REFERENCE METHOD
European Council of Vinyl Manufacturers
Identification, measurement and control of fugitive emissions
from process equipment leaks
October 2004, rev. 2
O/Ref.: 603684
Member of the SNC-Lavalin Group
TABLE OF CONTENTS
1.
DEFINITIONS ............................................................................................................................................. 1
2.
OBJECTIVES ............................................................................................................................................. 3
3.
SCOPE OF APPLICATION ........................................................................................................................ 3
4.
ECVM PERFORMANCE GUIDELINES APPLICABLE FOR VCM AND EDC........................................... 4
4.1
4.2
4.3
4.4
4.5
5.
METHOD OF ASSESSMENT..................................................................................................................... 5
5.1
5.2
5.3
5.4
5.5
6.
Leak Level Definition .......................................................................................................................... 4
Leak Rate ........................................................................................................................................... 4
Measurement Frequency ................................................................................................................... 4
Repair and Maintenance .................................................................................................................... 4
Non-Accessible Equipment ................................................................................................................ 5
Principle of the Method ...................................................................................................................... 5
Inventory of Sources .......................................................................................................................... 5
Targeted Equipment........................................................................................................................... 6
Database ............................................................................................................................................ 7
Screening Measurements of Process Equipment .............................................................................. 8
TYPICAL REPORTS GENERATED ......................................................................................................... 11
6.1 Leaking Equipment Report............................................................................................................... 11
6.2 Emission Report ............................................................................................................................... 11
7.
REFERENCE DOCUMENTS.................................................................................................................... 11
8.
RESOURCES PERSONS ......................................................................................................................... 12
FIGURES
Figure 5-1 :
Figure 5-2 :
Figure 5-3 :
Figure 5-3 :
P&IDs Review and Points Numbering ......................................................................................... 6
Database Elaboration (example using DÉFI Software)................................................................ 8
Measurement of VOC Emissions ............................................................................................... 9
Application of Response Factor and Correlation Equation ...................................................... 10
APPENDICES
Appendix A:
Appendix B:
Appendix C:
Appendix D:
Appendix E:
Example of a leak report
Example of emission reports
Implementing a leak detection and repair program
Final ECVM correlation curves
Response factors and speciation
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1. DEFINITIONS
Actual concentration
True concentration of the chemical compound or mix of
chemical compounds around a monitored process
equipment
Calibration gas
The VOC substance used to adjust the instrument meter
reading to a known value. The calibration gas is usually
the reference compound at predefined concentration
ECVM
European Council of Vinyl Manufacturers
EDC
Ethylene dichloride (12-dichloroethane)
Fugitive emissions
Emissions of volatile organic compounds into the
environment resulting from a gradual loss of tightness from
process equipment designed to contain an enclosed fluid
(gaseous or liquid), basically caused by a difference of
pressure and a resulting leak; they are expressed in g per
hour per source or in kg per year per site
Gas phase
Process fluid that is in the gaseous state at operating
conditions.
Inaccessible equipment
Equipment that for purpose of monitoring is more than 2
meters above a permanently accessible support surface or
equipment that is unsafe to monitor, which could expose
monitoring personnel to imminent hazard from temperature,
pressure, at risk concentration or equipment not accessible
because cover protected or insulated.
LDAR
Leak Detection and Repair Program: inspection and
maintenance program with the aim to identify, measure and
control fugitive emissions by repairing leaking equipment.
Leak level (or
concentration)
threshold Screening value above which equipment is identified as a
«leaker», and action is to be initiated in order to control the
fugitive emission.
Leak rate or leakage
percentage
Percentage of leaking equipment over the total population
of similar equipment, which have been measured.
Light liquid phase
Process phase for light liquid substance(s) of which at least
10% weight of the constituent substance(s) have a vapour
pressure greater than 0.3 kPa at 20ºC.
Mass emission rate
Mass flow of fugitive emission expressed in g per hour per
source.
Monitoring frequency
Period of time after which an equipment must be verified
for process leak
Open ended line (or valve)
A valve, except safety relief valves, having one side of the
valve seat in contact with process fluid and one side open
to the atmosphere, either directly or through open piping
PVC
Polyvinyl chloride.
Reference gas
Substance used for the calibration of the monitoring
instrument
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Response factor
Mathematical ratio of the actual concentration divided by
the unadjusted screening value. Represent the correction
factor to convert a reading obtained with an analyzer
calibrated with a reference gas different from the substance
or mix of substances being monitored
Similar equipment
Equipment that can be grouped in the same category for
the use of correlation equations, based on similar results of
bagging measurements; similar equipment can be further
grouped in several families for maintenance and follow up
purposes.
Speciation
The identification of each of the chemical species in a VOC
emission
Unadjusted screening value Concentration of volatile organic compound measured
close around equipment as determined by a monitoring
instrument, calibrated with a reference gas, according to a
defined protocol.
VCM
Vinyl chloride monomer.
VOC
Volatile organic compound, which has at standard
conditions at 20°C a vapour pressure of 0.3 kPa or more,
as for example EDC and VCM.
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2. OBJECTIVES
This reference method is dedicated to give guidance for ECVM plants (VCM/EDC/PVC
manufacturing units) in the identification, measurement and control of fugitive emissions
from equipment leaks.
The main objective is to reduce the fugitive emissions of VOCs and to carry on improvement
in all aspects of health, safety and environment at reasonable cost.
The second objective is to prepare annual emission reports based on a common reference
method.
3. SCOPE OF APPLICATION
The reference method and the correlation equations are intended to be used for the
quantitative determination of fugitive emission in VCM and PVC process units involved in the
ECVM survey (reference 1 and 2) and process units using the same design standards and
specifications for equipment and applying the similar maintenance programs.
The quantitative assessment is limited to process lines and equipment containing 10 % by
volume of VOC or more.
A detailed list of targeted categories of similar equipment and exemptions is defined in 5.3.

