the
LEL, the gas or vapor will not ignite. The LEL is typically expressed in percent by volume.
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PAGE C-25
Lower explosive limits for many compounds can be found in most handbooks on hazardous
materials. For solvents, LEL's typically range from about 1 to 3 percent. Considering that 1 percent
by volume corresponds to 10,000 ppmv, it is clear that health considerations come into play long
before fire safety is of concern.
Sizing the Temporary Exhaust System
The principles of dilution for fire prevention are identical to those for health protection. The
temporary exhaust system must be designed so that the rate at which dilution air enters the enclosure
(which is equal to the temporary exhaust rate) is sufficient to keep the VOC concentration below the
LEL in all parts of the TTE. The Grumpier Chart method or the calculation method can be used to
estimate the temporary exhaust rate necessary for this purpose.
The Crumpler Chan Method
The use of this estimation method for fire safety closely parallels the procedure for worker
health protection. Typically, the VOC concentration (CQ) and volumetric flowrate (QG) of the
captured gas stream are known from test results, and the CE is estimated conservatively. When the
target VOC concentration in the temporary exhaust stream (Cp) has been selected, the Crumpler
Chart or Equation 2b can be used to estimate the necessary temporary exhaust rate (Qp). For
additional information on using the Crumpler Chart, see the section below on worker health
protection.
When workers will not enter the enclosure, the target VOC concentration for the temporary
exhaust stream is based on the LEL. To allow for incomplete mixing, common fire safety practice is
to use 25 percent of the LEL for properly ventilated processes that release VOC's at a uniform rate.
See the section on the calculation method for more information on safety factors.
EXAMPLE 8.
For the industrial fabric coating operation introduced in Example 1, what temporary
exhaust rate should be used for the CE test if no workers will enter the TTE?
Solution. As in Example 1, the values O/CQ (984 ppmv) and QQ (6,159 scfm) are known, and the
CE is conservatively estimated at 80 percent. The VOC used in the process is toluene, which has
an LEL of 1.3 percent, or 13,000 ppmv. Assuming a well ventilated TTE, 25 percent of the LEL
(3,250 ppmv) is the appropriate value for Cpfor this continuous process.
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PAGE C-26
In this case, it is preferable to use Equation 2b rather than the Grumpier Chart. The value
equals 3,250/984, or about 3.3. On the Grumpier Chan, this value is near the extreme
of the plotted 80-percent CE curve, and reading the chart in this range is difficult. To use
Equation 2b, the four known parameter values (CG, QQ, Cp and CE) are substituted in, and the
equation is solved for Qp
6,159 x 1 - °-80 x J*L
' 0.80 3,250
470 scfm
If the process operates at conditions significantly different from standard conditions, the temporary
exhaust rate should be adjusted using Equation 3.
Note that the exhaust rate calculated above for fire safety is only about 3 percent of that determined
in Example 1 for worker health protection.
Use of the Grumpier Chart method to estimate the temporary exhaust rate necessary for fire
safety is subject to the same complications discussed previously in the section on worker health
protection. Consult that section for additional information.
When a VOC mixture is used, common fire safety practice is to base the ventilation rate on
the single most restrictive component of the mixture. If the Crumpler Chan method is to be used in
conjunction with test data in terms of a reference gas (e.g., "as propane"), the most restrictive
component can be determined as discussed in the section on monitoring considerations for worker
health protection. For use with the Crumpler Chart, the reported VOC concentration in the captured
gas stream (CQ) in terms of the reference gas must then be converted, based on the measurement
principle of the test method, to the corresponding value for the most restrictive VOC in the mixture.
If test data are not available and the VOC concentration in the captured gas stream is to be estimated
directly in terms of the most restrictive of the actual VOC's, Expression B can be used to determine
which VOC is the most restrictive (see the section below on the calculation method for fire safety).
The Calculation Method
The first step in using the calculation method to determine the temporary exhaust rate
necessary for fire safety is to estimate the fugitive emission rate that will prevail during the CE test.
When this parameter has been estimated, the necessary fugitive exhaust rate can be calculated as
discussed below.
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PAGE C-27
Single VOC. The temporary exhaust rate for a single VOC system can be calculated using
Equation 10, which is very similar to Equation 4. As previously discussed, standard conditions are
those defined for EPA testing, i.e., 68°F and 29.92 in. Hg. If the actual temperature or pressure
differ significantly from these standard conditions, the temporary exhaust rate should be adjusted
using Equation 3.
385 X p X ER X Sf
rt - (Equation 10)
LEL X 10~2 x MW X B
where:
Q = the temporary exhaust rate, scfrn
385 = the volume occupied by 1 Ib-mol of an ideal gas at standard conditions, std. ft-*
VOC/lb-mol
p = the density of the liquid VOC, Ib/gal
ER = the fugitive emission rate in terms of the amount of liquid VOC evaporating, gal/min
Sf = a safety factor to allow for incomplete mixing, dimensionless
LEL = the LEL for the gaseous VOC, percent
10~2 = a factor to adjust for the fact that the LEL is in terms of percent by volume, which is
actually "std. ft3 VOC/102 std. ft3 total gas" (i.e., air plus VOC)
MW = the molecular weight of the VOC, Ib/lb-mol
B = a factor to take into account the fact that the LEL decreases at elevated temperature,
dimensionless
(When the fugitive emission rate [ER] is more readily estimated as a mass emission rate, the value in
Ib/min can be used in Equation 10, and the density of the VOC [p] can be omitted.)
The safety factor, Sf, is determined by the percent of the LEL that is considered safe. In
most cases, it is desirable the keep the concentration at or below 25 percent of the LEL at all points.
(In the absence of sophisticated controls, 25 percent of the LEL is typically the maximum allowed by
fire insurance carriers.) Thus, for a continuous process and a properly ventilated TTE, the value of
Sf is 4, corresponding to 25 percent of the LEL. For a batch process in a properly ventilated TTE,
the existence of a peak emission rate requires a Sf value of 10 or 12. For poorly ventilated TTE's, a
higher Sf value may be required.9
The factor B is included because the LEL decreases at high temperatures. Up to 250eF, a
value of 1 should be used; above 250°F the value should be O.7.9
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PAGE C-28
Note that for these calculations, the background concentration of the VOC is not accounted
for as it was in Equation 4 for health ventilation. Because background levels are typically well under
100 ppmv, this factor is negligible at LEL concentrations. However, in any case where background
level is significant, it should be considered.
EXAMPLE 9.
For the fabric coating operation first introduced in Example 2, what temporary exhaust rate
should be used for the CE test if no workers will enter the TTE?
Solution. The fugitive emission rate for this single-VOC process was estimated in Example 2 at
0.017 gal/min of toluene. The LEL for toluene is 1.3 percent, the density is 7.21 Ib/gal, and the
molecular weight is 92.13 Ib/lb-mol. For this continuous process, assuming a properly ventilated
TTE, the appropriate value for Stis 4. The TTE operates at the faculty's ambient temperature, so
the appropriate value for B is 1. Using these parameter values, the temporary exhaust rate
necessary for fire prevention is calculated using Equation 10:
_ 385 x 7.21 x 0.017 x 4
1.3 x 10'2 x 92.13 x 1
O = 160 scfin
If the actual temperature or pressure are significantly different from standard conditions, the
temporary exhaust rate should be adjusted to reflect the difference using Equation 3.
Note that the exhaust rate required for fire safety is less than one percent of that calculated in
Example 2 for worker health protection.
Mixture of VOC's. In fire safety calculations, it is common practice to assume that the
entire mixture is composed of the single component that requires the greatest quantity of dilution air
per unit liquid volume. This component is the one with the largest value for the following
expression:
(Expression B)
LEL x MW
where the symbols have the meanings defined for Equation 10. (When the fugitive emission rate
[ER] has been estimated in terms of Ib/min, the density of the of the VOC [p] can be omitted from
Expression B to determine which component requires the greatest quantity of dilution air per unit
mass.) This approach may result in a greater temporary exhaust rate than is absolutely necessary, hut
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PAGE C-29
at the dilution volumes necessary for fire prevention, this consideration is not typically a major
concern.
EXAMPLE 10.
For the multiple-station packaging rotogravure press first introduced in Example 3, what
temporary exhaust rate should be used for the CE test if no workers will enter the TIE?
Solution. To determine which VOC to base the temporary exhaust rate on, calculate the value of
Expression B (presented above) for each of the known constituents. The LELfor toluene is
1.3 percent, the LEL ofisopropyl acetate is 1.8 percent, and the LEL ofethanol is 3.3 percent.
Densities and molecular weights are given in Example 3.
7.21
Toluene »0.06
1.3 x 92.13
7.27
Isopropyl acetate <*0.04
1.8 x 102.13
6.57
Ethanol »0.04
3.3 x 46.07
Because the value for toluene is the largest, the temporary exhaust rate is calculated assuming that
the entire VOC mixture is composed of toluene. Assuming that approximately 20 percent of the
total 23 gal/hr of VOC's escapes as fugitive emissions (based on an earlier liquid/gas material
balance CE test as presented in Example 3), the fugitive emission rate is about 4.6 gal/hr. Using
Equation 10 (with a factor of 60 in the denominator to convert the emission rate to gal/min), the
temporary exhaust rate is calculated as follows:
« 385 x 7.21 x 4.6 x 4
1.3 x 10"2 x 92.13 x 1 x 60
710 scfm
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PAGE C-30
If actual conditions are significantly different from standard conditions, the temporary exhaust rate
should be adjusted using Equation 3.