Remark
(a) The assessment of fugitive emissions from process units located inside enclosed and
ventilated buildings, obtained by multiplying the average concentration measured
continuously by a network of chromatographs in several representative points by the flow
rate of ventilation is considered by the ECVM as a valid reference method for the
purpose of quantification as an alternative to the point screening method described here.
(b) The detection of fugitive leaks in the process units in open air trough periodic walkaround by operators equipped with portable detectors close to locations where leaks are
likely to occur (valves arrangements, pumps areas, etc.) is also considered by the ECVM
as an efficient method to identify and reduce the most significant fugitive emissions to an
acceptable level, but not enabling a quantitative assessment nor accurate evaluation of
the performances according to the categories of equipment.
(c) The classical methods for leak detection already applied during assembly and building of
units after maintenance (soap solutions methods, pneumatic testing and hydraulic
testing) are also valid to detect the most important leaks, without enabling a quantitative
assessment nor an identification of small leaks.
In all aforementioned methods, in case of leak detection or increase of measured
concentration inside enclosed areas, the qualitative search at points for the immediate
identification of the source of the leak and the repair (see 2(d)) are also part of the
management for the control of fugitive emissions.
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ECVM considers that those methods are complementary and that their simultaneous
implementation justifies a targeted monitoring frequency according to level of performance
(see 4(b)).
4. ECVM PERFORMANCE GUIDELINES APPLICABLE FOR VCM AND EDC
Note: other performance guidelines could be defined for other VOC, according to their
economical value, environmental impact or effect on the health.
4.1

4.2

4.3



4.4
Leak Level Definition
A threshold leak level is defined as the detection of a VOC concentration of 1 000 ppmv
or more at the emission source using an appropriate hydrocarbon analyzer according to
the measurement protocol of section 5.5.
Leak Rate
The leak rate should not be more than 2% for any group of similar equipment monitored
inside a process unit.
Measurement Frequency
Monitor all accessible equipment at least one time in order to have a complete inventory
of equipment and to assess the leak rate of similar equipment.
Define a targeted measurement frequency according to leak rate established in previous
monitoring campaigns:
- If leak rate < 2 %: monitor similar equipment on a statistical mode in each family, so
that each equipment is verified within a defined period of time.
- If leak rate > 2 %: monitor on a systematic way all equipment of the family within a
defined period of time, for example, 1-3 years.
- If leak rate > 5 %: carry out an investigation in order to explain the repeated leaking
causes and to reduce them on an appropriate way; document the conclusions.
Monitor any equipment after repair.
Repair and Maintenance
The repair of leaks found during monitoring should be completed within short term
appropriate time schedule unless a plant shutdown is required or the number of equipment
requiring repair is beyond capability of the maintenance resources: in both cases, a record of
these exceptions and when they are corrected should be maintained.
Equipment that cannot be repaired without a unit shutdown will be identified and the repairs
will be planned for the next shutdown.
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4.5
Non-Accessible Equipment
The number of non-accessible equipment should be limited (typically < 20 % of similar
equipment); an estimate of fugitive emissions from that equipment shall however be included
in the annual emission report (see 6.2).
5. METHOD OF ASSESSMENT
5.1
Principle of the Method
Fugitive emission losses from process equipment are identified and quantified by following
these steps (see appendix C for extended description of the complete procedure):





5.2
Achieve complete equipment inventory (accessible and inaccessible equipment).
Measure accessible equipment by screening as per EPA Method 21 (section 5.5).
Report leaks for equipment with a leak  leak level threshold.
Repair leaks by routine maintenance for leak > leak level threshold; if leak persists,
repair again the leak if > 10000 ppm.
Establish a yearly emission report about fugitive emissions by using the ECVM
correlation equations and all (unadjusted) screening values. These equations relate the
actual concentrations (obtained by multiplying the unadjusted screening values with the
appropriate response factors) to mass emission rates that have been established for
European VCM/EDC/PVC plant process equipment. Correlations have been developed
for several categories of similar equipment by bagging equipment to measure mass
emissions of organic compound.
Inventory of Sources
The approach is to develop the inventory of emission sources. All the points are identified
from the list of equipment and process and instrumentation diagrams (P&IDs). All the lines
and equipment that are in service with > 10 % VOC at standard temperature and pressure
are targeted by the inventory. See Figure 5.1.
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Figure 5-1 : P&IDs Review and Points Numbering
5.3
Targeted Equipment
The type of similar equipment which constitutes categories of sources for fugitive emissions
and which have to be considered in the inventory count are:











Ball valves LL and G
Globe valves LL and G
Gate valves LL and G
Eccentric plug rotary valves LL and G
Plug valves LL and G
Other valves, like butterfly, plunger, diaphragm valves, etc.
Rotating equipment (pump seals, compressor seals, blowers)
Pressure relief valves LL and G
Equipment and piping flanges and connectors (LL and G)
Open ended lines LL and G
Sampling connections
Valves in service with gas (G) and light liquid (LL) are identified separately because the
emission correlation curves are dependent on the volatility.
Equipment of all sizes and all diameters should be considered in the inventory since
experience has shown that leaks can occur for any equipment size.
Equipment that is inaccessible for monitoring must still be included in the database. The
software used to manage the data has to estimate all non-monitored equipment using
statistical results of monitored equipment during the first inventory by type of equipment and
service.
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Exemptions
 Equipment in vacuum service (internal pressure  95 kPa) for > 90% of the time.
 Process streams containing > 90 % (volume based) non-organic compounds (i.e. steam,
hydrogen, nitrogen, air, etc.).
 Lines of small diameter for instrument connections can be excluded from a systematic
inventory and screening measurement if a low leak rate can be demonstrated by preliminary
appropriate checks; it is however recommended to include them in the assessment of the
total emission and in reports.
 Other channeled and diffuse emission sources (i.e. emissions released through stacks or
emissions from open sewer, open water surfaces, open equipment, etc) are not covered by
this program.
5.4
Database
To include inventoried emission sources, a database is developed. The database has to
include the following fields (see figure 5.2):








Process area
Source identification number
P&ID number
Process type (like PVC-suspension, PVC-emulsion, VCM, EDC)
Stream composition in % (ex.: VCM 100 %, VCM: water 90:10 %)
Phase (gas, light liquid)
Number of hours of operation under positive pressure per year
Equipment category (see 5.3)
And may include the additional fields:




Operating temperature (optional);
Operating pressure (optional);
Process line number
Piping size (optional).
Note that the chemical compositions entered in the database for each process line will allow for
the determination of the response factors of the process stream. The chemical compositions
also allow for the evaluation of total VOC emissions and specific compound emissions for
source points associated to a given process stream. The methodologies for the determination
of the response factors for a given chemical stream and for the evaluation of the emissions are
presented briefly in appendix E.
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Figure 5-2 : Database Elaboration (example using DÉFI1 Software)
5.5
Screening Measurements of Process Equipment
Fugitive emissions of VOC are monitored using Environmental Protection Agency (EPA)
Method 21 entitled Determination of Volatile Organic Compound Leaks (see Figures 5.3 and
5.4).
IMPORTANT REMARK: EPA Method 21 is intended to identify, locate and assess leaks
levels but not to quantify mass emission rates from individual sources. Dedicated ECVM’s
correlation equations (see Appendix D) are therefore required to link the screening value and
the emission rate from an equipment.
Measurement routes are established using the equipment and component inventory as per
the routing manual. During each measurement period (by shift or by day), the operators
carry out the following activities:
01
02
03
04
05
1
Calibration of the flame ionization detector (minimum of two, preferably at the
beginning and at the middle of the route) and maintenance of the analyzer.
Up-loading the measurement route from computer’s or any other database.
Measurement of the background concentration in each section of the plant in order to
subtract this value from the results stored in memory.
In situ measurements of the VOC concentrations for each emission point in
accordance with the EPA method 21 guidelines.
Transfer (by downloading) of the measurement results (unadjusted screening value
for each equipment) from the instruments data logger to the database.
US Patent #6,415,979BI
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06
Print/forward leak report on a regular basis to maintenance personnel to schedule
equipment repair.
Figure 5-3 : Measurement of VOC Emissions
VOC leaks are measured using a portable ionization analyzer equipped with a data logger.
The analyser’s VOC measurement range varies from around 0.5 to  20 000 ppm in
equivalent CH4, thus allowing the unadjusted screening value to be established and the leaks
to be identified. Response factors specific to the analyser are given by the manufacturers to
transform the measurements results from equivalent CH4 to COV.
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Figure 5-4 : Application of Response Factor and Correlation Equation
CORRELATION EQUATION
Analyser’s
response factor
ppm CH4
equivalent
Correlation equation
Emission
kg/h
Total VOC
=  (RF X SV) 
determined by
bagging
SNCLAVALIN
Environment
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Calibration is to be done with the use of span gases at certified concentration.
The portable analyser used in Europe must be approved for use in explosible area zones
according to CENELEC Gas Group II C, Zone 1 and Zone 2, thus ensuring safe operation in
petrochemical environment.
6. TYPICAL REPORTS GENERATED
6.1
Leaking Equipment Report
A leak report is given to the maintenance team after each period of measurements. This
report contains the information that will enable to retrace the leaks that were found and make
the repairs (see Appendix A for an example of leak report generated by computer and
dedicated database).
6.2