The exhaust rate calculated for fire safety in the example above is only about II percent of the
exhaust rate calculated for health protection in Example 3 (based on the individual emission rates
of the component VOC's) and only about 2 percent of the health protection exhaust rate calculated
in Example 4 (based on the worst-case VOQ.
Monitoring Considerations for Fire Safety
As is the case when health protection is the concern, it is advisable to monitor the VOC
concentration in the TTE during CE testing to ensure that fire safety is maintained. The principles
and calculations for fire safety monitoring are the same as previously discussed for health protection.
The instrument measuring VOC concentration in the temporary exhaust stream during the CE
test serves as a continuous monitor of the average concentration in the nt. At no time should the
concentration in this exhaust stream exceed 25 percent of the LEL. If the TTE is not well ventilated
to achieve good mixing, it is advisable to set a lower maximum acceptable concentration for the
temporary exhaust stream.
In addition, various points within the TTE should be periodically monitored after the TTE has
been erected. Here again, the maximum acceptable VOC concentration at any location away from the
fugitive emission points themselves is 25 percent of the LEL.
The monitor reading that corresponds to the selected maximum acceptable VOC concentration
can be determined using the information and equations presented previously in the section on
monitoring considerations for health protection. To use the equations in that section as written, it is
necessary to express the LEL in ppmv rather than in percent by volume. For this conversion, each
1 percent by volume is equal to 10,000 ppmv.
EXAMPLE 11.
For the multiple-station packaging rotogravure press first introduced in Example 3, what is
the maximum acceptable monitor reading during CE testing if no workers will enter the TTE?
What is the maximum acceptable monitor reading if the relative quantities of the VOC's are not
known, as in Example 4?-
Solution. The solution to the first part of this example parallels Example 6. The relative response
and mole fraction for each of the VOC's that make up the mixture are determined using
Equations 5 and 7, respectively, and these parameters are used to calculate the relative response for
the mixture using Equation 8. The maximum allowable VOC concentration for the TTE is
25 percent of the LEL. The corresponding maximum acceptable monitor reading is calculated
using Equation 9. For use in Equation 9, the LEVs for the component VOC's (listed above in
Example 10) must be converted to ppmv by multiplying each by 10,000, and each must be
-------
PAGE C-31
multiplied by 0.25 to correct to 25 percent of the LEL. The resulting values of Cmaxfor toluene,
isopropyl acetate, and ethanol art 3,250 ppmv, 4,500 ppmv, and 8,250 ppmv, respectively. Using
these values and the mole fractions and relative response for the mixture determined in Example 6,
the calculation is as follows:
MR ,062x 3,250X4,500X8,250
max (0.03 x 4,500 x 8,250)+(0.12x3,250x8,250)+(0.85x3,250x4,500)
* 4,500 ppmv propane
(Alternatively, the LEL in terms of percent by volume can be used in Equation 9, and the result
multiplied by 2,500 to correct for both ppmv and the limitation to 25 percent of the LEL.)
For the case where the components of the mixture are known, but the mole fractions cannot be
calculated, the determination of the maximum acceptable monitor reading parallels the process
illustrated in Example 7. The relative response for each VOC in the mixture is determined using
Equation 5. This value and the Cwflr value for each VOC (computed from the LEL as discussed
above) are used in Equation 6 to determine the MRmaxfor each VOC. The maximum acceptable
monitor reading is the lowest of these MRmax values. For the example rotogravure press that uses
toluene, isopropyl acetate, and ethanol, the Equation 6 calculations are illustrated below:
Toluene MRmax = 2.3 x 3,250
» 7,500 ppmv propane
Isopropyl acetate MRmax = 1.3 x 4,500
• 5,800 ppmv propane
Ethanol MRmax = 0.47 x 8,250
- 3,900 ppmv propane
Based on these calculations, the maximum acceptable monitor reading for the TTE is
3,900 ppmv propane, which results from treating the entire VOC mixture as ethanol. This value is
not much lower than the value determined above using the individual VOC's because ethanol is
both the most restrictive component (lowest MR^^) and the most plentiful.
REFERENCES FOR APPENDIX C
1. Occupational Safety and Health Administration. Air Contaminants-Permissible Exposure
Limits. Title 29, Code of Federal Regulations, Pan 1910.1000. 1989.
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PAGE C-32
2. Industrial Ventilation, 20th Ed. Lansing, Michigan, American Conference of Governmental
Industrial Hygienists, Inc. 1988. p. 2-6.
3. Reference 2, p. 5-23.
4. Reference 2, pp. 2-4 and 2-5.
5. Modern Practice of Gas Chromatography, 2nd Ed.; Robert L. Grob, ed. New York,
John Wiley & Sons, p. 248.
6. Dietz, W.A. Response Factors for Gas Chromatographic Analyses. Journal of Gas
Chromatography. February 1967.
7. Ackman, R.G. Fundamental Groups in the Response of Flame lonization Detectors to
Oxygenated Aliphatic Hydrocarbons. Journal of Gas Chromatography. £: 173-179. June 1964.
8 Ettre, L.S. Relative Response of the Flame lonization Detector. Journal of Chromatography.
3:525-530. August 1962.
9. Reference 2, p. 2-7.
-------
APPENDIX D
TEMPORARY TOTAL ENCLOSURE DESIGN CASE STUDY
-------
PAGE D-l
TEMPORARY TOTAL ENCLOSURE DESIGN CASE STUDY
A packaging manufacturing company is required to determine the capture efficiency (CE)
achieved by one of its multiple-color, web-fed rotogravure presses. From the unwind equipment
through the cutting and stacking equipment, the press is about 120 feet (ft) long. The printing
stations of the press, where the inks are applied and dried and the volatile organic compounds
(VOC's) are emitted, constitute about 60 ft of the press. The maximum web width that the press can
accommodate is 4 ft. The overall width of the press is about 8 ft.
Based on a survey of the facility, the most practical temporary total enclosure (TTE)
configuration consists of walls paralleling the length of the press, front and back, with end walls
crossing the path of the web to enclose the print stations. The easiest place to cross the line upstream
of the print stations is between the unwind equipment and the web splicer, about 20 ft from the first
print station. Downstream from the print stations, the best place to erect the end wall is between the
final print station and the cutting equipment, about 10 ft from the final print station. To allow
adequate room for working both inside and outside the TTE, the wall along the front of the press is
best placed midway across the aisle between the test press and the back of the adjacent press, about
10 ft from the front of the print stations. The wall along the back of the press, where very limited
access is required, can be erected most easily about 8 ft from the back of the print stations. It is
easier and less disruptive to the operation of the press during construction to extend the TTE walls all
the way up to the plant ceiling than to construct a TTE roof spanning the press. The most practical,
least disruptive location for the temporary exhaust system is at the unwind end of the press at floor
level, with the pickup extending through the end wall of the TTE on the back side of the press. A
schematic of the proposed Tit configjration is presented in Figure D-l. In the paragraphs below,
the steps for TTE evaluation and design presented in Chapter 5 are applied to this example case.
Step 1. Evaluate the essential natural draft openings (NDO'st and exhaust points against
the TTE criteria.
Criterion 1: The separation between NDO's and VOC sources must be at least four times the
equivalent diameter (ED) of the NDO.
-------
Proposed
TIE
Temporary
Exhaust
System
2(
ft
DOWNSTREAM j BACK WALL
END WALL 8 ft
1 i
t
j
Web
Guide
10ft
| FRONT WALL
f
Web
:estoon Splicer
— ,. ... . OA ft m
* yu n w
' (*J
Unwind
UPSTREAM
END WALL
o
m
o
f'o
MCOOC * «*• Km; 06ta»l
Figure D-J
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PAGE D-3
Essential NDO's and associated ED's:
• Web entrance slot - 6 ft wide by 3 ft high
(This height needed to allow worker access to the web splicer.)
ED - (4 *TtV**) = 4.8 ft; 4 x ED = 19.2 ft
• Web exit slot — 6 ft wide by 5 inches (in.) high
(No worker access needed at exit.)
ED = 1.8 ft; 4 x ED = 7.2ft
Separation of NDO's and nearest VOC sources:
• Web entrance slot to first print station - 20 ft
20 ft > 4 x ED
• Web exit slot to final print station - 10 ft
10 ft > 4 x ED
Criterion 1 is satisfied.
Criterion 2: The separation between exhaust points and NDO's must be at least four times the ED of
the exhaust opening.
Exhaust points and associated ED's:
• Print station dryers' entrance and exit slots — 5 ft by 4 in.
(Each print station has a dryer mounted above the print cylinder.)
ED = 1.5 ft; 4 x ED = 6ft
• Temporary exhaust system pickup - 3 ft x 3 ft
(Dimensions approximate; actual duct size determined later when flow rate estimated.)
ED = 3.4 ft; 4 x ED = 13.6 ft
Separation of exhaust points and nearest NDO's:
• Dryer slots'to TTE web slots - closest is final print station dryer to web exit slot,
about 10 ft
10 ft > 4 x ED
• Temporary exhaust pickup to web entrance slot - about 5 ft
5 ft < 4 x ED
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PAGE D-4 _ _
• Add a baffle joining the TTE end wall to the web splicer housing between the
temporary exhaust pickup- and the web entrance slot -- airflow path between the
exhaust and the NDO is increased to over 4 x ED
Criterion 2 is satisfied.
Criterion 3: The total area of the NDO's must be no more than 5 percent of the total area of the
TTE's wall, ceiling, and floor.