Emission Report
An emission report summarizes the information obtained during the measurement program
(see Appendix B for an example of an emission report).
The fugitive emission report gives an annual mass emission rate for total VOCs and should be
able to provide an annual mass emission rate for all the substances included in the database.
The chemical compositions of the process streams must be included in the database to
speciate the emissions per chemical. The results are given in kg of chemical emitted by year.
The report will include for each category of equipment:







Number of sources measured.
Mass emission from all equipment measured.
Number equipment and equipment with leaks.
Estimate of non-accessible equipment.
Number of equipment repaired or replaced.
Estimate of mass emission for repaired equipment, before and after repair.
Proportion of emission from each category of equipment.
Estimate of emission from equipment not measured (including non accessible equipment) is
made preferably based on mass emissions rate obtained form the first inventory for this
category of equipment or either on average unadjusted screening values of the random
sampling.
These reports can be generated automatically by any software using the ECVM’s correlation
equations for VCM/EDC/PVC production plants.
7. REFERENCE DOCUMENTS
 Environmental Code of Practice for the Measurement and Control of Fugitive VOC
Emissions from Equipment Leaks, Canadian Council of Ministers of the Environment
(CCME), PN 1106, October 1993
ECVM Reference Method
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 ECVM-Specific Correlation Equations, Final Report, European Council of Vinyl
Manufacturers, September 2004, SNC Lavalin Environment
 Protocol for Equipment Leak Emissions Estimates, EPA-453/R-95-017, US Environmental
Protection Agency, 1995
 Reference Method 21, Code of Federal Regulations, Title 40, Part 60, Appendix A.,
Determination of Volatile Organic Compound Leaks. Washington DC. US Government
Printing Office, 2000.
8. RESOURCES PERSONS
Mr. Roger Liégeois
Competence Centre for Health, Safety, Environment (CC-HSE)
Solvay S.A.
rue de Ransbeek 310
B-1120 Brussels
Belgium
Telephone:
Fax:
Email:
32 02 2642977
32 022643475
roger.liegeois@solvay.com
Mr. Jean-Luc Allard
SNC-Lavalin Environment Inc.
2271, Fernand-Lafontaine Blvd.
Longueuil, Quebec
Canada J4G 2R7
Telephone:
Fax:
Email:
1 (450) 651-6710
1 (450) 651-0885
jeanluc.allard@snclavalin.com
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Appendix A
Example of a Leak Report
SITE
UNIT
YEAR
YYY
PVC-S abc
1999
EQUIPMENT
INVENTORY
LEAK STATUS
inspected
not
total inventory inspected
units
agitator
flange
open end line
valve
pump
PSV
TOTAL
n
5
750
15
25
7
5
807
leak level definition :
minimal specified composition % :
points included
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author
date :
approved :
date :
FUGITIVE EMISSION OF VOC
ANNUAL LEAK REPORT
n
0
55
2
5
2
1
65
without
leak
n
4
685
13
19
4
4
729
1000
10
all
with leak
n
1
10
0
1
1
0
13
leak rate
%
20%
1%
0%
5%
20%
0%
2%
repaired
leak
n
0
2
0
1
1
0
4
leaks to
be
repaired
n
1
8
0
0
0
0
9
not inspected equipment :
AAA
01-févr-00
BBB
10-févr-00
EMISSION
kg/y
100
250
0
200
500
235
1285
8%
October 2004
Appendix B
Example of Emission Reports
SITE
UNIT
YEAR
YYY
PVC-S abc
1999
FUGITIVE EMISSION OF VOC
ANNUAL EMISSION ESTIMATE
SCREENING RESULTS
EQUIPMENT
phase measured estimated
n
n
agitator
gas
5
0
flange
gas
1620
122
light liquid
820
62
open end line light liquid
150
50
valve
gas
1100
100
light liquid
250
50
pump
light liquid
8
11
relief valve
gas+ligh liq
25
25
TOTAL
3978
420
leak level definition :
minimal specified composition % :
points included
author
date :
approved :
date :
1000
10
all