Area of NDO's:
• Web entrance slot - 18 square feet (ft )
• Web exit slot - 2.5 ft2
• Total - 20.5 ft2
Area of TTE:
• Dimensions - 90 ft long by 26 ft wide by 26 ft high
• Front and back walls - 90 ft by 26 ft each
• End walls - 26 ft by 26 ft each
• Ceiling and floor - 90 ft by 26 ft each
• Total area - 10,712 ft2
Ratio of areas - less than 0.2 percent
Criterion 3 is satisfied.
Criteria 4 and 5: Not evaluated at this stage.
Step 2. Determine the volume of the permanent exhausts and forced makeup air in
TTE.
Exhausts: The only permanent exhausts are those from the dryers on the print stations. These
exhausts are joined into a common duct to the control device. The dryers have dampers that
are positioned automatically based on the VOC concentration, so the total exhaust from the
press can vary from about 3,000 actual cubic feet per minute (acfrn) to 12,000 acfrn
depending on the quantity of VOC being applied in the inks. The press exhaust temperature
is typically about 110°F.
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PAGE D-5
Makeup air: One of several forced makeup air units at the facility is within the proposed TTE.
However, the unit is not configured to allow volumetric flow measurements using EPA
methods. Therefore, the unit will not be operated during the test, and its openings will be
sealed to prevent air from passing in or out. The effective forced makeup air volume during
testing is zero.
Step 3. Estimate the temporary exhaust rate needed to maintain a safe and healthful
atmosphere inside the TTE. As discussed in detail in Appendix C, there are two methods for
estimating the necessary temporary exhaust rate: the Crumper Chart method and the calculation
method. Both methods are illustrated below.
Quantity of VOC's: The facility indicates that a maximum of 150 to 200 pounds per hour
(Ib/hr) of VOC's are contained in the inks applied on the press. The CE is estimated to be in
the range of 80 percent. Thus, a maximum of about 160 Ib/hr of VOC's are captured and
vented to the control device, and the greatest fugitive VOC generation rate is about 40 Ib/hr.
Identity of VOC's: The many inks used by the facility contain a wide range of VOC
formulations. Alcohols and acetates generally predominate, but a significant quantity of
toluene also is used. The exact proportions that will prevail at the time of the test are
unknown. To be on the safe side, the mixture is considered to be 100 percent toluene for the
exhaust estimations. This approach results in a more restrictive (higher) exhaust rate. (See
Appendix C for background information.)
Appropriate safety factor: Workers will enter the TTE from time to time during testing, so worker
exposure considerations, rather than fire safety, take precedence. As discussed in
Appendix C, the calculation method for estimating the necessary temporary exhaust rate uses
a safety factor (K) to account for incomplete mixing within the TTE. However, because a
"safety factor" has already been introduced in this case by treating the entire VOC mixture as
toluene, a K value of 1 can be used in the temporary exhaust rate calculation.
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PAGE D-6 . __
Background VOC concentration: Measurements made by the facility indicate a background VOC
concentration of 20 parts per million by volume (ppmv). Information on the identity of the
reference compound and the measurement method is unavailable. For the calculation method
of estimating the necessary temporary exhaust rate, the background concentration is assumed
to be 20 ppmv toluene.
Exhaust rate estimation:
Grumpier Chart Method. This method is best suited for use when test results from the
process being evaluated are available. However, even in the absence of test data, the method
can be used if the VOC concentration and volumetric flowrate of the captured gas stream can
be estimated. For this process, the volumetric flowrate of the captured gas stream is known,
and the VOC concentration can be estimated based on this flowrate and the VOC mass
emission rate in the captured gas stream, which also is known.
As indicated above in Step 2, the volumetric flowrate of the captured gas stream varies from
about 3,000 acfm to 12,000 acfm at 110°F. Assuming that the process operates at near
standard pressure (29.92 in. of mercury [in. Hg]), this range equals approximately 2,800
standard cubic feet per minute (scfm) to 11,100 scfm (see Appendix C, Equation 3). For this
example, a value of 10,000 scfm is selected. (Any value in the range could be selected
without affecting the outcome because, given a fixed VOC mass flowrate, the volumetric
flowrate and VOC concentration of the captured gas stream are inversely proportional.)
Given that the volume occupied by 1 pound-mole (Ib-mol) of an ideal gas at standard
conditions (68°F and 29.92 in. Hg) is 385 standard cubic feet (std. ft3) and that the molecular
weight of toluene is 92.13 Ib/lb-mol, the VOC concentration is calculated as follows for the
selected volumetric flowrate:
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PAGE D-7
160 lb toluene x 385 std. ft3 toluene x 1Q6
Ib-mol toluene _ . i.iQOppmv
x 92.13 lbtoluene x 10,000 scftn total exhaust
hr Ib-mol toluene
(The factor 10° that appears in the numerator is necessary to convert the expression into
terms of ppmv.)
Based on the results of the calculation above, the VOC concentration in the captured gas
stream (CQ) (assuming 100 percent toluene) is about 1,100 ppmv at a volumetric flowrate
(QQ) of 10,000 scfm. The Permissible Exposure Limit (PEL) for toluene is 100 ppmv; this
value is used as the target value for the VOC concentration in the temporary exhaust stream
(Cp). As indicated previously, the CE is estimated at 80 percent. With these four values, the
Grumpier Chart can be used to estimate the appropriate temporary exhaust rate (Qp). The
use of the Grumpier Chan is illustrated in Figure D-2 and explained below.
The value of Cp/CG is 100/1,100, or about 0.09. This point on the y-axis of Figure D-2 is
represented by Point A. From Point A, a line parallel to the x-axis is drawn to the curve
representing the estimated CE; the point of intersection is represented by Point B in
Figure D-2. From Point B, a line parallel to the y-axis is drawn downward to the x-axis.
The intersection is at Point C in Figure D-2; the value at this point is about 2.75. Thus,
is equal to 2.75, and Qp equals 27,500 scfm.
Calculation Method. By this method, the temporary exhaust rate necessary to maintain
healthful conditions is estimated using Equation 4 from Appendix C. Because the emission
rate (ER) is already known in terms of mass, this value (40 Ib/hr) can be used directly in the
equation without being multiplied by the density (p), as is necessary when the emission rate is
in terms of liquid volume. Also, a factor of 60 is included in the denominator of the equation
to convert the emission rate from Ib/hr to Ib/minute. The molecular weight of toluene is
92.13 Ib/pound-mole, and the PEL is 100 ppmv. Using the parameter values given above,
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PAGE D-8
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PAGE D-9
the necessary temporary exhaust rate is estimated as follows:
Q . 385' x 40 x 1
(100 - 20) x 10"6 x 92.13 x 60
35,000 scfm
The difference between this estimate and that derived using the Grumpier Chart method
results from the inclusion of the background VOC concentration in this calculation. In this
case, the assumption that all the VOC is toluene is so conservative that the temporary exhaust
rate estimated using the Grumpier Chart is very likely to be sufficient to maintain a healthful
atmosphere inside the TTE. This example emphasizes, however, how important it is to use
conservative assumptions and estimates when estimating the necessary temporary exhaust rate
using the Grumpier Chart method.
Adjustments for Temperature and Pressure. Regardless of which estimation method is used,
the estimated temporary exhaust rate may have to be adjusted for temperature and pressure.
See Appendix C for information on flowrate adjustments to compensate for differences
between actual and standard conditions.
For the process in this case study, which operates at ambient temperature, the volume
determined above at standard temperature (68°F) can be used without adjusting for
temperature. Also, it is assumed that the facility is located at an elevation of less than
1,000 ft above sea level and operates at ambient atmospheric pressure, so no adjustment for
pressure is necessary. Thus, the actual temporary exhaust rate needed is a maximum of
35,000 acftn.
Because of the conservative assumptions used in calculating this value (e.g., largest possible
fugitive emission rate, 100 percent toluene), this is the maximum exhaust rate that should ever
be needed. Field conditions may not warrant such a high exhaust rate, so a system with
variable flowrate is advisable.
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PAGE D-10
Note that with the temporary exhaust rate estimated at a maximum of 35,000 acfm, the
system pickup and duct dimensions assumed for Step 1 (3 ft by 3 ft) are acceptable. With this
size duct and this exhaust rate, the flow rate in the duct is somewhat less than 4,000 feet per
minute (ft/min), which is certainly acceptable for a temporary test system such as this.
Step 4. Determine the net total exhaust rate, calculate the average face velocity (FV)
across the essential NDO's. and compare this FV to the required value.
Net total exhaust rate: The CE test procedures require FV calculations to be carried out in terms of
scfm (see Appendix B, Method 204). From Step 2 above, the dryer exhaust totals 3,000 to
12,000 acftn at 110°F, which is equivalent to about 2,800 to 11,100 scfm (see Appendix C,
Equation 3). The forced makeup air is zero. From Step 3, the estimated maximum
temporary exhaust volume is 35,000 scfm. However, this temporary exhaust volume was
determined using a series of conservative assumptions, so it is likely that under test conditions
the actual exhaust rate will not be so high. Because the average FV ultimately must be
determined under field conditions, it is important not to overestimate the temporary exhaust
rate during this step. For a conservative evaluation in this step, a value of one-half the
calculated value is used, and the minimum permanent exhaust value is used. (These values
were selected based on the information presented in this case study. In other situations, other
values would be appropriate. For example, if the temporary exhaust rate were estimated
based on a known VOC mixture, the total calculated exhaust rate might be used.) The net
total exhaust rate is calculated below:
net total m permanent _ e + temporary
" ~
_
exhaust exhaust ~ exhaust
= 2,800 scfm - 0 * 17,500 scfm
= 20,300 scfm
Average FV across the essential process NDO's: In Step 1, it was determined that the total area of
the web entrance and exit slots is 20.5 ft . If these *
velocity across them would be calculated as follows:
the web entrance and exit slots is 20.5 ft. If these were the only NDO's, the average face
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PAGED-11
net exhaust
total NDO area
20,300 scfm
20.5 ft2
990 ft/min
Criterion 4: The average FV across all NDO's must not be less than 200 ft/min.