0,0000606
0,00000148
0,00000148
0,00000709
0,00000449
0,00000416
0,0000606
0,0000606

0,473
0,816
0,816
0,53
0,554
0,585
0,47
0,47
AAA
01-Feb-00
BBB
10-Feb-00
EMISSION
average
factor
reference
factor
g/h.source
g/h.source
0,016
0,020
0,035
0,053
0,028
0,028
0,099
0,187
4,000
0,080
0,080
0,640
0,680
0,680
4,000
0,500
stream
factor
h/y
8760
8760
8685
8760
8000
8000
8760
8000
kg/y
1
366
295
350
790
328
392
137
2659
reference to ECVM correlation curves and emission factors
proportion of estimated emissions
10,6%
average factor : relates to the average of the results obtained from all measurements by screening and corresponding mass
emission values derived from correlation equations for each equipment monitored
reference factor : relates to the emission factor obtained for that category of equipment during the first inventory (obtained
from ECVM survey or from the site first inventory) and applied to equipment which have not been measured (not accessible or
not
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Appendix C
Implementing a Leak Detection and Repair Program
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Implementing a Leak Detection and Repair Program
01
Arrange safety training of personnel that will work on plant site.
02
Organize a visit of the plant site.
03
Collect the information on the plant and process: drawings, Process and
Instrument Diagrams (P&ID), Process and Flow Diagrams (PFD), equipment
layout, equipment list, process line operation time, etc.
04
Identify, on the drawings, the process lines that will be included in the program.
05
Validate, on-site, the drawings used. Make necessary corrections and updates.
06
Identify, on the drawings, each potential fugitive emission source.
07
List these sources in an appropriate database by giving them a unique
identification or tag number.
Ideally, the link between the database and an
analyzer should be possible.
08
Include, for each point in the database, mandatory information to eventually
calculate emissions: type of equipment, phase of process line and hours of
operation of the process line.
09
Include for each point in the database other information: P&IDs number,
characteristics of the point, description, process line number, composition of the
process line, temperature and pressure of the process line, etc. (optional).
10
Choose a method to identify, on site, every point that will be measured (barcodes,
pictures, drawings, etc.).
11
Prepare the measurement routes, carefully minimizing time loss.
12
Make necessary acquisition of calibration gases and hydrogen (if using an FID
detector) for the analyzer.
13
Calibrate the analyzer each day (see analyzer manual).
14
Upload the measurement route into the portable analyzer.
15
Measure the potential fugitive emission sources using a portable ionization
analyzer equipped with a data acquisition instrument. The analyzer should be
chosen depending on the types of gases in the process lines. The analyzer
should be approved by Cenelec Gas Group II C, Zone 1 and Zone 2, thus
ensuring safe operation within petrochemical environment. The analyzer should
also allow precise characterization of emission standards.
16
Download the measurements into database.
17
Generate the leak report.
personnel.
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Leak reports should be given to the maintenance
October 2004
18
Repair leaking equipment within a reasonable period.
19
Follow-up on the monitored leaks to confirm repairs as described in 15.
20
Generate annual emission reports after the measurement campaign is over.
21
Analyze the data and decide when the next monitoring round should be performed
based on those results (see ECVM performance guidelines).
22
Decide on required or appropriate monitoring frequency of the various families of
equipment based on the results of the analysis.
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Appendix D
ECVM Correlation Curves
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ECVM Correlation Curves for EDC/VCM/PVC Units:
Final Edition August 2004
Mass Emission = alpha x (actual concentration)beta
For measured (uncorrected) concentration between 1 and 10 000 ppmv
Alpha
All flanges1
All valves 2
Relief valve
Rotating Equipment
Open end line
1
2
LL+G
G
LL
LL+G
LL+G
G + LL
0.00000148
0.00000449
0.00000416
0.0000606
0.0000606
0.00000709
Beta
0.816
0.554
0.585
0.470
0.470
0.530
including self-contained check valves
excluding self-contained check valves and relief valves
For a source with a measured (uncorrected) concentration is below 1 ppmv, the previous
correlation equations should not be used. The following “default zero” emission factors should
be used instead, by equipment type.
Equipment
Phase
Default zero value (kg/h-source)
1
All valves
Light liquid + gas
0.0000054
Flanges & check valves
Light liquid + gas
0.00000298
Open-ended lines
Light liquid + gas
As valves
Rotating equipments
Light liquid + gas
0.0000207
1 excluding self-contained check valves and relief valves
For a source with a measured (uncorrected) concentration above 10 000 ppmv, the previous
correlation equations should not be used. The following “pegged value” emission factors
should be used instead, by equipment type.
Equipment
Phase
All valves1
Light liquid
All valves1
Gas
Flanges & check valves
Light liquid + gas
Open-ended lines
Light liquid + gas
Rotating equipments
Light liquid + gas
1 excluding self-contained check valves and relief valves
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10 000 + ppmv pegged value
(kg/h-source)
0.00614
0.0177
0.044
0.00607
0.0146
October 2004
Appendix E
Response factors and chemical speciation
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Response factors and chemical speciation
The response factor is the mathematical ratio of the actual concentration divided by the
unadjusted screening value. It represents the correction factor to convert a reading obtained
with an analyzer calibrated with a reference gas different from the substance or mix of
substances being monitored. It is expressed as follow:
Response factor = actual concentration / screening value (unadjusted)
Response factors are specific to a model of analyzer and are defined experimentally by the
manufacturers for 500 and 10 000 ppmv of actual concentration.
The associated screening values are the unadjusted screening value equivalent to each of
the two actual concentration of 500 and 10000 ppmv for which the response factors are
defined. They are obtained by reversing the equation previously mentioned:
Associated unadjusted screening value = actual concentration / Response factor
A linear interpolation is performed between the two associated screening values to estimate
the response factor at any given (unadjusted) screening value.
According to section 2.4.2 of the USEPA protocol, no extrapolation can be done to obtain
response factors beyond the endpoints.
The response factors specified by the
manufacturers for the endpoints (500 and 10 000 ppmv) were used to correct unadjusted
screening values outside of the interpolation range.
In case of a mixture of substances, the response factors (for both 500 and 10 000 ppmv) can
be calculated for that mixture, according to the method established by the EPA. The
equation used is as follow:
Re sponse factormix 
1
  xi RFi 
Where xi is the molar fraction of compound i and RFi is the response factor of compound i;
specific to the analyzer used.
The mass emissions evaluated by the correlation equations are nominally expressed according
to the reference gas used for the calibration of the analyzer (ex.: equivalent methane). If
chemical-specific response factors are used, this mass emission can therefore be expressed in
term of total VOC emissions.
The next refinement is the inclusion of the chemical composition of each process stream. The
chemical compositions are actually required for the accurate determination of response factors
as seen in the equation above. The chemical compositions (percentage of all constituents in a
process stream) are then used to perform the breakdown of the total VOC emissions and
obtained emissions by chemical.
ECVM Reference Method
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October 2004