Criterion 4 is satisfied.
StepS. Select a target FV and determine the maximum NDQ area that will meet the
criteria.
Target FV: A value of 250 ft/min gives some room for error but is not excessive.
Maximum NDO area that meets Criterion 4:
NDO _ net total exhaust
area " target FV
= 20,300 scfm
250 ft/min
- 81 ft2
Maximum NDO area that meets Criterion 3: The total area of the NDO's cannot exceed
5 percent of the surface area of the TTE structure. Using the TTE area determined in Step 1,
the maximum NDO area is calculated below:
NDO - 0.05 x
area area
0.05 x 10,712 ft2
536ft2
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PAGE D-12
Step 6. Evaluate possible locations and sizes of supplemental NDO's to improve
ventilation of the TTE.
Allowable area of supplemental NDO's: As indicated in Step 5, Criterion 4 is far more restrictive
than Criterion 3. Thus, the total NDO area should not exceed the 81 ft dictated by
Criterion 4. Given that the NDO's essential to the process (the web entrance and exit slots)
1 1
total 20.5 ft, supplemental NDO's up to a total of 60.5 ft may be added.
Although supplemental NDO's are not necessary to meet the TTE criteria, it is advisable to
add as much supplemental NDO area as possible. The supplemental NDO's not only improve
the ventilation of the TTE, but they reduce the pressure differential between the outside of the
TTE and the inside, thereby reducing the stress on the TTE structure.
Arrangement of supplemental NDO's: The supplemental NDO's are located so as to improve the
ventilation of the TTE. This aim is accomplished by providing for good mixing of the air in
the TTE to prevent high VOC concentrations from building up in stagnant areas and by
generally sweeping the VOC's from the breathing zone of the workers. To accomplish good
mixing, numerous NDO's are provided at all levels and on all sides of the TTE. In this case.
to sweep the breathing zone, the predominant flow of air should be along the length of the
TTE toward the upstream wail where the temporary exhaust system pickup is located and
from the front side of the press (where personnel sometimes work) toward the back side
(where access is seldom needed). To produce this airflow pattern, relatively larger/more
numerous NDO's are provided at the opposite end of the TTE from the temporary exhaust
system pickup and in the TTE wall paralleling the front side of the press. One possible
configuration of NDO's is presented in Figure D-3.
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PAGED-13
26ft
B
90ft
FRONT WALL
Supplemental NDO Area 25 ft2
Temporary
Exhaust
BACK WALL
Supplemental NDO Area 12.5 ft2
Web Exit
Slot, 2.5 ft2
Temporary _
Exhaust Pickup at - *~ ]
Upstream End Wall
26 ft
26ft
DOWNSTREAM END WALL
Supplemental NDO Area 16 ft2
26ft
[2 E3
26 ft
Web Entrance
Slot. 18ft2
Temporary
Exhaust Pickup
3ftx3ft
UPSTREAM END WALL
Supplemental NDO Area 7 ft2
Figure D-3
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GLOSSARY OF TERMS
Affected facility means any process, line, or operation that is subject to a regulation or
standard.
Captured emissions (G) means all emissions that are delivered to a control device.
Capture device means a hood, enclosure, room, floor sweep, or other means of containing or
collecting VOC's and directing those VOC's into a duct.
Capture efficiency means the fraction of all VOC generated by and released at an affected
facility that is directed to a control device.
Control device means any equipment that reduces the quantity of VOC that is emitted to the
atmosphere. The device may destroy the VOC or secure it for subsequent recovery or
disposal. Examples of control devices are incinerators, carbon adsorbers, and condensers.
Control device efficiency means the ratio of the VOC destroyed or recovered by a control
device to the VOC delivered to the control device, usually expressed as a percentage.
Control system means any combination of capture and control devices.
Control system efficiency means the fraction of gaseous VOC that is generated at an affected
facility that is prevented from entering the atmosphere as a result of the performance of its
capture and control devices. Mathematically, it is the product of the efficiencies of the
capture and control devices.
Equivalent diameter means the square root of the quantity four times the area of an opening
divided by pi, i.e., [(4 x area)/ir)"A
Exhaust rate means the volumetric flow rate of gas that is withdrawn from a given space.
Forced makeup air means air blown into an enclosure or oven by one or more fans to
replace air that has been exhausted.
Fugitive emissions (F) are traditionally defined as emissions that do not pass through a stack
or duct that allows for their measurement. However, within the context of this document,
fugitive emissions means all emissions that escape to the atmosphere without passing through
a control device, regardless of how they are emitted.
Natural draft opening (NDO) means any permanent opening in a room, building, or total
enclosure that remains open during operation of the facility and is not connected to a duct in
which a fan is installed. The "natural draft" rate and direction across the opening is a
consequence of the difference in pressures on either side of the wall containing the opening.
Overall control efficrency means the fraction of all the VOC's generated by an affected
facility that is prevented from entering the atmosphere as a result of the performance of the
control system that serves the affected facility. The overall control efficiency may be less
than the control system efficiency because of additional VOC emissions downstream of the
affected facility, such as evaporation of VOC from spray booth wastewater or of solvent
retained in the product.
Permanent total enclosure means a permanently installed total enclosure from which all
exhaust streams are discharged to a control device.
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GLOSSARY OF TERMS
Temporary total enclosure means a total enclosure that is constructed for the sole purpose of
measuring fugitive emissions from an affected facility.
Total enclosure means a structure that completely surrounds a source of emissions so that all
VOC emissions are contained for discharge. With a total enclosure, there will be no fugitive
emissions, only stack emissions. The only openings in a total enclosure are forced makeup
air and exhaust ducts and any NDO's, such as those that allow raw materials to enter and
exit the enclosure for processing. All access doors or windows are closed during routine
operation of the enclosed source.
Volatile organic compound (VOC) means any organic compound that participates in
atmosphere photochemical reactions. This includes any organic compound other than the
following compounds: methane, ethane, methyl chloroform (1,1,1-trichloroethane),
CFC-113 (l,l,2-trichloro-l,2,2-trifluorethane), methylene chloride, CFC-11
(trichlorofluoromethane), CFC-12 (dichlorodifluoromethane), CFC-22
(chlorodifluoromethane), FC-23 (trifluoromethane), CFC-114 (1,2-dichloro-l, 1,2,2-
tetrafluoroethane), CFC-115 (chloropentafluoroethane), HCFC-123 (l.l-dichloro-2,2,2-
trifluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HCFC-141b (1,1-dichloro-l-
fluoroethane), and HCFC-l42b (l-chloro-l,l-difluoroethane). These compounds have been
determined to have negligible photochemical reactivity. For purposes of determining
compliance with emission limits, VOC will be measured by the approved test methods.
Where such a method also inadvertently measures compounds with negligible photochemical
reactivity, an owner or operator may exclude these negligibly reactive compounds when
determining compliance with an emissions standard. (The following compounds and classes
of compounds have been proposed in the Federal Register [56 FR 11387, March 18, 1991]
for addition to the list of negligibly photochemically reactive compounds: HCFC-124 (2-
chloro-1,1,1,2-tetrafluoroethane; HFC-125 (pentafluoroethane); HFC-134 (1,1,2,2-
tetrafluoroethane); HFC-143a (1,1,1-trifluoroethane); HFC-152a (1,1-difluoroethane); cyclic.
branched, or linear, completely fluorinated alkanes; cyclic, branched, or linear, completely
fluorinated ethers with no unsaturations; cyclic, branched, or linear, completely fluorinated
tertiary amines with no unsaturations; and sulfur-containing perfluorocarbons with no
unsaturations and with sulfur bonds only to carbon and fluorine.)
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TECHNICAL REPORT DATA
'Please read Instructions on the reverse
REPORT NO.
EPA- 450/4-91-020
2.
3. RECIPIENT'S ACCESSION NO.
TITLE AND SUBTITLE
The Measurement Solution
Usinq a Temporary Total Enclosure for Capture
;5. REPORT DATE
! August 1991
6. PERFORMING ORGANIZATION CODE
3ing a Temporary 1
uficiency Testing
AUTHOR(S)
Stephen,;;. Edgerton
Joanne Kempejrr
Thomas W. T.ar
i. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
401 Harrison Oaks Boulevard, Suite 350
Gary, North Carolina 27513
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-DO-0137
2. SPONSORING AGENCY NAME AND ADDRESS
EiivLssion Standards Division
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, lie 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final Enabling Docuraant
114. SPONSORING AGENCY CODE
5. SUPPLEMENTARY NOTES
EPA Work Assignment Manager-
Karen Catlett, ESD/CPB/CAS, Research Triangle Park,
6. ABSTRACT
This document presents guidance for determining VDC capture
efficiency with the gas/gas protocal using a temporary total enclosure.
Permanent total enclosure criteria also are presented. Appendices
present sample calculations, the test methods, information on health
and safety considerations, and an example case study.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Held/Group
Air Pollution
volatile Organic Compounds
Performance Testing
Capture Efficiency
Temporary Total Enclosure
Determination of VOC
Capture Efficiency
IB. DISTRIBUTION STATEMENT
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Release Unlimited
Unclassified
121. NO. OF PAGES
i 153
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I Unclassified
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